Equivalent Circuit Approach for Output Characteristic Design of Capacitive Power Transfer

A simple equivalent circuit of the capacitive coupler and the compensator topology is presented to provide a design procedure for a capacitive power transfer (CPT) system. After that, the voltage gain curve is plotted to analyze the output characteristic of the CPT. This approach is needed in the frequency-controlled CPT stage without any post-regulator, since the output has to be operated in some charging characteristics, such as the load-independent constant current (CC) and constant voltage (CV) outputs that strongly rely on the gain curve design. Therefore, the circuit derivation and the gain curve plot is presented in this brief. Finally, the four-plate compact CPT design with LCL-compensated topology with 100 V output voltage and 450 W output power is experimentally tested to verify the design approach. The plate air-gap distance is 50 mm, and the maximum efficiency of the proposed system is 72%.