Research On Control Strategy And Optimal Capacity Allocation Of Hybrid Energy Storage In Micro-grid

As fossil energy and environment problem become increasingly prominent,it is urgent to develop clean energy at present.Wind power and photovoltaic as the representative of the clean energy is attached more and more attention.Large-scale development of wind power,photovoltaic and the corresponding grid-connected technology has become an important subject.Micro-grid as a new type of grid structure integrated with distributed generation such as wind power and photovoltaic,storage,control system and load,make full use of the clean energy and also is a good form of developping distributed generation.Micro-grid connected to the distribution network through the point of common coupling,can realize the switch between grid-connected operation and isolated power system operation.Electric vehicles as a new means of transport,get rid of the dependence on fossil fuels and have a positive effect on improving the environment resource.Considering to realize the green travel and low emission of electric vehicles in the true sense the only access is that the electric vehicles are connected to the grid integrated with distributed generation.So the paper researches the operation and optimization of micro-grid after the electric vehicles connected to micro-grid.Firstly,this paper analyzes the working principle of the wind power generation system,photovoltaic power generation system,composite energy storage system and the electric vehicles and establishes the mathematical model.Based on this,the corresponding system model is also set up.Secondly,the operation control strategies of micro-grid and inverters in micro-grid are analyzed and theoretical calculation is made.The using occasions of this control strategies are also described.Thirdly,the paper proposes a adaptive composite energy storage control strategy to dampen the power fluctuations of wind farm.It introduces the feedback of super capacitor's state to implement the control of low-pass filter and high-pass filter's time constant and distribute the power reasonably to prolong the service life of the storage.Then the effectiveness of the proposed strategy is validated through simulation.Then,a dynamic adjustment strategy about electricity price is put forward to optimize the charging and discharging of electric vehicles in micro-grid.It encourages the owners of electric vehicles to participate in micro-grid scheduling to peak load shifting.It can be seen that the task of composite energy storage is decreased for the participation of electric vehicles.Finally,the optimization model of composite energy storage capacity is established,in order to optimize the composite energy storage capacity,it uses Empirical Mode Decomposition(EMD)to split the burden of stabilization,at last the mode is solved by the particles warm optimization algorithm.The capacity of configuration of composite energy storage in different operating conditions is also compared.