Engineering Commons^™

Impact Of Renewables On Grid Strength, Transient Stability, And Grid Operation Characterization, Abigail E. Till

Doctoral Dissertations

Increasing amounts of inverter based resources (IBR) are being added to the grid. With environmental and climate change concerns, even more is projected to be added. Many companies and regions are setting goals for high levels of renewables.

As IBR are added to the grid, it changes how the power system responds to disturbances. With less traditional synchronous machines on the system, this decreases the inertia and can add stability concerns. Studies are required to know how power systems will respond to the change in generation resources. This dissertation contributes to studying transient stability and grid strength on the North …

Resiliency Of Power Systems In The Cyber Layer: Application To Load Forecasting And Security Assessment, Mojtaba Dezvarei

Doctoral Dissertations

Integrating sensors, actuators, and communication infrastructure in the electrical grid creates a smart grid, known as a cyber-physical system (CPS), which combines the physical framework with a cyber layer. The cyber layer is crucial as it houses the decision-making responsible for reliable operation. However, the complexity of the physical layers, due partly to the deployment of integrated battery resources (IBRs), and the cyber layer itself, introduces challenges such as reliance on measurement quality and vulnerability to data corruption from cyber threats. These challenges result in uncertainties in the CPS framework, emphasizing the need for accurate and robust responses from the …

Impacts Of High Renewable Power Grids On System Planning And Monitoring, Zhihao Jiang

Doctoral Dissertations

To achieve the goal of a carbon pollution-free electricity sector by 2035 proposed by Biden’s Administration, the U.S. power grids are expecting a dramatic transformation in the resource mix of electricity generation. This dissertation will present related research in several different aspects that will be largely affected by the clean energy transition.

The increasing size and complexity of the bulk power systems have made it more computationally burdensome to simulate the power system in full-size. As an alternative to traditional model-based methods, Chapter 2 proposes a measurement-based model reduction approach using system identification techniques. Chapter 3 presents a parameter fine-tuning …

An Automated, Deep Learning Approach To Systematically & Sequentially Derive Three-Dimensional Knee Kinematics Directly From Two-Dimensional Fluoroscopic Video, Viet Dung Nguyen

Doctoral Dissertations

Total knee arthroplasty (TKA), also known as total knee replacement, is a surgical procedure to replace damaged parts of the knee joint with artificial components. It aims to relieve pain and improve knee function. TKA can improve knee kinematics and reduce pain, but it may also cause altered joint mechanics and complications. Proper patient selection, implant design, and surgical technique are important for successful outcomes. Kinematics analysis plays a vital role in TKA by evaluating knee joint movement and mechanics. It helps assess surgery success, guides implant and technique selection, informs implant design improvements, detects problems early, and improves patient …

Distribution Locational Marginal Price In The Distribution Level Electricity Market, Xiaofei Wang

Doctoral Dissertations

The proliferation of DERs in the distribution system is driving the transition from a passive distribution system to an active and flexible one. In this context, both industrial and academic fields have proposed to extend the transmission level market to the distribution level, and various local electricity market concepts appear. At the same time, the pricing mechanism is critical for the distribution-level electricity market. Therefore, many studies have extended the locational marginal price (LMP) to the distribution locational marginal price (DLMP) to capture the characteristics of the distribution system. This dissertation presents an in-depth study of the DLMP in the …

Heuristics For Lagrangian Relaxation Formulations For The Unit Commitment Problem, Stephen Opeyemi Fatokun

Doctoral Dissertations

The expansion of distributed energy resources (DER), demand response (DR), and virtual bidding in many power systems and energy markets are creating new challenges for unit commitment (UC) and economic dispatch (ED) techniques. Instead of a small number of traditionally large generators, the power system resource mix is moving to one with a high percentage of a large number of small units. These can increase the number of similar or identical units, leading to chattering (switching back and forth among committed units between iterations). This research investigates alternative and scalable ways of increasing the high penetration of these resources.

First, …

Development Of A Soft Robotic Approach For An Intra-Abdominal Wireless Laparoscopic Camera, Hui Liu

Doctoral Dissertations

In Single-Incision Laparoscopic Surgery (SILS), the Magnetic Anchoring and Guidance System (MAGS) arises as a promising technique to provide larger workspaces and field of vision for the laparoscopes, relief space for other instruments, and require fewer incisions. Inspired by MAGS, many concept designs related to fully insertable magnetically driven laparoscopes are developed and tested on the transabdominal operation. However, ignoring the tissue interaction and insertion procedure, most of the designs adopt rigid structures, which not only damage the patients' tissue with excess stress concentration and sliding motion but also require complicated operation for the insertion. Meanwhile, lacking state tracking of …

Reducing The Levelized Cost Of Energy Of Residential Pv Inverters Through Dynamic Hardware Allocation, Kamal Sabi

Doctoral Dissertations

Renewable energy, such as wind and solar are becoming an integral part of world energy production. Photovoltaic (PV) systems are projected to constitute a large portion of the energy generation portfolio. Achieving a low-cost residential PV system will enable the wide adoption of solar energy throughout the USA. Although innovation in several areas is required to achieve this goal of a low-cost residential PV system, inverter reliability innovation is one key area that is essential. Present string inverters' lifetime is less than 15 years. Increasing their lifetime to 50 years will reduce the cost of operation and maintenance, increase energy …

Data-Driven Situation Awareness For Power System Frequency Dynamics, Hongyu Li

Doctoral Dissertations

As the penetration of renewable energy increases, system inertia decreases, causing changes in system frequency dynamics. The power industry desires situation awareness of power system frequency dynamics to ensure secure and economic operation and control. Moreover, FNET/Grideye has abundant measured data from power systems, making it possible to conduct data-driven situation awareness studies on power system frequency dynamics. This doctoral dissertation proposes several contributions: (a) Two accurate generator trip event MW estimation methods are proposed, in which one is based on long window RoCoF and another is based on multi-Beta values; (b) Two real-time system inertia estimation approaches are developed …

Measurement-Based Monitoring And Control In Power Systems With High Renewable Penetrations, Chengwen Zhang

Doctoral Dissertations

Power systems are experiencing rapid changes in their generation mixes because of the increasing integration of inverter-based resources (IBRs) and the retirement of traditional generations. This opens opportunities for a cleaner energy outlook but also poses challenges to the safe operation of the power networks. Enhanced monitoring and control based on the increasingly available measurements are essential in assisting stable operation and effective planning for these evolving systems.

First, awareness of the evolving dynamic characteristics is quintessential for secure operation and corrective planning. A quantified monitoring study that keeps track of the inertial response and primary frequency response is conducted …

Multiple Objective Co-Optimization Of Switched Reluctance Machine Design And Control, Timothy Burress

Doctoral Dissertations

This dissertation includes a review of various motor types, a motivation for selecting the switched reluctance motor (SRM) as a focus of this work, a review of SRM design and control optimization methods in literature, a proposed co-optimization approach, and empirical evaluations to validate the models and proposed co-optimization methods.

The switched reluctance motor (SRM) was chosen as a focus of research based on its low cost, easy manufacturability, moderate performance and efficiency, and its potential for improvement through advanced design and control optimization. After a review of SRM design and control optimization methods in the literature, it was found …

Geometry-Aware Methodology For Coupling Mechanism Analysis And Radiation Mechanism Analysis, Xu Wang

Doctoral Dissertations

"Due to the wide-band spectrum of digital signals, a variety of noise generators, including microprocessors, liquid crystal displays, digital microphones, high-speed traces, and double-data-rate memory modules, are found in consumer electronics products. Noise generated by digital circuits can couple to the antennas and degrade their sensitivity. Additionally, it also couples to metallic housings or heatsinks and produces a significant amount of emission. In this research, methodologies are presented to analyze the coupling and radiation mechanism in electronic devices.

To investigate the coupling between the distributive geometries in the radio frequency interference (RFI) problem, a mesh-dependent partition-based coupling mechanism analysis method …

Fiber Optic Sensors For Liquid Identifications, Wassana Naku

Doctoral Dissertations

"The fiber optic Fabry-Perot interferometer (FPI) is a widely utilized sensing configuration, offering numerous advantages over conventional electronic sensors, including high accuracy, distributed sensing capabilities, immunity to electromagnetic interference, and compact size. In this study, we propose a remarkably simple fiber optic-tip sensor system combined with machine learning techniques for the identification of pure and volatile organic liquids (VOLs).

A liquid droplet forms an extrinsic FPI (EFPI), with its effective reflectance being a function of the droplet's length. As the droplet evaporates, its length decreases. We conducted immersion tests using optical fiber tip sensors and monitored the time-transient responses of …

Design, Modeling And Analysis Of An Ac-Ac Dual Active Bridge Converter, Kartikeya Jayadurga Prasad Veeramraju

Doctoral Dissertations

"The Solid-State Transformer (SST) is gaining attention as an alternative to conventional iron-core transformers in the power electronic community. The power industry's increasing demands for smaller size, higher efficiency, and greater energy density have made the SST an attractive option. Among various power electronic converter topologies, the Dual Active Bridge (DAB) has become popular for its bidirectional power flow capability and galvanic isolation, primarily in the DC application space. Advancements in semiconductor technologies have introduced new bidirectional switches, opening avenues for novel SST topologies. This research investigates the application of the DAB as a single-stage SST and focuses on advancements …

Introduction Of A Variable Inductance Transformer For The Design Of Resonant Power Converters, Angshuman Sharma

Doctoral Dissertations

"Magnetic integration is a hot topic in power electronics that concerns the use of a transformer's leakage and magnetizing inductances purposefully in isolated power electronic converters, thereby giving the opportunity to save the cost and footprint of any additional inductor. This is of prime interest, especially in CLLLC resonant converters which require up to three inductors. For a complete integration of these inductances, the concept of a variable inductance transformer (VIT) is introduced in this thesis. A VIT is an adaptive magnetic structure that facilitates an easy adjustment of both magnetizing and leakage inductances to meet their desired values. However, …

A Hydropower Facility As An Energy Water Signal Processor, Asha Shibu

Doctoral Dissertations

In recent times, various efforts have been made to address the challenge of adequately representing hydropower systems in modeling frameworks, accounting for the lack of data to represent the multiple constraints in hydropower operation. This research is a pilot data-driven methodology for characterizing, classifying, and comparing the water-to-energy and energy-to-water signal transformations that hydropower facilities as signal processors accomplish. In this study, a Box Jenkins transfer function/noise model is used to identify the relationship between reservoir inflows and outflows. For examining the feasibility of this methodology, 5-minute fleet data for five storage and five run-of-river facilities was provided by the …

Power System Transients: Impacts Of Non-Ideal Sensors On Measurement-Based Applications, Aaron Wilson

Doctoral Dissertations

The power system is comprised of thousands of lines, generation sources, transformers, and other equipment responsible for servicing millions of customers. Such a complex apparatus requires constant monitoring and protection schemes capable of keeping the system operational, reliable, and resilient. To achieve these goals, measurement is a critical role in the continued functionality of the power system. However, measurement devices are never completely reliable, and are susceptible to inherent irregularities; imparting potentially misleading distortions on measurements containing high-frequency components. This dissertation analyzes some of these effects, as well as the way they may impact certain applications in the grid that …

Depth Estimation Using 2d Rgb Images, Taher Naderi

Doctoral Dissertations

Single image depth estimation is an ill-posed problem. That is, it is not mathematically possible to uniquely estimate the 3rd dimension (or depth) from a single 2D image. Hence, additional constraints need to be incorporated in order to regulate the solution space. As a result, in the first part of this dissertation, the idea of constraining the model for more accurate depth estimation by taking advantage of the similarity between the RGB image and the corresponding depth map at the geometric edges of the 3D scene is explored. Although deep learning based methods are very successful in computer vision and …

Decentralized Resource Allocation Through Constrained Centroidal Voronoi Tessellations, Bhagyashri Telsang

Doctoral Dissertations

The advancements in the fields of microelectronics facilitate incorporating team elements like coordination into engineering systems through advanced computing power. Such incorporation is useful since many engineering systems can be characterized as a collection of interacting subsystems each having access to local information, making local decisions, interacting with neighbors, and seeking to optimize local objectives that may well conflict with other subsystems, while also trying to optimize certain global objective. In this dissertation, we take advantage of such technological advancements to explore the problem of resource allocation through different aspects of the decentralized architecture like information structure in a team. …

Oscillation Analysis And Its Mitigation Using Inverter-Based Resources In Large-Scale Power Grids, Khaled Alshuaibi

Doctoral Dissertations

In today's interconnected power grids, forced oscillations and poorly damped low-frequency oscillations are major concerns that can damage equipment, limit power transfer capability, and deteriorate power system stability.

The first part of the dissertation focuses on the impact of a wide-area power oscillation damping (POD) controller via voltage source converter-based high voltage direct current (VSC-HVDC) in enhancing the power system stability and improving the damping of low-frequency oscillation. The POD controller's performance was investigated under a three-phase temporary line fault. The Great Britain (G.B.) power grid model validated the POD controller performance via active power modulation of VSC-HVDC through TSAT-RTDS …

Remote Human Vital Sign Monitoring Using Multiple-Input Multiple-Output Radar At Millimeter-Wave Frequencies, Toan Khanh Vo Dai

Doctoral Dissertations

Non-contact respiration rate (RR) and heart rate (HR) monitoring using millimeter-wave (mmWave) radars has gained lots of attention for medical, civilian, and military applications. These mmWave radars are small, light, and portable which can be deployed to various places. To increase the accuracy of RR and HR detection, distributed multi-input multi-output (MIMO) radar can be used to acquire non-redundant information of vital sign signals from different perspectives because each MIMO channel has different fields of view with respect to the subject under test (SUT). This dissertation investigates the use of a Frequency Modulated Continuous Wave (FMCW) radar operating at 77-81 …

Analysis And Development Of Multiple Phase Shift Modulation In A Sic-Based Dual Active Bridge Converter, Yu Yan

Doctoral Dissertations

Renewable energy adoption is a popular topic to release the stress of climate change caused by greenhouse gas. Electricity is ideal secondary energy for clean primary energy such as nuclear, wind, photovoltaic, and so on. To extend the application of electricity and reduce fossil energy consumption by transportation sectors, electric vehicles (EVs) become promising technology that can further inspire the development of renewable energy.

Battery as the core in an EV provides the energy to the motor and all on-board electric equipment. The battery charger is mainly composed of a power factor correction (PFC) and isolated DC-DC converter. Therefore, power …

Power Quality Control And Common-Mode Noise Mitigation For Inverters In Electric Vehicles, Yang Huang

Doctoral Dissertations

Inverters are widely utilized in electric vehicle (EV) applications as a major voltage/current source for onboard battery chargers (OBC) and motor drive systems. The inverter performance is critical to the efficiency of EV system energy conversion and electronics system electro-magnetic interference (EMI) design. However, for AC systems, the bandwidth requirement is usually low compared with DC systems, and the control impact on the inverter differential-mode (DM) and common-mode (CM) performance are not well investigated. With the wide-band gap (WBG) device era, the switching capability of power electronics devices drastically improved. The DM/CM impact that was brought by the WBG device-based …

Stability Analysis And Design Of Grid-Interactive Power Electronic Converters, Le Kong

Doctoral Dissertations

The increasing penetration of power electronic converters (PECs) can provide high flexibility, full controllability, sustainability, and improved efficiency for future electric power systems. However, it also introduces new challenges since the wide-frequency-band control dynamics of PECs can interact with the power system and result in different types of instability issues. To holistically address the instability issues, several research activities are conducted in this dissertation.

The modular multilevel converter (MMC), which is one of the most common PECs in high- or medium-voltage power systems, is investigated. An improved MMC dc impedance model is developed by considering both the submodule voltage and …

Power Market Cybersecurity And Profit-Targeting Cyberattacks, Qiwei Zhang

Doctoral Dissertations

The COVID-19 pandemic has forced many companies and business to operate through remote platforms, which has made everyday life and everyone more digitally connected than ever before. The cybersecurity has become a bigger priority in all aspects of life. A few real-world cases have demonstrated the current capability of cyberattacks as in [1], [2], and [3]. These cases invalidate the traditional belief that cyberattacks are unable to penetrate real-world industrial systems. Beyond the physical damage, some attackers target financial arbitrage advantages brought by false data injection attacks (FDIAs) [4]. Malicious breaches into power market operations could induce catastrophic consequences on …

Efficient Control Approaches For Guaranteed Frequency Performance In Power Systems, Samaneh Morovati

Doctoral Dissertations

Due to high penetration of renewable energy, converter-interfaced sources are increasing in power systems and degrading the grid frequency response. Synthetic inertia emulation and guaranteed primary frequency response is a challenging task. Still, there is high potential for application of highly controllable converter-interfaced devices to help performance. Renewable energy sources and demand side smart devices also need to be equipped with innovative frequency control approaches that contribute to frequency regulation operations.

First, the wind turbine generator is chosen to represent an example of a converter- interfaced source. An augmented system frequency response model is derived, including the system frequency response …

Brain Inspired Organic Electronic Devices And Systems For Adaptive Signal Processing, Memory, And Learning., Subhadeep Koner

Doctoral Dissertations

A new class of electronic device has emerged which bear the potential for low powered brain like adaptive signal processing, memory, and learning. It is a non-linear resistor with memory coined as memristor. A memristor is a two-terminal electrical device which simultaneously changes its resistance (processing information) and store the resistance state pertaining to the applied power (memory). Therefore, it can collocate memory and processing much like our brain synapse which can save time and energy for information processing. Leveraging stored memory, it can thereby help future engineered systems to learn autonomously from past experiences. There has been a growing …

Advanced Topologies Of High Step-Up Dc-Dc Converters For Renewable Energy Applications, Ramin Rahimi

Doctoral Dissertations

"This research is focused on developing several advanced topologies of high step-up DC-DC converters to connect low-voltage renewable energy (RE) sources, such as photovoltaic (PV) panels and fuel cells (FCs), into a high-voltage DC bus in renewable energy applications. The proposed converters are based on the combinations of various voltage-boosting (VB) techniques, including interleaved and quadratic structures, switched-capacitor (SC)-based voltage multiplier (VM) cells, and magnetically coupled inductor (CI) and built-in-transformer (BIT). The proposed converters offer outstanding features, including high voltage gain with low or medium duty cycle, a small number of components, low current and voltage stresses on the components, …

A Rapid And Ultra-Sensitive Biosensing Platform Based On Tunable Dielectrophoresis For Robust Poc Applications, Yu Jiang

Doctoral Dissertations

With the ongoing pandemic, there have been increasing concerns recently regarding major public health issues such as abuse of organophosphorus compounds, pathogenic bacterial infections, and biosecurity in agricultural production. Biosensors have long been considered a kernel technology for next-generation diagnostic solutions to improve food safety and public health. Significant amounts of effort have been devoted to inventing novel sensing mechanisms, modifying their designs, improving their performance, and extending their application scopes. However, the reliability and selectivity of most biosensors still have much to be desired, which holds back the development and commercialization of biosensors, especially for on-site and point-of-care (POC) …

Carbon Footprint And Cost Minimization For Grid Systems Through Day-Ahead Order And Battery Size Optimization, Omid Pourkhalili

Doctoral Dissertations

We modeled the problem of peak hours day-ahead order for smart grid companies integrating renewable energy and power storage systems. This results in optimizing day-ahead order, battery storage size, and consequently lowering the use of fossil fuels and emissions. The utility-scale power storage can balance the difference between the day-ahead forecasts and real-time consumer demand through energy arbitrage and transmission deferral for peaking capacity. We define system parameters and their associated costs and run a suggested algorithm to minimize the grid operating cost by optimizing day-ahead order amount and battery storage capacity. The model is designed to prioritize and take …