Modeling and Estimation for Conducted Common-Mode Interference of a Motor Drive System Used in Electric Vehicle

Motor drive system in an electric vehicle (EV) connects both low voltage (LV) bus and high voltage (HV) bus. Since the vehicle's communication, lighting, instrumentation and vehicle control system, etc. are all powered by LV power supply, the interference level at the low voltage power port of the motor drive system has a significant influence on the operation of EV. This paper studies the interference coupling mechanism between the HV and LV circuit in an EV motor drive system, establishes the interference equivalent circuit to estimate the common mode conduction interference level on the LV power supply port. This research lays a foundation to attenuate the emission of conducted interference from motor drive system to the LV power supply system of EV.