A comparison of three-level single-sided and dual-inverter supply for a five-phase drive

Multiphase multilevel topologies are considered promising since they combine the already recognised benefits of the individual use of both a larger number of phases and a higher number of voltage levels. There are two conceptually different ways of achieving three-level operation with a multiphase load - by applying a three-level inverter to a star connected machine or by applying two two-level inverters at the two sides of the machine. This paper examines the behaviour of these two supply topologies by applying the same modulation method to both solutions. For the sake of simplicity, a carrier-based modulation is chosen. However, the space vectors that are applied by the method are investigated as well. The selected modulation method is the one that gives the smallest amount of voltage and current distortion throughout the linear modulation index range. The comparison is based on experimental results collected from laboratory prototypes of the two supply systems, in conjunction with a five-phase induction motor drive system.