Implementation of a fast and simple space vector modulation scheme for a three-phase five-level neutral point clamped inverter

Multilevel inverters are nowadays considered among the most promising power conversion topologies for medium voltages and high power ranges. This work presents a fast space vector modulation algorithm (SVPWM) implemented on a three-phase five-level neutral point clamped (5L-NPC) inverter. The novelty of the proposed algorithm deals with the identification method of the adequate two-level small hexagon. This method computes the distance between each small hexagon center and the tip point of the reference space vector to be synthesized by the modulation algorithm. Therefore, the selected small hexagon is the one which has its center closest to the reference vector tip point. The remaining procedures needed to obtain the switching sequences of the transistors´ gates are quite similar to those utilized by previous SVPWM algorithms. Computer simulations performed on a numerical model of the converter showed the effectiveness of the proposed identification method.