Study on Parasitic Capacitance Effect in High Power Inductive Power Transfer System

Abstract

This paper reveals the parasitic capacitance effect in high power inductive power transfer (IPT) coil, and indentify its impact on conductive common mode noise. Both analytical calculation and FEM simulation method are used to estimate the parasitic capacitance value, and a CM noise model of IPT system is proposed to evaluate the impact of parasitic capacitances in the inductive coils. The result shows that the stray capacitance between IPT transmitter coil and metal-shielding layer is significant and plays dominant role in CM noise propagation path. Circuit simulation and experimental validation with an 11kW IPT prototype are conducted to verify the model accuracy. This paper provides an analysis method of parasitic capacitances in IPT coil and the guideline of conductive common mode EMI design for high power IPT system. The future work aims to find various methods to suppress the severe CM noise induced by parasitic capacitances.