Research On Capacity Allocation Optimization And Operation Of Energy Storage System For Photovoltaic Power Generation

As environmental problems such as haze and pollution become increasingly prominent,new renewable energy generation technologies such as solar photovoltaic power generation are being used more and more.However,the photovoltaic power generation is random and intermittent as the environment changes,which results in problems in the photovoltaic power generation system such as the power quality and the great impact on the power grid that affect the security and stability of power grid operation.Energy storage technology is one of the effective measures to solve such problems.At present,there are a variety of energy storage batteries that are applicable to new energy generation systems.On the basis of environmental friendliness,the configuration of the capacity of the PV hybrid energy storage system,the coordination of control strategies and grid connection control strategies were studied in this paper with the adoption of a hybrid energy storage system consisting of batteries and super capacitors.First,a mathematical model of the photovoltaic array was established,and simulation verification of the photovoltaic output characteristics was performed based on the mathematical model.The structure and algorithm of the maximum power tracking of photovoltaic cells were introduced.The effectiveness of the perturbation observation method proposed by the model verification was established on the MATLAB/SIMULINK platform.Taking full consideration of the advantages and disadvantages of each energy storage unit,a hybrid energy storage model of a battery-super capacitor was proposed,and a mathematical model and a power model of the super capacitor and battery were established.Second,in order to configure the capacity of the hybrid energy storage more rationally,a hybrid energy storage capacity optimization configuration method based on energy constraints and power constraints was proposed based on the photovoltaic power generation and load power consumption in a certain area.By adopting two optimization algorithms based on improved particle swarm optimization(weight-linearly-decreased particle swarm,crowd-search-based particle swarm),the capacity configuration was obtained,and the two optimization algorithms were compared and analyzed.Finally,by analyzing and comparing the structures of several hybrid energy storage systems,a hybrid energy storage structure in which each energy storage unit is connected to the DC bus via a relatively reliable bidirectional DC/DC converter was selected,and the constant pressure control strategy of outer voltage and inner current and hybrid energy storage coordination and control strategy were adopted.Also,the bidirectional DC/AC inverter structure was studied,and a constant power PQ control strategy suitable for the grid connection of hybrid energy storage system was adopted.On the MATLAB/SIMULINK platform,a grid-connection model of a PV-based hybrid energy storage system was established,and simulation analysis were respectively carried out for the variation of the light intensity and load during grid-connection.The optimal configuration result and the feasibility of the control strategy of the hybrid energy storage system were verified by the results.