Diagnosis and Locating Method for PMSM Interturn Fault Using Less Search Coils

Effective diagnosis of inter-turn fault (ITF) is crucial for ensuring motor reliability. Existing methods using search coils (SCs) have good diagnostic and locating performance, but they require a large number of SCs and have problems of complexity and high cost. Aiming at this issue, a novel online ITF diagnosis method, which require less SCs is proposed. The proposed method analyzes the SC fluxes generated by a single stator coil and estimates the healthy SC fluxes based on the stator currents. Then, the estimated SC fluxes are compared with the measured SC fluxes to determine whether ITF exists. Furthermore, the SC fluxes corresponding to the fault in each stator coil are analyzed, and the ITF is located by comparing it with the measured SC fluxes. Simulation and experiment results have shown that the proposed method can effectively diagnose ITF and locate the specific fault coil under different operating conditions and is unaffected by other motor faults. This method can reduce the number of SCs by 67%, effectively solving the problems of complexity and high cost of the traditional SC-based diagnosis methods.