Research On Regenerative Braking Control Strategy For Electrohydraulic Hybrid Vehicle

Under the trend of environmental protection and energy crisis,the automobile industry is also stepping up the pace of research and development of new energy vehicles.Regenerative braking technology is unique to new energy vehicles.It uses the principle of the four-quadrant operation of the motor to recover braking energy.The recovered energy can be recycled and reused to increase the driving range of the car.However,when the car starts regenerative braking and driving,the motor will generate a large inrush current,and directly charging the battery will reduce the battery's performance.In response to the above problems,this article relies on the Qingdao People's Livelyhood Science and Technology Project “Research and Development of High-Efficiency Mechanical-Electro-Hydraulic Coupler”(Project Number: 19-6-1-92-nsh)to avoid the impact of large currents on the battery.A new type of hybrid electric vehicle,namely electro-hydraulic hybrid electric vehicle,was studied.In this paper,parameter matching,regenerative braking control strategy design,system modeling and joint simulation analysis are carried out.The electric drive system serves as the main power source,and the hydraulic system performs auxiliary drive,fully combining and exerting the advantages of the electric drive system and the hydraulic drive system.This paper studies a new type of hybrid electric vehicle configuration-electro-hydraulic hybrid electric vehicle.The following researches have been conducted on the regenerative braking performance of this type of hybrid vehicle.(1)A kind of electro-hydraulic hybrid power transmission system is studied.On the basis of pure electric vehicles and hydraulic hybrid vehicles,an electro-hydraulic hybrid transmission system is proposed.The characteristics of zero-emission and pollutionfree pure electric vehicles,as well as the high energy recovery rate and high power density of hydraulic systems in hydraulic hybrid vehicles,can be well combined in electrohydraulic hybrid vehicles to take advantage of the two.(2)A regenerative braking control strategy based on the principle of maximum energy recovery is studied.On the basis of complying with the braking regulations,the braking force distribution method is analyzed,and a regenerative braking control strategy suitable for electro-hydraulic hybrid vehicles is proposed.Among them are mainly divided into two modules of mode switching and energy management.Under the condition of ensuring braking stability,recover as much braking energy as possible.(3)A control strategy model and a complete vehicle model are built.The mathematical control software Matlab/Simulink software is used to build the control strategy model,and the hydraulic software AMESim software is used to build the vehicle model.Co-simulation of the control strategy model and the vehicle model.The motor torque curve,battery SOC curve,accumulator pressure curve and swash plate opening curve are analyzed to verify the rationality and effectiveness of the model.(4)The fuzzy control method is used to optimize the control strategy.The fuzzy control method is used to optimize the control strategy.Design fuzzy controller and establish fuzzy control rules.The fuzzy controller is embedded in the control strategy model to form the fuzzy control optimization control strategy.Through joint simulation,the rationality and effectiveness of the optimized control strategy are verified.