Design And Implementation Of Constant Temperature Control Box Based On Semiconductor Refrigerator

Semiconductor refrigeration(thermoelectric refrigeration)and mechanical compression and absorption refrigeration and known as the world’s three biggest refrigeration,mechanical compression and absorption refrigeration of the most widely used,but in the special fields such as medical,biology,experimental research,its complex structure,difficult to precise control,easy to produce the defects such as pollution,severely restricting the semiconductor refrigeration cooling fast,pollution-free characteristics,has good applicability.This topic USES semiconductor refrigeration to adjust the temperature of small space,in order to develop and realize a constant temperature control box based on semiconductor refrigeration,so as to make semiconductor refrigeration more suitable for the field of high-performance small space temperature control.For this purpose,this paper conducts in-depth research on its key technologies.The main contents are as follows:(1)Through the research and analysis of semiconductor refrigeration,thermostatic control and other related theories and practical applications of semiconductor refrigeration,a set of reasonable design scheme is developed,including clear design index,box structure design and analysis,hardware control circuit construction and software algorithm design.(2)Under the guidance of the overall scheme,the paper conducts in-depth analysis and numerical calculation of the research results such as temperature field simulation,and completes the design of the box: selection of materials,refrigerating sheet position and loose cooling mode,calculation of thickness and thermal load,etc.The results of structural analysis and overall test show that the designed box has sufficient cold diffusion,good insulation and low temperature stability for a long time.(3)With the modular design concept to achieve the hardware control board construction: 51 single-chip microcomputer as the core,supplemented by DS18B20 sensing,setting,display and drive functions,with simple and easy to achieve,anti-disturbance reliable characteristics.(4)Aiming at the system control scheme design of semiconductor refrigeration,the system model identification,Simulink simulation construction and step input comparative analysis were mainly carried out by computer aided design method.Compared with common PID control,the designed fuzzy self-tuning incremental PID algorithm has the best control effect——no overturning in simulation,zero steady-state static difference and 87% anti-interference.(5)On the basis of the previous work,the system sequence flow chart was analyzed and planned,and the software and hardware download and adjustment were guided to complete.Finally,the experimental test results show that the steady-state precision of the designed temperature control box is within ±0.2℃,and the micro-overdose is 0.24℃ in the time-varying environment.The adjustment speed,steady-state volatility and adrc all meet the design requirements.