Research On Torque Optimal Distribution Of Four-Wheel Motor Driven Electric Vehicle

The development of electric vehicles has become a common choice for dealing with energy security issues and air pollution problems in the transportation sector.Compared with traditional internal combustion engine vehicles and centralized distributed drive electric vehicles,distributed drive electric vehicles have become the research focus of the automotive industry because of their simple structure,independent controllable torque,fast response and compliance with automotive intelligent development.How to carry out torque distribution control to realize the energy efficiency optimization of distributed drive electric vehicles and improve the economy of the whole vehicle has become a hot issue.This paper takes four-wheel hub motor to drive electric vehicle as the research object,and designs a reasonable torque optimization distribution control strategy to improve the energy efficiency of the whole vehicle and improve the economic efficiency of the whole vehicle.In the torque distribution control with energy efficiency optimization and energy saving as the goal,according to the different driving conditions of the vehicle,it is divided into two aspects: linear driving torque optimal distribution control and steering driving torque optimal distribution control.In terms of linear driving torque distribution control,most of the current research adopts model-based control method,which requires a large number of parameters of the motor and other components.By analyzing the energy efficiency of the vehicle under straight-line driving conditions,this paper designs a torque based on the fast search algorithm.The distribution control strategy obtains the optimal distribution coefficient of the front and rear axle torques,and can distribute the demand torque to each drive wheel in real time according to different driving states,thereby improving the energy efficiency of the whole vehicle.In terms of steering torque distribution control,most of the current research focuses on stability-based torque distribution control,and less consideration is given to the energy-saving potential of steering.Through the analysis of the energy consumption characteristics of the vehicle during the steering process,this paper adopts the control strategy of “increasing the outer wheel torque and reducing the inner wheel torque” to reduce the energy consumption of the whole vehicle and exert the energy saving potential.Among them,the target centroid side declination and the actual centroid side declination are the inputvariables,and the inner and outer wheel torque adjustment amount is the output quantity.The fuzzy controller is designed to control the inner and outer wheel torque adjustment amount,so that the vehicle maintains stability during steering.At the same time play its energy saving potential.The Carsim and MATLAB/Simulink joint simulation platform that meets the requirements is built,and the simulation verification of the torque optimization distribution control strategy is completed.The simulation results show that the torque optimization distribution control strategy can effectively distribute the driving torque.Compared with the torque average distribution strategy,the linear driving torque optimization distribution control strategy improves the energy efficiency by 8% under the designed working conditions;in the ECE and 1015 cycle conditions,the energy saving reaches 7.1% and 5.2%.Compared with the torque average distribution strategy,the steering torque optimization distribution control strategy can maintain the stability of the vehicle steering and achieve energy saving of 3.27% under the selected "fish hook condition".