Research on fault detection method for AC servo system using FFT algorithm

This paper explores the on-line fault detection method for AC servo system, that is, when the motor has not stopped due to the fault, the fault information is detected by using the information measured from the control system. In view of the AC servo system composed of brushless DC motor, the spectrum of DC bus current is analyzed, and the characteristics of different faults are extracted to realize the on-line fault detection of the system. The normalization method of DC bus current in FFT transform, the extraction of spectrum feature of different faults and the method of fault detection are studied. Finally, the feasibility of the method is verified by simulation results.