高功率激光反射镜变形的半导体致冷补偿的研究

激光谐振腔中的反射镜在激光作用下其镜面产生变形，使反射镜面偏离原设计要求。实验表明，半导体致冷铜镜和硅镜可以很好地补偿激光热变形，使反射镜在承受激光功率的时候，其镜面面型保持不变。此外，半导体致冷镜还有无压力变形、致冷量可控、致冷均匀等优点。     

热电式微波功率传感器的优化设计

提出了一种热电式微波功率传感器的二维热分布解析模型,通过分析传感器的各种结构参数对热分布的影响,给出了热电式微波功率传感器的优化设计.为了获得高灵敏度,给出了设计膜的厚度、匹配电阻与热电堆热端的距离、热电堆悬浮部分的长度等结构参数的原则,并利用Ansys模拟结果和解析结果进行对比验证,结果显示两者吻合较好,说明了解析模型的适用性,可在设计该类传感器时参考.     

热电式微波功率传感器的优化设计

提出了一种热电式微波功率传感器的二维热分布解析模型,通过分析传感器的各种结构参数对热分布的影响,给出了热电式微波功率传感器的优化设计.为了获得高灵敏度,给出了设计膜的厚度、匹配电阻与热电堆热端的距离、热电堆悬浮部分的长度等结构参数的原则,并利用Ansys模拟结果和解析结果进行对比验证,结果显示两者吻合较好,说明了解析模型的适用性,可在设计该类传感器时参考.     

Electric Power Generation from Thermoelectric Cells Using a Solar Dish Concentrator

In this paper, design details, theoretical analysis, and outcomes of a preliminary experimental investigation on a concentrator thermoelectric generator (CTEG) utilizing solar thermal energy are presented. The designed CTEG system consisted of a parabolic dish collector with an aperture diameter of 1.8 m used to concentrate sunlight onto a copper receiver plate with 260 mm diameter. Four BiTe-based thermoelectric cells (TEC) installed on the receiver plate were used to convert the concentrated solar thermal energy directly into electric energy. A microchannel heat sink was used to remove waste heat from the TEC cold side, and a two-axis tracking system was used to track the sun continuously. Experimental tests were conducted on individual cells and on the overall CTEG system under different heating rates. Under maximum heat flux, a single TEC generator was able to produce 4.9 W for a temperature difference of 109°C, corresponding to 2.9% electrical efficiency. The overall CTEG system was able to produce electric power of up to 5.9 W for a 35°C temperature difference with a hot-side temperature of 68°C. The results of the investigation help to estimate the potential of the CTEG system and show concentrated thermoelectric generation to be one of the potential options for production of electric power from renewable energy sources.     

Multi-parameter Optimization of a Thermoelectric Power Generator and Its Working Conditions

The global optimal working conditions and optimal couple design for thermoelectric (TE) generators with realistic thermal coupling between the heat reservoirs and the TE couple were studied in the current work. The heat fluxes enforced by the heat reservoirs at the hot and the cold junctions of the TE couple were used in combination with parameter normalization to obtain a single cubic algebraic equation relating the temperature differences between the TE couple junctions and between the heat reservoirs, through the electric load resistance ratio, the reservoir thermal conductance ratio, the reservoir thermal conductance to the TE couple thermal conductance ratio, the Thomson to Seebeck coefficient ratio, and the figure of merit (Z) of the material based on the linear TE transport equations and their solutions. A broad reservoir thermal conductance ranging between 0.01  W/K and 100 W/K and TE element length ranging from 10^-7 m to 10^-3 m were explored to find the global optimal systems. The global optimal parameters related to the working conditions, i.e., reservoir thermal conductance ratio and electric load resistance ratio, and the optimal design parameter related to the TE couple were determined for a given TE material. These results demonstrated that the internal and external electric resistance, the thermal resistance between the reservoirs, the thermal resistance between the reservoir and the TE couple, and the optimal thermoelement length have to be well coordinated to obtain optimal power production.     

热电式MEMS微波功率传感器的优化设计

为了提高热电式微波功率传感器的传热效率,改善传感器的性能,对热电式微波功率传感器的衬底结构进行了优化设计,得到了最优的衬底结构尺寸。首先研究衬底厚度对热电式微波功率传感器的影响,然后根据得到的最优衬底厚度,研究基底膜位置及尺寸对热电式微波功率传感器性能的影响,最后对所得最优衬底结构传感器的微波特性以及电磁场分布进行研究。结果表明,当传感器衬底的结构尺寸最优时,传感器的最高温度达到352.76 K,S参数小于-20.62 dB。该结构不仅减少了热量在衬底的堆积,提高了负载电阻到热电堆的热传输效率,而且具有良好的微波特性。     

A Novel Optimization Method for the Electric Topology of Thermoelectric Modules Used in an Automobile Exhaust Thermoelectric Generator

Based on Bi₂Te₃ thermoelectric modules, a kind of automobile exhaust thermoelectric generator (AETEG) with a single-column cold-source structure was designed. To enhance its net power and efficiency, the output performance of all the thermoelectric modules was tested with a temperature monitoring unit and voltage monitoring unit, and modeled using a back-propagation (BP) neural network based on various hot-source temperatures, cold-source temperatures, load currents, and contact pressures according to the temperature distribution of the designed heat exchanger and cooling system. Then, their electric topology (series or parallel hybrid) was optimized using a genetic algorithm to achieve the maximum peak power of the AETEG. From the experimental results, compared with when all the thermoelectric modules were connected only in series or parallel at random, it is concluded that the AETEG performance is evidently affected by the electric topology of all the single thermoelectric modules. The optimized AETEG output power is greatly superior to the other two investigated designs, validating the proposed optimized electric topology as both feasible and practical.     

浅议通信机房节能降耗技术

介绍了通信机房节能降耗的几种技术原理,并重点介绍了针对空调节能的几种方法。在此基础上,对各种节能技术的优缺点和适用场合进行了比较和分析。最后总结出应根据通信局(站)特点,选择几种适合该机房特点的节能方法。各种节能技术应相互补充,有机结合。     

A General Model for the Electric Power and Energy Efficiency of a Solar Thermoelectric Generator

A general model for the electric power and energy efficiency of a solar thermoelectric generator is discussed, considering the influences of the input energy, the thermal conductivity, the absorptivity and emissivity of the heat collector, and the cooling water. The influences of these factors on the performance of the thermoelectric device are discussed, considering the thermoelectric generator as a whole, including the heat collector, the thermoelectric device, and the cooling. Results show that high input energy, and high absorptivity and low emissivity of the heat collector, are helpful for obtaining a high-performance thermoelectric generator. A high thermal transfer coefficient of the cooling water can increase the temperature difference across the thermoelectric device but results in greater accessory power requirements if increased further.     

High Thermoelectric Power Factor Near Room Temperature in Full-Heusler Alloys

We present results on the electrical resistivity, Seebeck coefficient, and thermal conductivity for the Heusler alloys Fe₂VAl_1–x Si _x and Fe₂VAl_1–x Sn _x synthesized using standard arc-melting techniques. While alloys with x = 0 are p-type, upon substitution of Si or Sn for Al the alloys can be made n-type with optimized sample compositions exhibiting thermoelectric power factors in excess of that of bismuth telluride near room temperature. The lattice thermal conductivity κ _L of these alloys is too large to produce a high figure of merit; the prospects for and initial attempts at lowering κ _L are discussed.     

Thermoelectric Power of a Luttinger Liquid

Semiconductors - The thermoelectric power of a Luttinger liquid with a potential barrier is calculated. The long-range nature of electron–electron interaction is taken into account. It is...     

电子器件热电制冷温度条件的优化

基于热电制冷热力学循环分析了热电制冷器正常工作的温度条件,以及两种极限工况性能受工作温度条件的制约关系。优值系数是热电制冷器性能的内在制约,散热和温度条件则是热电制冷性能的外在制约,热电制冷元件工作的温度特性与电子元件工作的理想温度条件是非常适应的。基于热电制冷的主动冷却技术对高热流密度电子集成部件的封装散热具有重大意义。     

高精度电流、温度控制器在半导体激光器中的应用

讨论一种大功率激光器控制器的设计方案 ,它能够对激光器提供一个稳定的受控电流 ,并能实时监视、控制激光器的温度 ,以达到保护激光器的目的。以MCS - 5 1单片机为核心的控制器实现了对系统的精确控制 ,对电流的控制达到毫安级 ,温度可达 0 .1℃。     

Development of a Thermal Buffering Device to Cope with Temperature Fluctuations for a Thermoelectric Power Generator

To stabilize the heat input to a thermoelectric generator (TEG) and protect it from large temperature fluctuations, a thermal buffering device (TBD) was fabricated and examined using a typical Bi-Te TEG module and a brand-new Mg₂Si TEG module. The TBD comprises two adjoining heat storage containers, each containing different alloys, which can be optimized for the temperature range of the TEG. The combination of two alloys in series diminishes the thermal fluctuations, stabilizing the heat input to the TEG module. This is achieved by having two metallic materials with large enthalpies of fusion that can be placed between the heat source and the TEG. The combination of the two alloys can be optimized for the temperature ranges of Bi-Te, Pb-Te, or Co-Sb. For the Bi-Te TEG, 15Al-85Zn and 30Sn-70Zn alloys were used for the heat source side and the TEG side, respectively. The corresponding alloys for the Mg₂Si TEG were 20Ni-80Al and 7Si-93Al. With the use of a TBD, the Bi-Te TEG exhibited no notable damage even in the rather high temperature range beyond ??573?K. For the Mg₂Si TEG, no operational damage of the Mg₂Si TEG module was observed even with a temperature of 1020?K.     

节能降耗中电力计量技术的应用

本文重点对节能耗电中国电力计量技术应用的必要性和现状进行了阐述.     

安徽电力地县一体化SDH设备网络结构优化方法

随着安徽省电力通信网的不断建设,SDH设备(Synchronous Digital Hierarchy,同步数字体系)作为传输承载网,网元数量在不断扩大。如何增强网络安全,提高工作效率,优化传输性能,成为通信网建设和改造项目需要考虑的核心要素。文章以安徽省A市为例,基于现有网络状况,从承载网的安全、效率、性能等方面分析,通过拓扑优化,分析优化前后网络可靠性、传输效率、传输性能的不同。提出基于地县一体化SDH网络结构的优化方案。     

GPU集群能耗优化控制模型研究

随着大数据技术的发展,GPU集群作为一种高效的并行系统被应用到大规模数据实时计算中.能量是实时计算时重要的资源,GPU集群的能耗优化及实时消减成为一个具有挑战性的问题.从集群全局角度引入模型预测控制策略,并建立闭环反馈机制的多输入多输出控制器.通过调整计算频率和改变活跃流多处理器来改变能耗状态,利用反馈和滚动优化机制完成对未来的控制预判,实现消减冗余能耗的目标.实验表明:控制模型的精度和节能效果优于基准模型,而且具有较好的稳定性,适合应用到大规模数据实时计算中.     

血液冷藏箱温度监测系统研制

基于嵌入式微控制器设计了一种血液冷藏箱的温度采集、控制系统。依据血液冷藏的实际需求,详细叙述了血液温度监测与压缩机控制系统的实现思路,以及主要部分的软、硬件实现。采用嵌入式操作系统实现任务切换和数据采集与处理,使得血链装备具有可靠、便携和实用性特点。     

Optimization of Peak to Average Power Reduction in OFDM

Orthogonal frequency division multiplexing (OFDM) a multicarrier system [1, 2] provides base for all advanced wireless communication system. The performance of OFDM is degraded by peak-to-averagepower ratio (PAPR). High PAPR requires high power amplifiers (HPAs). The nonlinearity of the HPA exhibits amplitude and section distortions, that cause loss of orthogonality among the subcarriers, and hence, intercarrier interference (ICI) is introduced inside the transmitted signal. Not only that, high PAPR put together lands up in in-band distortion and out-of-band radiation. Rather than using HPA’s, the only way to improve performance of OFDM system is to reduce PAPR. The PAPR reduction of OFDM system gives fair reduction in PAPR under partial transmits sequence (PTS) and DCT-SLM techniques. Here in this paper we proposed a combination of PTS and DCT-SLM and an algorithm to cut back the PAPR. This hybrid combined technique reduces PAPR effectively and minimizes the complexity of PTS technique.     

功率控制器结温无损伤测量技术研究与实现

固态功率控制器或固体继电器逐步向大功率方向发展,其结温测量与监控成为工程应用中的难题,针对这类具有输入输出隔离功能的器件,采用等功率结温测试法研究了基于MOSFET的功率控制器结温无损伤测量技术。利用MOSFET自身结构,通过研究寄生pn结电压随温度变化规律、器件正向功率和反向功率关系、等功率结温测试与实际结温测试结果对比,提出了适用于工程应用的结温无损伤测量方法。结果表明,采用本方法测试结温准确度在1%以内,并可有效避免器件时间差、测试时间差等问题,可实现多层结构、非气密结构等传统方法难以实现的结温测量,具有良好的工程应用价值。