| Switched reluctance motor(SRM) is simple and highly reliable. The drive system based on it possesses the superiorities of both DC drive and AC drive system. Power convertor is an important, as well as a fault prone part in SRM drive(SRD) system. So, it is important to carry out effective fault diagnosis and fault localization at the beginning of fault state.Power convertor one phase fault will destroy the symmetry of SRM, which is featured inherently, and as a result, there will be a relative large amplitude fundamental component in bus current. A detailed mathematic explanation based on Fourier transform on this phenomenon is presented, and vectogram is adopted in this paper to visualize the relationship between bus current and phases current fundamental component. A method to conduct fault diagnosis by measuring bus current fundamental component amplitude is explored, and a method to locate fault phase by calculating phase difference between bus current and phase current fundamental components is found in the paper as well. Simulation results validated that the two methods have reasonable accuracy and reliability at different rotation rate and different load torque conditions. Besides, the advantage of wavelet transform multiresolution time-frequency domain analysis is taken, a way to conduct fault diagnosis by drawing wavelet scalogram is investigated and a scheme to estimate fault time is highlighted. Simulation results validated that fault diagnosis method using wavelet scalogram is promising and accurate in application circumstance. Meanwhile, SRD fault diagnosis experiment platform is presented, related current datum at different fault modes and different rotation rates are acquired, and results obtained by utilizing Fourier transform and wavelet transform indicate that the two methods have excellent accuracy and application potential.This paper provides some guidances to further fault-tolerance or even position sensor-less operation condition. |
