Umhlinzeki weyunithi ye-frequency converter braking unit ukukhumbuza ukuthi kokubili uhlobo lwamanje kanye neziguquli zohlobo lwe-voltage zingezabaguquli befrikhwensi be-AC-DC-AC, okuhlanganisa isilungisi kanye nesiguquli.
Ngenxa yokuthi imithwalo ngokuvamile iyashintsha, kufanele kube nokudluliswa kwamandla okusebenzayo phakathi kwemithombo yawo yamandla. Ngakho-ke, kusixhumanisi esimaphakathi se-DC, kunesidingo sezingxenye zokuvikela amandla asebenzayo.
Uma i-capacitor enkulu isetshenziselwa ukuvimba amandla asebenzayo, ihlanganisa isiguquli semvamisa yohlobo lomthombo we-voltage; Uma i-reactor enkulu isetshenziselwa ukugcina ibhafa amandla asebenzayo, ihlanganisa isiguquli sefrikhwensi yohlobo lwamanje lomthombo.
Umehluko phakathi kweziguquli zefrikhwensi yohlobo lwe-voltage kanye neziguquli zefrikhwensi yohlobo lwamanje usesimweni kuphela sesihlungi sesixhumanisi se-DC esimaphakathi. Nokho, lokhu kubangela umehluko omkhulu wokusebenza phakathi kwezinhlobo ezimbili zeziguquli zemvamisa, njengoba kuboniswe ohlwini olulandelayo lokuqhathanisa:
1. Izingxenye zokugcina amandla: uhlobo lwe-voltage frequency converter - capacitor; Uhlobo lwamanje - i-reactor.
2. Izici ze-waveform okukhiphayo: I-voltage waveform iyigagasi elingunxande, i-waveform yamanje icishe ibe yi-sine wave; Isiguquli sefrikhwensi yohlobo lwamanje sinesimo segagasi esingunxande samanje kanye nefomu legagasi le-sine elilinganiselwe le-voltage
3. Izici zokwakheka kwesekethe zifaka phakathi i-feedback diode DC amandla kagesi ngokuhambisana nomthamo omkhulu we-capacitor (umthombo wamandla aphansi we-impedance voltage) njengohlobo lwe-voltage; Uhlobo lwamanje olunikezwa amandla we-DC non-feedback diode ochungechungeni eline-inductance enkulu (umthombo wamanje we-impedance ephezulu) lwenza kube lula ukuthi injini isebenze ngamaquadrants amane.
4. Ngokwezici, uhlobo lwe-voltage lukhiqiza i-overcurrent lapho umthwalo ufinyezwa, futhi ama-open-loop motors nawo angasebenza ngokuzinzile; Uhlobo lwamanje lungacindezela i-overcurrent lapho umthwalo ufinyezwa, futhi ukulawulwa kwempendulo kuyadingeka ekusebenzeni okungazinzile kwemoto.
Iziguquli zamanje zomthombo zisebenzisa ama-thyristors ashintshiwe ngokwemvelo njengamaswishi kagesi, ane-DC side inductance ebizayo futhi asetshenziswa ekulawuleni isivinini esiphakelwa kabili. Adinga amasekhethi okushintsha ngesivinini esihambisanayo futhi abe nokusebenza okungalungile kumaza okushelela aphansi.
Izici zesakhiwo se-frequency converter
Isixhumanisi se-DC sohlobo lwamanje lwe-frequency converter siqanjwe ngemuva kokusetshenziswa kwezingxenye ze-inductive, esinenzuzo yamandla okusebenza ama-quadrant amane futhi singafinyelela kalula umsebenzi wokubhuleka wemoto. Okubi ukuthi kudinga ukushintshwa okuphoqelelwe kwebhuloho le-inverter, futhi isakhiwo sedivayisi siyinkimbinkimbi, okwenza ukulungisa kube nzima. Ngaphezu kwalokho, ngenxa yokusetshenziswa kwe-thyristor phase-shifting rectification ohlangothini lwegridi yamandla, ama-harmonics wamanje okokufaka makhulu ngokuqhathaniswa, azoba nomthelela othile kugridi yamandla lapho umthamo mkhulu.
2. Isiguquli sohlobo lwe-voltage frequency siqanjwe ngemuva kokusetshenziswa kwezingxenye ze-capacitive kusixhumanisi se-DC sesiguquli sefrikhwensi. Isici sayo ukuthi ayikwazi ukusebenza ngama-quadrants amane. Lapho imoto yomthwalo idinga ukubhuleka, isifunda sokubhuleka esihlukile sidinga ukufakwa. Uma amandla ephezulu, isihlungi se-sine wave sidinga ukungezwa kokuphumayo.
3. Isiguquli sefrikhwensi yamanje ephezulu sisebenzisa i-GTO, SCR noma izingxenye ze-IGCT ochungechungeni ukuze kuzuzwe ukuguqulwa okuqondile kwe-voltage high-voltage, nge-voltage yamanje efika ku-10KV. Ngenxa yokusetshenziswa kwezingxenye ze-inductive kusixhumanisi se-DC, ayizwelani ngokwanele namanje, okuyenza ingajwayeleki kakhulu kumaphutha adlulele. I-inverter nayo inokwethenjelwa ekusebenzeni futhi inokusebenza okuhle kokuvikela. Uhlangothi okokufaka lusebenzisa ukulungiswa okulawulwayo kwesigaba se-thyristor, futhi ama-harmonics wamanje okufakwayo makhulu uma kuqhathaniswa. Uma umthamo wesiguquli sefrikhwensi mkhulu, ukungcoliswa kwegridi yamandla kanye nokuphazamiseka kokusebenza kwemishini kagesi yokuxhumana kufanele kucatshangelwe. Ukulinganisa kwamandla kagesi kanye nesekhethi yebhafa kuyinkimbinkimbi ngokobuchwepheshe futhi kuyabiza. Ngenxa yenani elikhulu lezingxenye nevolumu yedivayisi, ukulungisa nokugcinwa kunzima. Ibhuloho le-inverter lamukela ukuguqulwa okuphoqelekile futhi likhiqize ukushisa okukhulu, okudinga ukuxazulula inkinga yokukhishwa kokushisa kwezingxenye. Inzuzo yayo isemandleni ayo okusebenza ngama-quadrants amane namabhuleki. Kumele kuqashelwe ukuthi lolu hlobo lwe-frequency converter ludinga ukufakwa kwe-high-voltage self-healing capacitor emaceleni alo okufakwayo nokukhishwayo ngenxa yesici sawo samandla aphansi okufakwayo kanye ne-harmonics ephezulu yokufaka nokukhipha.
4. Isakhiwo sesifunda se-high-voltage inverter samukela ubuchwepheshe bochungechunge oluqondile lwe-IGBT, owaziwa nangokuthi uchungechunge lwedivayisi eqondile inverter ephezulu ye-voltage. Isebenzisa ama-capacitor anamandla kagesi aphezulu ukuhlunga nokugcina amandla kusixhumanisi se-DC, ne-voltage ephumayo efika ku-6KV. Inzuzo yayo ukuthi ingasebenzisa amadivayisi amelana ne-voltage aphansi, futhi wonke ama-IGBT ongalo yebhuloho lochungechunge anomsebenzi ofanayo, onika amandla ukwenza isipele okuhlangene noma ukuklama okungafuneki. Okubi ukuthi inani lamazinga liphansi uma kuqhathaniswa, amazinga amabili kuphela, futhi i-voltage ephumayo i-dV/dt nayo inkulu, idinga ukusetshenziswa kwamamotho akhethekile noma izihlungi ze-sine wave wave, ezizonyusa izindleko kakhulu. Ayinawo umsebenzi wokusebenza wama-quadrant amane, futhi iyunithi yokubhuleka ehlukile idinga ukufakwa ngesikhathi sokubhuleka. Lolu hlobo lwesiguquli se-frequency ludinga futhi ukuxazulula inkinga yokulinganisa amandla kagesi wedivayisi, ngokuvamile okudinga ukwakheka okukhethekile kwamasekhethi okushayela kanye namasekhethi ebhafa. Kukhona futhi nezidingo eziqinile kakhulu zokubambezeleka kwamasekethe okushayela e-IGBT. Uma izikhathi zokuvula nokuvala ze-IGBT zingahambisani, noma imiphetho yamaphethelo akhuphukayo nawayo ehluke kakhulu, kuzodala umonakalo kumadivayisi kagesi.
Kunezinhlobo eziningi zama-inverter ane-voltage ephezulu, futhi izindlela zabo zokuhlukanisa nazo zihlukile. Ngokusho kokuthi kukhona ingxenye ye-DC kusixhumanisi esiphakathi, ingahlukaniswa ngama-converter ama-frequency we-AC/AC kanye nama-frequency converters e-AC-DC-AC; Ngokwezakhiwo zengxenye ye-DC, ingahlukaniswa ngohlobo lwamanje kanye neziguquli zohlobo lwe-voltage.
Isiguquli sohlobo lwamanje
Iqanjwe ngemuva kokusetshenziswa kwezingxenye ze-inductive kusixhumanisi se-DC se-frequency converter, inenzuzo yamandla okusebenza ama-quadrant amane futhi ingafinyelela kalula umsebenzi wokubhuleka wenjini. Okubi ukuthi kudinga ukushintshwa okuphoqelelwe kwebhuloho le-inverter, futhi isakhiwo sedivayisi siyinkimbinkimbi, okwenza ukulungisa kube nzima. Ngaphezu kwalokho, ngenxa yokusetshenziswa kokulungiswa kokuguqulwa kwesigaba se-thyristor ohlangothini lwegridi yamandla, ama-harmonics wamanje okufakwayo makhulu ngokuqhathaniswa, azoba nomthelela othile kugridi yamandla uma umthamo mkhulu.
Uhlobo lwe-Voltage frequency converter
Iqanjwe ngemuva kokusetshenziswa kwezingxenye ze-capacitive kusixhumanisi se-DC se-converter frequency, isici sayo ukuthi ayikwazi ukusebenza ngama-quadrants amane. Lapho imoto yomthwalo idinga ukubhuleka, isifunda sokubhuleka esihlukile sidinga ukufakwa. Uma amandla ephezulu, isihlungi se-sine wave sidinga ukungezwa kokuphumayo.
1. Uyini umehluko phakathi kohlobo lwe-voltage kanye nohlobo lwamanje?
Isifunda esiyinhloko se-converter ye-frequency singahlukaniswa cishe ngezigaba ezimbili: uhlobo lwe-voltage luyi-converter ye-frequency eguqula i-DC yomthombo we-voltage ibe yi-AC, futhi ukuhlunga kwesifunda se-DC kuyi-capacitor; Uhlobo lwamanje yisiguquli semvamisa esiguqula i-DC yomthombo wamanje ibe yi-AC, futhi isihlungi sayo sesekethe ye-DC siyi-inductor.
2. Kungani i-voltage ne-current yesiguquli se-frequency ishintsha ngokulinganayo?
I-torque ye-asynchronous motor ikhiqizwa ukuxhumana phakathi kwe-flux kazibuthe ye-motor kanye ne-current egeleza ku-rotor. Ku-frequency elinganiselwe, uma i-voltage ingaguquki futhi imvamisa kuphela iyancipha, i-flux kazibuthe izoba nkulu kakhulu, isifunda kazibuthe sizogcwala, futhi ezimeni ezinzima, injini izoshiswa. Ngakho-ke, i-frequency kanye ne-voltage kufanele kushintshwe ngokulinganayo, okungukuthi, ngenkathi kuguqulwa imvamisa, i-voltage ephumayo yesiguquli se-frequency kufanele ilawulwe ukuze kugcinwe ukugeleza kozibuthe okuthile kwenjini futhi kugwenywe ukwenzeka kozibuthe obuthaka kanye nezimo zikamagnetic saturation. Le ndlela yokulawula ijwayele ukusetshenziselwa iziguquli zefrikhwensi zokonga amandla kumafeni namaphampu.