| With the development of society,environmental problems and energy crisis have become increasingly prominent,which has aroused widespread concern.In order to solve these problems and realize the goal of "double carbon" as soon as possible,many scholars and experts are committed to the utilization and development of wind energy,solar energy and other clean energy,and the solar energy storage micro-grid system is thus born.The microgrid is mainly composed of wind power generation,photovoltaic power generation,energy storage and control.Due to the complexity of the system,problems such as frequency and voltage fluctuations may occur in the control process.In view of these problems,this paper mainly studies the off-grid switching of the windpower storage microgrid system,and its contents are as follows:Firstly,the overall structure of the wind-power storage microgrid is analyzed,and the characteristics of the microgrid are explored.According to the basic theory of the wind power system,the mathematical model is built,and the maximum power tracking technology of the wind power system is introduced.Then the simulation in MATLAB/Simulink verifies the validity of the model.Secondly,the photovoltaic power generation system is studied and analyzed.According to the basic theory of photovoltaic power generation,its mathematical model is constructed,the maximum power tracking technology of photovoltaic power generation system is introduced,and the improved method of disturbance observation method is proposed and simulated to verify its feasibility.The maximum power not be tracked under local illumination shadows by a composite algorithm combining the perturbation observation method and the improved particle swarm optimization algorithm.The effectiveness of the algorithm is verified by experimental simulation.Then,the working principle of lead-acid battery energy storage system is introduced,and the charge and discharge control method of the energy storage system is introduced.The voltage and current double closed-loop control strategy is adopted,and the circuit protection device is added to prevent the over rush and over discharge of the battery.The effectiveness of the control method is verified by model simulation.Finally,the basic control strategy of the microgrid system and several common control strategies of inverters in the system are studied,and the grid-connected PQ control,off-grid V/f control and Droop control are analyzed.The mathematical model is constructed and the experimental simulation is carried out to verify its effectiveness,which lays a theoretical foundation for the study of master-slave integrated control of the wind-solar storage microgrid.Then,the reasons for the current,frequency and other amplitude changes during the switching of the microgrid are analyzed,and the improvement methods are proposed.The modeling and simulation analysis was carried out in MATLAB/Simulink to verify the new master-slave integrated control strategy and realize the smooth switching of microgrid and off-grid. |
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