Five Level Modified CHB Inverter with Switch Level Redundancy

Multilevel inverters have become increasingly important in medium to high power applications due to their ability to produce high-quality output voltage with reduced harmonic distortion and lower electromagnetic interference. Among the various multilevel inverter topologies, the cascaded H-bridge (CHB) inverter stands out for its modularity, scalability and potential for fault tolerance. This paper presents a five-level modified CHB (MCHB) inverter topology incorporating redundancy to enhance reliability, fault tolerance and power quality. A device level redundancy is deployed for fault tolerance against open switch fault. For identification of faults, RMS and average value of output voltage of inverter is measured continuously and compared with threshold levels. MATLAB simulation results are presented to demonstrate the fault tolerant operation with redundancy. The system was observed to respond to the fault and restore normalcy within single cycle.