Demagnetization faults analysis in a BLDC motor for diagnostic purposes

This paper investigates a surface inset-permanent magnet brushless DC motor with fractional-slot winding configuration driven by a three-phase inverter under different types of defected magnets. The comparative study on demagnetization faults is carried out using FEM analysis. The number of damaged magnets, their relative position in the rotor surface and their demagnetization level are studied for diagnostic purposes. The harmonic components of the stator current and torque spectrums are considered as diagnostic means of the demagnetization faults. The influence of different types of demagnetization faults on the electromagnetic behavior of the BLDC motor is also investigated exploiting FEM analysis.