A simple multi-level space vector modulation algorithm for five-phase open-end winding drives

Three-phase open-end winding variable speed drives with dual-inverter supply have been extensively investigated for various applications, including series hybrid powertrains and propulsion motors. The topology is simple to realise while offering a higher number of switching states without the need for capacitor balancing algorithms, when compared to standard multi-level converters. There are very few works which consider the use of multi-phase machines in such topologies. One of the reasons for this is that inclusion of a multi-phase machine leads to exponential increase in the number of possible switching states and so the design of a suitable space vector modulator (SVM) represents a considerable challenge. This paper considers a five-phase open-end winding drive and proposes a relatively simple SVM algorithm, based on the already well understood five-phase two-level drive SVM method. The proposed modulation technique has the advantage of being straightforward to implement and, like its two-level counterpart, is able to generate output voltages with minimum low-order harmonic content. The method generates up to seventeen-level output phase voltage and therefore offers superior harmonic performance when compared to the two-level five-phase topology. The developed scheme is verified via simulation including the dynamic performance of the five-phase machine operating under V/f control and experimentally using a passive load.