Design of a Double-Sided LC Compensated Capacitive Power Transfer System With Capacitor Voltage Stress Optimization

Abstract

Capacitive power transfer (CPT) systems usually have high voltage stresses among coupler plates and compensation capacitors due to small coupling capacitances. High voltages across the coupler plates will incur the strong electric field emission, and it is thus difficult to select compensation capacitors with high voltage stresses. To solve this problem, this brief analyzes a double-sided LC compensated CPT system systematically and finds an operating frequency to realize the load-independent constant current (CC) output and input zero-phase angle (ZPA) simultaneously. Without reactive power in the circuit, a design method is proposed to determine the compensation parameters and operating frequency using the given voltage ratings of coupler plates and compensation capacitors. Thus, voltage stresses among these capacitors could be optimized under their predesigned voltage ratings. The sensitivities of input impedance, output current to variations of compensation parameters are also discussed to realize soft switching. Finally, a prototype of the CPT converter with two types of proposed parameters and symmetric parameters is built to verify the analysis.