Reliability evaluation of a novel fault tolerant multilevel inverter with reduced components

Abstract

Safety–critical applications rely heavily on multilevel inverters. This article introduces a fault tolerant (FT) multilevel inverter sustaining an uninterrupted operation with an open switch fault occurred in a single and multiple power switches. Power semiconductor devices used in dc-ac converters increased in numbers to obtain high-quality voltage waveform which makes them vulnerable to failure. As a result, reliability is one of the biggest challenges in the utilization of multilevel inverters (MLIs) in many industrial applications. At the same time, reduced component multilevel inverters can achieve the highest resolution in output voltage waveform by compromising significant features (such as fault tolerance ability, charge balance control, etc.) but it is required to be preserved. For effective fault tolerant operation of MLIs, redundant switching states have given the highest priority in terms of switch level failures. A study is being undertaken to develop a novel fault-tolerant MLI, in the event of an open circuit fault on single and multiple switches. Therefore, the proposed FT-MLI structure can fulfill the operational requirement for a time being and claimed to be reduced components. A valid fault tolerant switching technique along with appropriate fault clearance is employed to obtain the desirable output voltage waveforms. In order to determine the feasibility of FT-MLI, performance evaluations are carried out based on results obtained under normal and abnormal operating conditions through the use of a laboratory prototype.