Research On Repetitive Control Of Induction Motor Based On Luenberger Disturbance Observer

With the advent of industrial 4.0,the rapid development of high-performance AC speed regulation system in the fields of national defense,space,industrial robots and agricultural production has become the common concern in all fields.As the main control object of AC speed regulation system,induction motor has the characteristics of non-linearity,strong coupling,multi-variable and large disturbance.In order to further improve the control performance of induction motor,researchers have developed various control technologies of induction motors,among which Repetitive Control(RC)can suppress periodic disturbances such as current harmonics and torque ripple,at the same time it has the advantages of small amount of calculation and simple implementation process,so repetitive control has been favored by researchers.However,due to the time-varying disturbance caused by uncertain non-linear factors such as parameter variation and the load disturbance during the operation of induction motor,and the inherent delay link of repetitive control,the performance of the current loop control is degraded.To solve the above problems,the repetitive control method of induction motor based on Luenberger Disturbance Observer(LDO)is studied in this paper.Firstly,the basic vector control system is established according to the mathematical model of induction motor and the transformation relationship in different coordinate systems.Secondly,periodic disturbances such as current harmonics and torque ripple during the operation of vector control system degrade the performance of the control system.Therefore,repetitive control is introduced to suppress such periodic disturbances,and the basic principle and design method of repetitive control are introduced in detail.At the same time,the slow dynamic response of repetitive control and the existence of uncertainties such as parameter variation will affect the performance of current loop control.Therefore,based on the repetitive control system of induction motor,the luenberger disturbance observer is introduced to compensate the current loop.Firstly,the current loop equation is redesigned according to the mathematical model of induction motor and the estimated disturbance.On this basis,the luenberger disturbance observer is designed.Secondly,the stability of the ob server is analyzed by using Julie criterion,and the selection criterion of the observer gain is given.Finally,the method of current harmonic and torque ripple suppression based on vector control of induction motor and the method of repetitive control based on luenberger disturbance observer are simulated and verified by using MATLAB/Simulink.The two schemes are tested on the experimental platform of vector control system of induction motor.The simulation and experimental results show that the vector control based on repetitive control has a good suppression effect on current harmonics and torque ripple.At the same time,the dynamic response speed of the repetitive control system is improved and the robustness of the control system to parameter changes is improved by adding the luenberger disturbance ob server.