Finite-Element Analysis of the Demagnetization of IPM-Type BLDC Motor With Stator Turn Fault

This paper investigates the dynamic demagnetization characteristics of an interior permanent magnet (PM) brushless dc motor with a stator turn fault (STF). A new algorithm, which is a finite-element method combined with a line voltage equation of the motor, is developed to analyze demagnetization under dynamic and transient states and considers an STF. The input current, circulating current, magnetic distribution characteristic, and operating property of the PM, including the irreversible demagnetization in the fault state, are analyzed using this algorithm by considering the magnetic saturation effect. The feasibility of the proposed method confirmed from the analysis results is verified via an experiment. Through this fault analysis, we can accurately check the fault phenomena and healthiness of a PM motor against the demagnetization fault for fault prevention.