Study On General Layout Design And Control Strategy Of 48V Mild Hybrid Vehicle

With the rapid development of the global economy and the continuous improvement of people's living standards,the number of cars is also rising rapidly.At the same time,environmental pollution and the shortage of energy supply are becoming more and more serious,which restrict the healthy and sustainable development of automobile manufacturing industry.Developing new energy vehicles will become an important way to save energy and reduce pollution.As a transition model from traditional fuel vehicles to pure electric vehicles,48 V mild hybrid vehicles can achieve more effective energy conservation and emission reduction,and meet the requirements of the new fuel consumption and emission regulations.Moreover,the vehicle has a small momentum of change and relatively low cost increase,so it has a good market application prospect and is suitable for vigorous promotion.This thesis takes a traditional car as the prototype to design a 48 V mild hybrid power system.First of all,this thesis introduces the structural composition and can realize the main functions of 48 V mild hybrid vehicles,After comprehensive comparison and analysis of the layout configuration of 48 V mild hybrid power system,it is determined that P0 layout configuration scheme is adopted in this thesis.And through the comparison and analysis with 12 V electrical system energy saving technical scheme,Based on the latest fuel consumption regulations,the advantages of choosing 48 V power system are analyzed.Then,based on the prototype,the overall performance target of 48 V vehicle is formulated.Key components of 48 V mild hybrid system(BSG motor and 48 V power battery)is selectioned,and the parameters of the key components were designed according to performance design goals and automobile related theoretical knowledge.The main components of the 48 V vehicle(powertrain,DC-DC converter,48 V power battery and 48 V harness,etc.)were arranged and designed.And through the comparison of each arrangement scheme,the optimal arrangement scheme is finally determined.Finally,based on the analysis of the vehicle working mode,the appropriate vehicle control strategy was formulated,and the control strategy simulation model was established based on MATLAB/Simulink software and the vehicle model was established based on Cruise software.The dynamic and economic simulation analysis was carried out through the joint of the two software.The simulation results show that the 48 V mild hybrid vehicle can reduce the fuelconsumption by 10% compared with the prototype vehicle,the maximum speed is197km/h,the acceleration time of 0-100km/h is 9.75 s,the maximum climbing slope is50%,and the vehicle's power and economic performance all meet the design requirements.