Research On Fault Diagnosis Method Of Switched Reluctance Motor Power Converter

Switched reluctance motor has many advantages,such as simple structure,high speed regulation performance,good fault-tolerant effect,etc.Due to the fact that switched reluctance motors often operate under harsh conditions,motor drive system failures frequently occur.Therefore,it is necessary to carry out fault diagnosis research on switched reluctance motor drive system,further improve the stability,reliability and market competitiveness of switched reluctance drive system.This paper takes the four-phase 8/6 structure switched reluctance motor as the research object,establishes the corresponding nonlinear simulation model of the switched reluctance motor system in Matlab/Simulink,designs the hardware platform and software platform for the fault diagnosis experiment of the switched reluctance motor,and analyzes the main fault types and fault characteristics of the power converter.This paper focuses on offline diagnosis and online diagnosis.In offline fault diagnosis,simulation of short circuit and open circuit faults of the main switch in the power converter is conducted.Fast Fourier transform is selected to analyze phase current and bus current,obtain spectrum diagrams under various faults,summarize the method which can take the phase current relative spectrum coefficients μ as fault characteristic to detect the short circuit fault detection and the method which can take the bus current relative spectral coefficient ν as fault characteristic to detect the open circuit fault detection.The short circuit and open circuit fault experiments of the main switch were completed,and the measured current spectrum data were analyzed.The experimental and simulation results are basically consistent,indicating the effectiveness of the offline diagnosis method.In online fault diagnosis,a fault diagnosis method based on phase current analysis is proposed.The correctness of this method is verified by completing online fault diagnosis experiments under different operating conditions.The control strategy and fault diagnosis of switched reluctance motors require accurate current signals,so it is necessary to optimize the current measurement method.By optimizing the measurement position of the current sensor,a phase current reconstruction method for a four phase asymmetric half bridge power converter is proposed.A method for diagnosing current sensor bias faults based on detecting the current deviation values at the rising edge of each opening interval is proposed.Current sensor fault simulation experiments are conducted,and the experimental results are consistent with the preset faults,indicating that the current sensor bias fault diagnosis method is effective.