Implementation of a CC-CV wireless charging bidirectional resonant converter for electric vehicles

In this study, a contactless bidirectional power converter with magnetic induction is proposed to transfer the power bi-directionally between a DC power grid and EV battery with a digital control mechanism. In this study, the dual active full bridge is used as the energy conversion structure. The proposed symmetrical resonant topology has the following features. It can achieve a wide input and output voltage range, reduce the complexity of bidirectional circuit design, and make the converter with soft switching characteristics for reducing circuit losses. The proposed scheme with wireless energy transmission technology to transfer energy through the air gap. Besides, digital control is used to stabilize the current and the voltage for CC and CV charging requirement. Finally, the theoretical analysis is verified to achieve a 400 V DC power grid and 280−400 V battery voltage, and the two-way maximum efficiency is 90.19%. The actual charging test of the storage and release battery is carried out to verify that the control of this study can reach the CC-CV charging method.