Single and multi switch fault tolerant topology of multi level inverter

In applications using multilevel inverter topology, low reliability is one of the biggest concerns since a large number of semiconductor devices are used. Semiconductor devices are the weakest link in the power inverter system. Therefore, fault tolerance control becomes necessary where human intervention is least possible. In this paper, a novel topology is proposed which is fault tolerant to open switch faults and delivers power uninterruptedly. The fault tolerance has been achieved by adding additional but a minimum number of switches required. The proposed topology shows better results when compared with the recently proposed topologies. The switching scheme employed exploits the redundant paths in such a way that leads to the self-voltage balancing of the capacitors under healthy and faulty conditions. The validity of the proposed open switch fault tolerance is verified through simulation results.