A reliable multilevel inverter with fault tolerance

A reliable multilevel inverter with fault tolerance is proposed. It consists of two sources and six switches. The unipolarity voltage level produced by the proposed inverter is transformed to dual polarity with the help of H-bridge. The proposed inverter produces maximum 9 levels output voltage with asymmetrical source and 5 levels output voltage with symmetrical source in healthy condition. During any fault in the inverter, it continues to operate with reduced voltage levels. The various modes of operation of the circuit are explained with all possible open circuit switch fault. Variable frequency inverted sine carrier PWM switching technique is implemented to verify the circuit operation. The comparative graph of level count vs switch count is provided. The proposed circuit provides uninterruptible operation during fault condition which increases the reliability of the circuit. It is simulated with MATLAB SIMULINK and the results are provided for the validation.