Radiated EMI Modeling and Performance Analysis of a PWM PMSM Drive System Based on Field-Circuit Coupled FEM

The radiated electromagnetic interference (EMI) behavior may have a negative impact on the machining accuracy of grinding machines. Therefore, this paper focuses on the radiated EMI generated by an ultra-precision pulsewidth modulation permanent-magnet synchronous motor (PMSM) drive system. The excitation for the radiated EMI model, the common-mode (CM) ground current at the output terminal of the converter, is obtained by simulating its conducted EMI model. The reasonable simplified FE models for the converter frame, the shielded power cable, and the motor frame are established. In addition, an equivalent circuit macro model of the CM impedance of the three-phase PMSM windings is obtained by using impedance measurements, the vector fitting method, and the fast residue perturbation method. Finally, the 3-D time harmonic field-circuit coupled finite-element method is employed to evaluate the radiated EMI.