Research On Hybrid Energy Storage Capacity Configuration Of Island-type Wind-Solar Complementary Microgrid

The island-type wind-solar complementary microgrid has become a better choice for power supply in remote areas or isolated islands because of its comprehensive energy advantages and joint complementarity.Among them,energy storage technology plays an important role,which not only promotes the effective use of renewable energy,but also ensures the safe and reliable operation of the system.However,there are many types of energy storage and high cost.If the energy storage selection and capacity allocation in the microgrid are unreasonable,it is difficult to achieve optimal results not only in the operation process,but also affect the performance and configuration benefits of the energy storage system.It is of great practical significance to study the optimal allocation of energy storage capacity.In view of the above problems,the main research contents of this paper are as follows:Firstly,the mathematical model and working characteristics of micro-power sources such as photovoltaic cells,wind turbines,batteries and supercapacitors are studied,and theoretical and mathematical calculations are prepared for the rational allocation of the capacity of the hybrid energy storage system.Then,for the photovoltaic power generation system,an improved variable step size conductance increment method is used for maximum power point tracking and is used as a micro power source;for a hybrid energy storage system connected in parallel by a bidirectional DC/DC converter,a battery can be realized.And the DC bus voltage balance control strategy of super-capacitor fast response,the photovoltaic micro-grid simulation model with hybrid energy storage system is established in MATLAB/Simulink platform,the feasibility of the control strategy is verified and the energy dynamics of the battery and supercapacitor are obtained.Aiming at the problem of optimal capacity allocation of hybrid energy storage system,an improved intelligent optimization algorithm-based particle swarm optimization algorithm is proposed to solve the problem.Considering the dynamic process of energy during the operation of the hybrid energy storage system,an energy management strategy suitable for its capacity optimization configuration is established,and the calculation process of the system operation reliability index loss of power supply probability and loss of produced power probability is analyzed in detail.Secondly,the optimal objective function with the lowest life cycle cost considering the time value of capital is established.Combined with the micro-power output constraint and the system operation reliability constraint,the capacity of the island-type wind-solar hybrid micro-grid hybrid energy storage system is reasonably configured.Through MATLAB programming,the mixed energy storage capacity ratio is obtained according to the regional conditions of the example,and the optimized configuration results of the proposed algorithm are compared with the particle swarm algorithm and the optimization results of the bacterial foraging algorithm.The results of the example analysis verify the validity of the proposed algorithm and the correctness of the model.