| Under the background of our country’s "dual carbon" goal,the energy reform i s accelerated,and the proportion of new power systems with renewable energy as the main body in the entire power system is rapidly increasing.Participating in power peak regulation and peak shaving and valley filling through the microgrid energy storage system can not only effectively solve the local consumption of renewable energy and balance supply and demand,but also improve power quality and ensure power grid stability.The energy storage battery is the basis of the energy storage system.The internal charge and discharge reaction of the battery is complex,and there are problems such as inconsistent voltage,overcharge,over discharge,and over temperature.In order to improve the operating efficiency of energy storage batteries,prolong the cycle life of battery packs and battery clusters,and ensure the safe and stable operation of energy storage batteries,a battery management system that meets the needs of microgrid energy storage systems is urgently needed.In view of this,combined with the existing problems and functional requirements of the energy storage system,this thesis deeply studies the joint algorithm of the SOC and SOH of the energy storage battery,and realizes the energy storage battery management system of the three-layer control unit through software and hardware design.The specific work is as follows:(1)By summarizing and comparing common electrochemical models and equivalent circuit models,and considering factors such as model structure,model calculation difficulty,and engineering implementation,a second-order RC equivalent circuit model with simple structure,moderate calculation amount,and high precision was selected.Taking NCR18650 B lithium battery as the research object,the battery model was established in MATLAB simulation software,the rated capacity of the battery was calibrated based on the maximum available capacity experiment,the battery SOC-OCV relationship and curve were obtained based on the open circuit voltage experiment,and the model parameters were ident ified online based on the RLS method.The accuracy and feasibility of the battery model are verified by the constant current pulse discharge experiment and DST condition.(2)In order to solve the problems of slow convergence and easy divergence and degradation in particle filter algorithm,extended Kalman filter is combined on the basis of particle filter algorithm.In order to reduce the deviation and the amount of calculation,macro time and micro time are introduced,and a dual time scale extended particle filter algorithm(DTS-EKPF)is proposed to jointly estimate SOC and SOH,and the DTS-EKPF algorithm is verified by experiments and basic conditions to estimate SOC.Accuracy and feasibility with SOH.The simulation results show that the average error of the DTS-EKPF joint estimation algorithm is reduced by 51% and 37%respectively compared with the general particle filter algorithm and the extended particle filter algorithm,and the algorithm has better convergence.(3)Based on the analysis of energy s torage battery management system requirements and technical index requirements,suitable energy storage BMS architecture is proposed.The energy storage battery management system is designed and implemented from the hardware and software levels.The functi ons include data acquisition,SOC and SOH joint estimation,SPI and CAN data communication,upper computer human-computer interaction and fault alarm,etc.Finally,the system platform is built for testing and verifying the feasibility of the system.The test results show that the functions of the energy storage battery management system designed in this thesis meet the expected requirements of the system design. |
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