Modeling of conducted EMI with current probe method for a motor-drive braking system

In this paper, a modeling method for predicting the conducted emission with a current probe method is presented for a motor-drive braking system. The proposed model considers the motor driving circuit components and the measurement environment. The models of motor driving circuit component include PWM inverter circuits, 3-phase motor, PCB, heatsink, bus bars, and motor casing. The models of measurement environment involve the current probe, test table including ground plane, harness cable, and LISN. To reflect the accurate path of common and differential mode current of the motor drive system, co-simulation is proposed with the equivalent circuit and SPICE model. Co-simulation is eventually conducted by using EMC Studio of EMCoS Ltd. for the calculation of electromagnetic coupling around the circuit, and the high-frequency parameters of the motor driving circuit are calculated through ANSYS Inc.'s Q3D. For the model validation, the measurement and simulation results are compared, and the results of the conducted emission of those agree well in the range of 100 kHz up to 108 MHz.