Simplified Space Vector PWM Algorithm for Multilevel Inverters Using Non-Orthogonal Moving Reference Frame

This work proposes a simplified space vector PWM algorithm for multilevel inverters using non-orthogonal moving reference frame. In this strategy, the non-orthogonal reference frame rotates accordingly with the sector where the reference vector lies. The nearest three vectors (NTV) are determined via identification of the triangle in hexagon, using information about the sector and the triangle where the reference vector lies. The duty-cycles are determined using a single calculation equation set. Therefore, the logic tests used by formerly proposed algorithms to determine the NTV and to calculate the duty-cycles are no longer necessary. The calculation of triangle location and duty-cycle considering the NTV are simple. The switching pattern is generated via the selection of coefficients stored in look-up table. The approach works for any number of levels, and its great advantage is that the complexity of the algorithm no longer increases, close to cubically, with the number of the inverter levels. Simulation and experimental results shows the algorithm feasibility.