izindaba

Ama-Capacitor angenye yezingxenye ezivame ukusetshenziswa kakhulu kumabhodi esekethe.Njengoba inani lezinto zikagesi (kusuka kumakhalekhukhwini ukuya ezimotweni) liqhubeka nokwanda, kanjalo nesidingo sama-capacitor.Ubhubhane lwe-Covid 19 luphazamise uchungechunge lokuhlinzekwa kwezingxenye zomhlaba wonke ezivela kuma-semiconductors. ezingxenyeni ze-passive, nama-capacitor abelokhu eshoda1.
Izingxoxo ngesihloko sama-capacitor zingaguqulwa kalula zibe yincwadi noma isichazamazwi.Okokuqala, kunezinhlobo ezahlukene zama-capacitor, njengama-electrolytic capacitor, ama-film capacitor, ama-ceramic capacitors nokunye.Khona-ke, ohlotsheni olufanayo, kunezinhlobo ezahlukene izinto ze-dielectric.Kukhona namakilasi ahlukene.Mayelana nesakhiwo somzimba, kunezinhlobo ezimbili ze-terminal kanye ne-threminal capacitor.Kuphinde kube ne-X2Y uhlobo lwe-capacitor, okuyi-pair of Y capacitor ehlanganiswe eyodwa.Kuthiwani ngama-supercapacitor ?Iqiniso liwukuthi, uma uhlala phansi bese uqala ukufunda imihlahlandlela yokukhetha i-capacitor evela kubakhiqizi abakhulu, ungachitha usuku kalula!
Njengoba lesi sihloko sikhuluma ngezinto eziyisisekelo, ngizosebenzisa indlela ehlukile njengenjwayelo.Njengoba kushiwo ngaphambili, iziqondiso zokukhetha i-capacitor zingatholakala kalula kumawebhusayithi abahlinzeki 3 no-4, futhi onjiniyela bensimu bangakwazi ukuphendula imibuzo eminingi mayelana nama-capacitors.Kulesi sihloko, Ngeke ngiphinde lokho ongakuthola ku-inthanethi, kodwa ngizobonisa indlela yokukhetha nokusebenzisa ama-capacitor ngezibonelo ezingokoqobo.Ezinye izici ezingaziwa kakhulu zokukhetha i-capacitor, njengokuwohloka kwe-capacitance, nazo zizohlanganiswa.Ngemva kokufunda lesi sihloko, wena Kufanele ube nokuqonda okuhle kokusetshenziswa kwama-capacitor.
Eminyakeni edlule, ngenkathi ngisebenza enkampanini eyenza okokusebenza kwe-elekthronikhi, sasinombuzo wenhlolokhono kanjiniyela we-power electronics.Kumdwebo wohlelo lomkhiqizo okhona, sizobuza abangase bakhethelwe ukhetho “Uyini umsebenzi we-DC link electrolytic i-capacitor?" kanye nokuthi "Uyini umsebenzi we-ceramic capacitor eduze kwe-chip?" Sithemba ukuthi impendulo efanele i-DC bus capacitor Isetshenziselwa ukugcinwa kwamandla, ama-capacitor e-ceramic asetshenziselwa ukuhlunga.
Impendulo “elungile” esiyifunayo empeleni ibonisa ukuthi wonke umuntu oseqenjini lokuklama ubheka ama-capacitor ngokombono wesifunda olula, hhayi ngokombono wethiyori yenkundla.Iphuzu lokubuka lethiyori yesifunda alilungile.Kumafrikhwensi aphansi (kusuka ku-kHz embalwa ku-MHz embalwa), i-circuit theory ngokuvamile ingachaza inkinga kahle.Lokhu kungenxa yokuthi emazingeni aphansi, isignali ngokuyinhloko imodi yokuhlukanisa.Ngokusebenzisa i-circuit theory, singabona i-capacitor eboniswe ku-Figure 1, lapho ukuphikiswa kochungechunge olulinganayo ( I-ESR) kanye ne-equivalent series inductance (ESL) yenza ukuvinjelwa kwe-capacitor kushintshe nemvamisa.
Le modeli ichaza ngokugcwele ukusebenza kwesifunda lapho isifunda sishintshwa kancane.Kodwa-ke, njengoba imvamisa ikhula, izinto ziba nzima nakakhulu.Ngesikhathi esithile, ingxenye iqala ukubonisa ukungahambisani nomugqa.Lapho imvamisa inyuka, imodeli elula ye-LCR inemikhawulo yayo.
Namuhla, uma ngibuzwa umbuzo ofanayo wokuxoxisana, ngizogqoka izibuko zami zokubheka i-theory yensimu futhi ngithi zombili izinhlobo ze-capacitor ziyimishini yokugcina amandla.Umehluko wukuthi ama-electrolytic capacitors angagcina amandla amaningi kunama-ceramic capacitors.Kodwa mayelana nokudluliswa kwamandla kagesi. , ama-capacitors e-ceramic angadlulisela amandla ngokushesha.Lokhu kuchaza ukuthi kungani ama-capacitor e-ceramic adinga ukubekwa eduze kwe-chip, ngoba i-chip ine-frequency yokushintsha ephezulu kanye nesivinini sokushintsha uma kuqhathaniswa nomjikelezo wamandla amakhulu.
Kusukela kulo mbono, singamane sichaze izindinganiso ezimbili zokusebenza ze-capacitor.Eyodwa ukuthi ingakanani amandla i-capacitor engakwazi ukuwagcina, kanti enye ukuthi la mandla angadluliswa ngokushesha kangakanani.Zombili zincike endleleni yokukhiqiza ye-capacitor, impahla ye-dielectric, ukuxhumana ne-capacitor, njalonjalo.
Lapho inkinobho kumjikelezo ivaliwe (bheka Umfanekiso 2), kubonisa ukuthi umthwalo udinga amandla avela emthonjeni wamandla.Ijubane le swishi elivala ngalo linquma ukuphuthuma kwesidingo samandla.Njengoba amandla ehamba ngesivinini sokukhanya (isigamu ijubane lokukhanya ezintweni ze-FR4), kuthatha isikhathi ukudlulisa amandla.Ngaphezu kwalokho, kukhona ukungafani kokuphazamiseka phakathi komthombo kanye nolayini wokudlulisela kanye nomthwalo.Lokhu kusho ukuthi amandla ngeke adluliselwe ohambweni olulodwa, kodwa ngobuningi. uhambo olujikelezayo5, yingakho lapho iswishi ishintsha ngokushesha, sibona ukubambezeleka nokukhala ekushintsheni kwe-waveform.
Umfanekiso 2: Kuthatha isikhathi ukuthi amandla andise emkhathini; ukungahambisani kahle kwe-impedance kubangela uhambo oluningi lokuya nokubuya lokudluliswa kwamandla.
Iqiniso lokuthi ukudluliswa kwamandla kuthatha isikhathi kanye nohambo oluningi lokujikeleza lisitshela ukuthi sidinga ukuthola umthombo wamandla eduze nomthwalo ngangokunokwenzeka, futhi sidinga ukuthola indlela yokudlulisa amandla ngokushesha.Okokuqala ngokuvamile kufinyelelwa ngokunciphisa umzimba ibanga phakathi komthwalo, ukushintshwa kanye ne-capacitor.Lowo wokugcina ufinyelelwa ngokuqoqa iqembu lama-capacitor ane-impedance encane kakhulu.
I-Field theory iphinde ichaze ukuthi yini ebangela umsindo wemodi evamile.Ngamafuphi, umsindo wemodi evamile ukhiqizwa lapho isidingo samandla omthwalo singahlangabezwana ngaso ngesikhathi sokushintsha.Ngakho-ke, amandla agcinwe esikhaleni phakathi komthwalo namakhondakta aseduze azonikezwa ukuze asekele. isidingo sesinyathelo.Isikhala phakathi komthwalo kanye namakhondaktha aseduze yilokho esikubiza ngokuthi i-parasitic/mutual capacitance (bheka Umfanekiso 2).
Sisebenzisa izibonelo ezilandelayo ukuze sibonise indlela yokusebenzisa ama-electrolytic capacitor, i-multilayer ceramic capacitors (MLCC), nama-film capacitors.Kokubili i-circuit kanye ne-field theory isetshenziselwa ukuchaza ukusebenza kwama-capacitor akhethiwe.
Ama-electrolytic capacitor asetshenziswa kakhulu kusixhumanisi se-DC njengomthombo wamandla oyinhloko.Ukukhethwa kwe-electrolytic capacitor kuvame ukuncika kulokhu:
Ngokusebenza kwe-EMC, izici ezibaluleke kakhulu zama-capacitor ziyi-impedance kanye nezici zemvamisa.Ukukhishwa kwe-low-frequency eyenziwa njalo kuncike ekusebenzeni kwe-DC link capacitor.
I-impedance yesixhumanisi se-DC ayincikile kuphela ku-ESR ne-ESL ye-capacitor, kodwa futhi nasendaweni ye-loop eshisayo, njengoba kuboniswe kuMfanekiso 3.Indawo enkulu ye-thermal loop isho ukuthi ukudluliswa kwamandla kuthatha isikhathi eside, ngakho ukusebenza izothinteka.
I-converter ye-DC-DC eyehlayo yakhelwe ukufakazela lokhu.Ukusethwa kokuhlolwa kwe-EMC kwangaphambilini okuboniswe kuMfanekiso 4 kwenza ukuskena kokukhishwayo okwenziwe phakathi kuka-150kHz no-108MHz.
Kubalulekile ukuqinisekisa ukuthi ama-capacitor asetshenziswe kulolu cwaningo lwecala wonke avela kumkhiqizi ofanayo ukuze agweme ukungezwani kwezici ze-impedance.Lapho u-soldering i-capacitor ku-PCB, qiniseka ukuthi awekho umkhondo omude, njengoba lokhu kuzokwandisa i-ESL i-capacitor.Umfanekiso 5 ukhombisa ukucushwa okuthathu.
Imiphumela eyenziwe yalokhu kumiswa kokuthathu ikhonjisiwe kuMfanekiso 6.Kungabonakala ukuthi, uma kuqhathaniswa ne-capacitor eyodwa engu-680 µF, ama-capacitor amabili angu-330 µF azuza ukusebenza kokunciphisa umsindo okungu-6 dB phezu kwebanga elibanzi lefrikhwensi.
Kusukela kumbono wesifunda, kungashiwo ukuthi ngokuxhuma ama-capacitor amabili ngokuhambisana, kokubili i-ESL ne-ESR ihhafu. , ukwehlisa ngempumelelo sonke isikhathi sokudluliswa kwamandla.Kodwa-ke, kumafrikhwensi aphezulu, umehluko phakathi kwama-capacitor amabili angu-330 µF kanye ne-680 µF capacitor izoncipha.Lokhu kungenxa yokuthi umsindo ovela phezulu ukhombisa impendulo enganele yamandla.Lapho usondeza i-capacitor engu-330 µF eduze ukushintshwa, sinciphisa isikhathi sokudlulisa amandla, okwandisa ngokuphumelelayo impendulo yesinyathelo se-capacitor.
Umphumela usitshela isifundo esibaluleke kakhulu.Ukwandisa amandla e-capacitor eyodwa ngokuvamile ngeke kusekele isidingo sesinyathelo samandla engeziwe.Uma kungenzeka, sebenzisa izingxenye ezincane ze-capacitive.Kunezizathu eziningi ezinhle zalokhu.Eyokuqala yizindleko.Ngokuvamile ukukhuluma, ngosayizi wephakheji ofanayo, izindleko ze-capacitor zikhuphuka kakhulu nge-value ye-capacitance.Ukusebenzisa i-capacitor eyodwa kungase kubize kakhulu kunokusebenzisa ama-capacitor amaningana amancane.Isizathu sesibili ubukhulu.Isici esilinganiselwe ekwakhiweni komkhiqizo ngokuvamile ukuphakama wezingxenye.Kuma-capacitor amakhulu, ukuphakama kuvame ukuba kukhulu kakhulu ekuklanyweni komkhiqizo.Isizathu sesithathu ukusebenza kwe-EMC esikubone esifundweni secala.
Esinye isici okufanele icatshangelwe lapho usebenzisa i-electrolytic capacitor ukuthi uma uxhuma ama-capacitor amabili ochungechungeni ukuze wabelane nge-voltage, uzodinga i-bancing resistor 6.
Njengoba kushiwo ngaphambili, ama-ceramic capacitors angamadivayisi amancane angakwazi ukunikeza amandla ngokushesha.Ngivame ukubuzwa umbuzo othi "Ngidinga i-capacitor engakanani?"Impendulo yalo mbuzo iwukuthi kuma-capacitors e-ceramic, inani le-capacitance akufanele libe elibaluleke kangako. Okubalulekile okucatshangelwayo lapha ukunquma ukuthi isivinini sokudlulisa amandla kusiphi imvamisa esanele kuhlelo lwakho lokusebenza.Uma ukukhishwa okwenziwe kwehluleka ku-100 MHz, khona-ke i-capacitor ene-impedance encane kakhulu ku-100 MHz izoba yisinqumo esihle.
Lokhu okunye ukungaqondi kahle kwe-MLCC. Ngibone onjiniyela bechitha amandla amaningi bekhetha ama-capacitor e-ceramic ane-ESR ne-ESL ephansi kakhulu ngaphambi kokuxhuma ama-capacitor endaweni eyireferensi ye-RF ngokusebenzisa imikhondo emide. ephansi kune-inductance yokuxhuma ebhodini.I-inductance yokuxhuma kuseyipharamitha ebaluleke kakhulu ethinta i-impedance ephezulu ye-ceramic capacitors7.
Umfanekiso wesi-7 ubonisa isibonelo esibi.Ukulandelela okude (amayintshi angu-0.5 ubude) kwethula okungenani i-inductance engu-10nH. Umphumela wokulingisa ubonisa ukuthi ukuvinjelwa kwe-capacitor kuba phezulu kakhulu kunalokho okulindelekile endaweni yemvamisa (50 MHz).
Enye yezinkinga nge-MLCCs ukuthi ijwayele ukuhambisana nesakhiwo se-inductive ebhodini.Lokhu kungabonakala esibonelweni esiboniswe kuMfanekiso 8, lapho ukusetshenziswa kwe-10 µF MLCC kwethula i-resonance cishe ku-300 kHz.
Unganciphisa i-resonance ngokukhetha ingxenye nge-ESR enkulu noma ngokumane ubeke i-resistor value encane (efana ne-1 ohm) ochungechungeni nge-capacitor.Lolu hlobo lwendlela lusebenzisa izingxenye ezilahlekile ukuze lucindezele uhlelo.Enye indlela ukusebenzisa enye i-capacitance inani lokuhambisa i-resonance endaweni ephansi noma ephakeme ye-resonance.
Ama-filimi capacitor asetshenziswa ezinhlelweni eziningi.Ama-capacitor akhethwayo okuguqula amandla e-DC-DC aphezulu futhi asetshenziswa njengezihlungi zokucindezela ze-EMI kuzo zonke izintambo zamandla (AC ne-DC) kanye nokucushwa kokuhlunga kwemodi evamile.Sithatha i-X capacitor njenge isibonelo sokukhombisa amanye amaphuzu asemqoka okusebenzisa ama-capacitor amafilimu.
Uma kwenzeka isigameko sokuhlinzwa, kusiza ukukhawulela ukucindezela kwamandla kagesi aphezulu kulayini, ngakho-ke kuvame ukusetshenziswa ne-transient voltage suppressor (TVS) noma i-metal oxide varistor (MOV).
Kungenzeka ukuthi usukwazi konke lokhu, kodwa bewazi ukuthi i-capacitance value ye-X capacitor ingancishiswa kakhulu ngeminyaka yokusetshenziswa?Lokhu kuyiqiniso ikakhulukazi uma i-capacitor isetshenziswa endaweni enomswakama.Ngibonile inani le-capacitance i-X capacitor yehla kuphela kumaphesenti ambalwa yenani elilinganiselwe phakathi nonyaka noma emibili, ngakho uhlelo olwaklanywa ekuqaleni nge-X capacitor empeleni lwalahlekelwa yikho konke ukuvikela okungenzeka ukuthi i-capacitor yangaphambili.
Manje-ke, kwenzekeni?Umoya womswakamo ungase uvuze ku-capacitor, phezulu ocingweni naphakathi kwebhokisi kanye ne-epoxy potting compound.I-aluminium metallization ingase ifakwe i-oxidized.I-Alumina iyisivikeli esihle sikagesi, ngaleyo ndlela sinciphise amandla.Lena yinkinga ukuthi wonke ama-filimi capacitor azohlangana nayo.Indaba engikhuluma ngayo ukushuba kwefilimu.Imikhiqizo ye-capacitor ehlonishwayo zisebenzisa amafilimu ashubile, okuholela ekubeni nama-capacitor amakhulu kunamanye ama-brand.Ifilimu elincanyana lenza i-capacitor ingabi namandla okulayisha ngokweqile (i-voltage, yamanje, noma izinga lokushisa), futhi mancane amathuba okuthi likwazi ukuziphilisa.
Uma i-X capacitor ingaxhunywanga unomphela ekunikezeni amandla, ngakho-ke awudingi ukukhathazeka.Isibonelo, ngomkhiqizo onomshini oqinile phakathi kokunikezwa kwamandla kanye ne-capacitor, usayizi ungaba obaluleke kakhulu kunokuphila, futhi khona-ke ungakhetha i-capacitor encane.
Kodwa-ke, uma i-capacitor ixhunywe unomphela kumthombo wamandla, kufanele ithembeke kakhulu.I-oxidation yama-capacitor ayinakugwemeka.Uma impahla ye-capacitor epoxy iyikhwalithi enhle futhi i-capacitor ayivami ukuvezwa emazingeni okushisa aphezulu, ukwehla inani kufanele libe lincane.
Kulesi sihloko, okokuqala wethula umbono we-field theory of capacitors.Izibonelo ezisebenzayo kanye nemiphumela yokulingisa ibonisa indlela yokukhetha nokusebenzisa izinhlobo ezivame kakhulu ze-capacitor.Sithemba ukuthi lolu lwazi lungakusiza uqonde indima yama-capacitor ekwakhiweni kwe-elekthronikhi kanye ne-EMC ngokugcwele.
UDkt. Min Zhang ungumsunguli kanye nomeluleki omkhulu we-EMC ye-Mach One Design Ltd, inkampani yobunjiniyela ezinze e-UK egxile ekuxhumaneni ne-EMC, ukuxazulula izinkinga nokuqeqesha. Ulwazi lwakhe olujulile kuma-electronics, i-digital electronics, motors kanye nomklamo womkhiqizo uzuzile. izinkampani emhlabeni jikelele.
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