Research On The Control Strategy For Driving Torque Of Pure Electric Vehicle

With the increasingly serious environmental pollution and energy crisis,pure electric vehicles have become more and more popular because of their advantages of zero pollution,low noise,energy saving and environmental protection.It has become an inevitable trend of the automobile industry to develop pure electric vehicles.The control technology of pure electric vehicle is one of the key technologies of its development.The performance of the control system has a decisive influence on the vehicle performance.As the core design content of vehicle control system,the drive torque control strategy plays a key role in vehicle safety and economy.Based on the control objectives of pure electric vehicle under different driving conditions,the driving torque control strategy of each mode is studied.The main contents are as follows:(1)The existing pure electric vehicle structure and the performance requirement of the pure electric vehicle are analyzed.The parameters selection and design of the key components of the vehicle power system are made according to the basic parameters of the target car and the design requirements,including the driving motor,the design of the power battery parameters and the determination of the type of transmission and the speed ratio of the vehicle.(2)Aiming at the development target of the vehicle control system for the pure electric vehicle under different driving conditions,the driving torque control strategy of starting mode,driving mode(dynamic mode and economic mode),backward gear mode and limp mode is formulated,and torque constraint module is set up for the motor faults.(3)Based on fuzzy control,torque is optimized on the basis of driving mode torque control strategy.In the dynamic model,the output torque is optimized by using the speed,the speed of the accelerator pedal and the change rate as the fuzzy input,and the rapid acceleration intention recognition is added,which makes the vehicle dynamic performance more prominent,the driver’s driving intention is more sensitive,and the state of charge of power battery is considered in the economic mode torque optimization.While ensuring the economic performance of the vehicle,it improves the dynamic performance of the vehicle when the driver has accelerated demand,which will enhance the practicability of the mode to a certain extent.(4)The whole vehicle simulation model is built in the Matlab/Simulink software environment,including vehicle dynamics model,motor model,battery model,and driving torque control strategy model.The feasibility of driving torque control strategy for pure electric vehicles in starting,driving,reverse and limping is simulated and verified.The simulation results show that the proposed torque control strategy can meet the control target of the pure electric vehicle under different driving conditions,while ensuring the economy of the vehicle,it takes the dynamic performance of the vehicle into account at the time of acceleration and improves the practicability of the driving modes.