发动机电控系统ECU系统散热优化设计研究

论文总字数：46762字

摘 要

为了满足节能减排、智能安全的社会需求，顺应集成化、模块化的电子技术发展趋势，汽车电控单元ECU的功能越发复杂，体积不断缩小，整体热密度随之增加，散热问题日益严峻。本文基于有限元算法，使用计算流体动力学CFD，研究了汽车电控单元ECU的散热性能优化。

元件级仿真方面，介绍了几种常见封装，建立了LQFP和BGA的详细模型，并在20℃的JEDEC标准板上，进行了符合JESD51标准的结到环境和结到印制板的热阻测试。文章比较了IC封装的三种建模方式，结果表明，同详细模型、双热阻模型相比，DLPHI模型误差满足要求且解算效率高。板级仿真方面，分析了热过孔特性对散热的影响，得出结论，增加热过孔数目、提升塞孔率、加大内层孔径和间距之比超过0.2、加大镀铜厚度和间距之比超过0.02，可以有效提高板厚方向导热系数，降低模型温度。同时，建立了车辆控制器MCU的详细模型和简化模型，施加多种网格划分方式，观察元件随网格数变化情况，讨论了收敛方法，进行了网格独立性检验，找到了满足精度要求的合适划分方式。

最后，用热过孔对简化模型进行优化，平均降温0.5℃。用实验设计DOE方法对板结构进行优化，给出了的ECU热模型精度优化建议

关键词：ECU热仿真，封装，热过孔，网格划分，FloTHERM

Abstract

In order to meet the social demand of energy conservation, emission reduction and intelligent safety, and to comply with the development trend of integrated and modular electronic technology, ECU of automobile has more and more complex functions, and its volume is decreasing, and the overall thermal density is increasing with it, and the heat dissipation problem is becoming increasingly serious. Based on finite element method and CFD, this paper studies the optimization of heat dissipation performance of ECU.

In the aspect of component level simulation, several common packages are introduced, the detailed models of LQFP and BGA are established, and the thermal resistance tests of junction to environment and junction to PCB in line with JESD51 standard board are carried out on JEDEC standard board at 20℃. This paper compares three modeling methods of IC package, and the results show that the DLPHI model error meets the requirements and the solution efficiency is high compared with the detailed model and the dual thermal resistance model. In the aspect of plate-level simulation, the influence of hot-through-hole characteristics on heat dissipation was analyzed, and the conclusion was drawn that increasing the number of hot-through-hole, increasing the rate of plug hole, increasing the ratio of inner layer aperture and spacing to more than 0.2, and increasing the ratio of copper plating thickness and spacing to more than 0.02 could effectively improve the thermal conductivity of plate thickness direction and reduce the model temperature. At the same time, the detailed model and simplified model of MCU of vehicle controller are established, various grid division modes are applied, the variation of elements with grid number is observed, the convergence method is discussed, the grid independence test is carried out, and the appropriate division mode satisfying the precision requirement is found.

Finally, the simplified model was optimized by means of hot through hole, with an average temperature drop of 0.5℃. The experimental design DOE method is used to optimize the plate structure

KEY WORDS: ECU thermal simulation, packaging, thermal via, meshing, FloTHERM

目 录

摘 要 3

Abstract 4

第一章 绪论 1

1.1选题的背景与意义 1

1.3国内外研究现状和趋势 2

1.3.1通用电子设备热设计 2

1.3.2车用电控系统ECU的热设计 3

1.4本文主要研究内容 8

1.5本文组织结构 8

第二章 ECU热性能分析 9

2.1需解决的关键性问题分析 9

2.2传热学基础 9

2.3 ECU热流通路 10

2.4 ECU良好散热的重要性 10

2.5 ECU热模型建模过程 11

2.6板级ECU仿真和实验所得的差异 14

2.7本章小结 15

第三章 封装对ECU散热的影响 16

3.1典型芯片封装 17

3.2 LQFP详细模型 18

3.2.1封装建模 18

3.2.2结到环境热阻 19

3.2.3温度监控点位置的影响 20

3.2.4封装结点到PCB热阻 21

3.3 TBGA详细模型 22

3.3.1封装建模 22

3.3.2结到环境热阻 23

3.3.3结到PCB板热阻 24

3.4详细模型、双热阻、DLPHI热阻网络模型差异 24

3.5本章小结 26

第四章 热过孔对ECU散热性能影响 27

4.1热过孔数目对散热的影响 27

4.2热过孔特性指标对散热的影响 30

4.2.1理论学习 30

4.2.2实验验证 31

4.3本章小结 33

第五章 ECU电路板设计 34

5.1板级建模简述 34

5.2不同模块网格划分要点 35

5.2.1常用设置参数 35

5.2.2常用划分方式 36

5.3改善收敛手段 36

5.4网格独立性检验 37

5.5对比电控单元详细模型和简化模型 38

5.5.1详细模型 38

5.5.2简化模型 43

5.5.3对比与分析 48

5.6基于热过孔的简化模型优化 48

5.7基于DOE方法的电路板构造优化 49

5.8本章小结 50

第六章 总结和展望 52

6.1全文总结 52

6.2研究展望 52

参考文献 53

致 谢 56

1. 绪论

1.1选题的背景与意义

随着物质生活的极大丰富和交通运输业的飞速发展，汽车成为人们日常生活中不可或缺的一部分。日殊月异的现代电子技术与汽车产业相互交织，推动了汽车使用效能和元件工作性能的提高，使汽车从单一的机械装置过渡到机电一体化产品。汽车电控单元ECU作为汽车电子技术的核心，在新能源混合动力汽车和自动驾驶的研发热潮中发挥着不可替代的作用，承担着时代对于汽车节能、安全和高性能的追求，为汽车电子技术的不断进步提供了动力和方向，助力了能源与环境的可持续发展[1][2]。

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