Research On Control Strategy Of Single-phase Grid-connected Inverter

With the development of society and the consumption of traditional energy and the pollution caused by traditional energy,renewable clean energy is still the focus of social development.Because of its inexhaustible advantages,solar energy has been paid more attention to in renewable energy.However,the grid connected inverter is the most important part of the grid connected PV system,which needs to be studied in depth.This paper uses MATLAB software as a research tool,in-depth study of the characteristics of photovoltaic cells,using reasonable MPPT algorithm and grid control strategy for single-phase grid connected inverter to do a more in-depth study,Then in this paper,a detailed analysis of the control strategy,simulation model is established and simulated.The main work of this paper is as follows:(1)?The working principle and the equivalent circuit of the photovoltaic cell are studied.The mathematical model is deduced,the simulation model is built to verify the influence of the solar radiation and temperature on the output performance.(2)?The analysis method,which is using the general model of photovoltaic cells has been built to verify the P&O(Perturb & Observe)method,aiming at the two shortcomings of the P&O method,we propose a different light intensity by using fuzzy control to adjust the improved perturbation step of the P&O method is verified by simulation.(3)?The single phase full bridge inverter circuit and its output filter are analyzed,at the same time,the inverter and filter type are determined.The mathematical model of the inverter main circuit is deduced,and the model is simulated in MATLAB.(4)?In this paper,the principle of PI control,PR control and improved PR control in the grid connected control strategy is analyzed and compared.Therefore the improved PR control method is selected to simulate the characteristics of the controller.