Secondary-Fault Diagnosis of Rotating Rectifier in Brushless Wound-Rotor Synchronous Starter-Generator Based on Estimated Rotor Currents

Fault diagnosis of the rotating rectifier in brushless wound-rotor synchronous starter-generator (BWRSSG) plays an important role for improving the reliability of the aircraft BWRSSG system. After an open-circuit fault of the rotating rectifier, the BWRSSG system can still operate at derated status, and in this case, it is necessary to continue to conduct fault diagnosis for the other healthy diodes of the rotating rectifier, namely the secondary-fault diagnosis. By analyzing the average-value features of the rotor currents of the main exciter (ME) under different fault conditions of the rotating rectifier, a secondary-fault diagnosis method for the rotating rectifier based on estimated ME rotor currents is proposed in this article. In this method, ME rotor currents are estimated first, and then combined with the location information of the first open-circuit fault, average values and their ratio of the ME rotor currents are calculated and used to detect the fault occurrence, fault location, and fault type of the secondary-fault for the rotating rectifier. The proposed method can be easily implemented in practical applications, and experimental results verified the feasibility and effectiveness of the proposed method.