To realize a high-power density capacitive coupler for miniaturized rotary application

a parameter design method is proposed in this article. Since a capacitive coupler is composed of metal plates and external capacitors

limitations include two parts. One is air breakdown voltage limitation of metal plates

and the other one is withstanding voltage limitation of external capacitors. To quantify voltage limitation

voltage stress is analyzed. Then

an optimal design method for external capacitors is proposed

realizing minimum voltage stress and optimal load condition

simultaneously. Using an optimal external capacitor

a parameter design method is proposed to maximize power density. In which

the air breakdown voltage limitation determines the range of resonant frequency. Then

the withstanding voltage limitation determines specific resonant frequency and composition of external capacitors. Experimental results show the proposed method can realize DC-DC efficiency of 91.35% and power density of 423 W/in

3

under a 1 kW output condition.