Design Of The Controller Of Static Var Generator Based On Disturbance Observer

In recent years,the society is developing rapidly,and the process of global industrial automation is accelerating.The diversity of electrical equipment puts forward higher requirements for the power system.Power factor is an important technical index of the power system,If it is too low,the system loss will be increased and the stability of the system voltage will be affected.For the whole power system,Adding the reactive power compensation equipment can solve the problem of low power factor caused by the inductive load and capacitive load,and improving the power factor is of great significance to the stability and safe operation of power system.As an important device of reactive power compensation,static var generator(SVG)is widely used in power system and plays an important role in improving power factor.In the SVG device,the performance of the control system has a great influence on the compensation effect.Therefore,the control system of SVG has always been an important topic in the field of power electronic control.In this paper,the influence of parameter uncertainty and external disturbance on the control system is studied.The influence of reactive power on power system is introduced in this paper firstly,and the theoretical significance and research value of reactive power compensation is explained.Then,the development of reactive power compensation device is introduced.Compared with other compensation devices,the advantages of SVG are illustrated.Then,the topology of SVG and the application of classical control strategy in SVG control system are described in detail.The SVG based on voltage source rectifier topology is studied in depth.In order to reduce the uncertainty of system parameters and the influence of external disturbance on the control effect,a direct current backstepping control method based on disturbance observer(DO)is proposed in this paper.The structure of cascading voltage outer loop and current inner loop is adopted.SVG control system can be divided into two parts,i.e.DC voltage control subsystem and reactive current control subsystem.In the controller design,the DOs are used to estimate the uncertainty of the system,and the DC voltage controller and the reactive current controller are designed based on the estimated value.In the controller design of the second order system,the backstepping method is used to complete the controller design.Finally,the stability of the control system is analyzed by Lyapunov principle.In order to verify the effectiveness of the control method,the SVG simulation system is built in MATLAB/Simulink in this paper.And the control performance of the proposed DO based backstepping control method is compared with that of the traditional PI control method.On the basis of simulation,the DSP control program is written.The hardware platform is built.