An Accurate Common-Mode Voltage Reduction Method With Simultaneous Switching Frequency Minimization and Harmonic Mitigation

Common-mode voltage (CMV) is harmful to converter systems, thus actively suppressing the CMV is of great significance. To achieve accurate CMV amplitude reduction or complete CMV elimination using a low switching frequency, an improved switching frequency minimized harmonic mitigation (SFMHM) method is proposed in this article. Using the discrete voltage level as variables, the CMV can be accurately modeled using three-phase voltage variables, and its amplitude can be reduced or eliminated by properly setting the CMV constraint derived in this article. Then, the complete SFMHM model with CMV reduction and CMV elimination is presented, along with objectives as harmonic mitigation and switching frequency minimization. Comparative results are presented to show the superiority of the proposed method over the existing CMV reduction methods, and experimental results verify the effectiveness of the CMV reduction and elimination ability of the proposed method.