功率器件的散热计算及散热器选择

目前的电子产品主要采用贴片式封装器件,但大功率器件及一些功率模块仍然有不少用穿孔式封装,这主要是可方便地安装在散热器上,便于散热。进行大功率器件及功率模块的散热计算,其目的是在确定的散热条件下选择合适的散热器,以保证器件或模块安全、可靠地工作。     

功率器件热设计及散热计算

在模拟电路设计过程中难免会使用功率器件,如何处理和解决这些功率器件散热问题对于设计师来说非常重要,因为这些功率器件的工作温度将直接影响到整个电路的工作稳定性和安全性,文中介绍了功率器件的热性能参数,并根据作者的实际工作经验,阐述了功率器件的热设计方法和散热器的合理选择。     

功率型LED散热器的研究

分析了目前功率型LED发展存在的瓶颈问题,以及散热对LED器件正常工作的重要性.散热器的设计决定了功率型LED芯片产生的热量能否顺利传至工作环境,基于现有的文献和专利总结了大功率LED散热器的技术手段及其研究内容.从对流散热、辐射散热、热传导和相变散热等多个方面介绍了一些典型散热器在功率型LED散热中的应用,并提出了未来LED照明散热设计的方向.     

MOSFET功率开关器件的散热计算

文中介绍了以MOSFET为代表的功率开关器件功率损耗的组成及其计算方法，给出了功率器件散热器的热阻计算方法和步骤．简要说明了在采用风冷散热时应遵循的一般准则。     

功率变换器肋片散热器的理论分析与优化设计

针对现有散热器模型的不足,建立了恒热流的边界条件下的散热器的数学模型,得到了散热器的温度分布公式。提出了散热器的优化方法,并利用Flux软件对现有功率变换器的散热器在自然空气冷却条件下进行优化。得到了两种优化方案,都在功率器件允许的温度范围内减小散热器的体积和质量,从而充分发挥了散热器的作用。     

半导体功率器件散热系统的设计

本文分析了功率器件散热系统的设计方法,对比了叉指式与肋式散热器的优缺点,讨论了计算中遇到的具体问题;和散热器的选用要点及散热系统的结构工艺问题。     

PCB板级电路中高效散热结构的优化设计

印制电路板(PCB)厚度方向的导热系数比平面方向的导热系数小得多,为了改善板厚度方向的导热性能,提出了一种改进的自然对流冷却散热方式。首先,通过在PCB板中设计热过孔并在其背面安装散热器,应用热分析软件Icepak对散热模型进行仿真,优化设计散热器翅片的厚度和数目对功率器件温度分布的影响;然后,根据优化后的结果,选定最佳修正尺寸,制作测试结构;最后,采用热电偶法对其进行实验测试,结果表明此散热结构可有效降低器件的温度。     

某功率单元强迫风冷散热分析和优化

随着电子技术的发展,电子设备的散热问题显得越来越重要。以理论分析的基础上,针对某功率单元整体温度场和速度场,采用有限元的方法,进行数值分析。重点分析不同风机、不同翅片散热器下,功率单元温度场和流场的分布趋势。得到采用引风机、翅片较密的散热器(62个翅片),能够达到最佳的散热效果,满足实际工程需要,有利于功率单元长期可靠运行。     

CPU风冷散热器散热性能的实验测试

CPU风冷散热器作为最传统的散热方式,现在仍被广大PC机用户使用.按散热片材料分为全铝、全铜和铜铝复合式三种,其中铜铝复合式是现今主流产品.为对其散热性能进行测试,设计测试散热器散热性能的实验装置.通过改变输入电压,改变风道、风速和模拟芯片的发热功率,测试目前PC机使用最多的放射状铜铝复合式风冷散热器在不同风速、不同加热功率下强迫风冷时的散热性能.从它的瞬时储热能力、热阻及CPU表面温度三个方面分析其散热性能,得出这款散热器能较好地满足CPU发热功率在120 W以内的散热需求.实验测试装置具有通用性,实验结果有助于对此款散热器的改进,以提高其散热性能.     

大功率电子器件散热系统的数值模拟

针对大功率器件的散热状况,采用强迫水冷的散热系统设计方案,并依据国家有关标准与试验要求,应用有限元分析软件ANSYS对其水冷散热器的流场、温度场进行了数值模拟和系统分析.模拟结果不仅可以方便地观察到散热器内腔各处水流的饱和程度、流速及压力分布,而且可以得到功率器件、散热器和流体的温度分布;同时也验证了数值模拟方法的合理性,对散热器结构的优化设计提供了可靠的保证.     

固体激光器中多块热沉夹持晶体散热时接触热导研究

采用圆棒状工作物质的固体激光器中,通常用2块带有半圆型凹槽的金属热沉夹持晶体散热。装配压强在晶体与热沉接触面上的不均匀分布,造成二者间接触热导沿圆周变化,在晶体中产生非轴对称的温度分布。提出采用3块或4块热沉夹持圆棒晶体散热,利用截断高斯模型和塑性形变模型计算晶体与热沉间接触热导,建立了接触散热模型,并用有限元法得到晶体温度分布。结果表明,2块热沉夹持圆棒晶体散热时,晶体侧面压强、接触热导沿圆周变化明显,在热沉凹槽底部达到最大,在2块热沉结合面处为零,晶体端面温度沿周向变化较大。采用3块热沉时,晶体侧面压强、接触热导及温度分布的周向均匀性提高,端面中心温度降低,采用4块热沉时,晶体侧面压强、接触热导及温度分布的周向均匀性最好,端面中心温度最低。     

Parametric optimization of multichanneled heat sinks for VLSI chipcooling

This paper presents an optimization study of multichannel heat sinks for electronic devices. Specifically, we present a method of determining optimum values of the channel diameter, flow rate and number of channels for minimum pumping power or minimum pressure drop. Optimized parameters are expressed in dimensionless form. The calculated results for both laminar and turbulent regimes present several important relationships among the parameters. A criterion for choice of the flow regime to be used is presented. For a current electronic cooling requirement, the optimized diameter of a channel lies in the micro-scale range when water is used as working fluid. Several advantages of an optimized heat sink and its' feasibility toward actual cooling problems are discussed     

Heat transfer and residual stress modeling of a diamond film heat sink for high power laser diodes

A three-dimensional finite element model of heat transfer and residual stress within high power laser diodes and their heat sinks is developed. These components are typically used in telecommunication applications. The model addresses both p-side down and p-side up laser diodes mounted on a variety of commercially available gold plated diamond heat sinks. In addition, the model is optimized with respect to the dimensions of the diamond film, and the laser diode cavity lengths. Finally, the design and performance of diamond film heat sinks for high performance GaAs and InP laser diodes are discussed. The results demonstrate the superior performance achieved through thermal engineering of the dominant thermal transport path from the laser diode heat source through diamond films to the heat sink.     

Geometrical Design of Plate-Fin Heat Sinks Using Hybridization of MOEA and RSM

The work in this paper is aimed at demonstrating the practical multiobjective optimization of plate-fin heat sinks and the superiority of using a combined response surface method and multiobjective evolutionary optimizer over solely using the evolutionary optimizer. The design problem assigned is to minimize a heat sink junction temperature and fan pumping power. Design variables determine a heat sink geometry and inlet air velocity. Design constraints are given in such a way that the maximum and minimum fin heights are properly limited. Function evaluation is carried out by using finite volume analysis software. Two multiobjective evolutionary optimization strategies, real-code strength Pareto evolutionary algorithm with and without the use of a response surface technique, are implemented to explore the Pareto optimal front. The optimum results obtained from both design approaches are compared and discussed. It is illustrated that the multiobjective evolutionary technique is a powerful tool for the multiobjective design of electronic air-cooled heat sinks. With the same design conditions and an equal number of function evaluations, the multiobjective optimizer in association with the response surface technique totally outperforms the other. The design parameters affecting the diversity of the Pareto front include fin thickness, fin height distribution, and inlet air velocity while the plate base thickness and the total number of fins of the non-dominated solutions tend to approach certain values.     

On-Chip Thermal Management With Microchannel Heat Sinks and Integrated Micropumps

Liquid-cooled microchannel heat sinks are regarded as being amongst the most effective solutions for handling high levels of heat dissipation in space-constrained electronics. However, obstacles to their successful incorporation into products have included their high pumping requirements and the limits on available space which precludes the use of conventional pumps. Moreover, the transport characteristics of microchannels can be different from macroscale channels because of different scaling of various forces affecting flow and heat transfer. The inherent potential of microchannel heat sinks, coupled with the gaps in understanding of relevant transport phenomena and difficulties in implementation, have guided significant research efforts towards the investigation of flow and heat transfer in microchannels and the development of microscale pumping technologies and novel diagnostics. In this paper, the potential and capabilities of microchannel heat sinks and micropumps are discussed. Their working principle, the state of the art, and unresolved issues are reviewed. Novel approaches for flow field measurement and for integrated micropumping are presented. Future developments necessary for wider incorporation of microchannel heat sinks and integrated micropumps in practical cooling solutions are outlined.     

电子产品散热器的设计

对电子产品使用的散热器的散热原理、主要影响因素进行了分析,建立了数理模型,并对如何选择散热器提供了一些可行的依据.     

Thermal analysis of LED lighting system with different fin heat sinks

This paper designs a 3×3 light emitting diode(LED) array with a total power of 9 W,presents a thermal analysis of plate fin,in-line and staggered pin fin heat sinks for a high power LED lighting system,and develops a 3D one-fourth finite element(FE) model to predict the system temperature distribution.Three kinds of heat sinks are compared under the same conditions.It is found that LED chip junction temperature is 48.978℃when the fins of heat sink are aligned alternately.     

Least-energy optimization of air-cooled heat sinks for sustainable development

The development of heat sinks for microelectronic applications, which are compatible with sustainable development, involves the achievement of a subtle balance between a superior thermal design, minimum material consumption, and minimum pumping power. This presentation explores the potential for the least-energy optimization of natural and forced convection cooled rectangular plate heat sinks. The results are evaluated in terms of a heat sink coefficient of performance, relating the cooling capability to the energy invested in the fabrication and operation of the heat sink, and compared to the entropy generation minimization methodology (EGM).     

Geometric optimization of a micro heat sink with liquid flow

Over the course of the past decade, a number of investigations have been conducted to better understand the fluid flow and heat transfer in microchannel heat sinks, particularly as it pertains to applications involving the thermal control of electronic devices. In the current investigation, a detailed numerical simulation of the heat transfer occurring in silicon-based microchannel heat sinks has been conducted in order to optimize the geometric structure using a simplified, three-dimensional (3-D) conjugate heat transfer model [two-dimensional (2-D) fluid flow and 3-D heat transfer]. The micro heat sink modeled in this investigation consists of a 10 mm long silicon substrate with rectangular microchannels fabricated with different geometries. The rectangular microchannels had widths ranging from 20 /spl mu/m to 220 /spl mu/m and a depth ranging from 100 /spl mu/m to 400 /spl mu/m. The effect of the microchannel geometry on the temperature distribution in the microchannel heat sink is presented and discussed assuming a constant pumping power. The model was validated by comparing the predicted results with previously published experimental results and theoretical analyses, and indicated that both the physical geometry of the microchannel and the thermophysical properties of the substrate are important parameters in the design and optimization of these microchannel heat sinks. For the silicon-water micro heat sink, the optimal configuration for rectangular channel heat sinks occurred when the number of channels approached 120 channels per centimeter.