Study On The Fault Diagnosis For Power Converter Of Switched Reluctance Motor

Fault diagnosis for power converter of switched reluctance motor drive is studiedin this thesis. Firstly, research status of fault diagnosis of switched reluctance motordrive is introduced, the significance of fault diagnosis for power cnverter is explained.Fault types of power converter are introduced, motor’s excitation circuit andfreewheeling circuit after open circuit fault and short circuit fault of power devices aregiven. The effects of open circuit fault and short circuit fault on motor are analyzed.This thesis takes three-phase public switching, three-phase asymmetrical half-bridge,four-phase public switching and four-phase asymmetrical half-bridge powerconverters as the research objects. Nonlinear simulation models of above systems arebuilt in matlab. Open circuit fault and short circuit fault of power devices aresimulated. Through analyzing the spectrum of phase current and bus current, themethod which can take phase current relative spectral coefficients λ as fault feature todetect the short circuit fault of power devices and the method which can take buscurrent relative spectral coefficients η as fault feature to detect the open circuit fault ofpower devices are summarized in this thesis. Finally, hardware platforms are built byusing fault simulative devices designed with relays. Experiments of short circuit faultof four kinds of power converters and open circuit fault of public switching powerconverters are done. The validity of the methods which detects open and short circuitfault of power devices are proved by the spectral analysis of phase current and buscurrent expermental results.