xov xwm

Hauv peb lub ntiaj teb zoo tagnrho, kev nyab xeeb, kev ua tau zoo thiab kev ua haujlwm yog qhov tseem ceeb.Txawm li cas los xij, tus nqi ntawm cov khoom kawg, suav nrog cov ferrite, tau dhau los ua qhov kev txiav txim siab.Qhov tsab xov xwm no yog tsim los pab tsim engineers nrhiav lwm cov ntaub ntawv ferrite los txo. nqi.
Cov khoom siv hauv tsev uas xav tau thiab cov tub ntxhais geometry yog txiav txim siab los ntawm txhua daim ntawv thov tshwj xeeb.Inherent cov khoom uas tswj kev ua haujlwm hauv cov teeb liab qis qis yog permeability (tshwj xeeb tshaj yog kub), tsis tshua muaj tub ntxhais poob, thiab zoo sib nqus ruaj khov nyob rau lub sijhawm thiab kub.Cov ntawv thov suav nrog high-Q inductors, hom hom inductors, broadband, matched thiab mem tes transformers, xov tooj cua kav hlau txais xov hais, thiab nquag thiab passive repeaters.Rau cov kev siv fais fab, siab flux ceev thiab tsawg poob ntawm kev khiav hauj lwm zaus thiab kub yog cov yam ntxwv xav tau.Cov ntaub ntawv muaj xws li hloov hom fais fab khoom siv rau electric tsheb roj teeb them, sib nqus amplifiers, DC-DC converters, lub hwj chim lim, ignition coils, thiab transformers.
Cov cuab yeej tseem ceeb uas muaj qhov cuam tshuam loj tshaj plaws ntawm kev ua tau zoo ntawm ferrite hauv kev siv tshuaj tua kab mob yog qhov nyuaj permeability [1], uas yog proportional rau lub impedance ntawm cov tub ntxhais.Nws muaj peb txoj hauv kev siv ferrite ua ib qho kev tawm tsam ntawm cov cim tsis xav tau (ua los yog tawg. ) Thawj, thiab tsawg tshaj plaws, yog raws li cov ntaub thaiv npog, qhov twg ferrites siv los cais cov conductors, Cheebtsam los yog circuits los ntawm cov radiating stray electromagnetic teb ib puag ncig.Hauv daim ntawv thov thib ob, ferrites yog siv nrog cov ntsiab lus capacitive los tsim kom muaj qhov tsawg dhau. lim, piv txwv li inductance - capacitive ntawm tsawg zaus thiab dissipation ntawm high frequencies.Qhov thib peb thiab feem ntau siv yog thaum ferrite cores yog siv ib leeg rau kev tivthaiv coj los yog pawg thawj coj saib-theem circuits.Hauv daim ntawv thov no, ferrite core tiv thaiv cov kab mob parasitic oscillations thiab/ los yog attenuates tsis xav tau lub teeb liab los yog kis tau tus mob uas yuav propagate raws cov tivthaiv coj los yog interconnects, kab los yog cables.Nyob rau hauv lub thib ob thiab thib peb daim ntawv thov, ferrite cores suppressed EMI los ntawm kev tshem tawm los yog zoo heev txo cov zaus tam sim no los ntawm EMI qhov chaw.Qhov kev qhia ntawm ferrite muab Nyob rau hauv txoj kev xav, qhov zoo tshaj plaws ferrite yuav muab siab impedance ntawm EMI frequencies thiab xoom impedance ntawm tag nrho lwm zaus. Qhov siab tshaj plaws impedance tuaj yeem tau txais ntawm 10 MHz thiab 500 MHz nyob ntawm cov khoom siv ferrite.
Txij li thaum nws ua raws li cov hauv paus ntsiab lus ntawm hluav taws xob engineering, qhov twg AC voltage thiab tam sim no yog sawv cev los ntawm complex tsis, permeability ntawm ib yam khoom yuav qhia tau hais tias ib tug complex parameter muaj xws li cov tiag tiag thiab xav txog tej yam. permeability splits rau hauv ob lub Cheebtsam.Qhov tiag (μ') sawv cev rau qhov reactive ib feem, uas yog nyob rau hauv theem nrog rau alternating magnetic teb [2], thaum lub tswv yim ib feem (μ") sawv cev rau cov poob, uas yog tawm ntawm theem nrog lub alternating magnetic teb. Cov no tuaj yeem qhia tau raws li cov khoom sib txuas (μs'μs") lossis hauv cov khoom sib luag (µp'µp"). Cov duab nyob rau hauv daim duab 1, 2, thiab 3 qhia cov series ntawm cov complex thawj permeability raws li ib tug muaj nuj nqi ntawm zaus rau peb ferrite cov ntaub ntawv. Cov khoom siv hom 73 yog manganese-zinc ferrite, thawj zaug sib nqus Cov conductivity yog 2500. Cov khoom siv 43 yog nickel zinc ferrite nrog thawj permeability ntawm 850. Cov khoom siv hom 61 yog nickel zinc ferrite nrog thawj permeability ntawm 125.
Kev tsom mus rau cov khoom sib txuas ntawm hom 61 cov khoom siv hauv daim duab 3, peb pom tias qhov tseeb ntawm qhov permeability, μs ', tseem nyob tas li nrog kev nce zaus mus txog rau qhov tseem ceeb zaus, thiab tom qab ntawd txo qis.Qhov poob lossis μs "nce thiab ces peaks li μs ' ntog. Qhov kev txo qis hauv μs yog vim qhov pib ntawm ferrimagnetic resonance. [3] Nws yuav tsum tau muab sau tseg tias qhov siab dua qhov permeability, qhov ntau dua qhov zaus. Qhov kev sib raug zoo sib txawv no tau pom thawj zaug los ntawm Snoek thiab muab cov qauv hauv qab no:
Qhov twg: ƒres = μs” zaus ntawm qhov siab tshaj plaws γ = gyromagnetic piv = 0.22 x 106 A-1 m μi = thawj permeability Msat = 250-350 Am-1
Txij li thaum ferrite cores siv nyob rau hauv cov teeb liab qis thiab cov ntawv siv fais fab tsom rau qhov tsis sib nqus hauv qab no zaus, ferrite manufacturers tsis tshua luam tawm permeability thiab / los yog cov ntaub ntawv poob ntawm ntau zaus.Txawm li cas los xij, cov ntaub ntawv ntau dua yog qhov tseem ceeb thaum qhia txog ferrite cores rau EMI suppression.
Cov yam ntxwv uas feem ntau cov tuam txhab ferrite qhia meej rau cov khoom siv rau EMI kev tawm tsam yog impedance.Impedance tau yooj yim ntsuas ntawm cov khoom lag luam analyzer nrog cov ntawv nyeem ncaj qha. Hmoov tsis zoo, impedance feem ntau tau teev nyob rau ntawm qhov tshwj xeeb zaus thiab yog ib qho scalar sawv cev rau qhov loj ntawm qhov nyuaj. impedance vector.Thaum cov ntaub ntawv no muaj txiaj ntsig, nws feem ntau tsis txaus, tshwj xeeb tshaj yog thaum ua qauv kev ua haujlwm ntawm ferrites.Ua tiav qhov no, tus nqi impedance thiab theem kaum ntawm cov khoom, los yog complex permeability ntawm cov khoom tshwj xeeb, yuav tsum muaj.
Tab sis txawm tias ua ntej pib ua qauv kev ua tau zoo ntawm ferrite Cheebtsam hauv Circuit Court, tus tsim qauv yuav tsum paub cov hauv qab no:
qhov twg μ' = tiag ib feem ntawm complex permeability μ "= xav txog ib feem ntawm complex permeability j = xav vector ntawm chav tsev Lo = cua core inductance
Lub impedance ntawm cov tub ntxhais hlau tseem suav hais tias yog qhov sib xyaw ua ke ntawm inductive reactance (XL) thiab qhov poob tsis kam (Rs), ob qho tib si ntawm cov zaus nyob ntawm qhov tsis sib xws.
qhov twg: Rs = tag nrho series kuj = Rm + Re Rm = sib npaug series kuj vim sib nqus losses Re = sib npaug series kuj rau tooj liab poob
Ntawm qhov tsawg zaus, qhov impedance ntawm cov khoom feem ntau yog inductive.Raws li qhov zaus nce, qhov inductance txo qis thaum qhov poob nce thiab tag nrho cov impedance nce.Daim duab 4 yog ib qho piv txwv ntawm XL, Rs thiab Z piv rau peb cov khoom nruab nrab permeability. .
Tom qab ntawd cov inductive reactance yog proportional rau qhov tseeb ntawm qhov complex permeability, los ntawm Lo, cov cua-core inductance:
Qhov poob kuj tseem yog proportional rau qhov xav txog ib feem ntawm txoj kev permeability los ntawm tib qhov tas li:
Hauv Equation 9, cov khoom tseem ceeb yog muab los ntawm µs ' thiab µs ", thiab cov tub ntxhais geometry yog muab los ntawm Lo.Yog li ntawd, tom qab paub qhov nyuaj permeability ntawm cov ferrites sib txawv, kev sib piv tuaj yeem ua kom tau txais cov khoom tsim nyog tshaj plaws ntawm qhov xav tau. zaus los yog ntau zaus.Tom qab xaiv cov khoom siv zoo tshaj plaws, nws yog lub sijhawm los xaiv cov khoom loj tshaj plaws.Qhov vector sawv cev ntawm complex permeability thiab impedance yog qhia hauv daim duab 5.
Kev sib piv ntawm cov duab tseem ceeb thiab cov ntaub ntawv tseem ceeb rau impedance optimization yog ncaj nraim yog tias cov chaw tsim khoom muab ib daim duab ntawm complex permeability piv rau zaus rau cov ntaub ntawv ferrite pom zoo rau kev siv tshuaj tua kab mob.Hmoov tsis tshua muaj, cov ntaub ntawv no tsis tshua muaj.Txawm li cas los xij, feem ntau cov tuam ntxhab muab thawj permeability thiab poob piv rau zaus. curves.Los ntawm cov ntaub ntawv no ib qho kev sib piv ntawm cov ntaub ntawv siv los optimize core impedance tuaj yeem muab tau.
Xa mus rau daim duab 6, thawj qhov permeability thiab dissipation yam [4] ntawm Fair-Rite 73 cov khoom siv piv rau zaus, piv txwv li tus tsim qauv xav kom lav qhov siab tshaj plaws impedance ntawm 100 thiab 900 kHz.73 cov ntaub ntawv raug xaiv.Rau qauv qauv, tus tsim qauv kuj yuav tsum nkag siab txog cov reactive thiab resistive qhov chaw ntawm impedance vector ntawm 100 kHz (105 Hz) thiab 900 kHz.Cov ntaub ntawv no tuaj yeem muab tau los ntawm daim duab hauv qab no:
Ntawm 100kHz μs ' = μi = 2500 thiab (Tan δ / μi) = 7 x 10-6 vim Tan δ = μs "/ μs' ces μs" = (Tan δ / μi) x (μi) 2 = 43.8
Nws yuav tsum raug sau tseg tias, raws li qhov xav tau, μ " ntxiv me ntsis rau tag nrho cov permeability vector ntawm qhov tsawg zaus. Lub impedance ntawm cov tub ntxhais feem ntau yog inductive.
Cov neeg tsim qauv paub tias cov tub ntxhais yuav tsum tau txais # 22 hlau thiab haum rau hauv qhov chaw 10 hli x 5 hli.Lub puab txoj kab uas hla yuav raug teev raws li 0.8 hli.Yuav daws tau qhov kwv yees impedance thiab nws cov khoom, ua ntej xaiv ib lub hlaws nrog ib txoj kab uas hla ntawm sab nraud. 10 hli thiab qhov siab ntawm 5 hli:
Z = ωLo (2500.38) = (6.28 x 105) x .0461 x log10 (5/.8) x 10 x (2500.38) x 10-8 = 5.76 ohms ntawm 100 kHz
Nyob rau hauv cov ntaub ntawv no, raws li nyob rau hauv feem ntau, lub siab tshaj plaws impedance yog tiav los ntawm kev siv ib tug me me OD nrog ib tug ntev ntev.Yog hais tias tus ID yog loj, piv txwv li 4mm, thiab vice versa.
Tib txoj hauv kev tuaj yeem siv tau yog tias cov phiaj xwm ntawm impedance ib chav Lo thiab theem lub kaum sab xis piv rau zaus tau muab.Daim duab 9, 10 thiab 11 sawv cev rau cov nkhaus no rau tib yam peb cov ntaub ntawv siv hauv no.
Cov neeg tsim qauv xav kom lav qhov siab tshaj plaws impedance tshaj li ntawm 25 MHz mus rau 100 MHz zaus ntau yam.Qhov chaw muaj board yog dua 10mm x 5mm thiab cov tub ntxhais yuav tsum lees txais #22 awg hlau.Rau daim duab 7 rau chav tsev impedance Lo ntawm peb cov ntaub ntawv ferrite, los yog Daim duab 8 rau qhov nyuaj permeability ntawm tib yam peb cov ntaub ntawv, xaiv cov khoom siv 850 μi.[5] Siv cov duab hauv daim duab 9, Z / Lo ntawm cov khoom nruab nrab permeability yog 350 x 108 ohm / H ntawm 25 MHz. daws rau qhov kwv yees impedance:
Cov kev sib tham yav dhau los xav tias qhov tseem ceeb ntawm kev xaiv yog cylindrical.Yog ferrite cores yog siv rau cov ribbon ca cables, bundled cables, los yog perforated daim hlau, kev xam ntawm Lo yuav nyuaj dua, thiab ncaj ncaj txoj hauv kev ntev thiab cov nuj nqis hauv cheeb tsam yuav tsum tau txais. los laij cov tub ntxhais huab cua inductance .Qhov no tuaj yeem ua tau los ntawm kev ua lej slicing cov tub ntxhais thiab ntxiv cov laij lej ntev thiab thaj chaw sib nqus rau txhua daim hlais.Txawm li cas los xij, qhov nce lossis txo qhov impedance yuav yog proportional rau qhov nce los yog txo. qhov siab / ntev ntawm ferrite core.[6]
Raws li tau hais, feem ntau cov tuam ntxhab qhia cov cores rau EMI daim ntawv thov nyob rau hauv cov nqe lus ntawm impedance, tab sis cov neeg siv kawg feem ntau yuav tsum paub qhov attenuation.Qhov kev sib raug zoo uas muaj nyob nruab nrab ntawm ob qhov no yog:
Qhov kev sib raug zoo no nyob ntawm qhov impedance ntawm lub hauv paus tsim lub suab nrov thiab impedance ntawm lub load tau txais lub suab nrov.Cov txiaj ntsig no feem ntau yog cov lej nyuaj, uas nws qhov ntau tuaj yeem ua tsis kawg, thiab tsis yooj yim rau tus tsim qauv.Xaiv tus nqi ntawm 1 ohm rau lub load thiab qhov impedances, uas tuaj yeem tshwm sim thaum lub hauv paus yog hloov pauv lub zog hluav taws xob thiab thauj khoom ntau yam tsis muaj impedance circuits, yooj yim rau kev sib npaug thiab tso cai rau kev sib piv ntawm attenuation ntawm ferrite cores.
Daim duab nyob rau hauv daim duab 12 yog ib txheej ntawm nkhaus uas qhia txog kev sib raug zoo ntawm cov ntaub thaiv npog impedance thiab attenuation rau ntau yam txiaj ntsig ntawm load ntxiv rau lub tshuab hluav taws xob impedance.
Daim duab 13 yog qhov sib npaug ntawm qhov cuam tshuam nrog kev tawm tsam sab hauv Zs. Lub teeb liab cuam tshuam yog tsim los ntawm series impedance Zsc ntawm cov tub ntxhais suppressor thiab cov load impedance ZL.
Cov duab 14 thiab 15 yog cov duab ntawm impedance piv rau qhov kub thiab txias rau tib yam peb cov ntaub ntawv ferrite.Qhov ruaj khov tshaj plaws ntawm cov ntaub ntawv no yog 61 cov ntaub ntawv nrog 8% txo impedance ntawm 100º C thiab 100 MHz.Qhov sib piv, 43 cov ntaub ntawv qhia txog 25. % poob rau hauv impedance ntawm tib zaus thiab qhov kub thiab txias.Cov nkhaus no, thaum muab, tuaj yeem siv los kho cov chav ntsuas kub impedance yog tias attenuation ntawm qhov kub siab yuav tsum tau.
Raws li qhov kub thiab txias, DC thiab 50 lossis 60 Hz cov khoom siv tam sim no tseem cuam tshuam rau tib yam khoom siv ferrite, uas ua rau cov tub ntxhais qis impedance.Daim duab 16, 17 thiab 18 yog cov qauv nkhaus uas qhia txog qhov cuam tshuam ntawm kev tsis ncaj ncees ntawm impedance ntawm cov khoom siv ferrite. .Qhov kev nkhaus no piav qhia txog qhov impedance degradation raws li kev ua haujlwm ntawm lub zog teb rau cov khoom siv tshwj xeeb raws li kev ua haujlwm ntawm zaus.Nws yuav tsum tau muab sau tseg tias cov nyhuv ntawm qhov kev tsis ncaj ncees diminishes raws li qhov zaus nce.
Txij li cov ntaub ntawv no tau muab tso ua ke, Fair-Rite Products tau qhia ob yam khoom tshiab.Our 44 yog cov khoom siv nickel-zinc nruab nrab permeability thiab peb 31 yog cov khoom siv manganese-zinc siab permeability.
Daim duab 19 yog ib daim phiaj ntawm impedance piv rau zaus rau cov hlaws ntawm tib qhov loj hauv 31, 73, 44 thiab 43 cov ntaub ntawv.Cov khoom siv 44 yog ib qho kev txhim kho 43 cov khoom siv nrog ntau dua DC resistivity, 109 ohm cm, zoo thermal shock zog, kub stability thiab siab dua Curie kub (Tc).Cov 44 khoom muaj me ntsis impedance ntau zaus piv rau peb cov khoom 43.Cov khoom nyob ruaj ruaj 31 nthuav tawm cov impedance siab dua li 43 lossis 44 dhau ntawm tag nrho cov kev ntsuas ntau zaus.Lub 31 yog tsim los txo cov Dimension resonance teeb meem uas cuam tshuam rau qhov tsawg zaus kev ua haujlwm ntawm cov manganese-zinc cores loj thiab tau ua tiav siv rau cable connector suppression cores thiab loj toroidal cores.Daim duab 20 yog ib daim phiaj ntawm impedance piv rau zaus rau 43, 31, thiab 73 cov ntaub ntawv rau Kev Ncaj Ncees -Rite cores nrog 0.562 "OD, 0.250 ID, thiab 1.125 HT. Thaum muab piv rau daim duab 19 thiab daim duab 20, nws yuav tsum tau muab sau tseg tias rau cov cores me, rau zaus mus txog 25 MHz, 73 cov khoom yog cov khoom zoo tshaj plaws suppressor. Txawm li cas los xij, raws li qhov tseem ceeb hla ntu nce, qhov siab tshaj plaws zaus txo. Raws li pom nyob rau hauv cov ntaub ntawv nyob rau hauv daim duab 20, 73 yog qhov zoo tshaj plaws Qhov siab tshaj plaws zaus yog 8 MHz. Nws tseem tsim nyog sau cia tias 31 cov khoom ua tau zoo nyob rau hauv ntau zaus ntawm 8 MHz txog 300 MHz. Txawm li cas los xij, raws li manganese zinc ferrite, cov khoom siv 31 muaj qhov qis qis dua ntawm 102 ohms -cm, thiab ntau impedance hloov nrog huab cua hloov pauv.
Glossary Air Core Inductance – Lo (H) Cov inductance uas yuav ntsuas yog tias cov tub ntxhais muaj qhov sib txawv permeability thiab cov flux faib tseem nyob tas li.General formula Lo = 4π N2 10-9 (H) C1 Nplhaib Lo = .0461 N2 log10 (OD /ID) Ht 10-8 (H) Dimensions yog nyob rau hauv mm
Attenuation - A (dB) Qhov txo qis ntawm cov teeb liab amplitude hauv kev sib kis ntawm ib qho taw tes mus rau lwm qhov.
Core Constant – C1 (cm-1) Cov sum ntawm cov magnetic path lengths ntawm txhua seem ntawm lub magnetic Circuit Court muab faib los ntawm cov sib nqus sib nqus cheeb tsam ntawm tib seem.
Core Constant – C2 (cm-3) Qhov sib npaug ntawm qhov sib nqus Circuit Court ntev ntawm txhua ntu ntawm cov hlau nplaum sib nqus muab faib los ntawm cov square ntawm cov sib nqus sib nqus ntawm tib seem.
Qhov ntev ntawm qhov sib nqus ntawm thaj tsam Ae (cm2), txoj kab ntev le (cm) thiab qhov ntim Ve (cm3) Rau qhov muab cov tub ntxhais geometry, nws xav tias qhov sib nqus txoj kab ntev, qhov chaw hla ntu, thiab ntim ntawm lub toroidal core muaj cov khoom siv tib yam li Cov khoom siv yuav tsum muaj cov khoom sib nqus sib npaug rau cov tub ntxhais muab.
Field Strength – H (Oersted) Parameter characterizing qhov loj ntawm lub teb zog.H = .4 π NI/le (Oersted)
Flux Density – B (Gaussian) Qhov sib thooj parameter ntawm induced magnetic teb nyob rau hauv cheeb tsam ib txwm mus rau txoj kev flux.
Impedance – Z (ohm) Lub impedance ntawm ib tug ferrite yuav qhia tau hais tias nyob rau hauv cov nqe lus ntawm nws complex permeability.Z = jωLs + Rs = jωLo(μs'- jμs”) (ohm)
Loss Tangent - ​​tan δ Qhov poob tangent ntawm ferrite yog sib npaug rau qhov sib npaug ntawm Circuit Court Q.
Loss Factor - tan δ / μi Theem tshem tawm ntawm cov khoom tseem ceeb ntawm magnetic flux ntom thiab lub zog teb nrog thawj permeability.
Sib Nqus Permeability - μ Qhov sib nqus permeability tau los ntawm qhov sib nqus ntawm qhov sib nqus flux ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom-
Amplitude permeability, μa - thaum tus nqi teev ntawm flux ceev yog ntau dua tus nqi siv rau thawj permeability.
Zoo Permeability, μe - Thaum txoj kev sib nqus tau tsim nrog ib lossis ntau qhov sib txawv ntawm huab cua, qhov permeability yog qhov permeability ntawm cov khoom siv hypothetical homogeneous uas yuav muab tib yam tsis txaus siab.
Hauv Kev Ua Raws Cai yog qhov tseem ceeb tshaj plaws ntawm cov xov xwm, ntaub ntawv, kev kawm thiab kev tshoov siab rau cov kws tshaj lij hluav taws xob thiab hluav taws xob engineering.
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