Control Strategy Of Single-phase UPQC System Based On Improved Active Disturbance Rejection Control

China has a vast territory.From power generation to transmission,and then to power consumption,the power transmission distance is far.Due to the energy loss in the transmission process,how to ensure the supply of high-quality power to users and effectively control the pollution introduced by non-linear and impact loads has important practical significance.Relevant scholars have carried out relevant research on the unified power quality regulator(UPQC).UPQC topology consists of two parts,parallel inverter and series inverter.The main function of the series inverter is voltage compensation,so that users can obtain high-quality power;The function of parallel inverter is to improve power factor.The control problem of UPQC is essentially the control problem of the inverter.In the actual operation process of the inverter,the quality of the output waveform will be low due to the dead time,nonlinear characteristics of the switch tube,etc.,which is mainly reflected in low accuracy and high harmonics.In order to solve this problem,an improved ADRC algorithm is proposed in this paper.The specific work of this paper is as follows:1)The core idea,basic principle,basic design process and parameter tuning method of ADRC are systematically introduced.The linear state extended observer(LESO)is designed,and the influence of parameters on the performance of LESO is analyzed.Then the error of traditional linear ADRC is analyzed,and the source and solution of the error are analyzed.This paper proposes an ADRC based on error feedback,which can effectively reduce the tracking error.Simulation results show the effectiveness of the proposed algorithm.2)This paper systematically introduces the basic structure and principle of UPQC,and establishes the system equation of UPQC.The detection method of grid side voltage is introduced emphatically.The traditional low-pass filter has the characteristics of low precision and complex system.The simulation results show that the proposed detection method is effective.3)Matlab/simulink simulation models of UPQC under different controls are established,and the effects of different control algorithms(proportional integral,proportional resonance,traditional ADRC,ADRC based on differential feedforward and ADRC based on error feedback)on UPQC performance are compared.Simulation results show that the proposed control algorithm is superior in performance,and the simulation results are consistent with the theoretical analysis results.