Converter control effects on condition monitoring of rotor faults in permanent magnet synchronous machines

Motor current signature analysis is used to detect rotor faults in permanent magnet synchronous machines (PMSM) in this paper. Specifically, the effects of the speed-controller bandwidth (of the PMSM drive) in detecting these faults are examined. For instance, it is shown that the fault harmonics in the calculated electromagnetic torque waveform can be used to distinguish between a rotor fault and a varying load torque phenomenon. It is further shown that, depending on the value of speed-controller bandwidth, the fault harmonic information may be mostly in the stator current, mostly in the voltage, or distributed between both.