Computer and experimental analysis of a reconfigurable staircase module-based multi-level inverter with fault tolerant capability.

In the conventional multilevel inverters, occurrence of a fault in one or more power switches can cause abnormal changes in the output waveforms. Besides, increasing the applied power switches results to an increase in the possibility of fault on the power switches. Accordingly, providing a comprehensive structure with high fault-tolerant capability is one of the vital requirements and critical challenges. To tackle these issues, this study first presents and explores a new basic unit and staircase module (SM) and then extends and optimizes it to yield a reconfigurable multi-level inverter (MLI) with more levels and different goals. The proposed MLI can continue to operate when open-circuit faults in switches. This advantage of the proposed structure is achieved without any redundant legs or switches. For further investigation, a comparison is made in terms of the number of power switches, drivers, dc sources, and reliability between the proposed and similar structures. To control the output voltage levels, the strategy of fundamental frequency switching triggers the configured topology. The carrier signals are reconfigured under fault conditions based on levels to be generated by bypassing the faulted switch. The validity of the established MLI with its fault-tolerant capability is certified through both computer simulations using the MATLAB/Simulink platform and laboratory prototype implementations.