Elimination of Low-speed Vibration in Vector-controlled Permanent Magnet Synchronous Motor by Real-time Adjusted Extended Kalman Filter

The inaccuracy and delay of speed feedback cause a vibration problem when the permanent magnet synchronous motor runs at low speed. As the low-speed smoothness is a key point of many applications of the permanent magnet synchronous motor, this article solves this problem by adding a real-time adjusted extended Kalman filter to low-precision-sensor vector control. In the mathematical model, the estimated speed of the extended kalman filter is significantly impacted by the deviations of the resistance and magnetic flux rather than other parameters. Thus, under i_d = 0 vector control, a R_s-ψ_f-identifier is designed to calculate the values of the resistance and flux simultaneously with a small compensating i_d. This algorithm runs on the platform in real time. Finally, the experiment results validate that when the velocity reaches as low as 1 r/min, the proposed method eliminates the vibration problem in the low-precision-sensor permanent magnet synchronous motor.