Study On Torque Distribution Approaches Based On Energy Consumption Optimization For In-wheel Motor Drive Electric Vehicle

In recent years,due to increasingly severe environmental pollution and energy crisis,countries around the world are vigorously developing electric vehicles.Among electric vehicles,the in-wheel motor drive electric vehicle has the glaring advantages of simple and compact structure,high driving efficiency,easy control etc.,which has drawn increased attention from experts and scholars in the industry.However,the lack of research on the energy saving and torque distribution methods of in-wheel drive electric vehicles leads to unreasonable torque distribution in the vehicle and the failure to take into account the optimization of energy consumption of the vehicle.In this thesis,the four-in-wheel drive vehicle is taken as the research object,and the energy saving and torque distribution methods which can extend the vehicle driving range is studied.Firstly,a four-in-wheel motor drive electric vehicle co-simulation platform was constructed using AVL Cruise and MATLAB/Simulink.The complete vehicle model includes the in-wheel motor model,battery model,tire model and driver model,established in AVL Cruise software.The vehicle dynamics model and torque distribution models are built in MATLAB/Simulink software.Secondly,the front and rear drive torque distribution control system of the four-in-wheel motor drive electric vehicle was designed.With the comprehensive goals of optimal torque distribution and energy efficiency considering energy consumption,a front and rear wheel drive torque distribution strategy based on fuzzy logic control was proposed.The simulation results of the front and rear drive torque and the corresponding energy consumption under WLTC,NEDC and a customized IM240 driving cycle conditions were obtained respectively.Thirdly,based on the above research,the vehicle front and rear torque distribution strategy based on dynamic programming control algorithm is further proposed,and the simulation results of the front and rear drive torque and the corresponding energy consumption under WLTC driving cycle condition,NEDC driving cycle condition and customized IM240 driving cycle condition are obtained.The results show that in comparison with the torque distribution based on fuzzy logic control,the torque distribution strategy utilizing dynamic programming control algorithm can effectively reduce the energy consumption of the vehicle.The energy consumption of the vehicle was reduced by 22.68%,20.73% and 21.84% under the WLTC,NEDC and customized IM240 driving cycle conditions,respectively.Finally,an in-wheel motor drive experimental test bench was built to verify the energy consumption of the front and rear torque distribution methods of the four-in-wheel motor drive electric vehicle.The experimental results show that,compared with the drive torque distribution method based on fuzzy logic control,the drive torque distribution strategy based on dynamic programming reduces the vehicle energy consumption by 23.89%,23.12% and 23.01%respectively,under the WLTC,NEDC and customized IM240 driving cycle conditions.Through the test bench experiments,it is verified that the vehicle driving torque distribution strategy based on dynamic programming proposed in this thesis has lower energy consumption,improving the energy efficiency of the vehicle and increasing the driving range of the vehicle.