A New Single-Phase Fault-Tolerant T-Type Five-Level Inverter with 100% DC Utilization

The paper presents a new single-phase fault-tolerant five-level inverter with 100% DC utilization. Self-balancing of dc capacitors with reduced device counts and compact T-type structure will enhance the overall reliability of the proposed topology. A simple half-bridge circuit with two additional semiconductor devices were added to the topology to obtain more redundant states which can support the five-level generation under most of the fault conditions. Moreover, the waveform quality and the power handling capability is ensured under various open/short circuit fault conditions of the proposed topology with the help of redundant switches and modified pulse width modulation scheme. Further, reduced device count and minimum number of conducing devices in each cycle ensure the highest efficiency with its counter parts. The proposed circuit is tested through MATLAB/Simulink environment for various open circuit fault conditions and the results are presented. Finally, a comprehensive comparison is made to highlight the merits of the proposed topology.