Modified H-bridge inverter based fault-tolerant multilevel topology for 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). The operation of the proposed topology under open-circuit and short-circuit fault conditions of a switch is investigated. Proposed MLI topology is designed with three three-phase modified H-Bridge inverters connected in a star configuration to feed an OEWIMD. This topology has advantage of delivering a maximum voltage of twice the supply voltage and is replicated as nine levels in the phase windings of OEWIMD, thereby reducing the total harmonic distortion. Therefore, lower voltage rating sources such as solar cells or fuel cells can be used for this topology. This topology becomes cost effective since the operating voltage range required for the devices is less. Controlling methods such as conventional level-shifted and multi-reference sinusoidal pulse width modulation techniques can be applied for this topology. A fault-tolerance strategy is proposed for inverter switch open-circuit and short-circuit faults that adds fault-tolerance capability to the proposed topology. Simulations were performed using MATLAB/Simulink and experimental results are presented for both normal operating and fault-tolerance mode that confirms the inherent fault-tolerance property of the proposed MLI topology.