Effects of Control Strategies on AC-DC Conversion Efficiency in EV Wireless Charging

In this paper, the performance of an AC-DC rectifier for Electric Vehicle (EV) wireless charging operated under two different control strategies are compared. The first control technique results in a Zero Current Switching (ZCS) for the power switches and is named ZCS-C (Zero Current Switch Control), the second one does not allow this operation and is named NZCS-C. The two control strategies make the rectifier input equivalent impedance to be different. In detail the ZCS-C result in an equivalent impedance constituted by both an active and a reactive part, while the NZCS-C make the rectifier impedance to be only real and, therefore, the circulating current is lower in the latter. The effect of the equivalent impedance on the transmission efficiency and the effect of the operation in Zero Current Switching (ZCS) to the AC-DC conversion efficiency are evaluated. The control strategy which allows to operate at higher efficiency is identified.