Electric A/C System Study Of Electric Vehicle

With the development of electric vehicle technology, the trend of electric vehicle industrialization becomes more and more evident. Electric vehicle should provide comfortable driving and riding environment for the passengers. So a set of energy-saving and high efficient air-conditioning system is very important for its marketing. With the appearance of electric vehicles with different styles, the research and development of their air-conditioning system must face the new problems and challenge.In the thesis, application of the electric air-conditioning system to the electric vehicle is comprehensively analyzed based on the model from State Ministry of Science and Technology "863" special issue of electric vehicle --"Electric Vehicle Flat Project".The solution of the air-conditioning system which could be selected for electric vehicle are analyzed firstly. Then, the electric compressor's drive mode and the vary-speed mode which could be used on the electric vehicle are analyzed. Subsequently the types of important parts (Compressor, Drive Motor, Evaporator, Condenser) of the electric air-condition cooling circulatory system are selected, and the mathematical model of the important parts , refrigerant and electronic expansion valve are built.Then, this paper mainly discusses the matching of the electric air-condition system on the whole electric vehicle, the control model analysis of air-condition and the motor control system of the electric air-condition system, and the test evaluation analysis of the electric air-condition to the whole vehicle.(1) For matching of the electric air-condition system on the whole electric vehicle, heat field variation of motor and control system cabin is analyzed firstly. Then, heat load model of entire car is build, and heat load is calculated. After determining the status of the calculation, the thermodynamic cycle of air-conditioning systems were calculated, the parameter values of the important components were calculated, which meet the requirements of the thermodynamic cycle.(2) The motor control module of electric air conditioning system must adopt position sensorless technology based on traditional control system of Brushless DC Motor, due to the integration of motor and compressor. Specific to this particularity, software and hardware design is discussed in this paper. Then, Evaporator Refrigerant Outlet Temperature Control scheme, Evaporator Pressure Control scheme and Cabin Temperature Control scheme are analyzed respectively for electric air conditioning's integral control. Energy saving property and applicability of these three control scheme are analyzed relatively.(3) For the test evaluation analysis of the electric air-condition to the whole vehicle, simulation test have been done for refrigeration performance evaluation. Last, the effect of electric vehicle range and the electric air-condition is analyze at the UDDS driving mode.