The Research Of Vehicle Air-condition System Based On Variable Displacement Compressor

As improving of people's material and living standards,it is more demanding that the demand of comfort when you are driving a car.At the same time,with the proposed new requirements and index of comfort,the vehicle system is intelligent,the development cycle is fast,the operation of the control system stability,have higher requirements.Therefore,how to carry out more details of the system,how to reduce the cost and shorten the development cycle has become the major which automobile manufacturing enterprises and scientific research institutions are concerned about.Based on the study of vehicle air conditioning control system of variable displacement compressor based on the analysis,through experimental verification of its control rapidity,accuracy and stability,can make the control system and its development process has been widely used.First of all,the basic structure of the vehicle air conditioning system and the refrigeration principle is analyzed.Then the achievement of vehicle air conditioning system condition analysis,elaborated the passengers and the demand of system manufacturers.And several air conditioning systems in the past,the system is decided by the system with variable displacement compressor as the main control object,and the rest control strategy is to adjust and supplement the system structure of the variable displacement compressor;Secondly,this paper introduces the module of refrigeration system,air supply system,and through the resolution of the module,combined with the components mentioned above,especially introduces the compressor,condenser,evaporator,expansion valve,mixing damper,physics structure analysis and the use of each device.The method of power bond graph simulation software AMESim based on physical system modeling;based on the model established the system diagram,and the open loop system is analyzed,to decouple the coupling part and use the PI controller.And its optimization,puts forward three kinds of anti-windup methods,and finally adopts clamping method;compensation for different interference,put forward the concept of the target air outlet of HEBA,and joined the feedforward control,the system has two closed loop,was solved by the system.The interference problem caused by the volume of art,the establishment of control system simulation model;modeling of the control part by using the simulation software AMESim,the influence of two different solving mode of simulation,and the requirements of the system is verified by simulation The rnntrtrol(?)Matlab,the feasibility of the joint simulation is verified by experiment,and the control system is converted to C code by its own real-time workshop tool kit;Finally,the hardware structure design of air conditioning controller to Freescale's S9S12GN48 as the main processor chip of vehicle air conditioning and conversion to complete the C code in the burning;for air conditioning controller and test bench was set up,and through the change of asynchronous motor current recording ACS510 converter shows the value of the data,and the host computer panel,by measuring the carriage side parameters,control effect verification system in the actual stand in.After experimental verification,the design of the air conditioning control system simulation model to meet the requirements on speed disturbance,can turn the simulation temperature inside the car which is controlled within the set temperature of ±? and the joint simulation,C code conversion can be successfully programmed,the platform to control the air temperature.Precision within ±1?,it is proved that this system has good rapidity,accuracy and stability,meet the requirements of practical application.