Design of CPT System With Multiple Constant Output Voltage Pickups Using Inverse Hybrid Parameters of Capacitive Coupler

This paper proposes a CPT system with multiple constant voltage (CV) pickups against variation of load resistance and the pickups moving in and out. Firstly, a new equivalent circuit of the capacitive coupler is proposed by using the inverse hybrid parameters. Based on this model, an LCLC-compensated network is analyzed and designed to achieve a constant voltage on the transmitting plates with different number of pickups. Also, a simple series-compensated circuit is adopted at the secondary side to reduce the complexity of pickups and obtain a CV output when the load resistance changes. To verify the proposed modelling and design method, a 300W experimental prototype of the LCLC-LC compensated CPT with two pickups is constructed. The experimental results show the output voltage of the system is almost unchanged and the inverter voltage and current remain in phase, when the load resistance varies and some of pickups are removed. The system efficiency remains above 85% under different conditions.