Current Sensor Fault Localization and Identification of PMSM Drives Using Difference Operator

The permanent magnet synchronous motor (PMSM) has received increasing attention in traction applications. For those closed-loop control systems, the current sensor is one of the most sensitive components, which determines the control performance and safety operation. Therefore, the fault diagnosis of current sensors is of great importance to realize fault tolerance and further maintenance. In this work, a novel fault localization and identification method of the current sensor is proposed for PMSM drives. The residual between the measured current and estimated currents based on a modified $\alpha \beta $ reference frame is employed for the fault sensors’ localization. Besides, a second-order difference operator is adopted to identify the fault types. Moreover, a function is defined for preventing misdiagnosis, thus enhancing the algorithm’s robustness. The algorithm for the fault type identification would not be affected by the variation of motor parameters, granting it high flexibility to combine with not only the fault location algorithm in this article but also with other model-based methods. The effectiveness of the proposed approach is experimentally validated on an 11-kW platform of the PMSM fed by a three-level T-type inverter.