labarai

Takaitawa

Inductor suna da mahimmancin abubuwa masu mahimmanci a cikin masu canzawa, kamar ajiyar makamashi da masu tace wuta. Akwai nau'ikan inductor iri-iri, kamar na aikace-aikace daban-daban (daga ƙarancin mitar mita zuwa babban mitar), ko maɓalli daban-daban waɗanda ke shafar halayen inductor, da sauransu. Inductor da aka yi amfani da su wajen sauya masu canzawa su ne manyan abubuwan maganadisu masu yawan gaske. Koyaya, saboda dalilai daban-daban kamar kayan aiki, yanayin aiki (kamar ƙarfin lantarki da na yanzu), da zafin yanayi, halaye da ra'ayoyin da aka gabatar sun bambanta sosai. Sabili da haka, a cikin ƙirar kewaye, ban da ma'auni na asali na ƙimar inductance, dangantakar da ke tsakanin impedance na inductor da juriya na AC da mita, hasara mai mahimmanci da halayen halin yanzu, da dai sauransu dole ne a yi la'akari da su. Wannan labarin zai gabatar da mahimman kayan inductor da yawa da halayensu, da kuma jagorantar injiniyoyin wutar lantarki don zaɓar madaidaitan inductor na kasuwanci.

Gabatarwa

Inductor wani abu ne na shigar da wutar lantarki na lantarki, wanda aka samo shi ta hanyar jujjuya takamaiman adadin coils (coil) akan bobbin ko cibiya tare da keɓaɓɓen waya. Ana kiran wannan coil inductance coil ko Inductor. Dangane da ka'idar shigar da wutar lantarki, lokacin da na'ura da filin maganadisu ke motsawa dangane da juna, ko kuma na'urar ta haifar da canjin yanayin maganadisu ta hanyar madaidaicin halin yanzu, za a samar da wutar lantarki da aka jawo don tsayayya da canjin filin maganadisu na asali. kuma wannan sifa ta hana canjin halin yanzu ana kiranta inductance.

Tsarin darajar inductance shine tsari (1), wanda yayi daidai da karfin maganadisu, murabba'in iskar ya juya N, da kuma daidaitaccen wurin da'irar Magnetic kewayen yanki Ae, kuma yana da inversely gwargwado zuwa daidai tsayin da'ira na Magnetic le. . Akwai nau'ikan inductance da yawa, kowannensu ya dace da aikace-aikace daban-daban; inductance yana da alaƙa da siffa, girman, hanyar iska, adadin juyi, da nau'in kayan magnetic matsakaici.

(1)

Dangane da siffar ƙarfe na ƙarfe, inductance ya haɗa da toroidal, E core da drum; dangane da kayan aikin ƙarfe, akwai galibin yumbu da nau'in maganadisu mai laushi guda biyu. Su ne ferrite da ƙarfe foda. Dangane da tsari ko hanyar marufi, akwai raunin waya, Multi-Layer, da gyare-gyare, kuma raunin waya yana da mara kariya da rabin Magnetic glue Garkuwa (wani garkuwa) da garkuwa (garkuwa), da sauransu.

Inductor yana aiki kamar gajeriyar da'ira a halin yanzu kai tsaye, kuma yana ba da babban cikas ga musanya halin yanzu. Abubuwan amfani na yau da kullun a cikin da'irori sun haɗa da shaƙewa, tacewa, daidaitawa, da ajiyar kuzari. A cikin aikace-aikacen na'urar canzawa, inductor shine mafi mahimmancin bangaren ajiyar makamashi, kuma yana samar da matattara mai ƙarancin wucewa tare da capacitor na fitarwa don rage ƙarfin fitarwa, don haka yana taka muhimmiyar rawa a aikin tacewa.

Wannan labarin zai gabatar da nau'ikan kayan mahimmanci na inductor da halayensu, da kuma wasu halaye na lantarki na inductor, a matsayin muhimmin ma'anar kimantawa don zaɓar inductor yayin ƙirar kewaye. A cikin misalin aikace-aikacen, yadda za a ƙididdige ƙimar inductance da yadda za a zaɓi madaidaicin inductor na kasuwanci za a gabatar da shi ta hanyar misalai masu amfani.

Nau'in kayan masarufi

Inductor da aka yi amfani da su wajen sauya masu canzawa su ne manyan abubuwan maganadisu masu yawan gaske. Babban abu a tsakiya ya fi rinjayar halayen inductor, kamar impedance da mita, ƙimar inductance da mitar, ko halayen jikewa na asali. Masu zuwa za su gabatar da kwatancen kayan ƙarfe na yau da kullun na yau da kullun da halayen jikewar su azaman mahimman tunani don zaɓar inductor:

1. Ceramic core

Ceramic core yana ɗaya daga cikin kayan inductance gama gari. Ana amfani da shi musamman don samar da tsarin tallafi da ake amfani da shi lokacin jujjuya coil. Ana kuma kiransa "air core inductor". Saboda tushen baƙin ƙarfe da aka yi amfani da shi abu ne wanda ba na maganadisu ba tare da ƙarancin zafin jiki, ƙimar inductance tana da ƙarfi sosai a cikin kewayon zafin aiki. Duk da haka, saboda kayan da ba na maganadisu ba a matsayin matsakaici, inductance yana da ƙananan ƙananan, wanda bai dace da aikace-aikacen masu canza wutar lantarki ba.

2. Ferrite

Babban jigon ferrite da ake amfani da shi a cikin inductor mai girma gabaɗaya wani fili ne na ferrite mai ɗauke da nickel zinc (NiZn) ko zinc na manganese (MnZn), wanda shine abu mai laushi na Magnetic ferromagnetic tare da ƙaramin ƙarfi. Hoto na 1 yana nuna madaidaicin jijiyoyi (BH madauki) na babban abin maganadisu. Ƙarfin tilasa HC na kayan maganadisu kuma ana kiransa karfi da ƙarfi, wanda ke nufin cewa lokacin da kayan maganadisu suka yi maganadisu zuwa saturation na maganadisu, magnetization (magnetization) ya ragu zuwa sifili Ƙarfin magnetic da ake buƙata a lokacin. Ƙananan tilastawa yana nufin ƙananan juriya ga demagnetization kuma yana nufin ƙananan asarar hysteresis.

Manganese-zinc da nickel-zinc ferrite suna da ingantacciyar ƙarancin dangi (μr), kusan 1500-15000 da 100-1000, bi da bi. Babban ƙarfin maganadisu yana sa babban ƙarfen ƙarfe ya fi girma a cikin wani ƙarar. Inductance. Duk da haka, rashin amfani shi ne cewa jikewar saturation na halin yanzu yana da ƙasa kaɗan, kuma da zarar ainihin ƙarfe ya cika, ƙarfin maganadisu zai ragu sosai. Koma zuwa Hoto na 4 don raguwar yanayin ƙarfin maganadisu na ferrite da foda na ƙarfe yayin da baƙin ƙarfe ya cika. Kwatanta. Lokacin da aka yi amfani da su a cikin inductor na wutar lantarki, za a bar ratar iska a cikin babban da'irar maganadisu, wanda zai iya rage haɓaka, guje wa jikewa da adana ƙarin kuzari; lokacin da ratawar iska ta haɗa, daidaitattun ƙayyadaddun dangi na iya zama kusan 20- Tsakanin 200. Tun da babban tsayayyar kayan da kanta zai iya rage asarar da aka yi ta hanyar eddy halin yanzu, asarar yana da ƙananan ƙananan ƙananan, kuma ya fi dacewa da shi. manyan masu canza wuta, EMI tace inductor da inductor ajiyar makamashi na masu canza wuta. Dangane da mitar aiki, nickel-zinc ferrite ya dace don amfani (> 1 MHz), yayin da manganese-zinc ferrite ya dace da ƙananan ƙananan mitoci (<2 MHz).

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Hoto 1. Ƙaƙwalwar ƙwanƙwasa na magnetic core (BR: remanence; BSAT: saturation magnetic flux density)

3. Foda baƙin ƙarfe core

Foda baƙin ƙarfe cores kuma taushi-magnetic ferromagnetic kayan. An yi su ne da ƙarfe foda na kayan aiki daban-daban ko foda na ƙarfe kawai. Dabarar ta ƙunshi kayan da ba na maganadisu ba tare da girman barbashi daban-daban, don haka madaidaicin madaidaicin yana da ɗan laushi. Baƙin ƙarfe na foda galibi toroidal ne. Hoto na 2 yana nuna asalin ƙarfe na foda da ra'ayi na giciye.

Ƙwayoyin ƙarfe na yau da kullun sun haɗa da ƙarfe-nickel-molybdenum gami (MPP), sendust (Sendust), ƙarfe-nickel gami (high flux) da baƙin ƙarfe foda (ƙarfe foda). Saboda sassa daban-daban, halayensa da farashinsa kuma sun bambanta, wanda ke shafar zaɓin inductor. Masu zuwa za su gabatar da nau'ikan asali da aka ambata kuma su kwatanta halayensu:

A. Iron-nickel-molybdenum gami (MPP)

Fe-Ni-Mo alloy an rage shi azaman MPP, wanda shine taƙaitaccen foda na molypermalloy. Matsakaicin dangi shine kusan 14-500, kuma jikewar motsin maganadisu shine kusan Gauss 7500 (Gauss), wanda ya fi girma girma na ferrite (kimanin 4000-5000 Gauss). Yawancin fita. MPP yana da mafi ƙarancin asarar ƙarfe kuma yana da mafi kyawun kwanciyar hankali a tsakanin ƙoshin ƙarfe na foda. Lokacin da na waje DC halin yanzu ya kai jikewa na yanzu ISAT, da inductance darajar rage a hankali ba tare da kwatsam attenuation. MPP yana da mafi kyawun aiki amma farashi mai girma, kuma yawanci ana amfani dashi azaman inductor da kuma tace EMI don masu canza wuta.

B. Sendust

Iron-silicon-aluminum alloy baƙin ƙarfe core shine ƙarfe na ƙarfe wanda ya ƙunshi baƙin ƙarfe, silicon, da aluminum, tare da ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun magnetic na kusan 26 zuwa 125. Rashin baƙin ƙarfe yana tsakanin ƙarfe foda da MPP da baƙin ƙarfe-nickel gami. . Matsakaicin yawan ƙarfin maganadisu ya fi MPP girma, kusan 10500 Gauss. Kwanciyar zafin jiki da halayen halin yanzu sun ɗan ƙasa kaɗan zuwa MPP da ƙarfe-nickel gami, amma mafi kyawun ƙarfe foda da ferrite core, kuma farashin dangi yana da rahusa fiye da MPP da ƙarfe-nickel gami. Ana amfani da shi mafi yawa a cikin tacewa EMI, da'irori na gyaran wutar lantarki (PFC) da inductor na masu canza wuta.

C. Iron-nickel gami (high flux)

Bakin ƙarfe-nickel na baƙin ƙarfe an yi shi da ƙarfe da nickel. Matsakaicin ƙarfin maganadisu na dangi shine kusan 14-200. Rashin baƙin ƙarfe da kwanciyar hankali na zafin jiki suna tsakanin MPP da baƙin ƙarfe-silicon-aluminum gami. Ƙarfin-nickel alloy core yana da mafi girman saturation na maganadisu na maganadisu, kusan 15,000 Gauss, kuma yana iya jure maɗaukakin raƙuman ruwa na DC, kuma halayensa na DC sun fi kyau. Ƙimar aikace-aikacen: Gyara abubuwa masu aiki da ƙarfi, inductance ajiyar makamashi, inductance tace, babban mitar mai sauya juzu'i, da sauransu.

D. Iron foda

Bakin foda na baƙin ƙarfe an yi shi ne da ɓangarorin ƙarfe mai tsafta tare da ƙananan barbashi waɗanda aka keɓe daga juna. Tsarin masana'antu ya sa ya sami rarraba iska. Baya ga siffar zobe, nau'in foda na baƙin ƙarfe na kowa yana da nau'in E-type da nau'in stamping. Matsakaicin ƙarfin maganadisu na ƙwanƙwasa foda na ƙarfe yana kusan 10 zuwa 75, kuma babban jikewa na ƙarfin maganadisu yana kusan 15000 Gauss. Daga cikin nau'ikan ƙarfe na foda, ƙwanƙolin ƙarfe na ƙarfe yana da asarar ƙarfe mafi girma amma mafi ƙarancin farashi.

Hoto na 3 yana nuna madaidaicin BH na PC47 manganese-zinc ferrite wanda TDK ke ƙera da ƙoshin baƙin ƙarfe -52 da -2 wanda MICROMETALS ke ƙera; Dangantakar yanayin maganadisu na manganese-zinc ferrite ya fi na foda na baƙin ƙarfe kuma yana da cikakken ƙarfin ƙarfin maganadisu shima ya bambanta sosai, ferrite yana kusan 5000 Gauss kuma babban foda na ƙarfe ya fi 10000 Gauss.

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Hoto 3. BH curve na manganese-zinc ferrite da baƙin ƙarfe foda na kayan daban-daban

A taƙaice, halayen jikewa na ƙarfe na ƙarfe sun bambanta; da zarar an wuce saturation halin yanzu, ƙarfin maganadisu na ferrite core zai ragu sosai, yayin da ɗigon foda na baƙin ƙarfe zai iya raguwa a hankali. Hoto na 4 yana nuna halayen jujjuyawar ƙarfin maganadisu na asalin ƙarfe na foda mai ƙarfin maganadisu iri ɗaya da ferrite tare da tazarar iska ƙarƙashin mabanbantan ƙarfin filin maganadisu. Wannan kuma yana bayyana inductance na ferrite core, saboda magudanar ruwa yana faɗuwa sosai a lokacin da jigon ya cika, kamar yadda ake iya gani daga lissafin (1), hakanan yana sa inductance ɗin ta ragu sosai; yayin da foda core tare da rarraba iska rata, da Magnetic permeability The kudi rage a hankali a lokacin da baƙin ƙarfe core ne cikakken, don haka inductance rage a hankali, wato, yana da mafi kyau DC son zuciya halaye. A cikin aikace-aikacen masu canza wutar lantarki, wannan sifa tana da matukar muhimmanci; idan jinkirin jikewar halayen inductor ba shi da kyau, inductor na yanzu yana tashi zuwa jikewar halin yanzu, kuma raguwar inductance kwatsam zai haifar da damuwa na yau da kullun na kristal mai canzawa ya tashi sosai, wanda ke da sauƙin haifar da lalacewa.

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Hoto 4. Magnetic permeability drop halaye na foda baƙin ƙarfe core da ferrite baƙin ƙarfe core tare da iska ratar karkashin daban-daban Magnetic filin ƙarfi.

Inductor halayen lantarki da tsarin kunshin

Lokacin zayyana mai canzawa da zaɓin inductor, ƙimar inductance L, impedance Z, AC juriya ACR da ƙimar Q (ƙimar inganci), IDC na yanzu da ISAT da aka ƙididdige su, da babban hasara (asara ta asali) da sauran mahimman halayen lantarki duk dole ne. a yi la'akari. Bugu da ƙari, tsarin marufi na inductor zai yi tasiri ga girman leak ɗin maganadisu, wanda hakan ya shafi EMI. Masu zuwa za su tattauna halayen da aka ambata a sama daban a matsayin la'akari don zaɓar inductor.

1. Ƙimar Inductance (L)

Ƙimar inductance na inductor ita ce mafi mahimmancin ma'auni na asali a ƙirar da'ira, amma dole ne a bincika ko ƙimar inductance ta tsaya tsayin daka a mitar aiki. Ƙimar ƙimar inductance yawanci ana aunawa a 100 kHz ko 1 MHz ba tare da son zuciya na DC na waje ba. Kuma don tabbatar da yuwuwar samarwa ta atomatik yawan jama'a, haƙurin inductor yawanci ± 20% (M) da ± 30% (N). Hoto na 5 shine jadawali siffa mai mitar inductance na Taiyo Yuden inductor NR4018T220M wanda aka auna tare da mitar LCR na Wayne Kerr. Kamar yadda aka nuna a cikin adadi, madaidaicin ƙimar inductance yana da ɗan lebur kafin 5 MHz, kuma ƙimar inductance kusan ana iya ɗaukar shi azaman dindindin. A cikin babban mitar band saboda resonance da parasitic capacitance da inductance ke haifar, ƙimar inductance zata ƙaru. Wannan mitar resonance ana kiranta mitar mai ɗaukar kai (SRF), wanda yawanci yana buƙatar ya zama mafi girma fiye da mitar aiki.

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Hoto 5, Taiyo Yuden NR4018T220M inductance- mitar siffa mai ma'aunin ma'auni

2. Tashin hankali (Z)

Kamar yadda aka nuna a hoto na 6, ana kuma iya ganin zanen impedance daga aikin inductance a mitoci daban-daban. Ƙunƙarar inductor yana kusan daidai da mitar (Z=2πfL), don haka mafi girman mitar, amsawar zai fi girma fiye da juriya na AC, don haka impedance yayi kama da inductance mai tsabta (lokaci shine 90˚). A maɗaukaki masu girma, saboda tasirin ƙarfin ƙarfi na parasitic, ana iya ganin ma'anar mitar da kai na impedance. Bayan wannan batu, impedance ya sauke kuma ya zama capacitive, kuma lokaci a hankali yana canzawa zuwa -90 ˚.

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3. Q darajar da AC juriya (ACR)

Q darajar a cikin ma'anar inductance shine rabon amsawa ga juriya, wato, rabon ɓangaren tunanin zuwa ainihin ɓangaren impedance, kamar yadda a cikin tsari (2).

(2)

Inda XL shine reactance na inductor, kuma RL shine juriyar AC na inductor.

A cikin ƙananan kewayon mitar, ƙarfin AC ya fi girma fiye da amsawar da inductance ya haifar, don haka ƙimar Q ɗinsa ba ta da yawa; yayin da mitar ta karu, reactance (kusan 2πfL) ya zama mafi girma kuma ya fi girma, ko da juriya saboda tasirin fata (tasirin fata) da kusanci (kusanci) tasirin tasirin yana girma da girma, kuma ƙimar Q har yanzu yana ƙaruwa tare da mita. ; lokacin da yake gabatowa SRF, reactance na inductive yana raguwa a hankali ta hanyar amsawar capacitive, kuma ƙimar Q a hankali ya zama ƙarami; lokacin da SRF ya zama sifili, saboda inductive reactance da capacitive reactance gaba daya bace. Hoto na 7 yana nuna alaƙar da ke tsakanin ƙimar Q da mitar NR4018T220M, kuma dangantakar tana cikin siffar kararrawa da aka juyar da ita.

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Hoto 7. Alakar da ke tsakanin ƙimar Q da mitar Taiyo Yuden inductor NR4018T220M

A cikin rukunin mitar aikace-aikacen inductance, mafi girman ƙimar Q, mafi kyau; yana nufin cewa amsawar sa ya fi ƙarfin AC. Gabaɗaya magana, mafi kyawun ƙimar Q yana sama da 40, wanda ke nufin cewa ingancin inductor yana da kyau. Koyaya, gabaɗaya yayin da son rai na DC ya ƙaru, ƙimar inductance zata ragu kuma ƙimar Q zata ragu. Idan aka yi amfani da wayar enamel mai lebur ko kuma wayoyi da aka yi wa nau'in iri-iri, za a iya rage tasirin fata, wato, juriyar AC, kuma ana iya ƙara ƙimar Q na inductor.

Juriya na DC DCR gabaɗaya ana ɗaukarsa juriyar DC na wayar jan ƙarfe, kuma ana iya ƙididdige juriyar gwargwadon diamita da tsayin waya. Koyaya, yawancin ƙananan inductor na SMD na yanzu za su yi amfani da waldi na ultrasonic don yin takardar jan karfe na SMD a tashar iska. Duk da haka, saboda wayar jan ƙarfe ba ta da tsayi kuma ƙimar juriya ba ta da girma, juriya na walda sau da yawa yana yin adadi mai yawa na juriyar DC gabaɗaya. Ɗaukar TDK ta waya-rauni SMD inductor CLF6045NIT-1R5N a matsayin misali, auna DC juriya ne 14.6mΩ, da DC juriya lissafta dangane da waya diamita da tsawon ne 12.1mΩ. Sakamakon ya nuna cewa wannan juriya na walda ya kai kusan kashi 17% na juriyar DC gabaɗaya.

AC juriya ACR yana da tasirin fata da tasirin kusanci, wanda zai haifar da ACR ya karu tare da mita; a cikin aikace-aikacen inductance na gabaɗaya, saboda ɓangaren AC ya fi ƙasa da bangaren DC, tasirin da ACR ya haifar ba a bayyane yake ba; amma a nauyi mai sauƙi, Saboda an rage bangaren DC, asarar da ACR ta haifar ba za a iya watsi da ita ba. Tasirin fata yana nufin cewa a ƙarƙashin yanayin AC, rarrabawar yanzu a cikin mai gudanarwa ba daidai ba ne kuma yana mai da hankali kan saman wayar, wanda ya haifar da raguwa a cikin yanki mai tsaka-tsakin waya daidai, wanda hakan yana ƙara ƙarfin juriya na waya tare da shi. mita. Bugu da kari, a cikin jujjuyawar waya, wayoyi da ke kusa da su za su haifar da kari da raguwar filayen maganadisu saboda halin da ake ciki, ta yadda na yanzu ya ta'allaka ne a saman da ke kusa da wayar (ko kuma saman mafi nisa, dangane da alkiblar halin yanzu). ), wanda kuma ke haifar da tsangwama daidai gwargwado. Lamarin da yankin ke raguwa kuma daidaitaccen juriya yana ƙaruwa shine abin da ake kira tasirin kusanci; a cikin aikace-aikacen inductance na iska mai yawa, tasirin kusanci ya fi bayyana.

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Hoto 8 yana nuna alakar da ke tsakanin juriyar AC da mitar waya-rauni SMD inductor NR4018T220M. A mitar 1kHz, juriya yana kusan 360mΩ; a 100kHz, juriya ya tashi zuwa 775mΩ; a 10MHz, ƙimar juriya tana kusa da 160Ω. Lokacin ƙididdige asarar jan ƙarfe, lissafin dole ne yayi la'akari da ACR da fata ke haifar da tasirin kusanci, kuma a canza shi zuwa tsari (3).

4. Saturation current (ISAT)

Saturation na yanzu ISAT gabaɗaya shine alamar son rai a halin yanzu lokacin da aka rage ƙimar inductance kamar 10%, 30%, ko 40%. Ga ferrite ta tazara, saboda yanayin saturation na yanzu yana da sauri sosai, babu bambanci sosai tsakanin 10% da 40%. Koma zuwa Hoto 4. Duk da haka, idan yana da mahimmancin foda na baƙin ƙarfe (kamar inductor mai hatimi), madaidaicin saturation yana da ɗan laushi, kamar yadda aka nuna a cikin Hoto 9, halin yanzu a 10% ko 40% na inductance attenuation yana da yawa. daban-daban, don haka jikewar darajar halin yanzu za a tattauna daban don nau'ikan nau'ikan nau'ikan ƙarfe guda biyu kamar haka.

Don ferrite ta tazarar iska, yana da kyau a yi amfani da ISAT a matsayin babban iyaka mafi girman inductor na yanzu don aikace-aikacen kewayawa. Duk da haka, idan yana da baƙin ƙarfe foda core, saboda jinkirin jikewa halayyar, ba za a sami matsala ko da matsakaicin halin yanzu na aikace-aikace da'irar ya wuce ISAT. Saboda haka, wannan sifa mai mahimmancin ƙarfe ya fi dacewa don sauya aikace-aikacen masu canzawa. Ƙarƙashin nauyi mai nauyi, kodayake ƙimar inductance na inductor yana da ƙasa, kamar yadda aka nuna a cikin Hoto na 9, ƙimar ripple na yanzu yana da girma, amma haƙurin capacitor na yanzu yana da girma, don haka ba zai zama matsala ba. Ƙarƙashin nauyi mai sauƙi, ƙimar inductance na inductor ya fi girma, wanda ke taimakawa wajen rage raguwa na inductor, don haka rage asarar ƙarfe. Hoto 9 yayi kwatanta jikewar lanƙwan halin yanzu na TDK's rauni ferrite SLF7055T1R5N da hatimin ƙarfe foda core inductor SPM6530T1R5M ƙarƙashin ƙimar ƙima iri ɗaya na inductance.

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Hoto 9. Saturation na halin yanzu na rauni ferrite da hatimin baƙin ƙarfe core a ƙarƙashin ƙimar ƙima ɗaya na inductance

5. Rated halin yanzu (IDC)

Ƙimar IDC ita ce son rai na DC lokacin da zafin inductor ya tashi zuwa Tr˚C. Ƙayyadaddun ƙayyadaddun bayanai kuma suna nuna ƙimar juriya ta DC RDC a 20˚C. Dangane da ma'aunin zafin waya na jan ƙarfe yana kusan 3,930 ppm, lokacin da zafin jiki na Tr ya tashi, ƙimar juriyarsa shine RDC_Tr = RDC (1+0.00393Tr), kuma amfani da wutar lantarki shine PCU = I2DCxRDC. Wannan asarar tagulla tana bazuwa a saman inductor, kuma ana iya ƙididdige juriya na thermal ΘTH na inductor:

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Tebur 2 yana nufin takardar bayanan jerin TDK VLS6045EX (6.0 × 6.0 × 4.5mm), kuma yana ƙididdige juriya na thermal a hawan zafin jiki na 40˚C. Babu shakka, don inductors na jeri iri ɗaya da girman, ƙididdige juriya na thermal kusan iri ɗaya ne saboda yanki ɗaya na zubar da zafi; a wasu kalmomi, ana iya ƙididdige ƙimar IDC na yanzu na inductor daban-daban. Daban-daban jerin (fakitoci) na inductor suna da juriya na thermal daban-daban. Tebu 3 yana kwatanta juriya na thermal na inductors na jerin TDK VLS6045EX (mai garkuwa da juna) da jerin SPM6530 (wanda aka ƙera). Mafi girman juriya na thermal, mafi girman hawan zafin jiki da aka haifar lokacin da inductance ke gudana ta cikin halin yanzu; in ba haka ba, ƙananan.

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Tebur 2. Juriya na thermal na VLS6045EX jerin inductor a yawan zafin jiki na 40˚C

Ana iya gani daga tebur na 3 cewa ko da girman inductor yayi kama da haka, juriya na thermal na inductor da aka buga ya yi ƙasa, wato, zafi mai zafi ya fi kyau.

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Tebur 3. Kwatanta juriya na thermal na inductor fakiti daban-daban.

6. Core hasara

Babban hasara, wanda ake magana da shi azaman asarar ƙarfe, galibi ana haifar da shi ne ta hanyar hasara na yanzu da kuma asarar hysteresis. Girman eddy na yanzu asarar ya dogara ne akan ko ainihin kayan yana da sauƙin "yi"; idan conductivity yana da girma, wato, rashin ƙarfi yana da ƙasa, hasara na eddy yana da girma, kuma idan tsayayyar ferrite ya yi girma, asarar halin yanzu yana da ƙananan ƙananan. Eddy halin yanzu asarar kuma yana da alaƙa da mita. Mafi girman mitar, mafi girman hasara na yanzu. Sabili da haka, ainihin kayan aiki zai ƙayyade daidaitattun mitar aiki na ainihin. Gabaɗaya magana, mitar aiki na ƙarfe foda core na iya kaiwa 1MHz, kuma mitar aiki na ferrite na iya kaiwa 10MHz. Idan mitar aiki ta wuce wannan mitar, hasarar eddy a halin yanzu za ta ƙaru da sauri kuma zafin zafin baƙin ƙarfe shima zai ƙaru. Duk da haka, tare da saurin haɓaka kayan ƙarfe na ƙarfe, ƙananan ƙarfe tare da mafi girman matakan aiki ya kamata su kasance a kusa da kusurwa.

Wani hasara na baƙin ƙarfe shine asarar hysteresis, wanda yayi daidai da yankin da ke kewaye da maƙarƙashiyar hysteresis, wanda ke da alaƙa da girman girman ɓangaren AC na halin yanzu; mafi girma da AC lilo, mafi girma da asarar hysteresis.

A daidai da'irar inductor, ana amfani da resistor da aka haɗa a layi daya tare da inductor don bayyana asarar ƙarfe. Lokacin da mitar ta yi daidai da SRF, da inductive reactance da capacitive reactance soke fita, da kuma m reactance ne sifili. A wannan lokacin, boppeadin kafa daidai yake da juriya na baƙin ƙarfe yana da girma fiye da juriya na iska, don haka rashin hasara a SRF daidai yake da asarar baƙin ƙarfe. Ɗaukar inductor mai ƙarancin ƙarfin lantarki a matsayin misali, juriyar asarar ƙarfe ta kusan 20kΩ. Idan an kiyasta ingantaccen ƙarfin ƙimar ƙarfin ƙarfe a ƙarshen ƙarshen inductor ya zama 5V, asarar ƙarfensa kusan 1.25mW, wanda kuma yana nuna cewa mafi girman juriyar asarar ƙarfe, mafi kyau.

7. Tsarin garkuwa

Tsarin marufi na inductors na ferrite ya haɗa da marasa garkuwa, masu garkuwa da su tare da manne mai maganadisu, da garkuwa, kuma akwai tazarar iska a ɗayan ɗayansu. Babu shakka, tazarar iska za ta sami ɗigon maganadisu, kuma a cikin mafi munin yanayi, zai tsoma baki tare da ƙananan siginar da ke kewaye, ko kuma idan akwai wani abu na maganadisu a kusa, za a canza ƙarfinsa. Wani tsarin marufi shine inductor foda na ƙarfe. Tunda babu tazara a cikin inductor kuma tsarin iska yana da ƙarfi, matsalar ɓarkewar filin maganadisu kadan ne. Hoto na 10 shine amfani da aikin FFT na RTO 1004 oscilloscope don auna girman filin maganadisu yayyo a sama da 3mm a sama da gefen inductor mai hatimi. Tebu na 4 ya lissafa kwatancen filin maganadisu yayyo na inductor tsarin fakiti daban-daban. Ana iya ganin cewa inductor ɗin da ba su da garkuwa suna da mafi girman ɗigon maganadisu; Inductor da aka hati suna da mafi ƙarancin ɗigon maganadisu, yana nuna mafi kyawun tasirin garkuwar maganadisu. . Bambanci a cikin girman filin maganadisu yayyo na inductor na waɗannan sifofi biyu kusan 14dB, wanda kusan sau 5 ne.

10

Hoto 10. Girman filin maganadisu yayyo wanda aka auna a 3mm sama da gefen inductor da aka hati

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Tebur 4. Kwatanta filin maganadisu yayyo na inductor tsarin fakiti daban-daban

8. hada biyu

A wasu aikace-aikacen, wani lokacin akwai nau'ikan masu sauya DC da yawa akan PCB, waɗanda galibi ana shirya su kusa da juna, kuma ana shirya inductor ɗin su daidai da juna. Idan kun yi amfani da wani nau'in mara garkuwa ko wani nau'in garkuwar jiki mai ƙarfi tare da Inductor mai maganadisu na iya haɗawa da juna don samar da tsangwama na EMI. Don haka, lokacin sanya inductor, ana ba da shawarar fara alamar polarity na inductor, kuma a haɗa wurin farawa da jujjuyawar Layer na ciki na inductor zuwa wutar lantarki mai canzawa na mai canzawa, kamar VSW na mai canza buck. wanda shine abin motsi. An haɗa tashar tashar fitarwa zuwa capacitor na fitarwa, wanda shine matsayi na tsaye; Saboda haka iskan waya ta jan ƙarfe ta samar da wani mataki na garkuwar filin lantarki. A cikin tsarin wiring na multiplexer, gyara polarity na inductance yana taimakawa wajen gyara girman inductance na juna da guje wa wasu matsalolin EMI da ba zato ba tsammani.

Aikace-aikace:

Babin da ya gabata ya tattauna ainihin kayan aiki, tsarin kunshin, da mahimman halayen lantarki na inductor. Wannan babin zai yi bayanin yadda za a zaɓi ƙimar inductance mai dacewa na mai canza kuɗaɗe da la'akari don zabar inductor da ke samuwa a kasuwa.

Kamar yadda aka nuna a lissafin (5), ƙimar inductor da mitar sauyawa na mai canzawa zai shafi inductor ripple current (ΔiL). Inductor ripple halin yanzu zai gudana ta cikin capacitor na fitarwa kuma ya shafi ripple halin yanzu na ƙarfin fitarwa. Sabili da haka, zai shafi zaɓin capacitor na fitarwa kuma yana ƙara rinjayar girman girman ƙarfin fitarwa. Bugu da ƙari kuma, ƙimar inductance da ƙimar ƙarfin fitarwa kuma za ta shafi ƙirar ra'ayi na tsarin da martani mai ƙarfi na kaya. Zaɓin ƙimar inductance mafi girma yana da ƙarancin damuwa na halin yanzu akan capacitor, kuma yana da fa'ida don rage ƙarfin ƙarfin fitarwa kuma yana iya adana ƙarin kuzari. Koyaya, ƙimar inductance mafi girma tana nuna ƙarar girma, wato, farashi mafi girma. Sabili da haka, lokacin zayyana mai canzawa, ƙirar ƙimar inductance yana da mahimmanci.

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Ana iya gani daga dabara (5) cewa idan tazarar da ke tsakanin wutar lantarki da wutar lantarki ta fi girma, inductor ripple current zai fi girma, wanda shine mafi munin yanayin ƙirar inductor. Haɗe tare da wasu ƙididdiga masu ƙima, ƙirar ƙirar inductance na mai canzawa zuwa ƙasa yawanci yakamata a zaɓa ƙarƙashin yanayin matsakaicin matsakaicin ƙarfin shigarwa da cikakken kaya.

Lokacin zayyana darajar inductance, ya zama dole a yi ciniki tsakanin inductor ripple current da girman inductor, kuma an bayyana ma'anar ripple current ( ripple current factor; γ) anan, kamar yadda a cikin dabara (6).

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Sauya dabara (6) zuwa dabara (5), ƙimar inductance za a iya bayyana shi azaman dabara (7).

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Dangane da dabara (7), lokacin da bambanci tsakanin ƙarfin shigarwa da fitarwa ya fi girma, ƙimar γ za a iya zaɓar mafi girma; akasin haka, idan shigarwa da ƙarfin fitarwa sun fi kusa, ƙirar ƙimar γ dole ne ya zama ƙarami. Don zaɓar tsakanin inductor ripple halin yanzu da girman, bisa ga ƙimar ƙwarewar ƙira ta gargajiya, γ yawanci 0.2 zuwa 0.5 ne. Mai zuwa yana ɗaukar RT7276 a matsayin misali don kwatanta lissafin inductance da zaɓin inductor na kasuwanci.

Misalin ƙira: An ƙera shi tare da RT7276 ci gaba akai-akai (Advanced Constant On-Time; ACOTTM) gyare-gyaren matakan daidaitawa, mitar sauyawarsa shine 700 kHz, ƙarfin shigarwar shine 4.5V zuwa 18V, kuma ƙarfin fitarwa shine 1.05V. . Cikakken nauyin halin yanzu shine 3A. Kamar yadda aka ambata a sama, dole ne a tsara ƙimar inductance a ƙarƙashin yanayin matsakaicin matsakaicin ƙarfin shigarwa na 18V da cikakken nauyin 3A, ƙimar γ ana ɗaukar shi azaman 0.35, kuma ƙimar da ke sama an canza shi zuwa lissafin (7), inductance. darajar ita ce

Yi amfani da inductor tare da ƙimar inductance na yau da kullun na 1.5 µH. Madadin dabara (5) don lissafin inductor ripple current kamar haka.

Saboda haka, kololuwar halin yanzu na inductor shine

Kuma ingancin ingancin inductor current (IRMS) shine

Saboda bangaren inductor ripple karami ne, ingancin ingancin inductor current shine bangarensa na DC, kuma ana amfani da wannan ingantaccen darajar a matsayin ginshikin zabar inductor da aka tantance IDC na yanzu. Tare da ƙira 80% derating (derating), buƙatun inductance sune:

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

Tebu na 5 ya lissafa samammun inductor na jerin TDK daban-daban, masu kama da girman amma daban a tsarin kunshin. Ana iya gani daga tebur cewa jikewar halin yanzu da ƙimar halin yanzu na inductor mai hatimi (SPM6530T-1R5M) suna da girma, kuma juriya na thermal ƙanƙara ne kuma ƙarancin zafi yana da kyau. Bugu da ƙari, bisa ga tattaunawa a cikin babin da ya gabata, ainihin kayan aikin inductor mai hatimi shine ƙarfe foda, don haka an kwatanta shi da ferrite core na Semi-shielded (VLS6045EX-1R5N) da kuma kariya (SLF7055T-1R5N) inductor. tare da manne magnetic. , Yana da kyawawan halaye na son rai na DC. Hoto 11 yana nuna ingantaccen kwatancen inductor daban-daban da aka yi amfani da su zuwa RT7276 ci gaba akai-akai akan lokaci mai daidaitawa mai jujjuya matakin ƙasa. Sakamakon ya nuna cewa bambancin inganci tsakanin ukun ba shi da mahimmanci. Idan kayi la'akari da ɓarkewar zafi, halaye na nuna son kai na DC da batutuwan ɓarkewar filin maganadisu, ana ba da shawarar yin amfani da inductor SPM6530T-1R5M.

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Table 5. Kwatanta inductances na daban-daban jerin TDK

11

Hoto 11. Kwatanta iyawar mai canzawa tare da inductor daban-daban

Idan ka zaɓi tsarin kunshin iri ɗaya da ƙimar inductance, amma ƙananan inductor masu girma, irin su SPM4015T-1R5M (4.4 × 4.1 × 1.5mm), kodayake girmansa kaɗan ne, amma juriya na DC RDC (44.5mΩ) da juriya na thermal ΘTH ( 51˚C) /W) Ya fi girma. Ga masu canzawa na ƙayyadaddun bayanai iri ɗaya, ingantaccen ƙimar halin yanzu da inductor ya jure shima iri ɗaya ne. Babu shakka, juriya na DC zai rage tasiri a ƙarƙashin nauyi mai nauyi. Bugu da ƙari, babban juriya na thermal yana nufin ƙarancin zafi mara kyau. Sabili da haka, lokacin zabar inductor, ba lallai ba ne kawai don la'akari da fa'idodin rage girman girman, har ma don kimanta gazawar sa.

A karshe

Inductance yana ɗaya daga cikin abubuwan da aka saba amfani da su a cikin sauya wutar lantarki, waɗanda za a iya amfani da su don ajiyar makamashi da tacewa. Duk da haka, a cikin zane-zane, ba kawai ƙimar inductance ba ne ya kamata a kula da shi ba, amma sauran sigogi ciki har da juriya na AC da ƙimar Q, haƙurin halin yanzu, jikewar ƙarfe na ƙarfe, da tsarin kunshin, da dai sauransu, duk sigogi ne waɗanda dole ne su kasance. a yi la'akari lokacin zabar inductor. . Waɗannan sigogi yawanci suna da alaƙa da ainihin kayan aiki, tsarin masana'anta, da girma da farashi. Sabili da haka, wannan labarin yana gabatar da halaye na nau'ikan nau'ikan nau'ikan ƙarfe daban-daban da kuma yadda za'a zaɓi inductance mai dacewa azaman nuni don ƙirar samar da wutar lantarki.