Optimization Control Strategy Of An Electric Passenger Vehicle Temperature Control System

Batteries,motors and motor controllers are key components of electric vehicles.Their performance is closely related to the temperature at which they operate.Therefore,it is necessary to control their temperature efficiently and reasonably.At present,the temperature management system of pure electric passenger cars are mostly integrated,such as integrated thermal management of batteries and passenger compartments.In order to save energy and increase the mileage of the vehicle,more and more researches on the thermal management technology of electric vehicles are being carried out.Aiming at the above problems,this article relies on a pure electric passenger car project as the basis to study the temperature control of its battery,motor and passenger compartment,including the structure and control strategy of the temperature control system.Firstly,the structure of the temperature control system of the prototype was studied,and the key components of the temperature control system and the parameters needed for modeling were sorted out.Subsequently,a temperature characteristic test of the lithium-ion battery was carried out,and its temperature characteristics and thermophysical parameters were obtained for inputting model parameters.Based on GT-SUITE,a software platform suitable for system modular modeling,the entire vehicle power system was modeled,including batteries,motors,drive shafts,final drive,and tires.The temperature control system was modeled.The main circulation circuit includes the drive system cooling circuit,battery circulation circuit,heating circulation circuit and refrigeration circulation circuit;the main components include power component heat capacity model,water pump model,cooling fan model,radiator model,air conditioning system model and passenger cabin model.At the same time,the control strategy of temperature control system was modeled based on MATLAB-Simulink software.Through joint simulation,the temperature performance curves of each component of the temperature control system under vehicle driving conditions and fast charging conditions are obtained.By comparing with the temperature performance obtained from actual vehicle tests,the model is determined to be accurate and reliable.In order to further reduce the energy consumption of the vehicle temperature control system,in-depth studies of the cooling strategy of the temperature control system were conducted.Specifically,the influence of the motor pump operation mode on the cooling of the motor system and the energy saving effect are analyzed,and the continuous operation mode of the motor pump is adjusted to an intermittent operation mode to achieve a certain energy saving effect on the basis of meeting the temperature control requirements.The influence of the condensing fan and the evaporating fan on the performance of the air-conditioning system was analyzed,and the control strategy of the air-conditioning fan was optimized to save the power consumption of the airconditioning system.The effects of different vehicle speeds and different battery inlet water temperature on the battery cooling process during vehicle driving are analyzed.A temperature control system model predictive control based on genetic algorithms is used to achieve the simultaneous battery and passenger compartment.