Research On Hybrid Braking Control Strategy Of Pure Electric Vehicle With Front And Rear Dual-motor Four-wheel Drive Based On CRUISE

With its high performance,zero emission and excellent body structure,electric vehicles have become the inevitable trend of automobile development.However,due to the bottleneck of battery life of electric vehicles,they cannot match the high endurance of fuel vehicles.Therefore,various technologies are needed to extend the range of electric vehicles.Regenerative braking technology converts the braking energy of an electric vehicle into electric energy for storage,and continuously charges the battery during the driving process,indirectly improving the range.Therefore,the research on regenerative braking of electric vehicles is of great significance.In this paper,the regenerative braking control strategy is studied with the four-wheel drive-front and rear double motor-electric vehicle as the research sample.On the basis of braking safety,as much as possible to ensure the recovery of braking energy,to ensure enough braking performance and range.The research in this paper will provide a certain research direction and analytical thinking for the research on the endurance of electric vehicles.(1)Firstly,discuss the technical background and development status of electric vehicle and its regenerative braking technology,analyze the mechanism of regenerative braking system of electric vehicle,study the influence factors of regenerative braking,On this basis,design the regenerative braking system structure.(2)According to the performance parameters and performance targets of the electric vehicle,select the PMSM,lithium battery and other power system components and match the parameters.The vehicle model was built based on CRUISE software platform,and the rationality and feasibility of the model were verified through simulation.(3)Analyze several classical regenerative braking control strategies comprehensively,Based on ECE curve,I curve and fixed ratio curve,a new fuzzy control hybrid braking control strategy is proposed.The control strategy can reasonably distribute the braking force,hydraulic pressure and electrical power of front and rear four-wheel drive.Design a fuzzy controller with three inputs-double outputs,and establish the control strategy by MATLAB/Simulink.(4)Compare the three cycle condition,and the CLTC-P cycle was taken as the comparison basis,select the NEDC cycle as the comparison object.CRUISE-Simulink co-simulation is carried out by means of DLL for control strategy model and vehicle model,analyze the distribution and coordination of hydraulic brake and motor brake,compare the endurance and battery performance of regenerative braking in cycle condition.The results show that the control strategy designed in this paper can greatly improve the endurance.(5)According to the braking effect and endurance,carry out a sample vehicle test.The effectiveness of the control strategy in this paper is verified by comparing different initial velocity,different brake pedal depth,and corresponding electric mechanism power and braking time.By comparing the residual electric quantity of electric vehicles with or without regenerative braking system in the same time,the endurance of the control strategy in this paper is verified.