Analysis and Design of Double-sided LCLC Compensation Parameters with Coupling-insensitive ZVS Operation for Capacitive Power Transfer

The aim of this paper is to present a parameter design method that can realize zero voltage switching (ZVS) even if the coupling capacitance varies in capacitive power transfer (CPT) applications. The equivalent circuit model considering both the conduction losses of passive components and the switching losses of power switches in a CPT system is established. The ratio of the switching loss to the output power at different frequencies is quantified. By deriving the analytical solution of the current at the switching instant of the inverter, it is found that the series-compensated inductor can be carefully designed to fulfil the ZVS condition in a wide operation range. The parameter design procedure is summarized accordingly. A 1 MHz CPT prototype with up to 1.4kW output power for electric vehicles (EVs) is built to verify the validity of the method.