Methods to identify intermittent electrical and mechanical faults in permanent magnet AC drives based on wavelet analysis

Prognosis of failures of electric drives can be achieved through the detection of non-catastrophic faults. As the frequency and severity of these faults increase, the expected working life of the drive decreases, leading to eventual failure. In this work, a method is presented to identify developing electrical and mechanical faults based on analysis of the undecimated discrete wavelet transform of the field oriented currents in PMAC drives. Linear discriminant analysis is used to classify between the fault types.