Space vector modulation of multilevel inverters: a simple and fast method of two-level hexagon's selection

Abstract

A commonly used technique to implement the Space Vector Pulse Width Modulation (SVPWM) algorithm of multilevel inverters is based on identifying at any sampling time the appropriate two-level hexagon enclosing the output voltage space vector. The identification method proposed in this paper is based on finding the smallest distance between the reference vector tip point and the center of (n − 1 / 2)2 two-level hexagons covering an entire sector, where n is the number of levels. The effectiveness of this method is confirmed by computer simulations carried out on a numerical model of a five-level Neutral-Point Clamped (NPC) inverter. The obtained results show the high quality of voltages and currents waveforms and reduced common mode voltages (CMV). It was also shown that the real-time computation burden on a Digital Signal Processor (DSP) is less important than the one of a former algorithm using a different identification approach of the appropriate two-level hexagon.