Research On Speed Fluctuation Suppression And Position Tracking Algorithm Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor(PMSM)is widely used in AC servo systems due to its high power factor,low heat generation and simple structure.However,there exist the flux harmonic,current detection error,dead zone effect and cogging torque in the AC speed control system of PMSM,which results in the speed fluctuation of PMSM.Besides,it is difficult to achieve precise control owing to the existence of load torque,friction torque and model uncertainty of the motion control system.This paper focuses on the methods of suppressing the steady-state speed fluctuation of PMSM and the position tracking algorithms of the PMSM biaxial motion control system.Firstly,this paper analyzes the causes of the steady-state speed fluctuation on the basis of the PMSM mathematical model,and then the study of suppressing the steady-state speed fluctuation is transformed into the research of eliminating periodic interference.In this paper,a composite controller based on internal model principle(IMP)and GPIO,and a control strategy of the internal model GPIO are designed,respectively.The composite control strategy based on IMP and GPIO connects the internal model controller and the proportional controller of the speed loop in parallel to suppress the periodic interference in the system.Meanwhile,GPIO can estimate non-periodic interference and compensates it in the controller,which makes the system have good anti-interference performance.The control strategy based on the internal model GPIO is a new observer combining IMP with GPIO,which can observe both periodic and nonperiodic interference.Simulation and experiment results have proved that both schemes have a good effect on suppressing the steady-state speed fluctuation of PMSM.In the biaxial motion control system consisting of PMSMs,the traditional three-loop cascade PI control method is unable to meet the high-performance and high-precision control requirements.In this paper,two composite controllers based on the sliding mode control(SMC)and the extended state observer(ESO)are designed for two axes,which improve the antiinterference performance and tracking accuracy of the system.In order to further improve the contour accuracy of the biaxial motion control system,the tracking errors of the two axes are transformed into the contour error and the tangential error through the coordinate transformation,and then a contouring controller based on SMC and ESO is designed in this paper.In the control strategy,an ESO-based SMC law is designed for the contour error and the tangential error,and ESO is employed to estimate the lumped disturbance to ensure the antiinterference performance of the system.Simulation results have showed that the scheme can effectively reduce the contour error of the system without losing the tracking accuracy by controlling the contour error directly.