A Novel Frequency Control Approach for Wide Power Regulation and Full-Range ZVS in Wireless Battery Charging Systems

Frequency control is widely adopted in wireless battery charging (WBC) systems due to its inherent hardware simplicity and straightforward implementation. Nevertheless, conventional frequency control strategies are fundamentally constrained by the frequency splitting (FS) phenomenon, which significantly limits power regulation and efficiency under varying load conditions. In this paper, a novel frequency control approach is proposed to overcome the FS challenge. The underlying FS mechanism is first analyzed, and an analytical expression for the threshold load resistance that triggers FS is derived. Building on this insight, a hybrid control scheme is developed that intelligently combines constant-frequency and variable-frequency operation, enabling seamless transitions across different operating conditions. The proposed method effectively mitigates FS-related issues without imposing restrictive constraints on load conditions or coil coupling, while simultaneously achieving wide-range power regulation and full-range zero-voltage switching (ZVS) over all operating points. Experimental results demonstrate the superior performance of the proposed approach, confirming its practicality and potential for high-efficiency, robust WBC system implementation. © 2026 IEEE.