Energy Storage System And Its Energy Management Strategy Verification For Electric Vehicle Applications

Pure electric vehicle energy storage systems need to meet the requirements of high power density and high energy density at the same time,but at the present stage,a single energy storage unit is often difficult to have both features.It is an effective way to solve the above problems by reasonably matching high energy density lithium batteries with high power density super capacitors to form a composite energy storage system.The thesis takes the BMW I3 pure electric vehicle as the target model,and designs a lithium battery / supercapacitor composite energy storage system;at the same time,it formulates a rule-based energy management strategy that comprehensively considers the external working condition requirements,the charge of the lithium battery and the supercapacitor Power state,automatic planning work mode,give full play to the advantages of each energy storage unit,and can automatically start the protection mode under extreme conditions;with the help of Matlab / Simulink software modeling and simulation,establish simulation models and control strategy models of each key component Carry out software simulation verification in an ideal environment,and based on the idea of rapid control prototyping,design and build a rapid control verification platform for the energy management strategy of the composite energy storage system with dSPACE as the control center,together with external electronic load equipment that can edit power parameters,complete The semi-physical experiment verification of energy management strategy.The main contents include:According to the current status of the development of electric vehicles,the performance characteristics of each key component are analyzed,combined with the research objectives of this article,a reasonable component mix and system structure are selected;three standard test conditions are selected,and supercapacitors are selected for the test conditions Intervene in the working power,and without changing the dynamic parameters of the research vehicle,match the parameters of the selected key components to carry out the next strategy formulation and verification research.According to the current typical working conditions of electric vehicles,it is subdivided into multiple working modes.In order to cope with the different working modes of electric vehicles,combined with the energy state of the energy storage system itself,multiple logical thresholds are selected to formulate a rule-based composite Energy management strategies for energy systems.Build a compound energy storage system verification model in Matlab / Simulink,and verify the strategy under ideal environment;in order to solve the over-idealization of the working environment in the simulation,based on the idea of rapid control prototype,using dSPACE as the control center,build semi-physical Simulation verification platform to verify the control strategy in kind.Both simulation and experimental results show that the lithium battery / supercapacitor composite energy storage system of electric vehicles,together with a reasonable energy management strategy,can give full play to the energy characteristics of lithium batteries and the power characteristics of supercapacitors,and better meet the needs of modern pure electric vehicles.The requirements of cruising range and power performance can save energy at the same time.According to the analysis of cycle life,the compound energy storage system can be reasonably matched with the energy management strategy to extend the service life of the energy storage system to a certain extent.