Power Control Strategy Of New Energy Electric Vehicle

As a vehicle with the most potential for development,pure electric vehicle has attracted the attention of the automotive industry around the world.The development of pure electric vehicle is limited because of its poor dynamic performance and high cost.One of the main reasons is that power batteries have the disadvantage of low power density as a single energy source.Fortunately,super-capacitors can satisfy some characteristics that battery doesn't have.Therefore,we should combine super-capacitors with high power densities and power batteries with high energy densities to create complementary advantages between them,and achieve a better battery life for pure electric vehicles while meeting their kinetic energy requirements.For this goal,we will use the composite power consisting of a power battery and a super capacitor as the onboard power supply for pure electric vehicles in this article.Based on the analysis of its characteristics,simulation modeling and parameter matching,it mainly focuses on the control strategy for the energy management of the hybrid power supply of a pure electric vehicle,and the related research work of power state of charge(SOC)prediction in energy management.The main tasks are:(1)First of all,the research background and development status of the composite power supply and the development of pure electric vehicles are summarized.It is determined that the research of composite power supply is based on the pure electric passenger vehicle.Furthermore,the structure of the composite power supply is discussed.Based on the analysis of the selection requirements and working principles of the power battery,super capacitor,and DC/DC converter,the respective characteristics of the main modules of the composite power supply are analyzed.(2)Based on the analysis of the characteristics of each module of the composite power supply,the lithium battery,super-capacitor,bi-directional DC/DC converter,power bus,and composite power supply in the composite power supply are simulated and modeled as a whole.Furthermore,the basic parameters of the whole vehicle and the performance of the pure electric vehicle are given in accordance with national standards for car manufacture,and the parameter matching of the drive motor,the power battery and the super capacitor is performed on this basis.(3)In order to meet the control target of the composite power system that the motor demand power is reasonably allocated to the super capacitor and the power battery,combined with the analysis of its operating mode,and based on the relationship between the output power of super capacitor SOC and the battery SOC.This paper proposes a fuzzy power control strategy based on power distribution and validates the simulation.The simulation results show that the fuzzy control strategy based on the power distribution of the composite power source achieves the requirements of the composite power supply energy control system and achieves the effect of “cutting peaks and filling valleys”.The advantages of the super-capacitor are optimized while the battery's charge and discharge performance is optimized to prevent the battery from being damaged by high-power charge and discharge,ensuring the normal working life of the power battery.(4)The prediction of power battery SOC is an important basis for power energy management.In order to ensure accurate real-time prediction of power battery SOC,a prediction model based on particle swarm optimization limit learning machine was proposed and verified by simulation.The simulation results show that the optimized limit learning machine has higher prediction accuracy,better stability and generalization on the basis of satisfying the prediction requirements,and is a better guarantee for the energy management control of the composite power supply.