Kule veki siyaqhubeka nenqaku leveki ephelileyo.

1.2 Ii-capacitor ze-electrolytic

I-dielectric esetyenziswa kwi-electrolytic capacitors yi-aluminium oxide eyenziwe kukubola kwe-aluminium, ene-dielectric constant eyi-8 ukuya kwi-8.5 kunye namandla e-dielectric asebenzayo amalunga ne-0.07V/A (1µm=10000A). Nangona kunjalo, akunakwenzeka ukufikelela kubukhulu obunjalo. Ubukhulu bomaleko we-aluminium bunciphisa i-capacity factor (i-capacitance ethile) yee-electrolytic capacitors kuba i-aluminium foil kufuneka ikrolwe ukuze kwenziwe ifilimu ye-aluminium oxide ukuze kufunyanwe iimpawu ezilungileyo zokugcina amandla, kwaye umphezulu uya kwenza iindawo ezininzi ezingalinganiyo. Kwelinye icala, i-resistivity ye-electrolyte yi-150Ωcm kwi-voltage ephantsi kunye ne-5kΩcm kwi-voltage ephezulu (500V). I-resistivity ephezulu ye-electrolyte ithintela i-RMS current enokumelana nayo i-electrolytic capacitor, ngokuqhelekileyo ukuya kwi-20mA/µF.

Ngenxa yezi zizathu ii-capacitors ze-electrolytic zenzelwe i-voltage ephezulu ye-450V eqhelekileyo (abanye abavelisi bayila i-600V). Ke ngoko, ukuze kufumaneke ii-voltage eziphezulu kufuneka zifezekiswe ngokudibanisa ii-capacitors ngokulandelelana. Nangona kunjalo, ngenxa yomahluko ekuchaseni kwe-insulation ye-capacitor nganye ye-electrolytic, i-resistor kufuneka iqhagamshelwe kwi-capacitor nganye ukuze ilinganise i-voltage ye-capacitor nganye eqhagamshelweyo. Ukongeza, ii-capacitors ze-electrolytic zizixhobo ezi-polarized, kwaye xa i-voltage ebuyela umva esetyenzisiweyo idlula i-1.5 times Un, kwenzeka i-electrochemic reaction. Xa i-voltage ebuyela umva esetyenzisiweyo inde ngokwaneleyo, i-capacitor iya kuphalala. Ukuze kuthintelwe le meko, i-diode kufuneka iqhagamshelwe ecaleni kwe-capacitor nganye xa isetyenziswa. Ngaphandle koko, i-voltage surge resistance yee-capacitors ze-electrolytic ngokubanzi yi-1.15 times Un, kwaye ezilungileyo zinokufikelela kwi-1.2 times Un. Ngoko ke abayili akufuneki baqwalasele i-voltage yokusebenza eqinileyo kuphela kodwa kunye ne-surge voltage xa ​​beyisebenzisa. Ngamafutshane, itheyibhile elandelayo yokuthelekisa phakathi kwee-capacitors zefilimu kunye nee-capacitors ze-electrolytic ingazotywa, jonga uMfanekiso 1.

2. Uhlalutyo lweSicelo

Ii-capacitor ze-DC-Link njengezihluzi zifuna uyilo lwamandla aphezulu kunye nolwe-capacity ephezulu. Umzekelo yinkqubo ephambili yokuqhuba imoto yesithuthi esitsha samandla njengoko kukhankanyiwe kuMfanekiso 3. Kolu setyenziso, i-capacitor idlala indima yokudibanisa kwaye isekethe inomsinga osebenzayo ophezulu. I-capacitor yefilimu ye-DC-Link inenzuzo yokukwazi ukumelana nemisinga emikhulu yokusebenza (ii-Irms). Thatha iiparameter zesithuthi esitsha samandla ezingama-50~60kW njengomzekelo, iiparameter zezi zilandelayo: i-voltage yokusebenza eyi-330 Vdc, i-voltage ye-ripple eyi-10Vrms, i-ripple current eyi-150Arms@10KHz.

Emva koko amandla ombane aphantsi abalwa ngolu hlobo:

Oku kulula ukukusebenzisa kuyilo lwe-capacitor yefilimu. Ukuba kusetyenziswa ii-capacitor ze-electrolytic, ukuba kucingelwa i-20mA/μF, ubuncinci be-capacitance yee-capacitors ze-electrolytic bubalwa ukuhlangabezana nezi parameters zingasentla ngolu hlobo lulandelayo:

Oku kufuna ii-capacitor ezininzi ze-electrolytic ezidityanisiweyo ngaxeshanye ukuze kufunyanwe olu capacitance.

Kwizicelo ze-over-voltage, ezifana ne-light rail, ibhasi yombane, i-subway, njl. Xa ucinga ukuba la mandla aqhagamshelwe kwi-locomotive pantograph nge-pantograph, unxibelelwano phakathi kwe-pantograph kunye ne-pantograph luhlala luqhagamshelwe ngexesha lokuhamba ngezithuthi. Xa ezi zimbini zingadibani, umbane uxhaswa yi-DC-L ink capacitor, kwaye xa unxibelelwano lubuyiselwa, i-over-voltage iveliswa. Imeko embi kakhulu kukukhupha ngokupheleleyo yi-DC-Link capacitor xa iqhagamshelwe, apho i-discharge voltage ilingana ne-pantograph voltage, kwaye xa unxibelelwano lubuyiselwa, i-over-voltage ephumayo iphantse ibe kabini kune-Un esebenzayo elinganisiweyo. Kwii-capacitors zefilimu, i-DC-Link capacitor inokuphathwa ngaphandle kokuqwalaselwa okongezelelweyo. Ukuba kusetyenziswa ii-capacitors ze-electrolytic, i-over-voltage yi-1.2Un. Thatha i-Shanghai metro njengomzekelo. I-Un=1500Vdc, kwi-electrolytic capacitor ukuqwalasela i-voltage yile:

Emva koko ii-capacitor ezintandathu ze-450V kufuneka ziqhagamshelwe ngokulandelelana. Ukuba uyilo lwe-capacitor yefilimu lusetyenziswa kwi-600Vdc ukuya kwi-2000Vdc okanye nakwi-3000Vdc kulula ukuyifumana. Ukongeza, amandla xa ekhutshwa ngokupheleleyo i-capacitor enza ukukhutshwa kwesekethe emfutshane phakathi kwee-electrodes ezimbini, okuvelisa umsinga omkhulu wokungena nge-DC-Link capacitor, odla ngokwahluka kwii-capacitor ze-electrolytic ukuhlangabezana neemfuno.

Ukongeza, xa kuthelekiswa nee-capacitors ze-electrolytic, ii-capacitors zefilimu ze-DC-Link zinokuyilwa ukuze zifezekise i-ESR ephantsi kakhulu (ngesiqhelo ingaphantsi kwe-10mΩ, kwaye ingaphantsi kwe-<1mΩ) kunye ne-self-inductance LS (ngesiqhelo ingaphantsi kwe-100nH, kwaye kwezinye iimeko ingaphantsi kwe-10 okanye i-20nH). Oku kuvumela i-capacitor yefilimu ye-DC-Link ukuba ifakwe ngqo kwi-module ye-IGBT xa isetyenziswa, okuvumela ukuba ibha yebhasi ifakwe kwi-capacitor yefilimu ye-DC-Link, ngaloo ndlela kususa imfuneko ye-capacitor ye-absorber ye-IGBT ezinikeleyo xa kusetyenziswa ii-capacitors zefilimu, okonga umyili imali eninzi. Umfanekiso 2. kunye no-3 ubonisa iinkcukacha zobugcisa zezinye zeemveliso ze-C3A kunye ne-C3B.

3. Isiphelo

Kwimihla yokuqala, ii-capacitors ze-DC-Link zazizii-capacitors ze-electrolytic ngenxa yeendleko kunye nobungakanani.

Nangona kunjalo, ii-capacitors ze-electrolytic zichaphazeleka kubuchule bokumelana ne-voltage kunye nombane (i-ESR ephezulu kakhulu xa ithelekiswa nee-capacitors zefilimu), ngoko ke kuyimfuneko ukuqhagamshela ii-capacitors ezininzi ze-electrolytic ngokulandelelana kunye nangokwexesha elifanayo ukuze kufunyanwe umthamo omkhulu kwaye kuhlangatyezwane neemfuno zokusetyenziswa kwe-voltage ephezulu. Ukongeza, xa kujongwa ukuguquguquka kwezinto ze-electrolyte, kufuneka zitshintshwe rhoqo. Ukusetyenziswa kwamandla amatsha ngokubanzi kufuna ubomi bemveliso beminyaka eli-15, ngoko ke kufuneka itshintshwe amaxesha ama-2 ukuya kwama-3 ngeli xesha. Ke ngoko, kukho iindleko ezinkulu kunye nokuphazamiseka kwinkonzo yasemva kokuthengisa yomatshini wonke. Ngophuhliso lwetekhnoloji yokugquma i-metallization kunye netekhnoloji ye-capacitor yefilimu, kuye kwenzeka ukuvelisa ii-capacitors ze-DC filter ezinomthamo ophezulu ezine-voltage ukusuka kwi-450V ukuya kwi-1200V okanye ngaphezulu ngefilimu ye-OPP encinci kakhulu (eyona 2.7µm incinci, nokuba yi-2.4µm) kusetyenziswa itekhnoloji yokukhusela i-vaporization yefilimu. Kwelinye icala, ukudityaniswa kwee-capacitors ze-DC-Link kunye nebha yebhasi kwenza uyilo lwe-inverter module lube ncinci ngakumbi kwaye kunciphisa kakhulu i-inductance elahlekileyo yesekethe ukuze kuphuculwe isekethe.