Study On Control Strategy Of Electric Driving And Regenerative Braking For Pure Electric Vehicles

In today's energy shortage and environmental pollution,energy conservation and emission reduction has become the mainstream trend in all industries around the world,which is very significant in the automobile industry."Electrification,Intelligentization,Networking and Sharing" have become the "new four modernizations" layout for the development of today's automobile industry.Among them,new energy vehicles are the main trend of electrification,and pure electric vehicles have become the development focus of new energy vehicles because of their unique advantages of zero emissions,low noise,and no pollution.Based on the optimization design and control of the performance of the pure electric vehicle power system,this paper takes the rainbow car of Dalian University of Technology as the prototype to conduct in-depth research on the motor drive and regenerative braking control strategies of electric vehicle.And a flux-weakening vector control strategy for permanent magnet synchronous motor(PMSM)based on sliding mode variable structure and a fuzzy regenerative braking control strategy based on genetic algorithm optimization are proposed.The simulation results show that the control strategy proposed in this paper further improves the dynamic and braking performance of the vehicle,and has important theoretical and application values.The main research work includes:(1)According to the vehicle parameters and dynamic performance indexes of the rainbow car,the driving dynamics model of the electric vehicle is analyzed,and the parameters matching of the electric vehicle power system was completed to meet the vehicle's dynamic performance requirements.(2)The principle of vector control is analyzed,for the PMSM with low speed and large torque,a flux-weakening vector controller is designed based on PI and sliding model control(SMC).And the modeling and simulation of the control system are completed with MATLAB/Simulink.Considering the influence of the time-varying vehicle load on the system,a PMSM-driven electric vehicle model was built,and the simulation analysis was performed with reference to the vehicle dynamic performance index.(3)The basic theory of regenerative braking for electric vehicles is studied and the typical braking force distribution strategy is analyzed.Combining mechanical braking and regenerative braking,a fuzzy regeneration braking control strategy considering variations of battery SOC,vehicle speed,and braking intensity is proposed and an optimization model based on genetic algorithm is established.(4)Based on ADVISOR,the secondary development of the modeling and control strategy for the target electric vehicle was established,and the regenerative braking strategy model proposed in this paper was constructed.Combining ADVISOR non-GUI simulation method,the optimization of the fuzzy regenerative braking strategy is realized.Combined with typical operating conditions,the vehicle simulation,comparative analysis with the non-regenerative braking and ADVISOR braking strategies are performed.