Power Loss Analysis of Inverter with and without Transformer for Capacitive Power Transfer

This paper investigates the power loss characteristics in the circuit for the capacitive power transfer (CPT) system using analog circuit simulation focusing on the high voltage pulse generator with and without step-up transformer. The CPT usually has low capacitance value in their coupled capacitance due to the physical dimension and low dielectric constant of the interface, hence the high voltage with high-frequency switching needed to transfer the power through it. Using a simple LC resonant circuit and 1 MHz frequency operation, the power losses in inverter MOSFETs and transformer are analyzed under the condition with output power of 200W at 200Ω load resistance. The simulation results indicate that the inverter with step-up transformer with lower series resistance in both of wire strands can decrease the losses at MOSFETs with better efficiency compared to the high DC voltage supplied inverter without step-up transformer.