Electrical and Computer Engineering Commons^™

Lifecycle Carbon Footprint And Sustainability Evaluation Of Dram-Based Processing In Memory Computing Architectures, Samrat Pravin Patel

Theses and Dissertations--Electrical and Computer Engineering

The use of computing technologies has significantly enhanced several aspects of our day-to-day lives. But it has still revealed significant environmental concerns, primarily related to greenhouse gas emissions and energy consumption. Initially, the primary environmental problems associated with computing were energy consumption during device operation. However, with the rapid advancement of technology and increasing computational demands, attention has shifted towards the embodied carbon footprint. This term refers to the total greenhouse gas emissions throughout a product’s lifecycle from the extraction of raw materials to end-of-life processing. It has become increasingly significant in the context of manufacturing integrated circuits (ICs), such …

Scalable Systems And Devices For Wireless Charging Of Electric Vehicles, Donovin D. Lewis

Theses and Dissertations--Electrical and Computer Engineering

The rising adoption of electric vehicles creates new opportunities that are not possible with conventional gas-powered vehicles such as wireless charging of electric vehicles (EV). Wide-scale implementation of wireless charging could result in benefits unique to EVs such as operation without human intervention, improved charging accessibility, and even in-route wireless charging for charge-sustaining or extended driving range operation. As the technology is in the early stages of development, there are many open-ended challenges to tackle including but not limited to coil and systems cost, weight and size, stray field emissions in high-power, high-frequency operation, and dynamic wireless charging system design …

Analysis And Design Optimization Of Electric Machines With Field Intensifying Configuration, Ali Mohammadi

Theses and Dissertations--Electrical and Computer Engineering

The design and optimization of electric machines face increasing demands for efficiency, improved torque density, manufacturability, and effective utilization of materials. Meeting these demands is particularly vital in for example, electric vehicles (EVs) and renewable energy systems, where performance, reliability, and cost are critical. In this dissertation innovative field-intensifying electric machine configurations have been explored, emphasizing advanced topologies, computational modeling, and optimization techniques to advance the state of the art in electric machine design and analysis.

Electric machines with high torque density are essential for many low-speed direct-drive systems, such as wind turbines, in-wheel traction, and industrial automation. This dissertation …

Multi-Objective Design Optimization Of Power Converters For Electric Aircraft Propulsion, Ben Luckett

Theses and Dissertations--Electrical and Computer Engineering

As global focus shifts to the electrification of the aviation sector, the need for high efficiency, lightweight, and reliable electric aircraft propulsion power converter systems has become apparent. These goals can be somewhat conflicting with each other, and a single multi-domain-optimized solution is not guaranteed. The search for a design which presents satisfactory merits becomes a drudge through various trade-off studies which can expend vast quantities of manpower and time. As a remedy to this, design automation allows the process to be computer-assisted. This dissertation presents the core fundamentals for a general multi-objective design optimization framework intended for the design …

Reevaluating The Opportunity For Wind Energy In Kentucky: Advancing Technology, Changing Economics, And Generation Complementarity, Lawrence E. Holloway, Aron Patrick, Dan M. Ionel

Electrical and Computer Engineering Faculty Publications

Recent developments in wind turbine technology, new wind resource data, and new federal tax credits for renewable energy are increasing the suitability of wind electricity generation in Kentucky. In 2022, Kentucky had 68% of its electricity from coal and in 2023 was one of eight U.S. states with no utility-scale wind generation. In the past, the state has been viewed as being generally unsuitable for wind power generation. While wind is not the most economic resource in Kentucky, all states bordering the Commonwealth have wind power. Wind power generation in Kentucky appears increasingly likely in the coming decades to play …

Smart Systems For Employing Iot Devices For Monitoring And Control Of Electric Vehicle Residential Charging, Grant M. Fischer, Steven B. Poore, Rosemary E. Alden, Donovin D. Lewis, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

As the number of electric vehicles (EVs) on the road continues to increase, the rise in power demand may pose challenges, especially for the localized grid capacity during peak load events. This paper briefly reviews methods of power monitoring and load shedding such as smart charging and load management systems. An internet-of-things (IoT) power monitoring system is proposed for high-resolution power monitoring and control of J1772 standard level 2 EV charging systems to provide detailed data to enable future studies on EV grid integration. Additionally, a hardware test bench (HTB) including a DC battery emulator, oscilloscope, and commercial EV charger …

Causes And Prevention Of Thermal Runaway In Lithium-Ion Batteries — A U.S. Utility Perspective, Shaun Lavin, Kwabena Kyeremeh, Elias Nemeh, David Beyerle, Chad Alkire, Samuel Kelty, Lakshmi Srinivasan, Stephanie Shaw, Erin Minear, Haresh Kamath, Dan Ionel, Aron Patrick

Power and Energy Institute of Kentucky Faculty Publications

Lithium-ion batteries are a critically important technology for maintaining grid reliability with the integration of variable intermittent renewable energy resources. However, lithium-ion batteries also pose significant human safety and infrastructure hazards due to the inherent risk of thermal runaway, fire, and explosion, which should be understood, mitigated, and managed. While battery manufacturers have primary responsibility for the design, manufacturing, and software which are necessary to keep battery storage systems safe, electric utilities also have an important role in understanding these risks and adopting best practices to mitigate them. This paper provides background on utility-scale battery deployment, an overview of a …

Combined Machine Learning And Differential Evolution For Optimal Design Of Electric Aircraft Propulsion Motors, David R. Stewart, Matin Vatani, Rosemary E. Alden, Donovin D. Lewis, Pedram Asef, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

Electric aircraft propulsion requires highly efficient and power-dense fault-tolerant electric motors optimized for specific flight profile operation. State-of-the-art design of electric motors involves substantial computational resources and combines electromagnetic finite element analysis (FEA) and optimization techniques. This paper proposes a new approach using a physics-based machine learning (ML) multi-input univariate meta-model trained on FEA and differential evolution (DE) optimization results to predict electromagnetic torque output. Hundreds of individual designs, generated through multiple generations of a DE algorithm, are analyzed by 3D FEA to create a database, which is then employed for the training and satisfactory validation of the ML model. …

Spatiotemporal Wind Energy Assessment For Transmission Network Integration Considering The Location Of Electrical Substations And Loads, Kwabena Kyeremeh, Rosemary E. Alden, Aron Patrick, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

Wind energy is an abundant renewable resource that can support decarbonization of energy supply. It is, therefore, essential to conduct a comprehensive assessment of wind energy potential for effective transmission network planning and integration. This work introduces a spatial-temporal assessment methodology for wind energy name plate-rated power capacity that considers the locations of electrical substations and transmission lines. This methodology applies Geographic Information System (GIS) land cover data to define siting exclusions for wind turbine installations. The correlation between generated wind power and estimates of power system load, as well as capacity factor, on a sub-regional basis for specific latest …

Combined 3d Fea And Machine Learning Design Of Inductive Polyphase Coils For Wireless Ev Charging, Lucas A. Gastineau, Donovin D. Lewis, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

Wireless power transfer (WPT) technologies are currently researched and developed for charging the batteries of electric unmanned air and ground vehicles. This paper presents systems with special polyphase inductive coils, which generate rotating fields and achieve high power density and efficiency. The complex geometry is modeled and studied with 3D electromagnetic finite element analysis (FEA). In order to reduce the substantial computational effort, machine learning techniques are proposed for surrogate modeling. A deep learning algorithm is introduced to capture the physics-based relationships between geometry and electromagnetic properties in inductive coils for wireless charging. Parametric models are systematically generated and analyzed …

Accurate Synthesis Of Dysarthric Speech For Asr Data Augmentation, Mohammad Soleymanpour, Michael T. Johnson, Rahim Soleymanpour, Jeffrey Berry

Electrical and Computer Engineering Faculty Publications

Dysarthria is a motor speech disorder often characterized by reduced speech intelligibility through slow, uncoordinated control of speech production muscles. Automatic Speech recognition (ASR) systems can help dysarthric talkers communicate more effectively. However, robust dysarthria-specific ASR requires a significant amount of training speech, which is not readily available for dysarthric talkers. This paper presents a new dysarthric speech synthesis method for the purpose of ASR training data augmentation. Differences in prosodic and acoustic characteristics of dysarthric spontaneous speech at varying severity levels are important components for dysarthric speech modeling, synthesis, and augmentation. For dysarthric speech synthesis, a modified neural multi-talker …

Analysis And Design Of Synchronous Machines With Reluctance Rotor And Pm Stator Combined Excitation, Oluwaseun A. Badewa, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

This paper studies motors that are part of a general class of synchronous machines with stator-only excitation including those that may be referred to in recent literature as of the flux switching, variable flux reluctance, or hybrid excitation type. In the studied example machine, the active stator has circumferentially magnetized spoke-type PMs and concentrated toroidal coils for improved slot fill and shortened end turns. A systematic analysis of the mmf produced by the toroidal coils in the stator and open-circuit airgap flux is developed to define feasible polarities of this synchronous motor and to establish that the dominant pole pair …

New Loads And Service Factors For Distribution Transformers Following The Transition To High-Efficiency Heat Pumps, Solar Pv, And Ev Charging, Steven B. Poore, Rosemary E. Alden, Timothy Rooney, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

Replacement of conventional high-power appliances including heating ventilation and air-conditioning (HVAC) and resistive electric water heaters (EWHs) with heat pumps is expected to be implemented long-term to increase energy efficiency. Even with efficiency upgrades, future residential power demand may rise due to increasing electric vehicle (EV) penetration. Extensive experimental data from field demonstrators and regional utilities as well as thousands of synthetically generated loads are utilized to investigate the effect of heat pumps, EV charging, and distributed solar PV on residential power demand and distribution transformers. Values are established for typical rating distribution and connection to multiple houses to study …

Solar Pv And Ev Controls For Reactive Power Support On Large Distribution Systems Modeled With Experimental And Synthetic Loads, Rosemary E. Alden, Malcolm Mcculloch, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

Changes to electric power distribution equipment may be needed to adapt to distributed energy resources (DERs) such as solar photovoltaic (PV) generation and electric vehicle (EV) batteries. Within this paper, an optimization methodology for reactive power support (RPS) controls managed by utilities for EV bi-directional charger power factor and improve substation power quality and voltage across the system is proposed. An IEEE benchmark distribution system, the 123 node test feeder, is modified to include 1,765 experimental residential profiles at typical, high resolution of 15min from smart meters, solar PV generation calculated from weather data, and EV modules based on driver …

Optimal Design And Comparison Of Synchronous Machines With Inner And Outer Reluctance Rotors And Pm Or Dc Stator Combined Excitation, Oluwaseun A. Badewa, Ali Mohammadi, Donovin D. Lewis, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

This paper presents an optimal design and comparative analysis for a toroidally wound reluctance rotor synchronous machine with either PM or DC excitation in the stator. The prototype of the PM version is experimentally evaluated, and its results are used to validate the model of the DC version as they share the same topology. The stator DC-excited synchronous (SDCES) motor is optimized at different outer diameters using large-scale multi-objective differential evolution (DE) and comparatively analyzed at power ratings typical for electric traction and propulsion applications. Its performance at reduced temperatures shows increased efficiency and goodness due to reduced losses, and …

Two-Level Design Optimization Of Ac Machines With Dc Stator Excitation And Minimal Torque Ripple Using Reluctance Rotor Profile Shaping, Ali Mohammadi, Oluwaseun A. Badewa, Yaser Chulaee, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

Torque ripple mitigation in electric machines is important for a smooth and stable operation, minimize mechanical vibrations, and enhance the overall performance. In this paper, a novel two-level optimization method is proposed for the design of synchronous flux-switching and hybrid excitation machines with an innovative multi-point spline shaping method to minimize the torque ripple. This study uses models that are validated by experimental tests from a prototype with similar topology, and exemplifies the aforementioned optimization process on a 28 pole machine. The analysis results indicate that the torque ripple can be substantially reduced with improved electromagnetic torque of the electric …

Design Of High-Power Polyphase Pcb Coil Systems For Wireless Power Transfer, Donovin D. Lewis, Lucas Gastineau, Omer Onar, Malcolm Mcculloch, John F. Eastham, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

Printed circuit board (PCB) coils have been pro- posed prior for implementation as inductive wireless charging coils to minimize size and cost. Utilization of PCBs can allow for a reduced cost, improved manufacturability, and a wide range of geometric customization options. To circumvent material limitations on insulation and thermal performance, parallel paths can be implemented to divide the current per path accordingly. Within this paper, an unconventional high power PCB coil is designed employing all possible techniques for wiring with axial and radial parallel paths with equivalent transposition to minimize circulating currents. Design studies are simulated in 3D finite element …

Analytical And Fe Modeling For The Design Of Coreless Axial Flux Machines With Halbach Array And Surface Pm Rotors, Matin Vatani, Yaser Chulaee, John F. Eastham, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

This paper introduces a rapid analytical modeling approach for coreless axial flux permanent magnet (AFPM) machines featuring surface-mounted and Halbach PM array rotors. The methodology employs a 2D model at an arbitrary diameter of the machine and converts AFPM machines into an equivalent linear machine. Initially, equations for PM flux density, accounting for harmonic content, are developed for both rotor types. Subsequently, a force equation is derived for the 2D equivalent machine based on the Lorentz force equation and the stator winding factor. In the final step, a torque equation at an arbitrary diameter—specifically, the average diameter in this paper—is …

Multi-Disk Coreless Axial Flux Permanent Magnet Synchronous Motors With Surface Pm And Halbach Array Rotors For Electric Aircraft Propulsion, Matin Vatani, John F. Eastham, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

This paper presents multiple single- and multi-disk coreless axial flux permanent magnet (AFPM) motors, focusing on specific power density and reliability for electric aircraft propulsion. Several 3D finite element analysis (FEA) parametric studies were conducted to assess the geometric impacts on a single-disk coreless AFPM motor featuring two separate stators and a double-sided Halbach array rotor configuration. These studies form the foundation for the design of both single and multi-disk machines. Single-disk coreless AFPM motors with rotor back iron embedded between the stators, offering magnetically decoupled stators, are subsequently introduced. The paper concludes by presenting four multi-disk coreless AFPM motor …

Multi-Wound Axial Flux Generators With Halbach Array Rotors, Matin Vatani, Yaser Chulaee, John F. Eastham, Xiaoze Pei, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

This paper presents three coreless axial flux permanent magnet (AFPM) generator topologies that feature magnetically and electrically decoupled outputs using a single prime mover. The proposed topologies include: (1) two separate generators mounted on the same shaft, (2) a nested configuration with a smaller generator inside a larger one, and (3) a multi-wound generator with two sets of windings and different pole numbers for each rotor side. The multi-wound generator is selected for further investigation due to its superior power-to-volume ratio and the advantage of utilizing a single structure for stator cooling. The airgap magnetic flux density equation is derived …

Coordinated Controls Of Residential Ev Chargers Considering High Power Appliances, Steven B. Poore, Rosemary E. Alden, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

In addition to electric vehicle (EV) adoption, the electricity demand of the modern grid is also under change from the replacement of resistive electric water heaters (EWHs) with high-efficiency heat pump electric water heaters (HPWH). Typical load of a HPWH has two parts: a low power compressor and a backup high power resistive boosting element. Within this paper, residential load from a large field demonstration for over one thousand homes is simulated in virtual power plant (VPP) operation with realistic HPWH and EV synthetic modules based on big data from the latest CBECC-Res and National Household Travel Survey (NHTS). Simultaneous …

Comparative Analysis Of Motors With Inner And Outer Reluctance Rotors And Pm Stators, Oluwaseun A. Badewa, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

This paper presents a comparison of special outer and inner reluctance rotor motor topologies with permanent magnet (PM) stators having toroidal AC windings. A systematic approach is taken to study and discuss the design geometries, the respective impact on performance, and adoption of technological advancements such as stator-only cooling and hair-pin winding for high slot fill factor. Parametric FEA models are developed for both topologies, and design of experiments (DoE)-based sensitivity analysis is used to study the effect of independent variables on specific performance metrics such as torque, motor loss, torque ripple, and power factor. Inner and outer rotor topologies …

Sensorless Control Of Low Inductance Coreless Afpm Machines For Fault-Tolerant Operation Of Propulsion Systems, Yaser Chulaee, Ali Mohammadi, Aaron M. Cramer, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

In motor-drive systems utilized in safety-critical applications and demanding conditions like electric aircraft propulsion systems, the reliability of the system is greatly affected by position sensors, given their susceptibility within the motor drive system. Consequently, there is a need to eliminate sensors in vector-controlled motor drives to decrease overall hardware complexity and expenses, bolster the mechanical durability and dependability of the drive system. In this paper, a fault-tolerant sensorless control system for low inductance coreless axial flux PM (AFPM) machines, integrated into electric aircraft propulsion systems, is introduced. The proposed control system spans a wide operating range, from zero to …

Fault-Tolerant Axial Flux Coreless Pm Machines With Independent Phase Modules, Yaser Chulaee, Ali Mohammadi, Dan M. Ionel, Matin Vatani

Electrical and Computer Engineering Graduate Research

In this paper, a fault-tolerant two-phase high power coreless axial flux PM (AFPM) machine with a modular structure is introduced. The performance of this machine, in terms of torque, power density, and efficiency, is compared with its three-phase counterpart configuration based on finite element analysis (FEA) and experimental results. The fault tolerance of these two configurations, considering the control systems, is also compared. A detailed power loss breakdown for the prototype two-phase and three-phase printed circuit board (PCB) stator coreless AFPM machines derived from experiments is presented, showcasing that the introduced fault-tolerant two-phase machine has comparable performance and efficiency, while …

High-Power Polyphase Pcb-Type Inductive Coupler For Wireless Electric Vehicle Charging, Donovin D. Lewis, Omer Onar, Lucas Gastineau, John F. Eastham, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

The cost and manufacturing difficulty of traditionally wound coils for wireless charging of electric vehicles has led to the exploration of alternative manufacturing for scalable deployment at a range of rated powers. A rotating-field polyphase wireless coupler is developed with balanced fully pitched coils which are not possible with conventional Litz wire. The usage of printed circuit board (PCB) technology is proposed for the innovative construction at large dimensions due to reduced cost, increased ease of manufacturability, and potential geometric customization compared to would coils. Design considerations specific to PCBs are detailed for wireless power transfer coils including advantages such …

Comparative Analysis Of Vernier Machines With Spoke, Surface Mounted, And Halbach Pm Rotors For In-Wheel Traction, Ali Mohammadi, Aaron M. Cramer, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

Axial-flux Permanent Magnet (AFPM) machines are well-suited for in-wheel traction in electric vehicles due to their compact structure and higher torque density. This paper presents a large-scale design optimization of an axial-flux permanent magnet vernier machine (PMVM) of the MAGNUS type with a double stator configuration. The active stator features double layer wound coils, while the passive stator is unwound but has a similar profile. The reference design employs a rotor with permanent magnets (PMs) arranged in a spoke-type field intensifying pattern, providing high flux concentration. Design optimization was performed using 3-D electromagnetic Finite Element Analysis (FEA) and the Differential …

On The Optimal Design Of Coreless Afpm Machines With Halbach Array Rotors For Electric Aircraft Propulsion, Matin Vatani, Yaser Chulaee, Ali Mohammadi, David R. Stewart, John F. Eastham, Dan M. Ionel

Electrical and Computer Engineering Graduate Research

This paper presents and evaluates the optimal design of a coreless axial flux permanent magnet (AFPM) motor for electric aircraft propulsion. Ferromagnetic cores are entirely removed from the machine’s structure to improve the specific power density and efficiency. An approach for envelope design optimization of the proposed motor is introduced, considering the polarity as an independent variable and employing an evolutionary algorithm and 3D Finite Element Analysis (FEA). In addition to the proposed electric motor’s electromagnetic performance, fault-tolerant capability and thermal management are considered in the optimization procedure. The optimization results and similar studies from power electronic and thermal management …

Ultra‐Fast Finite Element Analysis Of Coreless Axial Flux Permanent Magnet Synchronous Machines, Yaser Chulaee, Dan Ionel

Power and Energy Institute of Kentucky Faculty Publications

Large‐scale design optimisation techniques enable the design of high‐performance electric machines. Electromagnetic 3D finite element analysis (FEA) is typically employed in optimisation studies for accurate analysis of axial flux permanent magnet(AFPM) machines, which require extensive computational resources. To reduce the computational burden, a FEA‐based mathematical method relying on the geometric and magnetic symmetry of coreless AFPM machines is proposed to estimate the machine performance indicators using the least number of FEA solutions, thereby significantly lowering the running time. This method is generally applicable to AFPM machines with low saturation effects and cogging torque as exemplified for a printed circuit board …

Design Optimization Of A Direct-Drive Wind Generator With A Reluctance Rotor And A Flux Intensifying Stator Using Different Pm Types, Ali Mohammadi, Oluwaseun A. Badewa, Yaser Chulaee, Donovin D. Lewis, Somasundaram Essakiappan, Madhav Manjrekar, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

This paper presents a large-scale multi-objective design optimization for a direct-drive wind turbine generator concept that is based upon an experimentally validated computational model for a small-scale prototype motor of the same type. By integrating an outer reluctance-type rotor and a segmented stator with toroidally wound single-coil modules containing spoke-type PMs, the design optimization aims to minimize losses, active mass, and torque ripple while adhering to a power factor constraint. The AC windings and PMs are positioned in the stator and this concept enhances flux concentration, enabling the use of more affordable high energy non-rare-earth (special type) magnets. The exterior …

Rethinking Wind In Kentucky, Lawrence E. Holloway, Aron Patrick, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Recent analyses and developments suggest that wind energy could play a role in Kentucky's future power generation mix. This recent change in outlook for Kentucky wind has been driven by three factors: (1) improved wind turbine technologies, (2) improved economics, and (3) recent analyses showing improved grid reliability due to wind's complementarity to solar power generation.