Angle misalignment detection and its suppression algorithm in rotor system based on speed signal

In detecting the angular misalignment of the rotor system, traditional vibration method requires installing additional sensors and it's susceptible to environmental factors. On the other hand, the motor current signature analysis (MCSA) method may be affected by the fundamental frequency. This paper proposed a diagnostic method based on the permanent magnet synchronous motor (PMSM) speed signal combined with a suppression algorithm. After collecting the speed signal from the motor encoder and performing FFT analysis, the fault is detected according to the amplitude of the fault characteristic frequency 2f_r in the FFT spectrum. On the basis of diagnosing the fault, a new controller algorithm is proposed by adding the PIR controller, which can effectively suppress the periodic ripple of the speed signal to improve the stability and reliability of the long-term operation of the system. The experimental results of the motor under different speeds operating conditions verify the effectiveness of the proposed strategy.