Research On Active Disturbance Rejection Control Of AC Servo System

AC servo system plays an important role in the traditional industry.With the development of domestic industrialization,the independent high-precision AC servo system in China is in urgent need of development.For the High-Performance AC servo system,the problem of motor torque fluctuation has always been a research hot spot.One of the methods to suppress torque fluctuation is to suppress the current harmonic in the current loop of the control system.The research goal of this thesis is to apply the ADRC technology proposed by Chinese scholars to the current loop of AC servo system to suppress the current harmonic and the torque fluctuation of motor.The main research contents are as follows:1.The development of AC servo and active disturbance rejection control(ADRC)is introduced in detail,and the background and significance of the research is pointed out.2.The mathematical model of PMSM in three coordinate systems is deduced,and the relationship between them is established by using Clark and Park transformation.Based on the mathematical model of motor,a vector control system with speed loop and current loop is built.Then three parts of ADRC theory are analyzed and introduced in detail: Tracking Differentiator(TD),Nonlinear State Error Feedback(NSEF)and Extended State Observer(ESO),from which some important ideas of ADRC theory are introduced.Provide theoretical basis for the follow-up study.3.A first-order linear ADRC for the current loop of PMSM vector control system is designed;the stability of the designed ADRC and the whole current loop is analyzed theoretically,and the parameters are adjusted.Aiming at the performance comparison of ADRC and traditional PI controller,this thesis presents a method of simultaneous interpreting the performance of the current loop ADRC with the current loop PI controller.It can theoretically prove that the ADRC is superior to the PI controller in terms of disturbance rejection capability.Finally,the current harmonic suppression ability of the current loop ADRC is verified by simulation.4.Aiming at the performance degradation of DSOGI-FLL structure used to estimate rotor speed and position information in PMSM sensorless control system,this thesis presents an analysis method,analyzes the performance degradation law of SOGI-QSG structure in digital DSOGI-FLL in detail,and carries out simulation and experimental verification.Then,aiming at the one beat lag problem of digitalSOGI-QSG structure,this thesis presents an improved digital SOGI-QSG structure based on bilinear transformation,which eliminates the one beat lag effect in digital SOGI-QSG structure,improves the performance degradation problem in digital realization,and applies the new structure to the rotor angular velocity detection of motor,which is verified by simulation.5.The PMSM vector control system with current loop ADRC and the PMSM sensorless control system based on DSOGI-FLL structure are constructed respectively by using the theoretical content of the first four chapters,and the system simulation is carried out.The correctness of the theoretical analysis in chapter three and chapter four is verified.