Comparative Analysis Between Three-Phase Five-Level Inverter and Nine-Phase Two-Level Inverter

Three-phase multilevel converters are the main existing solution for high power motor drives. Using multilevel cells in a cascaded converter enables associating low-voltage devices for reaching higher voltages with less complex transformer. An alternative solution for high power applications is using multiphase converters, since the output power of the converter increases proportionally with the number of phases, besides another advantages: higher reliability and possibility to operate under open phase fault. The present paper aims to compare two converters topologies. The first is a three phase five-level H-bridge NPC converter, and the second is a nine-phase two-level converter. The converters are compared by voltage and currents waveforms, maximum output power per power module, efficiency and costs.