Modeling of System-Level Conducted EMI of the High-Voltage Electric Drive System in Electric Vehicles

Abstract

Aiming at the problem of electromagnetic compatibility caused by the high-voltage electric drive system (HEDS) in electric vehicles, a model of the HEDS based on the vehicle is established to predict conducted electromagnetic interference (EMI) of the HEDS. First, the electromagnetic environment inside electric vehicles is analyzed theoretically. Then, the various parts of the HEDS are accurately modeled, which include the power buses, inverter, and motor. Based on the theory of multiconductor transmission line, a generic model of power buses suitable for two screening designs is presented. In order to accurately simulate the operating characteristics of the inverter, the drive circuit and the parasitic parameters of the dc-link capacitor block and the insulated gate bipolar transistor module are considered. The motor model takes into account the low-impedance antiresonance phenomenon in the measured motor impedance. Finally, the HEDS is simulated with PSPICE 16.6, and the simulation results agree well with the experimental measurements. The proposed model can accurately predict the system-level conducted EMI of the vehicle-mounted HEDS up to 100 MHz, with an error of 4 dB or less at almost all frequencies below 56 MHz and less than 7 dB at most frequencies in the 56–100 MHz.