Research On Regenerative Braking Control Strategy Of Pure Electric Vehicle

With the enormously improved of people's consumption level,cars become a walking tool for a growing number of people.Fuel vehicles are now causing serious environmental problems which are threaten to people's quality of life.New energy vehicles such as pure electric vehicles,because of the characteristic of less pollution or 0 pollution,are preferred by people.However,at present,the development of battery technology of pure electric vehicles has encountered bottlenecks,so the mileage of pure electric vehicles is greatly limited.Regenerative braking is converting kinetic energy into electric energy by driving motor while car braking and storing that energy to use,which greatly improves the driving mileage of pure electric vehicle.The regenerative braking control strategy studied in this paper can effectively improve the energy conversion efficiency and driving stability in braking of pure electric vehicles.This paper analyzes the recent development of regenerative braking of pure electric vehicles and the key factors affecting regenerative braking in detail,as well as the working principle of motor regenerative braking,and makes a detailed comparison and analysis of diferent driving motors and energy accumulators.On this basis,the distribution strategy of parallel and series regenerative braking force is further analyzed.Based on the simple parallel distribution strategy and the scries distribution strategy with more energy recovery,but the control structure is complex,which is not conducive to the realization of the characteristics,this paper puts out that according to the ECE braking regulations,the parallel distribution strategy is first adopted to distribute the braking force of the front and rear wheels,then fuzzy control strategy is adopted to distribute regenerative machinery braking force between the front and rear wheel.The allocation strategy not only embodies the simplicity of parallel distribution strategy,but also realizes the efficiency of energy recovery by using fuzzy control strategy.Finally,in order to improve the stability of pure electric vehicle braking on the road with low adhesion coefficient,this paper proposes a strategy of introducing slip ratio into braking force distribution,and designs a slip-ratio based synovial film controller to control the proportion of regenerative braking force.By controlling the real time slip ratio of the vehicle near the optimal slip ratio,this strategy can obtain the maximum adhesion force,thus making the vehicle have higher stability.The simulation results show that the vehicle has high braking stability under the condition of low adhesion coefficient pavement.Under typical urban conditions,the vehicle has a higher energy recovery ratio,thus taking into account the requirements of driving stability and mileage of pure electric vehicles.