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Capacitors chimwe chezvinhu zvinowanzoshandiswa pamapuranga edunhu. Sezvo nhamba yezvigadzirwa zvemagetsi (kubva kunharembozha kusvika kumotokari) ichiramba ichiwedzera, ndizvo zvinoitawo kudiwa kwema capacitors. Denda reCovid 19 rakanganisa chikamu chepasirese chekugovera cheni kubva kune semiconductors kuenda kuzvinhu zvisingaite, uye ma capacitor anga ari mupfupi1.
Hurukuro pamusoro pemusoro we capacitor inogona kushandurwa zviri nyore kuita bhuku kana duramazwi. Kutanga, kune marudzi akasiyana e-capacitors, akadai se electrolytic capacitors, film capacitors, ceramic capacitors nezvimwe zvakadaro. Zvadaro, mumhando imwechete, kune zvakasiyana-siyana dielectric zvinhu. Kunewo makirasi akasiyana. Kana iri chimiro chemuviri, kune maviri-terminal uye matatu-terminal capacitor marudzi. Iko kune zvakare X2Y mhando capacitor, iyo inonyanya kuve mbiri yeY capacitors yakavharirwa mune imwe. Zvakadini ne supercapacitors? Chokwadi ndechekuti, kana ukagara pasi uye wotanga kuverenga madhairekitori ekusarudza capacitor kubva kuvagadziri vakuru, unogona kupedza zuva nyore!
Sezvo chinyorwa ichi chiri pamusoro pekutanga, ini ndichashandisa nzira yakasiyana semazuva ose. Sezvambotaurwa, madhairekitori ekusarudza capacitor anogona kuwanikwa zviri nyore pamawebhusaiti evatengesi 3 uye 4, uye mainjiniya emumunda anogona kazhinji kupindura mibvunzo yakawanda nezve capacitors. Muchikamu chino, ini handisi kuzodzokorora zvaunogona kuwana paInternet, asi ndicharatidza nzira yekusarudza uye kushandisa capacitors kuburikidza nemienzaniso inoshanda. Zvimwe zvishoma zvinozivikanwa zvecapacitor kusarudzwa, senge capacitance degradation, zvichavharwa zvakare. Mushure mekuverenga chinyorwa ichi, iwe unofanirwa kuve nekunzwisisa kwakanaka kwekushandiswa kwema capacitors.
Makore apfuura, pandakanga ndichishanda mukambani yaigadzira midziyo yemagetsi, takava nemubvunzo webvunzurudzo kune injiniya wemagetsi emagetsi. Pane dhizaini yechigadzirwa chiripo, isu tichabvunza vangangove kukwikwidza "Ndeipi basa reDC link electrolytic capacitor?" uye "Ndeipi basa receramic capacitor iri padyo nechip?" Tinovimba kuti mhinduro chaiyo ndeye DC bhazi capacitor Inoshandiswa kuchengetedza simba, ceramic capacitors inoshandiswa kusefa.
Mhinduro "yakarurama" yatinotsvaka inonyatsoratidza kuti munhu wose ari muchikwata chekugadzira anotarisa capacitors kubva kune imwe nzvimbo yedunhu, kwete kubva kune imwe nzvimbo yezvidzidzo. Pfungwa yekuona yedunhu dzidziso haina kukanganisa. Panguva yakaderera frequencies (kubva pashoma kHz kusvika kune mashoma MHz), redunhu dzidziso inogona kazhinji kutsanangura dambudziko zvakanaka. Izvi zvinodaro nekuti pazasi mafrequency, chiratidzo chinonyanya kusiyanisa maitiro. Tichishandisa dzidziso yedunhu, tinogona kuona iyo capacitor inoratidzwa muMufananidzo 1, uko yakaenzana inoteedzana kuramba (ESR) uye yakaenzana inoteedzana inductance (ESL) inoita iyo impedance ye capacitor ichinje ne frequency.
Uyu muenzaniso unotsanangura zvizere kushanda kwedunhu apo dunhu rinoshandurwa zvishoma nezvishoma. Nekudaro, sezvo kuwanda kunowedzera, zvinhu zvinowedzera uye zvakanyanya kuoma. Pane imwe nguva, chikamu chinotanga kuratidza chisiri-mutsara. Kana iyo frequency inowedzera, iyo yakapfava LCR modhi ine painogumira.
Nhasi, dai ndakabvunzwa mubvunzo mumwechete wekubvunzurudza, ndaizopfeka magirazi ekucherechedza dzidziso yemunda uye ndichitaura kuti zvose capacitor mhando midziyo yekuchengetedza simba. Musiyano ndewekuti electrolytic capacitors inogona kuchengeta simba rakawanda kupfuura ceramic capacitors. Asi maererano nekufambiswa kwesimba, ceramic capacitors inogona kutumira simba nekukurumidza. Izvi zvinotsanangura chikonzero nei ceramic capacitors ichida kuiswa padivi peiyo chip, nekuti chip ine yakakwirira switching frequency uye switching kasi kana ichienzaniswa neiyo huru simba redunhu.
Kubva pamaonero aya, tinogona kungotsanangura maitiro maviri ekuita ma capacitors. Imwe ndeye simba rakawanda sei iyo capacitor inogona kuchengeta, uye imwe yacho inokurumidza sei simba iri rinogona kutamiswa. Zvose zvinoenderana nenzira yekugadzira ye capacitor, dielectric material, kuwirirana ne capacitor, nezvimwe zvakadaro.
Kana shanduko yedunhu yakavharwa (ona Mufananidzo 2), inoratidza kuti mutoro unoda simba kubva kune simba. Iyo yekumhanyisa iyo switch iyi inovhara inosarudza kukurumidza kwekuda kwesimba. Sezvo simba richifamba nekumhanya kwechiedza (hafu yekumhanya kwechiedza muFR4 zvinhu), zvinotora nguva kuendesa simba. Mukuwedzera, pane kusawirirana kwe impedance pakati pechitubu uye tambo yekutumira uye mutoro. Izvi zvinoreva kuti simba harizombofa rakafambiswa murwendo rumwe, asi mukufamba kwakawanda kutenderera5, ndosaka switch ikakurumidza kuchinjika, tinoona kunonoka uye kurira mukuchinja waveform.
Mufananidzo 2: Zvinotora nguva kuti simba ripararire muchadenga; impedance kusawirirana kunokonzeresa nzendo dzakawanda dzekutenderera dzekutamisa simba.
Icho chokwadi chekuti simba rekutakura rinotora nguva uye nzendo dzakawanda dzekutenderera rinotiudza kuti tinoda kufambisa simba padhuze nepazvinogona kumutoro, uye isu tinoda kutsvaga nzira yekuiburitsa nekukurumidza. Yokutanga inowanikwa nekudzikisa kureba kwemuviri pakati pemutoro, chinja uye capacitor. Iyo yekupedzisira inowanikwa nekuunganidza boka rema capacitor ane diki impedance.
Munda theory inotsanangurawo kuti chii chinokonzera common mode ruzha. Muchidimbu, ruzha rwemodhi yakajairika inogadzirwa kana simba rekuda remutoro risingazadziswe panguva yekuchinja. Naizvozvo, simba rakachengetwa munzvimbo iri pakati pemutoro uye makondakita ari pedyo achapihwa kutsigira danho rinodiwa. Nzvimbo iri pakati pemutoro nemakondakita ari pedyo ndiyo yatinoti parasitic/mutual capacitance (ona Mufananidzo 2).
Isu tinoshandisa mienzaniso inotevera kuratidza mashandisirwo emagetsi emagetsi emagetsi, multilayer ceramic capacitors (MLCC), uye mafirimu capacitor. Zvose zvedunhu uye dzidziso yemunda inoshandiswa kutsanangura kushanda kwevakasarudzwa capacitors.
Electrolytic capacitors inonyanya kushandiswa muDC link seyakanyanya simba sosi. Sarudzo ye electrolytic capacitor inowanzoenderana ne:
Kune EMC mashandiro, akanyanya kukosha maitiro e capacitors ndeye impedance uye frequency maitiro. Low-frequency yakaitwa emissions inogara ichienderana nekuita kweiyo DC link capacitor.
Iyo impedance yeDC link inotsamira kwete chete paESR uye ESL ye capacitor, asiwo panharaunda ye thermal loop, sezvakaratidzwa muFigure 3. Iyo yakakura inopisa loop nzvimbo inoreva kuti kuendesa simba kunotora nguva yakareba, saka kuita zvichakanganiswa.
Nhanho-pasi DC-DC converter yakavakwa kuratidza izvi. Iyo pre-kutevedzera EMC bvunzo setup inoratidzwa muMufananidzo 4 inoita emission scan pakati pe150kHz ne108MHz.
Izvo zvakakosha kuve nechokwadi chekuti ma capacitor anoshandiswa mune ino nyaya yekudzidza ese ari kubva kune imwechete mugadziri kudzivirira mutsauko we impedance maitiro. Paunenge uchitengesa iyo capacitor paPCB, ita shuwa kuti hapana marefu anotungamira, sezvo izvi zvichawedzera ESL ye capacitor. Mufananidzo 5 unoratidza magadzirirwo matatu.
Mhedzisiro yakaitwa yezvigadziriso zvitatu izvi inoratidzwa muMufananidzo 6. Zvinogona kuonekwa kuti, zvichienzaniswa ne680 µF capacitor, maviri 330 µF capacitor anowana kuita kwekudzikisa ruzha kwe6 dB pane yakakura frequency renji.
Kubva kumusangano wedunhu, zvinogona kutaurwa kuti nekubatanidza maviri capacitors mune zvakafanana, zvose ESL uye ESR zvakakamurwa. Kubva kumunda wedzidziso yekuona, hapana simba rimwechete, asi maviri emagetsi anopiwa kumutoro wakafanana, zvinobudirira kuderedza nguva yese yekufambisa simba. Nekudaro, pama frequency epamusoro, mutsauko uripo pakati pemaviri 330 µF capacitor uye imwe 680 µF capacitor inoderera. Izvi zvinodaro nekuti ruzha rwepamusoro runoratidza kusakwana danho rekuita simba. Kana uchifambisa 330 µF capacitor padhuze neshanduko, isu tinoderedza nguva yekufambisa simba, iyo inonyatso kuwedzera nhanho mhinduro ye capacitor.
Mugumisiro unotiudza chidzidzo chinokosha zvikuru. Kuwedzera capacitance yeimwe capacitor kazhinji haizotsigire danho rekuda kwesimba rakawanda. Kana zvichibvira, shandisa mamwe madiki capacitive components. Pane zvikonzero zvakawanda zvakanaka zveizvi. Chekutanga imari. Kazhinji kutaura, kune imwechete saizi yepasuru, mutengo we capacitor unowedzera zvakanyanya neiyo capacitance kukosha. Kushandisa imwe capacitor kunogona kudhura pane kushandisa akati wandei madiki capacitor. Chikonzero chechipiri ukuru. Chinhu chinodzikamisa mukugadzirwa kwechigadzirwa kunowanzo kukwirira kwezvikamu. Kune makuru-capacitor capacitors, kureba kunowanzove kwakakura, izvo zvisina kukodzera kugadzirwa kwechigadzirwa. Chikonzero chechitatu kuita kweEMC kwatakaona muchidzidzo chenyaya.
Chimwe chinhu chekufunga kana uchishandisa electrolytic capacitor ndechekuti kana iwe ukabatanidza maviri capacitor munhevedzano kugovera voltage, iwe unozoda balancing resistor 6.
Sezvambotaurwa, ceramic capacitors midziyo midiki inogona kukurumidza kupa simba. Ini ndinowanzo kubvunzwa mubvunzo "Ingani capacitor yandinoda?" Mhinduro kumubvunzo uyu ndeyekuti ceramic capacitors, iyo capacitance kukosha haifanirwe kuve yakakosha. Iyo yakakosha yekutarisisa pano ndeyekuona kuti ndeipi frequency yekumhanyisa simba rekufambisa inokwana application yako. Kana iyo yakaitwa emission ikakundikana pa100 MHz, ipapo iyo capacitor ine diki impedance pa100 MHz ichave sarudzo yakanaka.
Uku ndiko kumwe kusanzwisisa kweMLCC. Ndakaona mainjiniya vachipedza simba rakawanda vachisarudza ceramic capacitors ine yakaderera ESR uye ESL isati yabatanidza ma capacitor kune iyo RF referensi poindi kuburikidza nematehwe marefu. Zvakakodzera kutaura kuti iyo ESL yeMLCC inowanzo kuderera pane yekubatanidza inductance pabhodhi. Yekubatanidza inductance ichiri yakakosha paramende inobata yakakwira frequency impedance yeceramic capacitors7.
Mufananidzo 7 unoratidza muenzaniso wakashata. Tsanangudzo refu (0.5 inches kureba) inosuma inokwana 10nH inductance. Mhedzisiro yekuenzanisa inoratidza kuti iyo impedance ye capacitor inova yakanyanya kukwirira kupfuura inotarisirwa pafrequency point (50 MHz).
Rimwe rematambudziko ane MLCCs nderekuti ivo vanowanzo pindirana neiyo inductive chimiro pabhodhi. Izvi zvinogona kuonekwa mumuenzaniso unoratidzwa muMufananidzo 8, apo kushandiswa kwe10 µF MLCC kunosuma resonance pa300 kHz.
Iwe unogona kuderedza resonance nekusarudza chikamu ne ESR yakakura kana kungoisa diki kukosha resistor (senge 1 ohm) munhevedzano ine capacitor. Iyi mhando yenzira inoshandisa kurasikirwa kwezvinhu kudzvanyirira sisitimu. Imwe nzira ndeye kushandisa imwe capacitance kukosha kufambisa resonance kune yakaderera kana yepamusoro resonance point.
Mafirimu capacitor anoshandiswa mune zvakawanda zvekushandisa. Ndiwo macapacitor esarudzo epamusoro-simba DC-DC anoshandura uye anoshandiswa seEMI kudzvinyirira mafirita pamagetsi emagetsi (AC neDC) uye akajairwa-modhi yekusefa zvigadziriso. Isu tinotora X capacitor semuenzaniso kuti tiratidze mamwe makuru ekushandisa mafirimu capacitor.
Kana chiitiko chekuvhiya chikaitika, chinobatsira kudzikisira peak voltage stress pamutsara, saka inowanzo shandiswa ne transient voltage suppressor (TVS) kana metal oxide varistor (MOV).
Iwe unogona kunge uchitoziva zvese izvi, asi waiziva here kuti capacitance kukosha kwe X capacitor inogona kuderedzwa zvakanyanya nemakore ekushandiswa? Izvi zvinonyanya kuitika kana iyo capacitor inoshandiswa munzvimbo ine hunyoro. Ndakaona kukosha kweiyo X capacitor kudonha chete kune mashoma muzana eiyo yakatemerwa kukosha mukati megore kana maviri, saka sisitimu yakatanga kugadzirwa neX capacitor yakarasikirwa nedziviriro yese iyo yekumberi-yekupedzisira capacitor ingave nayo.
Saka chii chakaitika? Mhepo ine hunyoro inogona kupinda mu capacitor, kumusoro kwewaya uye pakati pebhokisi uye epoxy potting compound. Iyo aluminium metallization inogona ipapo kuve oxidized. Alumina yakanaka magetsi insulator, nokudaro kuderedza capacitance. Iri idambudziko iro ese mafirimu capacitors achasangana nawo. Nyaya yandiri kutaura ndeye kukora kwemafirimu. Mabhureki ane mukurumbira capacitor anoshandisa mafirimu akakora, zvichikonzera macapacitor makuru kupfuura mamwe mabhureki. Iyo firimu yakaonda inoita kuti capacitor isanyanya kusimba kuti iwedzere (voltage, ikozvino, kana tembiricha), uye hazvibviri kuzviporesa.
Kana iyo X capacitor isingabatanidzwe zvachose kune magetsi, saka haufanirwe kunetseka. Semuenzaniso, kune chigadzirwa chine shanduko yakaoma pakati pemagetsi uye capacitor, ukuru hunogona kunge hwakakosha kupfuura hupenyu, uye ipapo unogona kusarudza yakaonda capacitor.
Nekudaro, kana iyo capacitor yakabatana zvachose kune sosi yemagetsi, inofanirwa kuve yakavimbika zvakanyanya. Iyo oxidation ye capacitors haidzivisiki. Kana iyo capacitor epoxy zvinhu ndeyemhando yakanaka uye iyo capacitor isingawanzo kuratidzwa kune yakanyanya kutonhora, kudonha kwekukosha kunofanirwa kuve kushoma.
Muchikamu chino, chekutanga chakaunza maonero edzidziso yemunda ye capacitors. Mienzaniso inoshanda uye yekunyepedzera mhedzisiro inoratidza maitiro ekusarudza nekushandisa akajairika capacitor marudzi. Ndinovimba ruzivo urwu runogona kukubatsira kuti unzwisise basa rema capacitor mumagetsi uye EMC dhizaini zvakanyanya.
Dr. Min Zhang ndiye muvambi uye mukuru EMC chipangamazano weMach One Design Ltd, UK-based engineering kambani inoshanda neEMC kubvunza, kugadzirisa matambudziko nekudzidziswa. Ruzivo rwake rwakadzama mumagetsi emagetsi, emagetsi edhijitari, mota uye kugadzira zvigadzirwa zvakabatsira makambani pasi rese.
MuKuteerera ndiko kunobva nhau, ruzivo, dzidzo uye kurudziro yemagetsi nemagetsi einjiniya nyanzvi.
Aerospace Automotive Communications Consumer Electronics Dzidzo Simba neSimba Indasitiri Ruzivo rweTekinoroji Kurapa Mauto neNyika Dziviriro.