Open Circuit Fault Diagnosis of Rotating Rectifier based on the Polarity and Symmetry of Armature Current

Based on the differences among polarity and symmetry of asynchronous exciter's armature current in various cases (healthy and faulty conditions), a novel, low-cost and online rotating rectifier fault detection method is proposed and tested. To describe these differences, the conception of ratio, residual and sum are used and corresponding functions are established. Considering the existence of interference and error of measurement, some thresholds are set to compare with values of residual, ratio and sum functions to identify these differences. Under the healthy condition, the residual is close to zero, but it will be bigger than the pre-set value when the rotating rectifier is open circuit, so it's used to identify whether the fault occurs. Through the ratio, residual and sum functions, the fault can be confirmed and fault diagnosis table is given. The simulation results verify that the proposed method is feasible and effective both in steady and transient states.