A simple space vector PWM scheme with neutral point balancing for three-level neutral point clamped inverter

Abstract

Three-level neutral-point diode-clamped (NPC) multi-level inverter has been known as a superior topology of inverters. However, this topology method has an inherent problem of the neutral point potential variation. In this paper, a simple control scheme based on the unified voltage modulation technique has been proposed to balance the neutral-point voltage of three-level NPC inverter. The proposed scheme has been achieved by the calculated off-set voltage including the neutral point balancing factor. The neutral point fluctuation can be simply compensated without additional efforts and easily applied to the unified voltage modulation. The validity of the proposed scheme has been proven through the simulation and experiments results.