An Improved PWM Method for Minimum Common-Mode Circulating Current Operation of Six Phase Three Level Inverter

This paper presents a simple Pulse Width Modulation (PWM) technique to reduce the common-mode circulating current of a six-phase three-level inverter. Six-phase inverters generally suffer high common-mode circulating current when space vector PWM (SVPWM) or min-max method is used with a common neutral point. For common-mode circulating current reduction, Phase Disposition (PD) PWM with a compromised third harmonics injection method is proposed in this work. The selected third harmonics injection method removes the low-frequency common-mode circulating current. The absence of low frequency circulating current improves the THD of the load currents. Finally, the proposed method is tested in PLECS simulation with a 75KW system, and results are presented here.