Optimal Design Method of High Voltage DC Power Supply EMI Filter Considering Source Impedance of Motor Controller for Electric Vehicle

Abstract

Passive filters are often used for electromagnetic interference (EMI) suppression on the high voltage (HV) DC side of motor drive systems due to their simple structure and large noise suppression. However, the traditional passive filter design method takes less consideration of the change of the system source impedance, which will lead to almost no insertion loss in some frequency bands or an over-design of the filter. Based on the onboard working conditions of high-voltage and high-current, this article adopts the dual current probe method to obtain the source impedance of the system when it is working, and proposes a filter multi-objective optimization design method based on the genetic algorithm (GA). This method automatically selects the optimal topology of the filter and related component parameters according to the source impedance and load impedance, avoiding the filter resonance phenomenon and over-design problems caused by not considering source impedance. The experimental results show that conducted interference voltage and current of motor drive system with filter designed by the proposed method can pass CISPR25-2016rd level 3.