Research On Two-times Compensation Of Speed Fluctuation Of Permanent Magnet Synchronous Motor Based On State Observer

The speed is the most intuitionistic way to display of AC servo system’s control performance in the process of driving motor.There are many reasons for the speed fluctuation.There are many reasons for the speed fluctuation in practical application.It is of great significance to study the method of speed fluctuation suppression which is suitable for various working conditions.The two-time-compensation suppression method for speed fluctuation is proposed based on the AC servo system,which is designed to suppress the velocity fluctuation of different frequency components at the same time.The specific contents are as follows:The control model of AC servo system is established.The mechanism of velocity fluctuation is analyzed from the perspective of control mode.Besides,The characteristics of two kinds of speed fluctuation caused by speed error and motor structure are analyzed.Two techniques to suppress the speed fluctuation are proposed.In order to solve the problem of high frequency fluctuation caused by the traditional speed detection error in AC servo system,a full dimension state observer feedback control model of the speed loop is constructed.And the performance index of the feedback control effect of the observer is analyzed.By simulation on the MATLAB/Simulink platform,it is proved that the speed state observer feedback control method can effectively reduce the high frequency fluctuation caused by the speed detection error.In view of the influence of the slot and pole logarithm on the magnetic field energy in the motor structure,accompanied by the periodic velocity fluctuation with the change of the rotor position,a two time compensation suppression method based on the low pass filter is proposed.Both the effect of the parameters on the sampling precision and the compensation effect are analyzed.From the angle of the current ring,the method covers shortcomings of the full dimensional state observer feedback control method in the respect of suppressing periodic low frequency fluctuation.Through simulation analysis,it is proved that the two time compensation speed fluctuation suppression method can effectively restrain the periodic low frequency fluctuation caused by cogging effect.The effectiveness and robustness of the two time compensation method based on the state observer velocity fluctuation is verified by the multi condition experiment on the servo driver platform.An effective way to improve the performance of AC servo system has been put forward.