Transient analysis of irreversible demagnetization of permenent magnet brushless DC motor with stator turn fault under the operating state

In this study, we investigate the irreversible demagnetization of a permanent magnet brushless DC motor under the stator turn fault conditions. We analyze the magnetic distribution property, input current, circulating current, and demagnetization characteristic of PM. For this transient analysis, we develop an FEM-based demagnetization algorithm under operating state, taking into account the circulating current flowing in the shorted turns and freewheeling current flowing in the diode. This analysis results from demagnetization algorithm are verified by performing an experiment.