Research On Energy Management Of Wind-Solar Hybrid Distributed Generation System

With the rapid development of social economy,more and more electric energy is demanded.The primary energy reserves which are used to generate electricity are limited and exhausted.The research on distributed generation using wind energy and solar energy has been paid more and more attention,and the use in grid is the trend.However,the intermittency and randomness of their outputs severely limit the proportion of their incorporation.Offering an energy storage system with a certain capacity provides a good idea and approach for solving the problem.Moreover,hybrid energy storage system comes to the top.Therefore,this thesis will study from the follovwing aspects:Firstly,a brief introduction is given to application status of distributed generation and impact on the large power grid after the combination of the distributed generation technology and the distributed power supply.Then the type and classification of energy storage technology are described.In addition,a comprehensive comparison and description are given on a variety of energy storage technical characteristics and applicable conditions.Secondly,the characteristics,models and capacity characteristics of lead-acid batteries and super-capacitors are studied and analyzed in detail.The circuit model and the mathematical model are analyzed and determined.The results show that the performances of lead-acid batteries and super-capacitors are better than those of super-capacitors.Then the structure of the hybrid energy storage system is designed and the bi-directional DC/DC power converter is studied and analyzed.Thirdly,based on the problem that the micro-grid system’s three-phase power is imbalanced,this thesis puts forward the management strategy and new scheme of the hybrid energy storage system and the energy management of the hybrid energy storage system.And then the internal structure of the adjustment device of load balancing and the internal structure of the adjustment device of load balancing are analyzed.Moreover,the control method of primary power distribution,redistribution,over charge and over discharge protection,and maximum power limit of the hybrid energy storage system is improved and innovated.Finally,the simulation model of the adjustment device of load balancing and hybrid energy storage system is established by using MATLAB/Simulink platform,and the simulation analysis is carried out.It is proved that the energy management scheme and control strategy that are proposed in this thesis are correct and effective.And the power tracking ability of the hybrid energy storage system has improved greatly.At the same time,the accumulated charge and discharge energy of the lead-acid battery is significantly reduced,which proves that the method is effective to improve the function of the hybrid energy storage system and extent the service life of the lead acid battery.