Rotating rectifier fault detection method of wound-rotor synchronous starter-generator with three-phase exciter

This study focuses on the rotating rectifier fault detection method of the wound-rotor synchronous starter-generator (WSSG) with the three-phase exciter. Due to the difference in the topography between the traditional DC filed excitation system and the three-phase exciter, the existing method for rotating rectifier fault detection of DC filed excitation system is not effective in WSSG. To solve this problem, this study points out that the ratio of the second to fourth harmonic's amplitude and the fundamental amplitude can be used as the signature after having analysed harmonic components of the exciter rotor current which is estimated by stator flux under the healthy and fault condition. The novel method puts forward that the ratio's Euclidean distance can determine whether the rotating rectifier is faulty or not, and discriminate which phase becomes a fault. By comparing the sum of the maximum and minimum faulty phase current within one cycle with a set threshold value, the location of failure diode is confirmed. The simulation results verify the effectiveness of the proposed method.