A Dual-Frequency Dual-Channel WPT System With Wide Range ZVS and Communication-Free Capability

Achieving efficient power regulation without communication in wireless power transfer (WPT) systems remains a significant challenge, particularly under varying load and coupling conditions. This paper proposes a dual-frequency dual-channel WPT system by introducing a 3rd harmonic resonant channel alongside the fundamental power channel. The 3rd harmonic current serves multiple roles: it enables communication-free synchronization via implicit phase feedback, contributes actively to power transfer, and extends the zero-voltage switching (ZVS) range of the primary-side inverter without increasing the switching frequency. A two-stage synchronous control strategy is developed to regulate power based solely on local measurements, avoiding complex sensing, parameters estimation, or digital modulation-demodulation. To control the overall size of the coupler, a compact coil design is adopted, while maintaining a competitive power density. The proposed system is validated on a 1.7 kW experimental platform. Results confirm the system's wide ZVS range and its ability to maintain stable control without communication. The system achieves a peak efficiency of 94.39%, and remains above 93.5% when the output power exceeds 50%.