Research On Control Strategy Of Power Conversion System Based On Improved Sparrow Search Algorithm

Sparrow search algorithm(SSA)is widely used in control optimization and other fields due to its strong optimization ability and fast convergence speed.However,this algorithm still has some shortcomings,such as being prone to falling into local optimization and low particle diversity,resulting in low optimization accuracy.Aiming at the shortcomings of SSA algorithm,this paper proposes a chaotic improved sparrow search algorithm(CISSA),which is applied to the parameter tuning of the PI controller of the energy storage bidirectional converter,and analyzes the stability and stability boundary of the system under different control parameters through modeling.The main research contents of this paper are as follows:Firstly,aiming at the problems of low optimization efficiency and easy to fall into local optimization in the later stage of iteration of sparrow search algorithm,three improvements are proposed:(1)in the initialization stage of sparrow group,piece wise linear chaotic mapping(PWLCM)with excellent orbit ergodicity and parameter insensitivity is used to improve the diversity of population,expand the search range and enhance the global search ability.(2)The renewal formula of searching for honey source of reconnaissance bee and collecting bee in artificial bee colony algorithm(ABC)is applied to SSA algorithm.(3)The improved chaos strategy is introduced to disturb the sparrow in the optimal position,and then the sparrow is selected by random roulette for Levy flight disturbance,and its position is updated again to enhance the ability of the algorithm to jump out of local search.Secondly,the chaos improved sparrow search algorithm(CISSA)is used to optimize the parameters of the single/three-phase energy storage bidirectional converter controller for islanding,grid-connected and off-grid switching,and the results are compared with particle swarm optimization algorithm(PSO),the sparrow search algorithm(SSA)and improved sparrow search algorithm(LSSA).Thirdly,the harmonic state space(HSS)modeling method based on linear time periodic(LTP)system theory is used to model the small signal of the grid connected energy storage bidirectional converter.The stability and stability boundary of the converter HSS model under different control parameters are analyzed by calculating eigenvalues.Finally,a simulation model of the energy storage bidirectional converter is built in MATLAB/Simulink,and the effectiveness of CISSA algorithm in adjusting the control parameters of the converter is verified by simulation;Using a power electronics device based on xPC mode,a three-phase energy storage bidirectional converter physical platform was built,and the accuracy of CISSA algorithm in setting control parameters was verified by experiments.The simulation waveform on MATLAB/Simulink is compared with the HSS model analysis results,and the simulation verifies the correctness of the established small signal model;Using a 30 kVA programmable power supply experimental platform,the measured voltage data are imported into the converter model to verify the correctness of the stability analysis.