Transmission Range Extension of PT-Symmetry-Based Wireless Power Transfer System

The wireless power transfer (WPT) system based on the parity-time (PT) symmetry has been proved to be a promising WPT system due to its characteristics of constant efficiency and output power. However, the PT-symmetric range is limited, and it is necessary to widen the PT-symmetric region to extend the distance of constant and efficient transmission. The novel PT-symmetry-based WPT system with an inductor added on the receiving circuit is proposed in this article. First, the model of the proposed system is established by utilizing the coupled-mode theory, and the performance differences between the proposed system and the original PT-symmetric system are studied, and it is found that the critical coupling coefficient of the proposed system is smaller than that of the original PT-symmetric system. Second, to improve the efficiency of the proposed structure, the method of increasing the inductance of the transmitting coil is also put forward. Finally, the experimental results are basically consistent with the theoretical results, and the validity of the proposed approach is verified.