Engineering Commons^™

Static And Dynamic State Estimation Applications In Power Systems Protection And Control Engineering, Ibukunoluwa Olayemi Korede

Doctoral Dissertations

The developed methodologies are proposed to serve as support for control centers and fault analysis engineers. These approaches provide a dependable and effective means of pinpointing and resolving faults, which ultimately enhances power grid reliability. The algorithm uses the Least Absolute Value (LAV) method to estimate the augmented states of the PCB, enabling supervisory monitoring of the system. In addition, the application of statistical analysis based on projection statistics of the system Jacobian as a virtual sensor to detect faults on transmission lines. This approach is particularly valuable for detecting anomalies in transmission line data, such as bad data or …

Fourier Analysis And Optimization Of Inductive Wireless Power Transfer For Electric Vehicle Charging, Andrew P. Foote

Doctoral Dissertations

With the growth of electric vehicle (EV) popularity, different charging options to increase user convenience and reduce charging time such as high power wireless charging are increasingly being developed and researched. Inductive wireless power transfer (WPT) systems for EVs must meet specifications such as stray field, battery power and voltage operating range, efficiency, and ground clearance. The coil geometry and design have a large impact in meeting these constraints. Typical design approaches include iterative analysis of predetermined coil geometries to identify candidates that meet these constraints.

This work instead directly generates WPT coil shapes and magnetic fields to meet specifications …

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 …

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 …

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 …

Systematic Design Of A 100 W 6.78 Mhz Wireless Charging Station Covering Multiple Devices And A Large Charging Area, Jie Li

Doctoral Dissertations

Wireless power transfer (WPT) promises to offer safe and convenient charging in consumer electronics applications. The application ranges from sub-watt medical implant device charging to watt-level household charging, further to the kilowatt electric vehicle (EV) and railway charging. At present, two industry standards are widely used to guide the WPT product design. The Qi standard describes an application that requires the receiver to be placed close to the transmitter, called "tightly coupled" WPT. The receiver coil typically has a similar size compared to the transmitter. And the operation frequency is in the kHz range. The Airfuel standard, on the other …

A Ringamp-Assisted, Output Capacitor-Less Analog Cmos Low-Dropout Voltage Regulator, Jordan Sangid

Doctoral Dissertations

Continued advancements in state-of-the-art integrated circuits have furthered trends toward higher computational performance and increased functionality within smaller circuit area footprints, all while improving power efficiencies to meet the demands of mobile and battery-powered applications. A significant portion of these advancements have been enabled by continued scaling of CMOS technology into smaller process node sizes, facilitating faster digital systems and power optimized computation. However, this scaling has degraded classic analog amplifying circuit structures with reduced voltage headroom and lower device output resistance; and thus, lower available intrinsic gain. This work investigates these trends and their impact for fine-grain Low-Dropout (LDO) …

Data Center Power System Emulation And Gan-Based High-Efficiency Rectifier With Reactive Power Regulation, Jingjing Sun

Doctoral Dissertations

Data centers are indispensable for today's computing and networking society, which has a considerable power consumption and significant impact on power system. Meanwhile, the average energy usage efficiency of data centers is still not high, leading to significant power loss and system cost.

In this dissertation, effective methods are proposed to investigate the data center load characteristics, improve data center power usage efficiency, and reduce the system cost.

First, a dynamic power model of a typical data center ac power system is proposed, which is complete and able to predict the data center's dynamic performance. Also, a converter-based data center …

A High Frequency Wireless Power Transfer System For Electric Vehicle Charging Using Multi-Layer Non-Uniform Self-Resonant Coil, Ruiyang Qin

Doctoral Dissertations

Wireless EV (Electric Vehicle) charging is an emerging technology with rapid development in the past decade. Compared to wired EV chargers, wireless power transfer (WPT) enables safe and unobtrusive charging for EVs.

This work proposes high frequency wireless charging using a self-resonant (SR) coil at several megahertz. A multi-layer self-resonant coil structure is proposed, allowing high quality factor coils to be fabricated from layers of inexpensive copper foil and dielectric film. Additionally, the self-resonant coil utilizes its interlayer capacitance for resonance, eliminating the external compensation capacitor and shrinking the overall volume of passive component to increase the power density. Comparing …

Modeling And Control Of A 7-Level Switched Capacitor Rectifier For Wireless Power Transfer Systems, Spencer Cochran

Doctoral Dissertations

Wireless power continues to increase in popularity for consumer device charging. Rectifier characteristics like efficiency, compactness, impedance tunability, and harmonic content make the multi-level switched capacitor rectifier (MSC) an exceptional candidate for modern WPT systems. The MSC shares the voltage conversion characteristics of a post-rectification buck-boost topology, reduces waveform distortion via its multi-level modulation scheme, demonstrates tank tunability via the phase control inherent to actively switched rectifiers, and accomplishes all this without a bulky filter inductor. In this work, the MSC WPT system operation is explained, and a loss model is constructed. A prototype system is used to validate the …

Modeling, Measurement And Mitigation Of Fast Switching Issues In Voltage Source Inverters, Wen Zhang

Doctoral Dissertations

Wide-bandgap devices are enjoying wider adoption across the power electronics industry for their superior properties and the resulting opportunities for higher efficiency and power density. However, various issues arise due to the faster switching speed, including switching transient voltage overshoot, unstable oscillation, gate driving and evaluation difficulty, measurement and monitoring challenge, and potential load insulation degradation. This dissertation first sets out to model and understand the switching transient voltage overshoots. Unique oscillation patterns and features of the turn-on and turn-off overvoltage are discovered and analyzed, which provides new insights into the switching transient. During the experimental characterization, a new unstable …

Impact And Application Of Real-Time Control On Stormwater Systems, Aaron A. Akin

Doctoral Dissertations

Stormwater control measures (SCMs) such as dry extended detention basins and wet ponds are common practices implemented by engineers and designers to mitigate the impact of stormwater runoff. These practices are designed based on historical rainfall data to attenuate runoff to pre-development conditions and, once they are installed, are unable to adapt to changing rainfall patterns or watershed restoration objectives. To solve these climate resiliency issues, several studies were conducted which investigated the impact of retrofitting such systems with a controllable outlet to increase or change detention times during rainfall events along with the novel instrumentation and methodologies necessary for …

Design And Implementation Of An Isfet Sensor With Integration Of An On-Chip Processor, Shaghayegh Aslanzadeh

Doctoral Dissertations

Portable sensors are used in many applications. Among them, pH sensors are suitable for quantifying and identifying various analytes in real-time and doing so non-invasively. The analytes may have environmental impact such as in water quality monitoring. The analytes may also have biological impact such as monitoring cell culture or remote patient health assessment. CMOS based sensors are compact and enable low power consumption suitable for these portable applications.

This work reports on the development of a portable CMOS based pH sensor. The contributions of this dissertation are as follows. First, a differential pH sensor, with two different sized electrodes …

Design And Implementation Of A Multi-Modal Sensor With On-Chip Security, Ava Hedayatipour

Doctoral Dissertations

With the advancement of technology, wearable devices for fitness tracking, patient monitoring, diagnosis, and disease prevention are finding ways to be woven into modern world reality. CMOS sensors are known to be compact, with low power consumption, making them an inseparable part of wireless medical applications and Internet of Things (IoT). Digital/semi-digital output, by the translation of transmitting data into the frequency domain, takes advantages of both the analog and digital world. However, one of the most critical measures of communication, security, is ignored and not considered for fabrication of an integrated chip. With the advancement of Moore's law and …

Modeling And Optimization Algorithm For Sic-Based Three-Phase Motor Drive System, Ren Ren

Doctoral Dissertations

More electric aircraft (MEA) and electrified aircraft propulsion (EAP) becomes the important topics in the area of transportation electrifications, expecting remarkable environmental and economic benefits. However, they bring the urgent challenges for the power electronics design since the new power architecture in the electrified aircraft requires many benchmark designs and comparisons. Also, a large number of power electronics converter designs with different specifications and system-level configurations need to be conducted in MEA and EAP, which demands huge design efforts and costs. Moreover, the long debugging and testing process increases the time to market because of gaps between the paper design …

Learning Multimodal Structures In Computer Vision, Ali Taalimi

Doctoral Dissertations

A phenomenon or event can be received from various kinds of detectors or under different conditions. Each such acquisition framework is a modality of the phenomenon. Due to the relation between the modalities of multimodal phenomena, a single modality cannot fully describe the event of interest. Since several modalities report on the same event introduces new challenges comparing to the case of exploiting each modality separately.

We are interested in designing new algorithmic tools to apply sensor fusion techniques in the particular signal representation of sparse coding which is a favorite methodology in signal processing, machine learning and statistics to …

Design And Implementation Of A Low‐Power Wireless Respiration Monitoring Sensor, Ifana Mahbub

Doctoral Dissertations

Wireless devices for monitoring of respiration activities can play a major role in advancing modern home-based health care applications. Existing methods for respiration monitoring require special algorithms and high precision filters to eliminate noise and other motion artifacts. These necessitate additional power consuming circuitry for further signal conditioning. This dissertation is particularly focused on a novel approach of respiration monitoring based on a PVDF-based pyroelectric transducer. Low-power, low-noise, and fully integrated charge amplifiers are designed to serve as the front-end amplifier of the sensor to efficiently convert the charge generated by the transducer into a proportional voltage signal. To transmit …

Development Of A Low Cost Biosensing Platform For Highly Sensitive And Specific On-Site Detection Of Pathogens And Infections, Cheng Cheng

Doctoral Dissertations

A highly sensitive, specific, real time, and field-deployable surveillance tool is critical to the control of pathogens and infections, as well as ecological impact of chemicals exposure. This work investigates the development of a low cost biosensing platform that can be used for viral disease diagnosis and chemical detection. The sensing mechanism is known as AC electrokinetics (ACEK) capacitive sensing. By applying an inhomogeneous AC electric field on sensor electrodes, positive dielectrophoresis is induced to accelerate the travel of analytes. The same applied AC signal also directly measures the capture of target by the probe on sensor surface. The realized …

Monolithic Perimeter Gated Single Photon Avalanche Diode Based Optical Detector In Standard Cmos, Md. Habib Ullah Habib

Doctoral Dissertations

Since the 1930's photomultiplier tubes (PMTs) have been used in single photon detection. Single photon avalanche diodes (SPADs) are p-n junctions operated in the Geiger mode. Unlike PMTs, CMOS based SPADs are smaller in size, insensitive to magnetic fields, less expensive, less temperature dependent, and have lower bias voltages. Using appropriate readout circuitry, they measure properties of single photons, such as energy, arrival time, and spatial path making them excellent candidates for single photon detection. CMOS SPADs suffer from premature breakdown due to the non-uniform distribution of the electric field. This prevents full volumetric breakdown of the device and reduces …

Design And Analysis Of A Fully-Integrated Resonant Gate Driver, Yu Long

Doctoral Dissertations

Several decades ago the resonant gate driving technique was proposed. Given the recent rapid growth in GaN HEMT power device applications for high-frequency power applications, research has been conducted in the power electronics field using resonant gate driving for GaN power devices. Previous research for resonant gate drivers for GaN HEMT devices mostly focused on implementing the gate driving function itself, and mostly for normally-on HEMT devices.

The normally-off (enhancement mode) GaN power device was introduced to the commercial market in 2009. A new resonate gate driver is proposed in this work to implement resonant gate driving for commercial high-speed …

Bi-Level Optimization Considering Uncertainties Of Wind Power And Demand Response, Xin Fang

Doctoral Dissertations

Recently, world-wide power systems have been undergone a paradigm change with increasing penetration of renewable energy. The renewable energy is clean with low operation cost while subject to significant variability and uncertainty. Therefore, integration of renewables presents various challenges in power systems. Meanwhile, to offset the uncertainty from renewables, demand response (DR) has gained considerable research interests because of DR’s flexibility to mitigate the uncertainty from renewables. In this dissertation, various power system problems using bi-level optimization are investigated considering the uncertainties from wind power and demand response.

In power system planning, reactive power planning (RPP) under high-penetration wind power …

Adopting 3d Time-Of-Flight Sensing Technology For Design Information Verification In International Safeguards, Matthew Stephen Duchene

Doctoral Dissertations

International safeguards inspectors periodically perform examinations at sensitive nuclear facilities to verify that the facilities’ designs, layouts, and functions are identical to information declared to the International Atomic Energy Agency (IAEA). Such design information verification (DIV) relies on tools and techniques—such as 3D laser range-finding (3DLR) with light detection and ranging (LIDAR) instruments—that are resource intensive. This research explores 3D Time-of-Flight (TOF) sensors as a possible alternative technology to LIDAR systems for performing spatial change-detection to enhance the DIV process.

This research uses the Microsoft Kinect Version 2 (Kinect v2) camera system, one of several commercial depth-sensing instruments that is …

Design And Implementation Of An Integrated Biosensor Platform For Lab-On-A-Chip Diabetic Care Systems, Khandaker Abdullah Al Mamun

Doctoral Dissertations

Recent advances in semiconductor processing and microfabrication techniques allow the implementation of complex microstructures in a single platform or lab on chip. These devices require fewer samples, allow lightweight implementation, and offer high sensitivities. However, the use of these microstructures place stringent performance constraints on sensor readout architecture. In glucose sensing for diabetic patients, portable handheld devices are common, and have demonstrated significant performance improvement over the last decade. Fluctuations in glucose levels with patient physiological conditions are highly unpredictable and glucose monitors often require complex control algorithms along with dynamic physiological data. Recent research has focused on long term …

Analysis And Control Of Vsc Based Hvdc System Under Single-Line-To-Ground Fault Conditions, Xiaojie Shi

Doctoral Dissertations

To take full advantage of multilevel modular converter (MMC) and extend its application in high voltage direct current (HVDC) transmission systems, the ability to deal with severe unbalanced conditions, especially under single-line-to-ground (SLG) fault, is a key requirement.

This dissertation deals with the development of a fault handling strategy, which helps HVDC systems achieve continuous energy supply and desired operation performance under temporary SLG fault conditions while ensuring a smooth and fast black start for MMC-HVDC particularly if the system has to shut down when a permanent SLG fault occurs. Several related research topics will be discussed in this dissertation. …

Wide-Area Synchrophasor Measurement Applications And Power System Dynamic Modeling, Yin Lei

Doctoral Dissertations

The use of synchrophasor measurements system-wide has been providing significant assistance for grid dynamic monitoring, situation awareness and reliability improvement. Frequency Monitoring Network (FNET), as an academia-run synchrophasor measurement system, utilizes a large number of Internet-connected low-cost Frequency Disturbance Recorders (FDRs) installed at the distribution level to measure power system dynamics and provide both online and off-line applications, such as event detection, oscillation modes estimation, event replay, etc. This work aims to further explore applications of the FNET measurements and utilize measurement-based method in dynamic modeling.

Measurement-based dynamic reduction is an important application of synchrophasor measurement, especially considering the fact …

Versatile Three-Phase Power Electronics Converter Based Real-Time Load Emulators, Jing Wang

Doctoral Dissertations

This dissertation includes the methodology, implementation, validation, as well as real-time modeling of a load emulator for a reconfigurable grid emulation platform of hardware test-bed (HTB). This test-bed was proposed by Center of Ultra-wide-area Resilient Electric Energy Transmission Network (CURENT) at the University of Tennessee, at Knoxville in 2011, to address the transmission level system challenges posed by contemporary fast changing energy technologies.

Detailed HTB introduction, including design concept, fundamental units and hardware construction, is elaborated. In the development, current controlled three-phase power electronics converter based emulator unit is adopted to create desired power system loading conditions.

In the application, …

A Low-Power Bfsk/Ook Transmitter For Wireless Sensors, Mohammed Shahriar Jahan

Doctoral Dissertations

In recent years, significant improvements in semiconductor technology have allowed consistent development of wireless chipsets in terms of functionality and form factor. This has opened up a broad range of applications for implantable wireless sensors and telemetry devices in multiple categories, such as military, industrial, and medical uses. The nature of these applications often requires the wireless sensors to be low-weight and energy-efficient to achieve long battery life. Among the various functions of these sensors, the communication block, used to transmit the gathered data, is typically the most power-hungry block. In typical wireless sensor networks, transmission range is below 10 …