Diagnosis of stator short-circuit faults in series and parallel winding connections of closed-loop controlled PMSMs

Stator winding short-circuit faults are among the most common faults that could occur in permanent magnet synchronous machines (PMSM). Therefore, on-line diagnosis of incipient stator winding short-circuit faults plays an important role contributing to the safe operation of PMSMs. However, the efficacy of known diagnostic methods varies with the types of stator winding configurations in PMSMs. This paper compares the effectiveness of diagnosis of stator winding short-circuit faults in series and parallel winding connections of PMSMs, with the same interior permanent-magnet rotor configuration. Two existing diagnostic methods have been applied to detect the severity of stator short-circuit faults happening in both series and parallel winding connection in PMSMs. Simulation analysis has been carried out in ANSYS Maxwell to compare the severity of magnetic saturation caused by equivalent short-circuit fault in series and parallel winding connected PMSMs. Experimental results lead to the conclusion that PMSMs with parallel winding connections can mask the influence of such stator short-circuit faults under certain circumstances, and thus it is more challenging to detect such incipient faults in parallel-winding-connected PMSM in comparison with series-winding-connected PMSMs.