Simulation Study On The Vapor Injection Heat Pump System Of Pure Electric SUV

With the economic development of human society,the problem of energy shortage has become more and more serious.Nearly cars consume three-quarters of traditional petroleum energy every year.With the rapid development of China’s economy,China’s private car market is expected to remain at the same level as the United States in 2030,and its oil consumption accounts for 20% of China’s total annual oil consumption.Traditional cars consume a lot of biochemical energy,burn gasoline and produce polluting gases,causing domestic energy crisis and environmental pollution,making domestic air protection problems increasingly serious.As new energy vehicles use renewable and highly utilized energy sources,they will make a huge contribution to energy protection and environmental improvement.Therefore,the development of new energy vehicles is an effective way to solve the above problems.Among them,pure electric vehicles are the leader of new energy vehicles.Electric vehicles have the advantages of high efficiency,zero emissions,and low noise.While having these advantages,thermal management technology has become a bottleneck restricting the development of electric vehicles.Thermal management technology not only requires thermal control of the traditional passenger compartment,but also high-voltage components such as power lithium batteries and motors that traditional vehicles do not have.Carrying out thermal control,which makes the thermal management technology of electric vehicles increasingly important.After the actual vehicle is assembled,the economic cost and time cost of the thermal management performance test of the vehicle is too high,so the simulation work of the thermal management of the electric vehicle has important value.Thermal management system simulation research mainly includes analysis of heat source generation mechanism,air conditioning system performance analysis,vehicle control strategy development,including heat generation and heat dissipation analysis of high-voltage components,heat generation and heat dissipation analysis of power lithium batteries,and air supplement enthalpy.The performance analysis of the heat pump air conditioner is also the focus of this article.First,the source of the heat load of electric vehicles is analyzed,compared with the current common heat management systems for passenger cars in the market,and a heat management scheme is proposed that uses heat pumps and motor waste heat recovery at low temperatures.Among them,the air-conditioning system is modeled based on actual physical data and working principles,and other key components are supported by experimental data to establish corresponding mathematical models.Considering the temperature of the air outlet of the passenger compartment after the thermal management system is stabilized under certain environmental conditions,the model does not consider the power consumption of low-voltage components such as external fans,blowers,and water pumps.Based on the model in this paper,a simulation platform for the airconditioning system and high-pressure component thermal management system is built;the influence of the opening degree of the high-pressure electronic expansion valve and the opening degree of the low-pressure electronic expansion valve on the heating capacity of the electric vehicle air-conditioning system is analyzed.Then,considering the corresponding motor torque and speed of the new energy vehicle for different driving states,determine the power consumption of the motor in this state according to the MAP diagram.Since the opening of the low-pressure electronic expansion valve and the high-pressure electronic expansion valve has a great influence on the performance of the supplemental air enthalpy increase heat pump system,the real-time superheat of the refrigerant at the supplementary inlet and the suction inlet is used as the target amount,and the PID algorithm is used to compare the two electronic expansion valves.Implement opening control and determine the control strategy based on the analysis of the simulation results.Finally,after the integrated simulation of the three models,the simulation results shows that the thermal management system has a good control effect on the temperature of the high-pressure parts of the model,the temperature of the power lithium battery,and the temperature of the air outlet of the passenger compartment.The air supplement heat pump is adopted.The heating method combined with the waste heat recovery of the motor is more conducive to the battery energy saving of electric vehicles in winter and extends the driving range.