Research On Regenerative Braking Control Strategy Of Pure Electric Vehicles

The electric vehicle regenerative braking system converts part of the kinetic energy of the car into electric energy,and recharges the battery to extend the driving distance..Regenerative braking control strategy is one of the main factors affecting the energy recovery of electric vehicle regenerative braking system.Therefore,researching the regenerative braking control strategy of electric vehicles and improving the recovery of regenerative braking energy is an effective way to improve the driving range.Regenerative braking technology makes use of the characteristic that pure electric vehicle can recover part of braking energy,improve energy utilization,and prolongs the driving distance,which plays an important role in the development of pure electric vehicles.In this paper,the electric pre-driver is taken as the research object,and the regenerative braking energy recovery control strategy is researched.Under the condition of vehicle braking stability,the front and rear braking force distribution under ECE regulations is analyzed,Based on this premise,the fuzzy control motor regeneration braking force distribution strategy is established,and the genetic algorithm is used to optimize the fuzzy control.Firstly,the characteristics and advantages and disadvantages of the structure of electric vehicle regenerative braking system are analyzed and discussed.The regenerative braking model including dynamic model,motor model,battery model and brake coupling model was established,and the factors affecting the regenerative braking feedback effect were analyzed.Secondly,based on the principle of before and after ideal braking force distribution and braking force distribution under ECE braking regulations,Combining with the analysis of the braking force of the front-drive vehicle,Based on the analysis of typical regenerative braking strategies,a reasonable braking force distribution range is formulated,Based on the analysis of existing typical regenerative braking strategies,a reasonable braking force distribution range is formulated,consider the system constraints,including battery SOC,vehicle speed,and braking intensity,to establish a three-input fuzzy controller,and a fuzzy control regenerative braking force distribution strategy is established,which is optimized by genetic algorithm.Then,the reasonable evaluation index is selected,and the control strategy simulation analysis is carried out.The proposed regenerative braking control strategy and genetic optimization control strategy are simulated under normal working conditions and driving cycle conditions.The normal operating conditions are simulated with different braking strengths different battery SOC and different speed.The cycle conditions are simulated by UDDS and NEDC conditions.The results show that the energy recovery of the optimized fuzzy controller is better than the conventional fuzzy control under different working conditions.Finally,in order to verify the effectiveness of the control strategy,the model and strategy are imported into the simulation platform by using NI hardware-in-the-loop simulation platform and NI Veristand,motohwak and other software.The experimental verification under cyclic conditions shows that the effect of the optimized control strategy is better than that of the fuzzy control strategy.