The FDTD Analysis of EMI in Motor Drive System

In motor drive system, the high dv/dt and di/dt due to the fast switching of IGBT could bring serious EMI (electromagnetic interference) issue. This paper proposes an EMI analysis method which combines with the test and simulation based on finite-difference time-domain (FDTD). The excitation source of FDTD is obtained by testing EMI of drive system and is added the input of simulation system, then the EMI coupling path is analyzed. On the one hand, EMI has many frequency spectrums, which computes wide-band S parameter. On the other hand, the method is of practical significance for analyzing EMI inside different system because the excitation source signal derives practical drive system. This paper analyzes the EMI of PWM drive system and puts forward the algorithm principle of FDTD based on EMI. The error of simulation and experiment results is less than 10dB. Simulation and experiment results are presented to indicate validity of the proposed method