Research On Disturbance Compensation Control Of Permanent Magnet Synchronous Motor Servo Syste

Permanent Magnet Synchronous Motor(PMSM)has been widely used in industry,production and life due to its excellent performance.However,PMSM is a nonlinear system with many variables and strong coupling between variables.Therefore,the parameters of PMSM are susceptible to external disturbances,and unknown dynamic disturbances such as parameter uncertainty change,which reduces the control performance of the system.In addition,the control strategy based on Proportional Integral(PI)is difficult to meet the control requirements of PMSM in some high-precision occasions.Therefore,how to overcome the influence of unknown machine interference on PMSM system and improve the control accuracy of PMSM system has very important research significance and value for industrial production and manufacturing.Focusing on the PMSM system affected by unknown dynamic disturbance,this paper discusses how to improve the control performance of PMSM by disturbance observation and compensation.The problems of anti-interference sliding mode control(AISMC)based on nonlinear disturbance estimator(NDE),fixed time integral sliding mode control(FTISMC)based on extended state observer(ESO),and approximation-free control(AFC)with prescribed performance are studied.The main research contents of this paper are as follows :(1)Aiming at the problem that the normal operation of permanent magnet synchronous motor is affected by unknown disturbance,a NDE + AISMC method is proposed.The NDE is designed by using the filter operation to construct the invariant manifold to estimate the unknown dynamics of the PMSM system.At the same time,an improved variable power exponential sliding mode reaching law is introduced to eliminate the chattering problem of the traditional sliding mode control.On this basis,the NDE is embedded in the design of the sliding mode controller to eliminate the influence of the unknown dynamics on the system.Finally,based on simulation and experiment,the integral sliding mode control(ISMC)method and PI control method based on nonlinear disturbance estimator are compared.The results show that compared with PI control method and NDO+ISMC method,NDE+AISMC has good response speed and stronger anti-interference ability,which can effectively improve the control performance of PMSM system.(2)In accordance how to improve the control performance and response speed of PMSM system,an ESO+FTISMC method is proposed.Firstly,the total disturbance of the system is observed by ESO,and the PMSM model is simplified.Then,the observed total disturbance is added to the designed controller as a feedforward compensation term to compensate the unknown disturbance.Secondly,an improved fixed-time integral sliding mode surface is designed,and a fixed-time integral sliding mode controller is designed to make the PMSM system state converge to a small enough region in a fixed time.The stability of the PMSM control system is proved according to the Lyapunov theorem.Compared with the traditional PI control and ESO-based linear sliding mode control(LSMC),the simulation and experimental results show that the proposed ESO+FTISMC method has stronger tracking performance than the PI method and ESO+LSMC.It can effectively improve the response speed and anti-disturbance ability of PMSM system.(3)Contraposing to the problem that too many control gain parameters will lead to large computational burden under the premise of disturbance compensation,a prescribed performance control is introduced,and an AFC method based on predetermined performance is proposed.The specified performance function and related error conversion mechanism are used to ensure the transient and steady-state errors of the permanent magnet synchronous motor system.In addition,the lumped disturbance of the system is estimated by the nonlinear disturbance estimator and introduced into the non-approximation control design to compensate the modeling uncertainty and unknown dynamics,so as to further improve the tracking performance and reduce the controller complexity.The stability of the closed-loop control system is analyzed according to the Lyapunov theorem.Finally,the simulation is carried out based on MATLAB,and the experiment is carried out on the PMSM semi-physical simulation platform LINKS-RT to verify the effectiveness of the method.