litaba

Kakaretso

Li-inductors ke likarolo tsa bohlokoa haholo ho li-converter, joalo ka polokelo ea matla le li-filters tsa matla. Ho na le mefuta e mengata ea li-inductors, joalo ka lits'ebetso tse fapaneng (ho tloha khafetsa ho ea ho maqhubu a phahameng), kapa lisebelisoa tse fapaneng tsa mantlha tse amang litšobotsi tsa inductor, joalo-joalo. Li-inductors tse sebelisoang ho fetola li-converter ke likarolo tse phahameng tsa matla a khoheli. Leha ho le joalo, ka lebaka la lintlha tse fapaneng tse kang lisebelisoa, maemo a ts'ebetso (joalo ka motlakase le hona joale), le mocheso oa tikoloho, litšobotsi le likhopolo tse hlahisoang li fapane haholo. Ka hona, mohahong oa potoloho, ho phaella ho parameter ea motheo ea boleng ba inductance, kamano pakeng tsa ho thibela ho inductor le ho hanyetsa ha AC le maqhubu, tahlehelo ea mantlha le litšobotsi tsa hona joale tsa saturation, joalo-joalo li ntse li lokela ho nkoa. Sengoliloeng sena se tla hlahisa lisebelisoa tse 'maloa tsa bohlokoa tsa inductor le litšobotsi tsa tsona, hape se tataise baenjiniere ba matla ho khetha li-inductors tse fumanehang khoebong.

Selelekela

Inductor ke motsoako oa motlakase oa motlakase, o entsoeng ka ho phunya palo e itseng ea li-coil (coil) holim'a bobbin kapa mokokotlo ka terata e kentsoeng. Khoeli ena e bitsoa khoele ea inductance kapa Inductor. Ho ea ka molao-motheo oa induction ea motlakase, ha coil le matla a khoheli li tsamaisana, kapa coil e hlahisa matla a khoheli a chenchana ka motlakase o mong, ho tla hlahisoa motlakase o kentsoeng ho hanela phetoho ea matla a khoheli a mantlha. 'me tšobotsi ena ea ho thibela phetoho ea hona joale e bitsoa inductance.

Foromo ea boleng ba inductance ke mokhoa oa (1), o leka-lekaneng le ho kenella ha makenete, lisekoere tsa matsoeliko a thinyetsang N, le sebaka se lekanang sa makenete sa potoloho ea karolo ea Ae, 'me e lekana ka tsela e fapaneng le bolelele ba potoloho ea makenete le . Ho na le mefuta e mengata ea inductance, e 'ngoe le e' ngoe e loketse lits'ebetso tse fapaneng; inductance e amana le sebopeho, boholo, mokhoa oa ho tsoelipana, palo ea ho chenchana, le mofuta oa lisebelisoa tsa makenete tse mahareng.

(1)

Ho itšetlehile ka sebōpeho sa mokokotlo oa tšepe, inductance e kenyelletsa toroidal, E core le drum; mabapi le thepa ea mantlha ea tšepe, ho na le mantlha a ceramic le mefuta e 'meli e bonolo ea makenete. Ke ferrite le phofo ea tšepe. Ho ipapisitsoe le sebopeho kapa mokhoa oa ho paka, ho na le leqeba la terata, li-multi-layer, le tse bōpiloeng, 'me leqeba la terata le na le sekoahelo se se nang tšireletso le halofo ea sekhomaretsi sa makenete Se sirelelitsoeng (se sirelelitsoeng ka halofo) le se sirelelitsoeng (se sirelelitsoeng), joalo-joalo.

Inductor e sebetsa joalo ka potoloho e khuts'oane ka kotloloho, 'me e fana ka tšitiso e phahameng ho feto-fetoha ha hona joale. Litšebeliso tsa mantlha lipotolohong li kenyelletsa ho khangoa, ho sefa, ho lokisa, le ho boloka matla. Ts'ebelisong ea switching converter, inductor ke karolo ea bohlokoa ka ho fetesisa ea ho boloka matla, 'me e theha sefahla se tlase se nang le capacitor e hlahisoang ho fokotsa phallo ea motlakase, ka hona e bapala karolo ea bohlokoa ts'ebetsong ea ho sefa.

Sengoliloeng sena se tla hlahisa lisebelisoa tse fapaneng tsa mantlha tsa li-inductors le litšobotsi tsa tsona, hammoho le tse ling tsa litšobotsi tsa motlakase tsa li-inductors, e le tlhahlobo ea bohlokoa ea tlhahlobo ea ho khetha li-inductors nakong ea moralo oa potoloho. Mohlala oa kopo, mokhoa oa ho bala boleng ba inductance le mokhoa oa ho khetha inductor e tloaelehileng e fumanehang khoebong e tla hlahisoa ka mehlala e sebetsang.

Mofuta oa thepa ea mantlha

Li-inductors tse sebelisoang ho fetola li-converter ke likarolo tse phahameng tsa matla a khoheli. Thepa ea mantlha e bohareng e ama haholo litšobotsi tsa inductor, joalo ka impedance le frequency, inductance value le frequency, kapa core saturation. Lintlha tse latelang li tla hlahisa papiso ea lisebelisoa tse 'maloa tse tloaelehileng tsa tšepe le litšoaneleho tsa tsona tsa saturation e le mokhoa oa bohlokoa oa ho khetha li-inductors tsa matla:

1. Moko oa Ceramic

Ceramic Core ke e 'ngoe ea lisebelisoa tse tloaelehileng tsa inductance. Haholo-holo e sebelisetsoa ho fana ka mohaho o tšehetsang o sebelisoang ha ho phunya khola. E boetse e bitsoa "air core inductor". Hobane motheo oa tšepe o sebelisitsoeng ke thepa e seng ea makenete e nang le mocheso o tlase haholo oa mocheso, boleng ba inductance bo tsitsitse haholo mofuteng oa mocheso o sebetsang. Leha ho le joalo, ka lebaka la thepa e seng ea makenete e le ea mahareng, inductance e tlase haholo, e sa lokelang haholo ho sebelisoa ha li-converter tsa matla.

2. Ferrite

Setsi sa ferrite se sebelisoang ka kakaretso li-inductors tse phahameng ke motsoako oa ferrite o nang le nickel zinc (NiZn) kapa manganese zinc (MnZn), e leng thepa e bonolo ea makenete ea ferromagnetic e nang le khatello e tlase. Setšoantšo sa 1 se bontša hysteresis curve (BH loop) ea motsoako o akaretsang oa makenete. Matla a qobelloang a HC a thepa ea khoheli e boetse e bitsoa matla a khoheli, e bolelang hore ha thepa ea khoheli e entsoe ka matla a khoheli, matla a eona a khoheli (magnetization) a fokotsehile ho fihlela ho zero Matla a matla a khoheli a hlokahalang ka nako eo. Koetliso e tlase e bolela khanyetso e tlase ea demagnetization hape e bolela tahlehelo e tlase ea hysteresis.

Manganese-zinki le ferrite ea nickel-zinki e na le matla a phahameng a ho hema (μr), a ka bang 1500-15000 le 100-1000, ka ho latellana. Ho kenella ha tsona ho matla ha makenete ho etsa hore mokokotlo oa tšepe o phahame ka molumo o itseng. The inductance. Leha ho le joalo, bothata ke hore matla a eona a mamellehang a saturation a tlase, 'me hang ha tšepe e se e tletse, matla a khoheli a tla theoha haholo. Sheba Setšoantšo sa 4 bakeng sa mokhoa o ntseng o fokotseha oa matla a khoheli a ferrite le li-cores tsa tšepe tse phofo ha mokokotlo oa tšepe o tletse. Papiso. Ha e sebelisoa ho li-inductors tsa matla, lekhalo la moea le tla sala sebakeng se seholo sa makenete, se ka fokotsang ho phunyeletsa, ho qoba ho tlala le ho boloka matla a mangata; ha lekhalo la moea le kenyelelitsoe, tekano e lekanang le kamano e ka ba 20- Pakeng tsa 200. Kaha ho hanyetsa ho phahameng ha thepa ka boeona ho ka fokotsa tahlehelo e bakoang ke eddy ea hona joale, tahlehelo e tlaase ho maqhubu a phahameng, 'me e loketse haholoanyane li-transformer tsa maqhubu a phahameng, li-inductors tsa EMI le li-inductors tsa polokelo ea matla tsa li-converter tsa matla. Mabapi le maqhubu a ts'ebetso, nickel-zinc ferrite e loketse ho sebelisoa (> 1 MHz), ha manganese-zinc ferrite e loketse lihlopha tse tlaase tsa maqhubu (<2 MHz).

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Setšoantšo sa 1. Mokokotlo oa hysteresis oa motsoako oa makenete (BR: remanence; BSAT: saturation magnetic flux density)

3. Mokotla oa tšepe oa phofo

Li-cores tsa tšepe tsa phofo le tsona ke lisebelisoa tse bonolo tsa ferromagnetic. Li entsoe ka li-alloys tsa phofo ea tšepe ea lisebelisoa tse fapaneng kapa phofo ea tšepe feela. Foromo e na le lisebelisoa tse seng tsa makenete tse nang le boholo bo fapaneng ba likaroloana, kahoo curve ea saturation e batla e le bonolo. Mokotla oa tšepe hangata o na le toroidal. Setšoantšo sa 2 se bonts'a motsoako oa tšepe oa phofo le pono ea eona e fapaneng.

Li-cores tse tloaelehileng tsa tšepe tse nang le phofshoana li kenyelletsa tšepe-nickel-molybdenum alloy (MPP), sendust (Sendust), tšepe-nickel alloy (high flux) le tšepe ea phofo ea tšepe (phofo ea tšepe). Ka lebaka la likarolo tse fapaneng, litšobotsi tsa eona le litheko li boetse li fapane, tse amang khetho ea li-inductors. Lintlha tse latelang li tla hlahisa mefuta ea mantlha e boletsoeng ka holimo le ho bapisa litšobotsi tsa bona:

A. Tšepe ea tšepe-nickel-molybdenum (MPP)

Fe-Ni-Mo alloy e khutsufalitsoe joalo ka MPP, e leng khutsufatso ea phofo ea molypermalloy. Tekanyetso e lekanyelitsoeng e ka ba 14-500, 'me matla a khoheli a matla a khoheli a ka ba 7500 Gauss (Gauss), e phahameng ho feta matla a khoheli a matla a ferrite (hoo e ka bang 4000-5000 Gauss). Ba bangata ba tsoa. MPP e na le tahlehelo e nyane ka ho fetisisa ea tšepe 'me e na le botsitso bo botle ba mocheso har'a li-cores tsa phofo. Ha motlakase oa kantle oa DC o fihla ho ISAT ea saturation, boleng ba inductance bo fokotseha butle ntle le ho fokotseha ka tšohanyetso. MPP e na le ts'ebetso e ntle empa e theko e phahameng, 'me hangata e sebelisoa e le inductor ea matla le EMI filtering bakeng sa li-converter tsa matla.

B. Sendust

The iron-silicon-aluminium alloy iron core ke motsoako oa tšepe oa alloy o entsoeng ka tšepe, silicon, le aluminium, e nang le matla a matla a khoheli a ka bang 26 ho ea ho 125. Tahlehelo ea tšepe e pakeng tsa motsoako oa tšepe le MPP le tšepe ea tšepe ea nickel alloy. . The saturation magnetic flux density e phahame ho feta MPP, e ka bang 10500 Gauss. Ho tsitsisa ha mocheso le litšoaneleho tsa hona joale tsa saturation li tlase hanyane ho feta MPP le alloy ea tšepe-nickel, empa e molemo ho feta tšepe ea tšepe ea mantlha le mokokotlo oa ferrite, 'me litšenyehelo tse lekanyelitsoeng li theko e tlaase ho feta MPP le tšepe-nickel alloy. E sebelisoa haholo ho EMI filtering, power factor correction (PFC) le li-inductors tsa matla a ho fetola li-converter tsa matla.

C. Alloy ea tšepe ea nickel (high flux)

Mokotla oa tšepe-nickel alloy o entsoe ka tšepe le nickel. Matla a matla a khoheli a ka bang 14-200. Tahlehelo ea tšepe le botsitso ba mocheso li pakeng tsa MPP le tšepe-silicon-aluminium alloy. Mokotla oa tšepe-nickel alloy o na le matla a phahameng ka ho fetisisa a matla a khoheli, a ka bang 15,000 Gauss, 'me o khona ho mamella maqhubu a phahameng a DC a bias,' me litšobotsi tsa eona tsa DC leeme le tsona li betere. Sekhahla sa ts'ebeliso: Tokiso ea matla a sebetsang, inductance ea polokelo ea matla, inductance ea filthara, sefetoleli se phahameng sa frequency ea flyback converter, jj.

D. Phofo ya tshepe

Mokotla oa tšepe oa tšepe o entsoe ka likaroloana tse phahameng tsa tšepe tse hloekileng tse nang le likaroloana tse nyenyane haholo tse sirelelitsoeng ho tloha ho tse ling. Ts'ebetso ea tlhahiso e etsa hore e be le lekhalo la moea le ajoang. Ntle le sebopeho sa selikalikoe, libopeho tse tloaelehileng tsa phofo ea tšepe li boetse li na le mefuta ea E-mofuta le litempe. Ho kenella ha matla a khoheli a karolo ea tšepe e ka bang 10 ho isa ho 75, 'me boima bo phahameng ba matla a khoheli bo ka ba 15000 Gauss. Har'a li-cores tsa tšepe tsa phofo, motsoako oa tšepe o na le tahlehelo e phahameng ka ho fetisisa ea tšepe empa theko e tlase haholo.

Setšoantšo sa 3 se bontša BH curves ea PC47 manganese-zinc ferrite e entsoeng ke TDK le li-cores tsa tšepe tse phofshoana -52 le -2 tse entsoeng ke MICROMETALS; tekano ea matla a khoheli ea manganese-zinc ferrite e phahame haholo ho feta ea li-cores tsa tšepe tse phofshoana 'me e tletse The magnetic flux density e boetse e fapane haholo, ferrite e ka bang 5000 Gauss le motsoako oa tšepe oa tšepe o feta 10000 Gauss.

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Setšoantšo sa 3. BH curve ea manganese-zinc ferrite le li-cores tsa phofo ea tšepe ea lisebelisoa tse fapaneng.

Ka kakaretso, litšobotsi tsa saturation tsa mantlha tsa tšepe li fapane; hang ha matla a saturation a fetisoa, matla a khoheli a motlakase a ferrite a tla theoha haholo, athe motsoako oa tšepe o ka fokotseha butle-butle. Setšoantšo sa 4 se bonts'a litšobotsi tsa ho theoha ha makenete tsa phofshoana ea tšepe e nang le matla a matla a khoheli a tšoanang le ferrite e nang le lekhalo la moea tlas'a matla a fapaneng a matla a khoheli. Sena se boetse se hlalosa ho kenngoa ha mokokotlo oa ferrite, hobane ho phunyeletsa ho theoha haholo ha motheo o tletse, joalokaha ho ka bonoa ho tloha ho equation (1), e boetse e etsa hore inductance e theohe ka matla; ha motsoako oa phofo o nang le lekhalo la moea o ajoang, matla a khoheli Tekanyo e fokotseha butle ha motheo oa tšepe o tletse, kahoo inductance e fokotseha ka bonolo, ke hore, e na le litšobotsi tse ntle tsa DC leeme. Tšebelisong ea li-converter tsa matla, tšobotsi ena e bohlokoa haholo; haeba tšobotsi ea ho phalla butle-butle ea inductor e se e ntle, motlakase oa motlakase o nyolohela ho saturation hona joale, 'me ho theoha ha tšohanyetso ho tla etsa hore khatello ea hona joale ea kristale e fetohang e phahame haholo, e leng bonolo ho baka tšenyo.

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Setšoantšo sa 4. Magnetic permeability drop character of the powder iron core le ferrite iron core e nang le lekhalo la moea tlas'a matla a fapaneng a matla a khoheli.

Litšobotsi tsa motlakase oa inductor le sebopeho sa sephutheloana

Ha o rala switching converter le ho khetha inductor, boleng ba inductance L, impedance Z, AC resistance ACR le Q value (quality factor), e lekantsoe IDC ea hajoale le ISAT, le tahlehelo ea mantlha (tahlehelo ea mantlha) le litšobotsi tse ling tsa bohlokoa tsa motlakase kaofela li tlameha ho etsoa. nahanela. Ntle le moo, sebopeho sa liphutheloana sa inductor se tla ama boholo ba ho lutla ha makenete, e leng se amang EMI. Lintlha tse latelang li tla tšohla litšobotsi tse boletsoeng ka holimo ka thoko e le lintlha tsa ho khetha li-inductors.

1. Boleng ba inductance (L)

Boleng ba inductance ba inductor ke parameter ea bohlokoa ka ho fetisisa moralong oa potoloho, empa e tlameha ho hlahlojoa hore na boleng ba inductance bo tsitsitse ho frequency ea ts'ebetso. Boleng ba lebitso la inductance hangata bo lekantsoe ho 100 kHz kapa 1 MHz ntle le leeme la kantle la DC. Le ho etsa bonnete ba hore ho na le monyetla oa ho hlahisa lihlahisoa tse ngata, mamello ea inductor hangata ke ± 20% (M) le ± 30% (N). Setšoantšo sa 5 ke graph ea inductance-frequency character ya Taiyo Yuden inductor NR4018T220M e lekantsoeng ka Wayne Kerr's LCR meter. Joalokaha ho bontšitsoe setšoantšong, sekhahla sa boleng ba inductance se batla se bataletse pele ho 5 MHz, 'me boleng ba inductance bo ka nkoa e le ntho e sa fetoheng. Ka sehlopha se phahameng sa maqhubu ka lebaka la resonance e hlahisoang ke capacitance ea parasitic le inductance, boleng ba inductance bo tla eketseha. Maqhubu ana a resonance a bitsoa "self-resonant frequency" (SRF), eo hangata e hlokang ho ba holimo haholo ho feta maqhubu a ts'ebetso.

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Setšoantšo sa 5, Taiyo Yuden NR4018T220M setšoantšo sa tekanyo ea sebopeho sa inductance-frequency

2. Tšitiso (Z)

Joalokaha ho bontšitsoe setšoantšong sa 6, setšoantšo sa impedance se ka boela sa bonoa ho tloha ts'ebetsong ea inductance ka maqhubu a fapaneng. The impedance ea inductor e batla e lekana le frequency (Z=2πfL), kahoo ha lebelo le phahame, karabelo e tla ba kholo haholo ho feta khanyetso ea AC, kahoo impedance e itšoara joalo ka inductance e hloekileng (mohato ke 90˚). Ka maqhubu a phahameng, ka lebaka la phello ea capacitance ea parasitic, sebaka sa "self-resonant frequency point of impedance" se ka bonoa. Ka mor'a ntlha ena, impedance e theoha 'me e fetoha capacitive,' me mohato o fetoha butle-butle ho -90 ˚.

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3. Boleng ba Q le khanyetso ea AC (ACR)

Q boleng tlhalosong ea inductance ke karo-karolelano ea karabelo ho hanyetsa, ke hore, karo-karolelano ea karolo e inahaneloang ho karolo ea 'nete ea impedance, joalo ka foromo (2).

(2)

Moo XL e leng karabelo ea inductor, 'me RL ke khanyetso ea AC ea inductor.

Boemong bo fokolang ba maqhubu, khanyetso ea AC e kholo ho feta karabelo e bakoang ke inductance, kahoo boleng ba eona ba Q bo tlaase haholo; ha maqhubu a ntse a eketseha, ts'ebetso (e ka bang 2πfL) e ba kholoanyane le e kholoanyane, esita le haeba ho hanyetsa ka lebaka la phello ea letlalo (phello ea letlalo) le phello e haufi (proximity) phello e ba e kholoanyane le e kholoanyane, 'me boleng ba Q bo ntse bo eketseha ka makhetlo a mangata. ; ha e atamela SRF, reactance inductive butle-butle e fokotsoa ke capacitive reactance, 'me boleng ba Q butle-butle bo fokotseha; ha SRF e fetoha zero, hobane inductive reactance le capacitive reactance li ts'oana ka ho felletseng. Setšoantšo sa 7 se bontša kamano pakeng tsa boleng ba Q le makhetlo a mangata a NR4018T220M, 'me kamano e ka sebōpeho sa tšepe e khelohileng.

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Setšoantšo sa 7. Kamano pakeng tsa boleng ba Q le makhetlo a mangata a Taiyo Yuden inductor NR4018T220M

Sehlopheng sa maqhubu a kopo ea inductance, boleng bo phahameng ba Q, bo betere; ho bolela hore karabelo ea eona e kholo ho feta khanyetso ea AC. Ka kakaretso, boleng bo botle ba Q bo ka holimo ho 40, ho bolelang hore boleng ba inductor bo botle. Leha ho le joalo, ka kakaretso ha leeme la DC le ntse le eketseha, boleng ba inductance bo tla fokotseha mme boleng ba Q le bona bo tla fokotseha. Haeba ho sebelisoa terata e sephara ea enameled kapa terata e nang le mefuta e mengata, phello ea letlalo, ke hore, ho hanyetsa AC, e ka fokotsoa, ​​​​'me boleng ba Q ba inductor le bona bo ka eketseha.

The DC resistance DCR ka kakaretso e nkuoa e le khanyetso ea DC ea terata ea koporo, 'me khanyetso e ka baloa ho latela bophara ba terata le bolelele. Leha ho le joalo, boholo ba li-inductors tse tlase tsa hona joale tsa SMD li tla sebelisa ultrasonic welding ho etsa letlapa la koporo la SMD setsing sa matsoeli. Leha ho le joalo, hobane terata ea koporo ha e telele ka bolelele 'me boleng ba ho hanyetsa ha bo phahame, ho hanyetsa ha li-welding hangata ho ikarabella bakeng sa karolo e kholo ea khanyetso ea DC. Ho nka mohlala oa TDK oa leqeba la SMD CLF6045NIT-1R5N, tekanyo e lekantsoeng ea DC ke 14.6mΩ, 'me khanyetso ea DC e baloa ho latela bophara ba terata le bolelele ba 12.1mΩ. Liphetho li bonts'a hore khanyetso ena ea welding e etsa hoo e ka bang 17% ea khanyetso ea DC ka kakaretso.

Khanyetso ea AC ACR e na le phello ea letlalo le phello e haufi, e tla etsa hore ACR e eketsehe khafetsa; ts'ebetsong ea inductance e akaretsang, hobane karolo ea AC e tlase haholo ho feta karolo ea DC, tšusumetso e bakoang ke ACR ha e totobetse; empa ka mojaro o bobebe, Hobane karolo ea DC e fokotsehile, tahlehelo e bakoang ke ACR e ke ke ea hlokomolohuoa. Phello ea letlalo e bolela hore tlas'a maemo a AC, kabo ea hona joale ka hare ho mokhanni ha e lekane 'me e tsepamisitsoe holim'a terata, e leng se bakang phokotso ea sebaka se lekanang sa terata, e leng se eketsang khanyetso e lekanang ea terata. makhetlo a mangata. Ho phaella moo, ka terata e pota-potileng, lithapo tse haufi li tla etsa hore ho eketsoe le ho tlosoa ha matla a khoheli ka lebaka la hona joale, e le hore hona joale ho tsepamise maikutlo holim'a terata (kapa sebaka se hōle ka ho fetisisa, ho itšetlehile ka tataiso ea hona joale. ), e boetse e baka terata e lekanang. Ketsahalo ea hore sebaka se fokotseha 'me khanyetso e lekanang e eketseha ke seo ho thoeng ke phello e haufi; ts'ebetsong ea inductance ea multilayer winding, phello e haufi e totobetse le ho feta.

8

Setšoantšo sa 8 se bontša kamano pakeng tsa khanyetso ea AC le makhetlo a mangata a terata-leqeba la SMD inductor NR4018T220M. Ka makhetlo a 1kHz, khanyetso e ka bang 360mΩ; ho 100kHz, khanyetso e nyolohela ho 775mΩ; ho 10MHz, boleng ba ho hanyetsa bo haufi le 160Ω. Ha ho hakanngoa tahlehelo ea koporo, palo e tlameha ho nahana ka ACR e bakoang ke letlalo le liphello tse haufi, le ho e fetola ho foromo (3).

4. Saturation current (ISAT)

Saturation ea hajoale ISAT hangata ke leeme la hajoale le tšoailoeng ha boleng ba inductance bo fokotsoa joalo ka 10%, 30%, kapa 40%. Bakeng sa ferrite ea lekhalo la moea, hobane tšobotsi ea hona joale ea saturation e potlakile haholo, ha ho na phapang e ngata pakeng tsa 10% le 40%. Sheba Setšoantšo sa 4. Leha ho le joalo, haeba e le mokokotlo oa phofo ea tšepe (e kang inductor e entsoeng ka setempe), sekhahla sa saturation se batla se le bonolo, joalokaha ho bontšitsoe setšoantšong sa 9, leeme la hona joale ho 10% kapa 40% ea ho fokotsa ho fokotsa ho fokotseha ho hongata. e fapaneng, kahoo boleng ba hona joale ba saturation bo tla tšohloa ka thoko bakeng sa mefuta e 'meli ea li-cores tsa tšepe ka tsela e latelang.

Bakeng sa ferrite ea lekhalo la moea, hoa utloahala ho sebelisa ISAT joalo ka moeli o kaholimo oa li-inductor tsa hajoale bakeng sa lits'ebetso tsa potoloho. Leha ho le joalo, haeba e le motsoako oa phofo ea tšepe, ka lebaka la tšobotsi ea ho phalla butle, ho ke ke ha e-ba le bothata le haeba boholo ba hona joale ba potoloho ea kopo bo feta ISAT. Ka hona, tšobotsi ena ea mantlha ea tšepe e loketse haholo bakeng sa ho fetola lits'ebetso tsa converter. Tlas'a mojaro o boima, le hoja boleng ba inductance ba inductor bo le tlase, joalokaha ho bontšitsoe setšoantšong sa 9, sekhahla sa hona joale sa ripple se phahame, empa mamello ea hona joale ea capacitor e phahame, kahoo e ke ke ea e-ba bothata. Tlas'a mojaro o bobebe, boleng ba inductance ba inductor bo kholoanyane, bo thusang ho fokotsa maqhubu a ripple a inductor, ka hona ho fokotsa tahlehelo ea tšepe. Setšoantšo sa 9 se bapisa lekhalo la hona joale la saturation ea TDK's leqeba ferrite SLF7055T1R5N le setempe sa tšepe core inductor SPM6530T1R5M tlas'a boleng bo tšoanang ba lebitso la inductance.

9

Setšoantšo sa9

5. E lekantsoe hajoale (IDC)

Boleng ba IDC ke khetho ea DC ha mocheso oa inductor o nyolohela ho Tr˚C. Litlhaloso li boetse li bonts'a boleng ba eona ba khanyetso ea DC RDC ho 20˚C. Ho ea ka mocheso oa mocheso oa mohala oa koporo o ka bang 3,930 ppm, ha mocheso oa Tr o phahama, boleng ba eona ba ho hanyetsa ke RDC_Tr = RDC (1 + 0.00393Tr), 'me matla a eona ke PCU = I2DCxRDC. Tahlehelo ena ea koporo e qhaloa ka holim'a inductor, 'me khanyetso ea mocheso ΘTH ea inductor e ka baloa:

(2)

Letlapa la 2 le bua ka leqephe la data la letoto la TDK VLS6045EX (6.0×6.0×4.5mm), mme le lekanya ho hanyetsa mocheso ka ho phahama ha mocheso oa 40˚C. Ho totobetse hore bakeng sa li-inductors tsa letoto le boholo bo tšoanang, ho hanyetsa mocheso o baloang ho batla ho tšoana ka lebaka la sebaka se le seng sa ho senya mocheso; ka mantsoe a mang, ho ka hakanyetsoa hore na IDC ea hajoale ea li-inductors tse fapaneng. Letoto le fapaneng (liphutheloana) tsa li-inductors li na le likhanyetso tse fapaneng tsa mocheso. Letlapa la 3 le bapisa ho hanyetsa mocheso oa li-inductors tsa TDK VLS6045EX series (semi-shielded) le SPM6530 series (molded). E kholoanyane ho hanyetsa mocheso, ho phahama ha mocheso o phahameng o hlahisoang ha inductance e phalla ka mojaro oa hona joale; ho seng joalo, e ka tlaase.

(2)

Letlapa la 2. Ho hanyetsa mocheso oa li-inductors tsa VLS6045EX ka ho phahama ha mocheso oa 40˚C.

E ka bonoa ho Lethathamo la 3 hore le haeba boholo ba li-inductors bo tšoana, ho hanyetsa mocheso oa li-inductors tse entsoeng ka setempe ho tlaase, ke hore, ho senya mocheso ho molemo.

(3)

Letlapa la 3. Papiso ea ho hanyetsa mocheso oa li-inductors tse fapaneng tsa liphutheloana.

6. Tahlehelo ea mantlha

Tahlehelo ea mantlha, eo ho thoeng ke tahlehelo ea tšepe, e bakoa haholo ke tahlehelo ea hona joale ea eddy le tahlehelo ea hysteresis. Boholo ba tahlehelo ea hona joale ea eddy haholo-holo bo itšetlehile ka hore na thepa ea motheo e bonolo ho "tsamaisa"; haeba conductivity e phahame, ke hore, resistivity e tlaase, tahlehelo ea hona joale ea eddy e phahame, 'me haeba resistivity ea ferrite e phahame, tahlehelo ea hona joale ea eddy e batla e le tlaase. Eddy tahlehelo ea hona joale e boetse e amana le makhetlo a mangata. Ha makhetlo a mangata a phahame, tahlehelo ea hona joale ea eddy e kholoanyane. Ka hona, lisebelisoa tsa mantlha li tla tseba hore na lebelo le nepahetseng la ts'ebetso ea mantlha ke efe. Ka kakaretso, lebelo la ts'ebetso ea tšepe ea tšepe ea mantlha e ka fihla ho 1MHz, 'me maqhubu a sebetsang a ferrite a ka fihla ho 10MHz. Haeba ts'ebetso ea ts'ebetso e feta khafetsa ena, tahlehelo ea hona joale ea eddy e tla eketseha ka potlako 'me mocheso oa tšepe o tla boela o eketsehe. Leha ho le joalo, ka nts'etsopele e potlakileng ea lisebelisoa tsa mantlha tsa tšepe, li-cores tsa tšepe tse nang le maqhubu a phahameng a ts'ebetso li lokela ho ba haufi le sekhutlo.

Tahlehelo e 'ngoe ea tšepe ke tahlehelo ea hysteresis, e lekanang le sebaka se koaletsoeng ke hysteresis curve, e amanang le maqhubu a maqhubu a karolo ea AC ea hona joale; ha AC swing e kholoanyane, tahlehelo e kholo ea hysteresis.

Potolohong e lekanang ea inductor, mohanyetsi o hokahaneng ka ho bapa le inductor hangata o sebelisoa ho hlalosa tahlehelo ea tšepe. Ha frequency e lekana le SRF, inductive reactance le capacitive reactance e hlakola, 'me karabelo e ts'oanang ke zero. Ka nako ena, impedance ea inductor e lekana le ho hanyetsa tahlehelo ea tšepe ka letoto le nang le ho hanyetsa mapheo, 'me ho hanyetsa tahlehelo ea tšepe e kholoanyane ho feta ho hanyetsa maqhubu, kahoo The impedance ho SRF e batla e lekana le ho hanyetsa tahlehelo ea tšepe. Ho nka mohlala oa inductor ea matla a tlase, khanyetso ea eona ea tahlehelo ea tšepe e ka ba 20kΩ. Haeba matla a motlakase a sebetsang lipheletsong tse peli tsa inductor a hakanngoa hore ke 5V, tahlehelo ea tšepe ea eona e ka ba 1.25mW, e leng se bontšang hore ho hanyetsa ho lahleheloa ke tšepe ho molemo ho feta.

7. Sebopeho sa thebe

Sebopeho sa liphutheloana tsa li-inductors tsa ferrite li kenyelletsa tse sa sirelelitsoeng, tse sirelelitsoeng ka sekhomaretsi sa makenete, le tse sirelelitsoeng, 'me ho na le lekhalo le leholo ho e' ngoe ea tsona. Ho totobetse hore lekhalo la moea le tla ba le phallo ea makenete, 'me boemong bo bobe ka ho fetisisa, le tla kena-kenana le lipotoloho tse nyenyane tse potolohileng, kapa haeba ho na le thepa ea makenete e haufi, inductance ea eona e tla fetoloa. Sebopeho se seng sa liphutheloana ke setempe sa phofo ea tšepe e tekiloeng. Kaha ha ho na lekhalo ka hare ho inductor le sebopeho sa mapheo se tiile, bothata ba ho senya matla a khoheli bo batla bo le nyane. Setšoantšo sa 10 ke tšebeliso ea mosebetsi oa FFT oa RTO 1004 oscilloscope ho lekanya boholo ba matla a khoheli a lutlang ho 3mm ka holimo le ka lehlakoreng la inductor e hatisitsoeng. Letlapa la 4 le thathamisa papiso ea matla a khoheli a lutlang a li-inductors tse fapaneng tsa sebopeho sa sephutheloana. Ho ka bonoa hore li-inductors tse se nang tšireletso li na le ho lutla ho hoholo ha makenete; li-inductors tse nang le setempe li na le ho lutla ho honyane ha makenete, ho bonts'a phello e ntlehali ea tšireletso. . Phapang ka boholo ba matla a khoheli a lutla a li-inductors tsa meaho ena e 'meli e ka ba 14dB, e leng hoo e ka bang makhetlo a 5.

10

Setšoantšo sa 10. Boholo ba matla a khoheli a lutlang a lekantsoeng ho 3mm ka holimo le ka lehlakoreng la inductor e hatisitsoeng.

(4)

Letlapa la 4. Papiso ea ho lutla matla a khoheli a li-inductors tse fapaneng tsa sebopeho sa liphutheloana

8. ho kopanya

Likopong tse ling, ka linako tse ling ho na le li-converter tse ngata tsa DC ho PCB, tseo hangata li hlophisoang haufi le tse ling, 'me li-inductors tsa tsona tse tsamaisanang le tsona li hlophisoa haufi le tse ling. Haeba u sebelisa mofuta o sa sirelelitsoeng kapa o sirelelitsoeng ka halofo o nang le magnetic glue Inductors li ka kopanngoa hammoho ho theha tšitiso ea EMI. Ka hona, ha u beha inductor, ho kgothaletswa hore o tšoaee polarity ea inductor pele, 'me u kopanye ntlha ea ho qala le ea ho phalla ea karolo e ka hare ea inductor ho motlakase oa ho fetola converter, joalo ka VSW ea buck converter, e leng ntlha e sisinyehang. Sebaka sa ho tsoa se hokahane le capacitor e hlahisoang, e leng ntlha e tsitsitseng; terata ea koporo ka hona e etsa tekanyo e itseng ea tšireletso ea tšimo ea motlakase. Ka tlhophiso ea wiring ea multiplexer, ho lokisa polarity ea inductance thusa ho lokisa boholo ba inductance mutual le ho qoba mathata a mang a sa lebelloang a EMI.

Lisebelisoa:

Khaolo e fetileng e buile ka thepa ea mantlha, sebopeho sa sephutheloana, le litšobotsi tsa bohlokoa tsa motlakase tsa inductor. Khaolo ena e tla hlalosa mokhoa oa ho khetha boleng bo nepahetseng ba inductance ba buck converter le mehopolo ea ho khetha inductor e fumanehang khoebong.

Joalokaha ho bontšitsoe ka equation (5), boleng ba inductor le ho fetoha ha maqhubu a converter ho tla ama inductor ripple current (ΔiL). The inductor ripple current e tla phalla ka har'a capacitor e hlahisoang ebe e ama lebelo la hona joale la phallo ea capacitor. Ka hona, e tla ama khetho ea capacitor ea tlhahiso mme e ame le ho feta boholo ba ripple ea motlakase o tsoang. Ho feta moo, boleng ba inductance le boleng ba tlhahiso ea capacitance bo tla boela bo ama tlhahiso ea maikutlo ea tsamaiso le karabelo e matla ea mojaro. Ho khetha boleng bo boholo ba inductance ho na le khatello e tlase ea hajoale ho capacitor, hape ho molemo ho fokotsa ripple ea motlakase mme ho ka boloka matla a mangata. Leha ho le joalo, boleng bo boholo ba inductance bo bontša molumo o moholo, ke hore, theko e phahameng. Ka hona, ha ho etsoa converter, moralo oa boleng ba inductance o bohlokoa haholo.

(5)

E ka bonoa ho tsoa ho formula (5) hore ha lekhalo pakeng tsa motlakase oa ho kenya letsoho le motlakase oa tlhahiso e le kholoanyane, motlakase oa motlakase oa motlakase o tla ba moholo, e leng boemo bo bobe ka ho fetisisa ba moralo oa inductor. Ha e kopantsoe le tlhahlobo e 'ngoe ea inductive, sebaka sa moralo oa inductance oa sesebelisoa se theohang hangata se lokela ho khethoa tlas'a maemo a matla a ho kenya matla le mojaro o felletseng.

Ha ho etsoa moralo oa boleng ba inductance, hoa hlokahala ho etsa khoebo pakeng tsa motlakase oa motlakase oa motlakase le boholo ba inductor, 'me ntlha ea hona joale ea ripple (ripple current factor; γ) e hlalosoa mona, joalo ka foromo (6).

(6)

Ho fetola foromo (6) ho foromo (5), boleng ba inductance bo ka hlalosoa e le foromo (7).

(7)

Ho ea ka foromo (7), ha phapang pakeng tsa motlakase oa ho kenya le ho tsoa e le kholoanyane, boleng ba γ bo ka khethoa bo boholo; ho fapana le hoo, haeba motlakase oa ho kenya le ho tsoa o haufi, moralo oa boleng ba γ o tlameha ho ba o monyenyane. E le hore u khethe pakeng tsa motlakase oa motlakase oa motlakase le boholo, ho latela boleng ba phihlelo ea moralo oa setso, γ hangata ke 0.2 ho ea ho 0.5. Se latelang se nka RT7276 e le mohlala ho bontša lipalo tsa inductance le khetho ea li-inductors tse fumanehang khoebong.

Mohlala oa moralo: E entsoe ka RT7276 e tsoetseng pele ka nako (Advanced Constant On-Time; ACOTTM) synchronous rectification step-down converter, switching frequency ea eona ke 700 kHz, motlakase oa ho kenya ke 4.5V ho 18V, 'me motlakase o tsoang ke 1.05V . Nako ea mojaro o felletseng ke 3A. Joalokaha ho boletsoe ka holimo, boleng ba inductance bo tlameha ho etsoa tlas'a maemo a matla a phahameng a ho kenya letsoho a 18V le mojaro o feletseng oa 3A, boleng ba γ bo nkoa e le 0.35, 'me boleng bo ka holimo bo nkeloa sebaka ke equation (7), inductance. boleng ke

Sebelisa inductor e nang le boleng bo tloaelehileng ba lebitso la 1.5 µH. Phapanyetsano ea foromo (5) ho bala maqhubu a ripple a inductor ka tsela e latelang.

Ka hona, tlhōrō ea hona joale ea inductor ke

Le boleng bo sebetsang ba inductor current (IRMS) ke

Hobane karolo ea inductor ripple e nyane, boleng bo sebetsang ba hona joale ba inductor ke karolo ea eona ea DC, 'me boleng bona bo sebetsang bo sebelisoa e le motheo oa ho khetha IDC e lekantsoeng ea hajoale. Ka moralo oa 80% oa derating (derating), litlhoko tsa inductance ke:

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

Letlapa la 5 le thathamisa li-inductors tse fumanehang tsa letoto le fapaneng la TDK, le tšoanang ka boholo empa le fapane ka sebopeho sa sephutheloana. E ka bonoa ho tloha tafoleng hore saturation ea hona joale le e lekantsoeng hona joale ea inductor e entsoeng ka setempe (SPM6530T-1R5M) e kholo, 'me ho hanyetsa mocheso ho nyenyane' me mocheso oa mocheso o molemo. Ho phaella moo, ho ea ka puisano e khaolong e fetileng, lisebelisoa tsa mantlha tsa inductor e entsoeng ka setempe ke motsoako oa phofo ea tšepe, kahoo e bapisoa le mokokotlo oa ferrite oa semi-shielded (VLS6045EX-1R5N) le li-inductors tse sirelelitsoeng (SLF7055T-1R5N). ka sekhomaretsi sa makenete. , E na le litšobotsi tse ntle tsa DC leeme. Setšoantšo sa 11 se bonts'a papiso e sebetsang ea li-inductors tse fapaneng tse sebelisitsoeng ho RT7276 e tsoetseng pele ka nako e sa fetoheng ea tokiso e tlase. Liphello li bontša hore phapang ea katleho pakeng tsa tse tharo ha e bohlokoa. Haeba u nahana ka ho senya mocheso, litšobotsi tsa DC leeme le litaba tsa ho senya matla a khoheli, ho kgothaletswa ho sebelisa li-inductors tsa SPM6530T-1R5M.

(5)

Letlapa la 5. Papiso ea li-inductance tsa lihlopha tse fapaneng tsa TDK

11

Setšoantšo sa 11. Papiso ea katleho ea converter le li-inductors tse fapaneng

Haeba u khetha sebopeho se tšoanang sa sephutheloana le boleng ba inductance, empa li-inductors tsa boholo bo nyane, joalo ka SPM4015T-1R5M (4.4 × 4.1 × 1.5mm), leha boholo ba eona bo le nyane, empa DC ho hanyetsa RDC (44.5mΩ) le ho hanyetsa mocheso ΘTH ( 51˚C) /W) E kholoanyane. Bakeng sa li-converter tsa litlhaloso tse tšoanang, boleng bo sebetsang ba hona joale bo mamelloang ke inductor bo boetse bo tšoana. Ho hlakile hore ho hanyetsa ha DC ho tla fokotsa katleho tlas'a mojaro o boima. Ho phaella moo, ho hanyetsa mocheso o moholo ho bolela ho futsaneha ha mocheso o futsanehileng. Ka hona, ha u khetha inductor, ha ho hlokahale feela ho nahana ka melemo ea boholo bo fokotsehileng, empa hape le ho hlahloba mefokolo ea eona e tsamaeang le eona.

Ha re phethela

Inductance ke e 'ngoe ea likarolo tse sebelisoang hangata ho fetola li-converter tsa matla, tse ka sebelisetsoang ho boloka matla le ho sefa. Leha ho le joalo, moralong oa potoloho, ha se boleng ba inductance feela bo hlokang ho eloa hloko, empa litekanyo tse ling tse kenyelletsang khanyetso ea AC le boleng ba Q, mamello ea hajoale, ts'ebetso ea mantlha ea tšepe, le sebopeho sa sephutheloana, joalo-joalo, kaofela ke litekanyo tse lokelang ho etsoa. ho nahanoa ha u khetha inductor. . Litekanyetso tsena hangata li amana le thepa ea mantlha, ts'ebetso ea tlhahiso, boholo le litšenyehelo. Ka hona, sengoloa sena se hlahisa litšobotsi tsa lisebelisoa tse fapaneng tsa mantlha tsa tšepe le mokhoa oa ho khetha inductance e nepahetseng e le sesupo sa moralo oa phepelo ea motlakase.