A Novel Multifault Diagnosis Method for SRM Drives in Electrified Powertrains

Switched reluctance motors (SRMs) are recognized as a promising technology for electrified transportation due to their fault-tolerant and rare-earth free features. In transportation applications, particularly in powertrains of the railways and aircraft, the reliability of every component in the motor drive system is of paramount importance. Existing state-of-the-art diagnostic approaches address faults in each component separately, leading to increased system complexity. Therefore, a single algorithm for real-time diagnosis of multiple component faults becomes an attractive solution. This article presents a simple yet comprehensive technique for detecting and locating nearly all potential electrical faults and current sensor faults in SRM drives at their earliest stages. The proposed diagnostic scheme can effectively identify ten failure cases, including open-circuit and short-circuit faults in power switches, power diodes, phase winding open-circuit faults, and zero-output current sensor faults. Fundamental current and modified dc-bus currents are used for developing fault features, thereby avoiding additional costs and complexity. Digital logic judgments are developed based on the measured currents for fault localization. Simulation studies and rigorous experiments are conducted on a three-phase 12/8 SRM drive system to validate the feasibility and superior performance of the diagnostic scheme.