Development Of Double-effect Lithium Bromide Absorption Refrigerator And Its Control System Based On Micro Turboshaft Engine

The lithium bromide(Li Br)absorption refrigerator has the advantages of environmental friedliness,high reliability and stability.And it has been more and more studied and applied in academia and industry.In this thesis,a Li Br absorption refrigerator with 8k W refrigeration capacity is taken as the object of research and design,which mainly involves four aspects: scheme design,modelling and simulation,control system design and hardware-in-the-loop test.First,based on the discussion of the solution property,working principle,circulation mode and composition structure of the Li Br absorption refrigerator,the demand analysis of the refrigerator and its control system based on micro turboshaft engine was carried out.Secondly,the architecture of the double effect,three-cylinder absorption refrigerator with 8k W refrigeration capacity was proposed.The thermal/heat transfer calculations were carried out for the design points of the key components.Based on MATLAB / Simulink,the steady-state mathematical model of the Li Br refrigerator was established.Furthermore,the physical structures were designed and the strengths of the structures were checked based on Solid Works.Thirdly,the control system of the refrigerator was designed.The sensors and actuators were selected.The electronic controller adopts cortex-m4 core,with 20 channel sensor signal input,2 channel control signal output(controlling the Li Br solution pump and the circulating water pump),provide communication interface with upper computer.Based on the NI Multisim software,the sensor signal conditioning circuits were simulated and verified.With the Keil 5 development environment,the control software was designed.Afterwards the electronic controller prototype was made and debugged.Finally,the hardware-in-the-loop simulation tests were carried out.The experimental system mainly includes five parts: monitoring computer,electronic controller,interface simulator,signal conditioning drive unit and refrigerator model computer.The simulation tests of starting process,stopping process and regulating process were carried out respectively,and thus the effectiveness of the controller was verifyed.