Fixed frequency wireless power transfer using series-connected variable inductors for mitigation of frequency splitting

In wireless power transfer system, the frequency splitting phenomenon occurs due to over-coupling and low impedance loads, which lead to reduced transmission power. This letter proposes a method using series-connected variable inductors (VIs) on both primary and secondary sides to avoid frequency splitting under fixed frequency condition, while zero voltage switching and zero current switching can be realized over a wide range Lastly, a 100W experimental prototype was constructed, and results indicate that at a fixed input voltage of 50V, the system achieves an efficiency of 87.3%. In comparison to the condition of FSP, the input power shows a 336% improvement, rising from 22.9W to 99.3W.