Characterization of Stator Winding Short-Circuit Faults in Interior Permanent-Magnet Motor-Drive Systems
This thesis contains a comprehensive analysis of experimental data collected from a case-study interior permanent-magnet electric machine experiencing winding short-circuit faults of varying severity. The experimental data collected from the faulted machine is from both motoring operation energized by a PWM sensorless ac drive as well as generating operation driven by the test bed dynamometer with a resistive winding load. For both modes of operation a complete set of three-phase voltage and current signals was recorded and analyzed. The three fault diagnosis techniques applied and compared regarding their ability to diagnose and prognosticate a winding fault in an interior permanent-magnet machine are motor current spectrum analysis (MCSA), negative sequence components analysis utilizing a symmetrical components transformation, and the space-vector pendulous oscillation method. The applicability of these diagnosis techniques to this case-study experimental interior permanent- magnet machine demonstrate that motor current spectrum analysis is inconclusive in diagnosing a winding fault when the machine is operated as a motor, but useful for diagnosing a winding fault when the machine is operated as a generator. Negative sequence components analysis successfully diagnoses the winding fault in both the motor operation and the generator operation cases. Finally, the space-vector pendulous oscillation method results are inconclusive for both the motor operation and the generator operation test cases.