Research On Active Disturbance Rejection Control Technology Of Shunt Active Power Filter

In recent years,as the demand for electricity continues to increase,a large number of non-linear loads have been invested,which has increased the distortion of the grid current waveform and severely reduced the power quality of the grid,which has severely affected the normal operation of the entire power system.In order to better eliminate harmonics,various filtering devices and control strategies are constantly being developed and improved.With the rapid rise of power electronic technology,active power filter(APF),as a power electronic device for dynamically controlling harmonics,overcomes the shortcomings of passive power filter(PPF)and has been widely used in power systems.This article takes the shunt active power filter(SAPF)as the research object.The main research contents are as follows:1.Taking the SAPF control system as the research content,its basic working principle is explained and its mathematical model is established.On this basis,the control methods used in the voltage outer loop and the current inner loop of SAPF are respectively described,and a double closed-loop control method in which the voltage outer loop is controlled by the controller and the current inner loop is controlled by the hysteresis loop.This control method enables SAPF to take into account both the tracking control of harmonic current and the stable control of DC side voltage,while reducing the number of controllers of the entire system and improving its control performance.2.In order to solve the difficult problem of linear active disturbance rejection controller(LADRC)parameter tuning,and improve the robustness,tracking and immunity of LADRC.This paper proposes a fuzzy linear active disturbance rejection controller(Fuzzy-LADRC)suitable for SAPF voltage outer loop.The controller consists of a fuzzy proportional controller,a linear extended state observer(LESO)and a total disturbance compensation link.The stability of the controller is analyzed by using the definition of Lyapunov stability.Finally,the Matlab/Simulink simulation platform is used to verify the SAPF controlled by Fuzzy-LADRC under different operating conditions,compare and analyze with the system under PI control.The simulation results verify the correctness and effectiveness of the controller.3.In order to improve SAPF dynamic tracking speed and anti-disturbance ability of harmonic currents,this paper proposes an improved LADRC based on the basic principles of error control.The improved LADRC introduces new errors as the basis for adjusting the total disturbance in LESO.And under the premise of system stability,the controller is applied to the voltage outer loop of SAPF for control.And use frequency domain analysis method to analyze the control performance of the improved LADRC.Finally,use the Matlab/Simulink simulation platform to verify the SAPF control performance under the improved LADRC control,compare and analyze it with the traditional LADRC.The results show that the improved LADRC is superior to the traditional LADRC,has good tracking performance and anti-disturbance ability.