Fault Diagnosis of Power Transistors in Switched Reluctance Drives Based on Cumulative Sum of Current Relations

Fault diagnosis of power transistors is essential to enhance the reliability of switched reluctance drives (SRDs). In this article, a fault diagnosis scheme for power transistors is proposed for SRD based on the cumulative sum of current relations. First, a new installation method for current sensors (CSs) is presented to obtain more current information without increasing the number of CSs. Meanwhile, a simple algebraic formula of the phase current is derived during normal and faulty situations. Next, the implementation principles of the proposed fault diagnosis scheme are presented. Based on the digitization characteristic value of current relations and the cumulative sum of current relations, the single-transistor and two-transistor faults can be effectively diagnosed online. Meanwhile, the application analysis of the proposed scheme is carried out for different chopping modes and control strategies. Finally, experiments on a four-phase 8/6 SRD system were conducted to verify the validity of the proposed fault diagnosis scheme.