A Bidirectional Wireless Power Transfer EV Charger Using Self-Resonant PWM

This letter suggests a large air-gap bidirectional wireless power transfer charger for electric vehicle. It is controlled by pulse width modulation with a self-resonant frequency formed by self-inductance and resonant capacitor so that constant frequency operation can be accomplished under large air-gap without additional current chopper. The feasibility of the proposed method has been verified with a 6.6-kW prototype with air-gap of 12-20 cm.