Extending the Strong-Coupling Region and Enhancing the Power Conversion Capability of the Conventional Three-Coil Pseudo-Hermitian WPT System by Using Double Receivers

Pseudo-Hermitian wireless power transfer (WPT) system relaxes the rigid symmetry constraints of the parity-time WPT system. However, with series-compensation coils, the conventional three-coil pseudo-Hermitian WPT system has two limitations. One is that it exhibits a limited transfer efficiency under a low load coefficient. The other is if a full-bridge inverter is used to implement the negative resistance, the system’s output power reaches its minimum at the bifurcation point with a maximum transfer efficiency, significantly restricting the system performance. In this article, a novel double-receiver pseudo-Hermitian WPT system incorporating an intermediate coil is proposed. Compared with the conventional system under the same load, the proposed system has two advantages. One is if the load coefficient is low, using double decoupled RXs can extend the strong-coupling region and enhance the steady transfer efficiency. The other is that a well-designed cross-coupling can be leveraged to enhance the power conversion capability, and circumvent the binary choice between the steady transfer efficiency and the output power. Experimental results demonstrate that by using the proposed system with double decoupled RXs, the strong-coupling region can be extended and the steady transfer efficiency can be enhanced. Experimental results also demonstrate that a few times enhancement in the power conversion capability can be achieved by leveraging the cross-coupling between the double RXs.