Fault detection and fault-tolerant operation of a seven-level inverter

Applications of multilevel inverters (MLIs) are increasing extensively. Despite many advantages of MLIs, poor reliability of MLIs is a major concern as MLIs consist of a large number of semiconductor switches. Fault-tolerant topologies provide the solution to this problem. In this paper, a fault detection and identification method is presented for a sevenlevel fault-tolerant inverter. This fault detection method is based on monitoring the total harmonic distortion (THD) in output voltage and average voltage of one cycle. After identification of the faulty switch, the switching sequence and switching angles are to be adjusted. The method of fault detection and identification is verified by simulation results.