Reliable Operation of an Asymmetrical Multilevel Inverter Topology

A reliable multilevel inverter topology with asymmetrical source configuration to sustain switch open circuit faults is proposed in this paper. Under normal operation, with 3:1 ratio of source configuration, the proposed inverter develops 9levels voltage output. The most common faults in semiconductor switches are open circuit faults and also fault in gate driver is treated as an open circuit fault in switch due to a cease in pulses to the corresponding switch. So, this paper analyzes for open circuit faults in switches. The voltage levels and magnitude are fallen for fault in certain switches and connecting a tap-changing transformer at the output maintains the peak voltage magnitude. But, load scheduling is necessary to ensure continual operation of the inverter. The circuit is operated using Nearest Level Control (NLC) technique. The proposed circuit is simulated in MATLAB/SIMULINK and is validated using a developed prototype.