Gallium Nitride (GaN) based High-Power Multilevel H-Bridge Inverter for Wireless Power Transfer of Electric Vehicles

TL;DR

This paper introduces a high-power GaN-based multilevel H-bridge inverter designed for efficient wireless charging of electric vehicles, demonstrating simulation and experimental validation of low-distortion output at 85 kHz.

Contribution

It presents a novel 75-kW 3-level and 4-level GaN inverter design with a control strategy for EV wireless charging, validated through simulation and experiments.

Findings

Simulation confirms low harmonic distortion in output voltage.

Experimental results validate inverter performance at different power levels.

GaN inverter effectively excites wireless charging coils at 85 kHz.

Abstract

This paper presents a design and implementation of a high-power Gallium Nitride (GaN)-based multilevel Hbridge inverter to excite wireless charging coils for the wireless power transfer of electric vehicles (EVs). Compared to the traditional conductive charging, wireless charging technology offers a safer and more convenient way to charge EVs. Due to the increasing demand of fast charging, high-power inverters play a crucial role in exciting the wireless charging coils within a wireless power transfer system. This paper details the system specifications for the wireless charging of EVs, providing theoretical analysis and a control strategy for the modular design of a 75-kW 3-level and 4-level Hbridge inverter. The goal is to deliver a low-distortion excitation voltage to the wireless charging coils. LTspice simulation results, including output voltage, Fast Fourier Transform (FFT) analysis for both 3-level and 4-level H-bridge inverters, are presented to validate the control strategy and demonstrate the elimination of output harmonic components in the modular design. A GaNbased inverter prototype was employed to deliver a 85-kHz power to the wireless charging pads of the wireless power transfer system. Experimental results at two different voltage and power levels, 100V-215W and 150V-489W, validate the successful performance of the GaN inverter in the wireless charging system.