N'izu a, anyị na-aga n'ihu na isiokwu nke izu gara aga.

1.2 Electrolytic capacitors

The dielectric eji na electrolytic capacitors bụ aluminum oxide kpụrụ site corrosion nke aluminum, na a dielectric mgbe nile nke 8 ka 8.5 na a na-arụ ọrụ dielectric ike nke banyere 0.07V/A (1µm=10000A).Otú ọ dị, ọ gaghị ekwe omume iji nweta oke dị otú ahụ.Ọkpụrụkpụ nke oyi akwa aluminom na-ebelata ikike ikike (ụfọdụ capacitance) nke electrolytic capacitors n'ihi na aluminom foil ga-etched na-emepụta ihe aluminom oxide film iji nweta ezi ike nchekwa àgwà, na elu ga-etolite ọtụtụ na-erughị eru na-ebupụta.N'aka nke ọzọ, resistivity nke electrolyte bụ 150Ωcm maka obere voltaji na 5kΩcm maka elu voltaji (500V).Nguzogide dị elu nke electrolyte na-amachi ikike RMS ugbu a nke ike electrolytic nwere ike idi, na-abụkarị 20mA/µF.

N'ihi ihe ndị a electrolytic capacitors e mere maka kacha voltaji nke 450V ahụkarị (ụfọdụ ndị na-emepụta onye na-emepụta maka 600V).Ya mere, iji nweta voltaji dị elu, ọ dị mkpa iji nweta ha site na ijikọ capacitors n'usoro.Otú ọ dị, n'ihi ọdịiche dị na mkpuchi mkpuchi nke onye ọ bụla electrolytic capacitor, a ga-ejikọta resistor na capacitor ọ bụla iji mee ka voltaji nke usoro ọ bụla jikọtara capacitor.Na mgbakwunye, electrolytic capacitors bụ ngwaọrụ polarized, na mgbe etinyere reverse voltaji gafere 1.5 ugboro Un, mmeghachi omume electrochemic na-apụta.Mgbe voltaji reverse etinyere ogologo oge, capacitor ga-awụfu.Iji zere ihe omume a, a ga-ejikọta diode n'akụkụ capacitor ọ bụla mgbe ejiri ya.E wezụga, voltaji na-eguzogide nguzogide nke electrolytic capacitors bụ n'ozuzu 1.15 ugboro Un, na ndị dị mma nwere ike iru 1.2 ugboro Un.Ya mere, ndị na-emepụta kwesịrị ịtụle ọ bụghị naanị voltaji na-arụ ọrụ nke ọma kamakwa voltaji na-agbapụta mgbe ị na-eji ha.Na nchịkọta, enwere ike ịdọrọ tebụl ntụnyere ndị a n'etiti ihe nkiri capacitors na electrolytic capacitors, lee Fig.1.

2. Ngwa nyocha

DC-Link capacitors dị ka ihe nzacha chọrọ atụmatụ dị ugbu a na ikike dị elu.Otu ihe atụ bụ isi moto mbanye usoro nke ọhụrụ ume ụgbọ dị ka ekwuru na Fig.3.N'ime ngwa a, capacitor na-arụ ọrụ nkedo na sekit nwere nnukwu ọrụ ugbu a.Ihe nkiri DC-Link capacitor nwere uru nke inwe ike iguzogide nnukwu mmiri na-arụ ọrụ (Irms).Were 50 ~ 60kW ọhụrụ ike ụgbọ ala dị ka ihe atụ, paramita bụ dị ka ndị a: arụ ọrụ voltaji 330 Vdc, ripple voltaji 10Vrms, ripple ugbu a 150Arms@10KHz.

Mgbe ahụ, a na-agbakọ ike eletrik kacha nta dị ka:

Nke a dị mfe maka mmejuputa maka imepụta ihe nkiri capacitor.Na-eche na a na-eji ndị na-eme ka electrolytic capacitors, ọ bụrụ na a na-atụle 20mA/μF, a na-agbakọ ike kacha nta nke ndị na-emepụta electrolytic iji mezuo ihe ndị dị n'elu dị ka ndị a:

Nke a na-achọ multiple electrolytic capacitors n'otu aka ahụ jikọọ iji nweta nke a capacitance.

N'ime ngwa voltaji karịa, dị ka ụgbọ oloko ọkụ, ụgbọ ala eletrik, ụzọ ụgbọ oloko, wdg. N'iburu n'uche na ejikọtara ike ndị a na pantograph locomotive site na pantograph, kọntaktị dị n'etiti pantograph na pantograph na-adịte aka n'oge njem njem.Mgbe ha abụọ na-adịghị na kọntaktị, ike ọkọnọ na-akwado site DC-L ink capacitor, na mgbe a na-eweghachi kọntaktị, n'elu-voltaji na-emepụta.Nke kacha njọ bụ npụpụ zuru oke site na DC-Link capacitor mgbe ọ kwụsịrị, ebe voltaji mwepu nhata na voltaji pantograph, na mgbe eweghachitere kọntaktị, ihe na-esi na voltaji pụta fọrọ nke nta ka ọ bụrụ okpukpu abụọ nke arụ ọrụ Un.Maka ndị na-emepụta ihe nkiri, DC-Link capacitor nwere ike ijikwa na-enweghị nlebara anya ọzọ.Ọ bụrụ na eji electrolytic capacitors, n'elu-voltaji bụ 1.2Un.Were Shanghai metro dị ka ihe atụ.Un=1500Vdc, maka electrolytic capacitor iji tụlee voltaji bụ:

Mgbe ahụ, a ga-ejikọta ndị isi 450V isii n'usoro.Ọ bụrụ na eji ihe nkiri capacitor imewe na 600Vdc ka 2000Vdc ma ọ bụ ọbụna 3000Vdc na-adị mfe nweta.Tụkwasị na nke ahụ, ike n'ihe gbasara ịgbasa capacitor n'ụzọ zuru ezu na-etolite mwepu sekit dị mkpirikpi n'etiti electrodes abụọ ahụ, na-emepụta nnukwu inrush ugbu a site na DC-Link capacitor, nke na-adịkarị iche maka ndị na-emepụta electrolytic iji mezuo ihe ndị a chọrọ.

Tụkwasị na nke ahụ, e jiri ya tụnyere electrolytic capacitors DC-Link film capacitors nwere ike ịmepụta iji nweta ESR dị ala (nke dị n'okpuru 10mΩ, na ọbụna ala <1mΩ) na ntinye onwe ya LS (nke dị n'okpuru 100nH, na n'ọnọdụ ụfọdụ n'okpuru 10 ma ọ bụ 20nH). .Nke a na-enye ohere ka etinyere capacitor ihe nkiri DC-Link ozugbo n'ime modul IGBT mgbe etinyere ya, na-enye ohere ka etinye ụgbọ ala ụgbọ ala n'ime ihe nkiri ihe nkiri DC-Link, si otú a na-ewepụ mkpa maka IGBT absorber capacitor raara onwe ya nye mgbe ị na-eji capacitors ihe nkiri, chekwaa. onye mmebe nnukwu ego.Fig.2.na 3 gosiputara nkọwa teknụzụ nke ụfọdụ ngwaahịa C3A na C3B.

3. Nkwubi okwu

N'oge mbụ, DC-Link capacitors na-abụkarị ndị na-ahụ maka electrolytic n'ihi ọnụ ahịa na nha nha.

Otú ọ dị, electrolytic capacitors na-emetụta voltaji na ugbu a iguzogide ike (ọtụtụ elu ESR tụnyere ihe nkiri capacitors), ya mere, ọ dị mkpa jikọọ ọtụtụ electrolytic capacitors na usoro na yiri ka iji nweta nnukwu ikike na izute chọrọ nke elu voltaji ojiji.Na mgbakwunye, na-atụle mgbanwe nke ihe electrolyte, a ga-edochi ya mgbe niile.Ngwa ike ọhụrụ na-achọkarị ndụ ngwaahịa nke afọ 15, yabụ, a ga-edochi ya ugboro 2 ruo 3 n'oge oge a.Ya mere, enwere ọnụ ahịa dị ukwuu na adịghị mma na ọrụ ire ere nke igwe dum.Site na mmepe nke teknụzụ mkpuchi metallization na teknụzụ capacitor ihe nkiri, ọ ga-ekwe omume ịmepụta ikike nzacha DC dị elu na voltaji sitere na 450V ruo 1200V ma ọ bụ karịa na ihe nkiri OPP dị oke mkpa (2.7µm kacha dị gịrịgịrị, ọbụlagodi 2.4µm) site na iji nchekwa ihe nkiri vaporization technology.N'aka nke ọzọ, njikọ nke DC-Link capacitors na ụgbọ ala ụgbọ ala na-eme ka modul inverter chepụta karịa kọmpat ma na-ebelata nke ukwuu inductance nke sekit iji kwalite sekit.