A Frequency Multiplier Architecture for High-Power High-Frequency Capacitive Wireless Charging Systems

This paper proposes a frequency multiplier architecture for high-frequency capacitive wireless power transfer (WPT) systems using air-core transformers. The proposed architecture can reduce the inverter transistor’s switching frequency by any desired factor compared to the system’s resonant frequency, thereby improving transistor switching performance and reducing high-frequency-dependent losses. The operation of the frequency multiplier architecture is described and validated using analytical and numerical analysis. A large air-gap 6.78-MHz capacitive WPT system is designed using the proposed architecture and the tradeoffs and optimizations between the system parameters are studied. Finally, the findings of this study are verified by a prototype 6.78-MHz 12-cm air-gap capacitive WPT system.