Research On Regenerative Braking Energy Control Strategy For Electric Vehicle

In recent years,with the increasing attention to the environment,the public begin to favor clean and environment-friendly electric vehicles(EV).The motor of EV drives the vehicle and pure electric vehicles without internal combustion engine used in conventional cars utilize batteries as a power source to make the motor rotates.Electric cars with less pollution need not to be considered emissions.The motor torque driving vehicle can be obtained accurately,easy to control and response quickly.Based on these characteristics of the motor,it can better improve the antilock and traction control performance of cars.Moreover,while an EV is sliding or braking,a motor as a generator can recycle the energy which can be used repeatedly,so that it may improve the energy efficiency of vehicles,and reduce the energy consumption and further.Based on the characteristics of electric vehicles above,the EV has been gained wide attention in the world;the automobile enterprises and scientific research institutes of the various countries have made deep study for new energy vehicles.At present,subjected to the restriction of battery technology,pure electric vehicles have a problem of short running mileage.The regenerative braking energy technology of electric vehicles can save the energy,which can be utilized again,so that it may extend the driving mileage.The regenerative braking force can be provided by the motor of an EV,and the braking system of an EV is different from that of traditional internal combustion engine.The braking force supplied by the electric vehicle braking system mainly includes:the mechanical friction braking force provided by the traditional hydraulic braking system;the regenerative braking force provided by the regenerative braking system.There are differences between the two braking modes,and based on the consideration of energy recovery,it is necessary to develop a reasonable control strategy in order to achieve the coordination of the regenerative braking force and the friction force.This paper aims to ensure the braking safety,improve the comfort of the vehicle when braking,and recover the braking energy as much as possible.First of all,this paper makes an analysis of the present situation of the relative research,and expounds the source of the problem and the purpose and the significance of this research.In the next part,the braking energy recovery system of electric vehicle is summarized,taking the Permanent Magnet Brushless DC Motor as an example to introduce the process of braking energy recovery detailly,and the elements that affect the energy recovery is analyzed.Then the dynamics analysis of the electric vehicle braking process is carried out and the allocation method of front and rear wheels braking force of the traditional car is introduced.Besides,take the control strategy of the maximum regenerative braking energy recovery as an example,the improvement strategies by the simulation analysis are put forward.Later,the braking force distribution strategy of the front wheel and the rear wheel for this paper is designed,and the fuzzy control method based on the brake comfort is put forward.Finally,based on the regenerative braking control strategy of this paper,the front and back simulation models are built in the ADVISOR software.Through the analysis of the simulation results,it can be drawn that,based on the strategy of this paper,the efficiency of braking energy recovery,the braking safety and the braking comfort can be improved.Thus,it verifies the superiority of this strategy and provides reference for the improvement of electric vehicle control strategy.