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1、NovelTechniquestoCancelCommon-modeNoiseBasedonNoiseBalance基于噪声平衡的抵消共模干扰新技术Abstract:概要:Roleofwindingshieldingontheparasiticcapacitancesoftransformerandcommon-mode(CM)noiseisanalyzedindetailswhenconsideringtheeffectsofthesecondarysidenoisesource・BasedontheproposedmodelofCMnoise,twonove
2、ltechniquestocancelCMnoisebybalancingnoiseisgiven;experimentresultsshowCMnoiseisgreatlyreducedwhenthetechniquesareadopted・详细分析线圈屏蔽对变压器寄生电容和共模(CM)噪声的影响。基于共模噪声模型,俩平衡噪声的新技术用来抵消共模噪声;实验证明共模噪声被显著降低当技术被应用时。I•Introduction一.导言AswitchingpowerconvertergenerateslargerCMnoiseasaresultoftheswitchi
3、ngoperationsinthepreseneeofparasiticcapacitaneebetweenwindingsoftransformer.Inordertoreducecommon-modeEMIemission,aFaradayshieldingbetweentheprimaryandsecondarywindingsofthetransformerisoftenadoptedinpracticetoreducetheeffectivecouplingcapacitancebetweenthewindings.Someresearchesonth
4、emodelingofthestraycapacitiveeffectsinthetransformerwerereported[1,2,3].However,theyusuallydidnotconsidertheeffectsoftheshieldingandwerenotgoodenoughforEMIanalysisinpracticaldesign.变压器绕组间存在技术电容因而开关电源运行时会产生大量的共模噪声。为减少共模电磁干扰发射,通常在变压器初次级绕组间加入法拉第屏蔽来减少绕组间的电容耦合。一些研究这些杂散电容的报告见参考文献[1,2,3]。但是
5、,通常的屏蔽做法在实际设计中对电磁干扰分析来说并不够好。Typically,CMnoisemakesupasignificantfractionofelectromagneticinterference(EMI),solargesizeofCMchokeisneededifwewanttosuppressEMInoiseintheinputline・InordertoreducethesizeofEMIfilterandcost,noisecancellationtechniqueshavebeenintroducedtotheareaofEMIinresent
6、years[4][5],Thosetechniqueshavethedisadvantagesofcomplexityandneedadditionalcomponents.Inthispaper,roleofwindingshieldingonparasiticcapacikinceoftransformerandCMnoisewhentakingintoaccounttheeffectsofthesecondarysidenoisesourceisanalyzedindetails;basedonmodelofCMnoise,twonoveltechniqu
7、estocancelCMnoisebybalancingnoisearegiven,Itissimplerorlesscostcomparedwithprevioustechniques,thetechniquescanbeappliedtoisolatedconverters,suchasFly-backconverter,Forwardconverter,etc.Inthelastsectionofthepaper,effectofthemethodonCMnoisereductionisverifiedbyexperiments.共模噪声是构成电磁干扰的典
8、型的一部分,为抑制电磁干