A Single-Switch WPT Circuit With Inherent CCO–CVO for Battery Charging

In order to obtain a highly reliable and low-cost wireless charging method, this article proposes a single-switch wireless power transfer (WPT) circuit with inherent constant-current output (CCO) and constant-voltage output (CVO) for battery charging. Compared with a full-bridge WPT circuit, the structure and control strategy of the proposed circuit are simple. And the shoot-through problem could be avoided in the proposed circuit. In order to realize the inherent CCO–CVO without the wireless communication and extra control circuit, the double-D quadrature (DDQ) coils are used in this article to remove cross-coupling between coils. And the corresponding compensation network is designed to realize the automatic transition from the CCO to CVO. There are no active control schemes used in the proposed method. The compensation design could enable primary-side protection of over current against the accidental removal of the secondary side. There is no compensation inductor in the secondary circuit, which reduces the volume and weight of the secondary circuit. Moreover, the transfer gain does not rely on the transformer parameters, and more parameters design freedom can be realized. Finally, the simulation and the experimental verification are carried out to verify the superiority of the proposed circuit.