A New Method to Estimate the Severity of Interturn Short-Circuit Fault for PMSM

This paper proposes a new method to determine the number of shorted turns for permanent magnet synchronous motor (PMSM). At first, the equivalent circuit model of PMSM under both normal condition and inter-turn short-circuit (ITSC) fault are presented. Then, the procedure to estimate the severity of ITSC in PMSM is introduced. In detailed, the stator winding of PMSM at standstill is excited by a low AC voltage, the corresponding current can be measured including its amplitude and phase, finally, the severity estimation indicator is established based on the electromagnetic parameters, including amplitude and phase of voltage and current, phase inductance and resistance. The effectiveness of the proposed method is verified by some simulations, which illustrates that the proposed method have good accuracy in the number of shorted turns detection in the range from the fault-free state to the full-winding fault state. The method proposed in this paper can be directly implemented without installing complex equipment and additional sensors on the motor, and it has utility value in the maintenance of PMSM.