A novel neutral point potential stabilization technique using the information of output current polarities and voltage vector

Abstract

This paper proposes a new neutral point potential control technique for the three-level neutral-point-clamped PWM inverter. Utilizing the phase current polarity information, this technique distributes the redundant voltage vectors in a manner to obtain stable neutral point voltage under all operating conditions including the zero power factor condition. Detailed analysis and computer simulations show the superiority of the proposed method. The feasibility of the proposed method has been proven via laboratory experiments.