A High-Power Multiphase Wireless Dynamic Charging System With Low Output Power Pulsation for Electric Vehicles

Wireless dynamic charging (WDC) of electric vehicles (EVs) is a new initiative aimed to increase EV uptake. However, pulsating output power along the driving direction is a major problem with this technology. Moreover, in order to deliver enough driving power for EVs, WDC systems must operate at high power. This article proposes a WDC system that has the capability of providing a low pulsating and high output power to EVs. The proposed WDC utilizes multiple primary windings that guarantee a homogeneous mutual magnetic flux for the receiver along the driving direction. This results in a constant induced voltage across the receiver, and hence, constant output power to charge the EV battery. High output power is realized by using multiple transmitter windings, which have been arranged in a novel winding method. The structure layout of the proposed WDC, including ferrite cores, windings, and resonant tanks, is presented. Furthermore, a theoretical analysis is conducted to determine the conditions of each winding's current phase and amplitude for achieving constant output power. The crossing mutual inductances between the different transmitter's phases are compensated by adding small capacitors in series with each transmitter winding. An optimization analysis using Maxwell 3-D simulation for both transmitter and receiver is carried out to achieve the highest coupling factor by using minimum ferrite material. The effectiveness of the proposed system is analytically demonstrated and experimentally verified using a 3-kW laboratory prototype. Finally, the performance of the proposed method is compared with similar systems presented in the literature. The comparison shows that the proposed system has the advantages of using simple control, it also eliminates communications between the primary and secondary side and delivers a normalized power of 2.25, which is 125% higher compared to conventional single-phase systems.