| Today’s pure electric vehicles are developing rapidly.As an important part of pure electric vehicles,the thermal management system makes the motor,battery and other key components work in a suitable temperature range to ensure safety and service life;on the other hand,it satisfies the requirements of the passenger compartment.Heating,cooling,defrosting,defogging and other comfort requirements,in addition to reducing the energy consumption of thermal management as much as possible,making reasonable use of energy to increase driving range and ensure energy saving.The integrated thermal management technology of pure electric vehicles has become the current energy-saving application trend,and the combination of heat pump technology and the utilization of motor waste heat has become a research hotspot for improving the low-temperature driving range.This paper is based on a pure electric heat pump passenger car project of the research group,with the goal of reducing the energy consumption of the whole vehicle thermal management under high and low temperatures and increasing the driving range.From the thermal characteristics of the core components,the vehicle EV-Test test,the AMEsim integration Car model construction verification,as well as high-temperature thermal management control improvement,low-temperature thermal management configuration improvement and other aspects of research.First,a detailed functional analysis of the original vehicle thermal management system was carried out,the thermal characteristics mechanism was explained for the core components of the passenger compartment,the motor and the battery,and the corresponding AMEsim simulation module was built;related experiments were designed to obtain the battery thermal model parameters;The configuration of the vehicle heat pump system,elaborated the mechanism of each component of the heat pump,built the high temperature cooling and low temperature heating AMEsim heat pump air conditioning simulation system,and finally combined the vehicle driving module and the control module to form the vehicle thermal management simulation model.Combined with the EV-Test test data,the accuracy and reliability of the built AMEsim simulation model was verified from the aspects of high and low temperature air-conditioning pressure and temperature,motor battery circuit temperature and vehicle energy flow,and the feasibility of the utilization of motor waste heat was determined;The influence of different factors on the air-conditioning system at low temperature.In order to reduce the energy consumption of high-temperature thermal management,from the configuration aspect,the original vehicle thermal expansion valve is changed to an electronic expansion valve,and the influence of superheat is analyzed;from the control aspect,the model predictive control(MPC)optimization based on the state space equation is adopted Compressor speed control;MPC prediction model identifies the state-space equation that characterizes the heat pump refrigeration system based on the parameters of the test data.Through AMEsim and Simulink cosimulation,the MPC and PID control 3 ℃,6 ℃ and 10 ℃ evaporator outlet air temperature are analyzed.Performance,simulation results show that the compressor MPC control is more stable and energy-saving.In order to reduce the energy consumption of low-temperature thermal management,in terms of configuration,this paper constructs an integrated thermal management scheme with heat pump combined with motor waste heat;the passenger compartment heating model is built through AMEsim.The simulation results show that the motor single heat source heats the passenger compartment with a high COP value.It can reach more than 1.7,and the performance of the motor air dual heat source is slightly better than the air single heat source;compared with the original vehicle simulation model,the improved motor heat source switching scheme can save energy by 14.79%;the battery heating model is built through AMEsim,and the simulation results show that the motor is single The heat source heating performance is the best,the motor air dual heat source is the second,and the motor circulation direct heating effect is the worst.The COP value of the motor can reach more than 3 under the single heating condition,and the battery temperature rise speed is equivalent to the PTC fast charging heating speed;in addition,the passenger compartment heating The control effect of MPC is better than PID control. |
