Analysis, Design, and Demonstration of a 25-kW Dynamic Wireless Charging System for Roadway Electric Vehicles

Abstract

Dynamic wireless charging of electric vehicles (EVs) can significantly extend the EVs' driving range and consequently, the prospect of electrified transportation. In this paper, a comprehensive study is conducted to elaborate the constraints of real driving conditions and propose a solution that could cope with misalignment problem and the dynamics imposed by the charging process and by EVs passing over road-embedded charging pads. A dual-loop primary controller is proposed to regulate primary-side power and current. The controller allows sequential and timely activation of segmented primary coils; it controls the primary coil current at the reference value under no-load and loaded conditions, compensates for power transfer reduction caused by the vehicle lateral misalignment (LTM), and prevents primary overloading. The primary of the dynamic wireless charger is modeled using the generalized state-space averaging method and the model is verified through simulations and experiments. After that, a controller has been designed and implemented and its operation is evaluated through simulations and experimental tests. A 25-kW charging system with two primary coils is built and tested in a real environment. The measured energy efficiency is 86% for the laterally aligned vehicle, with the possibility to be increased over 90% using enhanced schemes for coils' activation and deactivation. The system is delivering an equal amount of energy for all LTMs in the range of ±15 cm, which improves the expected value of transferred energy by more than 30%.