A multilevel converter topology with fault tolerant ability

A new topology with fault tolerant ability is proposed to improve the reliability of multilevel converters, which is based on the analysis of different power devices failure modes. With the proposed scheme, the function of the power stage can be maintained even part of it fails. The fault tolerant ability is resulted from the inherent redundant nature of the multiswitching-states topology and control signals modification. Further more, the topology balances the voltage levels automatically except for achieving fault-tolerance. The validity of the proposed scheme is confirmed by experiments in a five-level inverter prototype.