The Research About The Fault Diagnosis Of Synchronous Generator Brushless Excitation System’s Rotating Rectifier

Rotating diode is an important part of brushless synchronous generator’s excitation system, because it is located in a high speed rotating rotor of the generator and without the brush, so it is unable to directly monitor the working state of the diodes, therefore solve the fault diagnosis of rotating diode is a difficult problem. Extracting the excitation current located in the stator side harmonic for analysis, and make the harmonic component as the diagnostic basis for on-line monitoring is the key of the research in recent years, but most of the research just on the theoretical study and no experimental data for the basis.This paper explains the relationship between the failure of rotating diode and excitation current by the theoretical analysis and formula derivation, and respectively using Fourier transform and wavelet packet transform to extract the feature information of the exciting current. Through comparing these two ways’s ability to extract the fault information by the analysis of the experiment and theory,FFT transform is chosen as the diagnose system’s feature extraction method.This paper designs an On-line fault diagnosis system, the hardware is mainly composed of the ST company’s STM32F4Discovery development board which is carring an STM32F407VGT6 microprocessor and an external liquid crystal display, the software mainly includes the field current collection, feature information extraction, artificial neural network diagnosis and related functional modules. The System can display the real-time fault information by LCD.This paper uses the KDE35SS3 diesel generator produced by Wuxi KIPOR limited company as experimental object, and proves the feasibility of the system through online validation experiments. The experimental results show that all the 11 kinds of state about the rotating diode can be accurately diagnosed quickly. The research of brushless synchronous generator excitation system provides the theoretical analysis and experimental data for the further study of the fault diagnosis of rotating diode.