Modified H‐bridge inverter based fault‐tolerant multilevel topologyfor open‐end winding induction motor drive

Abstract

This study presents a three-phase modified H-bridge based multilevel inverter(MLI) topology for an open-end winding induction motor drive (OEWIMD). Theoperation of the proposed topology under open-circuit and short-circuit faultconditions of a switch is investigated. Proposed MLI topology is designed withthree three-phase modified H-Bridge inverters connected in a star configurationto feed an OEWIMD. This topology has advantage of delivering a maximum voltageof twice the supply voltage and is replicated as nine levels in the phasewindings of OEWIMD, thereby reducing the total harmonic distortion. Therefore,lower voltage rating sources such as solar cells or fuel cells can be used forthis topology. This topology becomes cost effective since the operating voltagerange required for the devices is less. Controlling methods such as conventionallevel-shifted and multi-reference sinusoidal pulse width modulation techniquescan be applied for this topology. A fault-tolerance strategy is proposed forinverter switch open-circuit and short-circuit faults that adds fault-tolerancecapability to the proposed topology. Simulations were performed usingMATLAB/Simulink and experimental results are presented for both normal operatingand fault-tolerance mode that confirms the inherent fault-tolerance property ofthe proposed MLI topology.