Dynamic Wireless Charging System for EVs With Uniform Voltage Output Based on Flux Pipe Supply Rail and H-Type Receiver

Abstract

For dynamic wireless power transfer (DWPT) systems employed in electric vehicles (EVs), the magnetic couplers with bipolar power supply rails, such as I-type, S-type, and n-type, provide narrow rail width while accompanying large output fluctuation. In contrast, W-type and U-type rails possess the advantage of uniform output but suffer from wide rail width and poor anti-misalignment ability. This article proposes a magnetic coupler composed of a flux pipe power supply rail and an H-type receiver to obtain the merits of the aforementioned magnetic couplers. By winding the rail coil unidirectionally along the traveling direction, a relatively uniform magnetic field in the traveling direction replacing the traditional alternating magnetic field in the vertical direction is generated. The coil of the H-type receiver is divided into two parts and wound in the same direction as the rail coil. The spatial phase difference between the two coils is 180° to offset the mutual inductance fluctuations and thereby realize uniform power output. Finally, a 2.5-kW prototype is constructed and the experimental results show that the output voltage has ±0.35% fluctuation during the traveling process and a 13.7% reduction when the misalignment varies from 0 to 25 cm.