Open-Switch Fault Tolerance Capabilities of Some Reduced Device Count Multilevel Inverter Topologies

In this paper, some of the recently proposed reduced device count multilevel inverter (RDC-MLI) topologies are considered and analyzed in the light of imparting “any switch” open circuit fault tolerance capability. In RDC-MLIs, the occurrence of faults would shut down the system due to the lack of redundant switching states. However, for the cases involving “any single switch open circuit fault,” the system can continue to operate uninterrupted. This is achieved by adding redundant states of switching combinations, obtained by addition of switching device(s). By the proposed solution, the complete system shutdown can be prevented, thereby attaining higher reliability in RDC-MLIs. Further, the modified systems under normal and faulty conditions have been simulated using MATLAB/Simulink environment and the results are experimentally validated to prove the feasibility of the strategy for imparting fault tolerance to RDC-MLIs.