| With the depletion of resources and the deterioration of the environment,various new energy sources have been extensively developed and applied.Furthermore,the indepth research of microgrid and distributed generation technologies has been promoted on a global scale.However,the new energy has some problems,such as large fluctuation and unstable power supply,which will affect the safe and reliable operation of the power system after being connected to the grid.Therefore,cheap and efficient large-scale energy storage technology is the key to effectively improve the renewable energy grid connection.Especially,electrochemical energy storage has become a potential development direction of energy storage technology due to its flexibility,convenience,high efficiency and low maintenance cost and other advantages.This paper studies the battery management system(BMS)based on large capacity storage battery,explores the measures to ensure the safe and efficient operation of the battery pack and the methods to prolong the battery life,realizes the functions of real-time fault monitoring and maintenance of the battery.The main research contents and results of this paper are as follows:1.Model establishment and simulation verification for battery systems of largescale energy storage applications.Firstly,based on the classical battery equivalent circuit Thevenin model,a numerical simulation model of the battery is established by pre-fitting the variable parameters.Then,through the full charge and discharge test and HPPC test of the battery,the required test data is obtained,and the variable parameter Thevenin model is fitted and established.The identified second-order Thevenin battery model has high accuracy and the overall error is within 0.05 V.The results show that the calculation results of the simulation model established in this paper are in good agreement with the measured data,which can be used as a powerful tool for battery state estimation,which lays a foundation for the design and implementation of the subsequent battery management system.2.Based on the variable-capacity RC battery model,the state of charge(SOC)estimation of the battery is implemented using an extended Kalman filter(EKF)algorithm based on the open circuit voltage(OCV)curve of the battery.The EKF algorithm not only linearizes complex battery systems to reduce the amount of computation,but also has high robustness,which can converge to real values and maintain high accuracy under the erroneous SOC initial conditions.The SOC error range after convergence in the verification result is within 0.008.3.Design and develop an energy storage battery management system.Firstly,the detailed requirements analysis of the energy storage battery management system is carried out,and the overall design scheme of the system is given from two aspects of hardware and software.The system is mainly divided into the following nine functional modules: AFE sampling module,state estimation module,charge and discharge control module,battery protection module,data storage module,signal detection module,display and alarm module,battery equalization module and communication module.Then,the hardware design and software program of each module are designed in detail,including: The corresponding circuit structure of each functional module,the working principle of its main components,and the program flow design and implementation of each functional module.In this paper,the state estimation of battery management system is studied in detail from two aspects of model and algorithm,and it is applied to the actual battery management system,and the battery management system meeting the application requirements of energy storage battery is designed and implemented.The system has perfect functions,friendly interface and stable operation,and has important practical significance and application value. |
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