| In the background of the double carbon target,accelerating the development of energy saving and emission reduction and green low-carbon transformation in various fields has become a hot issue,and promoting the transformation of transportation electrification is also an important part of achieving the goal of "carbon peaking and carbon neutrality".In recent years,countries around the world have been vigorously promoting the development of pure electric vehicles,and the increase of their ownership has also led to many problems.The high temperature of the battery,motor,electric control and cockpit will affect the service life of the battery,the range of the vehicle and the comfort of the occupants.It is important to design a suitable control strategy for the thermal management of pure electric vehicles to improve the range and comfort while ensuring the safety of the vehicle.Therefore,this paper analyzes an integrated vehicle thermal management system for a type of pure electric vehicle,designs a Nonlinear Model Predictive Control(NMPC)based on genetic algorithm to find the optimum,and analyzes the results of vehicle thermal management under different control methods,as follows:(1)In this paper,an experimental bench was built and relevant experimental tests were conducted against an integrated whole-vehicle thermal management system of a type of pure electric vehicle.A one-dimensional model of the vehicle thermal management system of a pure electric vehicle was established using AMEsim one-dimensional software,including the driver’s handling model,the battery thermal management system model,the air conditioning system model,the powertrain system model and the integrated radiator model.The integrated battery thermal management system model is experimentally verified under different ambient temperature and strategy conditions of Xi’an working conditions,and the temperature change results of the battery pack and the relative error of the model are analyzed.(2)In this paper,the powertrain thermal management system and battery thermal management system are designed according to the different temperature requirements of the three electric and cockpit.For the powertrain thermal management system,the thermal management system optimization strategy is designed based on the PID controller,and a comprehensive comparison of the motor electric control temperature and thermal management system energy consumption is conducted with the switching control.The simulation results show that the PID-based control strategy can ensure the stability of the motor electric control operating temperature and effectively reduce the thermal management system energy consumption under the NEDC and Xi’an operating conditions when the ambient temperature is30℃ compared with the switching control.(3)NMPC controller is designed for the battery thermal management system model,and MATLAB/simulink software is applied to construct NMPC controller model with AMEsim software for joint simulation.Based on this,the output speed of the pump and compressor are considered comprehensively by genetic algorithm,and a comprehensive comparison of battery temperature,cockpit temperature,control system response speed and thermal management system energy consumption is conducted with switching control and PID control.The simulation results show that compared with PID control,NMPC control has faster response speed,less temperature fluctuation,and better control effect on battery temperature and cockpit temperature.In terms of energy consumption,NMPC control can effectively reduce the energy consumption of thermal management system under NEDC conditions and Xi’an conditions compared with switching control.Compared with NMPC control,PID control can further save energy.The research content of this paper has some significance to the development of the control strategy for the thermal management system of pure electric vehicles. |
