| With shortage of the traditional energy and deterioration of the environment,solar energy which is clean and renewable is paid more and more attention.Because the changes of environment will directly affect the active power of photovoltaic system and cause voltage fluctuation,therefore to realize stable operation,improve the quality of electric energy and participate in scheduling,photovoltaic system needs to use the energy storage technology.In this paper,based on research of photovoltaic system which is installed hybrid energy storage,coordinated control method of the system is analyzed and studied in detail.Firstly,the control method of operating state in photovoltaic system without energy storage was studied.After analyzing the output characteristics of photovoltaic arrays,maximum power tracking control and DC bus voltage stability control of photovoltaic system were designed.And based on the mathematical model of grid connected inverter,its control method was also designed.Then,after analyzing simulation of photovoltaic system without energy storage,hybrid energy storage system which was composed of battery and super capacitor was adopted for coordinated control against the adverse effects of photovoltaic system on the grid.In determining the connection of hybrid energy storage system,the mathematical model of DC/DC converter was established.And distributed control method and centralized control method were proposed,designed and comparatively analyzed in the simulation.Finally,centralized coordination control structure of photovoltaic system based on hybrid energy storage was established and analyzed,and its operating state was divided into grid connected smoothing power operation and grid connected dispatching operation.Then the control strategy of two operating states were designed.Through using MATLAB/Simulink to build a simulation model of photovoltaic system,the effectiveness of centralized coordination control strategy of photovoltaic system is demonstrated. |
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