压电风扇与散热器组合系统的散热性能及其改进

为提高散热器的散热性能,将压电风扇分别与直肋和针肋式散热器组合进行散热,利用FLUENT软件仿真其散热流场并计算其协同角,分析2种散热器的散热性能特点。考虑压电风扇的振动特性,将直肋式散热器的肋片改为扇形布置,并根据仿真结果进一步将该散热器扇形肋片的后端改为针肋,设计新型散热器。根据散热器温度和协同角分布对散热器的散热性能进行评价分析,结果表明：自然散热时,针肋散热器的散热性能最好,且协同角相对较小;当压电风扇工作时,新型散热器散热性能最好,可比原直肋散热器组合温度降低4 K,比原针肋散热器组合温度降低2 K。新型散热器仅通过改变散热器的肋片布置即可明显改善散热器的散热性能。     

整流器件热分析及其风冷散热器的仿真研究

研究整流器优化散热结构设计问题,对电力变换装置小型化和高功率密度要求越来越严格,功率器件散热技术研究和分析变得尤为重要,针对散热器结构散热性差,影响工作的稳定性.为了能够直观和准确地获得散热器温度场的分布特性,根据传热理论建立了整流器件散热的物理模型,采用了热分析方法(有限元法),应用ANSYS软件对风冷散热器温度场进行了数值计算.计算中考虑了整流器件在风冷散热器上的整体布局,着重对两种肋片形状的风冷散热器进行了仿真,结果对比两种风冷散热器的传热效果.给出了风冷散热器优化设计后的实际结构,为散热优化提供了参考.     

加固计算机肋片散热器的优化设计

当前许多已投入使用的肋片散热器价格较贵,将其安装在发热量很大的COM Express（COM-E）主板上,在55℃高温工作环境下散热效果不理想。针对商用散热器的不足,本文对COM-E主板肋片散热器进行研究,提出单个肋片热阻的计算方法,并根据COM-E主板的发热量,结合热设计相关计算和仿真,设计优化出一款性能优良的通用型肋片散热器。使用优化后的肋片散热器,加固计算机在高速工作的情况下,顺利通过了高温试验。     

一种低成本的新型步进电机驱动器的研制

开发了以单片步进电机控制器L297为控制核心，采用由晶体三极管和功率MOS管组成的分立式的功率驱动电路，以及以单片电流型脉宽调制（PWM）控制器S19114A为核心的高频开关电源电路构成的通用新型两相混合式步进电机驱动器。分析研究了系统的总体结构以及其中关键电路的工作原理和实现。通过实际测试和使用．证明该系统具有宽范围单一电源输入的特性，通用性强、可靠性高，并且成本低廉，可广泛应用于小型机电一体化设备中。     

基于ICEPAK的液冷冷板散热结构的优化设计

以某雷达T/R组件的液冷散热为研究对象,通过分析比较仿真结果,对原冷板流道结构进行优化,在流道内分别增加方柱型和圆柱型两种散热齿。利用实验对这两种方案进行验证,实验与仿真结果的误差小于2%。结果表明：散热齿的引入显著改善了冷板的散热效果,方柱型散热齿的散热效果更优于圆柱型。优化后的两种流道方案均能满足此次冷板热设计要求。综合分析,最终选择圆柱型散热齿的流道结构,方柱型散热齿可以应用于热流密度更高的电子设备热设计中。     

80nm制程的廉价GeForce 7600 GT 双敏速配PCX7628GTe显卡

双敏推出的这款GeForce 7600 GT显卡，型号是“速配PCX7628GTe”，采用非公版 绿色PCB设计。散热部分使用了飞酷静音风扇，拥有46片散热鳍片，大大增加了散热片的表面积，从而提升了散热效果。开放式的散热结构，不仅可以为显卡核心散热，同时也能照顾到业存及发势量较大的MOS管。散热风扇采用的是静音风扇，采用日系NMB滚珠轴承，具有寿命长，噪音低等优点。     

一种相控阵天线强迫风冷热设计方法

阵面温度控制是相控阵天线结构设计的关键技术之一。文中针对某相控阵天线的热设计要求,设计了一种用于相控阵天线散热的强迫风冷系统,并采用数值分析方法,对该系统作用下的相控阵天线阵面热性能进行了分析。对不同流道参数、散热器参数和冷却气体流速下的阵面温度和流体压力进行了仿真。仿真结果表明：冷却气体温度和速度对散热效果影响显著,增加散热片的肋片数量和高度能够提高散热性能。以仿真结果为依据,对相控阵天线的结构参数进行了优选。进行了对比实验,验证了仿真计算的有效性。     

特别照顾VRM的散热器——华硕VR Guard

华硕公司近期推出了一款CPU散热器，对应当前所有的主流平台。它同样采用了类似于AVC龙骑士的侧吹式结构设计，不过与传统CPU散热器不一样的是，它不但可以完美地解决CPU散热问题，更特别对主板电压调节模块（Voltage Regulator Module，VRM，主要由MOS管、电容和电感构成）的散热问题做了特殊设计，因此它被华硕称作“VR Guard”（VR卫士）。     

游戏神将影驰GTX260＋黑将版显卡实测

影驰GTX260＋黑将版显卡给人的第一印象就是那个酷似抽油烟机的巨型散热器。它搭配有三个智能静音风扇,同时还在散热片中加入了五根纯铜导热管。这还不算完,产品还配备了独立显存散热片、MOS管散热片。该显卡荠未使用公版设计,     

潮流硬件

U90给人的第一眼感觉就是硕大精致,金黄色的全铜散热片、蓝色的铝制外壳、淡蓝色的透明水晶风扇相当漂亮。侧面看去,U90采用的是一款规格为8025的风扇,不仅工作噪音小,风量也达到了44CFM,U90在后面还预留了一个抽风风扇的固定位置。散热器底部与处理器接触的地方非常光滑,底部与散热片之间设计用的散热鳍片也很巧妙,可以进一步加强散热效能,每个侧面3根热管,传递热量更加迅速。这款U90散热器的鳍片非常薄,而且还很密,数量达到了27片之多,而且锯齿形的边缘还可以减小风的阻力,带走更多热量。超频玩家必备Snow m an U90散热器流行指数:★…     

整车环境下加装散热翅片对轮毂电机散热性能的影响

为提高电动车轮毂电机散热性能,在整车环境下采用CFD数值计算方法,对不同车速下轮毂电机的散热性能进行数值计算并分析;研究加装散热翅片对轮毂电机散热性能的影响,得到轮毂电机的温度场、空气质量流量、外流场和表面对流传热系数.结果表明：电机的最高温度位于定子上,外表面最高温度区域分布在电机的侧面外壳上;在电机侧面外壳上加装散热翅片可以对电机起到较好的降温效果,当翅片长度方向与电机轴中心线成30°夹角时,更加有利于电机的散热.     

基于最优控制策略的逆变器散热结构优化

为了提高电动汽车用永磁同步电机逆变器IGBT模块的可靠性,文章从热损耗和散热两方面对逆变器可靠性进行研究。首先通过对比分析永磁同步电机在同一工况下d轴电枢电流为零(id=0)和最大转矩电流比(MTPA)两种控制方式下逆变器中IGBT模块的损耗,发现MTPA控制策略优于id=0控制策略;接着,基于MTPA控制策略,设计了一种热管和风冷相结合的散热结构,相较原风冷散热结构,采用新型散热方式可使芯片最高工作温度降低8.49℃;最后,采用最优拉丁超立方抽样构建响应面代理模型(RSM),并采用多岛遗传算法(MIGA)对代理模型进行优化处理。经仿真验证,优化处理后的“热管+风冷”散热结构使得芯片最高温度又降低了15.12℃,有效提升了IGBT模块的热可靠性。     

具有同步续流的电动车用直流电机控制器设计

由于直流电机控制器是电动车中的核心部件,又是故障率最高的部件,其损坏的主要原因是车辆持续重载运行时控制器功耗过大,而控制器通常又都安装在较密闭的空间里,通风不良,散热条件差,若功耗大就会造成温度快速升高,容易发生过热损坏。针对当前直流电机控制器续流损耗大、效率低的问题,提出了基于同步续流的直流电机控制系统设计方案,通过Matlab建立系统仿真模型,进行相关仿真研究来验证方案的可行性,大量的仿真研究结果证明了设计方案的正确性。     

Simulation of a high-power LED lamp for the evaluation and design of heat dissipation mechanisms

High-power LED lamps have been under intense development in recent years. However, issues related to heat dissipation on the LED chip continue to plague research efforts. Heat generation increases with the power of the LED chip and heat accumulation is exacerbated by the plastic casinge of the lamp. Accumulated heat can seriously shorten the lifespan of an LED device. Consequently, manufacturers are constantly seeking ways to improve heat dissipation via heat transfer mechanisms. Little analysis has been performed on coupling the fluid field and heat dissipation inside LED lamps. Using FLUENT software, this study developed a simulation method for LED lamps in order to investigate thermal and fluid fields inside a lamp. The simulation results of an 8 W LED lamp predicted a chip temperature of 75.1 °C and maximum air velocity of 97.3 mm/s within the lamp with two sets of air circulation. The proposed model facilitates new fin designs and the determination of the optimal inner-shell thickness with the proposed design of a LED lamp having 36 fins and an inner-shell thickness of 1 mm for increased heat dissipation.     

HPS整流管芯片散热效率计算仿真研究

针对传统散热效率计算方法存在计算时间过长、计算效率过低以及计算误差偏高等问题,提出了一种新的散热效率计算方法———基于傅里叶导热方程的散热效率计算方法。通过对高功率半导体整流管芯片进行分析,引用傅里叶导热方程计算出整流管芯片的传热热阻,根据传热热阻随着温度的变化,获取高功率半导体整流管芯片散热系数。根据高功率半导体整流管芯片散热系数,构建高功率半导体整流管芯片散热模型,利用建立的模型分析转速、冷气流入口的压力和速度以及冷却孔的分布等对转子温度场的以及散热效率的影响,优化散热路径,完成高功率半导体整流管芯片散热计算。实验结果表明,所提方法有效减少了计算时间,提高了计算效率,与此同时,降低了计算误差,使计算结果更为准确。     

电动汽车轮毂电机散热规律

采用计算流体力学方法对电动汽车轮毂电机的散热规律进行数值仿真计算,得到整车流场下各电机的表面温度、表面传热系数,各车轮的空气质量流等参数的分布及变化规律。结果表明：前轮电机受前端散热模块影响较大;右前轮电机外壳温度高于左前轮电机和后轮电机;前轮电机表面传热系数明显大于后轮。随着车速的增加,产生较多的冷却气体,电机表面散热情况有所好转。     

Development of modularized airtight controller for mobile welding robot working in harsh environments

This paper proposes the design and validation of a new hermetic controller for mobile robots working in a hazardous environment. Two years ago, we obtained very successful results with regard to the development of the new mobile robot RRX, which can weld, blast, and paint double-hulled structures during the shipbuilding process. At that time, some attempts were made to design a modular and hermetic controller to secure a robust cooling performance and dustproof quality because the temperature is 40–50 °C during the summer, and such operations produce considerable amounts of metallic dust such as fumes. This naturally represents a very hazardous environment for the robot's controller, for which the temperature should be maintained at its rated level, and the body should be kept fully airtight to prevent the inflow of metallic dust. Thus, in that research, heat pipes were successfully adopted to satisfy these design constraints by dissipating the heat from the servomotor drivers and several power units without any airflow into the controller for cooling. The proposed cooling system is composed of heat pipes, cooling fins, fans, and L-shaped brackets for transferring the produced heat from the heating resources to the heat pipes. Experiments were performed in the field to obtain information on the motor driver's heating value and work site temperatures as boundary conditions of the heat transfer problem, and a modular and hermetic controller for mobile robots working in hazardous environments was successfully developed and validated. The obtained experimental results fully support the idea that this design is appropriate for the controller to maintain a stable performance in a harsh environment.     

计算机CPU芯片散热技术研究

在对计算机CPU散热技术研究的重要作用进行分析的基础上,探讨了当前计算机CPU芯片风冷散热技术及其特点。最后,结合具体的设计实例,采用温度数值模拟软件对之进行了模拟分析,得到了CPU芯片散热器性能随着其结构尺寸变化的规律,为提高CPU散热性能起到一定的参考。     

Deviation-tolerant floating gate structures as a way to design an on-chip learning neural networks

 Hardware implementation of artificial neural networks (ANN) based on MOS transistors with floating gate (Neuron MOS or νMOS) is discussed. Choosing analog approach as a weight storage rather than digital improves learning accuracy, minimizes chip area and power dissipation. However, since weight value can be represented by any voltage in the range of supplied voltage (e.g. from 0 to 3.3 V), minimum difference of two values is very small, especially in the case of using neuron with large sum of weights. This implies that ANN using analog hardware approach is weak against V _dd deviation. The purpose of this paper is to investigate main parts of analog ANN circuits (synapse and neuron) that can compensate all kinds of deviation and to develop their design methodologies.     

Novel heat dissipation design for light emitting diode applications

The authors offer a new design in support of efficient heat dissipation for light emitting diodes (LEDs). In the first part of this paper we discuss improvements in LED packaging materials and layer assembly, and then describe the addition of a thin layer of electroplated copper to the LED base assembly to reduce thermal resistance and increase thermal diffusion efficiency. Also described is a three-dimensional finite element simulation that we performed to verify the proposed design (0.75, 1, and 3 W LED chip temperatures) and a LED heat transfer behavior analysis. The results indicate that the addition of a 9 mm² electroplated copper layer to the LED base assembly improved LED thermal dissipation by reducing chip temperature by 5°C compared to LEDs without the copper layer packaging. In the second part of this paper we describe (a) our heat pipe system/heat sink design for LED illumination, and (b) experiments in which we changed both working fluid mass and rotation angle to determine their effects on heat pipe cooling. Our results indicate that the most efficient heat dissipation occurred when an added heat pipe was arranged horizontally. Good heat dissipation was observed for heat pipes containing 2.52 g of water (temperature reduced by 50°C). Larger water volumes failed to dissipate additional heat due to the presence of steam inside the pipe.