Open-Circuit Fault Diagnosis of Rotating Rectifier by Analyzing the Exciter Armature Current

Based on the differences between waveforms of asynchronous exciter three-phase armature currents with the rotating rectifier under various working conditions (healthy and open-circuit conditions), a fault diagnosis method of rotating rectifier is proposed in this article. To describe these differences, the conceptions of ratio, residual, and sum are defined, and corresponding calculation functions are created. Through the analysis of the asynchronous exciter armature current with the rotating rectifier under five categories of working conditions, three-phase ratios and residuals are calculated by observing which the fault type can be confirmed. Then the faulty diode(s) location is achieved by the sum value. The experimental results show good agreement with theoretical analysis and simulation results, which verifies the feasibility and effectiveness of the proposed method.