Research On Heating Performance And Control Strategy Of Electric Vehicle Heat Pump Air Conditioning System

With the increasingly severe environmental pollution and energy crisis,pure electric vehicles have become the main direction of the development of modern automobile industry.Heat pump air conditioning has the advantages of high efficiency and energy saving.The application of heat pump air conditioning technology in pure electric vehicles can reduce the energy consumption of air conditioning system,which is of great significance to improve the range of electric vehicles.In view of the low heating speed and low efficiency of the pure electric vehicle heat pump air conditioning system in the low temperature condition,this thesis proposes a compound heat source heat pump air conditioning system,and studies the heating performance of the system.In addition,in view of the complex operating conditions of the electric vehicle heat pump air conditioning system,which has the characteristics of nonlinearity and hysteresis,this thesis studies the control strategy of the heat pump air conditioning system.The main work of this thesis includes:1.Research on the model of heat pump air conditioning systemThis thesis studies the theory of heat pump air conditioning system,and briefly introduces the working principle of heat pump air conditioning system.The simulation model of heat pump air conditioning system is established in AMESim environment,and the experimental data collected from the heating mode of a certain model of heat pump air conditioning system under various working conditions are used to complete the verification of the simulation model of heat pump air conditioning system.2.Performance analysis of compound heat source heat pump air conditioning systemBased on the simulation model,this thesis compares the heating performance of the hybrid heat pump air conditioning system with that of the single heat pump air conditioning system under various working conditions.The simulation results show that the compound heat source heat pump air conditioning system can effectively recover the residual heat of the driving motor,reduce the heat exchange load of the evaporator,and improve the heating performance of the heat pump air conditioning system.3.Research on control strategy based on Fuzzy PID and BP-PIDFacing the nonlinear,time-variable and hysteretic system of heat pump air conditioning system,the PID control strategy which is widely used in air conditioning system is difficult to adjust parameters in real time,resulting in system overshoot and low accuracy.Fuzzy PID controller not only has the adaptability of fuzzy control,but also retains the accuracy of PID control.BP-PID controller uses the self-learning ability of BP neural network to adjust PID parameters in real time to achieve good control effect.Through AMESim and matlanb joint simulation,the results show that the Fuzzy PID controller and BP-PID controller have no obvious overshoot in the process of temperature regulation under various working conditions,and the control accuracy is high.4.Research on control strategy based on sliding mode controllerIn view of the PID control strategy widely used in the heat pump air conditioning system at present,the sliding mode control strategy is proposed for the problems of low control accuracy and poor anti-interference under complex working conditions.Through AMESim and matlanb joint simulation,the results show that compared with PID controller,the sliding mode controller has no obvious fluctuation in the process of temperature regulation under complex working conditions,faster response speed,higher control accuracy,and strong anti-interference under the interference of vehicle speed and ambient temperature.