Sabata ino tikupitiliza ndi nkhani ya sabata yatha.

1.2 Electrolytic capacitors

Ma dielectric omwe amagwiritsidwa ntchito mu electrolytic capacitors ndi aluminiyamu okusayidi yopangidwa ndi dzimbiri la aluminiyamu, yokhala ndi dielectric yokhazikika ya 8 mpaka 8.5 ndi mphamvu ya dielectric yogwira ntchito pafupifupi 0.07V/A (1µm=10000A).Komabe, sizingatheke kukwaniritsa makulidwe oterowo.Makulidwe a aluminiyamu wosanjikiza amachepetsa mphamvu yamagetsi (capacitance yeniyeni) ya ma electrolytic capacitors chifukwa chojambula cha aluminiyamu chiyenera kukhazikitsidwa kuti apange filimu ya aluminium oxide kuti apeze makhalidwe abwino osungira mphamvu, ndipo pamwamba pake padzakhala malo ambiri osagwirizana.Komano, resistivity wa electrolyte ndi 150Ωcm kwa voteji otsika ndi 5kΩcm kwa voteji mkulu (500V).Kulimbana kwakukulu kwa electrolyte kumalepheretsa RMS panopa yomwe electrolytic capacitor imatha kupirira, nthawi zambiri mpaka 20mA/µF.

Pazifukwa izi ma electrolytic capacitors adapangidwa kuti apange voteji pazipita 450V mmene (ena opanga munthu kupanga 600V).Chifukwa chake, kuti mupeze ma voltages apamwamba ndikofunikira kuti muwakwaniritse polumikiza ma capacitor angapo.Komabe, chifukwa cha kusiyana kwa kutchinjiriza kukana kwa electrolytic capacitor iliyonse, chotsutsa chiyenera kulumikizidwa ku capacitor iliyonse kuti muzitha kuwongolera voteji yamtundu uliwonse wolumikizidwa.Kuphatikiza apo, ma electrolytic capacitors ndi zida za polarized, ndipo voteji yomwe imagwiritsidwa ntchito ikapitilira nthawi 1.5 Uni, electrochemic reaction imachitika.Pamene magetsi ogwiritsidwa ntchito akutalika mokwanira, capacitor idzatuluka.Pofuna kupewa chodabwitsa ichi, diode iyenera kulumikizidwa pafupi ndi capacitor iliyonse ikagwiritsidwa ntchito.Kupatula apo, kukana kwamphamvu kwa ma electrolytic capacitor nthawi zambiri kumakhala nthawi 1.15 Un, ndipo zabwino zimatha kufika nthawi 1.2 pa Un.Chifukwa chake okonzawo sayenera kungoganizira za mphamvu yogwira ntchito yosasunthika komanso mphamvu yamagetsi owonjezera akamagwiritsa ntchito.Mwachidule, tebulo lofanizira lotsatirali pakati pa ma capacitors a filimu ndi electrolytic capacitors akhoza kukokedwa, onani Fig.1.

2. Kusanthula Ntchito

Ma capacitor a DC-Link monga zosefera amafunikira mapangidwe apamwamba komanso apamwamba.Chitsanzo ndi njira yayikulu yoyendetsera galimoto yamagetsi atsopano monga momwe tafotokozera mkuyu.3.Pogwiritsa ntchito izi, capacitor imagwira ntchito yochepetsera ndipo dera limakhala ndi mphamvu yogwira ntchito kwambiri.Filimu ya DC-Link capacitor ili ndi mwayi wokhoza kupirira mafunde akuluakulu ogwiritsira ntchito (Irms).Tengani 50 ~ 60kW magawo a galimoto yamagetsi atsopano monga chitsanzo, magawowa ndi awa: voteji yogwiritsira ntchito 330 Vdc, ripple voltage 10Vrms, ripple current 150Arms@10KHz.

Ndiye mphamvu yamagetsi yocheperako imawerengedwa motere:

Izi ndizosavuta kugwiritsa ntchito kupanga filimu capacitor.Pongoganiza kuti ma electrolytic capacitor amagwiritsidwa ntchito, ngati 20mA/μF imaganiziridwa, mphamvu yochepera ya ma electrolytic capacitors imawerengedwa kuti ikwaniritse magawo omwe ali pamwambapa motere:

Izi zimafuna ma electrolytic capacitor angapo molumikizana olumikizidwa kuti apeze mphamvu iyi.

Muzowonjezera mphamvu zamagetsi, monga njanji yopepuka, basi yamagetsi, njanji yapansi panthaka, ndi zina zotero. Poganizira kuti mphamvuzi zimagwirizanitsidwa ndi locomotive pantograph kudzera pa pantograph, kukhudzana pakati pa pantograph ndi pantograph kumakhala kwapakati paulendo wapaulendo.Pamene awiriwa sakulumikizana, magetsi amathandizidwa ndi DC-L inki capacitor, ndipo pamene kukhudzana kwabwezeretsedwa, mphamvu yowonjezera imapangidwa.Choyipa kwambiri ndi kutulutsa kwathunthu ndi DC-Link capacitor ikalumikizidwa, pomwe kutulutsa voteji ndi kofanana ndi voteji ya pantograph, ndipo kukhudzana ndi kubwezeretsedwanso, chifukwa cha-voltage ndi pafupifupi kuwirikiza kawiri kuposa ovotera Un.Kwa ma capacitor a filimu DC-Link capacitor imatha kuyendetsedwa popanda kuganizira zina.Ngati ma electrolytic capacitors agwiritsidwa ntchito, mphamvu yowonjezera ndi 1.2Un.Tengani chitsanzo cha metro ya Shanghai.Un=1500Vdc, kuti electrolytic capacitor kuganizira voteji ndi:

Ndiye ma capacitor asanu ndi limodzi a 450V ayenera kulumikizidwa mndandanda.Ngati filimu ya capacitor ikugwiritsidwa ntchito mu 600Vdc mpaka 2000Vdc kapena ngakhale 3000Vdc imatheka mosavuta.Kuphatikiza apo, mphamvu pakutulutsa kwathunthu capacitor imapanga kukhetsa kwafupipafupi pakati pa maelekitirodi awiri, kutulutsa mphamvu yayikulu yolowera kudzera pa DC-Link capacitor, yomwe nthawi zambiri imakhala yosiyana ndi ma electrolytic capacitors kuti akwaniritse zofunikira.

Kuphatikiza apo, poyerekeza ndi ma electrolytic capacitors DC-Link film capacitors amatha kupangidwa kuti akwaniritse ESR yotsika kwambiri (nthawi zambiri pansi pa 10mΩ, komanso ngakhale kutsika <1mΩ) ndi kudziletsa LS (nthawi zambiri pansi pa 100nH, ndipo nthawi zina pansi pa 10 kapena 20nH) .Izi zimathandiza kuti DC-Link film capacitor ikhazikitsidwe molunjika mu module ya IGBT ikagwiritsidwa ntchito, kulola kuti bar ya basi ikhale yophatikizidwa mu DC-Link film capacitor, motero kuchotsa kufunikira kwa IGBT absorber capacitor yodzipatulira pamene mukugwiritsa ntchito filimu capacitors, kupulumutsa. wopanga ndalama zambiri.Chithunzi 2.ndi 3 akuwonetsa ukadaulo wazinthu zina za C3A ndi C3B.

3. Mapeto

M'masiku oyambirira, ma capacitor a DC-Link anali makamaka ma electrolytic capacitors chifukwa cha mtengo ndi kukula kwake.

Komabe, ma electrolytic capacitors amakhudzidwa ndi mphamvu yamagetsi komanso kupirira kwapano (ESR yokwera kwambiri poyerekeza ndi ma capacitors a filimu), kotero ndikofunikira kulumikiza ma capacitor angapo a electrolytic motsatizana komanso mofananira kuti apeze mphamvu yayikulu ndikukwaniritsa zofunikira pakugwiritsa ntchito ma voliyumu apamwamba.Komanso, poganizira volatilization wa zinthu electrolyte, ayenera m'malo nthawi zonse.Kugwiritsa ntchito mphamvu zatsopano nthawi zambiri kumafunikira moyo wazinthu zaka 15, motero ziyenera kusinthidwa 2 mpaka 3 nthawi imeneyi.Chifukwa chake, pali ndalama zambiri komanso zosokoneza pakugulitsa pambuyo pa makina onse.Ndi chitukuko chaukadaulo wazitsulo zokutira ndi ukadaulo wa filimu capacitor, zatheka kupanga ma capacitor apamwamba kwambiri a DC okhala ndi magetsi kuchokera ku 450V mpaka 1200V kapena kupitilira apo ndi filimu yowonda kwambiri ya OPP (thinnest 2.7µm, ngakhale 2.4µm) kugwiritsa ntchito chitetezo filimu vaporization luso.Kumbali inayi, kuphatikiza kwa ma capacitor a DC-Link ndi bar ya basi kumapangitsa kapangidwe ka module ya inverter kukhala yaying'ono komanso kumachepetsa kwambiri kusokonekera kwa dera kuti kukhathamiritse dera.