Research On Grid-connected Control Strategy Of Photovoltaic Power Generation Based On Hybrid Energy Storage

Energy crisis and environmental crisis has greatly promoted the development of new energy sources such as wind energy and solar energy.The wind power and solar energy and other new energy system output power by the climate and weather fluctuations are relatively large,when the grid on the power quality and power system stability will have a great impact,so the photovoltaic power generation system needs a sufficient capacity of energy storage equipment In order to provide a stable quality of electricity.In the traditional distributed generation,the energy storage unit is mainly through the battery charge and discharge control to achieve energy storage and transfer,when the grid will be the impact of the power grid,resulting in fluctuations in bus voltage,while the life of the battery itself It is very unfavorable.Therefore,this paper puts forward the application of hybrid energy storage system in the grid-connected photovoltaic power generation system and the combination of photovoltaic power generation system and energy storage system to form a small micro-grid system.Firstly,the basic composition and principle characteristics of the photovoltaic power generation system are studied,and the various components of the photovoltaic power generation system are analyzed and studied.Finally,the equivalent model of the PV cell and the photovoltaic power generation are given.Output characteristics of the photovoltaic power generation system in the control of some of the key basic technology for the micro-grid and network operation to provide theoretical support.Secondly,a control method of PV maximum power point tracking(MPPT)is proposed,and the principle of battery and supercapacitor energy storage is analyzed.The two kinds of energy storage devices such as battery and super capacitor are simulated and their respective applications are obtained.The characteristics of the photovoltaic power generation system,while the use of both the advantages of complementary features,thecombination of the two after the hybrid energy storage system modeling and simulation analysis,and can be achieved battery-super capacitor fast response of the DC bus voltage balance Control method.At the same time,the PV inverter used for grid connection is studied.The inverter is controlled by constant power control method,and the correctness of the control method is verified by modeling and simulation.Finally,based on the previous research,we use Matlab / Simulink to construct a microgrid model that combines the photovoltaic power generation system and the battery-supercapacitor energy storage system,and analyzes the characteristics of the grid operation.The simulation results show that,based on the hybrid storage The feasibility of the grid-connected control strategy of micro-grid has some advantages and correctness.It is proved that the feasibility of grid-connected hybrid energy storage system in the photovoltaic power generation system can reduce the impact of instantaneous energy imbalance on the power grid.Micro-grid of the practical application of development to provide a certain theoretical reference and technical support.