On-Line Fault Diagnosis for Rotating Rectifier in Wound-Rotor Synchronous Starter-Generator Based on Geometric Features of Current Trajectory

Accurate and timely fault diagnosis of the rotating rectifier in wound-rotor synchronous starter–generator (WRSSG) plays an important role in improving the reliability of the WRSSG system. By analyzing the geometric features of the rotor current trajectory of the main exciter (ME) under health and different fault conditions of the rotating rectifier, in this article, a fault diagnosis method for the rotating rectifier based on the geometric features of ME rotor current trajectory is proposed. In this method, ME rotor currents are estimated first, and then the center distance, center angle, and length–width ratio of the ME rotor current trajectory are calculated and used to detect fault occurrence, locate the faulty diode, and identify the fault type for the rotating rectifier, respectively. The experimental results verified the feasibility and effectiveness of the proposed fault diagnosis method.