Power Converter Fault Detection and Isolation Using High-Frequency Voltage Injection in Switched Reluctance Motor Drives for Automotive Applications

Exceptional robust configuration and fault tolerance capabilities make switched reluctance motors (SRMs) a promising technology for automotive applications. Nevertheless, the power transistors in a power converter of an SRM drive are well-considered more vulnerable, compared with the SRM itself. Therefore, accurate and early stage fault detection is crucial for such safety-critical applications. This article investigates the usage of high-frequency (HF) signal injection for real-time fault identification and localization of power transistors in SRM drives. Unlike the existing diagnostic schemes that often use extra current/voltage sensors and complex algorithms, this simple method injects a sinusoidal HF voltage signal into a standard asymmetrical half-bridge converter-fed SRM. Finally, the induced HF current is filtered from the fundamental current, and its frequency is estimated in real time for fault localization. Typical power transistor faults (open circuit and short circuit) and their location can be effectively detected in the earliest stage by monitoring the variations in the filtered HF signal as well as the fundamental current with the occurrence of the faults. The effectiveness of the proposed diagnostic strategy is validated by thorough simulation and experimental results carried out on a three-phase 12/8 SRM drive system.