A novel carrier based PWM method in three phase four wire inverters

This paper presents a new carrier based PWM method to control the three phase four wire inverters. An equivalent circuit model of two-level inverter has been proposed, presenting a redundancy function in the zero sequence voltage. Its application has been used to explain simply the characteristics of the three phase four wire inverter topologies. The advantage from this method is a simple and flexible PWM control, and its possible applications to higher level inverters. Several specific characteristics have been also introduced.