Disturbance Rejection Control Of Frequency Division Based Series Resonant Injection Active Power Filter

In recent years,the new energy utilization industry is booming,which is used to deal with the large number of traditional fossil energy consumption,and thus resulting shortage of energy and problems of environmental pollution.The requirements of the grid to accept new energy constantly promote the development of the technology of power quality.Because the new energy connected the grid with power electronic devices,it will produce a certain harmonic,with the increase of new energy access capacity,the impact of access to the power grid is becoming more and more serious;In order to realize the controllability and efficiency of electric energy utilization,the new electronic equipment would be widely used in power conversion and control;In addition,the continuous increase of nonlinear load makes the harmonic and other power quality problems become more and more complex.Harmonic as an important research content of power quality problems,its suppression research plays an important role to ensure power quality,maintain network security,safeguard the normal operation of the loade,has significant and practical value in engineering.In the scheme of harmonic suppression,the active power filter(APF)has become the most potential harmonic and reactive power compensation equipment with its excellent compensation characteristics.From the practical point of view,the application technology development of active power filter in low pressure systems have been fairly mature,but in a high voltage system,because the system of high voltage,large power,the capacity of APF compensation corresponds to be large,while the range of the voltage withstand level,the dealable power range and the switching frequency of the power electronic converter,all of those are limited,high capacity increase costs.In order to realize the system harmonic compensation of high voltage system,this paper takes the series resonant injection active power filter as the research object,the main research contents are as follows:1.Frequency division detection is adopted to realize the specific harmonics detection.Based on the consideration of improving the stability of the system and reducing the capacity of APF,this paper proposes the method of frequency division detection to extract and eliminate the harmonics of the power system.In this paper,the principle of frequency division and the simulation realization are analyzed,and the important significance of the APF application in medium high voltage system is pointed out;2.According to the analysis of topological structure of the APF grid,the paper puts forward the suitable circuit topology for treating high voltage system,it analyzes the structure of APF and its significance in application in the high voltage system.According to the selected APF system,the general characteristics of the system are analyzed,and the mathematical model is established;3.In the process of analyzing the mathematical modle of the system,it is clear that there is no match between the mathematical model and the actual physical object.The generalcontroller design requires precise mathematical model,but the unmodeled information of the controlled object and the possible external disturbances which affect the system output are rarely considered.All of these require that the controller has good disturbance rejection performance,Aiming at the inaccurate model of the system,a first order linear active disturbance rejection controller is designed to realize the APF tracking control of the harmonic current,Stability performance and disturbance rejection performance of the control system are discussed;4.From the point of view of practical application,the realization of the disturbance rejection control do not wish to change the original control system structure parameters,at the same time,in order to reduce the observer bandwidth disturbance estimation,the improved observer-based controller is designed.The improved controller is designed on the basis of the original controller,and uses the information of the system to reduce the observation bandwidth.In this paper,the derivation and simulation process based on this method are given,and states that the improved method is important for the application and development of the observer.