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术语及定义Terms&Definitions1.起始磁导率Initialpermeability,μi起始磁导率是磁性材料的磁导率(B/H)在磁化曲线初始区的极限值,即ThisisthelimitvalueofB/HwhereHisindefinitelyclosetozeroattheinitialmagnetizationcurveofaferromagneticsubstance.式中Where:μ0为真空磁导率permeabilityinvacuum(4π×10-7H/m)H为磁场强度magneticfieldstrength(A/m)B为磁通密度magneticfluxdensity(T)2.有效磁导率Effectivepermeability,μe为了便于绕线,在变压器和电感器中常用两只磁心配对构成闭合磁路。由于磁路各部分形状尺寸不同,且配合面又残存气隙(为改善性能,有时在磁路中开制气隙),因此要用有效磁导率代替起始磁导率来表示磁心的性能。在闭合磁路中Thisisusuallydefinedastheeffectivepermeabilityofacoreformingaclosedcircuitwhereleakagefluxisnegligiblysmall.式中Where:L为装有磁心的线圈的电感量self-inductanceofcoilwithcore(H)N为线圈匝数numberofcoilturnsLe为磁心有效磁路长度effectivemagneticpathlengthofcore(m)Ae为磁心有效截面积effectivecross-sectionalareaofcore(m2)3.饱和磁通密度Saturationfluxdensity,Bs(T)材料磁化到饱和状态的磁通密度。见图1Saturationfluxdensityisthemaximumattainablefluxdensitywhenaveryhighmagneticfieldisappliedtoasoftmagneticmaterial,asshowninFig.14.剩余磁通密度Residualmagneticfluxdensity,Br(T)从饱和状态去除磁化场后,剩余的磁通密度。见图1Thisistheamountofresidualmagneticfluxdensityretainedbythecoreafterthemagneticfieldisweakenedandfinallyremoved,asshowninFig1.5.矫顽力Coercivity,Hc(A/m)从饱和状态去除磁场后,磁心继续被反向的磁场磁化,直至磁通密度减为零,此时的磁场强度称为矫顽力。见图1Thisisthestrengthofthemagneticfieldwherebytheresidualfluxdensitybecomeszeroundertheintensificationintheoppositedirectionofthemagneticfield,asshowninFig1.6.损耗因数Lossfactor,tanδ损耗因数是磁滞损耗、涡流损耗和剩余损耗三者之和:Thelossfactorcanbesplitupintothreeparts:tanδ=tanδh+tanδe+tanδr式中Where:tanδh为磁滞损耗hysteresislossTanδe为涡流损耗eddy-currentlossTanδr为剩余损耗residualloss7.相对损耗因数Relativelossfactor,tanδ/μ相对损耗因数是损耗因数与磁导率之比。tanδ/μi适用于材料;tanδ/μe适用于磁路中含有气隙的磁心。Thisistheamountoflossperunitpermeabilityandisexpressedasfollows:tanδ/μi(formagneticmaterial)tanδ/μe(wheregapsareaddedtothemagneticcircuit)8.磁滞常数Hysteresismaterialconstant,ηB(10-6/mT)磁滞常数表征材料在磁通密度增加时磁滞损耗的变化Hysteresismaterialconstantcharacterizesthechangeofthehysteresislossofthematerialwhenthefluxdensityisincreased.式中Where:tanδ为损耗因数lossfactorμe为有效磁导率effectivepermeabilit