Fault Protection Technique for ZSI-fed Single-Phase Induction Motor Drive System

Abstract

The Z-source inverter (ZSI) is getting popular for induction motor drives as it provides single-stage power conversion with voltage buck-boost ability. Recent surveys have reported that inverters are prone to failure due to internal faults on power semiconductor devices which significantly degrades the overall systems performance. The analysis and diagnosis of faults are significantly important for ensuring reliable operation of a drive systems. This paper rigorously analyzes effects of internal faults on a ZSI-fed single-phase induction motor drive system using MATLAB/Simulink. This study proposes a fault protection technique using bidirectional converter to facilitate post fault operation of inverter drives. The simulation circuits with the related harmonic spectrum are presented after introducing an open circuit fault and a short circuit fault in a drive system with and without a protection circuit. From systematic analyses it is found that fault occurrence leads to harmonic distortion to a significant level in the proposed drive system and therefore, affects the systems efficiency. The proposed fault protection technique proves to be an effective method to reduce harmonics in the drive system during a fault occurrence. THe FFT spectrum results are tabulated and compared.