An Open-circuit Fault Diagnosis Method of H-Bridge Semi-Controlled Rectifier for DSEG Based on the Power Transistor Current

The H-bridge semi-controlled rectifier (HBSCR), with its advantages of high output power, short commutation time and low loss, has become one of the potential options for the controlled rectifier system of the doubly salient electromagnetic generator (DSEG). HBSCR is the weakest link of DSEG system, which will cause the fluctuation of the output voltage and decrease of the system load capacity after the open-circuit fault. Therefore, in order to improve the reliability of the DSEG system, it is important to study the open-circuit fault diagnosis method of HBSCR. This paper proposes a fault diagnosis method based on the power transistor current for single power transistor and dual power transistors open-circuit faults of HBSCR under the same conduction logic. First, the topology of HBSCR is redesigned. Then, the power transistor current combined with the driving signal is used as a fault signature. In addition, in order to avoid misjudgment during normal operation of the motor, the time threshold of fault diagnosis is analyzed and determined. The proposed method has a simple algorithm and is able to diagnose faults over an entire electrical angle cycle. Finally, the effectiveness of the proposed method is verified by simulation.