| Photovoltaics is an important application in the field of new energy.In recent years,clean energy such as solar energy has been gradually focused and promoted by countries all over the world.The key attention and promotion of countries around the world.In order to improve the efficiency of distributed photovoltaic power generation,In the design of distributed photovoltaic microgrid power generation system,MPPT(maximum power point tracking)should be considered to find a new way to maximize the output power of photovoltaic array and improve the efficiency of photovoltaic microgrid power generation system.But the algorithms currently used have certain defects,resulting in the maximum power point tracking of the photovoltaic array There is an error in the point search.At the same time,in island operation and grid-connected operation of the microgrid,different control strategies need to be adopted for different situations,and in the process of switching between the two operating modes,a reasonable switching method needs to be designed to avoid impact.In view of the above situation,this article will carry out corresponding research and apply the research results to the park microgrid control strategy designed in this article.In the research process of this paper,the distributed photovoltaic power generation is selected,and the industrial park located in a city is taken as the research object to carry out the research and design.Firstly,according to the power demand of the industrial park and the local environment to analyze the load characteristics of the park,the appropriate photovoltaic power generation system and energy storage system model are selected in the overall design of the microgrid.Secondly,in the photovoltaic microgrid power generation system,the characteristics of photovoltaic cells need to be analyzed,and the mathematical model of photovoltaic cells is established.On this basis,the output characteristics of photovoltaic cells in different environments are analyzed,which lays the foundation for the next research;In this paper,through the analysis of the current traditional algorithm,the principle of MPPT algorithm is studied,aiming at the shortcomings of the current commonly used MPPT technology,adopts the joint observation method based on conductance increment and integral adjustment method to solve the error caused by the fixed step in the traditional MPPT algorithm,so as to improve the accuracy of MPPT algorithm.Thirdly,in order to maintain the stable operation of the power grid in the actual operation,it is necessary to design the corresponding control strategies for the isolated operation of the microgrid,the grid connected operation of the microgrid and the switching between the two operation modes.The traditional PQ algorithm is used to control the grid connected operation of microgrid,which is clamped by the large grid.The stability of power grid operation is improved by adjusting voltage and frequency value;Aiming at the islanding operation of microgrid,a virtual synchronous generator(VSG)is designed to realize the control of microgrid.The output damping coefficient and inertia characteristics of inverter are controlled by simulating the characteristics of synchronous motor,which can effectively improve the stability of microgrid;For the switching of the two operation modes,the dual synchronous controller of phase and amplitude is used from island operation to grid operation,and the state following controller is used from grid operation to island operation to avoid the impact of voltage and current during switching.Finally,the simulation and experimental platform is built to simulate and analyze the designed algorithm.The results show that the control method used in this paper can effectively control the stable operation of microgrid,and has great practical value to improve the reliability of microgrid operation. |
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