Bidirectional Maximum-Efficiency-Point Tracking for G2V–V2G Inductive Wireless Power Transfer Under Battery-Charging and Grid-Demand Variations

Bidirectional inductive wireless power transfer (BWPT) enables electric vehicles (EVs) to support both grid-to-vehicle (G2V) charging and vehicle-to-grid (V2G) energy delivery. However, variations in battery charging conditions and grid power demands continuously change the equivalent load and shift the maximum-efficiency point (MEP) of the wireless link. This paper proposes a bidirectional maximum-efficiency-point tracking (MEPT) framework that coordinates power regulation and efficiency optimization under these mode-dependent operating conditions. In G2V mode, constant-current–constant-voltage (CC–CV) charging is demonstrated with a current reference of 10 A and a voltage limit of 84 V, corresponding to a charging power of 840 W at the CC–CV transition. In V2G mode, reverse power transfer is regulated in response to variable grid power demands, while the corresponding MEP is continuously tracked. Wi-Fi communication provides cross-side feedback between the primary- and secondary-side controllers for coordinated charging, discharging, and MEPT operation. The MEP is therefore treated as a direction-, regulation-mode-, and power-dependent operating target rather than a fixed nominal condition. Experimental validation investigates G2V–V2G power reversal, charging-mode transitions, battery/load variations, and variable V2G power commands. Performance is evaluated in terms of power regulation, MEP tracking, wireless-feedback operation, and bidirectional power-transfer efficiency.