Design of Planar transformer

《Design of Planar transformer》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、DesignofPlanarPowerTransformersContentsIntroduction3Designprocedure4Designexamples-flyback8-forward10Formulas13Layerdesign141FerroxcubeExplodedviewofaplanartransformer2FerroxcubeIntroductionPlanartransformerscanbeconstructedasstandalonecomponents,withastackedlay

2、erdesignorasmallmultilayerPCB,orintegratedintoamultilayerboardofthe1/2planarEcorepowersupply.Importantadvantagesofplanarmagneticsare:layer1-verylowprofile-excellentthermalcharacteristics.layer2-lowleakageinductance-excellentrepeatabilityofpropertiesmultilayerPCB

3、layer3MeasurementsonplanarEcoretransformersunderlayer4operatingconditionswithwindingsinmultilayerPCBsshowthatthethermalresistanceissubstantiallylower(upto50%)comparedtoconventionalwirewoundtransformerswiththesameeffectivecorevolumeVe.1/2planarECoreThisiscausedby

4、theimprovedsurfacetovolumeratio.standalonetransformerTheresultofthisbettercoolingcapabilityisthatplanartransformerscanhandlehigherthroughputpowerdensities,whilethetemperatureriseisstillwithinacceptablelimits.Thisbrochurepresentsafastandeasymethodtomakedesignsfor

5、planarpowertransformers.Exampleswhichhavebeendesignedwiththisfastprocedurewillbediscussed.Testsunderoperatingconditionsshowthatthemeasuredresultsareingoodagreementwiththepredictedtemperaturerise.integratedintoPCBPlanarprinciples3FerroxcubeDesignprocedure1.Calcul

6、ationofmaximumfluxdensityThecoreandcopperlossesinatransformerunderPowerlossesinourferriteshavebeenmeasuredasaoperatingconditionswillinduceatemperaturerise.functionoffrequency(finHz),peakfluxdensity(BinThisrisemuststaybelowamaximumallowablevaluetoT)andtemperature

7、(Tin°C).Corelossdensitycanbeavoiddamagetothetransformerortherestofthecircuitry.approximated(2)bythefollowingformula:Inthermalequilibriumthetotallossesinthetransformer,Pcore=Cm.fx.By.(ct0-ct1T+ct2T2)[3]Ppeaktrafo,canberelatedtoatemperatureriseDTofthetransformerwi

8、thananalogonofOhm’slawby:xy3=Cm.CT.f.Bpeak[mW/cm]DTPtrafo=[1]RthInthisformulaCm,x,y,ct0,ct1andct2areparameterswhichhavebeenfoundbycurvefittingofthemeasuredInthisformu