Detection of Stator Interturn Short-Circuit Faults in Inverter-Fed Induction Motors by Online Common-Mode Impedance Monitoring
Zhenyu Zhao, Fei Fan, Wensong Wang, Yong Liu, Kye Yak See
Abstract
By monitoring the online common-mode (CM) impedance of an inverter-fed induction motor (IM) through an inductive coupling technique at a specific frequency of interest (FOI), the stator interturn short-circuit (ITSC) faults of the IM can be detected with good confidence. The inductive coupling technique is adopted because it monitors the CM impedance of the IM without a physical electrical connection, which eliminates electrical safety hazards and facilitates ease of implementation. Using a 1/2-hp squirrel-cage IM as a test case, it has been demonstrated that the proposed method is sensitive to the stator ITSC faults but invariant to motor load and speed variations, as well as bearing and rotor faults, making it highly reliable and robust for stator ITSC fault detection.