Research On Braking Energy Recovery Control Strategy Of Battery Electric Vehicle

With the increasingly serious problems such as energy crisis and environmental pollution,battery electric vehicles as a new type of green pollution-free means of transportation is more and more favored by the public.Compared with the traditional fuel vehicles,battery electric vehicles have a shorter driving mileage,and the braking energy recovery technology can effectively improve the energy utilization rate,thus increase driving mileage.Brake energy recovery is a technology that converts part of the car's kinetic energy into electrical energy and stores in the battery during braking or deceleration.Based on the braking energy recovery technology of battery electric vehicles and aiming at improving the efficiency of energy recovery,the braking force distribution of the front and rear wheels in the braking process of battery electric vehicles are studied,and the control strategy based on fuzzy theory is simulated.The main research contents of this thesis include:(1)The research status of braking energy recovery technology for electric vehicles at home and abroad is introduced,the structure and working principle of the braking energy recovery system are analyzed.(2)The force analysis of the driving and braking process of battery electric vehicle is carried out,and the range of the force distribution ratio of the front and rear wheels is obtained by the ECE regulations and the ideal force distribution curve of the front and rear wheels as the constraint conditions.Three typical braking force distribution control strategies are studied,and the ideal braking force distribution control strategy is finally selected to recover the braking energy.(3)The theory of fuzzy control is studied,and a fuzzy controller which takes the SOC value,braking strength and speed as the input,the proportion of the motor participating in the braking as the output is designed.(4)The control strategy model of battery electric vehicle is built by Matlab/Simulink,and embed into ADVISOR for the secondary development.The circulating condition of American cities(CYC_UDDS)is selected for simulation,and compared with the simulation results of the braking force distribution control strategy of the software.The results show that the fuzzy control strategy studied in this thesis has a better effect in braking energy recovery efficiency,and it plays an important role in improving the mileage of battery electric vehicles.