Disturbance Compensation For Digital Control Of Permanent Magnet Synchronous Motors

Permanent magnet synchronous motors has the characteristics of simple structure,small volume,fast response,high reliability and high efficiency.Therefore,it is widely used in servo control systems such as CNC machine tools,testing equipment,mechanical packaging and laser processing.However,in the actual control process,external and internal disturbances such as load disturbance and unmodeled dynamics will affect the permanent magnet synchronous motor,so that high-precision control cannot be achieved.Based on the power-attracting law,the double-powered attracting law and the non-switching attracting law,this paper discusses the method of suppressing the permanent magnet synchronous motor disturbance,designs the corresponding discrete controller,and completes the tracking control experiment on the permanent magnet synchronous motor experimental platform.The main contents of this paper are as follows:(1)For systems with disturbances,it is impossible to directly design the controller according to the attracting law,and a measure of the disturbance suppression is respectively implanted into the power-attracting law,the double-power attracting law and the non-switching attracting law to construct the ideal error dynamics,and based on the ideal.Error dynamic design discrete controller.In order to describe the system tracking performance and tuning controller parameters,four performance indicators of three kinds of attracting laws are given,including monotonically decreasing area,absolute attracting layer,steady-state error band and the maximum of the system tracking error entering the steady-state error band for the first time.Numerical simulations verify the accuracy of the four indicators.(2)In order to improve the control performance of the system,the disturbance of the system output is expanded into a new variable,a disturbance observer is designed to estimate the equivalent disturbance,and the observation value is used to design the disturbance suppression measure,so as to design a discrete controller with equivalent disturbance compensation.Experiments show that the disturbance observers can effectively estimate the equivalent disturbance,and the discrete controller with equivalent disturbance compensation can improve the control precision of the system.(3)For specific reference signals,such as square wave,triangle wave and S curve,different interference differences are used to form different interference suppression measures,and they are “embedded” into the power attracting law to design a discrete controller.Both numerical simulation and experiments show that the discrete controller designed in this way can complete the tracking control task of specific reference signals and has high control precision,which verifies the effectiveness of different interference difference strategies.(4)For the control system with periodic disturbance,combine the attracting law method and the repetitive control technology to design a discrete repetitive controller.Through numerical simulation,the results show that compared with the feedback controller,the repetitive controller can completely eliminate the influence of the periodic disturbance except the first period.(5)Based on the permanent magnet synchronous linear/rotary motor,ELMO servo drive and DSP2812 development board to build an experimental platform,the experimental platform is simplified to a second-order discrete model,and the specific model parameters are given.In the experimental platform,the feedback controller,the feedback controller with equivalent disturbance compensation,the repetitive controller,the repetitive controller with equivalent disturbance compensation,and the discrete controller with different disturbance differential compensation are used to verify the disturbance observers,the interference difference strategy and the repetitive controller can effectively suppress the disturbance and improve the control performance of the system.