Speed Fluctuation Suppression Of PMSM Using Active Disturbance Rejection And Feedforward Compensation Control

Permanent magnet synchronous motor(PMSM)is widely used in the field of numerical control machine tools,because of its fast response speed and high positioning accuracy.Usually,vector control method and proportional integral regulator is used to achieve stable speed control in the motor.However,when the stator resistance,permanent magnet flux and other motor parameters change and the load torque is disturbed,the anti disturbance ability of the system is obviously insufficient.It is difficult to meet the requirements of high-precision speed control.Therefore,active disturbance rejection and feedforward compensation control method are introduced to solve the speed fluctuation caused by the above reasons in the paper.The active disturbance rejection control based on shuffled frog leaping algorithm is used to compensate the current and voltage disturbance caused by the parameters variation.Then the speed fluctuation is restrained.The feedforward compensation control based on load torque observer compensates the q-axis current in real time through load torque observer,to enhance the anti load disturbance ability.The main structure of the paper is as follows:1.In this paper,the internal structure and accurate mathematical model of PMSM are studied.And the equations in different coordinate systems are derived.By analyzing a variety of motor control strategies,a more flexible _di(28)0control method is selected.Combined with the transfer function system diagram of PMSM,the influence of parameter variation and load disturbance on motor speed is analyzed.And the motor robust control system is established to suppress speed fluctuation.2.In order to solve the problem of speed fluctuation caused by parameter variation,the active disturbance rejection control based on shuffled frog leaping algorithm is studied in the paper.Firstly,the basic principle of active disturbance rejection control and the structure of traditional second-order active disturbance rejection control system are analyzed.Secondly,based on the above research,a first-order active disturbance rejection controller based on model compensation structure is designed to simplify the structure and adjustable parameters.The controller optimizes the current and voltage outputs in the current loop and voltage loop,and influence of parameter changes on speed fluctuation is also reduced.Finally,the shuffled frog leaping algorithm is introduced to further optimize the parameters.The optimal parameters are obtained by calculating the feedback signal of PMSM,which further enhances the robustness of active disturbance rejection control.3.In order to solve the problem of speed fluctuation caused by load disturbance,the feedforward control based on load torque observer is studied in the paper.Firstly,the feedforward compensation control is introduced into the motor system.The optimal gain parameters of the feedforward compensation q-axis current input are determined,through the analysis of the system transfer function.Secondly,the load torque observer based on sliding mode control is introduced.The observer improves the anti disturbance ability of the torque observer based on direct calculation method.Finally,the active disturbance rejection control and feedforward compensation are combined.And a robust control system of permanent magnet synchronous motor is designed.4.Based on the c SPACE hardware in the loop simulation system,the experimental platform of PMSM drive control is built.And the corresponding software and hardware design are completed.The dynamic and static characteristics experiments of the proposed method,as well as the robustness experiments when the parameters change and load disturbance are designed.The experimental results verify the good dynamic response and robustness of the proposed method.