Optimized Electric Vehicle Wireless Chargers With Reduced Output Voltage Sensitivity to Misalignment

In this article, an optimized design of wireless charger for electric vehicle (EV) applications is presented to reduce the misalignment effect on the output voltage and efficiency of the wireless charger system. The existing methods to regulate the output voltage require either the communication link between the EV and charging station to control the charging station converter or a dc-dc converter on the EV. This article provides a solution to optimize compensation networks to reduce output voltage sensitivity with respect to misalignment and improve the efficiency of the overall system. Four topologies are studied in details, and the optimized compensation network is developed for each topology. The compensation networks are also designed to satisfy zero voltage switching (ZVS) for a wide range of misalignments. The performance of the optimized circuits is compared in detail in terms of efficiency, output voltage performance, size of the resonant network, and power loss distribution. This article also shows that LCC-LCC and LCC-series are the best candidates for operation in a wide range of misalignments. A 500-W/85-kHz prototype charger is built for each topology, and the performance of the optimized resonant networks is evaluated experimentally.