Contents I. Introduction
The early and correct diagnosis of a failure in an electrical drive ensures optimum reliability, maximum safety, timely maintenance, and preventive rescue of electric motors in both low- and high-power applications. Numerous methods have been developed in the last 15 years to detect faults in electric drives. The types of machines that have been investigated included induction machine [1]–[10], permanent magnet ac machine [11]–[26], and permanent magnet brushless dc machine [27]–[31]. Among ac machines, interior permanent-magnet (IPM) synchronous motors are attractive for a variety of applications because of their high electromagnetic torque per permanent magnet volume, high efficiency, high power factor, low noise, and relatively low cost [32]–[34]. However, the IPM motors are subjected to a wide variety of abnormal operations including faults. These faults create special challenges for a permanent magnet synchronous motor (PMSM) itself because of the presence of spinning rotor magnets that cannot be turned-off during faults. Thus, it is important to understand the responses of an IPM motor to any potential fault condition in order to prevent fault-induced damages in the drive system containing load.
