| The car is convenient for people's travel,but the traditional fuel vehicles produces a large number of harmful gases in the process of using.Along with people pay more and more attention to environmental protection and health,electric vehicles with the advantages of zero pollution,small noise,simple structure and high energy conversion efficiency have attracted people's attention once again.But the pure electric vehicle power battery itself by storage capacity constraints,the mileage is short,which is the bottleneck of the development of electric vehicle business.Therefore,under the condition of the absence of substantial breakthroughs in battery technology,analysis of recycling process of electric vehicle braking energy,improve energy efficiency of electric vehicles,is of great significance to the development of electric vehicles.Based on the above considerations,in this dissertation,the basic composition and principle of regenerative braking system for pure electric vehicle are firstly discussed and the design requirements of regenerative braking system for electric vehicles and the factors that affect the effect of energy feedback are analyzed.Then,the braking process of pure electric vehicle is analyzed,the braking force distribution curve of the front and rear axles to ensure the safety and stability of the electric vehicle is given.Three common regenerative braking control strategies are discussed and compared,the influence of regenerative braking energy recovery is further analyzed,the braking intensity z,the speed v and state of charge(SOC)of the battery are selected as inputs,and the motor regenerative braking coefficient Kd is used as output,a three-dimensional regenerative braking fuzzy controller is designed based on the theory of fuzzy control theory.The electromechanical conversion process of energy feedback is studied,the relationship between the electromagnetic torque of the permanent magnet synchronous motor(PMSM),the torque of the braking system and speed,and state of charge of the battery are analyzed quantitatively,the dynamic model based on PMSM and the energy feedback model based on power battery are established,a regenerative braking energy feedback strategy is proposed to search for the best balance point of energy recovery under the condition of braking energy recovery and braking speed of electric vehicle.Finally,the simulation is carried out by Matlab/Simulink software under specific conditions.The data obtained from the simulation are analyzed,which can provide reference for the future research of electric vehicle energy feedback. |
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