Studies On Energy Control Strategy Of Hybrid Energy Storage Systems For Electric Vehicles

With the continuous development of science and technology,automotive technology is also constantly improving.Electric vehicle,which has obvious advantages in efficiency,noise and pollutant emission,is an important direction for the future development of the automotive industry.In the deceleration,the use of motor regenerative braking capacity,part of the mechanical energy of the car can be recycled,to extend the vehicle mileage.However,the current technical bottlenecks exist in batteries,resulting in a single power supply of electric vehicles have defects on power performance and driving mileage.The Ultra-capacitor has obvious advantages over the power,efficiency and cycle life,so that it can work with the battery to improve the performance of the power system.In this paper,the distribution method of regenerative power and the energy control strategy for hybrid electric vehicle are studied.The main work is as follows:Firstly,this paper analyzes and studies the performance characteristics of the key components in the composite power supply.According to the different characteristics of each component,the function of each component in the composite power supply is determined.The parameters of the composite power supply are matched and the layout of each component is determined.Then,the regenerative braking system of pure electric vehicle is studied.In the case of permanent magnet dc motor,theory of the regenerative braking process is analyzed.Based on the consideration of ground adhesion,a braking force distribution scheme is proposed,which decide on the maximum regenerative braking force and the ideal braking force distribution curve.And the effectiveness of the braking force distribution scheme is verified by simulation test.Finally,the energy control strategy of HESS is studied.a hierarchical control strategy based on the target voltage of Ultra-capacitor is designed.According to current speed,the target voltage of Ultra-capacitor,which satisfying the performance requirements of the electric vehicle at the next time,is determined,and the control strategy is stratified according to the target voltage of Ultra-capacitor.The particle swarm optimization algorithm is used to optimize the control strategy to minimum energy loss of HESS.The results show that the strategy can reduce the impact of high current on the power battery and prolong the service life of the battery.At the same time,the control strategy can effectively improve the energy efficiency.The simulation results are verified by the bench test.