摘要
散热片是保障电力电子器件在正常温度下工作的一个必不可少的部件 ,而散热片与电力电子器件间的电容耦合是电力电子装置产生共模辐射的主要原因之一 ,其对研究电力电子装置的辐射发射特别重要。本文首次采用 FDTD法计算了散热片和电力电子器件间的高频耦合电容 ,重点研究了置于电力电子器件与散热片之间的屏蔽层对耦合电容时频特性的影响。计算结果表明 :高频端 ,散热片和电力电子器件的尺寸与所关心的波长相比拟 ,分布参数影响了该电容的数值。该耦合电容已经不能看作简单常数 ,而是一个随时间、频率变化的量。对本文设计的模型 ,加有屏蔽层时 ,耦合电容减小。结论说明 ,不能用静电场推导的电容公式简单计算频率很高时的耦合电容 ,也可以这么说 ,某些低频时建立的概念解释不了频率很高时的物理现象。
Heatsink is an indispensable component in power electronic system. However, coupling capacitance between the heatsink and power electronic devices produces common-mode emission in power electronic equipment, which is very important for studying radiation emission. In this paper, coupling capacitance between the heatsink and power electronic devices and shielding effect are studied by FDTD method. It is shown that in high frequency, size of the heatsink and devices is approximate to wavelength, the value of the capacitance is influenced by distributed parameters. Coupling capacitance cannot be considered as a constant, but a function of time and frequency. Coupling capacitance become smaller after shielding. Couple capacitance in high frequency cannot be calculated simply by static-electric field capacitance equation. It means that high frequency physical phenomenon cannot be comprehended using concept which is created in low frequency.
出处
《铁道学报》
EI
CAS
CSCD
北大核心
2001年第6期59-62,共4页
Journal of the China Railway Society
