Abstract:During the fault diagnosis process of the induction motor fed with variable frequency power,the fault related characteristic components are often submerged by the strong power supply due to the frequency of variability.According to the operation model of constant acceleration and constant deceleration in the speed regulation process,a fault diagnosis method is proposed for identifying the operation mode on the basis of HilbertHuang transformation method(HHT)and timefrequency transforming with the generalized Fourier transform,and the frequency signal of power line can convert to the constant frequency signal of the new timefrequency domain.Simulation shows that the method can highlight the fault features.