Inverter Switch Fault Diagnosis System for BLDC Motor Drives

Safe operation of electric motor drives is of prime research interest in various industrial applications. This paper presents a new fault diagnosis system for open circuit switch faults in three phases Voltage Source Inverter (VSI) drive of the permanent magnet Brushless DC (BLDC) motors. The proposed fault diagnosis system is capable of detecting as well as identifying the faulty switch in the voltage source inverters. Faults diagnosis is based on Discrete Fourier Transform (DFT) analysis of the BLDC motor line voltages. Behaviour of the BLDC motor is analysed under open circuit faults of inverter switches through a validated simulation model. A knowledge based table is developed to identify the faulty switch by analysing the simulation results under various fault conditions. Performance of the BLDC motor is also investigated under open circuit faults of VSI switches through the experimental test rig. Experiment results validate the proposed inverter switch fault diagnosis algorithm for the BLDC motor drives.