Study On The Driving Control Strategy For Pure Electric Vehicles

With the energy crisis,environmental pollution and the greenhouse effect becoming increasingly serious,Requirements for energy conservation and emissions reduction is getting strict anymore.The development of new energy vehicles has become the inevitable trend.The vehicle drive control strategy is one of the critical technologies of the electric vehicles.The performance of the power,economic and safety of the electric vehicles are affected by the quality of the control strategy of VCU.The research of this paper is based on the project “International Science & Technology Cooperation Program of China(2014DFG70840)”.In this paper,the parameters of different parts in the powertrain system are matched.The vehicle drive control strategy was established according to different driving conditions.On the basis of which,the control strategy is verified by a vehicle simulation model.The main research work in this paper is as follows:(1)Parameter matching of the powertrain system.The main parameters of drive motor,as well as the gearbox speed ratio and batterypack,were matched according to demands of vehicle parameters plus dynamic and economic indicators.The performance of power and economic of the vehicle were verified by the simulation software ADVISOR2002.(2)According to different driving conditions,it was divided into 5 categories,which are Start Mode,Normal Drive Mode,Limp Mode,Reverse Mode and Idle Mode.And the switch logic between these five modes is set.The driving control strateges of Start Mode,Normal Drive Mode and Limp Mode are established based on the dynamic analysis of Start Mode and Normal Drive Mode.The research is especially focused on the driving torque optimal control strategy in Normal Drive Mode.A fuzzy controller is established which adopts the fuzzy algorithm with the openness of the accelerator pedal,its' change rate and the speed of the vehicle as the input variables,the increment of compensation torque as the output variable to optimize the reference torque.(3)The driving cycle model,as well as driver model,vehicle model,driving motor model,battery model and gear-box model.And then,the vehicle drive control strategy was simulated in Start Mode,Normal Drive Mode,Limp Mode and different driving cycles.The simulation results were analyzed and summarized.