Research on Interturn Short-Circuit Fault Indicators for Direct-Drive Permanent Magnet Synchronous Motor

In this article, the effects produced by interturn short-circuit faults (ISFs) on variables of the direct-drive permanent magnet synchronous motors (DDPMSMs) are investigated. A finite-element method model is established to calculate the motor variables of DDPMSM that includes average torque, second-harmonic torque, torque ripple, branch differential current, branch residual current, branch voltage, and so on. Then, the motor variables under different cases, including various fault conditions and various operating conditions, are analyzed to understand the effects of ISF. Besides, the fault indicators (FIs) are selected based on the analysis of ISF. Finally, the simulation and experimental results are compared at different fault conditions and operating conditions to fully verify the analysis of ISF and FIs. This work provides a significant reference for the fault diagnosis, fault postprocessing, and fault-tolerant control of DDPMSM.