Kule veki siqhubeka nenqaku leveki ephelileyo.

1.2 I-Electrolytic capacitors

I-dielectric esetyenziswe kwi-electrolytic capacitors i-aluminium oxide eyenziwe yi-corrosion ye-aluminium, kunye ne-dielectric constant ye-8 ukuya kwi-8.5 kunye namandla asebenzayo e-dielectric malunga ne-0.07V / A (1µm = 10000A).Nangona kunjalo, akunakwenzeka ukufezekisa ubuninzi obunjalo.Ubunzima bomaleko we-aluminium bunciphisa umthamo we-capacitance (i-capacitance ethile) ye-electrolytic capacitors kuba ifoyile ye-aluminium kufuneka igxininiswe ukuze yenze ifilimu ye-aluminium oxide ukufumana iimpawu ezilungileyo zokugcina amandla, kwaye umphezulu uya kwenza iindawo ezininzi ezingalinganiyo.Kwelinye icala, ukuxhathisa kwe-electrolyte yi-150Ωcm kumbane ophantsi kunye ne-5kΩcm kumbane ophezulu (500V).Ukuxhathisa okuphezulu kwe-electrolyte kunciphisa i-RMS yangoku enokuthi i-electrolytic capacitor inokumelana nayo, ngokuqhelekileyo ukuya kwi-20mA/µF.

Ngezi zizathu ii-electrolytic capacitors ziyilelwe ubuninzi bombane obungama-450V eqhelekileyo (abanye abavelisi bayila i-600V).Ke ngoko, ukuze ufumane ii-voltages eziphezulu kufuneka uzifezekise ngokudibanisa ii-capacitors kuthotho.Nangona kunjalo, ngenxa yokwahlukana kwe-insulation resistance ye-electrolytic capacitor nganye, i-resistor kufuneka iqhagamshelwe kwi-capacitor nganye ukwenzela ukulinganisa i-voltage yochungechunge ngalunye oluxhunyiwe kwi-capacitor.Ukongezelela, i-electrolytic capacitors zixhobo ze-polarized, kwaye xa i-voltage ye-reverse esetyenzisiweyo idlula amaxesha angama-1.5 i-Un, i-electrochemic reaction iyenzeka.Xa i-voltage ye-reverse esetyenzisiweyo ide ngokwaneleyo, i-capacitor iya kuphalala.Ukuze ugweme le nto, i-diode kufuneka idibaniswe ecaleni kwe-capacitor nganye xa isetyenziswa.Ngaphandle koko, ukuxhathisa kokunyuka kombane we-electrolytic capacitors ngokuqhelekileyo yi-1.15 amaxesha e-Un, kwaye ezilungileyo zinokufikelela kwi-1.2 amaxesha e-Un.Ke abaqulunqi akufuneki bathathele ingqalelo kuphela amandla ombane asebenzayo kodwa kunye nombane wokutya xa uwasebenzisa.Isishwankathelo, itheyibhile yokuthelekisa ilandelayo phakathi kwefilimu yefilimu kunye ne-electrolytic capacitors inokutsalwa, jonga iFig.1.

2. Uhlalutyo lwesicelo

I-DC-Link capacitors njengoko izihluzi zifuna uyilo oluphezulu lwangoku kunye nomthamo ophezulu.Umzekelo yeyona nkqubo iphambili yokuqhuba isithuthi samandla esitsha njengoko kukhankanyiwe kwi-Fig.3.Kule sicelo i-capacitor idlala indima yokuqhawula kwaye isiphaluka sibonisa ukusebenza okuphezulu kwangoku.Ifilimu i-DC-Link capacitor inenzuzo yokukwazi ukumelana nemisinga enkulu yokusebenza (Irms).Thatha i-50 ~ 60kW iiparamitha zesithuthi samandla amatsha njengomzekelo, iiparamitha zimi ngolu hlobo lulandelayo: i-voltage yokusebenza 330 Vdc, i-ripple voltage 10Vrms, i-ripple current 150Arms@10KHz.

Emva koko ubuncinci umthamo wombane ubalwa ngolu hlobo:

Oku kulula ukuphunyezwa kuyilo lwefilimu ye-capacitor.Kucingelwa ukuba i-electrolytic capacitors isetyenzisiwe, ukuba i-20mA/μF iqwalaselwa, ubuncinci besakhono se-electrolytic capacitors ibalwa ukuhlangabezana nezi parameters zingentla ngolu hlobo lulandelayo:

Oku kufuna ii-electrolytic capacitors ezininzi ngokunxuseneyo ziqhagamshelwe ukufumana le capacitance.

Kwizicelo ze-over-voltage, ezifana ne-light rail, ibhasi yombane, i-subway, njl. Ukuqwalasela ukuba la magunya aqhagamshelwe kwi-pantograph ye-locomotive nge-pantograph, uqhagamshelwano phakathi kwepantograph kunye ne-pantograph luphazamiseka ngexesha lohambo lokuthutha.Xa ezi zimbini zingadibanisi, umbane uxhaswa yi-DC-L inki capacitor, kwaye xa umnxeba ubuyiselwa, i-over-voltage yenziwa.Imeko embi kakhulu ukukhutshwa okupheleleyo yi-DC-Link capacitor xa inqanyuliwe, apho i-voltage yokukhupha ilingana ne-voltage ye-pantograph, kwaye xa uqhagamshelwano lubuyiselwa, umphumo we-over-voltage uphantse uphindwe kabini ukulinganisa ukusebenza kwe-Un.Kwii-capacitors zefilimu i-DC-Link capacitor inokuphathwa ngaphandle kokuqwalaselwa okongeziweyo.Ukuba i-electrolytic capacitors isetyenzisiwe, i-over-voltage yi-1.2Un.Thatha umzekelo weMetro yaseShanghai.I-Un=1500Vdc, ye-electrolytic capacitor ukuqwalasela amandla ombane yile:

Emva koko ii-capacitors ze-450V ezintandathu kufuneka zixhunywe kuthotho.Ukuba uyilo lwe-filimi capacitor lusetyenziswa kwi-600Vdc ukuya kwi-2000Vdc okanye nakwi-3000Vdc lufumaneka lula.Ukongeza, amandla kwimeko yokukhupha ngokupheleleyo i-capacitor yenza ukukhutshwa kwesiphaluka esifutshane phakathi kwee-electrode ezimbini, ukuvelisa i-inrush yangoku enkulu nge-DC-Link capacitor, edla ngokuhlukileyo kwi-electrolytic capacitors ukuhlangabezana neemfuno.

Ukongezelela, xa kuthelekiswa ne-electrolytic capacitors DC-Link film capacitors inokuthi ilungiselelwe ukufezekisa i-ESR ephantsi kakhulu (ngokuqhelekileyo ingaphantsi kwe-10mΩ, kwaye iphantsi <1mΩ) kunye ne-self-inductance LS (ngokuqhelekileyo ingaphantsi kwe-100nH, kwaye kwezinye iimeko ngaphantsi kwe-10 okanye i-20nH) .Oku kuvumela i-DC-Link ifilimu capacitor ukuba ifakwe ngqo kwimodyuli ye-IGBT xa isetyenzisiwe, ivumela ibha yebhasi ukuba idibaniswe kwi-DC-Link ifilimu ye-capacitor, ngaloo ndlela isusa isidingo se-IGBT absorber capacitor ezinikeleyo xa usebenzisa i-filimi capacitors, ukonga. umyili imali ebalulekileyo.Isazobe.2.kwaye i-3 ibonisa iinkcukacha zobugcisa zezinye zeemveliso ze-C3A kunye ne-C3B.

3. Isiphelo

Kwiintsuku zokuqala, i-DC-Link capacitors yayiyi-electrolytic capacitors ngenxa yeendleko kunye nobukhulu bengqwalasela.

Nangona kunjalo, i-electrolytic capacitors ichaphazeleka ngamandla ombane kunye nokumelana kwangoku (i-ESR ephezulu kakhulu xa kuthelekiswa nefilim capacitors), ngoko ke kuyimfuneko ukudibanisa i-electrolytic capacitors ezininzi kuthotho kunye nokuhambelana ukuze kufumaneke umthamo omkhulu kunye nokuhlangabezana neemfuno zokusetyenziswa kombane ophezulu.Ukongezelela, ukuqwalasela ukuguqulwa kwezinto ze-electrolyte, kufuneka kuthathelwe indawo rhoqo.Ukusetyenziswa kwamandla amatsha ngokubanzi kufuna ubomi bemveliso yeminyaka eyi-15, ngoko kufuneka kutshintshwe amaxesha ama-2 ukuya kwe-3 ngeli xesha.Ke ngoko, kukho iindleko ezinkulu kunye nokuphazamiseka kwinkonzo yasemva kokuthengiswa komatshini wonke.Ngophuhliso lwetekhnoloji yokugquma i-metallization kunye neteknoloji ye-capacitor yefilimu, kube nokwenzeka ukuvelisa i-DC ye-filter capacitors ekumgangatho ophezulu ngamandla ombane ukusuka kwi-450V ukuya kwi-1200V okanye nangaphezulu ngefilimu ye-OPP ecwecwe kakhulu (eyona thinnest 2.7µm, ne-2.4µm) kusetyenziswa itekhnoloji yokhuseleko lokutshisa ifilimu.Ngakolunye uhlangothi, ukudityaniswa kwe-DC-Link capacitors kunye nebhasi yebhasi kwenza imodyuli ye-inverter yoyilo idityaniswe ngakumbi kwaye inciphisa kakhulu i-inductance elahlekileyo yesekethe ukuze kulungiswe isiphaluka.