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Research On Energy Efficient Utilization Strategy Of Hybrid Energy Storage Electric Vehicle

Posted on:2018-03-31Degree:MasterType:Thesis
Country:ChinaCandidate:S H ChenFull Text:PDF
GTID:2322330536457745Subject:Solar technology and engineering
Abstract/Summary:PDF Full Text Request
Pure electric vehicle is favored by people because of its energy saving and environmental protection.But the lithium ion batteries as energy storage devices,in the face of frequent electric vehicle fast start and stop,it is difficult to meet the demand of high power transient energy dissipation,brake braking,but also directly affects the driving range of electric vehicles.At the same time,high power and high current can easily cause the battery to generate heat,which can adversely affect the battery life and the safety of the vehicle.In the storage device,which belongs to the power type super capacitor energy storage device,has the characteristics of high power fast charge and discharge,the mixed reservoir composed of super capacitor and lithium ion battery power can solve the drawbacks of single lithium battery work,has become a hot research direction of electric vehicle.In this paper,two aspects of hybrid energy storage power allocation and regenerative braking energy recovery are proposed to improve the energy efficiency:Firstly,the research background and significance of this paper,the research status of hybrid energy storage technology and domestic and international research status are summarized.Based on the analysis of existing problems of hybrid electric vehicle energy storage control and management,this paper puts forward the main problems of this paper.Secondly,the main characteristic data of lithium ion and supercapacitor are obtained by experiment.The main topological structures of the lithium-ion and supercapacitor are analyzed,and the connection method of the hybrid energy storage equipment is compared and analyzed.Finally,The constraints of the energy storage design and the objective function.Third,in order to improve the control precision of the hybrid power system,a fuzzy control strategy based on improved parameters is designed.According to the dynamic model of hybrid energy storage power unit to establish real-time state of charge,the energy storage device in real time the maximum allowable charge and discharge power and power system requirements as input parameters and develop a more accurate implementation of fuzzy control rules,hybrid energy storage control power allocation.Set up the experimental platform of fuzzy improved control strategies are compared,the experimental results show that the parameters of improved fuzzy control system to meet the power system stability,unit time lithium battery current amplitude is decreased by 5% in average,enhance the working efficiency of super capacitor,helps to prolong the life of lithium batteries.Fourth,in order to solve the problem of regenerative braking energy recovery of electric vehicle,this paper puts forward a management strategy based on improved nonlinear model predictive control.The establishment of longitudinal dynamic model of the vehicle,the regenerative braking principle and mechanical property analysis,in the face of difficulties in the process of braking control targets of input and output,the closed-loop control system of nonlinear model prediction,rolling optimization at the same time in the part of the introduction of particle swarm optimization algorithm to solve the predictive control law,to achieve global optimization.Finally,in the simulation stage,for comparison of the data before and after the improvement of control strategy,the simulation results show that the particle swarm algorithm is helpful to improve the ability to control the nonlinear prediction model,energy recovery efficiency increased by about 10%.
Keywords/Search Tags:hybrid energy storage system, energy management, Power allocation, regenerative braking
PDF Full Text Request
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