A multilevel converter topology with fault-tolerant ability

A new topology with fault-tolerant ability that improves the reliability of multilevel converters is proposed. This new topology is developed through analysis of different power device´s failure modes. With the proposed scheme, the function of the power stage can be maintained even part of it fails. Its fault-tolerant ability results from the redundant nature of the multiswitching-state topology and from control signal modification. Furthermore, it balances the voltage levels automatically without any assistance from other circuits. The validity of the proposed scheme is confirmed by experiments in a five-level single-phase inverter prototype.