Research On Regenerative Braking Method For Electric Vehicle

With the rapid development of social economy,the problems of energy crisis and environmental pollution have become increasingly prominent.And new energy vehicle associated with it has become the focus of research and development.In urban road cycle conditions,the energy lost can account for about half of the energy required to drive the vehicle during the vehicle braking.As a key technology of electric vehicle(EV),regenerative braking technology can not only convert some of the kinetic energy into electric energy by electromagnetic braking device and store in the battery,but also reduce the energy loss and improve the economy of electric vehicle.Raising the regenerative braking rate is an important design goal of the regenerative braking system(RBS).However,various factors influence the efficiency of the regenerative braking system,such as the energy storage system,the power conversion system,the motor and the control method of RBS.This paper takes electric vehicle as the research object,and analyzes the composition and related theoretical of RBS.The main content of the research including the following aspects:(1)A new regenerative braking system structure is proposed.This RBS uses the excellent characteristics of Ultra Capacitor(UC).Moreover,the UC banks series-parallel switchover technology applied are combined with improved power converter.Thus,this RBS can realize the regenerative braking in a larger speed range to improve the regenerative efficiency;(2)The basic composition and the principle of RBS is introduced,and the vehicle dynamics equation of EV are established under the electromagnetic braking state.A new control strategy of braking force distribution is presented and has great flexibility.This control strategy can realize the independent control of the electromagnetic braking force and the mechanical braking force on the different intensity and speed of braking;(3)Based on a novel RBS and braking force distribution control strategy proposedin this paper,power supply model,power converter model,h-bridge inverter and motor model are established in the Matlab/Simulink.The feasibility of the design of the novel RBS structure and control strategy are verified by simulation.(4)A small RBS test bench is built for the further research,the correctness and effectiveness of the new RBS structure and control strategy are verified again.