Research On SWISS Rectifier Based On Linear Active Disturbance Rejection Control

In the 21st century,a large number of power electronic devices are put into use with the increase of human demand for electric energy.This has brought serious harmonic pollution to the power grid and has a serious impact on power quality.Power factor correction(PFC)is widely used.Because it can suppress harmonics and improve power factor.As a new three-phase buck PFC circuit topology newly emerged in recent years,SWISS rectifier has many advantages,such as low switching loss,low current harmonic distortion rate,and high power factor.It has high scientific research value and application prospects.In this paper,the SWISS rectifier using linear active disturbance rejection control is the research object.Its working principle and control strategy are researched.Firstly,the topology and working principle of the SWISS rectifier are analyzed in detail.According to the working modes of Swiss rectifier in different switching states,the average equivalent method is proposed to make the main circuit topology of Swiss rectifier equivalent to Buck rectifier.At the same time,the equivalent Buck rectifier is modeled by using the state space average method.Its mathematical model and corresponding transfer function are derived.Secondly,aiming at the limitation of traditional proportional integral(PI)control strategy,a double closed-loop control strategy based on Linear Active Disturbance Rejection Control(LADRC)is designed to improve the Swiss rectifier,so as to improve the dynamic performance and anti-interference ability of the rectifier output.The current inner loop adopts PI control.PI controller parameters of the current inner loop are determined by frequency domain analysis.The voltage outer loop adopts LADRC.Based on the analysis of the basic principle and structure of LADRC,combined with the mathematical model of SWISS rectifier,the second-order linear active disturbance rejection controller is designed.The control block diagram and the design method of related parameters are given.Thirdly,in order to solve the problem of high harmonic distortion rate of SWISS rectifier input current,a new type of LLR-C Ⅱ filter is proposed to replace the traditional LC filter for filtering work,its related component parameters are determined,and the good filtering characteristics of LLR-C Ⅱ filter are verified by baud diagram analysis.Finally,the simulation model of Swiss rectifier is built by using MATLAB /Simulink simulation platform.The simulations of the Swiss rectifier with PI control and LADRC are carried out.The simulation results show that the dynamic performance and anti-interference performance of the switch rectifier with LADRC strategy are significantly improved.In addition,the simulations of the Swiss rectifier with LC filter and new LLR-C Ⅱ filter are carried out.The simulation results show that the LLR-C Ⅱ filter is more effective in reducing the input current distortion.