Reconfigurable Multilevel Inverter With Fault-Tolerant Ability

Abstract

The cascaded H-bridge multilevel inverter (CMI) is one of the most popular converters, especially in renewabale energy applications. Beyond offering some significant benefits, this inverter suffers from the drawback of employing great number of components which reduces the reliability of the inverter. Thus, designing a scheme to enhance reliability in this kind of inverter is of crucial importance. In this paper, a fault-tolerant structure for the cascaded H-bridge multilevel inverter is designed. Failure rates of the switches and diodes are calculated. Then, by using the Markov method, reliability and mean time to failure (MTTF) of the mentioned inverter, before and after employing the suggested scheme, are evaluated. In order to prove proper performance of the suggested scheme, a laboratory built prototype is employed. The results show that employing the suggested scheme significantly enhances reliability and MTTF of the inverter.