nkhani

M'dziko lathu labwino, chitetezo, khalidwe ndi ntchito ndizofunika kwambiri.Nthawi zambiri, mtengo wa gawo lomaliza, kuphatikizapo ferrite, wakhala chinthu chodziwikiratu.Nkhaniyi ikufuna kuthandiza akatswiri opanga mapangidwe kupeza zipangizo zina za ferrite kuti achepetse. mtengo.
Zomwe zimafunidwa zamkati ndi geometry yapakati zimatsimikiziridwa ndi ntchito iliyonse.Makhalidwe omwe amawongolera magwiridwe antchito azizindikiro zotsika ndi kuthekera (makamaka kutentha), kutayika kwapakati, komanso kukhazikika kwamphamvu kwa maginito pakapita nthawi ndi kutentha.Mapulogalamu amaphatikiza ma-Q Ma inductors, ma inductors amtundu wamba, ma burodibandi, ofananira ndi ma pulse transformers, zinthu za mlongoti wa wailesi, ndi zobwereza zogwira ntchito komanso zopanda mphamvu. kulipiritsa batire yagalimoto yamagetsi, maginito amplifiers, zosinthira DC-DC, zosefera mphamvu, ma coil poyatsira, ndi zosinthira.
Chinthu chamkati chomwe chimakhudza kwambiri ntchito yofewa ya ferrite pakuponderezedwa ndizovuta zovuta [1], zomwe zimayenderana ndi kulepheretsa kwapakati. ).Choyamba, komanso chocheperako, chimakhala ngati chishango chothandiza, pomwe ma ferrite amagwiritsidwa ntchito kupatula ma conductor, zigawo kapena mabwalo kuchokera kumadera osokera a electromagnetic field. fyuluta, mwachitsanzo inductance - capacitive pa otsika mafupipafupi ndi dissipation pa ma frequency apamwamba.Kachitatu ndi kofala ntchito ndi pamene ferrite cores ntchito pawokha chigawo otsogolera kapena bolodi mabwalo. M'magawo achiwiri ndi achitatu, ma ferrite cores amapondereza EMI pochotsa kapena kuchepetsa kwambiri mafunde afupipafupi omwe amakokedwa ndi magwero a EMI. M'lingaliro, ferrite yabwino ingapereke kulepheretsa kwakukulu kwa maulendo a EMI ndi zero impedance pa ma frequency ena onse. Kulepheretsa kwakukulu kumatha kupezeka pakati pa 10 MHz ndi 500 MHz kutengera zinthu za ferrite.
Popeza zimagwirizana ndi mfundo zaukadaulo wamagetsi, pomwe magetsi a AC ndi apano akuimiridwa ndi magawo ovuta, kutulutsa kwazinthu kumatha kuwonetsedwa ngati gawo lovuta lomwe lili ndi magawo enieni komanso ongoyerekeza.Izi zikuwonetsedwa pamayendedwe apamwamba, komwe Gawo lenileni (μ') limayimira gawo lokhazikika, lomwe lili mugawo limodzi ndi mphamvu ya maginito yosinthira [2], pomwe gawo longoyerekeza (μ”) limayimira zotayika, zomwe zatha kusintha maginito.Izi zitha kufotokozedwa ngati zigawo zingapo (μs'μs”) kapena mugawo lofananira (µp'µp”).Ma graph mu Zithunzi 1, 2, ndi 3 akuwonetsa zigawo zingapo za zovuta zoyambira zoyambira ngati ntchito yafupipafupi yazinthu zitatu za ferrite.Mtundu wa zinthu 73 ndi manganese-zinc ferrite, maginito oyambira The conductivity ndi 2500. Mtundu wa zinthu 43 ndi faife tambala zinki ferrite ndi permeability koyamba 850. Mtundu wa zinthu 61 ndi faifi tambala zinki ferrite ndi permeability koyamba 125.
Poyang'ana pa mndandanda wa chigawo cha mtundu wa 61 mu Chithunzi 3, tikuwona kuti gawo lenileni la permeability, μs ', limakhalabe nthawi zonse ndi kuwonjezereka kwafupipafupi mpaka nthawi yovuta ikufika, ndiyeno imachepetsa mofulumira.Kutayika kapena μs "kukukwera ndiyeno nsonga ngati mathithi a μs.Kutsika kwa μs'ku kumachitika chifukwa cha kuyambika kwa ferrimagnetic resonance.[3] Tiyenera kuzindikira kuti kumtunda kwa permeability, kumapangitsanso kuchepa kwafupipafupi.Ubale wosiyanawu udawonedwa koyamba ndi Snoek ndipo adapereka njira iyi:
kumene: ƒres = μs” pafupipafupi γ = gyromagnetic chiŵerengero = 0.22 x 106 A-1 m μi = permeability koyamba Msat = 250-350 Am-1
Popeza ma ferrite cores omwe amagwiritsidwa ntchito pamlingo wochepa wa siginecha ndi kugwiritsa ntchito mphamvu kumayang'ana magawo a maginito omwe ali pansipa pafupipafupi, opanga ma ferrite sasindikiza kaŵirikaŵiri permeability ndi/kapena kutayika kwa data pama frequency apamwamba.
Chikhalidwe chomwe ambiri opanga ma ferrite amafotokozera za zigawo zomwe zimagwiritsidwa ntchito pa kuponderezedwa kwa EMI ndi impedance.Impedance imayesedwa mosavuta pa analyzer yopezeka malonda ndi kuwerenga kwachindunji kwa digito. Impedans vector.Ngakhale kuti chidziwitsochi ndi chamtengo wapatali, nthawi zambiri chimakhala chosakwanira, makamaka pofanizira machitidwe a dera la ferrites.
Koma ngakhale musanayambe kuwonetsa momwe ma ferrite amagwirira ntchito pozungulira, okonza ayenera kudziwa izi:
kumene μ'= gawo lenileni la kupenya kovutirapo μ”= gawo lolingaliridwa la kupenyeka kovutirapo j = vector yongoyerekeza ya unit Lo= air core inductance
Kulepheretsa kwachitsulo pakati kumaganiziridwanso kuti ndi kuphatikiza kwa inductive reactance (XL) ndi kukana kutayika (Rs), zonse zomwe zimadalira pafupipafupi.
komwe: ma Rs = kukana kwathunthu = Rm + Re Rm = kukana kofananira chifukwa cha kutayika kwa maginito Re = kukana kofanana kwa kutayika kwa mkuwa
Pamafupipafupi otsika, kusokoneza kwa chigawocho kumakhala kochititsa chidwi.Pamene mafupipafupi akuwonjezeka, inductance imachepa pamene kutayika kumawonjezeka ndipo kusokoneza kwathunthu kumawonjezeka. .
Ndiye kuyankhidwa kwa inductive kumayenderana ndi gawo lenileni la zovuta zovomerezeka, ndi Lo, air-core inductance:
Kukana kutayika kumakhalanso kolingana ndi gawo longoyerekeza la zovuta zopindika mwanthawi zonse:
Mu Equation 9, zinthu zazikuluzikulu zimaperekedwa ndi µs' ndi µs ", ndipo maziko a geometry amaperekedwa ndi Lo. pafupipafupi kapena ma frequency range.Mutasankha zinthu zabwino kwambiri, ndi nthawi yoti musankhe zigawo zazikulu zazikuluzikulu.Chiwonetsero cha vekitala cha zovuta zovuta komanso zosokoneza zikuwonetsedwa mu Chithunzi 5.
Kuyerekeza kwa mawonekedwe apakati ndi zida zapakatikati pakukhathamiritsa kwa impedance ndikosavuta ngati wopanga akupereka chithunzi cha zovuta zowoneka bwino motsutsana ndi kuchuluka kwa zinthu za ferrite zomwe zimalimbikitsidwa kuti zitheke. curves.Kuchokera mu datayi kufananitsa kwa zinthu zomwe zimagwiritsidwa ntchito kukhathamiritsa core impedance zitha kutengedwa.
Ponena za Chithunzi cha 6, choyambira cha permeability ndi dissipation factor [4] cha Fair-Rite 73 zinthu motsutsana ndi pafupipafupi, poganiza kuti mlengi akufuna kutsimikizira kutsekeka kwakukulu pakati pa 100 ndi 900 kHz.73 zida zidasankhidwa. akuyenera kumvetsetsa mbali zogwira ntchito ndi zotsutsa za vector ya impedance pa 100 kHz (105 Hz) ndi 900 kHz. Izi zikhoza kutengedwa kuchokera ku tchati chotsatirachi:
Pa 100kHz μs ' = μi = 2500 ndi (Tan δ / μi) = 7 x 10-6 chifukwa Tan δ = μs ”/ μs' kenako μs” = (Tan δ / μi) x (μi) 2 = 43.8
Zindikirani kuti, monga momwe zimayembekezeredwa, μ” imawonjezera pang'ono pamlingo wokwanira wokwanira pamafupipafupi otsika awa.The impedance ya pachimake nthawi zambiri inductive.
Okonza amadziwa kuti pachimake chiyenera kuvomereza # 22 waya ndikulowa mu danga la 10 mm x 5 mm. Kuzungulira kwamkati kudzafotokozedwa ngati 0.8 mm. 10 mm ndi kutalika kwa 5 mm:
Z= ωLo (2500.38) = (6.28 x 105) x .0461 x chipika10 (5/.8) x 10 x (2500.38) x 10-8= 5.76 ohms pa 100 kHz
Pankhaniyi, monga nthawi zambiri, kulepheretsa kwakukulu kumatheka pogwiritsa ntchito OD yaying'ono yokhala ndi utali wautali.Ngati ID ndi yayikulu, mwachitsanzo 4mm, ndi mosemphanitsa.
Njira yomweyi ingagwiritsidwe ntchito ngati ziwembu za impedance pa unit Lo ndi gawo la angle motsutsana ndi mafupipafupi zimaperekedwa.
Okonza akufuna kutsimikizira kuti pali vuto lalikulu pa 25 MHz mpaka 100 MHz maulendo afupipafupi. kapena Chithunzi 8 kwa zovuta permeability wa zipangizo zitatu zofanana, kusankha 850 μi zakuthupi.Pogwiritsa ntchito graph mu Chithunzi 9, Z/Lo ya zinthu zapakatikati ndi 350 x 108 ohm/H pa 25 MHz.
Kukambitsirana kwapitaku kumaganiza kuti pachimake chosankha ndi cylindrical.Ngati ma ferrite cores amagwiritsidwa ntchito ngati zingwe za riboni, zingwe zomangika, kapena mbale zopindika, kuwerengera kwa Lo kumakhala kovuta kwambiri, ndipo kutalika kwa njira yolondola komanso madera ogwira mtima ayenera kupezeka. kuwerengera mpweya wapakati inductance .Izi zikhoza kuchitika mwa masamu slicing pachimake ndi kuwonjezera mawerengedwe njira kutalika ndi maginito dera aliyense kagawo. kutalika/utali wa phata la ferrite.[6]
Monga tafotokozera, opanga ambiri amatchula ma cores a EMI applications molingana ndi zolepheretsa, koma wogwiritsa ntchito nthawi zambiri amafunika kudziwa attenuation.Ubale womwe ulipo pakati pa magawo awiriwa ndi:
Ubalewu umadalira kutsekeka kwa gwero lomwe limatulutsa phokoso komanso kutsekeka kwa katundu yemwe akulandira phokosolo.Makhalidwe awa nthawi zambiri amakhala manambala ovuta, omwe mitundu yawo imatha kukhala yopanda malire, ndipo sapezeka mosavuta kwa wopanga.Kusankha mtengo 1 ohm kwa katundu ndi gwero impedances, amene angathe kuchitika pamene gwero ndi lophimba mumalowedwe magetsi ndi katundu ambiri otsika impedance mabwalo, kufewetsa equations ndi kulola kufananiza attenuation wa ferrite cores.
Chithunzi cha Chithunzi 12 ndi ma curve omwe akuwonetsa ubale pakati pa kutsekeka kwa mikanda ya chishango ndi kuchepetsedwa kwa zinthu zambiri zomwe zimafanana za katundu kuphatikiza kulepheretsa kwa jenereta.
Chithunzi 13 ndi gawo lofanana ndi gwero losokoneza lomwe lili ndi kukana kwamkati kwa Zs.Chizindikiro chosokoneza chimapangidwa ndi mndandanda wa impedance Zsc wa suppressor core ndi katundu wa impedance ZL.
Zithunzi 14 ndi 15 ndi ma graph a impedance motsutsana ndi kutentha kwa zinthu zitatu zofanana za ferrite.Chokhazikika kwambiri mwa zipangizozi ndi zinthu za 61 ndi kuchepetsa 8% mu impedance pa 100º C ndi 100 MHz. Mosiyana ndi zimenezi, zinthu za 43 zinasonyeza 25 % kutsika kwa impedance pafupipafupi komanso kutentha komweko.Ma curve awa, akaperekedwa, angagwiritsidwe ntchito kusinthira kutentha kwachipinda komwe kumapangidwira ngati kuchepetsedwa kwa kutentha kumafunika.
Mofanana ndi kutentha, mafunde a DC ndi 50 kapena 60 Hz amakhudzanso zinthu zofanana za ferrite, zomwe zimapangitsa kuti pakhale kutsika kwapakati. .Mzerewu umalongosola kuwonongeka kwa impedance monga ntchito ya mphamvu ya kumunda kwa zinthu zinazake monga ntchito yafupipafupi.Ziyenera kuzindikiridwa kuti zotsatira za kukondera zimachepa pamene mafupipafupi akuwonjezeka.
Popeza detayi idapangidwa, Fair-Rite Products yakhazikitsa zida ziwiri zatsopano.Our 44 ndi nickel-zinc medium permeability material ndipo 31 yathu ndi manganese-zinc high permeability material.
Chithunzi 19 ndi chiwembu chotsutsana ndi mafupipafupi a mikanda yofanana ndi 31, 73, 44 ndi 43 zipangizo. The 44 ndi chinthu chopangidwa bwino cha 43 chokhala ndi DC resistivity yapamwamba, 109 ohm cm, katundu wabwino wotenthetsera kutentha, kukhazikika kwa kutentha ndi kutentha. Kutentha kwa Curie (Tc). The 44 ili ndi zopinga zokwera pang'ono poyerekeza ndi mawonekedwe afupipafupi poyerekeza ndi zinthu zathu za 43. Zomwe zimayima 31 zimawonetsa kusokoneza kwakukulu kuposa 43 kapena 44 pamtundu wonse wa ma frequency. Dimensional resonance vuto lomwe limakhudza kutsika kwafupipafupi kuponderezedwa kwa ma manganese-zinc cores ndipo lagwiritsidwa ntchito bwino pazitsulo zolumikizira chingwe ndi ma toroidal cores. -Rite cores yokhala ndi 0.562 ″ OD, 0.250 ID, ndi 1.125 HT.Poyerekeza Chithunzi 19 ndi Chithunzi 20, ziyenera kudziwidwa kuti Kwa ma cores ang'onoang'ono, ma frequency mpaka 25 MHz, zinthu 73 ndiye zinthu zabwino kwambiri zopondereza.Komabe, pamene gawo lalikulu la mtanda likuwonjezeka, kuchuluka kwafupipafupi kumachepa.Monga momwe deta ikusonyezera mu Chithunzi 20, 73 ndi yabwino Kwambiri pafupipafupi ndi 8 MHz.Ndizofunikanso kudziwa kuti zinthu za 31 zimagwira ntchito pafupipafupi kuchokera ku 8 MHz mpaka 300 MHz.Komabe, monga manganese zinc ferrite, zinthu 31 zili ndi mphamvu yotsika kwambiri ya 102 ohms -cm, ndikusintha kwapang'onopang'ono ndi kusintha kwakukulu kwa kutentha.
Glossary Air Core Inductance - Lo (H) The inductance yomwe ingayesedwe ngati pachimake chinali ndi yunifolomu permeability ndipo kugawa kwa flux kumakhalabe kosasintha.General formula Lo= 4π N2 10-9 (H) C1 Ring Lo = .0461 N2 log10 (OD /ID) Ht 10-8 (H) Makulidwe ali mm
Attenuation - A (dB) Kuchepetsa matalikidwe a siginecha pakupatsirana kuchokera ku mfundo imodzi kupita ku ina.
Core Constant - C1 (cm-1) Chiwerengero cha kutalika kwa njira ya maginito ya gawo lililonse la maginito ogawidwa ndi gawo lofananira la maginito a gawo lomwelo.
Core Constant - C2 (cm-3) Chiwerengero cha kutalika kwa maginito ozungulira gawo lililonse la maginito ogawidwa ndi sikweya ya gawo lomwelo la gawo lomwelo.
Miyezo yogwira ntchito ya maginito Ae (cm2), kutalika kwa njira le (cm) ndi voliyumu Ve (cm3) Pa geometry yapakatikati, amalingaliridwa kuti kutalika kwa njira ya maginito, gawo lopingasa, ndi kuchuluka kwa maginito. maziko a toroidal ali ndi zinthu zofanana ndi Zomwe zili ndi maginito zomwe zimafanana ndi pachimake choperekedwa.
Mphamvu Zakumunda – H (Oersted) Chizindikiro chosonyeza kukula kwa mphamvu ya kumunda.H = .4 π NI/le (Oersted)
Kuchulukirachulukira kwa Flux - B (Gaussian) Gawo lofananira la mphamvu ya maginito yomwe idapangidwa m'chigawo chodziwika bwino panjira yotuluka.
Impedance - Z (ohm) Kulepheretsa kwa ferrite kungasonyezedwe potengera zovuta zake.Z = jωLs + Rs = jωLo(μs'- jμs") (ohm)
Loss Tangent - tan δ Kutayika kwa ferrite ndikofanana ndi kubwereza kwa dera Q.
Loss Factor - tan δ/μi Kuchotsa gawo pakati pa magawo ofunikira a kachulukidwe ka maginito ndi mphamvu yakumunda ndikuthekera koyambirira.
Kuthekera kwa Magnetic - μ Kuthekera kwa maginito kochokera ku chiŵerengero cha kachulukidwe ka maginito ndi mphamvu ya maginito ndi...
Amplitude permeability, μa - pamene mtengo wotchulidwa wa kachulukidwe ka flux ndi waukulu kuposa mtengo womwe umagwiritsidwa ntchito poyambira.
Kuthekera Kwabwino, μe - Pamene njira ya maginito imamangidwa ndi mpweya umodzi kapena kuposerapo, kuthekera kwake ndikokwanira kwa zinthu zongoyerekeza zomwe zingapereke kukayikira komweko.
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