Modeling And Control Of MWh Vanadium Redox Battery System

With the development of large-scale energy storage technology,energy storage batteries are required to have higher power and larger capacity.Vanadium redox battery(VRB)has been widely used in large-scale energy storage system because of its many advantages and broad applications.In order to coordinate energy storage system with power system,it is urgent to build a VRB model which can reflect the electrochemical characteristics and meets the requirements of power system.A model of MWh Vanadium redox battery system(MWhVRBS)is constructed,and its balancing control is realized.The main research contents are as follows:Firstly,on the basis of current research of VRB modeling,according to the basic structure and electrochemical reaction principle of VRB,a VRB model is constructed,which includes three sub-modules: electrochemical module,hydrodynamic module and circuit module.The VRB model is built to analyze the effect of vanadium ion concentration and electrolyte flow.Results show that the model can dynamically reflect the electrochemical characteristics and external output characteristics of VRB.Secondly,the MWhVRBS model is constructed,which is composed of VRB model in series.Then,a mechanism model of VRB model is given,and the quantitative relationship between parameters and MWhVRBS circuit model is deduced.The influence of initial conditions,internal resistance and capacity on dynamic characteristics of MWhVRBS is studied.Finally,by comparing the C circuit with LC oscillation circuit,a equalization scheme based on LC oscillation circuit is determined.The influence of different LC circuit parameters on the equalization performance is studied and appropriate circuit parameters are selected.The MWhVRBS is charged and discharged by the extreme value equalization control strategy.The system is balanced in a single charge-discharge cycle,which improves the effective energy utilization of MWhVRBS.The portable VRB test system is built to acquire real-time charging and discharging information of VRB online,which can provide data to verify the availability of the VRB model,and providing guidance for its engineering application.