An LC-LCL-compensated Capacitive Power Transfer Converter Adapted for ZVS Operation of Inverters

Conventional capacitive power transfer (CPT) converters are typically designed for a zero-phase-angle (ZPA) input by enforcing a purely resistive input impedance of the compensation network. In MHz-range implementations, however, achieving inverter zero-voltage switching (ZVS) usually requires an extra series inductor or post-design parameter tuning, which increases design complexity and may detune the resonance, degrading power transfer performance. This paper proposes an LC–LCL-compensated CPT converter that co-designs the inverter and compensation network such that the input impedance is intentionally weakly inductive to provide the required dead-time current for charging/discharging GaN-FET output capacitances, enabling ZVS without any additional components or post-tuning. Moreover, the proposed network uses only five passive components to simultaneously realize zero reactive power circulation in the coupler and load-independent output, representing the minimum component count among CPT compensation networks that meet both conditions. A 275-W prototype is built to validate the concept, achieving 92% DC–DC efficiency while maintaining the desired ZVS and coupler-reactive-power-elimination characteristics.