Three phase three-level PWM switched voltage source inverter with zero neutral point potential

Abstract

A new three phase three-level pulse width modulation (PWM) switched voltage source (SVS) inverter with zero neutral point potential is proposed. It consists of three single-phase inverter modules and each module is composed of switched voltage source and inverter switches. The major advantage is that the peak value of the phase output voltage is twice as high as that of the conventional neutral-point-clamped (NPC) PWM inverter. Thus, the proposed inverter is suitable for application with low voltage source such as battery, fuel cell, and solar cell. Furthermore, three-level waveforms of the proposed inverter can be achieved without switch voltage unbalance problem. Since the average neutral point potential of the proposed inverter is zero, the common ground between input stage and output stage is possible. Therefore, it can be applied to transformer less power conditioning system (PCS). The proposed inverter is verified by the PSpice simulation and experimental results based on a laboratory prototype.