开关电源EMI与热设计全面集成方法

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本篇文档"开关电源完整的EMI和热设计"详细探讨了在开关电源设计中至关重要的电磁兼容（EMI）和热管理问题。作者Wei Zhang在这份硕士论文中提交给弗吉尼亚理工大学，旨在满足电气工程硕士学位的要求。论文的核心内容涵盖了如何通过计算机辅助设计（CAD）工具进行EMI性能建模和分析，以及热性能的集成设计。论文首先介绍了一种方法论，即开发了一套针对开关电源的EMI和热设计指南。通过以Boost PFC电路为例，作者构建了一个EMI噪声抑制的等效电路模型，这有助于理解和优化电源在工作中的电磁干扰水平。这样的模型对于确保电源设备在满足功能需求的同时，符合严格的电磁兼容标准至关重要。在热设计部分，论文深入研究了开关电源内部组件的热行为，包括功率模块、散热器和控制器的温度管理。作者探讨了热传导、对流和辐射等各种散热机制，以及如何通过有效的热路径设计来降低开关电源的温升，从而提高其效率并延长使用寿命。这不仅涉及硬件的选择和布局，还涉及到材料属性、冷却介质和散热器的设计优化。此外，论文可能还讨论了使用CAD工具进行热仿真，以预测不同负载和工作条件下的温度分布，以便进行早期的故障预防和性能优化。同时，论文可能会提到相关的国际标准，如IEC 61000系列标准，这些标准对于开关电源产品的EMI和热设计有着严格的规范。这篇论文提供了宝贵的实践指导，对于从事开关电源设计的专业人员来说，学习如何在设计过程中兼顾EMI和热管理，提升电源产品的质量和可靠性具有很高的参考价值。通过阅读和应用其中的方法和技术，工程师们可以更好地控制电源系统的性能，减少环境影响，并满足日益严格的法规要求。

Introduction

CHAPTER 1

NTRODUCTION

1.1. Background and Motivation

In recent years, many of the design issues of a power supply have been

intensively addressed. Issues such as power stage topology, control modeling,

performance analysis, soft-switching topologies, and magnetic component optimization.

However, two major issues, EMI control and thermal management have been far from

adequately addressed. Cut and trial method is normally used to solve these problems.

Switch-mode power supplies generate high frequency noises because of their

switching action. In the continuous effort to increase converter power density, switching

frequency is becoming higher which, in general, makes EMI performance worse. The

generated noises from the power stage may cause malfunction of control circuitry within

the converter itself, as well as electromagnetic compatibility (EMC) problems to the

surrounding equipment. EMI noises need to be controlled and minimized. A variety of

EMC standards regulates conducted and radiated emission and have become more

stringent in recent years.

The failure probability of electronic components depends primarily on the

operating temperature. According to statistics of the U.S. military department, thermal

overstressing is the cause for most of the failures in modern electronic systems [25]. To

ensure proper operation, the maximum allowable temperature is usually determined for

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Introduction

the semiconductor device and magnetic components. In the continuous effort to decrease

the volume of power converters, the switching frequency is becoming higher, and the

power density of converters is higher. The increasing use of surface-mount technology,

avoidance of fans to reduce noise and volume, and reduced package dimensions all

intensify the thermal design requirement.

At the present time, the design practice in power supply industry is that both EMI

and thermal requirements are tested at the final hardware implementation stage. A long

redesign time is normally necessary if corrections are needed. A more efficient way to

deal with these two issues is to tackle them in the design process, before the hardware

implementation is done. It’s the primary objective of this thesis to develop a methodology

to deal with the issues and demonstrate the feasibility in a practical power circuit. With

these tools, not only design time can be greatly reduced but also extrapolation of

performance can be easily made for design optimization.

1.2. Approach

The approach used in this thesis is based on four existing simulation tools, the

InCa, a parasitic parameter extracting software, the Ansoft, a Maxwell electromagnetic

field simulation and parameter extraction tool, the Saber, a circuit simulation tool, and

the Flotherm, a thermal analysis tool. These will be discussed in the following.

Conducted EMI simulation

Parasitic elements play major roles in the EMI performance of a power supply.

Therefore, all the essential parasitic elements of the power circuit and the printed circuit

board must be included to perform EMI simulation. For the discrete components such as

MOSFETs and diodes, the parasitic elements can be found from the product manual. For

the input and output capacitors, the parasitic elements can be measured by an Impedance

Analyzer. The parasitic elements of magnetic component can be analytically calculated or

practically measured. And the software InCa is used to extract the layout parasitic

elements and generate an equivalent circuit. Both the power circuit and the layout

equivalent circuit are then connected for EMI performance simulation. Software Saber is

then used to simulate the circuit.

Thermal simulation

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开关电源EMI与热设计全面集成方法

参考资料-开关电源完整的EMI和热设计 y.zip

《开关电源设计》csdn

陈永真开关电源书pdf文档

ti电源设计基础 pdf

硬开关和软开关的区别

DCDC buck开关频率

如何设计MOS驱动电路

MOS管和IGBT斩波频率设置

fundamentals of power electronics 高清 pdf

drv8311 电路设计

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