Research On Maximum Power Point Tracking Control Strategy Of Photovoltaic Power System

Due to environmental pollution and the lack of non-renewable energy such as coal and oil,the pursuit of low-carbon life and the development of clean energy have become the trend of today’s society.Solar energy has gradually become the main direction of clean energy development in the future.During the development of solar energy,it is founded that the variability of the environment will have a great impact on the efficiency of photovoltaic system operation.How to improve the utilization of photovoltaic modules is a key issue in photovoltaic power generation systems.This thesis focuses on improving the efficiency of photovoltaic power generation system to improve the maximum power point tracking(MPPT)control algorithm.Firstly,based on the working principle of photovoltaic cells,combined with the photovoltaic cell circuit topology and characteristics,the mathematical model and the engineering mathematical model of photovoltaic cell is established.Based on this,a simulation model of photovoltaic cells is built.The influence of light intensity and temperature on the output characteristics of photovoltaic cells was analyzed.Secondly,the research and analysis of the main circuit DC/DC converter of photovoltaic system are carried out from two aspects of converter characteristics and circuit structure.According to the characteristics of the need for boosting and variable impedance of the photovoltaic cell,Boost is selected as the main circuit of the system,and the parameters are designed.Then,two maximum power point tracking control algorithms of traditional and intelligent are analyzed,and their respective advantages and disadvantages are compared.In order to solve the phenomenon that the disturbance observation method generates oscillation near the maximum power point and the problem that the fuzzy rules with the domain of the fuzzy PID algorithm cannot be adjusted when the changes of the external environment.The fuzzy PID algorithm is combined with the variable domain theory and improved conventional fuzzy PID control strategy.Finally,the simulation models of disturbance monitoring method,fuzzy PID and variable universe fuzzy PID control strategy are built,and the simulation analysis carried out under the conditions of standard and light intensity and temperature repeated change.Simulation results show that the variable universe fuzzy PID can not only effectively reduce the oscillation problem of the traditional disturbance observation method at the maximum power point,but also make up for the deficiencies of the fuzzy rules and the scope of the domain cannot be adjusted with the changes of the external environment.And when the environmental conditions change,it can be quickly stabilized at the maximum power point,effectively improving the efficiency of the photovoltaic power generation system,with good dynamic and steady state performance.