Research On The Matching And Control Strategy Of The Air Conditioning System Of Electric Bus

As people pay more and more attention to environment and resources, the automobile industry is gradually developing towards the direction of low emission and low carbon. Pure electric vehicles with zero pollution, low noise and low energy consumption and other advantages, has been the attention of people. Air conditioning system is an important system to maintain the indoor temperature in the car, its performance directly affect the comfort of the car. At the same time,Air conditioning system is the second largest energy consumption equipment in the car, its efficiency level will effect vehicle performance and mileage.Therefore, it is very important to put forward effective control strategy by establishing the model of automobile air conditioning.In this paper, an air conditioning system of the pure electric bus as the research object,the working environment of air conditioning in summer and the heat load in car room was calculated, R134 a was selected as the refrigerant.The independent driving scheme of air conditioning system is selected.At the same time, the structure of compressor, evaporator,condenser and expansion valve are selected. According to the heat load and refrigeration cycle,the matching calculation of four main parts of the electric air conditioning system was carried out. The key data such as the displacement of compressor and the power of heat exchanger were determined.According to the transient and nonlinear characteristics of the electric vehicle air conditioning system, a variable frequency air conditioning system using fuzzy control method is designed. The thermal load model, controller model and temperature calculation module of electric air conditioning system were established.The model of heat load in car room was established by steady state heat transfer method. The fuzzy control module is based on the change of the temperature and the change rate of the temperature.Only the speed of the compressor as the output. The temperature calculation model simulates the process of the temperature change in the car. At last, the MATLAB/Simulink was used to simulate the cooling condition of the air conditioning system in summer. The initial temperature of the air in the vehicle is 35℃, the temperature stable at 25℃ after the air conditioning was opened 2 minutes. It was met the design requirements. The simulation results show that the proposed fuzzy control strategy can effectively control the temperature of the cab.