Bekeng ena re tsoela pele ka sengoloa sa beke e fetileng.

1.2 Li-capacitor tsa electrolytic

Dielectric e sebelisoang ho electrolytic capacitors ke aluminium oxide e entsoeng ka ho bola ha aluminium, e nang le dielectric constant ea 8 ho ea ho 8.5 le matla a sebetsang a dielectric a ka bang 0.07V/A (1µm=10000A).Leha ho le joalo, ho ke ke ha khoneha ho finyella botenya bo joalo.Botenya ba lera la aluminium bo fokotsa matla a "capacitance" a electrolytic capacitor hobane foil ea aluminium e tlameha ho hlophisoa ho etsa filimi ea aluminium oxide ho fumana litšobotsi tse ntle tsa polokelo ea matla, 'me bokaholimo bo tla etsa libaka tse ngata tse sa lekaneng.Ka lehlakoreng le leng, resistivity ea electrolyte ke 150Ωcm bakeng sa voltage e tlase le 5kΩcm bakeng sa motlakase o phahameng (500V).Ho hanyetsa ho phahameng ha electrolyte ho fokotsa RMS ea hona joale eo electrolytic capacitor e ka mamellang, hangata ho 20mA/µF.

Ka lebaka la mabaka ana li-capacitor tsa electrolytic li etselitsoe bakeng sa matla a phahameng a 450V a tloaelehileng (baetsi ba bang ba moralo ba 600V).Ka hona, ho fumana li-voltage tse phahameng hoa hlokahala ho li fihlela ka ho hokahanya li-capacitor ka letoto.Leha ho le joalo, ka lebaka la phapang ea ho hanyetsa ha insulation ea capacitor e 'ngoe le e' ngoe ea electrolytic, mohanyetsi o tlameha ho hokeloa ho capacitor e 'ngoe le e' ngoe e le ho leka-lekanya matla a letoto le leng le le leng le amanang le capacitor.Ho feta moo, li-electrolytic capacitor ke lisebelisoa tse polarized, 'me ha motlakase o sebelisoang o feta makhetlo a 1.5 Un, ho etsahala karabelo ea electrochemic.Ha motlakase oa morao o sebelisitsoeng o le telele ka ho lekaneng, capacitor e tla tsoa.E le ho qoba ketsahalo ena, diode e lokela ho kopanngoa haufi le capacitor e 'ngoe le e' ngoe ha e sebelisoa.Ntle le moo, ho hanyetsa ha motlakase oa motlakase oa electrolytic capacitor hangata ke makhetlo a 1.15 Un, 'me tse ntle li ka fihla makhetlo a 1.2 Un.Kahoo baqapi ha baa lokela ho nahana feela ka motlakase o sebetsang o tsitsitseng empa hape le matla a ho phahama ha ba a sebelisa.Ka kakaretso, tafole e latelang ea papiso pakeng tsa li-capacitor tsa filimi le electrolytic capacitors e ka huloa, bona Fig.1.

2. Tlhahlobo ea Kopo

Li-capacitor tsa DC-Link e le li-filters li hloka meralo e phahameng ea hona joale le e phahameng.Mohlala ke mokhoa o ka sehloohong oa ho khanna koloi ea koloi e ncha ea matla joalokaha ho boletsoe ho Fig.3.Ts'ebetsong ena, capacitor e bapala karolo ea ho theola 'me potoloho e na le ts'ebetso e phahameng ea hona joale.Filimi ea DC-Link capacitor e na le molemo oa ho khona ho mamella maqhubu a maholo a sebetsang (Irms).Nka 50 ~ 60kW parameters ea koloi e ncha ea matla e le mohlala, mekhahlelo e tjena: motlakase o sebetsang 330 Vdc, ripple voltage 10Vrms, ripple current 150Arms@10KHz.

Ebe bonyane matla a motlakase a baloa joalo ka:

Sena se bonolo ho se sebelisa bakeng sa moralo oa capacitor ea filimi.Ho nka hore ho sebelisoa li-electrolytic capacitor, haeba ho nahanoa 20mA/μF, bonyane bokhoni ba li-electrolytic capacitor bo baloa ho fihlela liparamente tse kaholimo ka tsela e latelang:

Sena se hloka li-capacitor tse ngata tsa electrolytic tse hokahaneng ka tsela e tšoanang ho fumana bokhoni bona.

Lits'ebetsong tsa motlakase tse fetang matla, joalo ka terene e bobebe, bese ea motlakase, terene e tsamaeang ka tlas'a lefatše, joalo-joalo. Ha re nahana hore matla ana a hokahane le pantograph ea locomotive ka pantograph, khokahano lipakeng tsa pantograph le pantograph e etsahala nako le nako nakong ea leeto la lipalangoang.Ha tse peli li sa kopane, motlakase o tšehetsoa ke DC-L inki capacitor, 'me ha ho kopana ho tsosolosoa, ho hlahisoa ho feta-voltage.Nyeoe e mpe ka ho fetisisa ke ho tsoa ka ho feletseng ke DC-Link capacitor ha e khaotsoe, moo motlakase oa ho ntša motlakase o lekanang le motlakase oa pantograph, 'me ha ho kopana ho tsosolosoa, sephetho sa ho feta-voltage ke hoo e ka bang ka makhetlo a mabeli ho lekanngoa ho sebetsa Un.Bakeng sa li-capacitor tsa lifilimi, DC-Link capacitor e ka sebetsanoa ntle le ho nahana ka ho eketsehileng.Haeba ho sebelisoa li-electrolytic capacitor, matla a holimo ke 1.2Un.Nka mohlala oa metro ea Shanghai.Un=1500Vdc, bakeng sa capacitor ea electrolytic ho nahana ka motlakase ke:

Ebe li-capacitor tse tšeletseng tsa 450V li tla hokahanngoa ka letoto.Haeba moralo oa capacitor oa filimi o sebelisoa ho 600Vdc ho isa ho 2000Vdc kapa esita le 3000Vdc o fumaneha habonolo.Ho phaella moo, matla tabeng ea ho ntša capacitor ka ho feletseng e etsa hore ho be le nako e khutšoanyane ea potoloho pakeng tsa li-electrode tse peli, ho hlahisa motlakase o moholo oa motlakase ka DC-Link capacitor, eo hangata e fapaneng bakeng sa li-electrolytic capacitors ho finyella litlhoko.

Ho phaella moo, ha ho bapisoa le electrolytic capacitors DC-Link film capacitors e ka etsoa ho finyella ESR e tlaase haholo (hangata e ka tlaase ho 10mΩ, esita le ka tlaase ho <1mΩ) le LS ea boithati (hangata e ka tlase ho 100nH, 'me maemong a mang ka tlase ho 10 kapa 20nH) .Sena se lumella DC-Link filimi capacitor hore e kenngoe ka ho toba mojuleng oa IGBT ha e sebelisoa, ho lumella sebaka sa libese hore se kenngoe ho DC-Link filimi capacitor, kahoo ho felisa tlhokahalo ea IGBT absorber capacitor e inehetseng ha u sebelisa li-capacitor tsa filimi, ho boloka. moqapi chelete e ngata ea bohlokoa.Setšoantšo sa 2.mme 3 e bonts'a lintlha tsa tekheniki tsa tse ling tsa lihlahisoa tsa C3A le C3B.

3. Qetello

Matsatsing a pele, li-capacitor tsa DC-Link e ne e le li-electrolytic capacitor ka lebaka la litšenyehelo le boholo.

Leha ho le joalo, li-electrolytic capacitors li angoa ke matla a motlakase le a hona joale a mamellang (ESR e phahameng haholo ha e bapisoa le li-capacitor tsa filimi), kahoo hoa hlokahala ho hokahanya li-capacitor tse 'maloa tsa electrolytic ka letoto le ka tsela e tšoanang e le hore u fumane bokhoni bo boholo le ho finyella litlhoko tsa tšebeliso ea matla a phahameng.Ho phaella moo, ho nahana ka ho volatilization ea lisebelisoa tsa electrolyte, e lokela ho nkeloa sebaka kamehla.Lisebelisoa tse ncha tsa matla ka kakaretso li hloka bophelo ba sehlahisoa sa lilemo tse 15, kahoo e tlameha ho nkeloa sebaka ka makhetlo a 2 ho isa ho a 3 nakong ena.Ka hona, ho na le litšenyehelo tse ngata le tšitiso tšebeletsong ea morao-rao ea mochine oohle.Ka nts'etsopele ea theknoloji ea ho roala metallization le theknoloji ea capacitor ea filimi, ho khonne ho hlahisa li-capacitor tse phahameng tsa DC tse nang le voltage ho tloha 450V ho isa 1200V kapa ho feta ka filimi e tšesaane ea OPP (thinnest 2.7µm, esita le 2.4µm) e sebelisa theknoloji e sireletsehileng ea ho futhumatsa filimi.Ka lehlakoreng le leng, ho kopanngoa ha li-capacitor tsa DC-Link le bar ea libese ho etsa hore moralo oa mojule oa inverter o kopane le ho fokotsa haholo ho kheloha ha potoloho ho ntlafatsa potoloho.