Research On Control Strategy Of Three-phase Shunt Active Power Filter In Micro-grid With Complex Source And Load

With the increasingly frequent use of non-linear load and other electrical equipment in micro-grid,harmonic has become one of the common power quality problems in micro-grid.Three phase shunt active power filter(SAPF)is one of the most effective devices for harmonic compensation.The main content of this paper is to study and design the control strategy of SAPF under the complex power supply and load environment of micro-grid.Firstly,aiming at the problem of micro-grid harmonic control,this paper analyzes and summarizes the current commonly used harmonic detection and control technology.The model of micro-grid is established to analyze the harmonic of nonlinear load when it is connected and disconnected in the complex source load environment.The results show that the access of nonlinear load will produce a large number of harmonic currents,which will affect the normal operation of micro-grid.Secondly,the three-phase SAPF control strategy based on the traditional FBD(Fryze-Buchholz-Dpenbrock)method is introduced.In order to solve the problem that the traditional FBD method cannot obtain a reasonable reference current signal when the grid voltage is unbalanced,a SAPF control strategy based on the improved FBD method based on the Second-Order Generalized Integrator(SOGI)is proposed.Similarly,when the grid frequency shifts,based on the traditional SOGI method,a SAPF control strategy based on generalized second-order integrator(SOGI)and frequency-locked loop(FLL)is proposed to solve Traditional methods cannot track the voltage and frequency information of the power grid in real time,and cannot effectively compensate for the problem of harmonics.Third,QPR controller is used to track the reference current in SAPF current tracking control,and PI controller is used in SAPF DC voltage control to stabilize the DC voltage.In the parameter tuning process of PI and QPR controller,a parameter tuning method based on chaos improved cat swarm optimization(CICSO)algorithm is proposed.Compared with the optimization results of particle swarm optimization(PSO)and cat swarm optimization(CSO),the results show that CICSO algorithm can optimize the control parameters of SAPF system better,and the control effect is better.Finally,the platform of experimental data sampling device is built.Through the simulation experiment based on the measured data by using MATLAB/Simulink software,the rationality and effectiveness of the two SAPF control strategies proposed in this paper are verified.The results show that the two SAPF control strategies proposed in this paper can quickly and accurately extract the reference current signal required by SAPF harmonic compensation and output reasonable compensation current Compensation current,meet the requirements of harmonic compensation.