A Control Strategy for ZVS Realization in LCC-S Compensated WPT System with Semi Bridgeless Active Rectifier for Wireless EV Charging

A minimum zero voltage switching (ZVS) current control strategy is proposed for the LCC-S compensated wireless power transfer system with a semi-bridgeless active rectifier. ZVS of all switches can be guaranteed in the whole voltage range and the load variations by primary series compensation capacitance designed. Moreover, zero-phase angle operation of the primary side can be ensured as much as possible by the secondary side equivalent impedance adjustment. Thanks to its secondary side structure with both buck and boost features, the high efficiency operating range is significantly enlarged compared to that of a conventional structure. A prototype has been built and the control strategy are verified by experiments. The efficiency is consistently above 88% over the full operation range, and the measured peak efficiency is close to 96%.