Common Mode Voltage Elimination and Conducted EMI Reduction for Two-Unit PMSM

Two-unit permanent magnet synchronous motor (PMSM) is widely used due to its high power and high fault tolerance. When pulse width modulation (PWM) is used in motor drive systems, common mode voltage (CMV) will be generated. The conducted electromagnetic interference (EMI) of the system is enhanced as a result, affecting the normal operation of the system. For two-unit PMSM driven by two parallel inverters, this article proposes a modulation strategy that can completely eliminate CMV. The proposed strategy aims to suppress conducted EMI by reducing the common mode leakage current in the system. The principle of the proposed strategy is briefly introduced, and experimental results of conducted EMI under different strategies are presented. The effectiveness of the proposed strategy is verified through the comparison of experimental results.