Research On Robust Control Of Voltage Source Rectifier Based On Active Disturbance Rejection Technology And Switching System Theory

As an interface converter between nonlinear loads and the power grid,three-phase voltage source rectifiers have been widely used due to their advantages of low current harmonics and high power factor.In recent years,the penetration rate of distributed generation has been continuously improved.On the one hand,it has provided a beneficial supplement to the power grid and improved the security and stability of the power grid.On the other hand,it has also brought some drawbacks such as voltage flicker and harmonic pollution,which poses a new challenge to the control strategy of three-phase voltage source rectifier.Therefore,this article introduces active disturbance rejection technology and switching system theory to propose a new three-phase voltage source rectifier control scheme to cope with sudden changes in power grid voltage and mismatched control algorithm parameters,and improving the robustness of the system.Firstly,this paper studies the voltage outer loop active disturbance rejection control technology of three-phase voltage source rectifier,introduces and discusses the development status of linear active disturbance rejection controller which is widely used at present,and specifically analyzes the anti-interference ability and estimation error of linear active disturbance rejection controller.The traditional linear active disturbance rejection controllers have the advantages of simple parameter tuning and strong estimation ability of low-frequency disturbances.However,when the disturbance frequency is too high,there are also problems of large disturbance estimation error and low estimation accuracy.This article introduces an improved linear active disturbance rejection controller in the voltage loop,analyzes the active interference ability and estimation error in detail,and proves that the improved linear active disturbance rejection controller has advantages such as strong anti-interference ability,high disturbance estimation accuracy,and strong ability to suppress high-frequency noise.Furthermore,in response to the problem of poor current tracking ability of traditional feedforward decoupling control strategies in the current inner loop under sudden changes in grid voltage and mismatched control algorithm parameters,a switching control strategy based on switching system theory is introduced in the current inner loop.By establishing the dynamic model of the rectifier after the balance point is changed,and designing a switching law based on Lyapunov stability theory,and proved the stability of the proposed control strategy during subsystem switching.The physical meaning of the switching control strategy is clear,the implementation is simple,and there are no parameters to be adjusted in the control algorithm,so there is no parameter tuning process.Finally,the proposed robust control scheme of three-phase voltage source rectifier is compared with simulation and experimental research.The results show that compared with traditional schemes,the proposed control scheme has better dynamic performance,smaller current tracking error,stable control performance under sudden changes in power grid voltage and mismatched control algorithm parameters,and significantly enhanced system robustness.