Impact of Common-mode Circuit on Variable Switching Frequency PWM Strategy in Voltage Source Inverters

In this paper, a typical NPC three-level voltage source inverter (VSI) is selected, and the main objective is to study the influence of common-mode (CM) circuit on current ripple prediction, which is an important basis for variable switching frequency PWM (VSFPWM) design. Furthermore, to highlight the impact of CM voltage distortion on current ripple, this paper investigated the SVPWM and the CM elimination PWM (CMEPWM) for a NPC three-level inverter. Detailed experimental comparisons are carried out, and some useful conclusions are listed.