Modeling approach and fault index analysis of a voltage-source brushless DC motor

Abstract

This paper presents a modeling approach and a fault index analysis of a voltage-source brushless DC motor. First, an analytical multi-physical model of the inverter-fed Permanent Magnet DC motor is developed and simulated using Matlab/Simulink. This model enables the generation of electrical, magnetic and vibration signals under healthy and faulty motor behaviors, with several fault categories and severities. Before simulating faulty conditions in the different parts of the analytical model, they are compared to Finite Element models, developed using Matlab for air-gap flux density and ANSYS software for stator natural frequency calculations. Simulation results of the motor during normal functioning and under faulty conditions are presented. In particular, rotor eccentricity and single pole demagnetization faults are studied in this paper. Then, different features, including time-, space-, frequency-and harmonic-domain characteristics, are extracted from vibration signals for different cases. Finally, these indicators are analyzed with respect to the fault severity to select the most discriminative one(s) allowing an efficient fault detection and isolation.