nkhani

Chidule

Ma inductors ndi zigawo zofunika kwambiri pakusintha ma converters, monga kusungirako mphamvu ndi zosefera zamagetsi. Pali mitundu yambiri ya inductors, monga ntchito zosiyanasiyana (kuchokera kufupipafupi kufika kufupipafupi), kapena zipangizo zosiyana siyana zomwe zimakhudza makhalidwe a inductor, ndi zina zotero. Ma inductors omwe amagwiritsidwa ntchito posintha masinthidwe ndi maginito apamwamba kwambiri. Komabe, chifukwa cha zinthu zosiyanasiyana monga zida, magwiridwe antchito (monga magetsi ndi magetsi), komanso kutentha kozungulira, mawonekedwe ndi malingaliro omwe amaperekedwa ndi osiyana kwambiri. Choncho, mu mapangidwe a dera, kuwonjezera pa chiwerengero choyambirira cha mtengo wa inductance, mgwirizano pakati pa kulepheretsa kwa inductor ndi kukana kwa AC ndi mafupipafupi, kutayika kwakukulu ndi makhalidwe a machulukitsidwe amakono, ndi zina zotero ziyenera kuganiziridwabe. Nkhaniyi iwonetsa zida zingapo zofunika za inductor ndi mawonekedwe ake, ndikuwongoleranso akatswiri opanga magetsi kuti asankhe ma inductors omwe amapezeka pamalonda.

Mawu Oyamba

Inductor ndi chigawo cha electromagnetic induction induction, chomwe chimapangidwa ndikuzunguliza kuchuluka kwa ma koyilo (koyilo) pa bobbin kapena pachimake ndi waya wotsekeredwa. Koyilo iyi imatchedwa coil inductance kapena Inductor. Malinga ndi mfundo ya ma elekitiromagineti induction, pamene koyilo ndi mphamvu ya maginito zimayenda molumikizana wina ndi mzake, kapena koyiloyo ipanga maginito osinthika kudzera pakusintha kwapano, voteji yomwe imapangitsa kuti ikanize kusintha kwa maginito oyambilira, ndipo chikhalidwe ichi choletsa kusintha kwamakono chimatchedwa inductance.

Maonekedwe a mtengo wa inductance ndi monga chilinganizo (1), chomwe chimayenderana ndi maginito permeability, masikweya a makhonde mokhotakhota N, ndi ofanana ndi maginito ozungulira gawo Ae, ndipo ndi mosiyana molingana ndi ofanana maginito a dera kutalika le. . Pali mitundu yambiri ya inductance, iliyonse yoyenera ntchito zosiyanasiyana; inductance imakhudzana ndi mawonekedwe, kukula, njira yokhotakhota, kuchuluka kwa kutembenuka, ndi mtundu wazinthu zapakati zamaginito.

(1)

Kutengera mawonekedwe a chitsulo pachimake, inductance imaphatikizapo toroidal, E core ndi ng'oma; kutengera zachitsulo pachimake chuma, pali makamaka ceramic pachimake ndi ziwiri zofewa maginito mitundu. Iwo ndi ferrite ndi zitsulo ufa. Kutengera kapangidwe kapena ma CD njira, pali waya bala, Mipikisano wosanjikiza, ndi kuumbidwa, ndi waya bala ali osatetezedwa ndi theka la maginito guluu Kutetezedwa (theka-otetezedwa) ndi kutetezedwa (kutetezedwa), etc.

Inductor imagwira ntchito ngati chiwongolero chachifupi molunjika pakali pano, ndipo imakhala ndi vuto lalikulu pakusintha kwapano. Zomwe zimagwiritsidwa ntchito m'mabwalo zimaphatikizapo kutsamwitsa, kusefa, kukonza, ndi kusunga mphamvu. Pogwiritsa ntchito chosinthira chosinthira, inductor ndiye chinthu chofunikira kwambiri chosungira mphamvu, ndikupanga fyuluta yotsika ndi capacitor yotulutsa kuti muchepetse kutulutsa kwamagetsi, kotero imagwiranso ntchito yofunika kwambiri pakusefa.

Nkhaniyi ifotokoza zamitundu yosiyanasiyana ya ma inductors ndi mawonekedwe awo, komanso mawonekedwe ena amagetsi a ma inductors, ngati chidziwitso chofunikira pakusankha ma inductors pakupanga madera. Muchitsanzo chogwiritsira ntchito, momwe mungawerengere mtengo wa inductance ndi momwe mungasankhire wokhazikika wopezeka pamalonda adzadziwitsidwa kudzera mu zitsanzo zothandiza.

Mtundu wa zinthu zapakati

Ma inductors omwe amagwiritsidwa ntchito posintha masinthidwe ndi maginito apamwamba kwambiri. Zomwe zili pakatikati zimakhudza kwambiri mawonekedwe a inductor, monga kutsekeka ndi ma frequency, mtengo wa inductance ndi ma frequency, kapena machulukidwe apakati. Zotsatirazi zikuwonetsa kufananiza kwa zida zingapo zachitsulo zapakati komanso mawonekedwe ake monga gawo lofunikira posankha ma inductors:

1. Ceramic pachimake

Ceramic pachimake ndi chimodzi mwa zinthu wamba inductance zipangizo. Amagwiritsidwa ntchito makamaka popereka mawonekedwe othandizira omwe amagwiritsidwa ntchito pomangirira koyilo. Imatchedwanso "air core inductor". Chifukwa chitsulo chachitsulo chomwe chimagwiritsidwa ntchito ndi zinthu zopanda maginito zomwe zimakhala ndi kutentha kochepa kwambiri, mtengo wa inductance ndi wokhazikika pa kutentha kwa ntchito. Komabe, chifukwa cha zinthu zopanda maginito monga sing'anga, inductance ndi yotsika kwambiri, yomwe si yoyenera kwambiri kugwiritsa ntchito otembenuza mphamvu.

2. Ferrite

Pachimake cha ferrite chomwe chimagwiritsidwa ntchito pafupipafupi ma inductors apamwamba kwambiri ndi gawo la ferrite lomwe lili ndi nickel zinc (NiZn) kapena manganese zinc (MnZn), chomwe ndi chinthu chofewa cha maginito ferromagnetic chokhala ndi mphamvu zochepa. Chithunzi 1 chikuwonetsa hysteresis curve (BH loop) ya maginito ambiri. Mphamvu yokakamiza HC ya maginito imatchedwanso mphamvu yokakamiza, zomwe zikutanthauza kuti pamene maginito apangidwa ndi maginito kuti azitha kudzaza maginito, maginito ake (magnetization) amachepetsedwa mpaka ziro Mphamvu yofunikira ya maginito panthawiyo. Kuchepetsa kukakamiza kumatanthawuza kukana kutsika kwa demagnetization komanso kumatanthauza kuchepa kwa hysteresis.

Manganese-zinki ndi faifi tambala-zinki ferrites ndi mkulu permeability (μr), pafupifupi 1500-15000 ndi 100-1000, motero. Kuchuluka kwawo kwa maginito kumapangitsa kuti chitsulo chikhale chokwera kwambiri mu voliyumu inayake. The inductance. Komabe, choyipa chake ndichakuti kuchuluka kwake kovomerezeka kumakhala kochepa, ndipo pachimake chachitsulo chikakhutitsidwa, mphamvu ya maginito imatsika kwambiri. Onani Chithunzi 4 cha kuchepa kwa maginito a maginito a ferrite ndi zitsulo zachitsulo za ufa pamene pakatikati pachitsulo chadzaza. Kuyerekezera. Mukagwiritsidwa ntchito mumagetsi opangira mphamvu, kusiyana kwa mpweya kudzasiyidwa mu dera lalikulu la maginito, lomwe lingathe kuchepetsa permeability, kupewa machulukitsidwe ndi kusunga mphamvu zambiri; pamene kusiyana kwa mpweya kumaphatikizidwa, chiwopsezo chofanana chofanana chikhoza kukhala cha 20- Pakati pa 200. Popeza kuti resistivity yapamwamba ya zinthu yokha imatha kuchepetsa kutayika komwe kumachitika chifukwa cha eddy current, kutayika kumakhala kochepa pamafupipafupi, ndipo kuli koyenera kwambiri otembenuza ma frequency apamwamba, ma inductors a EMI ndi ma inductors osungira mphamvu osinthira mphamvu. Pankhani ya ma frequency opareshoni, faifi tambala-zinki ferrite ndiyoyenera kugwiritsidwa ntchito (> 1 MHz), pomwe manganese-zinki ferrite ndiyoyenera magulu otsika pafupipafupi (<2 MHz).

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Chithunzi 1. The hysteresis curve of the magnetic core (BR: remanence; BSAT: saturation magnetic flux density)

3. Pachimake chitsulo cha ufa

Powder iron cores ndizinthu zofewa za maginito ferromagnetic. Amapangidwa ndi ma aloyi achitsulo a ufa wamitundu yosiyanasiyana kapena ufa wachitsulo wokha. Fomuyi ili ndi zinthu zopanda maginito zomwe zimakhala ndi kukula kwake kosiyanasiyana, kotero kuti machulukidwe pamapindikira ndi ofatsa. Pakatikati pa chitsulo cha ufa nthawi zambiri amakhala toroidal. Chithunzi 2 chikuwonetsa pachimake chachitsulo cha ufa ndi mawonekedwe ake apakati.

Zitsulo zachitsulo zodziwika bwino zimaphatikizapo iron-nickel-molybdenum alloy (MPP), sendust (Sendust), iron-nickel alloy (high flux) ndi iron powder core (iron powder). Chifukwa cha zigawo zosiyana, makhalidwe ake ndi mitengo imakhalanso yosiyana, yomwe imakhudza kusankha kwa inductors. Zotsatirazi zikuwonetsa mitundu yayikulu yomwe tatchulayi ndikufanizira mawonekedwe awo:

A. Iron-nickel-molybdenum alloy (MPP)

Fe-Ni-Mo alloy amafupikitsidwa ngati MPP, chomwe ndi chidule cha ufa wa molypermalloy. The permeability wachibale ndi za 14-500, ndi machulukitsidwe maginito flux kachulukidwe ndi za 7500 Gauss (Gauss), amene ali apamwamba kuposa machulukitsidwe maginito flux kachulukidwe ferrite (za 4000-5000 Gauss). Ambiri kunja. MPP ili ndi chitsulo chochepa kwambiri ndipo imakhala ndi kutentha kwabwino kwambiri pakati pa zitsulo zachitsulo. Mphamvu yakunja ya DC ikafika pa ISAT yomwe ilipo, kuchuluka kwa inductance kumachepa pang'onopang'ono popanda kuchepetsedwa mwadzidzidzi. MPP ili ndi magwiridwe antchito abwinoko koma okwera mtengo, ndipo nthawi zambiri imagwiritsidwa ntchito ngati inductor yamagetsi ndi kusefa kwa EMI kwa otembenuza mphamvu.

B. Kutumiza

Chitsulo chachitsulo-silicon-aluminium alloy iron core ndi chitsulo chachitsulo chopangidwa ndi chitsulo, silicon, ndi aluminiyamu, chokhala ndi maginito amtundu wa 26 mpaka 125. Kutayika kwachitsulo kuli pakati pa chitsulo cha ufa ndi MPP ndi chitsulo-nickel alloy. . Kuchuluka kwa maginito kuchulukirachulukira ndikokwera kuposa MPP, pafupifupi 10500 Gauss. Kukhazikika kwa kutentha ndi mawonekedwe apano ndi otsika pang'ono kwa MPP ndi aloyi yachitsulo-nickel, koma kuposa chitsulo chachitsulo chachitsulo ndi pakatikati pa ferrite, ndipo mtengo wake ndi wotsika mtengo kuposa MPP ndi aloyi yachitsulo-nickel. Amagwiritsidwa ntchito kwambiri mu kusefa kwa EMI, mabwalo amagetsi owongolera (PFC) ndi ma inductors amagetsi osinthira magetsi.

C. Iron-nickel alloy (high flux)

Chigawo chachitsulo-nickel alloy chimapangidwa ndi chitsulo ndi faifi tambala. Chibale maginito permeability ndi za 14-200. Kutayika kwachitsulo ndi kukhazikika kwa kutentha kuli pakati pa MPP ndi iron-silicon-aluminium alloy. Pakatikati pa iron-nickel alloy core imakhala ndi kuchuluka kwamphamvu kwambiri kwa maginito, pafupifupi 15,000 Gauss, ndipo imatha kupirira mafunde apamwamba a DC, ndipo mawonekedwe ake a DC nawonso ndi abwinoko. Kuchuluka kwa ntchito: Kuwongolera kwamphamvu kwamphamvu, inductance yosungirako mphamvu, inductance fyuluta, chosinthira ma frequency apamwamba a flyback converter, etc.

D. Ufa wachitsulo

Chitsulo chachitsulo chachitsulo chimapangidwa ndi tinthu tating'ono ting'onoting'ono tachitsulo tomwe timakhala ndi tinthu tating'onoting'ono tomwe timatsekeredwa. Njira yopangira imapangitsa kuti ikhale ndi mpweya wogawidwa. Kuphatikiza pa mawonekedwe a mphete, mawonekedwe wamba wachitsulo wachitsulo alinso ndi mtundu wa E ndi mitundu yopondaponda. Kuthekera kwa maginito kwapakati pa ufa wachitsulo kumakhala pafupifupi 10 mpaka 75, ndipo kuchulukitsitsa kwamphamvu kwa maginito kumakhala pafupifupi 15000 Gauss. Pakati pazitsulo zachitsulo za ufa, chitsulo chachitsulo chimakhala ndi chitsulo chotayika kwambiri koma mtengo wotsika kwambiri.

Chithunzi 3 chikuwonetsa BH ma curve a PC47 manganese-zinc ferrite opangidwa ndi TDK ndi zitsulo zachitsulo za ufa -52 ndi -2 zopangidwa ndi MICROMETALS; Kuthekera kwa maginito a manganese-zinc ferrite ndikokwera kwambiri kuposa zitsulo zachitsulo za ufa ndipo kumadzaza Kuchuluka kwa maginito kumakhalanso kosiyana kwambiri, ferrite ndi pafupifupi 5000 Gauss ndi chitsulo chachitsulo chachitsulo ndi choposa 10000 Gauss.

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Chithunzi 3. BH yokhotakhota ya manganese-zinki ferrite ndi chitsulo cha ufa wazitsulo zosiyanasiyana

Mwachidule, mawonekedwe a machulukitsidwe achitsulo chachitsulo ndi osiyana; pamene machulukitsidwe panopa kuposa, maginito permeability wa pachimake ferrite adzagwa kwambiri, pamene chitsulo ufa pachimake akhoza pang'onopang'ono kuchepa. Chithunzi 4 chikuwonetsa kutsika kwa maginito kutsika kwapakati pachitsulo chachitsulo chokhala ndi maginito omwewo komanso ferrite yokhala ndi kusiyana kwa mpweya pansi pa mphamvu zosiyanasiyana zamaginito. Izi zikufotokozeranso kulowetsedwa kwa chigawo cha ferrite, chifukwa kutsekemera kumatsika kwambiri pamene pachimake chodzaza, monga momwe tingawonere kuchokera ku equation (1), kumapangitsanso kuti inductance igwe kwambiri; pamene ufa pachimake ndi kugawira mpweya kusiyana, ndi maginito permeability Mlingo amachepetsa pang'onopang'ono pamene chitsulo pachimake zimakhuta, kotero inductance amachepetsa mofatsa, ndiko kuti, ali bwino DC kukondera makhalidwe. Pogwiritsira ntchito otembenuza mphamvu, khalidweli ndilofunika kwambiri; ngati kuchulukitsidwa kwapang'onopang'ono kwa inductor sikuli bwino, inductor panopa ikukwera mpaka ku saturation panopa, ndipo kutsika kwadzidzidzi kwa inductance kumapangitsa kuti kupanikizika kwaposachedwa kwa kristalo wosinthika kukwera kwambiri, zomwe zimakhala zosavuta kuwononga.

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Chithunzi 4. Maginito permeability dontho makhalidwe a ufa chitsulo pakati ndi ferrite chitsulo pakati ndi mpweya kusiyana pansi osiyana maginito mphamvu.

Makhalidwe amagetsi a inductor ndi kapangidwe ka phukusi

Mukapanga chosinthira chosinthira ndikusankha chowongolera, mtengo wa inductance L, impedance Z, AC resistance ACR ndi Q value (quality factor), yovotera IDC yapano ndi ISAT, ndi kutayika koyambira (kutayika koyambira) ndi mawonekedwe ena ofunikira amagetsi onse Ayenera. kuganiziridwa. Kuphatikiza apo, kapangidwe kake ka inductor kadzakhudza kukula kwa kutayikira kwa maginito, komwe kumakhudzanso EMI. Otsatirawa akambirana za zomwe tazitchulazi padera monga zoganizira posankha ma inductors.

1. Mtengo wa inductance (L)

Mtengo wa inductance wa inductance ndiye gawo lofunikira kwambiri pamapangidwe ozungulira, koma liyenera kuyang'aniridwa ngati mtengo wa inductance ndi wokhazikika pama frequency ogwiritsira ntchito. Mtengo wodziwika wa inductance nthawi zambiri umayesedwa pa 100 kHz kapena 1 MHz popanda kukondera kwa DC. Ndipo kuwonetsetsa kuthekera kwa kupanga makina ambiri, kulolerana kwa inductor nthawi zambiri kumakhala ± 20% (M) ndi ± 30% (N). Chithunzi 5 ndi ma inductance-frequency graph ya Taiyo Yuden inductor NR4018T220M yoyezedwa ndi Wayne Kerr's LCR mita. Monga momwe tawonetsera pachithunzichi, curve yamtengo wapatali imakhala yosalala pamaso pa 5 MHz, ndipo mtengo wa inductance ukhoza kuwonedwa ngati wokhazikika. Mu gulu lapamwamba lafupipafupi chifukwa cha resonance yopangidwa ndi parasitic capacitance ndi inductance, mtengo wa inductance udzawonjezeka. Ma frequency a resonance awa amatchedwa ma frequency a self-resonant (SRF), omwe nthawi zambiri amafunika kukhala apamwamba kuposa ma frequency opangira.

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Chithunzi 5, Taiyo Yuden NR4018T220M inductance-frequency character measurement

2. Kusokoneza (Z)

Monga momwe tawonetsera pa Chithunzi 6, chithunzi cha impedance chikhoza kuwonedwanso kuchokera ku machitidwe a inductance pa ma frequency osiyanasiyana. Kulepheretsa kwa inductor kumakhala pafupifupi molingana ndi pafupipafupi (Z=2πfL), kotero kumtunda kwa ma frequency, kuyankha kumakhala kokulirapo kuposa kukana kwa AC, chifukwa chake cholepheretsa chimakhala ngati inductance yoyera (gawo ndi 90˚). Pamaulendo apamwamba, chifukwa cha mphamvu ya parasitic capacitance, malo odziyimira pawokha a impedance amatha kuwoneka. Pambuyo pa mfundo iyi, mpukutuwo umatsika ndipo umakhala wolimba, ndipo gawolo limasintha pang'onopang'ono mpaka -90 ˚.

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3. Q mtengo ndi AC kukana (ACR)

Q mtengo mu tanthawuzo la inductance ndi chiŵerengero cha momwe timachitira ndi kukana, ndiko kuti, chiŵerengero cha gawo lolingalira ndi gawo lenileni la impedance, monga mu formula (2).

(2)

Kumene XL ndi machitidwe a inductor, ndipo RL ndi kukana kwa AC kwa inductor.

Pafupipafupi pafupipafupi, kukana kwa AC ndikokulirapo kuposa momwe zimachitikira chifukwa cha inductance, motero mtengo wake wa Q ndiwotsika kwambiri; pamene mafupipafupi akuwonjezeka, zomwe zimachitika (pafupifupi 2πfL) zimakhala zazikulu komanso zokulirapo, ngakhale kukana chifukwa cha zotsatira za khungu (khungu) ndi kuyandikira (kuyandikira) zotsatira zake zimakhala zazikulu komanso zazikulu, ndipo mtengo wa Q ukuwonjezeka ndi mafupipafupi. ; poyandikira SRF, kutengera kwa inductive kumachepetsedwa pang'onopang'ono ndi capacitive reactance, ndipo mtengo wa Q umakhala wocheperako; pamene SRF ikukhala ziro, chifukwa mayendedwe a inductive ndi capacitive reactance ndizofanana Kusowa. Chithunzi 7 chikuwonetsa mgwirizano pakati pa mtengo wa Q ndi mafupipafupi a NR4018T220M, ndipo chiyanjanocho chili mu mawonekedwe a belu lotembenuzidwa.

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Chithunzi 7. Ubale pakati pa Q mtengo ndi mafupipafupi a Taiyo Yuden inductor NR4018T220M

Mu bandi ya pafupipafupi yogwiritsira ntchito inductance, kukwezeka kwa mtengo wa Q, kumakhala bwinoko; zikutanthauza kuti machitidwe ake ndi aakulu kwambiri kuposa kukana kwa AC. Nthawi zambiri, mtengo wabwino kwambiri wa Q uli pamwamba pa 40, zomwe zikutanthauza kuti mtundu wa inductor ndi wabwino. Komabe, nthawi zambiri kukondera kwa DC kukuchulukirachulukira, mtengo wa inductance udzachepa ndipo mtengo wa Q nawonso utsika. Ngati waya wosanjikiza kapena waya wa enameled wamitundu yambiri amagwiritsidwa ntchito, mawonekedwe a khungu, ndiye kuti, kukana kwa AC, kumatha kuchepetsedwa, ndipo mtengo wa Q wa inductor ukhoza kuwonjezeka.

Kukaniza kwa DC DCR nthawi zambiri kumawonedwa ngati kukana kwa DC kwa waya wamkuwa, ndipo kukana kumatha kuwerengedwa molingana ndi m'mimba mwake ndi kutalika kwa waya. Komabe, ambiri otsika a SMD inductors adzagwiritsa ntchito kuwotcherera akupanga kuti apange pepala lamkuwa la SMD pamalo omangika. Komabe, chifukwa waya wamkuwa siutali wautali komanso kukana kwake sikokwera, kukana kuwotcherera nthawi zambiri kumabweretsa gawo lalikulu la kukana konse kwa DC. Kutengera TDK's wire-bala SMD inductor CLF6045NIT-1R5N mwachitsanzo, kuyeza kwa DC kukana ndi 14.6mΩ, ndipo kukana kwa DC kumawerengeredwa kutengera kukula kwa waya ndi kutalika ndi 12.1mΩ. Zotsatira zikuwonetsa kuti kukana kuwotcherera kumeneku kumakhala pafupifupi 17% ya kukana konse kwa DC.

AC kukana ACR imakhala ndi khungu komanso kuyandikira, zomwe zimapangitsa kuti ACR ichuluke pafupipafupi; pogwiritsira ntchito inductance general, chifukwa chigawo cha AC ndi chochepa kwambiri kuposa gawo la DC, chikoka choyambitsidwa ndi ACR sichidziwika; koma pa katundu wopepuka, Chifukwa gawo la DC lachepetsedwa, kutayika komwe kumachitika chifukwa cha ACR sikunganyalanyazidwe. Zotsatira za khungu zikutanthauza kuti pansi pazikhalidwe za AC, kugawa komweko mkati mwa woyendetsa sikuli kofanana ndipo kumakhazikika pamwamba pa waya, zomwe zimapangitsa kuchepa kwa gawo lofanana ndi waya, zomwe zimawonjezera kukana kofanana kwa waya ndi pafupipafupi. Kuonjezera apo, mu mawotchi a waya, mawaya oyandikana nawo amachititsa kuwonjezera ndi kuchotsa maginito a maginito chifukwa cha panopa, kotero kuti panopa imakhazikika pamtunda pafupi ndi waya (kapena kutali kwambiri, malingana ndi momwe magetsi akuyendera panopa. ), zomwe zimachititsanso kuti waya wofanana. Chodabwitsa kuti dera limachepa ndipo kukana kofanana kumawonjezeka ndi zomwe zimatchedwa kuyandikira; mu inductance ntchito ya multilayer mapiringidzo, kuyandikira zotsatira ndi zoonekeratu kwambiri.

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Chithunzi 8 chikuwonetsa mgwirizano pakati pa kukana kwa AC ndi ma frequency a waya-bala SMD inductor NR4018T220M. Pafupipafupi 1kHz, kukana kuli pafupifupi 360mΩ; pa 100kHz, kukana kumakwera mpaka 775mΩ; pa 10MHz, mtengo wokana uli pafupi ndi 160Ω. Poyerekeza kutayika kwa mkuwa, kuwerengera kuyenera kuganizira za ACR yoyambitsidwa ndi khungu ndi kuyandikira kwapafupi, ndikusintha kukhala formula (3).

4. Saturation current (ISAT)

Machulukidwe apano a ISAT nthawi zambiri amakhala kukondera komwe kumazindikirika pomwe mtengo wa inductance utsitsidwa monga 10%, 30%, kapena 40%. Kwa ferrite ya mpweya, chifukwa machulukitsidwe ake panopa ndi mofulumira kwambiri, palibe kusiyana kwambiri pakati pa 10% ndi 40%. Onani Chithunzi 4. Komabe, ngati ndi chitsulo chachitsulo chachitsulo (monga choyimitsa stamped), curve ya saturation imakhala yofewa, monga momwe tawonetsera pa Chithunzi 9, kukondera pa 10% kapena 40% ya inductance attenuation ndi zambiri. zosiyana, kotero machulukitsidwe amtengo wapatali adzakambidwa padera pamitundu iwiri yazitsulo zachitsulo motere.

Kwa ferrite yodutsa mpweya, ndizomveka kugwiritsa ntchito ISAT ngati malire apamwamba a inductors pakali pano pakugwiritsa ntchito dera. Komabe, ngati ndi chitsulo cha ufa wachitsulo, chifukwa cha khalidwe la kuchulukitsitsa pang'onopang'ono, sipadzakhala vuto ngakhale kuchuluka kwaposachedwa kwa dera logwiritsira ntchito kupitirira ISAT. Chifukwa chake, chikhalidwe chachitsulo ichi ndi choyenera kwambiri pakusintha ma converter. Pansi pa katundu wolemetsa, ngakhale kuti mtengo wa inductance wa inductance ndi wochepa, monga momwe tawonetsera pa Chithunzi 9, zomwe zikuchitika panopa ndi zapamwamba, koma kulekerera kwamakono kwa capacitor kuli kwakukulu, kotero sikudzakhala vuto. Pansi pa katundu wopepuka, mtengo wa inductance wa inductance ndi wokulirapo, womwe umathandizira kuchepetsa kuthamanga kwaposachedwa kwa inductor, potero kuchepetsa kutayika kwachitsulo. Chithunzi 9 chikufanizira mayendedwe apano a TDK's bala ferrite SLF7055T1R5N ndi stamped iron powder core inductor SPM6530T1R5M pansi pa mtengo womwewo wa inductance.

9

Chithunzi 9. Machulukidwe amakono opindika a chilonda cha ferrite ndi chitsulo choponderezedwa cha ufa pansi pa mtengo womwewo wa inductance.

5. Zovoteledwa panopa (IDC)

Mtengo wa IDC ndiwokondera kwa DC pamene kutentha kwa inductor kukwera kufika pa Tr˚C. Zofotokozerazi zikuwonetsanso mtengo wake wokana wa DC RDC pa 20˚C. Malinga ndi kutentha kwa waya wamkuwa ndi pafupifupi 3,930 ppm, kutentha kwa Tr kukakwera, kukana kwake ndi RDC_Tr = RDC (1 + 0.00393Tr), ndipo mphamvu yake ndi PCU = I2DCxRDC. Kutayika kwa mkuwa uku kumatayidwa pamwamba pa inductor, ndipo kukana kwamafuta ΘTH kwa inductor kumatha kuwerengedwa:

(2)

Gulu 2 limatanthawuza pepala la deta la TDK VLS6045EX (6.0 × 6.0 × 4.5mm), ndikuwerengera kukana kwa kutentha pa kutentha kwa 40˚C. Mwachiwonekere, kwa ma inductors a mndandanda womwewo ndi kukula kwake, kuwerengetsera kukana kwa kutentha kumakhala pafupifupi kofanana chifukwa cha malo omwewo omwe amatha kutentha kutentha; mwa kuyankhula kwina, IDC yomwe idavoteledwa pano ya ma inductors osiyanasiyana imatha kuyerekezedwa. Mitundu yosiyanasiyana (maphukusi) a inductors ali ndi kukana kosiyanasiyana kwamafuta. Table 3 ikuyerekeza kukana kwamafuta kwa ma inductors a TDK VLS6045EX (semi-shielded) ndi SPM6530 mndandanda (wopangidwa). Kuchuluka kwa kutentha kwa kutentha, kumapangitsa kuti kutentha kumapangidwe pamene inductance imayenda kupyolera mu katundu wamakono; mwinamwake, wapansi.

(2)

Table 2. Kukana kwamafuta kwa VLS6045EX mndandanda wa inductors pa kutentha kwa 40˚C

Zitha kuwoneka kuchokera ku Table 3 kuti ngakhale kukula kwa inductors kuli kofanana, kukana kwa kutentha kwa ma inductors osindikizira kumakhala kochepa, ndiko kuti, kutentha kwa kutentha kuli bwino.

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Table 3. Kuyerekeza kukana kutentha kwa ma inductors osiyanasiyana a phukusi.

6. Kutayika kwakukulu

Kutayika kwapakati, komwe kumatchedwa kutayika kwachitsulo, kumayamba chifukwa cha kutayika kwa eddy panopa komanso kutayika kwa hysteresis. Kukula kwa kutayika kwa eddy panopa makamaka kumadalira ngati mfundo yaikulu ndi yosavuta "kuchita"; ngati conductivity ili pamwamba, ndiye kuti, resistivity ndi yochepa, kutayika kwamakono kwa eddy kuli kwakukulu, ndipo ngati resistivity ya ferrite ndi yapamwamba, kuwonongeka kwa eddy panopa kumakhala kochepa. Kutayika kwamakono kwa Eddy kumagwirizananso ndi pafupipafupi. Kukwera kwafupipafupi, kumapangitsanso kutaya kwamakono kwa eddy. Chifukwa chake, zinthu zapakatikati zidzatsimikizira kuchuluka kwa magwiridwe antchito apakati. Nthawi zambiri, pafupipafupi chitsulo ufa pachimake akhoza kufika 1MHz, ndi pafupipafupi ntchito ferrite kufika 10MHz. Ngati ma frequency ogwiritsira ntchito akupitilira ma frequency awa, kutayika kwapano kwa eddy kumawonjezeka mwachangu ndipo kutentha kwachitsulo kumawonjezekanso. Komabe, ndikukula msanga kwa zida zapakati pachitsulo, zitsulo zachitsulo zokhala ndi ma frequency okwera ziyenera kukhala pafupi ndi ngodya.

Kutayika kwina kwachitsulo ndi kutayika kwa hysteresis, komwe kuli kofanana ndi malo otsekedwa ndi phokoso la hysteresis, lomwe limagwirizana ndi kugwedezeka kwa chigawo cha AC chamakono; kugwedezeka kwakukulu kwa AC, kumapangitsanso kutaya kwa hysteresis.

Mu gawo lofanana la inductor, chopinga cholumikizidwa molumikizana ndi chowongolera chimagwiritsidwa ntchito kuwonetsa kutayika kwachitsulo. Mafupipafupi akakhala ofanana ndi SRF, mayendedwe a inductive ndi capacitive reactance amazimitsa, ndipo momwemonso zimakhalira ziro. Panthawiyi, kusokonezeka kwa inductor kumakhala kofanana ndi kukana kwachitsulo chopanda chitsulo mu mndandanda ndi kukana kwachitsulo, ndipo kukana kwachitsulo kumakhala kwakukulu kwambiri kuposa kukana kwazitsulo, kotero The impedance pa SRF pafupifupi yofanana ndi kukana kwachitsulo. Kutengera chitsanzo cha low-voltage inductor, kukana kwake kwachitsulo kumakhala pafupifupi 20kΩ. Ngati mphamvu yamagetsi yamtengo wapatali pamapeto onse awiri a inductor ikuyerekeza kuti ndi 5V, kutaya kwake kwachitsulo kumakhala pafupifupi 1.25mW, zomwe zimasonyezanso kuti kukana kwachitsulo kukulirakulira, kumakhala bwino.

7. Kapangidwe ka chishango

Mapangidwe a ma inductors a ferrite amaphatikizapo osatetezedwa, otetezedwa ndi maginito glue, ndi otetezedwa, ndipo pali kusiyana kwakukulu kwa mpweya mu iliyonse ya iwo. Mwachiwonekere, kusiyana kwa mpweya kudzakhala ndi kutuluka kwa maginito, ndipo poipa kwambiri, kumasokoneza mabwalo ang'onoang'ono ozungulira, kapena ngati pali maginito pafupi, inductance yake idzasinthidwanso. Mapangidwe ena oyikapo ndi chosindikizira chachitsulo chachitsulo. Popeza palibe mpata mkati mwa inductor ndipo mawonekedwe okhotakhota amakhala olimba, vuto la kutayika kwa maginito ndi laling'ono. Chithunzi 10 ndikugwiritsa ntchito ntchito ya FFT ya RTO 1004 oscilloscope kuyeza kukula kwa maginito otayira pa 3mm pamwamba ndi pambali ya inductor yosindikizidwa. Table 4 imatchula kufananitsa kwa maginito otulutsa ma inductors osiyanasiyana. Zitha kuwoneka kuti ma inductors osatetezedwa ali ndi vuto lalikulu kwambiri la maginito; ma inductors okhala ndi maginito ochepa kwambiri, omwe amawonetsa chitetezo chabwino kwambiri cha maginito. . Kusiyana kwa kukula kwa kutayikira kwa maginito a ma inductors azinthu ziwirizi ndi pafupifupi 14dB, yomwe ili pafupifupi kasanu.

10

Chithunzi 10. Kukula kwa mphamvu ya maginito yotayikira yoyezedwa pa 3mm pamwamba ndi pambali ya inductor yosindikizidwa.

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Table 4. Kuyerekeza kutayikira maginito maginito zosiyanasiyana phukusi dongosolo inductors

8. kugwirizana

M'mapulogalamu ena, nthawi zina pamakhala ma seti angapo a otembenuza a DC pa PCB, omwe nthawi zambiri amakonzedwa pafupi ndi mnzake, ndipo ma inductors awo amakonzedwanso moyandikana. Ngati mumagwiritsa ntchito mtundu wosatetezedwa kapena wotetezedwa ndi maginito glue Inductors akhoza kuphatikizidwa wina ndi mzake kuti apange kusokoneza kwa EMI. Choncho, poyika inductor, tikulimbikitsidwa kuti muyambe kuyika polarity ya inductor poyamba, ndikugwirizanitsa malo oyambira ndi opiringiza a mkati mwa makina opangira magetsi ku magetsi osinthira, monga VSW ya buck converter, komwe ndi kosuntha. Malo otuluka amalumikizidwa ndi capacitor yotulutsa, yomwe ndi malo osasunthika; kupota waya wamkuwa kotero kumapanga mlingo wina wa chitetezo chamagetsi. Mu mawaya makonzedwe a multiplexer, kukonza polarity wa inductance kumathandiza kukonza kukula kwa mutual inductance ndi kupewa zina zosayembekezereka EMI mavuto.

Mapulogalamu:

Mutu wapitawu udakambirana zapakatikati, kapangidwe ka phukusi, ndi mawonekedwe ofunikira amagetsi a inductor. Mutuwu ufotokoza momwe mungasankhire mtengo woyenera wa chosinthira cha buck ndi malingaliro osankha inductor yomwe ikupezeka pamalonda.

Monga momwe zasonyezedwera mu equation (5), mtengo wa inductor ndi kusintha kwafupipafupi kwa otembenuza kudzakhudza inductor ripple current (ΔiL). The inductor ripple current idzayenda kudzera mu capacitor yomwe imatulutsa ndikukhudza ma ripple apano a capacitor yotulutsa. Chifukwa chake, zidzakhudza kusankha kwa capacitor yotulutsa ndikuwonjezeranso kukula kwa mphamvu yamagetsi. Komanso, mtengo wa inductance ndi mtengo wa capacitance wotulutsa udzakhudzanso malingaliro a dongosolo ndi kuyankha kwamphamvu kwa katundu. Kusankha mtengo wokulirapo kulibe kupsinjika kwakanthawi kochepa pa capacitor, komanso kumapindulitsa kuchepetsa kutulutsa kwamagetsi ndipo kumatha kusunga mphamvu zambiri. Komabe, mtengo wokulirapo wa inductance ukuwonetsa kuchuluka kwakukulu, ndiko kuti, mtengo wokwera. Choncho, popanga chosinthira, mapangidwe a mtengo wa inductance ndi ofunika kwambiri.

(5)

Zitha kuwoneka kuchokera ku chilinganizo (5) kuti pamene kusiyana pakati pa voteji yolowera ndi mphamvu yotulutsa ndi yayikulu, inductor ripple current idzakhala yokulirapo, yomwe ndizovuta kwambiri pamapangidwe a inductor. Kuphatikizidwa ndi kusanthula kwina kwa inductive, malo opangira ma inductance a chosinthira chotsika nthawi zambiri amayenera kusankhidwa malinga ndi kuchuluka kwa voliyumu yolowera ndi katundu wathunthu.

Popanga mtengo wa inductance, m'pofunika kupanga malonda pakati pa inductor ripple current ndi inductor size, ndi ripple current factor (ripple current factor; γ) imatanthauzidwa apa, monga mu formula (6).

(6)

Kuyika chilinganizo (6) mu chilinganizo (5), mtengo wa inductance ukhoza kufotokozedwa ngati chilinganizo (7).

(7)

Malinga ndi chilinganizo (7), pamene kusiyana pakati pa kulowetsa ndi kutulutsa mphamvu kumakhala kwakukulu, mtengo wa γ ukhoza kusankhidwa waukulu; m'malo mwake, ngati magetsi olowera ndi otuluka ali pafupi, kapangidwe ka mtengo wa γ kuyenera kukhala kocheperako. Kuti musankhe pakati pa chiwongolero chamakono ndi kukula kwake, malinga ndi momwe mumapangidwira, γ nthawi zambiri amakhala 0.2 mpaka 0.5. Zotsatirazi zikutenga RT7276 monga chitsanzo chowonetsera kuwerengera kwa inductance ndi kusankha kwa inductors zomwe zilipo pamalonda.

Design chitsanzo: Zopangidwa ndi RT7276 patsogolo mosalekeza pa nthawi (Advanced Constant On-Time; ACOTTM) synchronous rectification sitepe-pansi Converter, kusintha kwake pafupipafupi ndi 700 kHz, voteji athandizira ndi 4.5V kuti 18V, ndi linanena bungwe voteji ndi 1.05V . Kudzaza kwathunthu ndi 3A. Monga tafotokozera pamwambapa, mtengo wa inductance uyenera kupangidwa molingana ndi kuchuluka kwa voliyumu ya 18V ndi katundu wathunthu wa 3A, mtengo wa γ umatengedwa ngati 0.35, ndipo mtengo womwe uli pamwambapa umasinthidwa kukhala equation (7), inductance. mtengo ndi

Gwiritsani ntchito inductor yokhala ndi mtengo wamba wa 1.5 µH. Njira yoloweza m'malo (5) kuti muwerengere mphamvu ya inductor motere.

Chifukwa chake, nsonga yapamwamba ya inductor ndi

Ndipo mtengo wogwira ntchito wa inductor current (IRMS) ndi

Chifukwa chigawo cha inductor ripple ndi chaching'ono, mtengo wogwira ntchito wa inductor panopa ndi gawo lake la DC, ndipo mtengo wogwira ntchitowu umagwiritsidwa ntchito ngati maziko posankha IDC yomwe idavotera panopa. Ndi mapangidwe a 80% ochepetsa (derating), zofunikira za inductance ndi:

L = 1.5 µH (100 kHz), IDC = 3.77 A, ISAT = 4.34 A

Table 5 imatchula ma inductors omwe alipo amitundu yosiyanasiyana ya TDK, ofanana kukula koma mosiyana ndi phukusi. Zitha kuwoneka kuchokera patebulo kuti machulukidwe apano ndi ovotera a inductor stamped (SPM6530T-1R5M) ndi akulu, ndipo kukana kwamafuta kumakhala kochepa komanso kutulutsa kutentha kuli bwino. Kuphatikiza apo, molingana ndi zomwe takambirana m'mutu wapitawu, zida zapakati pa inductor yosindikizidwa ndi chitsulo cha ufa, motero zimafaniziridwa ndi ma inductors otetezedwa (VLS6045EX-1R5N) otetezedwa (SLF7055T-1R5N) ndi maginito glue. , Ali ndi mawonekedwe abwino a DC kukondera. Chithunzi 11 chikuwonetsa kufananitsa bwino kwa ma inductors osiyanasiyana omwe amagwiritsidwa ntchito ku RT7276 yotsogola yanthawi zonse yosinthira masinthidwe otsika. Zotsatira zikuwonetsa kuti kusiyana koyenera pakati pa atatuwa sikofunikira. Ngati mumaganizira za kutentha kwa kutentha, mawonekedwe a DC kukondera ndi nkhani za magnetic field dissipation, tikulimbikitsidwa kugwiritsa ntchito ma inductors a SPM6530T-1R5M.

(5)

Table 5. Kuyerekeza kwa inductances osiyanasiyana mndandanda wa TDK

11

Chithunzi 11. Kuyerekeza kwa otembenuza bwino ndi ma inductors osiyanasiyana

Mukasankha phukusi lomwelo ndi mtengo wa inductance, koma ma inductors ang'onoang'ono, monga SPM4015T-1R5M (4.4 × 4.1 × 1.5mm), ngakhale kukula kwake kuli kochepa, koma DC kukana RDC (44.5mΩ) ndi kukana kutentha ΘTH ( 51˚C) /W) Chachikulu. Kwa otembenuza azomwezo, mtengo wogwira ntchito wamakono womwe umaloledwa ndi inductor umakhalanso womwewo. Mwachiwonekere, kukana kwa DC kudzachepetsa magwiridwe antchito pansi pa katundu wolemetsa. Kuonjezera apo, kukana kwakukulu kwa kutentha kumatanthawuza kutaya kutentha kosauka. Choncho, posankha inductor, sikoyenera kuganizira za ubwino wochepetsera kukula, komanso kuyesa zofooka zake.

Pomaliza

Inductance ndi imodzi mwazinthu zomwe zimagwiritsidwa ntchito kwambiri posintha ma converter amagetsi, omwe amatha kugwiritsidwa ntchito posungira mphamvu ndikusefa. Komabe, pamapangidwe ozungulira, sikuti mtengo wa inductance womwe uyenera kutsatiridwa, koma magawo ena kuphatikiza kukana kwa AC ndi mtengo wa Q, kulolerana kwapano, kuchulukitsitsa kwachitsulo, ndi kapangidwe ka phukusi, ndi zina zonse, ndizoyenera. kuganiziridwa posankha inductor. . Zosinthazi nthawi zambiri zimagwirizana ndi zinthu zapakati, njira zopangira, kukula ndi mtengo wake. Chifukwa chake, nkhaniyi ikuwonetsa mawonekedwe amitundu yosiyanasiyana yachitsulo komanso momwe mungasankhire inductance yoyenera ngati kalozera wamapangidwe amagetsi.