Author ORCID Identifier

https://orcid.org/0000-0001-8435-4030

Date Available

12-16-2025

Year of Publication

2025

Document Type

Doctoral Dissertation

Degree Name

Doctor of Philosophy (PhD)

College

Engineering

Department/School/Program

Electrical and Computer Engineering

Faculty

Dan M. Ionel

Faculty

Daniel Lau

Abstract

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 and integration into roadways. This dissertation explores and proposes potential solutions for several challenges including considering user participation and availability for vehicle-to-grid operation, new design and control methodologies for dynamic, on-road charging systems, electromagnetic shielding for stationary, high-power polyphase coils, and alternative manufacturing of inductive wireless charging coils with printed circuit boards.

Following the introduction, Chapter 2 proposes a software framework for clustered economic dispatch of dispatchable firm generation considering technology-specific limitations and varying capacities of intermittent weather-varying energy generation. Simulated case studies were conducted using a network of high-performance computers with second resolution simulation across an example year and resulting dispatch was compared in overall costs and flexibility. The modeling techniques developed were then adapted for an electric vehicle charging and vehicle to grid operation study to calculate the potential benefits of system contributions with varying user participation, rated charger power, and energy storage capacity ratings. Two methods were proposed for electric vehicle parameters: an aggregate considering all vehicles as a grouped energy storage and charger power and a distributed model considering electric vehicle clusters that share similar user behavior and ratings. Optimization is employed for capacity sizing of battery energy storage, wind, and solar PV systems and comparison of costs including improved availability with dynamic on-road wireless charging systems.

In Chapter 3, methodologies are developed for the analysis and mitigation of impacts on power demand as it would vary with traffic flow on a dynamic wireless charging integrated highway considering measured traffic volume and variation in traffic speed. Traffic volume compensation is proposed to maximize converter capacity factor and minimize peak power demand including a mixture of multiple pads per power electronic converters and integrated battery energy storage for redirected lane energization. The impact of cars driving slower than intended for the dynamic wireless charging roadway is mitigated through a proposed power electronic control considering the incoming car relative a pre-defined minimum speed. Experimental results from a dynamic wireless charging track were used for system analysis at low and high powers and with varying vehicle speeds. Mitigation of variation in expected in-route wireless charging demand with traffic flow can derisk potential roadway implementations at scale.

Chapter 4 involves the design and simulation of shielding coils for high-power polyphase coils developed for stationary charging applications. Standards for wireless charging define a maximum intensity for magnetic field emissions to the sides of the vehicle under test and charging. While polyphase rotating-field coils have benefits including high power density and lower passive component ratings, few studies have investigated shielding methods to reduce magnetic field emissions below the acceptable limits. Numerous strategies are reviewed for passive, active, and hybrid shielding of wireless charging coils. An electromagnetic finite element model validated against an experimental prototype is used to design and test passive and active shielding methods. Reduction of magnetic field emissions enables the high-power operation and utilization of polyphase coils with a comparison of effective shielding especially considering the impact on mutual coupling and misalignment, allowing for reduction in charging time and of wired charger demand at-scale.

The design, simulation, and experimental validation in Chapter 5 works to develop a first-of-its-kind bipolar coil with a PCB form factor. Compared to conventional Litz wire coils, which are typically used for high-frequency conductors due to a small strand size, PCBs are modular, have larger geometrical configurability, reduced volume, and the potential for very low-cost manufacturing. To mitigate reduced fill factor because of current manufacturing practices, a combination of 2D and 3D FEA modeling is developed for maximum mutual inductance, minimal resistance design of PCB wireless charging coils. New methods for equivalent transposition and phase interleaving are also developed, which allow for parallel connected layers without significant circulating currents. A series of PCB coils were designed, prototyped, and measured with a comparison of inductance and resistance including with planar parallel paths and slits, series and parallel connections between PCBs, and varying conductor thickness. The design methods proposed can be employed for systematic optimization of PCB coils in either single-phase or multi-phase operation with maximal inductance, minimal resistance for a given size and system complexity, enabling design, development, and implementation at scale.

In Chapter 6, circuit-level systems are modeled, simulated, and experimentally prototyped in a laboratory scale DC-DC test bench for the PCB coil prototypes. The impact of ultra-high mutual inductance when using many-turned wireless charging coils and series-series resonant compensation is evaluated analytically, through power electronics simulation, and experimentally with a GaN full-bridge inverter. Fundamental harmonic approximation of single-phase circuits are used to evaluate effective operating points with open-loop PWM inverter excitation. Additionally, multi-phase systems up to 6 phases are simulated using the experimentally validated model to approximate the non-linear variation in total output power with added phases for the selected geometry. Studying circuit-level behavior can approximate realistic operating points including output voltage and efficiency and lead to informed decisions in system design for scalable implementation of PCB WPT coils.

In exploring several of the open questions for wireless electric vehicle charging, this dissertation contributes to the conceptual development of future scalable wireless charging systems and devices, enabling opportunities for unique capabilities with electric vehicles such as vehicle to grid operation, in-route charging, and convenient, maximally available high-power density charging.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2025.590

Funding Information

This work was supported by the Otis A. Singletary Graduate Fellowship in 2021 and the National Science Foundation (NSF) under the NSF Graduate Research Fellowship through Grant No. #2239063 from 2022 to 2025. The support of University of Kentucky through the L. Stanley Pigman Chair in Power Endowment from 2021 to 2025 and the Lighthouse Beacon Foundation from 2024 to 2025 is also gratefully acknowledged. Any findings and conclusions expressed herein are those of the authors and do not necessarily reflect the views of the sponsors.

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