半导体制冷/制热试验箱性能模拟和调节

微型橡胶材料试验箱拟采用半导体制冷／制热技术进行箱内温度工况的调节和控制,通过建立数学模型、模拟子系统,采用Matlabl／Simulink软件对系统进行性能模拟和调试,得出了几种调节方法下系统主要参数的动态和稳态过程,并简要分析了环境温度对调节参数的影响。模拟方法和结果对于系统设计、系统调试有一定指导作用。     

Control of a Thermoelectric Brain Cooler by Adaptive Neuro-Fuzzy Inference System

Abstract

In this study, neuro-fuzzy control of a thermoelectric head cooler system (thermoelectric helmet) is developed for brain hypothermia applications. Hypothermia is a medical treatment method of protecting the brain, in which the temperature of the brain drops below the critical level for reducing oxygen consumption of tissues. The brain should be kept at a certain temperature by a suitable control for hypothermia applications. The temperature of the thermoelectric head cooler system changes according to the current intensity supplied. The control of the thermoelectric head cooler system was performed according to the initial membership functions, which was determined by an expert using fuzzy logic control. The system was modeled by an adaptive neuro-fuzzy inference system (ANFIS). The data were then entered into the system and new membership functions were determined. By this way, learning ability of the artificial neural network and the abilities of fuzzy logic, such as decision making, were combined and a more effective solution was developed. The system software can be reprogrammed with the new membership functions.     

多级半导体制冷器设计

文中主要介绍了半导体制冷器的基本原理及其应用,并对涉及到多级制冷器的有关公式进行了推导,文章最后得出了关于多级半导体制冷器的一些重要结论。     

应用热电制冷器的微型航天器主动温度控制及仿真

为了改善微型航天器的温度控制效果,介绍了一种应用热电制冷器的主动温度控制系统,建立了这种温度控制系统受控对象及辐射器温度变化的动态特性模型,并对受控对象内部热源功率发生变化时的温度控制效果进行了仿真分析。仿真结果表明：热电制冷器和PI控制器相结合可以简便有效地完成微型航天器内部电子设备的温度控制任务,动态特性模型为这种温度控制系统的优化设计提供了简便的数学模型。     

热压成型装备精密温控研究

为了提高热压装备的温度控制精度,采用热电致冷器作为温度控制的主控元件构建了热压成型系统。针对热电致冷器呈现的复杂热电特性,在对其模型进行小信号线性化的基础上,获得了热电致冷器的控制模型。结合传统PID控制和模糊控制的优点,根据热电致冷器的非线性和可能的不确定性因素,建立PID参数自调整的推理规则,设计了热压成型装备温控的模糊PID控制器。阶跃响应实验表明该温控系统具有良好的动态性能和稳态品质,其升降温速度不小于1℃/s,温控精度可达0.2℃,满足热压成型装备精密温控的要求。     

基于微机电系统技术的微型热电致冷器研究进展

介绍热电材料、热电器件的原理及发展历史,从材料及结构两方面,对基于微机电系统加工工艺的微型热电致冷器的最新研究进展进行综述,比较不同材料及不同结构的性能特点,对块体热电材料和低维热电材料的研究进展进行介绍,着重分析超晶格薄膜材料及Cross-Plane型器件,指出研究具有更高优值系数的新型材料,在维持Seebeck系数不变的同时提高电导率并降低热导率,及采用新的加工工艺优化致冷器的结构,减小接触电阻、接触热阻等,是提高热电致冷器性能的有效手段。     

基于Cortex-M0的半导体制冷温度控制系统设计

冷凝露点法是一种高精度的食品水分活度检测方法,温度控制是其关键技术之一。本设计采用最新型Cortex-M0内核芯片LPC1114作为控制单元,选用半导体制冷器和加热器作为温度控制元件,运用数字PID智能算法进行温度控制。可用于水分活度测量辅助实验,精度高、响应快,取得良好的控制效果。     

Determination of deposit thickness in natural gas cooler based on the measurements of gas cooling degree

An original method for estimating fouled deposit thickness on the inside surfaces of natural gas cooler tubes is presented. This method does not require opening and inspecting a cooler as it is based on the measurement of gas cooling degree, i.e. the gas temperature difference between the cooler inlet and discharge. The deposit layer on the internal heat transfer surfaces is of semi-liquid consistency and its thermal conductivity coefficient has not been investigated until now. This paper describes the experimental determination of the deposit thermal conductivity coefficient. This parameter enables determination of a cooler’s performance as a function of current deposit thickness. Practical application of the method is illustrated in the case of CH_R cooler working in the KS01 compressor station in Vel’ké Kapušany, Slovakia. For this type of cooler, a diagram for deposit thickness as a function of the gas cooling degree is presented.     

基于Cortex—M0的半导体制冷温度控制系统设计

冷凝露点法是一种高精度的食品水分活度检测方法,温度控制是其关键技术之一。本设计采用最新型Cortex-M0核芯LPC1114作为控制单元,选用半导体制冷器和加热器作为温度控制元件,运用数字PID智能算法进行温度控制。可用于水分活弗则量辅助实验精度高、响应陕,取得良好的控制效果。     

废气再循环冷却器的性能仿真及结构改进研究

废气再循环(EGR)冷却器的工作条件恶劣,经常由于热负荷过高而出现结构开裂问题,严重影响实际使用性能。针对某型EGR冷却器,采用流固耦合热分析方法,用计算流体力学和有限元软件计算分析了EGR冷却器的流场、温度场和热应力分布,其数值模拟结果与测试结果吻合;验证了EGR冷却器的开裂现象系工作时所受热应力过高导致。据此,通过在外表面增加扰流槽对EGR冷却器结构进行了一定的改进,试验结果表明,改进后的EGR冷却器不再出现开裂现象,研究结果表明流固耦合分析是解决EGR冷却器开裂问题的有效方法。     

液压系统的热平衡计算与分析

全面分析了液压系统在工作中发热现象的产生机理,冷却器的种类及使用原则,重点介绍液压系统中热平衡中系统发热量计算方法及加热器、冷却器的相关计算方法。     

Four-probe measurements of the in-plane thermoelectric properties of nanofilms

Measuring in-plane thermoelectric properties of submicron thin films has remained a challenging task. Here we report a method based on a suspended microdevice for four-probe measurements of the Seebeck coefficient, thermal conductivity, electrical conductivity, and thermoelectric figure of merit of patterned indium arsenide (InAs) nanofilms assembled on the microdevice. The contact thermal resistance and intrinsic thermal resistance of the 40 nm thick InAs nanofilm sample were measured by using the nanofilm itself as a differential thermocouple to determine the temperature drops at the contacts. The microdevice was also used to measure a 190 nm thick silicon dioxide (SiO(2)) film and the results were compared with those reported in the literature. A through-substrate hole under the suspended microdevice allows for transmission electron microscopy characterization of the nanofilm sample assembled on the device. This capability enables one to correlate the measured thermoelectric properties with the crystal structures of the nanofilm.     

基于光伏充电的高效热电散热系统研究

针对大功率光学器件和设备的热严重影响其稳定性、性能和使用寿命的问题,提出了一种基于能量回馈的智能高效热电散热系统。利用基于改进的增量式比例积分微分（PID）算法快速实现高精度温度控制,通过能量回收机制实现热电制冷器（TEC）制冷效率的提升。采用光伏充电为主、电源充电为辅的电源管理策略,通过上位机监测与控制实现对两组蓄电池的高效充放电切换。同时,利用Python+PyQt5为散热系统搭建可视化图形操作界面。研究表明,设计的实验系统实现了对TEC器件的电路信息监测与温度高效控制,可为解决大功率光学器件和系统的散热问题提供参考。     

热电制冷微型低温恒温器的研究与设计

以热电制冷器为制冷源的微型恒温器,采用热电制冷器进行冷却。用同时限定隔热层外表面的最低温度与单位面积隔热层的漏热量的方法确定隔热层厚度,以同时满足降温阶段冷负荷与稳定工作阶段冷负荷确定制冷量,给出了设计方法。     

纸基芯片温控系统仿真与分析

纸基微流控芯片(μPADs)为聚合酶链式反应、环介导等温扩增提供了新型平台,可用于新冠肺炎病毒检测等领域.为了达到纸基反应芯片所需要的正常工作温度,采用半导体制冷器(TEC)提供反应所需热源,应用有限元仿真软件(FEM)对TEC的整体结构进行建模,依据珀尔帖效应分别对元件中的N型和P型半导体定义并进行热电耦合,同时,研...     

Design of an energy saving oil cooler system using hot gas

According to the development of machine tools to higher speed and multi axes, thermal error which is known to account for about 70% of the total error of machine tools is becoming a serious issue. To reduce thermal error, the heat generating parts of machine tools are cooled down by direct contact with a cooling medium. The medium in most cases is oil, thus, the cooling device is called oil cooler. In this study, an oil cooler system employing hot gas bypass method was developed to improve the performance including energy efficiency of the oil coolers used for ultra-precision machine tools. Through tests, the developed system exhibited high temperature control accuracy of ±0.1°C, and less energy consumption than conventional on/off type (equipped with heater for preventing excessive cooling) by about 45%. The proposed oil cooler system is applicable to semiconductor process, ultra-precision injection molds, as well as ultra-precision machine tools to improve product quality and energy efficiency of production facilities.     

近室温样品加热炉温度的模糊PID控制研究

根据红外隐身材料光谱发射率测试方法的要求,提出了一种基于半导体制冷器的近室温样品加热炉系统。在对加热炉系统特性进行分析的基础上,建立了基于模糊PID控制的系统仿真模型。经仿真及实验可知,在加热和制冷条件下,实际温度与设定温度之间的误差分别为±0.20℃和±1.00℃。结果表明,系统稳定性好,响应时间短,解决了近室温样品加热炉抗干扰能力弱、不易控制等问题。     

间接蒸发冷却器热工计算数学模型及验证

对几种间接蒸发冷却器的热工计算数学模型进行了简要介绍和对比，并对其中两种计算方法进行了实验验证，结果表明周孝清、陈沛霖提出的方法更适用于工程实践。     

A fast ramp rate thermally stimulated current technique to quantify electronic charge dynamics in thin films

Thermally stimulated current (TSC) techniques have been applied to study thermally activated events in many materials. However, the temperature ramp rates in traditional TSC are typically too slow (few degrees per minute) to monitor materials whose properties are strongly time dependent. A fast ramp rate TSC (FR-TSC) technique was developed with ramp rates of 1-5 K/s. This is up to 100 times faster than traditional TSC, so that material changes can be appropriately quantified in the time scale at which they take place. In this paper, the experimental design and challenges to achieve fast and stable ramp rates and to measure the low-level currents are discussed. The fast ramps were attained using a thermoelectric cooler, controlled by a proportional-integral-derivative feedback loop, for both heating and cooling. FR-TSC measurements (1 K/s and 20-100 degrees C) on poly(vinylidene fluoride-trifluoroethylene) ferroelectric thin films are discussed as an example material. From these measurements, thermally activated currents as well as irreversible and reversible charge dynamics were readily distinguished with multiple thermal cycles. These measurements suggest that this technique holds substantial promise in quantifying charge dynamics in fast response materials.     

The mathematical modelling of the impact of electric (Seebeck) effects on end-milling

It is a well-known fact that thermoelectric currents, reaching even the scale of ampere, develop during chip formation in the machine-workpiece-tool-chip. The impact of these currents on tool wear in end-milling was examined with a qualitative thermoelectric model, in which wear is described by an autonomous non-linear differential equation. Cutting temperature was measured by a so-called natural thermoelement with C60 and P35 carbide pair, which were submerged into heated Sn bath at validation. The mathematical model can be solved by a numerical method, where the inverse of the differential equation of wear was used. The wear curves determined by calculation fitted well with the measurement results. The results were achieved by cutting experiments using P35 carbide conducted on the C45 quality steel workpiece. It was found that the optimal solution with respect to the wear of the tool behaving as a natural thermal element might be achieved if the current is compensated by an external power source. Based on the model, anomalies might occur in some cases in the thermoelectric system. Further research is necessary to decide if this is only a special characteristic of the model or the model is interpreting really the actual processes.