Research On Automatic Air Conditioning Control Mode Of Electric Vehicle

With the rapid development of industry,resources and environmental problems become more and more prominent,people’s awareness of environmental protection gradually awakened,the automotive industry gradually toward the direction of green development,with its advantages of low-carbon and low-emission,electric vehicles are very popular and become a national strategy.However,the battery is the main source of power of electric vehicles,in order not to affect its Dynamic Property and mileage,the system should maintain a high energy efficiency.As a essential accessories of vehicle with large energy consumption,air-conditioning system should also have a high energy efficiency.In recent years,many researches have been carried out on different types of air-conditioning systems at home and abroad.There are many studies on the performance of components,but few studies on the control mode.With the development of automation and intelligence,the research of control mode becomes the new growth point.In this paper,through the test and simulation research of electric vehicle automatic air conditioning system control mode,we persue a strategy which can save energy and meet the cooling demands.The content of this paper is divided into four parts as follows:1.As to study the structures of air-conditioner of the experiment vehicle and mechanic of the control system involved,the working principle of Refrigeration,automatic air conditioning control system and thermal calculation were introduced,laying a foundation for the following study.2.Come so far,there is no standard for the performance verification of the electric vehicle air conditioning system,the relevant existing standards of the traditional vehicle are revised to formulate a test plan which is in accordance with the pure electric vehicle air conditioning system.The temperature distribution and change of the passengers in the cabin,air outlet was monitored,as well as the even temperature of air in cabin,in cooling,heating,defrosting and demisting performance tests.The experiment result was analyzed and three advices,that the environment must be taken into account when the cooling model is activated in summer,a combination with CFD simulation about the performance of air in cabin and road or environment test is reasonable for the system control strategy making and the defrosting and demisting mode should be controlled with a high precision individually.A patent has been claimed as the further research on defrosting and demisting mode was carried.3.Based on the analysis of the theory of automatic air conditioning control system and the calculation principle of indoor heat balance,the vehicle heat load model,air conditioning system model,indoor temperature calculation model,indoor humidity calculation model and control system model were established with the help of MATLAB / Simulink,Stateflow and Fuzzy tools.Then a research about the effects of the switch between the internal and external circulation mode,the speed of vehicle,the initial temperature of air in cabin and the varying installation of the fuzzy controllers on the temperature of air in cabin was carried out.The simulation showed that the forced ventilation carried a negative impact on the temperature change,which was expected with incline trend.It is significant when the vehicle speed decreases.So an additional research on the switch of the vehicle skylight is reasonable.The vehicle speed mainly effects the flow fluid,thus it hardly contributes to the cooling performance in inner circulation mode.The initial temperature becomes higher,the cooling performance gets worse,and when the regulation range of fuzzy controller extended,the performance was improved.In the paper,evaporating temperature of refrigerant and the temperature of the air flowing through the evaporator were controlled by proportion feedback of compressor speed and blower speed,leading to a decrease of amplitude of endless shock ring and smaller steady state error.4.In the end,the research of the paper was summarized and a method of air conditioning control mode researched by environmental wind tunnel and road test combined with CFD simulation was proposed,and the test results will be used to train the neural network to improve the control accuracy and intelligence.