Research On Drive Control And Energy Management Strategy For Pure Electric Vehicle

As a new energy vehicle,pure electric vehicle(PEV)has been favored by the major auto companies because of its zero-emission,low noise and low using cost,and a higher technical requirement about PEV has been put forward.As the core of PEV,vehicle control technology mainly includes drive control,energy management,regenerative braking,network management and high-voltage management,et al.Drive control and energy management strategy is the most important part of vehicle control strategy,and it calculates the target torque based on driver operation,running status of vehicle and power components,in order to ensure vehicle dynamic,economy,comfort and safety of components.This article relies on 863 projects,"Design and Technology Development for a New PEV of FAW",and in close cooperation with FAW Technology Center,to carry out research on drive control and energy management strategy for pure electric vehicle,the main contents are as follows:1.We choose a foreign pure electric vehicle to do some drum tests about its drive control strategy,to provide technical support for the independent research on drive control and energy management strategy for pure electric vehicle.Through the dum tests,we draw some important conclusions:(1)Target vehicle divides the drive mode into power mode and economy mode by manual shifting,in order to meet different driving needs.(2)The electric starting of target vehicle can make vehicle starting fast and smoothly,and reach a slow speed;Anti-slip of target vehicle allows the vehicle to stop at small slope road,and keep a low speed at large slope road;Hill-starting of target vehicle can make the feeling of hill-starting consistent with the common road.(3)The control features of accelerator pedal of target vehicle satisfy the continuity,monotonicity,stability and adaptability.Power mode focuses on increasing the torque output to meet the dynamic needs of the driver.Economy mode focuses on limiting the torque output,in order to reduce energy consumption and improve the capacity and efficiency performance of power battery.(4)Target vehicle has the intention recognition of hard acceleration under power mode,in order to simulate the increased engine torque for meeting the intensive need of the driver's dynamic when at a full throttle of conventional cars.(5)Under the reverse gear of target vehicle,with the consideration of safety,although different accelerator opening degree can lead a different dynamic,vehicle will reach a low speed in the end.(6)Owing to a sudden change of target torque during mode switching,the car had a jerk,and it make passengers feel uncomfortable.(7)The limp mode of target vehicle will limit the output torque,the purpose is to reduce the energy consumption and extend the driving range at low battery.2.Based on the drum test of target vehicle,and with some theoretical research,the drive control and energy management strategy of this article mainly contains:(1)In addition to manual shifting,mode recognition strategy could automatically determine the drive mode by vehicle speed,acceleration mean value and battery SOC based on fuzzy control,and avoid the complexity of driver operations(2)In this article,PID control and slope recognition functions can achieve the same control effect of electric starting and hill-starting with target vehicle.(3)In this article,though some theoretical calculations,we develop the relationship between load factor of torque and the accelerator opening,and further develop the control features of accelerator pedal under every drive mode.(4)Under power mode,this article develops a intent recognition function of hard acceleration based on the accelerator opening degree and its change rate.(5)Under economy mode,this article comes up with a torque compensation strategy based on the accelerator opening degree and its change rate,in order to improve the dynamic of economy mode.(6)Under reverse mode,the control strategy of this article can keep the vehicle at a lower ultimate safe speed by limiting the output torque under different accelerator opening.(7)Mode switch strategy could reduce the jerk during mode switching by limiting the rate of increase of torque.(8)Under limp mode,the control strategy of this article can adjust the torque to reduce energy consumption and avoid excessive discharge of battery and motor overload.3.This article established the vehicle model under Matlab/Simulink,and completed the offline simulation of drive control and energy management strategy.Simulation results show that the model can accurately carry out the control strategy of this article,not only meet the driver's intentions,but also ensure the vehicle dynamic,economy,comfort and safety of components.