A fault-tolerant topology of T-Type NPC inverter with increased thermal overload capability

Reliability of multilevel power converters has received increased attention over the past few years, due to the relatively high component failure probability caused by the large number of switching devices utilized in the converter topologies. Thus, the fault-tolerant operation of multilevel converters plays an essential role in safety-critical industrial applications. This paper introduces an improved fault-tolerant inverter topology based on the conventional three-level T-Type neutral-point-clamped (NPC) inverter. Unlike other existing three-phase four-leg fault-tolerant inverter topologies, the fault-tolerant T-Type inverter topology proposed here can significantly enhance the overall thermal overload capability of the inverter, in addition to providing desired fault-tolerant capability. The operating principle of this proposed fault-tolerant T-Type inverter is detailed in this paper, and simulation results are presented to verify the advantages of this improved inverter topology.