A wannan makon za mu ci gaba da labarin makon da ya gabata.

1.2 Na'urorin auna wutar lantarki

Dielectric da ake amfani da shi a cikin electrolytic capacitors shine aluminum oxide wanda aka samar ta hanyar tsatsa ta aluminum, tare da dielectric constant na 8 zuwa 8.5 da kuma aiki dielectric ƙarfin kusan 0.07V/A (1µm = 10000A). Duk da haka, ba zai yiwu a cimma irin wannan kauri ba. Kauri na aluminum Layer yana rage ƙarfin (takamaiman capacitance) na electrolytic capacitors saboda dole ne a yi masa fenti na aluminum foil don samar da aluminum oxide film don samun kyawawan halaye na adana makamashi, kuma saman zai samar da wurare da yawa marasa daidaituwa. A gefe guda kuma, juriyar electrolyte shine 150Ωcm don ƙarancin ƙarfin lantarki da 5kΩcm don babban ƙarfin lantarki (500V). Mafi girman juriyar electrolyte yana iyakance wutar RMS da electrolytic capacitor zai iya jurewa, yawanci zuwa 20mA/µF.

Saboda waɗannan dalilai, an tsara capacitors na lantarki don matsakaicin ƙarfin lantarki na 450V na yau da kullun (wasu masana'antun suna tsara don 600V). Saboda haka, don samun ƙarfin lantarki mafi girma, ya zama dole a cimma su ta hanyar haɗa capacitors a jere. Duk da haka, saboda bambancin juriyar rufi na kowane capacitor na lantarki, dole ne a haɗa resistor zuwa kowane capacitor don daidaita ƙarfin lantarki na kowane capacitor da aka haɗa a jere. Bugu da ƙari, capacitors na lantarki na'urori ne masu rarrafe, kuma lokacin da ƙarfin juyawar da aka yi amfani da shi ya wuce sau 1.5 Un, amsawar electrochemical yana faruwa. Lokacin da ƙarfin juyawar da aka yi amfani da shi ya isa tsayi, capacitor zai zube. Don guje wa wannan lamari, ya kamata a haɗa diode kusa da kowane capacitor lokacin da aka yi amfani da shi. Bugu da ƙari, juriyar ƙaruwar ƙarfin lantarki na capacitors na lantarki gabaɗaya sau 1.15 Un, kuma masu kyau na iya kaiwa sau 1.2 Un. Don haka masu ƙira ya kamata su yi la'akari da ba kawai ƙarfin lantarki mai aiki mai tsayayye ba har ma da ƙarfin juyawa lokacin amfani da su. A taƙaice, za a iya zana teburin kwatantawa mai zuwa tsakanin capacitors na fim da capacitors na electrolytic, duba Hoto na 1.

2. Nazarin Aikace-aikace

Masu haɗa DC-Link a matsayin matattara suna buƙatar ƙira mai ƙarfi da ƙarfin aiki mai yawa. Misali shine babban tsarin tuƙi na motar sabuwar motar makamashi kamar yadda aka ambata a Hoto na 3. A cikin wannan aikace-aikacen, mai haɗa DC yana taka rawar cire haɗin kuma da'irar tana da babban ƙarfin aiki. Fim ɗin mai haɗa DC-Link yana da fa'idar iya jure manyan kwararar aiki (Irms). Ɗauki sabbin sigogin motar makamashi 50~60kW a matsayin misali, sigogi sune kamar haka: ƙarfin lantarki mai aiki 330 Vdc, ƙarfin lantarki mai juyawa 10Vrms, ƙarfin lantarki mai juyawa 150Arms@10KHz.

Sannan ana ƙididdige mafi ƙarancin ƙarfin wutar lantarki kamar haka:

Wannan abu ne mai sauƙi a aiwatar da shi don ƙirar capacitor na fim. Idan aka yi la'akari da cewa ana amfani da capacitors na electrolytic, idan aka yi la'akari da 20mA/μF, ana ƙididdige mafi ƙarancin capacitance na capacitors na electrolytic don cika sigogin da ke sama kamar haka:

Wannan yana buƙatar na'urori masu auna electrolytic da yawa waɗanda aka haɗa a layi ɗaya don samun wannan ƙarfin.

A aikace-aikacen wuce gona da iri na wutar lantarki, kamar layin dogo mai sauƙi, bas na lantarki, jirgin ƙasa mai tafiya a ƙasa, da sauransu. Idan aka yi la'akari da cewa waɗannan ƙarfin suna da alaƙa da pantograph na locomotive ta hanyar pantograph, hulɗar da ke tsakanin pantograph da pantograph tana faruwa ne a lokacin tafiyar sufuri. Idan ba su da juna biyu, ana samun wutar lantarki ta hanyar capacitor tawada na DC-L, kuma lokacin da aka dawo da haɗin, ana samar da wutar lantarki mai yawa. Mafi munin yanayi shine cikakken fitarwa ta capacitor na DC-Link lokacin da aka cire haɗin, inda ƙarfin fitarwa ya yi daidai da ƙarfin pantograph, kuma lokacin da aka dawo da haɗin, sakamakon ƙarin ƙarfin lantarki ya kusan sau biyu na Un mai aiki. Ga capacitors na fim, ana iya sarrafa capacitor na DC-Link ba tare da ƙarin la'akari ba. Idan ana amfani da capacitors na electrolytic, ƙarfin lantarki mai yawa shine 1.2Un. Ɗauki metro na Shanghai a matsayin misali. Un=1500Vdc, don capacitor na electrolytic don la'akari da ƙarfin lantarki shine:

Sannan za a haɗa capacitors guda shida na 450V a jere. Idan ana amfani da ƙirar capacitor na fim a cikin 600Vdc zuwa 2000Vdc ko ma 3000Vdc, ana samun sauƙin cimmawa. Bugu da ƙari, makamashin da capacitor ke bayarwa gaba ɗaya yana samar da ɗan gajeren fitarwa tsakanin electrodes guda biyu, yana samar da babban wutar lantarki ta hanyar capacitor na DC-Link, wanda yawanci ya bambanta ga capacitors na electrolytic don biyan buƙatun.

Bugu da ƙari, idan aka kwatanta da masu ƙarfin lantarki na lantarki, ana iya tsara masu ƙarfin fim na DC-Link don cimma ƙarancin ESR (yawanci ƙasa da 10mΩ, har ma da ƙasa da <1mΩ) da kuma masu ƙarfin lantarki na LS (yawanci ƙasa da 100nH, kuma a wasu lokuta ƙasa da 10 ko 20nH). Wannan yana ba da damar shigar da mai ƙarfin lantarki na DC-Link kai tsaye cikin tsarin IGBT lokacin da aka yi amfani da shi, yana ba da damar haɗa sandar bas ɗin cikin mai ƙarfin lantarki na DC-Link, don haka yana kawar da buƙatar mai ƙarfin lantarki na IGBT na musamman lokacin amfani da masu ƙarfin lantarki na fim, wanda ke adana kuɗi mai yawa ga mai ƙira. Hoto na 2 da 3 sun nuna ƙayyadaddun fasaha na wasu samfuran C3A da C3B.

3. Kammalawa

A farkon zamanin, yawancin na'urorin DC-Link capacitors electrolytic ne saboda la'akari da farashi da girmansu.

Duk da haka, ƙarfin ƙarfin lantarki da ƙarfin juriya na lantarki suna shafar ƙarfin lantarki da ƙarfin juriya na yanzu (ESR mafi girma idan aka kwatanta da ƙarfin lantarki na fim), don haka ya zama dole a haɗa ƙarfin lantarki da yawa a jere da layi ɗaya don samun babban ƙarfin aiki da kuma biyan buƙatun amfani da babban ƙarfin lantarki. Bugu da ƙari, idan aka yi la'akari da canjin kayan lantarki, ya kamata a maye gurbinsa akai-akai. Sabbin aikace-aikacen makamashi gabaɗaya suna buƙatar rayuwar samfur na shekaru 15, don haka dole ne a maye gurbinsa sau 2 zuwa 3 a wannan lokacin. Saboda haka, akwai babban farashi da rashin jin daɗi a cikin sabis na bayan-tallace-tallace na gaba ɗaya na injin. Tare da haɓaka fasahar rufe ƙarfe da fasahar capacitor na fim, ya yiwu a samar da capacitors matattarar DC mai ƙarfi tare da ƙarfin lantarki daga 450V zuwa 1200V ko ma sama da haka tare da fim ɗin OPP mai siriri sosai (mafi siriri 2.7µm, har ma 2.4µm) ta amfani da fasahar vaporization fim mai aminci. A gefe guda kuma, haɗakar capacitors na DC-Link tare da sandar bas yana sa ƙirar module ɗin inverter ta fi ƙanƙanta kuma tana rage yawan inductance na da'irar don inganta da'irar.