A Multi-Mhz Large Air-Gap Capacitive Wireless Power Transfer System Utilizing An Active Variable Reactance Rectifier Suitable For Dynamic Electric Vehicle Charging

This paper introduces a multi-MHz large air-gap capacitive wireless power transfer (WPT) system that incorporates an active variable reactance (AVR) rectifier to compensate for coupling variations in dynamic electric vehicle (EV) charging applications. The AVR-based WPT system maintains full power transfer over a wide range of misalignments and vehicle road clearances. A comprehensive methodology is presented to co-design the AVR rectifier with the matching networks of the WPT system such that large coupling variations are compensated while maintaining high efficiency. A 13.56-MHz, 300-W, 12-cm nominal air-gap prototype capacitive WPT system incorporating the AVR rectifier, which can be scaled up in power for EV applications, is designed, built and tested. The AVR-based prototype system maintains full power transfer for up to 45% lateral misalignment in the coupler and up to 45% increase in vehicle road clearance. In a dynamic charging scenario, the AVR-based system transfers 80% more energy during a single pass of the vehicle over the charging pad, as compared to a system without the AVR rectifier.