Research On Maximum Power Point Tracking And Grid-connection Control Strategy Of Photovoltaic Power Generation System

The exhaustion and pollution of fossil energy is now one of the severe problems faced by mankind all over the world.Focusing on the use of new energy sources can optimize the structure of the energy system to a large extent,and can solve the pollution caused by primary energy to the environment problem.This paper takes PV battery system as the research object,mainly for MPPT control technology and inverter control technology to do related research and analysis.The specific research content of the paper is as follows:First,based on the physical characteristics of the battery,the photovoltaic effect is briefly described.By simplifying the mathematical model of the battery,the output curve is analyzed on the simulation platform,and the effect of temperature and light intensity on the battery array is briefly described.The PV array model under partial shadows is constructed,and the multi-peak characteristics of PV cells are analyzed.Then,the two-stage topological structure studied by this system is proposed,and the related circuits of the front and back stages are designed.Secondly,the maximum power point tracking control method is studied,the principle and objective of MPPT control are briefly described,Using the method of comparison,three more mature control algorithm strategies are elaborated and analyzed;the phenomenon of local peaks is proposed A particle swarm optimization control strategy in which a control model is built on a simulation platform.Compared with the common control means,the emulation results increase the tracking efficiency by about 8%,and the control method can precisely change the externalities circumstances.Tracking to the peak of the system verifies the effectiveness of the optimized control strategy.Then,research on the PV grid-connected control strategy part.By analyzing the basic topological structure of the grid-connected inverter,the time-domain mathematical model of the inverter and the control model in the s-domain are established in disaffinity coordinate systems.Model and design the parameters of the filter.Aiming at the advantages and disadvantages of common grid-connected current control methods and the scope of application,the grid-connected pre-synchronization control strategy is proposed,and the pre-synchronized grid-connected controller is designed to improve and optimize the traditional control strategy.Finally,a simulation model of the PV batter system is built on the MATLAB/Simulink platform.By analyzing the simulation waveform and the harmonic components of the grid-connected current,it shows that compared with the traditional control strategy,the improved control strategy has lower current harmonics.It is reduced by about 8.04%;in order to further verify the grid-connected effect of the method,random load variables are added to the system.By analyzing the simulation output results under load changes,the system has awell grid-connected control function.Then,the grid-connected experiment was conducted on the Modeling Tech power electronics experimental platform developed by Yuankuan Energy.The experimental waveforms show that compared with the control method before optimization,the optimized control method in this paper greatly reduces the grid-connected time harmonic The wave component again verifies the effectiveness of the control method.