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Title: Development of New Generation Hybrid Lithium-Ion Battery Capacitor Energy Storage Devices.
Creator: Hagen, Mark A. (Mark Andrew), Zheng, Jianping, Shih, Chiang, Andrei, Petru P., Foo, Simon Y., Li, Hui, Florida State University, FAMU-FSU College of Engineering, Department of...
Show moreHagen, Mark A. (Mark Andrew), Zheng, Jianping, Shih, Chiang, Andrei, Petru P., Foo, Simon Y., Li, Hui, Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: As the energy demand grows so to do the need for devices that can be tailored to a design need. Often, this can lead to a device that falls between the two traditional groups of lithium-ion battery (LIB) and lithium-ion capacitors (LIC). An emerging way to bring these devices together is using composite cathodes. Composite cathodes combine a battery material with capacitor material and have shown to be able to enhance life cycle energy and power performance compared to their non-composite...
Show moreAs the energy demand grows so to do the need for devices that can be tailored to a design need. Often, this can lead to a device that falls between the two traditional groups of lithium-ion battery (LIB) and lithium-ion capacitors (LIC). An emerging way to bring these devices together is using composite cathodes. Composite cathodes combine a battery material with capacitor material and have shown to be able to enhance life cycle energy and power performance compared to their non-composite counterparts. The initial focus of the investigation is into the performance impact of LiNi0.5Co0.2Mn0.3O2 (NMC) as an additive to Activated Carbon (AC) electrodes within a high-performance Li-ion capacitor fabricated with activated carbon positive electrodes (PEs) and hard carbon negative electrodes (NEs) having lithium thin film as Li sources loaded on the surface of the negative electrodes. We report here on a hybrid LIC consisting of a Lithium nickel cobalt manganese oxide /activated carbon composite cathode in combination with an ultra-thin lithium film (u-Li) pre-loaded hard carbon anode. Additionally, we show that by utilizing three design approaches: dry composite electrode fabrication method, cathode to anode capacity ratio design, and pre-lithiation method using u-Li, we can demonstrate an energy storage device with excellent cycle life, and that can be tailored by composite ratios within the cathode to fit different applications. Shown here is an in-depth look at various composite material ratios, pre-lithiation calculations, and hybrid lithium-ion battery-capacitor energy storage device creation based on targeting essential energy-power performance characteristics.
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Date Issued: 2019
Identifier: 2019_Spring_Hagen_fsu_0071E_15035
Format: Thesis

Title: Shape Data Analysis for Machine Learning in Power Systems Applications.
Creator: Cordova Guillen, Jose David, Pamidi, Sastry V., Srivastava, Anuj, Ozguven, Eren Erman, Li, Hui, Foo, Simon Y., Florida State University, FAMU-FSU College of Engineering,...
Show moreCordova Guillen, Jose David, Pamidi, Sastry V., Srivastava, Anuj, Ozguven, Eren Erman, Li, Hui, Foo, Simon Y., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: This dissertation proposes the use of the shape of data as a new feature to improve and develop new in machine learning and deep learning algorithms utilized for different power systems applications. The new features are obtained through Shape Data Analysis (SDA), an emerging field in Statistics. SDA is used to obtain the shape of the data structure to observe different patterns developed under distribution networks abnormal conditions, as well as determining the shape of load curves to...
Show moreThis dissertation proposes the use of the shape of data as a new feature to improve and develop new in machine learning and deep learning algorithms utilized for different power systems applications. The new features are obtained through Shape Data Analysis (SDA), an emerging field in Statistics. SDA is used to obtain the shape of the data structure to observe different patterns developed under distribution networks abnormal conditions, as well as determining the shape of load curves to improve existing electrical load forecasting algorithms. Specifically, shape-based data analysis is implemented and developed for two different applications: electrical fault detection and electrical consumption short-term load forecasting. The algorithms proposed are implemented on data collected from Intelligent Electronic Devices (IEDs), Phasor Measurement Units (PMUs), and Supervisory Control and Data Acquisition (SCADA) systems in power distribution networks.
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Date Issued: 2019
Identifier: 2019_Spring_CordovaGuillen_fsu_0071E_12807
Format: Thesis

Title: Optimization of Energy Transfer during Active Balancing of Lithium-Ion Batteries.
Creator: Sonavane, Rohit Ganesh, Moss, Pedro L., Weatherspoon, Mark H., Foo, Simon Y., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer...
Show moreSonavane, Rohit Ganesh, Moss, Pedro L., Weatherspoon, Mark H., Foo, Simon Y., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Balancing is one of the most important function of any battery management system (BMS). We need it to adjust all the batteries in the system for them to work efficiently, based on battery voltage or state-of-charge (SOC). One of the most common and easier ways to achieve cell balancing is by using active or passive cell balancing techniques. Active balancing is when you equalize a battery or a cell with another battery with higher potential. Active balancing is widely implemented method as it...
Show moreBalancing is one of the most important function of any battery management system (BMS). We need it to adjust all the batteries in the system for them to work efficiently, based on battery voltage or state-of-charge (SOC). One of the most common and easier ways to achieve cell balancing is by using active or passive cell balancing techniques. Active balancing is when you equalize a battery or a cell with another battery with higher potential. Active balancing is widely implemented method as it is cheap, but it is not as optimum and efficient as compared to the new methods like pulse charging. In this proposed study, we have a dynamic topology for active balancing method that would give us optimized results, with faster balancing and an expandable system for ‘n’ number of batteries or cells. We have reduced the charge and discharge time, removing the delays that many existing systems faces. We achieved it in both simulations and experimental testing. It also, enables in improved charging that does not allow the stack to fail. The use of microcontrollers has proved to reduce the switching time and optimize the results. These switches are precisely controlled hence saving the amount of time needed in charge and discharge cycles. This topology uses an inductor, which is the main component for charge transfer. When charge is transferred from one battery to the other we use inductor as the medium. This inductor basically stores the charge in the first cycle and then dumps it onto the battery in the second cycle. This topology also includes an external charger that keeps charging the stack while equalization takes place. This improves the charging and balancing time for the entire stack.
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Date Issued: 2019
Identifier: 2019_Spring_Sonavane_fsu_0071N_14941
Format: Thesis

Title: A Steady-State Stability Analysis of Uniform Synchronous Power Grid Topologies.
Creator: Stright, James, Edrington, Christopher S., Oates, William, Faruque, Omar, Andrei, Petru P., Florida State University, FAMU-FSU College of Engineering, Department of Electrical...
Show moreStright, James, Edrington, Christopher S., Oates, William, Faruque, Omar, Andrei, Petru P., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Electric power grids are evolving rapidly as increased emphasis is placed on integration of renewable resources into existing power infrastructures and as new paradigms for power production and distribution, such as microgrids, are developed. Resultant grid configurations must meet the needs and requirements of existing and evolving population distributions, feasible production facilities placement, and environmental stewardship associated with power transmission and distribution...
Show moreElectric power grids are evolving rapidly as increased emphasis is placed on integration of renewable resources into existing power infrastructures and as new paradigms for power production and distribution, such as microgrids, are developed. Resultant grid configurations must meet the needs and requirements of existing and evolving population distributions, feasible production facilities placement, and environmental stewardship associated with power transmission and distribution infrastructures. In most developed regions, large-scale transmission infrastructures are well established, and their geographic routing is increasingly difficult to alter or amend. Renewables integration, however, directs far more attention at the power distribution level. As more local power is produced, often intermittent in nature and sometimes by consumers themselves, power distribution becomes more problematic in several respects. Conceptually, “the grid” becomes less a fixed entity and more an ever-changing amalgam of sources, loads, and preferred routes among them. All such routes must meet certain fundamental physical requirements, such as current and voltage handling capabilities. For power quality and reliability reasons, however, they also need to be “stable” in several senses, and there is currently no comprehensive approach to selecting available or potential routes to optimize the resultant “stability” of the configuration, in any of the various senses. This work develops such an approach, applicable to the steady-state stability of grids subject to several simplifying constraints. That is, it provides a framework for analyzing the steady-state stabilities of all grid topologies for grids that meet those constraints. The approach is general and abstract in nature, as this work focuses not on particular commonly studied grids but instead on the characteristics of grid topologies that lend themselves to greater or lesser degrees of steady-state stability. As a baseline study, only grids having synchronous generators are considered, with the expectation that future work will adapt inertia-based models of renewable sources to this or a similar approach. Although the approach itself is the main contribution, several interesting discoveries have already been made regarding optimal configurations of some simple topologies and on quantifying how richness of grid interconnections influences grid steady-state stability.
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Date Issued: 2019
Identifier: 2019_Spring_Stright_fsu_0071E_15115
Format: Thesis

Title: High Voltage Insulation Systems for Gas-Cooled Superconducting Power Devices.
Creator: Al-Taie, Aws Habeeb Mohammed, Pamidi, Sastry V., Ordóñez, Juan Carlos, Foo, Simon Y., Graber, Lukas, Anubi, Olugbenga Moses, Florida State University, FAMU-FSU College of...
Show moreAl-Taie, Aws Habeeb Mohammed, Pamidi, Sastry V., Ordóñez, Juan Carlos, Foo, Simon Y., Graber, Lukas, Anubi, Olugbenga Moses, Florida State University, FAMU-FSU College of Engineering (Tallahassee, Fla.), Department of Electrical and Computer Engineering
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Abstract/Description: Demand for electrical power is increasing around the globe to keep up with the ever-increasing annual load growth, which in turn requires new power sources to be installed. As a society, there is a greater emphasis for power sources to be environmentally friendly, such as wind and solar. For large-scale wind and solar power sources, electric utilities need to install them in the optimal regions which are generally far away from the load centers. Hence, efficient and high capacity power...
Show moreDemand for electrical power is increasing around the globe to keep up with the ever-increasing annual load growth, which in turn requires new power sources to be installed. As a society, there is a greater emphasis for power sources to be environmentally friendly, such as wind and solar. For large-scale wind and solar power sources, electric utilities need to install them in the optimal regions which are generally far away from the load centers. Hence, efficient and high capacity power transmission solutions are required to integrate these energy sources into the power grid. Another new trend of electrifying the transportation sector with electric ships and aircrafts requires compact electric power devices with high volumetric and gravimetric power densities. Therefore, electric utilities and the transportation sector have been exploring innovative solutions for energy efficient and high-power density technology options, which include utilizing superconducting power devices. High temperature superconducting (HTS) power cables and other devices have been developed and installed in several countries around the world to achieve more efficient and significantly compact devices compared to their copper counterparts. A long-term vision for the future power transmission is a cross-country multi-terminal DC HTS cable transmission system. Gas-cooled HTS power cables are being explored for electric transportation applications, including aircrafts and ships, due to asphyxiation risks associated with liquid nitrogen. Use of a gas as the cryogen instead of a liquid, however, poses technical challenges resulting from the reduced heat capacity and lower dielectric strength which could affect the overall performance of HTS cables. When helium gas is used as the cryogen in HTS power devices, the electrical insulation method and materials utilized for liquid nitrogen cooled HTS cables are not applicable. For liquid nitrogen cooled HTS power cables for electric utility applications, lapped tape insulation has been used to achieve operating voltages in excess of 100 kV. When this same design is utilized for electrical insulation system of helium gas cooled HTS cables, partial discharge (PD) occurs at voltages <10 kV, limiting the operational voltages. The butt gaps within the lapped tape insulation layers trap helium gas and cause the associated field enhancements leading to low partial discharge inception voltages. The research described in this dissertation focused on extending the understanding the technology challenges associated with the use of gas media as part of the electrical insulation system at cryogenic temperatures. The emphasis was on the development of the concept of superconducting gas insulated line (S-GIL) as an alternative to lapped tape electrical insulation system to HTS power cables to enable higher operating voltages for helium gas cooled HTS power cables. The S GIL, which is similar to the Gas Insulated Line (GIL), was conceptualized recently at Florida State University's Center for Advanced Power Systems (FSU-CAPS). The S-GIL utilizes the flow of pressurized cryogenic gas instead of stagnant room temperature gas for GIL. The S-GIL addresses the challenge of low partial discharge inception voltages (PDIV) in lapped tape insulated, gas cooled HTS cables by eliminating the need for solid insulation layers on the cable. However, the need to maintain the cable on the axis of the cryostat imposes the requirement of insulator spacers. This work explored bundled tubular spacers for S-GIL as an option for spacers and 1-m long prototype cables were fabricated and characterized in gaseous helium and helium-based gas mixtures. Surface flashover along the surface of the spacers is expected to be one of the design factors which influences the voltage rating for S-GIL. The designs considered different tube materials and gases and a variety of experiments were conducted at room temperature and at cryogenic temperatures to gain a thorough understanding of the S-GIL design limitations. To gain further understanding of the limits of the S-GIL concept, the design was tested with liquid nitrogen as the insulation medium to decipher the role of the intrinsic dielectric strength of the insulation medium. Besides providing additional insights into S-GIL concept, the liquid cooled alternative will have applications in terrestrial power systems and transportation sector where higher operating voltages and efficient thermal designs are needed. The research also focused on investigating the surface flashover phenomenon in GHe environment. This included investigating the triple point where the conductor, solid insulation material, and gas insulation media meet. Surface flashover measurements were performed with varying gas density, temperature, gas composition, solid insulation material, applied voltage waveform, and electric field strength and distribution.
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Date Issued: 2019
Identifier: 2019_Summer_AlTaie_fsu_0071E_15386
Format: Thesis

Title: A Novel Approach for AI Based Driver Behavior Analysis Model Using Visual and Cognitive Data.
Creator: Bhattacharya, Sylvia, Bernadin, Shonda, Sobanjo, John Olusegun, Foo, Simon Y., Roberts, Rodney G., Florida State University, FAMU-FSU College of Engineering (Tallahassee, Fla.),...
Show moreBhattacharya, Sylvia, Bernadin, Shonda, Sobanjo, John Olusegun, Foo, Simon Y., Roberts, Rodney G., Florida State University, FAMU-FSU College of Engineering (Tallahassee, Fla.), Department of Electrical and Computer Engineering
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Abstract/Description: In recent years there has been increasing research on incorporating intelligent driver assistance systems (IDAS) into vehicular platforms to help drivers make better driving decisions and to make the roadways safer. The percentage of highway accidents in United States is steadily increasing every year. Current IDAS such as collision detection and avoidance systems use models of human behavior to improve the reliability of these systems and to help decrease driver workload. Modeling driver...
Show moreIn recent years there has been increasing research on incorporating intelligent driver assistance systems (IDAS) into vehicular platforms to help drivers make better driving decisions and to make the roadways safer. The percentage of highway accidents in United States is steadily increasing every year. Current IDAS such as collision detection and avoidance systems use models of human behavior to improve the reliability of these systems and to help decrease driver workload. Modeling driver behavior is not a simple task. It involves aspects of psychology, physiology, data analysis, signal processing and engineering, to name a few. In the case of lane changing events, early detection of a driver's intent to change lanes can be beneficial to systems that involve vehicle- to- vehicle communications. Moreover, a lane change prediction system, could be integrated into automatic aviation of the turn signal. Most published studies of lane change events are based on large scale vehicle trajectory data i.e steering angle, velocity and accelerations. Using this approach, a lane change prediction event is typically detected as soon as the driver initiates a lane change maneuver. Most vehicular trajectory model fails when a driver forgets to enable a turn signal before making a lane change. Hence, irrespective of having many automatic features equipped in modern day cars, the accident rate is still not decreasing. In such cases, biomedical signals may play an important role in detecting early driver intention. Besides vehicle dynamics (lane change, braking, acceleration), it is also important to understand the mental workload of the driver to maintain safety while travelling. Mental workload is directly related to distracted or non- distracted driving which varies with emotional changes. The mental workload can tremendously impact driving behavior and hence the detection of these factors will add driver safety on roadway. In this dissertation, we propose to utilize visual and cognitive information to detect a driver's intent to change lanes and predict their mental distraction. Mental workload varies in different situations. For example, the amount of focus required during a lane change maneuver can be disrupted due to a secondary task like cell phone usage, talking to a co-passenger, a baby crying in the back seat or an unexpected news broadcasted on the car radio. Most of the research focuses on distracted driving using a cell phone, although more number of accidents are accounted on highways during talking to passengers. In this research, conversational task with co –passengers are considered as a situation, for intent analysis and cognitive workload analysis of the driver. A novel approach is developed that considers eye movements and cognitive attentiveness as distraction levels are increased during two different scenarios (i) single passenger driving and (ii) driving with passengers. This involves aspects of statistical analysis, signal processing, software engineering and machine learning techniques. Different types of statistical analysis techniques like normalization, correlation models are used in this research. Software development with TCL scripting is utilized to design real time virtual scenario for data collection. Signal Processing techniques like power spectral analysis, cognitive engagement ratio etc. are utilized to analyze brain signals. Artificial Intelligence methods are applied to help make accurate predictions of driver intent. Finally, Artificial Intelligence is a broad field that uses deep learning and machine learning algorithms to mimic human cognition. This research utilizes innovative machine learning tools like sklearn and tensor flow, to automate the process of behavior analysis. This work will inform research on lane-change prediction, behavior prediction and vehicular feedback analysis using an IDAS environment. Furthermore, this work considers factors that may impact the lane change detection and prediction of differential drivers including elderly drivers. This work also contributes an individual database that records driving behaviors during conversational tasks that other researchers can use to conduct behavior analysis research associated with this driving scenario. To author's knowledge this is the first database that will be made available publicly for use in conversational task scenario in driving. This dissertation is composed of five chapters. Chapter 1 presents the introduction and back ground of IDAS research. It highlights various factors that contribute to detrimental road crashes and describes the research gap in this field. Chapter 2 includes a detailed literature review of all the studies that has been conducted in this field and also includes essential biological and artificial intelligence methods that are important to know in order this field. Chapter 3 outlines the methodology that has been adopted in this project. It includes description of virtual reality development procedure for collecting data from driver simulator, data collection procedure for various parameter in this research and also describes the mathematical models of each concept. Chapter 4 consists of results, discussion and the importance of novel distraction recognition algorithm. Finally, conclusion, limitations and future work are discussed in chapter 5.
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Date Issued: 2019
Identifier: 2019_Summer_Bhattacharya_fsu_0071E_15258
Format: Thesis

Title: Improved MCVDC Breaker Operation by Existing Power Converters in Shipboard Applications.
Creator: Xie, Ren, Li, Hui, Zhang, Jinfeng, Peng, Fang, Zheng, Jianping, Steurer, Michael, Florida State University, FAMU-FSU College of Engiineering, Department of Electrical and...
Show moreXie, Ren, Li, Hui, Zhang, Jinfeng, Peng, Fang, Zheng, Jianping, Steurer, Michael, Florida State University, FAMU-FSU College of Engiineering, Department of Electrical and Computer Engineering
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Abstract/Description: The medium voltage dc (MVDC) power system is gaining increasing attention in applications such as renewable energy and shipboard power systems due to its advantages in reliability, efficiency, power quality and power density. However, the short-circuit fault management in a MVDC system is a key issue because of the lack of natural zero-crossing point and conventional mechanical circuit breaker (CB) design challenge. So solid state CBs (SSCB) or hybrid CBs (HCB) are under development to enable...
Show moreThe medium voltage dc (MVDC) power system is gaining increasing attention in applications such as renewable energy and shipboard power systems due to its advantages in reliability, efficiency, power quality and power density. However, the short-circuit fault management in a MVDC system is a key issue because of the lack of natural zero-crossing point and conventional mechanical circuit breaker (CB) design challenge. So solid state CBs (SSCB) or hybrid CBs (HCB) are under development to enable the breaker-based fault protection approach. Another breaker-less approach utilizing the inherent current-limiting capability of power semiconductor devices is also promising in a MVDC system. The state-of-the-art of the two fault management approaches are reviewed. This thesis is focused on developing a technology originated from the breaker-less method to improve the performance of breaker-based fault protection approach. In the shipboard breaker-based MVDC system, converters are normally shut down to react to the fault. The diodes freewheeling phenomenon is a concern but a quantitative analysis is still not available. Moreover, the potential of converter during fault has not been exploited completely. Considering large number of converters already existing in the shipboard MVDC system, the overall benefits at no extra hardware cost may be significant. Therefore, a converter fault ride through (FRT) strategy aiming at improving CB operation is proposed in this thesis. The proposed research found that there are some converters located in parallel with activated CBs during the fault and thus, active fault current sharing (FCS) by these converters are possible. In addition, this peak fault current reduction effect on CBs can be amplified from the systematic perspective because multiple CBs in various fault scenarios can be benefited from a single converter. As a first step, the short-circuit fault scenarios of a shipboard breaker-based MVDC system are analyzed comprehensively and fault equivalent circuits including power converters adjacent to CBs are developed. The equivalent circuits are analyzed mathematically and the reaction of passive mode converters to the fault are discussed, which can be a benchmark to evaluate the proposed active FCS strategy. Next, the proposed converter FCS strategy to reduce the CB fault current is illustrated in detail, together with the device stress analysis. Finally, the experimental verifications on a down-scaled test setup are provided.
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Date Issued: 2019
Identifier: 2019_Summer_Xie_fsu_0071E_15185
Format: Thesis

Title: The Study of Prelithiation Strategy for Graphite/Span Li-Ion Battery.
Creator: Ye, Donghao, Zheng, Jianping, Andrei, Petru, Foo, Simon Y., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: Lithium-sulfur (Li-S) batteries with a theoretical specific energy density up to 2600 Wh/kg is regarded as one of the most promising energy chemical power systems. However, the development of Li-S batteries still faces numerous technical challenges. Both sulfur and Li2S is electrically insulating, leading to a low power capability; the polysulfide generated during the charging and discharging processes is highly soluble in electrolytes, resulting in loss of active material and severe redox...
Show moreLithium-sulfur (Li-S) batteries with a theoretical specific energy density up to 2600 Wh/kg is regarded as one of the most promising energy chemical power systems. However, the development of Li-S batteries still faces numerous technical challenges. Both sulfur and Li2S is electrically insulating, leading to a low power capability; the polysulfide generated during the charging and discharging processes is highly soluble in electrolytes, resulting in loss of active material and severe redox shuttle effect. To address above these issues, sulfurized polyacrylonitrile (SPAN) has been developed as a novel composite cathode material. The strong bonding between sulfur and polyacrylonitrile enables SPAN cathode to operate in the commercial carbonate-based electrolyte with an exceptional cycle ability, inhibiting the shuttle effect and self-discharge phenomenon observed in conventional Li-S batteries. In this study, a freestanding SPAN-CNT composites are developed as the cathode material for Li-S batteries, which is capable to deliver a high specific capacity of 1303 mAh/g at 0.2C and a desirable high-rate performance of 1085 mAh/g at 2.0C. Furthermore, Li-ion sulfur full batteries based on SPAN-CNT composites cathode and graphite anode were assembled using a pre-lithiation method. Both the cathode and anode pre-lithiation method was investigated for the optimization of system performance. With a high specific capacity and good cycle life, the proposed Li-ion sulfur full battery system provides an alternative approach to fabricate safe and low-cost metal-free Li-ion batteries.
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Date Issued: 2019
Identifier: 2019_Fall_Ye_fsu_0071N_15578
Format: Thesis

Title: Active Thermal Management and Fault-Tolerant Control for Switching Power Converters with Sequence-Based Control.
Creator: Ozkan, Gokhan, Pamidi, Sastry V., Ordóñez, Juan Carlos, Edrington, Christopher S., Foo, Simon Y., Anubi, Olugbenga Moses, Florida State University, FAMU-FSU College of...
Show moreOzkan, Gokhan, Pamidi, Sastry V., Ordóñez, Juan Carlos, Edrington, Christopher S., Foo, Simon Y., Anubi, Olugbenga Moses, Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: With the developments in semiconductor technology, power electronic devices have had a crucial role in power systems. They are employed in a different variety of applications, including but not limited to energy conversation and grid connection for renewable energy sources, motor drive systems in electric vehicles and industrial systems, and AC/DC power conversion in the ship power system (SPS). Especially, medium-voltage DC (MVDC) distribution systems are highly interested in future ship...
Show moreWith the developments in semiconductor technology, power electronic devices have had a crucial role in power systems. They are employed in a different variety of applications, including but not limited to energy conversation and grid connection for renewable energy sources, motor drive systems in electric vehicles and industrial systems, and AC/DC power conversion in the ship power system (SPS). Especially, medium-voltage DC (MVDC) distribution systems are highly interested in future ship power systems, therefore, power converter devices and their control systems will be commonly used in the ship. The increasingly using of power electronics in power systems leads to new challenges including but not limited to reducing Total Harmonic Distortion (THD) and system cost, improving reliability and lowering the system complexity. In addition, some of the applications may have limited weight and space capacity such as wind turbines and SPS. Thus, the weight and size of the power converter and its cooling system should be taken into account. To minimize the size of the power converters, high-frequency switching is used to reduce the required passive filters. However, this causes additional thermal stress on semiconductor switches due to increasing of the switching losses which also have a negative impact on the cost of energy. Power converters and their control algorithm must provide highly efficient power conversion to reduce the cost of wasted power and energy dissipation to minimize the necessary cooling system. In addition to this, the aging and losses of switching devices in the power converter are mainly related to its junction temperature. One of the main approaches to improve the lifetime of semiconductors is the ability to control the junction temperature of the semiconductor module by controlling the switching losses during the switching state while providing power quality in the required limits and maintaining voltage stability, referred to as active thermal control. Sequence-based control is chosen in this study for its ability to deal with the system nonlinearities, control multiple constraints simultaneously with guaranteeing the system requirements and ensure the stability. The method is developed and the simulation is performed using MATLAB/Simulink software to validate the performance of the algorithm and tune the control parameters. The simulation results show that the proposed method can control the switching losses by influencing the switching sequence for a two-level three-phase active front end rectifier. For the validation, the influence of the proposed method on a two-level three-phase active rectifier is demonstrated experimentally by using Control Hardware-in-the-Loop (CHIL) setup. These will be tested utilizing the Texas Instrument (TI) C2000 XL LaunchPad controller and Opal-RT real-time simulator to perform CHIL experiments.
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Date Issued: 2019
Identifier: 2019_Fall_Ozkan_fsu_0071E_15544
Format: Thesis

Title: Energy Management System for Smart Buildings and Microgrids Using Sampling-Based Model Predictive Control (SBMPC) and Machine Learning.
Creator: Ospina, Juan Jose, Faruque, Md Omar, Ordóñez, Juan Carlos, Anubi, Olugbenga Moses, Foo, Simon Y., Florida State University, FAMU-FSU College of Engineering, Department of...
Show moreOspina, Juan Jose, Faruque, Md Omar, Ordóñez, Juan Carlos, Anubi, Olugbenga Moses, Foo, Simon Y., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: As the cost of renewable energy resources decreases and environmental concerns, such as global warming, arise, new ways of generating, storing, and using clean energy are being encouraged by governments and organizations around the world. Due to the growing energy demand, the modernization of the power grid has become an immediate priority that is leading to the decentralization of power systems, the creation of transactive energy markets, and the integration of distributed energy resources ...
Show moreAs the cost of renewable energy resources decreases and environmental concerns, such as global warming, arise, new ways of generating, storing, and using clean energy are being encouraged by governments and organizations around the world. Due to the growing energy demand, the modernization of the power grid has become an immediate priority that is leading to the decentralization of power systems, the creation of transactive energy markets, and the integration of distributed energy resources (DER). Traditionally, bulk power generation is based on a unidirectional structure, where electricity is generated on monolithic fossil fuel power plants and is then delivered to customers through different stages of transmission and distribution systems. This classical framework has many disadvantages, including, but not limited to, high inefficiencies and power losses in the system over lengthy transmission and distribution lines, a central point of failure of the system, and the emission of greenhouse gases that contribute to polluting our planet. That is why, progressively, governments and companies are starting to heavily invest in the development of new ways of integrating renewable power generation and DER systems into the modern power grid. The integration and control of these systems are considered essential problems that need to be tackled in order to build the future smart grid and advance universal electrification efforts. However, these systems are still not ready for a harmonious integration to the main electrical grid due to problems related to their intermittent nature and lack of proper control. Additionally, most of these systems still have a high price tag when compared to traditional power generation, and that is why their integration is not seen as a good investment for regular consumers and even large utility companies. Many researchers around the world are currently working on developing methods and frameworks that could allow the harmonious integration of renewable energy systems and other distributed energy resources with the main electrical grid. Nonetheless, since this problem does not have a trivial solution, sophisticated control methods and techniques need to be designed and developed to control DER systems and advance the decentralization of power. This dissertation is focused on the development of novel methods and algorithms, with particular emphasis on energy management applications that can facilitate the integration of DER systems to the modern power grid. This dissertation begins with an in-depth literature review of state-of-the-art energy management controllers designed to control available DERs in microgrids and buildings connected to modern distribution systems. Here, we aim to identify some of the key knowledge gaps present in this area and propose solutions designed to tackle these problems. The second chapter presents an overall review of microgrid systems and all the major components it is composed of. Additionally, it focuses on reviewing the state-of-the-art technologies currently being used and researched in the field of energy management of buildings and microgrids, with a detailed explanation of all the types of control and features these systems could include, like energy management and renewable generation forecasting. In this chapter, we explore some of the current solutions available for energy management systems and present the reason why our approach is being proposed as a cost-effective solution to the energy management problem. After this, the next chapters concentrate on explaining the fundamental theory behind the individual modules required by the proposed control method while proving its applicability in a real-world scenario. The modules developed can be described as follows: 1. A load and generation forecasting module based on a novel short-term PV power forecasting model and a neural network load forecasting model. 2. An energy management controller module based on Sampling-Based Model Predictive Control (SBMPC). The performance of this module is improved using models based on deep reinforcement learning. 3. A controller hardware-in-the-loop (CHIL) testbed designed to test the proposed model in a real-time environment. The development of the forecasting module is the main topic presented in the third chapter of this dissertation. This chapter focuses on exploring the theory behind the development of a novel short-term PV power generation forecasting architecture that significantly improves the performance of PV power forecasting by using a combination of the stationary wavelet transform (SWT), long-short term memory (LSTM) networks, and deep neural networks. The proposed forecasting model exhibits significant performance improvements in metrics such as forecast skill scores and the mean absolute percentage error (MAPE) when compared to state-of-the-art models used in short-term PV power forecasting applications. The fourth chapter of this dissertation is concerned with describing the theoretical background and concepts behind the proposed energy management solution. Here, we present an alternative graph-search formulation of the energy management problem and adapt Sampling-Based Model Predictive Control (SBMPC) to solve the formulated optimization problem. Moreover, chapter 5 considers the use of a deep reinforcement learning agent based on an asynchronous advantage actor-critic (A3C) model to enhance the performance of the formulated solution via learning a dynamic sampling process. Finally, chapter 6 focuses on the development of a real-time controller hardware-in-the-loop (CHIL) testbed designed to evaluate and test the proposed solution in a real-time simulated environment. In this chapter, interfacing modules between the external physical controller and the real-time system are developed using standard communication protocols such as TCP/IP and DNP3. In summary, the proposed solutions presented in this manuscript are aimed to improve methods related to the optimal control of DER systems under varying price schemes by leveraging the use of novel control and machine learning techniques. The main objective of this dissertation is to provide a detailed view of the theory behind the development of a proposed energy management solution that aims to minimize the operating cost for consumers and facilitates the integration of distributed energy resources (DER) into our modern power grid.
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Date Issued: 2019
Identifier: 2019_Fall_Ospina_fsu_0071E_15540
Format: Thesis

Title: Cryogenic Dielectric Behavior of Gases in Uniform and Weakly Non-Uniform Electric Fields.
Creator: Telikapalli, Srikar, Pamidi, Sastry V., Cheetham, Peter, Faruque, Md Omar, Anubi, Olugbenga Moses, Florida State University, FAMU-FSU College of Engineering, Department of...
Show moreTelikapalli, Srikar, Pamidi, Sastry V., Cheetham, Peter, Faruque, Md Omar, Anubi, Olugbenga Moses, Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Environmental preservation has now become paramount as natural resources are rapidly being consumed. A large part of the emissions rejected into the atmosphere comes from the transportation vehicles due to their combustion-based propulsion systems. This has created a paradigm shift towards the electrification of transport systems. All-electric ships and electric aircraft require high powered devices of few tens of MW. They also need devices with high power densities. Using medium voltage...
Show moreEnvironmental preservation has now become paramount as natural resources are rapidly being consumed. A large part of the emissions rejected into the atmosphere comes from the transportation vehicles due to their combustion-based propulsion systems. This has created a paradigm shift towards the electrification of transport systems. All-electric ships and electric aircraft require high powered devices of few tens of MW. They also need devices with high power densities. Using medium voltage helium gas-cooled superconducting power device technology in transport systems will provide the required power densities, both gravimetric and volumetric. One major challenge of operating cryogenic helium gas-cooled superconducting devices at medium voltage is the weak dielectric strength of helium gas. Over the past several years, the research team at Florida State University Center for Advanced Power Systems (FSU-CAPS) has been working on enhancing the dielectric strength of helium-based gas mixtures. It was discovered that the addition of a small mol% of stronger dielectric gas such as hydrogen or nitrogen to helium results in a significant improvement in the dielectric strength of the gas mixture. The research for this thesis continued the study of dielectric strength of gas mixtures with additional compositions using measurements of dielectric strength of gas mixtures at room temperatures and at cryogenic temperature of 77 K. The results show further enhancement of dielectric strength in some gas mixtures compared to the previous compositions both at 293 K and 77 K. The enhanced dielectric strength was expected in compositions with higher mole fractions of H2 and N2 compared to the compositions studied earlier. The study conducted for this thesis experimentally verified the predictions. The research team at FSU-CAPS has proposed, designed, and demonstrated a first of a kind gas insulated superconducting power cable (S-GIL) results. Breakdown measurements on the model cables of S-GIL cooled with helium gas mixtures revealed that the enhancements in the dielectric strength of gas mixtures did not fully translate to the enhanced performance of the S-GIL model cables. One of the suspected reasons for the observed discrepancy is the inherent non-uniform electric field in the SGIL cables. All the previous measurements of dielectric strength of gas mixtures were carried out in a uniform electric field. This research focused on the behavior of gases in uniform and weakly non-uniform electric fields at room temperatures and at 77 K to explain the discrepancy discussed earlier. A new experimental set up for measuring the breakdown strength of gas media in a weakly non-uniform electric field was established as part of the research for this thesis. The setup was used to measure the dielectric strength of pure helium and helium-based gas mixtures at room temperature and at 77 K at high pressures up to 2 MPa. Measurements of breakdown strength of helium-based gas mixtures at 293 K in a non-uniform electric field with a field efficiency factor 62.5% were conducted to match the field efficiency factors typically exist in the optimized S-GIL. The experimental results suggest that the breakdown strength in the non-uniform electric field relate to that of the uniform electric field by the field efficiency factor, η. This relationship was observed to hold good for both the 293 K and 77 K data. This observation expands our previously reported systematics of dielectric strength in uniform electric field to the non-uniform electric field conditions, which will expand our fundamental understanding of the dielectric behavior of gas media. Furthermore, the results give us a useful relationship between the dielectric strength data in uniform electric field and weakly non-uniform electric field, which will be useful in estimating the dielectric behavior of S-GIL power cables and other applications that use gases as dielectric media. The established relationship eliminates the need for costly experiments for measuring the dielectric strength at a specific operating temperature and pressure and in the required non-uniformity of the electric field.
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Date Issued: 2019
Identifier: 2019_Fall_Telikapalli_fsu_0071N_15582
Format: Thesis

Title: Optimization of Insulated Gate Bipolar Transistors Using an Adjoint Space Method.
Creator: Zhu, Chen, Andrei, Petru, Vanli, Omer Arda, Foo, Simon Y., Li, Hui, Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: A central problem in the power semiconductor industry is to design semiconductor devices with high breakdown voltage and low on-state resistance. This problem is usually addressed computationally by developing a physics-based model for the power device and adjusting the device structure until the required parameters (i.e. breakdown voltage and on-state resistance) are optimized. In the case of finite element models, the optimization of power devices requires computing the optimum value of the...
Show moreA central problem in the power semiconductor industry is to design semiconductor devices with high breakdown voltage and low on-state resistance. This problem is usually addressed computationally by developing a physics-based model for the power device and adjusting the device structure until the required parameters (i.e. breakdown voltage and on-state resistance) are optimized. In the case of finite element models, the optimization of power devices requires computing the optimum value of the doping concentration at each vertex of the finite element mesh, which is equivalent to solving an optimization problem with a large number of control parameters (usually over 105 parameters). This problem cannot be solved using traditional heuristic techniques because such techniques require many device simulations, which result in unpractically long computation times even on dedicated computer clusters. In this dissertation we develop a non-heuristic technique to optimize power semiconductor devices and apply this method to the optimization of Insulated Gate Bipolar Transistors (IGBTs) modeled by finite elements. The method is based on computing the doping sensitivity functions of the breakdown voltage and on-state resistance using an adjoint method that we developed specifically for this task, and it uses these functions in a gradient based optimization algorithm to compute the optimum doping profile inside the device. As numerical examples, we present two optimization cases. First, we optimize the doping profile of a standard IGBT structure in order to maximize the breakdown voltage while keeping the on-state resistance constant; then, we minimize the on-state resistance while keeping the breakdown voltage constant. In both cases, we show that the proposed method can be used successfully to the optimization of the doping profiles that maximizes the breakdown voltage of the IGBT.
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Date Issued: 2019
Identifier: 2019_Fall_Zhu_fsu_0071E_15524
Format: Thesis

Title: A High Voltage LLC DC-DC Converter with SiC Devices.
Creator: Wu, Ruoyu, Li, Yuan, Li, Hui, Anubi, Olugbenga Moses, Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: A 2kV high voltage LLC resonant DC to DC converter using silicon carbide (SiC) devices is proposed. The converter is applied for the medium voltage PV system to boost PV array terminal voltage and carry out maximum power point tracking (MPPT). The proposed LLC resonant converter consists of three main parts including full bridge, LLC resonant tank and high voltage transformer. Zero voltage switching (ZVS) are achieved among all power MOSFETs. Meanwhile, SiC MOSFETs are used to provide higher...
Show moreA 2kV high voltage LLC resonant DC to DC converter using silicon carbide (SiC) devices is proposed. The converter is applied for the medium voltage PV system to boost PV array terminal voltage and carry out maximum power point tracking (MPPT). The proposed LLC resonant converter consists of three main parts including full bridge, LLC resonant tank and high voltage transformer. Zero voltage switching (ZVS) are achieved among all power MOSFETs. Meanwhile, SiC MOSFETs are used to provide higher efficiency, which will increase the power density of the converter and highlight the advantage of soft switching. Besides, A wide input voltage of 300 V to 500 V is accommodated with a flexible voltage gain of the LLC resonant converter. In this thesis, the detailed design procedure is presented. And the principle of operation and the characteristics of the proposed converter circuit is analyzed and verified based on the simulation and experiment results.
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Date Issued: 2019
Identifier: 2019_Fall_WU_fsu_0071N_15594
Format: Thesis

Title: Design, Simulation and Fabrication of Multijunction Polymer and Hybrid Solar Cells.
Creator: Khanam, Jobeda Jamal, Foo, Simon Y., Meyer-Bäse, Anke, Andrei, Petru, Bernadin, Shonda, Yu, Zhibin, Florida State University, FAMU-FSU College of Engineering, Department of...
Show moreKhanam, Jobeda Jamal, Foo, Simon Y., Meyer-Bäse, Anke, Andrei, Petru, Bernadin, Shonda, Yu, Zhibin, Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: In recent years, organic solar cells (OSCs) have been attracting much attention due to the ease of processing, low cost, flexibility, and lightweight compared to the traditional inorganic solar cells. Although OSC looks promising, it has some significant limitations. One limitation is the low efficiencies of the OSCs compared to silicon and III-V compound solar cells, due to limited exciton generation when the light strike on it and low electron and hole mobility. Moreover, OSC has poor...
Show moreIn recent years, organic solar cells (OSCs) have been attracting much attention due to the ease of processing, low cost, flexibility, and lightweight compared to the traditional inorganic solar cells. Although OSC looks promising, it has some significant limitations. One limitation is the low efficiencies of the OSCs compared to silicon and III-V compound solar cells, due to limited exciton generation when the light strike on it and low electron and hole mobility. Moreover, OSC has poor stability and short lifetime, due to the degradation of the polymer/electrode interface. For improve the efficiency of PSC, several methods implemented such as annealing, device structure tuning, and active material modification, etc. Among them staking two or more organic junctions (BHJ/HJ) are called tandem structure is one of the most effective solutions. Also, the PV devices using a mixture of inorganic nanoparticle and conjugated polymers called hybrid solar cells (HSCs), has been gain popularity for absorbing near-infrared light. It is essential to tune the thickness of active layers used in tandem photovoltaic to optimize the device performance. Finding the optimum tandem structure using trial and error experiments is expensive and sometimes ineffective. Simulation is a more efficient tool to create the most suitable tandem device structure. The current-voltage (J-V) characteristics will be used to compare the results of simulation and experimental data. The transfer matrix method is implemented for optical modeling of an OSC and HSCs, which was inspired by McGehee Group MATLAB program. The program calculates optimal thicknesses active layers giving the best short circuit current (Jsc) value. It has here shown different multijunction polymer solar cell which can able to absorb sunlight beyond 1000nm. Then explained the high-efficiency hybrid (organic and inorganic) solar cell which can absorb the sunlight with wavelength beyond 2500nm. In this work, we present a novel multijunction polymer solar cell and hybrid solar cell designs. Approximately 12% efficiency obtained from multijunction polymer solar cell, and 20% efficiency from every two, three, and four junction hybrid solar cells, under one sun AM1.5 illumination. Based on the simulation results, we fabricated single-junction PbS Quantum Dot (QD) solar cell. The PbS quantum dots (QD) is a promising nanostructured material for solar cell. However, insufficient works have been done to explore the active layer thickness, stability improvement, the layer deposition techniques, and cost reduction for PbS QD solar cell. We addressed those issues of device fabrication and suggested their possible solutions. In our work, to get maximum current density from a PbS QD solar cell, we estimated optimized active layer thickness using MATLAB simulation. After that, we fabricated high performance and low-cost QD photovoltaic (PV)device with the simulated optimized active layer thickness. We implemented the low-cost device by using 10mg/ml PbS concentration. Here drop-cast layer deposition and spin coating methods were used and compared. We found that the device fabricated by the spin coating method is more efficient than the drop cast method. The spin-coated PbS QD solar cell produced 6.5% power conversion efficiency (PCE) at AM1.5 light spectrum. Besides, we observed, Cr (chromium) interfaces with the Ag (Cr- Ag) electrode can provide a high air-stable electrode.
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Date Issued: 2019
Identifier: 2019_Fall_khanam_fsu_0071E_15497
Format: Thesis

Title: A Predictive Model of Design Performance for Lithium-Ion Capacitors.
Creator: Moye, Davis George, Foo, Simon Y., Meyer-Bäse, Anke, Andrei, Petru, Roberts, Rodney G., Yu, Zhibin, Florida State University, FAMU-FSU College of Engineering, Department of...
Show moreMoye, Davis George, Foo, Simon Y., Meyer-Bäse, Anke, Andrei, Petru, Roberts, Rodney G., Yu, Zhibin, Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Recent years have seen developments in lithium-ion capacitor (LIC) technology. However, there has been scant work in mathematical models to predict the performance of LICs. Existing models have focused upon cell degradation over time or simple Randles circuits to describe laboratory work. Experimentalists have determined that LICs’ energy storage capabilities are inversely proportional to their charge or discharge (dis/charge) current. But this phenomenon is not well understood, a serious...
Show moreRecent years have seen developments in lithium-ion capacitor (LIC) technology. However, there has been scant work in mathematical models to predict the performance of LICs. Existing models have focused upon cell degradation over time or simple Randles circuits to describe laboratory work. Experimentalists have determined that LICs’ energy storage capabilities are inversely proportional to their charge or discharge (dis/charge) current. But this phenomenon is not well understood, a serious barrier to LIC market entry as designers struggle to predict the energy storage of LICs under design. This study begins with an experiment on applying lithium to LICs. Then it discusses a study on the cycle life of LICs. Earlier studies had found the degradation of LICs cycled at constant current but different temperatures can be described by an Arrhenius equation. This cycle life study found that when an LIC is cycled at a constant temperature but different cycle currents the results can also be described by an Arrhenius equation, which can be derived from the Arrhenius equation describing degradation as a function of current. The Butler-Volmer equation anticipates these results because it predicts direct proportionality between a LIC’s cycle current and temperature. The predictive model, which comprises the bulk of this research, began with electrochemical impedance spectroscopy experiments (EIS) on an LIC to build a Randles equivalent circuit model (ECM) describing the same LIC. This LIC was then charged at several constant powers, recording the stored energy. Using the Randles ECM, simulated LICs were charged at these same constant powers, yielding high fidelity at low power but significant error at high power. In order to solve this high power inaccuracy, all of the experimentally-derived values, except for the series resistance and Warburg resistance, were replaced by physics equations that would compute these values. The Butler-Volmer equation was manipulated to express dis/charge current in terms of temperature, which computed the Warburg capacitance and dis/charge transfer resistance, key elements in a Randles ECM. This change yielded an accurate energy computation, but not an accurate voltage computation. Furthermore, the temperature values computed by the Butler-Volmer equation were unrealistic and could not be reconciled mathematically. The next iteration of the study involved in situ temperature measurements of LICs during dis/charge cycles. These in situ measurements indicated that temperature change is only observed during low power dis/charges, and even then it is <1% of absolute temperature. This indicates that although the Butler-Volmer equation can express LIC temperature in terms of dis/charge current, temperature can be treated as a constant without much loss in model fidelity. Warburg impedance was observed to be computed in terms of temperature and is almost constant, like temperature. Series resistance negligibly affects voltage change or energy stored in an LIC. This is the first known physics-based model to predict an LIC’s energy storage as a function of its dis/charge current and constituent components. This model also explains the current-energy inverse relationship observed in LICs using a new derivation of the Butler-Volmer equation. This model may have significant commercial value for LIC designers in the future as it eliminates a significant barrier to market entry.
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Date Issued: 2019
Identifier: 2019_Fall_Moye_fsu_0071E_15490
Format: Thesis

Title: Impedance Measurement Techniques in Noisy Medium Voltage Power Hardware-in-the-Loop Environments.
Creator: Chauncey, Gunnar Luke, Li, Hui, Steurer, Michael, Yu, Ming, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: In Power Hardware-In-The-Loop (PHIL) simulations, it is important to understand the impedance characteristics of the system being tested. These impedances are used in the assessment of both the stability and the accuracy of the PHIL simulation experiment, as well as for stability analyses for the integration of the device under test (DUT) into the eventual system of deployment. When testing medium voltage systems in the megawatt power range, sensor noise stemming from the switching amplifiers...
Show moreIn Power Hardware-In-The-Loop (PHIL) simulations, it is important to understand the impedance characteristics of the system being tested. These impedances are used in the assessment of both the stability and the accuracy of the PHIL simulation experiment, as well as for stability analyses for the integration of the device under test (DUT) into the eventual system of deployment. When testing medium voltage systems in the megawatt power range, sensor noise stemming from the switching amplifiers can become quite an issue. This thesis evaluates four different impedance measurement techniques to find a reliable, accurate, and quick assessment over a wide frequency range in the noisy environments of medium voltage systems. (1) a single tone consisting of one sine wave at a single frequency, (2) a multitoned signal which is the sum of multiple sine waves, each at a unique frequency, (3) a frequency-swept sine wave, also known as a “chirp”, and (4) a pseudorandom binary sequence. Each of these signals are injected into the system while energized in order to measure the response, which is then processed for the impedance characteristics. Various tests are conducted to simulated systems with simulated sensor noise to determine the viability of each of the techniques. Once the techniques are determined to be appropriate signals for system characterization in noisy medium voltage systems, they will be applied to a simulated Multilevel Modular Converter (MMC) model. The data from the simulated model will then be verified with a hardware experimental verification test with the viable signals chosen.
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Date Issued: 2018
Identifier: 2018_Su_Chauncey_fsu_0071N_14782
Format: Thesis

Title: Object Detection Techniques Using Convolutional Neural Networks.
Creator: Panthula, Ganesh Anirudh, Foo, Simon Y., Harvey, Bruce A., Moss, Pedro L., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer...
Show morePanthula, Ganesh Anirudh, Foo, Simon Y., Harvey, Bruce A., Moss, Pedro L., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Object detection is an important part of the image processing system, especially for applications like Face detection, Visual search engine, counting and Aerial Image analysis. Hence the performance of object detectors plays an important role in the functioning of such systems. With the advancements in the Deep learning field, Convolutional Neural Networks (CNN) is now the state of the art in object detection and classification. In this thesis, we have investigated different object detection...
Show moreObject detection is an important part of the image processing system, especially for applications like Face detection, Visual search engine, counting and Aerial Image analysis. Hence the performance of object detectors plays an important role in the functioning of such systems. With the advancements in the Deep learning field, Convolutional Neural Networks (CNN) is now the state of the art in object detection and classification. In this thesis, we have investigated different object detection models and studied the chain of developments which has taken place from one model to the next, the improvements over the previous models are studied by comparing the model architecture, methods of extracting features and by the performance on different object detection and classification competitions. The thesis is divided into three parts, first, a few notable models developed before the deep learning era are studied, these models have hand-coded feature extractors. In the next part of the thesis, Convolutional Neural Networks, part of deep learning for object detection has been researched by understanding the basic Convolutional Neural Network architecture and then different ways to improve it. It is seen that the CNN object detectors use a base architecture, these architectures can be classified as basic and advanced. In the final part of the thesis, the Meta architectures, which are divided as region based and regression based models are presented in detail, with depictions of such implementations. These Meta architectures are based on the basic and advanced architectures studied in the previous sections. With a look at the hand coded features based object detectors in the beginning, this work ends with a comparison of the state-of-the-art models discussed in the Meta architecture section. In the end, the future scope of the object detectors and possible new applications are discussed. Keywords: Neural Networks, Convolutional Neural Networks, object detectors, Deep learning, regression based, region based
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Date Issued: 2018
Identifier: 2018_Su_Panthula_fsu_0071N_14802
Format: Thesis

Title: A New Two-Stage Game Framework for Power Demand Response Management in Smart Grids.
Creator: Fan, Huipu, Yu, Ming, Liu, Xiuwen, Tung, Leonard J., Andrei, Petru, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: Recently, the smart grid technologies have been developed rapidly recently, which an important component is the so called demand response management (DRM). With the help of a DRM program, a utility company can adjust the power demand and electricity price to reduce the cost of power generation and consumption. However, there are many problems in DRM need to be solved. For example, to solve the problem of optimizing a generator's power (GP), the conventional methods such as economic dispatch ...
Show moreRecently, the smart grid technologies have been developed rapidly recently, which an important component is the so called demand response management (DRM). With the help of a DRM program, a utility company can adjust the power demand and electricity price to reduce the cost of power generation and consumption. However, there are many problems in DRM need to be solved. For example, to solve the problem of optimizing a generator's power (GP), the conventional methods such as economic dispatch (EDP) may reduce the profit of the utility company. To solve the problem of optimizing a consumer's power (CP), the existing smart pricing strategies may reduce the long-term benefits of the customers. This dissertation aims to develop a two-stage game model to increase the profit of the utility company and while increase the long-term benefit of the customers. For solving the GP. It is critical for the power generator and utility company to allocate the power demand properly, but the profit for the utility company may be reduced. To solve the CP, it is difficult for the customers to achieve a long-term beneficial power-usage-pattern with myopic pricing strategies. The stability of the smart grid and the benefit of the customers may also be reduced due to the myopic pricing strategies. It is difficult for the utility company to use the existing methods (e.g., EDP) to order an optimal power demand from the power generators to earn the maximum profit. There are two issues that are needed to be solved in the GP. First, the weight function for the utility company and power generators in the GP is not established properly in the existing methods. For example, the value of the weight function for the utility company and power generators are usually the same in an EDP method. However, in a smart grid, the utility company has the privilege to demand the power while the power generators must follow the demand. Hence the value of weight function for the utility company should be greater than the one for the power generators in a GP. Second, the optimal demand for the utility company is most likely not the optimal generation for the generators. The imbalanced power will increase the generation cost significantly. It is also difficult for a utility company to maintain an efficient DRM for a long-time period by using the existing smart pricing strategies. Applying incentive is the major solution for the utility company to influence the power demand of a customer. However, the traditional pricing strategies are shortsightedly designed, by which the long-time efficiency for the DRM is reduced. For example, the trigger punishment strategy applies a punishing price to a customer for a long period when a non-cooperation behavior is detected. During the punishment period, the customer chooses its power consumption freely since the punishment will be applied anyway. Such selfish behaviors reduce the long-term efficiency for the DRM and the stability of the smart grid. In this dissertation, we propose a two-stage game model to solve the GP and CP to increase the long-term efficiency for the DRM, maintain the stability of the smart grid, and also increase the profit of the utility company. In the first stage, a Stackelberg game model is applied to solve the GP, in which the utility company is the leading player while the generators are the following players. We prove that the GP for the following players is a convex problem mathematically. The following players achieve the Nash equilibrium (NE) state by choosing the unique optimal generation. The leading player reacts with this unique generation to achieve the optimal profit. Both the leading and following players reach an agreement in the NE state, in which they have no motivation to deviate the optimal actions. A genetic algorithm is developed to obtain the optimal demand for the leading and following players. In addition, we introduce a power balance constraint to the leading and following players to avoid the cost caused by the imbalanced power. By applying the constraint, the generated power is equal to the demand all the time. The smart grid will not need to store the excessive power in the energy storage unit or send the power back to the power generators to keep them idling. The cost is avoided and the efficiency of the DRM is increased. In the second stage, a repeated game model is applied to solve the CP, in which the customers are the players. The strategy for the players is to minimize the individual power consumption of each customer. The utility function for the players is the cost of the customers. The objective for the players is to minimize the cost. In this work, we prove that the NE state exists for the repeated game. However, it has been shown that in the NE state, the players' myopic behaviors may reduce the benefits for the entire group of players. To avoid the loss, we use a genetic algorithm to find the Pareto-efficient solution for the players, in which no player can increase its benefit by reducing other players' benefit. We apply a Tit-for-Tat (TFT) smart pricing strategy to increase the punishment strength from the utility company. Once an irrational behavior from a player is detected, a punishment will be applied to the player for a short period of time. The player can choose to cooperate or not during the punishment period. Compared to the existing smart pricing strategies, the long-term benefit for the smart grid is increased by applying the TFT strategy to the customers. The numerical simulations in different scenarios are conducted to evaluate the performance of the proposed two-stage game framework by using MATLAB. All the parameters and constraints of the related components are from the Department of Energy's report and the Oasisui online database. Five power generators, one utility company, and one hundred customers have been used in the simulations. Compared with the existing solutions (e.g., EDP and gaming optimization), the cost in power consumption is reduced by 6% percent while the profit for power generation is increased by 8% percent in our test scenarios. With the help of the proposed model, we enhance the efficiency for the DRM. The peak-to-average ratio (PAR) of the power demand of our work is compared with the EDP method. The effect of the PAR is studied. The numerical results show that the proposed model has a similar PAR to that of the EDP method, which implies that the proposed model has no negative influence on the stability of the smart grid. The punishing effort of the TFT strategy is compared with the trigger strategy (TP) to study the punishment influence on the customers. The numerical results show that the customers who are applied with the TFT strategy are more willing to cooperate with the utility company. The impact of the power loss ratio and different types of customers is also simulated and analyzed. The simulation results show that the players with a greater transmission loss ratio are more willing to cooperate. The customers that are associated with a greater linear dissatisfaction coefficient are more concerned about the dissatisfaction cost. The customers with greater price-sensitive coefficients are more concerned about the consumption cost. In summary, compared to the existing solutions, the proposed two-stage game model improves the performance of the DRM while maintain the stability of the smart grid. We also discuss the future research issues in the related areas.
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Date Issued: 2018
Identifier: 2018_Su_Fan_fsu_0071E_14654
Format: Thesis

Title: Distributed Adaptive Droop Control for Power Management in DC Distribution Systems.
Creator: Perkins, Dallas, Edrington, Christopher S., Ordóñez, Juan Carlos, Foo, Simon Y., Moss, Pedro L., Florida State University, College of Engineering, Department of Electrical and...
Show morePerkins, Dallas, Edrington, Christopher S., Ordóñez, Juan Carlos, Foo, Simon Y., Moss, Pedro L., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: The current trend for naval destroyer-class ships is the move toward DC distribution systems as the next generation of ships is developed. The main motivation for using DC is to increase the power density of the ships to accommodate advanced weaponry such as the electromagnetic railgun. The distribution systems are also expected to be modular and plug-n-play in nature, leading toward a distributed control scheme to integrate the distributed sources and loads that could be online at any given...
Show moreThe current trend for naval destroyer-class ships is the move toward DC distribution systems as the next generation of ships is developed. The main motivation for using DC is to increase the power density of the ships to accommodate advanced weaponry such as the electromagnetic railgun. The distribution systems are also expected to be modular and plug-n-play in nature, leading toward a distributed control scheme to integrate the distributed sources and loads that could be online at any given time. One of the main performance requirements for the future power distribution systems is the ability to accurately share power among the distributed resources on the ship, while also maintaining the voltage stability of the distribution system, often referred to as power management. The primary candidate to accomplish the power management of the ship systems is droop control. Droop control has been extensively studied for terrestrial applications for sharing power between paralleled sources. Specifically, its application to DC microgrids is of interest since islanded microgrids have similar properties to ship systems. In these studies, it has been shown that conventional droop control is limited in its power sharing capabilities due to a tradeoff between the accuracy of the power sharing between devices and the regulation of the bus voltage. Secondary controllers have been proposed to modify the droop control scheme to alleviate these issues based on linear controllers or heuristic methods. However, accurate models for DC microgrids are difficult to derive for linear control design, and heuristic methods do not present an autonomous way to adjust the parameters of the controller. Therefore, adaptive control is proposed to adjust the droop controller’s parameters in an online fashion to find the optimal values based on the system conditions. Model reference adaptive control is chosen in this research for its ability to deal with system uncertainties and ensure stability. Specifically, combined model reference adaptive control is chosen for its improvements in transient response and robustness over the direct and indirect versions. The method is developed and simulated using MATLAB/Simulink to determine the performance of the algorithm. Additionally, a notional MVDC ship power system is developed in the same environment to provide a test system with various distributed sources and loads. A load profile is developed for the main system components such as propulsion, service loads, and the advanced weaponry to reflect a notional battle scenario. The algorithm is first tested in simulation, and then deployed to external distributed controllers to validate the performance of the power management scheme under hardware constraints and communication latency. The algorithm is also demonstrated in conjunction with a management layer for distributed energy storage modules throughout the ship system to further illustrate the real-world viability of the method.
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Date Issued: 2018
Identifier: 2018_Su_Perkins_fsu_0071E_14716
Format: Thesis

Title: Distributed Energy Management Utilizing Model Predictive Control for Naval Ship Applications.
Creator: Gonsoulin, David E., Clark, Jonathan E., Faruque, Md Omar, Pamidi, Sastry V., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: Future Naval vessels are looking to incorporate a new variety of electrical loads. These loads include rail guns, high power radars, electric propulsion drives, and lasers. These loads, especially the rail gun, can be classified as high-power ramp rate loads. Before now, these types of loads were not prevalent on naval vessels; therefore, generators were used throughout the ship to power a multitude of devices that did not require high-power ramp rates. Many of the generators had a specific...
Show moreFuture Naval vessels are looking to incorporate a new variety of electrical loads. These loads include rail guns, high power radars, electric propulsion drives, and lasers. These loads, especially the rail gun, can be classified as high-power ramp rate loads. Before now, these types of loads were not prevalent on naval vessels; therefore, generators were used throughout the ship to power a multitude of devices that did not require high-power ramp rates. Many of the generators had a specific purpose; there were no interconnections between generators. With these new types of loads, a power system that can accommodate these devices is needed. Integrated Power Systems (IPS) look to solve the high-power ramp rate issue as well as provide a multitude of benefits such as efficiency, resiliency, and reconfigurability. The generators, loads, energy storages, protections, etc. will all be located and connected within the IPS. The IPS can provide the foundation to achieve a multitude of benefits; however, the control system must be intelligent in order to realize the IPS’ full potential. Part of the control problem is how to manage sources and loads to ensure load demand is met. In terrestrial systems, the near infinite bus takes care of changes in load demand. In a microgrid, such as those found on ships, a large change in load demand, such as those seen by high-power ramp rate loads, can have adverse effects on the power system and devices connected to the power system. The control must coordinate the sources and/or loads to ensure load demand is met with minimal impact to the system. In this dissertation, the beginnings of a distributed Energy Management control layer are shown. The control layer looks to assist in realizing the IPS’ full potential. This is done by providing a distributed type of control to fortify the resiliency and reliability, ensuring load demand is met, and certifying the energy storages state of charge is maintained to ensure an ever-ready presence. This control layer aims to meet load demand, ensure device constraints (power ratings, ramp rate limitations, etc.) are not exceeded, and maintain the energy storages desired state of charge. The control objective is met through a combined approach of a distributed spinning reserve algorithm and distributed MPC. The distributed MPC utilizes the distributed optimization technique called the Alternating Direction Method of Multipliers (ADMM).
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Date Issued: 2018
Identifier: 2018_Su_Gonsoulin_fsu_0071E_14741
Format: Thesis

Title: Design and Implementing Multipurpose Sensor Network for Smart City Monitoring.
Creator: Cai, Donglin, Arghandeh, Reza, Pamidi, Sastry V., Foo, Simon Y., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: Weather and Air quality monitoring are very important aspects of smart city management. As population increase in the cities, the emission of pollutants includes Carbone Monoxide, Nitrogen Dioxide, Ozone and the Particulate matter will increase which will cause health and environmental issue. This paper is about developing a low-cost Urban sensors box based on Internet of Things. The Urban box is equipped with 4G/3G wireless communication which allows the wide range of mobility around the...
Show moreWeather and Air quality monitoring are very important aspects of smart city management. As population increase in the cities, the emission of pollutants includes Carbone Monoxide, Nitrogen Dioxide, Ozone and the Particulate matter will increase which will cause health and environmental issue. This paper is about developing a low-cost Urban sensors box based on Internet of Things. The Urban box is equipped with 4G/3G wireless communication which allows the wide range of mobility around the city. The Urban Sensor box is a collaborative work to monitor real-time data of the city’s environment, infrastructure, and activities. All these data will be provided to understand the interconnected behavior of different tangible networks of the urban environment.
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Date Issued: 2018
Identifier: 2018_Su_CAI_fsu_0071N_14789
Format: Thesis

Title: Sensor Fault Detection and Isolation in Power Systems.
Creator: Yang, Huawei, Edrington, Christopher S., Ordóñez, Juan Carlos, Moss, Pedro L., Foo, Simon Y., Florida State University, College of Engineering, Department of Electrical and...
Show moreYang, Huawei, Edrington, Christopher S., Ordóñez, Juan Carlos, Moss, Pedro L., Foo, Simon Y., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: In large-scale power systems, the integration of intelligent monitoring system increases the system resiliency and the control robustness. For example, sensor monitoring allows to automatically supervise the health of sensors and detect sensor failures without relying on hardware redundancy, and hence, it will further reduce the cost of monitoring systems in power systems. Sensor failure is critical in smart grids, where controllers rely on healthy measurements from different sensors to...
Show moreIn large-scale power systems, the integration of intelligent monitoring system increases the system resiliency and the control robustness. For example, sensor monitoring allows to automatically supervise the health of sensors and detect sensor failures without relying on hardware redundancy, and hence, it will further reduce the cost of monitoring systems in power systems. Sensor failure is critical in smart grids, where controllers rely on healthy measurements from different sensors to determine all kinds of operations. Current literature review shows that most of the researchers focus on control and management side of smart grids, assuming the information control centers or agencies get from sensors is accurate. However, when sensor failure happens, missing data and/or bad data can flow into control and management systems, which may lead to potential malfunction or even power system failures. This brings the need for Sensor Fault Detection and Isolation (SFDI), to eliminate this potential threat. The integration of the SFDI into monitoring systems will allow avoiding the contingencies due to fault data, and therefore increases the system resiliency and the control robustness. Hardware redundancy is the common solution for SFDI. By placing multiple sensors in the same position, the control center can then rely on redundant sensors when one is broken or inaccurate. Apparently, this method will increase the cost significantly when applying to large power systems. Analytical redundancy, on the contrary, a quantitative method built from power system models, is a more promising solution. It does not necessarily require hardware redundancy and hence can lower the cost. With an appropriate number of sensors placed in strategic locations, the algorithm can then automatically detect sensor failures without the need of extra redundant sensors. Furthermore, SFDI together with intelligent sensor optimization and placement will also facilitate the transfer of conventional central grid control to distributed decision making agencies with minimum computation and communication burden for each branch, and thus, it will enhance the system performance and resiliency. In this dissertation, a comprehensive review over the state-of-the-art FDI methodologies is given at first, then a proposed algorithm to determine the optimal location of computation agents is introduced, which serves as a guide for the SFDI algorithm implementation explained right after. The results of the algorithms indicated promising application in power system monitoring.
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Date Issued: 2018
Identifier: 2018_Su_Yang_fsu_0071E_14730
Format: Thesis

Title: Intelligent Energy and Operation Management of AC, DC and Hybrid Microgrids Based on Evolutionary Techniques.
Creator: Papari, Behnaz, Edrington, Christopher S., Clark, Jonathan E., Pamidi, Sastry V., Moss, Pedro L., Florida State University, College of Engineering, Department of Electrical and...
Show morePapari, Behnaz, Edrington, Christopher S., Clark, Jonathan E., Pamidi, Sastry V., Moss, Pedro L., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Intelligent energy management systems (EMSs) play pivotal roles for microgrids (MGs). The integration of distributed generators (DGs), energy storage devices (ESDs), electrical vehicles (EVs), and flexible loads in a large-scale system of interconnected MGs needs a local management and control platforms to avoid probable integration issues. Most of the small scale aforementioned components are operated in low voltage (LV) power networks which require optimal strategies to achieve sufficient...
Show moreIntelligent energy management systems (EMSs) play pivotal roles for microgrids (MGs). The integration of distributed generators (DGs), energy storage devices (ESDs), electrical vehicles (EVs), and flexible loads in a large-scale system of interconnected MGs needs a local management and control platforms to avoid probable integration issues. Most of the small scale aforementioned components are operated in low voltage (LV) power networks which require optimal strategies to achieve sufficient performance to operate interconnected to other MGs and upstream networks. Thus, an active energy management strategy is required for off and on grid modes of terrestrial and shipboard MGs to satisfy all demands and minimize unwanted outcomes. Due to the high penetration of renewable energy sources (RESs) and their output fluctuations in MGs, stochastic analysis besides deterministic should be considered to reduce the uncertainty effects of RESs based on their probabilistic nature. Robust EMSs are needed to diminish prediction errors and improve the reliability of power supplies in hybrid and interconnected MGs. Nevertheless, qualified approach to fulfill EMS for LV MGs in the large-scale will be challenging in both grid operation modes. Optimization modules into tertiary management layer have considered as a potential solution in order to actualize control strategy of the terrestrial or ship MGs with different types of practical constraints. However, each of these methods not only yield benefits but also bring new challenges related to their shortage. Different approaches have been considered to fulfill the EMS requirements of MGs. A large amount of literature focuses on the management strategy of MG in an off-line manner rather than multiple MGs which interact with each other and an upstream network in an on-line manner. In addition, the most commonly used optimization modules in EMSs do not meet the computational burden and convergence capability trade-off required for real-time applications. This report proposes a heuristic optimization approach for distributed control and management of hybrid MGs for real-time requirements. The Crow Search Algorithm (CSA) offers a superior method to move traditional non-linear optimization approaches since its fewer control parameters permit a rapid response compared to other search approaches. Moreover, a distributed fashion CSA (DCSA) is implemented to fulfill linear and non-linear solver requirements of real-time EMSs for hybrid power distribution system.
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Date Issued: 2018
Identifier: 2018_Sp_Papari_fsu_0071E_14436
Format: Thesis

Title: Combined Electrical and Thermal Models for Integrated Cryogenic Systems of Multiple Superconducting Power Devices.
Creator: Satyanarayana, Sharath R. (Sharath Raghav), Pamidi, Sastry V., Foo, Simon Y., Bernadin, Shonda, Florida State University, College of Engineering, Department of Electrical and...
Show moreSatyanarayana, Sharath R. (Sharath Raghav), Pamidi, Sastry V., Foo, Simon Y., Bernadin, Shonda, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: High Temperature Superconducting (HTS) technology is a potential option for applications that require high power densities for lightweight and compact solutions for transportation systems such as electric aircrafts and all-electric Navy ships. Several individual HTS power devices have been successfully demonstrated for these systems. However, the real benefit lies in providing the system level design flexibility and operational advantages with an integrated cryogenic system. A centralized...
Show moreHigh Temperature Superconducting (HTS) technology is a potential option for applications that require high power densities for lightweight and compact solutions for transportation systems such as electric aircrafts and all-electric Navy ships. Several individual HTS power devices have been successfully demonstrated for these systems. However, the real benefit lies in providing the system level design flexibility and operational advantages with an integrated cryogenic system. A centralized cryogenic cooling technology is being explored to serve multiple HTS devices in a closed loop system. This provides high efficiency and permits directing the cooling power to where it is needed depending on the mission at hand which provides operational flexibility. Design optimization, risk mitigation and the operational characteristics under various conditions need to be studied to increase the confidence level in HTS technology. Development of simpler and cost-efficient cryogenic systems are essential to make HTS systems attractive. Detailed electrical and cryogenic thermal models of the devices are also necessary to understand the of risks in HTS power systems and to devise mitigation techniques for all the potential failure modes. As the thermal and electrical characteristics of HTS devices are intertwined, coupled thermal and electrical models are necessary to perform system level studies. To enable versatile and fast models, the thermal network method is introduced for cryogenic systems. The effectiveness of the modelling technology was demonstrated using case studies of multiple HTS devices in a closed loop cryogenic helium circulation system connected in different configurations to access the relative merits of each configuration. Studies of transient behavior of HTS systems are also important to understand the response of a large HTS system after one of the cryogenic cooling components fails. These studies are essential to understand the risks and potential options in the design or in operations to mitigate some of the risks. Thermal network models developed in this study are also useful to study the temperature evolution along the whole system as a function of time after a component fails. The models are useful in exploring the design options to extend the time of operation of a device such as a HTS cable after the failure of the cryogenic system.
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Date Issued: 2018
Identifier: 2018_Su_Satyanarayana_fsu_0071N_14787
Format: Thesis

Title: Application and Analysis of the Extended Lawrence Teleoperation Architecture to Power Hardware-in-the-Loop Simulation.
Creator: Langston, James, Edrington, Christopher S., Vanli, Omer Arda, Steurer, Michael, Roberts, Rodney G., Faruque, Md Omar, Florida State University, College of Engineering,...
Show moreLangston, James, Edrington, Christopher S., Vanli, Omer Arda, Steurer, Michael, Roberts, Rodney G., Faruque, Md Omar, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Power hardware-in-the-loop (PHIL) simulation is a technique whereby actual power hardware is interfaced to a virtual surrounding system through PHIL interfaces making use of power amplifiers and/or actuators. PHIL simulation is often an attractive approach for early integration testing of devices, allowing testing with unrealized systems with substantial flexibility. However, while PHIL simulation offers a number of potential benefits, there are also a number of associated challenges and...
Show morePower hardware-in-the-loop (PHIL) simulation is a technique whereby actual power hardware is interfaced to a virtual surrounding system through PHIL interfaces making use of power amplifiers and/or actuators. PHIL simulation is often an attractive approach for early integration testing of devices, allowing testing with unrealized systems with substantial flexibility. However, while PHIL simulation offers a number of potential benefits, there are also a number of associated challenges and limitations stemming from the non-ideal aspects of the PHIL interface. These can affect the accuracy of the experiments and, in some cases, lead to instabilities. Consequently, accuracy, stability, and sensitivity to disturbances are some of the most important considerations in the analysis and design of PHIL simulation experiments, and the development of PHIL interface algorithms (IA) and augmentations for improvements in these areas is the subject of active research. Another area of research sharing some common attributes with PHIL simulation is the field of robotic bilateral teleoperation systems. While there are some distinctions and differences in characteristics between the two fields, much of the literature is also focused on the development of algorithms and techniques for coupling objects. A number of disparate algorithms and augmentations have also been proposed in the teleoperation literature, some of which are fundamentally very similar to those applied in PHIL simulation. While some of the teleoperation methods may have limited applicability in PHIL experiments, others have substantial relevance and may lend themselves to improvements in the PHIL application area. This work focuses on the application and analysis of a teleoperation framework in the context of PHIL simulation. The extended Lawrence Architecture (ELA) is a framework unifying and describing a large set of teleoperation interfacing algorithms. This work focuses on the application and analysis of the ELA to PHIL simulation. This includes the expression of existing PHIL IAs in the context of the ELA, derivation of relevant transfer functions and metrics for assessment of performance, the exploration of the implications of the transparency requirements, and the exploration of new IAs supported by the ELA which may be well suited to the particular characteristics of PHIL simulation.
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Date Issued: 2018
Identifier: 2018_Sp_Langston_fsu_0071E_14321
Format: Thesis

Title: Intelligent Transport System and Wireless Communication Technology Overview for Safety in Connected Vehicles.
Creator: Raj, Jayesh, Harvey, Bruce A., Foo, Simon Y., Bernadin, Shonda, Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: Vehicular communication network consists of different wireless communication technologies working in conjunction with each other. These different wireless communication technologies have different technical parameters. Wireless communication technology includes Dedicated Short-Range Communication, WiFi, WiMAX etc. depending upon their network range, data bit transfer rate, safe effective maximum intended communication range, modulation technique adopted and many more, are deployed for...
Show moreVehicular communication network consists of different wireless communication technologies working in conjunction with each other. These different wireless communication technologies have different technical parameters. Wireless communication technology includes Dedicated Short-Range Communication, WiFi, WiMAX etc. depending upon their network range, data bit transfer rate, safe effective maximum intended communication range, modulation technique adopted and many more, are deployed for specific safety application. The main objective of Intelligent Transport System (ITS) is Safety. Under safety application there are many objectives including safe approach to the intersection, pre and post-crash warning, total loss control correction etc. these safety applications require specific parameter of communication technology i.e. for safe intersection approach data bit rate need not to be high and other safety application seeks different parameter. It is obvious that no single wireless communication technology could fulfill all the specifics of communication technology and objective of ITS. In this research important wireless communication discussed. Their pros and cons are summarized in the vehicular environment. In order to show the importance of wireless communication technology in Vehicular network, one among many safety applications is simulated. In the simulation, safe approach to unsignalized intersection is simulated. Simulation is performed on VISSIM software developed by PTV group, Germany. Simulation is based on Nakagami Wireless probabilistic model under relaxed radio condition (no interferences) and finally conclusion is made.
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Date Issued: 2018
Identifier: 2018_Fall_RAJ_fsu_0071N_14945
Format: Thesis

Title: Current Control Strategies for Three-Phase Paralleled SiC Inverters.
Creator: Wang, Lu, Li, Hui, Clark, Jonathan E., Lipo, T. A., Steurer, Michael, Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: With more renewable energy integrated into the existing power consumption, power electronics play an important part to convert and control the power. Power inverters employ power semiconductors to converter DC into AC, which is an essential part in the renewable energy utilization. The paralleled transformer-less inverters are well adopted in the industry for large capacity grid-tie application. Compared with the centralized inverter, inverters in parallel can offer higher power rating,...
Show moreWith more renewable energy integrated into the existing power consumption, power electronics play an important part to convert and control the power. Power inverters employ power semiconductors to converter DC into AC, which is an essential part in the renewable energy utilization. The paralleled transformer-less inverters are well adopted in the industry for large capacity grid-tie application. Compared with the centralized inverter, inverters in parallel can offer higher power rating, higher reliability, and lower grid-side current harmonics. Transformers are commonly used in the grid-tie system to provide galvanic isolation and voltage ratio transformations. Eliminating transformers will be a great benefit to further improve the system efficiency, reduce the size and weight. However, removal of the transformer would result in ground leakage current between the DC input side and the grid ground. The emerging wide band gap (WBG) devices are bringing significant opportunities for inverters towards higher efficiency and higher power density, due to their substantial switching loss reduction over Si devices. Silicon carbide (SiC) adoption also brings new control challenges to the three-phase paralleled transformer-less inverters. The voltage slew rate can be as high as dozens or hundreds of volts per nanosecond and the harmonic frequency related with the turning-on and turning-off of the devices may be up to several hundreds of mega-hertz, these high dv/dt and di/dt can generate high frequency EMI noise that propagates to the whole system including the power stage and control circuits, and raise the issue of increased electromagnetic interference (EMI). With high switching frequency, it is more difficult to control the circulating current among paralleled inverters. The conventional carrier synchronization method cannot be applied due to the impact of communication and sample delay. Limited controller resource also prevents sophisticated control algorithms. In this research, a five-level T-type (5LT2) PV inverter paralleled through inter-cell transformer (ICT) is presented to elaborate the challenges and demonstrate the advantages in three-phase SiC inverter. There are three key current in the 5LT2 PV inverter: circulating current, grid current, and ground leakage current. Circulating current is suppressed by the ICT and further controlled by a current controller. With increased switching frequency and multilevel topology, it is possible for a SiC device based grid connected converter to achieve filter-less function and utilize the grid impedance for its switching harmonic attenuation. Analysis shows that the conventional control method with instantaneous grid voltage feedforward (IGVF) will significantly limit the bandwidth or stability margin of a filter-less grid-connected inverter, thus make the inverter sensitive to grid disturbance. Two proposed grid voltage feedforward control methods, which require little additional computation resources, are presented to suppress the grid voltage disturbance. The increased switching efficiency is beneficial to the high frequency (HF) ground leakage current suppression, since the common mode (CM) choke can be much smaller. The 5LT2 inverter has a significant common mode voltage (CMV) reduction compared to that of a 3-level T-type (3LT2) inverter. However, the low frequency (LF) ground leakage current caused by neutral point (NP) voltage oscillation becomes a new issue in larger power rating multi-level inverters. A LF CMV compensation method is proposed to suppress the LF CMV. In this research, a control system is developed for a 60 kW three-phase paralleled transformer-less filter-less SiC PV inverter, which achieves a power density of 27 W/in3 and 3 kW/kg with nature convection, and measured peak efficiency of 99.2%.
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Date Issued: 2018
Identifier: 2019_Spring_Wang_fsu_0071E_14943
Format: Thesis

Title: Speaker-Dependent Acoustic Emotion Recognition for Vehicle-Centric Applications.
Creator: Udhan, Tejal, Bernadin, Shonda, Sobanjo, John Olusegun, Foo, Simon Y., Harvey, Bruce A., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and...
Show moreUdhan, Tejal, Bernadin, Shonda, Sobanjo, John Olusegun, Foo, Simon Y., Harvey, Bruce A., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Speech is the most natural and fastest method of communication between humans. This fact compelled researchers to study acoustic signals as a fast and efficient means of interaction between humans and machines. For authentic human-machine interaction, the method requires that the machines should have the sufficient intelligence to recognize human voices and their emotional state. It is well-known that the emotional state of human drivers highly influences his/her driving performance. For...
Show moreSpeech is the most natural and fastest method of communication between humans. This fact compelled researchers to study acoustic signals as a fast and efficient means of interaction between humans and machines. For authentic human-machine interaction, the method requires that the machines should have the sufficient intelligence to recognize human voices and their emotional state. It is well-known that the emotional state of human drivers highly influences his/her driving performance. For example, there are many reports that describe road-rage incidents where drivers become emotionally enraged due to the actions of another driver. This anger may lead to a high-speed chase, tailgating, and sometimes even death due to a traffic crash or physical contact. If a car is ‘intelligent-enough’ to respond to a driver’s emotional state, it may be able to thwart negative outcomes of road-rage incidents. Speech emotion recognition, extracting the emotional state of speakers from acoustic data, plays an important role in enabling machines to be ‘intelligent’. Speech emotion recognition is an emerging field and presents many challenges. The set of most powerful features which can distinguish different emotions is not defined; hence, the selection of features is a critical task. Acoustic variability presented by numerous speech properties, such as length and complexity of human speech utterance, speaker’s gender, speaking styles and rate of speech, directly affects the most common speech features; thereby affecting the system performance. Most of the researchers used statistical approaches to recognize human speech; however statistical methods are complex and need more computational time. Moreover, emotion recognition being the developing field, researchers are exploring facial, gestural and acoustical features for emotion recognition. However, for vehicle-centric applications, audio and speech processing may provide better noninvasive and less distracting solutions than other interactive in-vehicle infotainment systems. Hence, acoustic feature extraction for emotion recognition in human drivers is a preferred design choice of this research. The goal of this research is to develop an optimal feature extraction algorithm for emotion recognition of four most common emotions (anger, happy, sad and no emotion). In this dissertation, six acoustic features are studied using decision-tree based algorithms to recognize speech-based human emotions and reduce the complexity of the system. The speech features used are pitch, intensity, frequency formants, jitter, shimmer and zero crossing rate. Pitch and intensity are qualitative voice feature, frequency formants and jitter provide the spectral features and zero-crossing rate and shimmer suffice as temporal features of human acoustical speech. The combination of different types of speech features is utilized to increase the accuracy of system. The decision tree-based algorithms are designed in MATLAB and are calculated using confidentiality-interval for each feature. For acoustic data visualization, PRAAT software is used. The system is designed for speaker-dependent emotion recognition since the accuracy of system is more as the utilized features are qualitative voice features; which are best-suited for emotion recognition. Data from two males and two females is analyzed for this dissertation. For the actual realization of system, noise analysis is performed using 5dB, and 15 dB signal-to-noise ratio levels. These are minimum and maximum noise levels experienced while driving on a freeway and parking lot. This dissertation is composed of five chapters. Chapter 1 presents the mechanism of human speech production and human emotions in speech. It comprises of various emotions and importance of acoustic signal for emotion recognition. Chapter 2 includes different local and global acoustic features, existing methods of speech recognition and emotion recognition and discusses the weaknesses of existing speech recognition systems for acoustical emotion recognition using various acoustic features and analysis algorithms. Chapter 3 outlines the proposed solution for acoustic emotion recognition using decision-tree based algorithm. It includes a description of each acoustical feature, data preparation techniques, data analysis methods, and algorithm design. Chapter 4 consists of results, discussion and comparison of proposed algorithm with state-of-the-art acoustic emotion recognition algorithms. Finally, conclusion, limitations and future work is discussed in chapter 5.
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Date Issued: 2018
Identifier: 2019_Spring_Udhan_fsu_0071E_14833
Format: Thesis

Title: Security Evaluation of Tree Parity Re-Keying Machine Implementations Utilizing Side-Channel Emissions.
Creator: Martinez Padilla, Jonathan E., Meyer-Baese, U., Meyer-Bäse, Anke, Foo, Simon Y., Yu, Ming, Florida State University, FAMU-FSU College of Engineering, Department of Electrical...
Show moreMartinez Padilla, Jonathan E., Meyer-Baese, U., Meyer-Bäse, Anke, Foo, Simon Y., Yu, Ming, Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: In this work, Side-Channel Attacks (SCAs) are considered as a security metric for the implementation of hybrid cryptosystems utilizing the neural network-based Tree Parity Re-keying Machines (TPM). A virtual study is presented within the MATLAB environment that explores various scenarios in which the TPM may be compromised. Performance metrics are evaluated to model possible embedded system implementations. A new algorithm is proposed and coined as Man-in-the-Middle Power Analysis (MIMPA) as...
Show moreIn this work, Side-Channel Attacks (SCAs) are considered as a security metric for the implementation of hybrid cryptosystems utilizing the neural network-based Tree Parity Re-keying Machines (TPM). A virtual study is presented within the MATLAB environment that explores various scenarios in which the TPM may be compromised. Performance metrics are evaluated to model possible embedded system implementations. A new algorithm is proposed and coined as Man-in-the-Middle Power Analysis (MIMPA) as a means to copy the TPM's generated keys. It is shown how the algorithm can identify vulnerabilities in the physical device in which the cryptosystem is implemented by using its power emissions. Finally, a machine learning approach is used to identify the capabilities of neural networks to recognize properties of keys produced in the TPM as they are transferred to an encryption algorithm. The results show that physical exploits of TPM implementations in embedded systems can be identified and accounted for before a final release. The experiments and data acquisition is demonstrated with an implementation of a TPM-hybrid cryptosystem in an AVR microcontroller. Additionally, obfuscation methods are explored in the form of control transformations. A tool is created utilizing FLEX and GCC to add opaque predicates into VHDL source code. The study incorporates the transformations into concurrent and sequential statements. A trade-off between cost and potency is seen in concurrent statements, while no cost is used in sequential statements all while retaining its original behavior.
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Date Issued: 2018
Identifier: 2018_Sp_MartinezPadilla_fsu_0071E_14442
Format: Thesis

Title: A Coordinated Voltage Control Technique for Distribution Systems with PV.
Creator: Zhang, Ziheng, Faruque, Md Omar, Foo, Simon Y., Pamidi, Sastry V., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: The future grid will combine both smart distribution network and distributed energy resources (DER) ensures it is reliable to do operations and increase the power quality. In the recent years, along with the traditional voltage regulators such as capacitor banks and tap changer transformers, power and voltage control based on DER method is widely proposed to cope with the overvoltage and undervoltage issues that causes by large penetration of distributed generation( DG). Moreover, with the...
Show moreThe future grid will combine both smart distribution network and distributed energy resources (DER) ensures it is reliable to do operations and increase the power quality. In the recent years, along with the traditional voltage regulators such as capacitor banks and tap changer transformers, power and voltage control based on DER method is widely proposed to cope with the overvoltage and undervoltage issues that causes by large penetration of distributed generation( DG). Moreover, with the application of advanced communication technology, some communication methods are applied on the voltage control in order to make the system coordinated. This thesis explores the area of decentralized control method to have a better understanding and knowledge of power system and its control. This is accomplished by designing a power system model and implement decentralized voltage control on it. The work starts with categorizing recent publications on coordinated voltage, summarizes way they modeled and built the systems, how they decoupled the systems and categorized the solution methods. Then this thesis proposes a novel coordinated voltage control technique designed to regulate the voltage along a distribution network by using zonal control of multiple PVs. The proposed strategy is tested using the IEEE 34 bus system in both offline and a controller hardware-in-the-loop (CHIL) real-time implementations. Data loss and communication latency scenarios are also performed with the objective of determining the overall behavior of the proposed controller. The outcome and aim of this work is expected to build real-time control models which can be applied on the real project
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Date Issued: 2018
Identifier: 2018_Fall_Zhang_fsu_0071N_14849
Format: Thesis

Title: Investigation of Energy Density Limitation for Lithium Sulfur Batteries.
Creator: Shen, Chao, Zheng, Jianping, Zhang, Mei, Andrei, Petru, Moss, Pedro L., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: Conventional lithium ion batteries (LIBs) have dominated the portable electronic devices market for more than thirty years. However, as the energy density of LIBs is approaching their theoretical limits, an alternative battery chemistry to transform the current energy landscape is currently highly needed. Rechargeable lithium-sulfur (Li-S) batteries with a theoretical specific energy as high as 2,500 Wh kg-1, are among the most promising high-energy-density electrochemical devices for future...
Show moreConventional lithium ion batteries (LIBs) have dominated the portable electronic devices market for more than thirty years. However, as the energy density of LIBs is approaching their theoretical limits, an alternative battery chemistry to transform the current energy landscape is currently highly needed. Rechargeable lithium-sulfur (Li-S) batteries with a theoretical specific energy as high as 2,500 Wh kg-1, are among the most promising high-energy-density electrochemical devices for future energy storage applications. However, the delivery of their high energy density is extremely challenging especially at a lean electrolyte condition. This dissertation is mainly focused on the investigation of energy density limitation of Li-S batteries and special attention is given to the battery performance at a lean electrolyte condition. We first investigated the effect of lithium polysulfide (LiPS) solubility on cell capacity and discovered that at low electrolyte/sulfur (E/S) ratios, the finite solubility of LiPS could induce their solid precipitation and become a capacity limitation for Li-S batteries. Next, to avoid the solubility limitation encountered on the upper plateau of the discharge, we used solid-state Li2S4 as the cathode active material to construct a new type of Li-Li2S4 battery, which exhibits enhanced performance compared to conventional Li-S battery at low E/S ratios. To obtain a more complete understanding of the growth mechanism of Li2S for enhanced discharge capacity in lower plateau, next we utilize a polished graphite as the standard cathode material to observe Li2S morphology evolution and cell impedance evolution during the discharge process. The combined experimental results with theoretical modeling sheds light upon the understanding and controlling of Li2S deposition process in Li-S batteries. In addition, we have conducted a focused study on the static stability, i.e., the self-discharge behaviors, of Li-S batteries at different E/S ratios. We found a strong dependence of the self-discharge rate on the depth of discharge at which the resting takes place and on the electrolyte/sulfur ratio. This relation is analyzed in detail showing that one should pay special attention to the state-of-charge during self-discharge and other operational conditions in order to improve the cyclability and capacity of Li-S batteries.
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Date Issued: 2018
Identifier: 2018_Fall_Shen_fsu_0071E_14894
Format: Thesis

Title: Hirschman Transform Applications in Compressive Sensing.
Creator: Xi, Peng, DeBrunner, Victor E., Gallivan, Kyle A., Harvey, Bruce A., DeBrunner, Linda S., Roberts, Rodney G., Florida State University, College of Engineering, Department of...
Show moreXi, Peng, DeBrunner, Victor E., Gallivan, Kyle A., Harvey, Bruce A., DeBrunner, Linda S., Roberts, Rodney G., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: The CS technology has attracted considerable attention because it can surpass the traditional limit of Nyquist sampling theory. Rather than sampling a signal at a high frequency and then compressing it, the CS senses the target signal in a compressed format directly. However, the great sampling improvement results in the increased complexity in decoding. The optimization of sensing structure never stops to simplify the decoding procedure as much as possible. Unlike the Heisenberg-Weyl measure...
Show moreThe CS technology has attracted considerable attention because it can surpass the traditional limit of Nyquist sampling theory. Rather than sampling a signal at a high frequency and then compressing it, the CS senses the target signal in a compressed format directly. However, the great sampling improvement results in the increased complexity in decoding. The optimization of sensing structure never stops to simplify the decoding procedure as much as possible. Unlike the Heisenberg-Weyl measure, the Hirschman notion of joint uncertainty is based on entropy rather than energy. The Discrete Hirschman Transform (DHT) has been proved to be superior in complexity reduction and high resolution to the traditional Discrete Fourier Transform in many aspects such as fast filtering, spectrum estimation, and image identification. In this dissertation, I implement a new deterministic compressive sensing system based on DHT with four contributions: (1) apply Weyl's sum character estimation to the DHT matrices to develop a new deterministic sensing structure (2) theoretically prove that the new sensing structure satisfy the Mutual Incoherence Property (3) discover a Non-tensor Wavelet Transform as the sparse basis for DHT sensing structures as well as for other DFT and DFT-like sensing matrices. (4) design a DHT computational core based on FPGA and related communication suite based on C#.
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Date Issued: 2017
Identifier: FSU_FALL2017_XI_fsu_0071E_14193
Format: Thesis

Title: Designing Time Efficient Real Time Hardware in the Loop Simulation Using Input Profile Temporal Compression.
Creator: Chatterjee, Sourindu, Faruque, Md Omar, Steurer, Mischa, Li, Hui, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: The modern day smart grid technology relies heavily on data acquisition and analysis. A distributed controller governs smart microgrid functions with one or more renewable sources and smart controllable loads. This sort of intelligent, scalable system is the primary drive for the Energy Internet (EI). Hence, in modern-day power systems engineering to analyze, understand and make efficient system design choices that capture robustness and scalability, Hardware in the Loop (HIL) simulations are...
Show moreThe modern day smart grid technology relies heavily on data acquisition and analysis. A distributed controller governs smart microgrid functions with one or more renewable sources and smart controllable loads. This sort of intelligent, scalable system is the primary drive for the Energy Internet (EI). Hence, in modern-day power systems engineering to analyze, understand and make efficient system design choices that capture robustness and scalability, Hardware in the Loop (HIL) simulations are required. Real-Time Simulations (RTS) is the state of the art technology thrusting the capstone of innovation for this industry. As engineers, we can model, simulate and validate smart grids operations more rapidly, robustly and reliably using RTS. With enough smaller time step for the simulation, the boundary between the real and the simulated systems slowly vanishes. It also enables the system to be simulated as Controller Hardware in the Loop (CHIL) or Power Hardware in the Loop (PHIL) setups, evolving and imitating the real physical world. The HIL (Hardware in the Loop) setup also enables a real data source or sink to be in the system to form the loop of exchange between the simulated system and real-world hardware which is most often a control hardware. The implementation of such a setup is made possible at Center for Advanced Power Systems (CAPS), named as Hardware in the Loop Test-Bed (HIL-TB). This evaluation architecture provides a systematic solution to HIL simulations. Now the sampling time for real-world sensors is generally in the order of microseconds, enabling this collected data to emulate the cyber-physical domain accurately. Thus, the challenge previously was to address the throughput of real-world input data into the simulated system efficiently and correctly. The quality of the Design of Simulation (DoS) using the real world data in the form of Real Time Input Profile (RTIP), improves, affects the quality of response of the real-time cyber-physical system simulation. Thus great care needs to be taken to prepare, prune and project the RTIPs to improve and enhance the system performance evaluation index. To solve this problem, partially successful attempts have been made in the direction of machine learning by using methods like clustering and regression to characterize large input profiles or by breaking them into subsections using fixed length sliding window techniques. These classic methods then perform data analysis on those sub-pieces to distinguish among a variety of input profiles and assign an index. These sub-profiles or sections would be then loaded into the simulation as environmental input to represent the physical system in the HIL simulations. This traditional procedure is observed to be arbitrary because clustering algorithms and metrics for methods like regression or classification are user-defined and there exists no standard practice to deal with huge input profiles. There have also been confusions regarding the size of the sliding window to create subsections, subsection joining logic, etc. Thus, to address this issue, the primary focus of this study is to present a systematic, controlled, reliable procedure to explore, screen, crop large input profiles and then to compress the same by selecting sections with most relative importance using a modified version of “knapsack” dynamic programming algorithm. This compression primarily aims to shrink down the total simulation time without much loss of information. The latter part of this study focuses towards response driven performance evaluation of the HIL simulations. This is ensured by targeted compression of original input profile based on the certain requirement of the simulation. This approach ensures that the control algorithm (CHIL simulations) or any other system operator is driven in a specific direction in the simulation response space by effectively sampling the input parameters space. The fully automated HIL-TB evaluation framework aided with Input Profile Time Compression (IPTC) module delivers a fast-convergent validation for the performance evaluation with relatively similar system response. In this study, the IPTC module has been applied to seven load profiles to compress their temporal length by a third. The case study used for the simulation with these RTIPs is the Future Renewable Electric Energy Delivery and Management (FREEDM) IEEE seven node system. The test results show great coherence between the uncompressed and compressed response and validate the performance of the IPTC module applied to real-world HIL simulations. Thus, it can conclude that the functionality of the IPTC module is validated by the quality of simulation response gained out of the compressed simulation as compared to uncompressed simulation. In future, endeavors can be made in this path by expanding the functionality of this compression module to not only identifying and managing important sections based on some initial assumption about the objective of the control application but also providing cognitive, autonomous understanding of the behavior of the controls and using that knowledge accomplishing compression of large input profiles.
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Date Issued: 2017
Identifier: FSU_FALL2017_CHATTERJEE_fsu_0071N_14274
Format: Thesis

Title: Fixed-Point Implementation of Discrete Hirschman Transform.
Creator: Thomas, Rajesh, DeBrunner, Victor E., DeBrunner, Linda S., Harvey, Bruce A., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer...
Show moreThomas, Rajesh, DeBrunner, Victor E., DeBrunner, Linda S., Harvey, Bruce A., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Digital Signal Processing (DSP) performs a very important role in various applications of electrical engineering like communications and signal enhancement. In many situations one finds that the DSP hardware available are fixed point processors. In these situations, it is necessary to perform DSP with high accuracy using the least amount of hardware resources. This thesis looks into an approach to calculate the two dimensional Discrete Hirschman Transform (DHT), the inverse DHT, the Hirschman...
Show moreDigital Signal Processing (DSP) performs a very important role in various applications of electrical engineering like communications and signal enhancement. In many situations one finds that the DSP hardware available are fixed point processors. In these situations, it is necessary to perform DSP with high accuracy using the least amount of hardware resources. This thesis looks into an approach to calculate the two dimensional Discrete Hirschman Transform (DHT), the inverse DHT, the Hirschman Cosine Transform (HCT) and the inverse HCT using fixed-point hardware. The complex coefficients required for the transform are calculated beforehand and saved as vectors. Special attention has been given to minimize errors due to scaling. The processed image and the original image does not show significant difference even for DFT or DCT length of 128. Mean square errors of -37 dB for the DHT and -40 dB for the HCT could be obtained for DFT and DCT lengths of 128.
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Date Issued: 2017
Identifier: FSU_FALL2017_Thomas_fsu_0071N_14271
Format: Thesis

Title: Small Signal Instability Assessment and Mitigation in Power Electronics Based Power Systems.
Creator: Ye, Qing, Li, Hui, Collins, E. (Emmanuel), Steurer, Mischa, Yu, Ming, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: Power electronics technology has been widely used in electric power system to achieve high energy efficiency and high renewable energy penetration. Small signal instability phenomena could easily occur in systems with abundant power electronics because of high order passive elements and controller interactions among power converters. These instability issues degrade power quality or even cause system failure. Therefore it is necessary to build accurate small signal models for stability...
Show morePower electronics technology has been widely used in electric power system to achieve high energy efficiency and high renewable energy penetration. Small signal instability phenomena could easily occur in systems with abundant power electronics because of high order passive elements and controller interactions among power converters. These instability issues degrade power quality or even cause system failure. Therefore it is necessary to build accurate small signal models for stability analysis and develop effective resonance mitigation techniques for stability improvement. The general stability analysis methods including eigenvalues-based method, component connection method, passivity-based method and impedance-based method have been evaluated and summarized. The impedance-based method is selected as the stability analysis tool for this research due to its advantages compared to other methods. Besides, three popular resonance suppression techniques, i.e. passive damper, active damper and virtual impedance control, are also studied and evaluated. The virtual impedance control is of interest because it does not reduce system efficiency or reliability compared to both the passive and active damper. A unified impedance-based stability criterion (UIBSC) has been proposed for paralleled grid-tied inverters. Compared to the traditional IBSC which evaluates all minor loop gains (MLGs) of individual inverter, the UIBSC assesses the derived global minor loop gain (GMLG) only once to determine system stability. As a result, the computation efforts can be significantly reduced when system contains a large number of inverters. In addition, a stability-oriented design guideline has been derived for the paralleled grid-tied inverters based on the GMLG. By using the guideline, the grid impedance, inverter filter parameters, time delays of digital control and control parameters can be analyzed or designed to meet the system stability requirement. The small signal stability of the FREEDM system is a critical issue due to the abundant power electronics devices and flexible control strategies. The impedance modeling methods for current controlled inverters, inverter stage of the SST, DAB converters are developed. The influences of control schemes on power converter terminal behaviors are analyzed as well. Stability criteria for several types of grid enabled by the SST are derived. The bidirectional power flow effect is also considered. These instability phenomena are demonstrated in ac, dc, and hybrid ac/dc grids of FREEDM system using HIL test bed. Finally, the conclusions are given and the scope of future work is discussed.
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Date Issued: 2017
Identifier: FSU_FALL2017_Ye_fsu_0071E_14130
Format: Thesis

Title: Application of Thermal Network Model for Designing Superconducting Cable Components.
Creator: Indrakanti, Shiva Charan, Pamidi, Sastry V., Foo, Simon Y., Moss, Pedro L., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer...
Show moreIndrakanti, Shiva Charan, Pamidi, Sastry V., Foo, Simon Y., Moss, Pedro L., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: High Temperature Superconductors (HTS) have the advantage of carrying direct current at zero resistance when operated below their critical temperature. At lower temperatures, these superconductors have the capability of carrying higher current densities. HTS power systems have applications in electrical power grids, defense, naval, aircraft, and industrial sectors. HTS devices enable higher efficiency while providing resiliency and reliability to power systems. This study developed models for...
Show moreHigh Temperature Superconductors (HTS) have the advantage of carrying direct current at zero resistance when operated below their critical temperature. At lower temperatures, these superconductors have the capability of carrying higher current densities. HTS power systems have applications in electrical power grids, defense, naval, aircraft, and industrial sectors. HTS devices enable higher efficiency while providing resiliency and reliability to power systems. This study developed models for superconducting cable system with two terminations, HTS cable, and cryo-cooler. The models combined electrical and cryogenic thermal aspects of the superconducting cable system. Several operating scenarios were simulated. Some contingencies such as cryo-cooler failure, circulation system failure were also modeled. A comparison of AC and DC cables was also analyzed in the system. The simulation models help in the analysis of the effects of system failure and to estimate the time required to turn off the system before the cable is affected. The results indicate that most of the heat load into the system is due to the terminations which are the interfaces between the superconducting cable and the room temperature components. In the contingency situations such as cryo-cooler failure, the time required to turn-off the system is several minutes. These results help us protect the cable from catastrophic damage during unexpected situations. Through these models, it is possible to calculate the maximum current that can be run through the system before the cable reaches a potential quench.
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Date Issued: 2017
Identifier: FSU_FALL2017_Indrakanti_fsu_0071N_14273
Format: Thesis

Title: Simulation of Li-Ion Coin Cells Using COMSOL Multiphysics.
Creator: Chepyala, Seshuteja, Moss, Pedro L., Weatherspoon, Mark H., Andrei, Petru, Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer...
Show moreChepyala, Seshuteja, Moss, Pedro L., Weatherspoon, Mark H., Andrei, Petru, Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Lithium batteries have played an important role since early 1980’s to provide us with energy for small portable devices. Due to the increasing demand and limited availability of fossil fuels there is a need to shift to renewable energy. In this thesis, the fabrication procedure for the lithium ion coin cell is extensively analyzed. A brief introduction into the lithium ion battery is discussed, the physics and chemistry of the materials is explained. Emphasis is made on the importance of...
Show moreLithium batteries have played an important role since early 1980’s to provide us with energy for small portable devices. Due to the increasing demand and limited availability of fossil fuels there is a need to shift to renewable energy. In this thesis, the fabrication procedure for the lithium ion coin cell is extensively analyzed. A brief introduction into the lithium ion battery is discussed, the physics and chemistry of the materials is explained. Emphasis is made on the importance of calendaring an electrode. LiFePO4 was mixed with the Super P, PVDF and NMP at appropriate stoichiometric amounts and half coin cells were produced with the reference electrode as lithium foil. The effects of calendaring in terms of discharge capacity, density profile and ac impedance was analyzed. The resulting material sample were analyzed in two parts, Sample A was left as is and Sample B was calendared. The calendared electrode exhibited a lower impedance when observed with the impedance test. The calendared electrode exhibited a higher discharge capacity of about 162 mAh/g at C/10 rate when compared to the uncalendared electrode with a discharge capacity of about 152 mAh/g at C/10. The experimental results were than compared to the simulated model constructed in Comsol Multiphysics. The coin cell model in COMSOL was started with use of the existing model for cylindrical cells. The parameters and equations required for the setup were analyzed and discussed. The comparison of the experimental vs simulated results yielded some preliminary information. However, this work is still in progress, for building further models with different materials for the coin cells.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Chepyala_fsu_0071N_14110
Format: Thesis

Title: Estimation of Power Density of Modular Multilevel Converter Employing Set Based Design.
Creator: Toshon, Tanvir Ahmed, Faruque, Md Omar (Professor of Electrical and Computer Engineering), Foo, Simon Y., Bernadin, Shonda Lachelle, Soman, Ruturaj, Florida State University,...
Show moreToshon, Tanvir Ahmed, Faruque, Md Omar (Professor of Electrical and Computer Engineering), Foo, Simon Y., Bernadin, Shonda Lachelle, Soman, Ruturaj, Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Medium Voltage DC (MVDC) system is becoming a captivating alternative for designing All Electric Ship (AES) for the US Navy. Modular Multilevel Converter (MMC) is considered as an essential component of MVDC systems for its scalability and efficacy. Designing such a power electronic converter for an electric ship is a challenging task in terms of volume constraints in an electric ship.Preliminary naval ship design used point based spiral design techniques, but the complexity and some...
Show moreMedium Voltage DC (MVDC) system is becoming a captivating alternative for designing All Electric Ship (AES) for the US Navy. Modular Multilevel Converter (MMC) is considered as an essential component of MVDC systems for its scalability and efficacy. Designing such a power electronic converter for an electric ship is a challenging task in terms of volume constraints in an electric ship.Preliminary naval ship design used point based spiral design techniques, but the complexity and some disadvantages of such design techniques don’t necessarily produce the most feasible cost effective design. To overcome the issue, the US Navy is exploring the application of Set Based Design(SBD) for designing naval architecture through Smart Ship System Design (S3D) to aid the early stage ship design.This thesis explores the areas of SBD to have a better understanding and knowledge of the design techniques. This is accomplished by design exercise employing SBD to design an essential component of the MVDC breaker-less architecture which is Modular Multilevel Converter. The effort begins with investigating the scaling factors for MMC and apply them to estimate the power density of the converter through exploration of SBD.The outcome of this work is expected to aid early stage ship design exercises using S3D which will enable a guideline for applying SBD concepts to integrate into ship system design.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_TOSHON_fsu_0071N_14095
Format: Thesis

Title: Low Voltage Ride-through for Photovoltaic Systems Using Finite Control-Set Model Predictive Control.
Creator: Franco, Fernand Diaz, Edrington, Christopher S., Ordóñez, Juan Carlos, Faruque, Md Omar (Professor of Electrical and Computer Engineering), Foo, Simon Y., Florida State...
Show moreFranco, Fernand Diaz, Edrington, Christopher S., Ordóñez, Juan Carlos, Faruque, Md Omar (Professor of Electrical and Computer Engineering), Foo, Simon Y., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Grid codes impose immunity requirements to the generation systems that are connected to the transmission lines. Immunity refers to the generator’s capability to overcome grid abnormal conditions. One of the requirements is to remain connected during a certain time when a fault, like voltage sag, is presented. During the fault scenario, a generator unit should remain connected for a pre-determined amount of time, and also provide reactive power to support the grid voltage. This is called low...
Show moreGrid codes impose immunity requirements to the generation systems that are connected to the transmission lines. Immunity refers to the generator’s capability to overcome grid abnormal conditions. One of the requirements is to remain connected during a certain time when a fault, like voltage sag, is presented. During the fault scenario, a generator unit should remain connected for a pre-determined amount of time, and also provide reactive power to support the grid voltage. This is called low-voltage ride through (LVRT). Initially, LVRT requirements were imposed for large generator units like wind farms connected to the transmission network; however, due to the increased penetration of distributed generation (DG) on the distribution system, new grid codes extend the mentioned capability to generator units connected to the distribution grid. Due to matured photovoltaic (PV) technology and the decreased price of PV panels, PV grid tied installations are proliferating in the utility grids; this is creating new challenges related to voltage control. In the past, DG such as PV were allowed to trip from the grid when a fault or unbalance occurred and reconnect within several seconds (sometimes minutes) once the fault had been cleared. Nevertheless, thanks to high PV penetration nowadays, the same method cannot be used because it will further deteriorate the power quality and potentially end in a power blackout. Different approaches have been considered to fulfill the LVRT requirement on PV systems. A large amount of literature focuses on the control of the grid side converter of the PV installation rather than the control of PV operation during the fault, and most control designs applied to the grid side follow classical control methods. Moreover, the effects of the grid fault on the generator side impose a challenge for controlling the PV systems since the quality of the synthesized converter voltages and currents depends on the dc link power/voltage control. This document proposes a Model based Predictive Control (MPC) for controlling a two stage PV system to fulfill LVRT requirements. MPC offers important advantages over traditional linear control strategies since the MPC cost function can include constraints that are difficult to achieve in classical control. Special attention is given to implementation of the proposed control algorithms. Simplified MPC algorithms that do not compromise the converter performance and immunity requirement are discussed.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_DiazFranco_fsu_0071E_14045
Format: Thesis

Title: Modeling and Application of Effective Channel Utilization in Wireless Networks.
Creator: Ng, Jonathan, Yu, Ming (Professor of scientific computing), Zhang, Zhenghao, Harvey, Bruce A., Andrei, Petru, Florida State University, College of Engineering, Department of...
Show moreNg, Jonathan, Yu, Ming (Professor of scientific computing), Zhang, Zhenghao, Harvey, Bruce A., Andrei, Petru, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: As a natural scarcity in wireless networks, radio spectrum becomes a major investment in network deployment. How to improve the channel utilization (CU) of the spectrum is a challenging topic in recent research. In a network environment, the utilization of a channel is measured by the effective CU (ECU), i.e., the effective time for transmission or when the medium being sensed busy over its total operation time. However, existing work does not provide a valid model for ECU. We investigate the...
Show moreAs a natural scarcity in wireless networks, radio spectrum becomes a major investment in network deployment. How to improve the channel utilization (CU) of the spectrum is a challenging topic in recent research. In a network environment, the utilization of a channel is measured by the effective CU (ECU), i.e., the effective time for transmission or when the medium being sensed busy over its total operation time. However, existing work does not provide a valid model for ECU. We investigate the relationship between ECU and the interference from other wireless transmission nodes in a wireless network, as well as from potential malicious attacking interfering sources. By examining the relationship between their transmission time and co-transmission time ratios between two or more interferers, we propose a new model based on the channel occupation time of all nodes in a network. The model finds its mathematical foundation on the set theory. By eliminating the overlapping transmission time intervals instead of simply adding the transmission time of all interferers together, the model can obtain the expected total interference time by properly combining the transmission time of all individual nodes along with the time when two or more nodes transmit simultaneously. Through dividing the interferers into groups according to the strength levels of their received interference power at the interested node, less significant interfering signals can be ignored to reduce the complexity when investigating real scenarios. The model provides an approach to a new detection method for jamming attacks in wireless networks based on a criterion with combined operations of ECU and CU. In the experiments, we find a strong connection between ECU and the received interference power and time. In many cases, strong and frequent interference is accompanied by a declination of ECU. The descending slope though may be steep or flat. When the decrease of ECU is not significant, CU can be observed with a sharp drop instead. Therefore, the two metrics, ECU and CU when properly combined together, demonstrate to be an effective measurement for judging strong interference. In addition, relating to other jamming detection methods in the literature, we build a mathematical connection between the new jamming detection conditions and PDR, the Packet Delivery Ratio, which has been proved effective by previous researchers. Thus, the correlation between the new criteria and PDR guarantees the validity of the former by relating itself to a tested mechanism. Both the ECU model and the jamming detection method are thoroughly verified with OPNET through simulation scenarios. The experiment scenarios are depicted with configuration data and collected statistical results. Especially, the radio jamming detection experiments simulate a dynamic radio channel allocation (RCA) module with a user-friendly graphical interface, through which the interference, the jamming state, and the channel switching process can be monitored. The model can further be applied to other applications such as global performance optimization based on the total ECU of all nodes in a wireless communications environment because ECU relates one node's transmission as the interference for others using the same channel for its global attribute, which is our work planned for the next step. We would also like to compare its effectiveness with other jamming detection methods by exploring more extensive experiment research.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Ng_fsu_0071E_14083
Format: Thesis

Title: Open-Source Low-Cost Internet of Things Platform for Buildings.
Creator: Liu, Xiaorui, Arghandeh, Reza, Foo, Simon Y., Li, Hui, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: Internet of Things (IOT) systems are becoming a popular concept of every smart system. Many people intend to develop various IOT systems which could be smart socket can be controlled remotely and tracking the electricity consumption to save energy or a security system for home which combines several sensors and cover a big area. The goal of this thesis was to introduce a method to construct an IOT system that can monitor different parameters. The design of this project also focused on...
Show moreInternet of Things (IOT) systems are becoming a popular concept of every smart system. Many people intend to develop various IOT systems which could be smart socket can be controlled remotely and tracking the electricity consumption to save energy or a security system for home which combines several sensors and cover a big area. The goal of this thesis was to introduce a method to construct an IOT system that can monitor different parameters. The design of this project also focused on wireless interaction in order to make the system more perceptual. The design of the system was modified several times which include a changing from using Ethernet to Wi-Fi. Ultimately, it provides an effective method for monitoring a building system which could be the temperature, humidity, photo intensity, or the movement of objects, etc. The final design fulfills the fundamental goals and there is a visualization web page for the IOT system which both includes a real time data monitoring and a real time charting. This thesis will give a thorough overview of how to build an own IOT system.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Liu_fsu_0071N_14126
Format: Thesis

Title: Investigation of Alternative Cryogenic Dielectric Materials and Designs for High Temperature Superconducting Devices.
Creator: Cheetham, Peter Graham, Pamidi, Sastry V., Ordóñez, Juan Carlos, Edringtion, Christopher S., Graber, Lukas, Foo, Simon Y., Florida State University, FAMU-FSU College of...
Show moreCheetham, Peter Graham, Pamidi, Sastry V., Ordóñez, Juan Carlos, Edringtion, Christopher S., Graber, Lukas, Foo, Simon Y., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: The consumption of electricity is seen by society as a certainty and not an uncertainty; however, there are several uncertainties about how the topology of the electrical grid will look in the future. For instance, it is expected that the demand for electricity is set to considerably increase, there will be a greater incorporation of renewable generation sources, and society will call for a decrease in the spatial footprint of the electrical power grid. To address these uncertainties, new...
Show moreThe consumption of electricity is seen by society as a certainty and not an uncertainty; however, there are several uncertainties about how the topology of the electrical grid will look in the future. For instance, it is expected that the demand for electricity is set to considerably increase, there will be a greater incorporation of renewable generation sources, and society will call for a decrease in the spatial footprint of the electrical power grid. To address these uncertainties, new technology has been proposed to replace the conventional copper devices currently utilized. One of the new technologies that has shown great promise over the last decade are superconducting power devices. The appeal of superconducting technology lies in its ability to operate at significantly higher current densities than equivalently sized copper or aluminum technologies. This increase in current density will potentially allow for the electrical power grid to operate at higher capacity and greater efficiency. In order to develop superconducting devices for high power applications, knowledge of the critical boundaries with regards to temperature, current and magnetic field need to be studied. High-voltage engineering principles also need to be studied in order to ensure that an optimal design is produced for the superconducting power device. These theoretical and practical challenges of designing superconducting power devices are discussed in Chapter 1. Chapter 2 focuses on the high-voltage engineering and dielectric design aspects of a specific superconducting power device: HTS power cables. In particular, this chapter discusses the different dielectric design topologies, cable layouts, and reviews successfully demonstrated HTS power cables. One of the current limitations of designing superconducting power devices is the lack of dielectric materials compatible with cryogenic temperatures, and this area has been the focus of my research. The main focus of my Ph.D. is the investigation of new cryogenic dielectric materials and designs, which can be separated into two main areas. The cryogenic studies on increasing the dielectric strength of gaseous helium (GHe) focused on the addition of a small mol% of various gases such as nitrogen (N2), hydrogen (H2) and neon (Ne) to GHe (Chapter 4). The studies to increase partial discharge inception voltage of GHe cooled high temperature superconducting (HTS) power cables focused on using a Polyethylene Terephthalate heat shrink to individually insulate HTS tapes (Chapter 6), as well as the development of a novel HTS cable design referred to as the Superconducting Gas-Insulated Transmission Line (S-GIL) (Chapter 7). While the research conducted can be split into different categories, the experimental techniques in preparing samples and performing measurements are consistent and are discussed in Chapter 3. From completing this research, several key findings were discovered that will help advance the development of GHe cooled superconducting devices. Here is a summary of these discoveries: • The addition of 4 mol% of hydrogen gas to GHe increases the dielectric strength by 80% of pure GHe for all pressures. This trend was seen with both AC and DC voltages and DC breakdown strengths were approximately 1.4 times higher than the AC, as expected. • By measuring the breakdown strength of 1, 2, and 4 mol% hydrogen gas mixed with GHe, a linear relationship exists between hydrogen mol% and breakdown strength. The saturation limit does not appear to have been reached, so there is potential for higher breakdown strengths with higher hydrogen mol%. However, there are potential safety concerns with regards to flammability that need to be considered for higher mol% hydrogen mixtures. • Tertiary mixtures containing 8 mol% nitrogen gas, and 4 mol% hydrogen gas mixed with GHe yielded approximately a 400% increase in the dielectric strength when compared to GHe. With the introduction of the nitrogen gas to the mixture the maximum operating pressure was limited to approximately 0.85 MPa before condensation occurred. • The partial discharge inception voltage (PDIV) measurements for a cable measured in the 4 mol% hydrogen mixture and then in GHe showed a 25% higher value when the cable was measured in the 4 mol% hydrogen mixture than in GHe. This improvement in PDIV is not as great as the 80% improvement seen in the breakdown measurements. • The Polyethylene Terephthalate heat shrink selected to provide individual insulation to HTS tapes did not allow for a high operational voltage when used as the insulation method for a HTS cable as breakdown occurred between 1-2 kV. • The development of the S-GIL allows for the full benefits of increasing the dielectric strength of GHe to be exploited. • The S-GIL will allow for higher operating voltages and better thermal characteristics than currently available for GHe superconducting power cables.
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Date Issued: 2017
Identifier: FSU_SUMMER2017_Cheetham_fsu_0071E_13956
Format: Thesis

Title: Analysis of High Switching Frequency Quasi-Z-Source Photovoltaic Inverter Using Wide Bandgap Devices.
Creator: Kayiranga, Thierry, Li, Hui, Ordóñez, Juan Carlos, Edrington, Christopher S., Pamidi, Sastry V., Lipo, Thomas A., Florida State University, FAMU-FSU College of Engineering,...
Show moreKayiranga, Thierry, Li, Hui, Ordóñez, Juan Carlos, Edrington, Christopher S., Pamidi, Sastry V., Lipo, Thomas A., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: N/A
Date Issued: 2017
Identifier: FSU_SUMMER2017_Kayiranga_fsu_0071E_13964
Format: Thesis

Title: An Isolated Modular Multilevel Multifunctional DC/DC Converter Based Battery Energy Storage System with Enhanced Fault Performance.
Creator: Mo, Ran, Li, Hui, Ordóñez, Juan Carlos, Lipo, T. A., Edrington, Christopher S., Steurer, Michael, Florida State University, College of Engineering, Department of Electrical and...
Show moreMo, Ran, Li, Hui, Ordóñez, Juan Carlos, Lipo, T. A., Edrington, Christopher S., Steurer, Michael, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: Nowadays the medium-voltage dc system (MVDC) has been proposed in the renewable energy collector fields, long distance power transmission, small-scale industrial networks and all-electric shipboards due to its relatively higher efficiency, higher flexibility and lower cost in certain applications compared to the ac grid. Batteries offer scalable energy storage solutions in these applications for high-power and long-term energy demands with high energy density. Batterers play an essential role...
Show moreNowadays the medium-voltage dc system (MVDC) has been proposed in the renewable energy collector fields, long distance power transmission, small-scale industrial networks and all-electric shipboards due to its relatively higher efficiency, higher flexibility and lower cost in certain applications compared to the ac grid. Batteries offer scalable energy storage solutions in these applications for high-power and long-term energy demands with high energy density. Batterers play an essential role to smooth the power fluctuations and stabilize the grid as well. As the interface between battery energy storage and MVDC bus, the battery energy storage system (BESS) converter is a key enabling technology with specific requirements. Due to the lack of mature dc circuit breakers, the BESS converter is desired to achieve superior dc fault response which benefits the MVDC system reliability and resiliency. In addition, considering the high expenses and limited lifetime of nowadays battery products, multiple services and functions are preferred for BESS. In this research, the isolated modular multilevel dc/dc converter (iM2DC) based BESS is proposed. It can achieve both fault current limiting and fault ride through functions with direct dc current control capability, so it is possible to maintain the system operation during fault to ensure fault localization and fast recovery. Besides, via the virtual impedance method, the proposed topology employs the converter cell capacitors rather than batteries to provide the ripple energy to achieve the active power filter (APF) function, which allows the energy storage system to improve MVDC system power quality without consuming battery lifetime or extra circuits. In addition, since the medium-frequency transformer operation frequency can be as high as the converter switching frequency, the whole system power density will be improved. A controller hardware-in-the-loop testbed, which consists of the iM2DC based BESS model simulated in the real-time digital simulator (RTDS) and the multifunctional control programmed in the ABB controller products, is utilized to validate the functionality of proposed technology. Furthermore, the system efficiency of proposed BESS is not most optimized with the sinusoidal modulation. Therefore, in this research, a novel phase-shifted square wave modulation strategy is proposed for iM2DC. Compared to the conventional modulation methods, the proposed technique achieves reduced dc inductance due to higher equivalent switching frequency. In addition, the required capacitor energy can be minimized, which decreases the capacitor size without sacrificing the total device rating. Detailed principles of the proposed modulation and passive components design are presented. A downscaled 2kW prototype is built in the lab and the experimental results are provided to demonstrate the proposed modulation strategy. Finally the dissertation work is summarized and the scope of future work is discussed.
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Date Issued: 2017
Identifier: 2018_Sp_Mo_fsu_0071E_14211
Format: Thesis

Title: Component Analysis-Based Change Detection for Sea Floor Imagery and Prelude to Sea-Surface Object Detection.
Creator: G-Michael, Tesfaye, Roberts, Rodney G., Meyer-Bäse, Anke, Meyer-Baese, U., Foo, Simon Y., Florida State University, College of Engineering, Department of Electrical and Computer...
Show moreG-Michael, Tesfaye, Roberts, Rodney G., Meyer-Bäse, Anke, Meyer-Baese, U., Foo, Simon Y., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: In undersea remote sensing change detection is the process of detecting changes from pairs of multi-temporal sonar images of the seafloor that are surveyed approximately from the same location. The problem of change detection, subsequent anomaly feature extraction, and false alarms reduction is complicated due to several factors such as the presence of random speckle pattern in the images, variability in the seafloor environmental conditions, and platform instabilities. These complications...
Show moreIn undersea remote sensing change detection is the process of detecting changes from pairs of multi-temporal sonar images of the seafloor that are surveyed approximately from the same location. The problem of change detection, subsequent anomaly feature extraction, and false alarms reduction is complicated due to several factors such as the presence of random speckle pattern in the images, variability in the seafloor environmental conditions, and platform instabilities. These complications make the detection and classification of targets difficult. This thesis presents the first successful development of an end-to-end automated seabed change detection using multi-temporal synthetic aperture sonar (SAS) imagery that include a false detection/false alarms reduction based on principal and independent component analysis (PCA/ICA). ICA is a well-established statistical signal processing technique that aims to decompose a set of multivariate signals, i.e., SAS images, into a basis of statistically independent data-vectors with minimal loss of information content. The goal of ICA is to linearly transform the data such that the transformed variables are as statistically independent from each other as possible. The changes in the scene are detected in reduced second or higher order dependencies by ICA. Thus removing dependencies will leave the change features that will be further analyzed for detection and classification. Test results of the proposed method on a data set of SAS images (snippets) of declared changes from an automated change detection (ACD) process will be presented. These results illustrate the effectiveness of component analysis for reduction of false alarms in ACD process. In the context of sea surface object detection, this thesis investigates bistatic radar engagement using synthetic aperture radar (SAR) and examines five models of the bistatic electromagnetic scattering that will support future research on SAR sea-surface change detection.
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Date Issued: 2017
Identifier: 2018_Sp_GMichael_fsu_0071E_14301
Format: Thesis

Title: Simulation Tools and Techniques for Analyzing the Impacts of Photovoltaic System Integration.
Creator: Hariri, Ali, Ordóñez, Juan, Foo, Simon Y., Edrington, Christopher S., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: Solar photovoltaic (PV) energy integration in distribution networks is one of the fastest growing sectors of distributed energy integration. The growth in solar PV integration is incentivized by various clean power policies, global interest in solar energy, and reduction in manufacturing and installation costs of solar energy systems. The increase in solar PV integration has raised a number of concerns regarding the potential impacts that might arise as a result of high PV penetration. Some...
Show moreSolar photovoltaic (PV) energy integration in distribution networks is one of the fastest growing sectors of distributed energy integration. The growth in solar PV integration is incentivized by various clean power policies, global interest in solar energy, and reduction in manufacturing and installation costs of solar energy systems. The increase in solar PV integration has raised a number of concerns regarding the potential impacts that might arise as a result of high PV penetration. Some impacts have already been recorded in networks with high PV penetration such as in China, Germany, and USA (Hawaii and California). Therefore, network planning is becoming more intricate as new technologies are integrated into the existing electric grid. The integrated new technologies pose certain compatibility concerns regarding the existing electric grid infrastructure. Therefore, PV integration impact studies are becoming more essential in order to have a better understanding of how to advance the solar PV integration efforts without introducing adverse impacts into the network. PV impact studies are important for understanding the nature of the new introduced phenomena. Understanding the nature of the potential impacts is a key factor for mitigating and accommodating for said impacts. Traditionally, electric power utilities relied on phasor-based power flow simulations for planning their electric networks. However, the conventional, commercially available, phasor-based simulation tools do not provide proper visibility across a wide spectrum of electric phenomena. Moreover, different types of simulation approaches are suitable for specific types of studies. For instance, power flow software cannot be used for studying time varying phenomena. At the same time, it is not practical to use electromagnetic transient (EMT) tools to perform power flow solutions. Therefore, some electric phenomena caused by the variability of PV generation are not visible using the conventional utility simulation software. On the other hand, EMT simulation tools provide high accuracy and visibility over a wide bandwidth of frequencies at the expense of larger processing and memory requirements, limited network size, and long simulation time. Therefore, there is a gap in simulation tools and techniques that can efficiently and effectively identify potential PV impact. New planning simulation tools are needed in order to accommodate for the simulation requirements of new integrated technologies in the electric grid. The dissertation at hand starts by identifying some of the potential impacts that are caused by high PV penetration. A phasor-based quasi-static time series (QSTS) analysis tool is developed in order to study the slow dynamics that are caused by the variations in the PV generation that lead to voltage fluctuations. Moreover, some EMT simulations are performed in order to study the impacts of PV systems on the electric network harmonic levels. These studies provide insights into the type and duration of certain impacts, as well as the conditions that may lead to adverse phenomena. In addition these studies present an idea about the type of simulation tools that are sufficient for each type of study. After identifying some of the potential impacts, certain planning tools and techniques are proposed. The potential PV impacts may cause certain utilities to refrain from integrating PV systems into their networks. However, each electric network has a certain limit beyond which the impacts become substantial and may adversely interfere with the system operation and the equipment along the feeder; this limit is referred to as the hosting limit (or hosting capacity). Therefore, it is important for utilities to identify the PV hosting limit on a specific electric network in order to safely and confidently integrate the maximum possible PV systems. In the following dissertation, two approaches have been proposed for identifying the hosing limit: 1. Analytical approach: this is a theoretical mathematical approach that demonstrated the understanding of the fundamentals of electric power system operation. It provides an easy way to estimate the maximum amount of PV power that can be injected at each node in the network. This approach has been tested and validated. 2. Stochastic simulation software approach: this approach provides a comprehensive simulation software that can be used in order to identify the PV hosting limit. The software performs a large number of stochastic simulation while varying the PV system size and location. The collected data is then analyzed for violations in the voltage levels, voltage fluctuations and reverse power flow. It is important to note that there are multiple factors that affect the hosting limits in a distribution network. Moreover, the limit can be assessed based on different parameters; however, it will be shown in this dissertation that in most cases the voltage level is the first parameter to be violated under high PV penetration conditions. Therefore, in both approaches, the voltage is considered the main factor to be monitored for violations for PV hosting limit identification. The work presented hereinafter focuses on providing novel, innovative and practical solutions for fulfilling certain gaps in power system simulation. A novel hybrid simulation tool is presented in this dissertation as a solution for some of the issues facing the simulation of distribution networks with high PV penetration. Hybrid simulation is a relatively new concept in power system simulation and has not yet been applied for studying PV impacts in distribution networks. The presented hybrid tool offers accurate results and fast simulations. It can be used for various applications regarding the study of PV impacts as will be shown in this dissertation. It interfaces an EMT model of a grid-tied PV system with a phasor-domain model of a distribution network. The presented hybrid simulation tool incorporates a phasor-domain QSTS simulation with a time-domain EMT simulation which allows for a wide range of frequency visibility. The tool offers full EMT-level visibility at the point of common coupling (PCC), as well as slow dynamic visibility through the QSTS simulation. The tool is validated and tested by comparing the results with a full EMT simulation. It is used for studying the impacts of PV systems on the distribution network during fault conditions, islanding situation, solar irrandiance variation, among many other applications. The developed tool is made completely open-source in order to promote the hybrid simulation concept in power systems simulations as a viable solution for many of the conventional simulation tool limitations. Moreover, the work presented hereinafter proposes a novel co-simulation architecture with power hardware-in-the-loop (PHIL) simulation. The proposed architecture is the first of its kind developed at the National Renewable Energy Laboratory (NREL). The co-simulation testbed is developed in order to allow for wider range of hardware testing before deploying new technologies into the field. The testbed is composed of: 1. A full phasor model of the distribution network developed using a commercial distribution management software (DMS) environment. 2. A reduced form of the full network model developed in a real-time EMT environment using Opal-RT real-time simulator. 3. A hardware setup tested in a PHIL simulation environment. The hardware setup represents a grid-tied PV system at the PCC composed of a grid simulator, PV simulator, and a PV inverter. The co-simulation allows a slow QSTS simulation to be performed using the DMS model where slow variations are simulated, such as voltage regulator operations and slow variations in loads and solar irradiance. The QSTS simulation updates the EMT model components (loads, generators, voltage sources, and voltage regulators). The reduced EMT model is solved in real-time which allows for detailed and accurate visibility of the transient phenomena occurring in the network. Finally, the EMT model communicates with the physical hardware device at the PCC in order to close the PHIL loop. This architecture expands the capabilities of conventional PHIL testing and allows for more tests and scenarios to be implemented. The co-simulation testbed is tested by solving a real feeder network model in the DMS using historic load and solar irradiance data. The phasor model updates the EMT model's loads, voltage sources, and voltage regulator status at every QSTS time-step. The EMT model communicates through the hardware interface of the real-time simulator with the hardware setup by sending command control signals to the grid simulator and the PV simulator in order to replicate the simulated conditions in the real physical hardware. The inverter is tested under different operation modes, and its capabilities to use advanced algorithms for voltage regulation are put to test. The co-simulation architecture also addresses the stability and accuracy concerns of the PHIL experiments. A detailed stability and accuracy analysis is discussed in Chapter 6.
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Date Issued: 2017
Identifier: FSU_2017SP_Hariri_fsu_0071E_13764
Format: Thesis

Title: Fuzzy Logic Based Energy Storage Management System for MVDC Power System of All Electric Ship.
Creator: Khan, Mohammed Masum Siraj, Faruque, Md Omar, Foo, Simon Y., Moss, Pedro L., Florida State University, College of Engineering, Department of Electrical and Computer Engineering
Abstract/Description: The power management strategy in a MVDC based power system of an all electric ship (AES) with Hybrid Energy Storage System (HESS) can greatly affect the energy efficiency of the system. In order to maintain the bus voltage of a medium voltage DC (MVDC) shipboard power system within the allowable margin with the operation of different types of loads, the energy storage has become indispensable part of the AES. With the aim of supporting the MVDC shipboard power system, an energy storage...
Show moreThe power management strategy in a MVDC based power system of an all electric ship (AES) with Hybrid Energy Storage System (HESS) can greatly affect the energy efficiency of the system. In order to maintain the bus voltage of a medium voltage DC (MVDC) shipboard power system within the allowable margin with the operation of different types of loads, the energy storage has become indispensable part of the AES. With the aim of supporting the MVDC shipboard power system, an energy storage management (ESM) system based on Fuzzy Logic (FL) has been proposed and its performance with a Proportional-Integral (PI) control algorithms is compared. In order to support the peak demand and pulsed load, a HESS incorporating high energy density storage (battery), and high power density storage (supercapacitor) are proposed. Based on the analysis of power flow, the load characteristics, the power management objectives, constraints and the ease of implementation in MVDC power system, the battery and super capacitor are considered as the potential storage devices. For energy transfer among the energy storages and the MVDC system, bi-directional DC-DC converters with dual active bridge (DAB) configuration are used. With the changes of the bus voltage and load power demand, the ESM systems provide instantaneous reference powers for charging or discharging of the battery and supercapacitor. The reference powers for the battery and supercapacitor are sent to the respective controllers of the DAB converters. Two power sharing strategies are designed to share power among multiple energy storages. The MVDC shipboard power system with the generators, loads, battery and supercapacitor with DAB converters are modeled in SimPowerSystems. Simulation results are used to make a comparison of performances of the FL and PI controller based ESM systems. Finally, controller hardware-in-the-loop (CHIL) based experimental results are added to demonstrate the effectiveness of the controller.
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Date Issued: 2017
Identifier: FSU_2017SP_Khan_fsu_0071N_13877
Format: Thesis

Title: Design and Analysis of a Novel High Temperature Superconducting Synchronous Machine.
Creator: Mishra, Subhendu, Pamidi, Sastry V., Lipo, Thomas A., Foo, Simon Y., Andrei, Petru, Florida State University, College of Engineering, Department of Electrical and Computer...
Show moreMishra, Subhendu, Pamidi, Sastry V., Lipo, Thomas A., Foo, Simon Y., Andrei, Petru, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: It has been clear in the recent decades that there is an urgent need to progress towards renewable energy. There are few established technologies that provide a suitable economic option. These include hydropower, solar, wind, geothermal, nuclear etc. Due to this increase of renewable energy, a lot of research is going on to develop a distributed energy system and to integrate these energy resources to the grid. There has been also a lot of research in the field of more efficient use of power...
Show moreIt has been clear in the recent decades that there is an urgent need to progress towards renewable energy. There are few established technologies that provide a suitable economic option. These include hydropower, solar, wind, geothermal, nuclear etc. Due to this increase of renewable energy, a lot of research is going on to develop a distributed energy system and to integrate these energy resources to the grid. There has been also a lot of research in the field of more efficient use of power transfer. High temperature superconductors are being seen as the new technology that can do this. Research in the field of high temperature super conductors has also led researchers to work on superconducting generators, which generate energy more efficiently. This thesis is focused on the development of a superconducting synchronous generator, for wind turbine applications. A literature review is done where all existing superconducting generators are studied. It is found from the literature review that these generators have a serious flaw. It is that the cryocoolers are mounted on the rotor of these generators and thus, it is very difficult to manage and maintain these systems. It is thus proposed that if we could completely remove the field windings from the rotor of a generator, we could significantly reduce the maintenance cost of the superconducting generator. This is based on the realization that the present topology of using superconducting windings on the rotor, which is not very reliable nor a sustainable model. Thus a new topology for a synchronous generator utilizing a superconducting field winding is proposed. A mathematical derivation of the torque output of the HTS machine is presented and compared to a conventional synchronous machine. The derivation shows that this HTS machine could produce output torque about three times that of the synchronous machine in ideal conditions. A design topology was implemented for a 12 MW offshore wind turbine generator. The machine parameters for a single stage HTS WTG were calculated and a 2D Finite Element analysis is carried out for no load and rated load conditions. A similar PM machine was then designed and compared to the HTS machine. It is found using 2D finite element method that the HTS machine gives more torque by about 80% and thus gives promising result.
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Date Issued: 2017
Identifier: FSU_2017SP_Mishra_fsu_0071N_13900
Format: Thesis

Title: Numerical Algorithms for the Atomistic Dopant Profiling of Semiconductor Materials.
Creator: Aghaei Anvigh, Samira, Andrei, Petru, Zhang, Mei, Foo, Simon Y., Zheng, Jianping P., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and...
Show moreAghaei Anvigh, Samira, Andrei, Petru, Zhang, Mei, Foo, Simon Y., Zheng, Jianping P., Florida State University, FAMU-FSU College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: In this dissertation, we investigate the possibility to use scanning microscopy such as scanning capacitance microscopy (SCM) and scanning spreading resistance microscopy (SSRM) for the "atomistic" dopant profiling of semiconductor materials. For this purpose, we first analyze the discrete effects of random dopant fluctuations (RDF) on SCM and SSRM measurements with nanoscale probes and show that RDF significantly affects the differential capacitance and spreading resistance of the SCM and...
Show moreIn this dissertation, we investigate the possibility to use scanning microscopy such as scanning capacitance microscopy (SCM) and scanning spreading resistance microscopy (SSRM) for the "atomistic" dopant profiling of semiconductor materials. For this purpose, we first analyze the discrete effects of random dopant fluctuations (RDF) on SCM and SSRM measurements with nanoscale probes and show that RDF significantly affects the differential capacitance and spreading resistance of the SCM and SSRM measurements if the dimension of the probe is below 50 nm. Then, we develop a mathematical algorithm to compute the spatial coordinates of the ionized impurities in the depletion region using a set of scanning microscopy measurements. The proposed numerical algorithm is then applied to extract the (x, y, z) coordinates of ionized impurities in the depletion region in the case of a few semiconductor materials with different doping configuration. The numerical algorithm developed to solve the above inverse problem is based on the evaluation of doping sensitivity functions of the differential capacitance, which show how sensitive the differential capacitance is to doping variations at different locations. To develop the numerical algorithm we first express the doping sensitivity functions in terms of the Gâteaux derivative of the differential capacitance, use Riesz representation theorem, and then apply a gradient optimization approach to compute the locations of the dopants. The algorithm is verified numerically using 2-D simulations, in which the C-V curves are measured at 3 different locations on the surface of the semiconductor. Although the cases studied in this dissertation are much idealized and, in reality, the C-V measurements are subject to noise and other experimental errors, it is shown that if the differential capacitance is measured precisely, SCM measurements can be potentially used for the "atomistic" profiling of ionized impurities in doped semiconductors.
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Date Issued: 2016
Identifier: FSU_2016SP_AghaeiAnvigh_fsu_0071E_13103
Format: Thesis

Title: Characterization of the Common Mode Features of a 3-Phase Full-Bridge Inverter Using Frequency Domain Approaches.
Creator: Mohebali, Behshad, Edrington, Christopher S., Steurer, Michael Morten, Li, Hui, Graber, Lukas, Florida State University, College of Engineering, Department of Electrical and...
Show moreMohebali, Behshad, Edrington, Christopher S., Steurer, Michael Morten, Li, Hui, Graber, Lukas, Florida State University, College of Engineering, Department of Electrical and Computer Engineering
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Abstract/Description: In this thesis a practical approach for characterizing the common mode behavior of the power electronic devices (PED) on board a next generation All-Electric ship (AES) power system is proposed. As the topic of AES design is becoming more and more relevant for the US navy, addressing the AES design challenges get more importance and attention. The AES power system is designed ungrounded to make the system capable of operating after a single phase to ground fault (which is the most common type...
Show moreIn this thesis a practical approach for characterizing the common mode behavior of the power electronic devices (PED) on board a next generation All-Electric ship (AES) power system is proposed. As the topic of AES design is becoming more and more relevant for the US navy, addressing the AES design challenges get more importance and attention. The AES power system is designed ungrounded to make the system capable of operating after a single phase to ground fault (which is the most common type of fault in power systems). However, the inevitable parasitic coupling in the system can cause overvoltages and spike currents in the case of ground faults. The mentioned parasitic coupling can also form a common mode loop consisting of the system conductors, the parasitic coupling effect at different locations of the system, and the ground path (which is the Ship hull in this case). High frequency contents produced by the fast switching of the power converters can circulate in the so called common mode loop. To design the best grounding scheme for AES power system accurate and reliable models of the common mode characteristics of the shipboard power systems components is needed. Among the components seen in a shipboard power system the PEDs are the most difficult parts of the system to characterize due to their non-linear time-variant nature. At the Center for Advanced Power Systems (CAPS) at Florida State University the researchers developed a general guideline for characterizing the common mode behavior of the passive components of the power system using scattering parameters measurement. In practical cases the access to the internal parts of a PED may not be available or may have significant safety issues. On the other hand, the detailed information on the operation of the PED, which is needed to characterize the common mode sources in the system, may not be given by the manufacturer. In this thesis, the impedance of the low pass filter is measured using the mentioned Scattering parameter guideline with additional considerations. A frequency domain approach is utilized to reconstruct the common mode voltage of the PED (specifically a full-bridge 3-phase inverter) at the switches by measuring the common mode current in a previously characterized test setup; which included a DC source, a common mode low pass filter, a 3-phase transmission line, and a rotational load with grounded casing. The results show that the common mode voltage of the inverter can be estimated without accessing inside the device while in operation.
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Date Issued: 2016
Identifier: FSU_2016SP_Mohebali_fsu_0071N_13066
Format: Thesis

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