Two‐Degree‐of‐Freedom Robust Temperature Control of Peltier Device Based on Heat Disturbance Observer

Recently, the Peltier device has been attracting attention as a haptic device that can transfer heat, because it has relatively fast response characteristics among thermal devices. To transmit thermal sensation, temperature control is considered to be important. However, it is difficult to design a controller because of factors such as parameter variations, nonlinear characteristics of the device, and heat that flows from an external object. Furthermore, it is preferable that the tracking performance and disturbance suppression characteristics be designed independently. To address these factors, this paper proposes a heat disturbance observer, which is constructed by using the disturbance observer commonly used in the field of motion control. When the observer is used, the thermal system becomes robust to the above‐mentioned factors. In addition, it is possible to design the tracking performance independently of the disturbance suppression characteristics. The validity of the proposal is confirmed by experimental results. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(1): 66–74, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22282     

Characterizing a Thermoelectric Module as Part of a Semiconductor Course Laboratory

Thermoelectric modules (TEM), also known as Peltier modules, form an interesting topic to cover in an introductory semiconductor course. They provide insight on some important semiconductor principles, namely the Seebeck effect (the reverse of the Peltier effect) and thermal conductance. This paper presents a new methodology to characterize a TEM using a custom-designed test apparatus along with a simplified method for determining the TEM's three key parameters: its Seebeck coefficient, its electrical resistance, and its thermal conductance. Results obtained using this methodology were validated by comparing the anticipated theoretical behavior of the TEM (using the experimentally determined parameters) to the actual results obtained in a vacuum environment. The suggested methodology has been evaluated by students and the results of this demonstrate its usefulness in an educational environment.     

Lattice Temperature Model and Temperature Effects in Oxide-Confined VCSEL’s

A lattice temperature model is derived for oxide-confined vertical cavity surface emitting lasers (VCSELs) based on carrier transport and the conservation of energy. Peltier heat is caused by the bandedge and quasi-Fermi level discontinuities at a heterojunction. However, considering the device size, Peltier heat needs to be distributed and is not just generated at the interface, otherwise, an anomolous spike in temperature will occur. We have developed a novel treatment to model the Peltier heat at a heterojunction by use of a Monte Carlo simulation. Peltier heat is found to be a major heat contributor, and it results in a rapid and high temperature rise in the separate confinement heterostructure (SCH) region of the laser diode. We have also shown that the carrier thermal conductivities for materials with high mobilities must be included at high carrier densities because they contribute to additional spreading of the thermal energy. Subsequently, this lattice temperature model is coupled self-consistently to electronic and optical solvers to form a complete simulator for VCSELs. Self-heating causes a fast temperature rise when the VCSEL is operated under continuous wave conditions, causing resonant wavelength changes and an eventual thermal rollover. The resonant wavelength shift has been shown to be caused mainly by the heating of the distributed Bragg reflectors even though the peak temperature occurs within the SCH region. Possible physical factors causing the thermal rollover have also been examined with our complete simulator. The Auger recombination process is found to be one of the main factors causing the thermal rollover in 980 nm oxide-confined VCSELs while the photon lifetime is a factor in determining the position of the thermal rollover. We have also achieved a very good match between our simulated results and experimental data.     

Thermal resistance network model for heat sinks with serpentine channels

Serpentine channels in liquid cooling have received considerable attention for their high heat transfer coefficient and potential applications in high heat flux electronics. In this paper, a simple thermal resistance network model is proposed to simulate the thermal performance of heat sinks with serpentine channels. The model comprises a series of thermal resistance units connected by flow networks, which display the temperature and pressure distribution between units. By varying the Reynolds number of the fluid and the aspect ratio of the channel, temperature and pressure results of a 10‐channel serpentine heat sink are obtained and subsequently compared with full three‐dimensional computational fluid dynamics simulations. The results demonstrate that the model can predict the heat transfer characteristics of serpentine channels with high accuracy and significantly less computing time. Copyright © 2013 John Wiley & Sons, Ltd.     

Analytical modelling of multilayer structure electronic devices for electrothermal layout optimisation

In this paper, an analytical model for the electrothermal solution to the non‐linear 3‐D heat flow equation for multilayer structure electronic devices is proposed. Compared with previous models presented in literature, it is general and can be easily applied to a large variety of integrated devices, provided that their structure can be represented as an arbitrary number of superimposed layers with a 2‐D embedded thermal source, so as to include the effect of the package. The proposed method is independent of the specific physical properties of the layers, hence GaAs MESFETs and HEMTs as well as silicon and silicon‐on‐insulator MOSFETs and heterostructure LASERs can be analysed. Moreover, it takes into account the dependence of the thermal conductivity of all the layers on the temperature; the heat equation is solved coupled with the device current–voltage relation in order to give physical consistence to the experimental evidence that a temperature increase causes a degradation of the electrical performances and that the electrical power is not uniformly distributed. Copyright © 2001 John Wiley & Sons, Ltd.     

环境风对火电厂直接空冷系统热回流影响的研究

本文利用Fluent软件对某火电厂2×1000MW机组直接空冷系统流场进行数值计算,研究了热回流率随环境风向和风速的变化规律以及挡风墙高度对热回流率的影响。计算结果表明:直接空冷系统的散热性能对周围风环境很敏感,特别是从锅炉房和间接空冷塔方向来流时,大风对空冷岛的散热效果影响较大;其他风向下,随着来流风速增加,热回流率先增大后减小;适当增加挡风墙高度,可以有效降低热回流率。     

Effects of back cooling with Peltier devices on thermoregulatory responses in a hot environment

To prevent individuals with thermoregulatory dysfunction from becoming hyperthermic in a hot environment, we propose a back‐cooling (BC) system with Peltier devices mounted on a wheelchair backrest. Here, we characterize the changes in thermoregulatory responses induced by BC in order to confirm the feasibility of the proposed system. A cooling experiment in a climate chamber at 33°C with six able‐bodied subjects demonstrated that the amount of sweating and systolic blood pressure were significantly lower in the BC trials than in the no‐cooling trials, providing preliminary evidence that BC can partially replace thermoregulatory responses and reduce the heat burden. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Modelling DC characteristics of GaAs MESFETs in a wide range of temperatures

In this paper, a new semiempirical DC thermal model of low‐ and high‐power GaAs MESFETs is proposed. The model takes into account the effect of device negative output conductance and simulates external thermal effects modelling the dependence on temperature of the device threshold voltage and the maximum saturation drain–source current. A number of GaAs MESFETs, very different from a geometrical and technological point of view, have been characterized as a function of temperature and modelled by our model with high accuracy. The CPU extraction time results are moderate in any example. Results have been compared with the Rodriguez–Tellez model, showing improvements of accuracy better than 30 per cent. The model can be successfully used n MMIC CAD applications. Copyright © 2001 John Wiley & Sons, Ltd.     

Fundamental characteristics of a MEMS‐diaphragm actuator using a thermal expansion drive composed of a conductive polymer

Performance of a MEMS actuator using a thermal expansion drive of a conductive polymer (CP) is investigated by applying electricity to it. The actuator consists of a thin polymer diaphragm (5 mm diameter) and a thin CP (ion‐doped polythiophene) layer coated on the diaphragm surface. Polyimide (10 μm thickness) and PET (110 μm thickness) sheets were chosen as the diaphragm materials. The diaphragm is deflected by the thermal expansion of the CP by applying electricity to it. Merits of using the CP instead of metal are realizing flexible actuators and the applicability to a low‐heat‐resistant material diaphragm. The relationship between thickness of the CP layer (10–50 μm thickness) and electrical resistance (30–600 Ω) and the relationship between the input voltage (1–8 V) and the generated diaphragm displacement (several tens of micrometers) were investigated experimentally. These relationships were compared with those in the case of using the thermal expansion of a vapor‐deposited aluminum layer (0.1 μm thickness). The results of the investigation indicate that the diaphragm based on CP can produce the required displacement. In the case the CP‐layer‐based thermal expansion, however, larger input voltage than in the case of the aluminum‐layer‐based thermal expansion is needed to obtain the same displacement amplitudes. Therefore, the main problem concerning use of the CP‐based diaphragm is considered to be enhancing the electrical conductance of the CP layer. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

输电线路动态热定额技术的应用

输电线路静态热定额计算, 采用特定的环境温度和风速, 比较保守。而输电线路动态热定额计算,采用实时的导线温度和气象数据, 实时反映了线路动态热容量的情况。同时在线路上配置实时监测装置和小气象站, 为调度运行人员控制线路负荷提供依据。采用动态热定额能提高线路输送容量10%～30%, 是一种廉价、有效、安全的线路增容技术。     

新型平板热管相变蓄热器蓄放热性能分析

采用石蜡作为蓄热换热介质,将新型平板热管作为换热元件以强化换热,并在平板热管两侧平面添加纵向翅片,设计了一套热管式相变储热换热器实验装置,对相变蓄热换热器的蓄、放热特性进行了实验研究。测定了石蜡的温度分布随时间变化的规律;改变充、放热流体工况,分析了不同流量和流体温度对蓄放热过程的影响。通过分析发现,新型平板微热管阵列在相变蓄热器的蓄放热过程很好地发挥了强化传热元件的作用,蓄热过程中,传热流体温度越高,相变材料的熔化速率也越大;放热过程中,相同的流体温度下,随着流体流速的增大,蓄热器的放热速率逐渐增加。实验结果表明,新型平板热管蓄热器蓄放热效果良好。     

500 kV充油海底电缆运行状态综合在线监测系统研究

海南联网系统500 kV海底电缆运行环境复杂多变,会直接影响到海底电缆的运行状态.为了有效掌握海南联网系统三相31 km海底电缆的运行状态,研究充油海底电缆运行状态综合在线监测技术至关重要.文中根据海底电缆实际运行监测要求,结合充油海底电缆捆绑通信光缆的这一特殊结构,开展了基于布里渊光时域分析的分布式光纤温度传感技术研究,建立了基于IEC 60287热路模型的充油海底电缆的温度热场分布的热路模型,研制了500 kV充油海底电缆运行状态综合在线监测系统,完成了系统的现场安装及挂网运行.该系统能实时监测海底电缆的温度、油流以及油压等运行参数,通过海底电缆温度、油流以及油压历史数据分析,表明系统可实时监测海底电缆的运行状态及稳定可靠运行.     

用ANSYS软件包模拟半导体器件散热器稳态热阻

介绍了ANSYS多物理场软件包的流动传热仿真分析特点、功率半导体器件用的散热器稳态热阻的理论分析及计算仿真的基本过程。所得出的一系列仿真结果与实验数据是吻合的，证明了仿真理论的正确性。     

基于热真空环境模拟试验技术的信号电缆热防护方案研究

热真空环境模拟试验是在地面上模拟飞行中施加在飞行器表面热载荷的一种方式，为了模拟 “高真空”和“高热流”环境，利用石英灯阵作为热源，基于热学理论分析和计算，设计并实现了一套热真空环境模拟试验及测控系统方案。航天器电缆热量过高会造成电缆损坏，影响整星安全，利用热真空环境模拟系统设计并进行了真空环境下的信号电缆隔热材料包覆方案考核试验，对热防护方案进行了试验验证，并得出了满足温控要求的热防护方案。试验结果证明，镀铝薄膜隔热层的热防护效果较好，能够满足航天器对信号电缆的热防护需求。同时，该热真空环境模拟试验系统也为热防护方案的试验验证提供了必要的技术手段。     

计及电缆热特性的电热耦合潮流计算

将交联聚乙烯绝缘电缆热平衡方程与电网潮流模型有机结合,构建计及电缆热特性的电热耦合潮流计算模型,实现将架空线路、电缆导体、金属护套以及外护套的温度纳入潮流计算状态量,并在牛顿法修正方程基础上结合高压电网及电缆热平衡方程特点提出该模型的快速解耦求解方法。作为电热协调理论研究的扩展,文中研究能够计算各种预想电网运行模式下架空线路及电缆温度轨迹,有利于在电网分析及调度决策中实现对电缆载荷能力的科学评价及高效利用。     

Multilayer thermal object identification in frequency domain using IR thermography and vector fitting

This paper deals with the identification of the thermal parameters of multilayer objects using the concept of thermal impedance. In order to perform such identification, temperature evolution in time is obtained by an infrared camera after power excitation is applied in the investigated structure. Infrared thermography offers the advantage of being a noncontact temperature detection and measurement method. In many practical cases, it is impossible to use contact temperature measurements. Typically, the power in the form of a step function is applied. In order to calculate the thermal impedance of an object, temperature and power are converted into the frequency domain using the Laplace transform for s = jω. Then, the poles of the thermal impedance are identified using vector fitting, which allows calculating the thermal impedance as a sum of partial fractions. This corresponds directly to the Foster network of a thermal object. In addition, the vector fitting method offers much better convergence in comparison with other methods using the polynomial rational approximation of thermal impedance. A considerable improvement of the numerical Laplace transform in high frequency range is proposed. In this approach, the variable s = jω is replaced by , and then, the integration result is corrected by the Taylor series. It leads to a kind of filtering of the temperature signal.     

三芯海底电缆中复合光纤与导体温度关系建模

三芯光纤复合海底电缆中光纤以内填充层热阻的准确计算是建立光纤与导体温度关系的关键和难点。本文在建立三芯海缆热路模型的基础上,根据虚拟热源和镜像法,利用光纤温度计算出填充层外径处温度,进而计算出铠装层外径处温度;根据傅氏传热学原理计算出光纤处等温面至铠装层外径处等温面的热阻;利用形状因子法计算出填充层内径至铠装层外径的总热阻,再减去光纤处等温面至铠装层外径处等温面的热阻,得到光纤以内填充层的热阻;根据热路模型建立了光纤与导体的温度关系方程,并用有限元求解结果验证了方程的正确性。结果表明,三芯海缆的光纤与导体温度呈线性关系,导体温度每上升1.15℃,光纤温度上升1℃;相同导体温度下,环境温度每上升7.7℃,光纤温度上升1℃。根据光纤温度和环境温度可计算出导体温度,作为三芯海缆导体温度监测和载流量计算的理论依据。     

A fast power loss calculation method for long real time thermal simulation of IGBT modules for a three‐phase inverter system

A fast power losses calculation method for long real time thermal simulation of IGBT module for a three‐phase inverter system is presented in this paper. The speed‐up is obtained by simplifying the representation of the three‐phase inverter at the system modelling stage. This allows the inverter system to be simulated predicting the effective voltages and currents whilst using large time‐step. An average power losses is calculated during each clock period, using a pre‐defined look‐up table, which stores the switching and on‐state losses generated by either direct measurement or automatically based upon compact models for the semiconductor devices. This simulation methodology brings together accurate models of the electrical systems performance, state of the art‐device compact models and a realistic simulation of the thermal performance in a usable period of CPU time and is suitable for a long real time thermal simulation of inverter power devices with arbitrary load. Thermal simulation results show that with the same IGBT characteristics applied, the proposed model can give the almost same thermal performance compared to the full physically based device modelling approach. Copyright © 2006 John Wiley & Sons, Ltd.     

环境温度及风速对LED照明产品散热的影响分析

LED照明产品大多采用自然对流冷却（散热）方式。相对于强制对流冷却方式,自然对流冷却的电子产品其辐射换热量所占比例较大,其散热受环境风速的影响也较大。借助于热仿真方法,详细分析了环境温度（对热辐射影响较大）及风速对自然对流冷却LED照明产品散热的影响,对LED照明产品热分析及热测试具有重要的指导意义。     

Adaptive repetitive control for resonance cancellation of a distributed solar collector field

This paper deals with modelling and control of the outlet temperature in a distributed solar collector field. The resonance dynamics characteristics of this kind of system are similar to those of tubular heat exchangers in the closed‐loop system bandwidth when fast responses are required. Simple low‐order rational models are unable to capture the resonance dynamics, which can be excited by changes in both the heat transfer fluid flow and solar irradiation. This paper proposes a new model derived from a similar model for a tubular heat exchanger. This model allows the use of low‐order controllers, which can be extended to an adaptive control scheme to account for varying resonance frequencies, as a new functionality achieving fast, well‐damped responses. Copyright © 2008 John Wiley & Sons, Ltd.