Neutral-Point Potential Balancing Using Synchronous Optimal Pulsewidth Modulation of Multilevel Inverters in Medium-Voltage High-Power AC Drives

Abstract

This paper presents neutral-point potential (NPP) balancing while maintaining low harmonic distortion using optimal pulsewidth modulation (PWM) of a multilevel inverter for medium-voltage high-power industrial ac drives. This method is applicable for five-level inverters or higher. A high performance of the machine is observed experimentally at low-switching-frequency operation employing the proposed technique. In the past, low distortion and optimal common-mode voltage at low-switching-frequency control have been reported using proposed synchronous optimal PWM.