Design and implementation of high efficiency Wireless Power Transfer system for on-board charger of Electric Vehicle

In this paper, a high efficiency Wireless Power Transfer (WPT) system for the on-board charger of Electric Vehicle (EV) is proposed and implemented. The analysis of the proposed system based on the Thevenin equivalent circuit model to come up with a suitable design for the battery charge application is presented. The proposed Wireless Power Transfer method has adopted four-coil system with air core and its superior performance is proved by comparing it to the conventional two-coil system. In addition, since the proposed WPT converter is able to operate at an almost constant frequency regardless of the load, CC/CV charge of the battery can be simply implemented. A 6.6kW prototype is implemented with 200 mm air gap to prove the validity of the proposed method. The prototype was built and tested to verify the performance of constant current and constant voltage (CC/CV) charge. The experimental results show that the maximum efficiency of the proposed system is 97.08 % at 3.7 kW output power in the CV mode charge.