Abahlinzeki bemishini esekela i-frequency converter bakukhumbuza ukuthi ezinhlelweni zendabuko zokulawula imvamisa ezakhiwe iziguquli ezijwayelekile, ama-asynchronous motors, nemithwalo yemishini, lapho umthwalo ongaba khona odluliswa yinjini wehliswa, injini ingase ibe sesimweni sokubhuleka kabusha; Noma lapho injini yehla isuka ejubaneni elikhulu iye kwisivinini esiphansi (kuhlanganise nokupaka), imvamisa ingase yehle ngokuzumayo, kodwa ngenxa ye-inertia yomshini wenjini, ingase ibe sesimweni sokukhiqiza amandla kabusha. Amandla emishini agcinwe ohlelweni lokudlulisa aguqulwa abe amandla kagesi yinjini futhi abuyiselwe kusekethe ye-DC ye-inverter ngama-diode ayisithupha ahamba ngamasondo e-inverter. Ngalesi sikhathi, i-inverter isesimweni esilungisiwe. Kuleli qophelo, uma zingekho izinyathelo ezithathwayo ukuze kudle amandla kusiguquli sefrikhwensi, la mandla azobangela ukuba i-voltage ye-capacitor yokugcina amandla kusekethe emaphakathi ikhuphuke. Uma i-braking ishesha kakhulu noma umthwalo wemishini uyi-hoist, le ngxenye yamandla ingase ibangele umonakalo kusiguquli samafrikhwensi, ngakho-ke kufanele sicabangele le ngxenye yamandla.
Eziguqulini ezijwayelekile, kunezindlela ezimbili ezivame ukusetshenziswa kakhulu zokucubungula amandla avuselelwe:
(1) Ukuhlakazeka ku-"braking resistor" esethwe ngokuzenzisa ngokuhambisana ne-capacitor kusekethe ye-DC kubizwa ngokuthi yi-dynamic braking state;
(2) Uma ibuyiselwa kugridi yamandla, ibizwa nge-feedback braking state (eyaziwa nangokuthi isimo sokuvuselela ibhuleki). Kukhona enye indlela yokubhuleka, okuyi-DC braking, engasetshenziswa ezimeni lapho kudingeka khona ukupaka okunembile noma lapho i-brake motor ijikeleza ngokungavamile ngenxa yezinto zangaphandle ngaphambi kokuqala.
Ochwepheshe abaningi baxoxisane ngokuklama nokusetshenziswa kwe-variable frequency drive braking ezincwadini nasekushicilelweni, ikakhulukazi ezikhathini zamuva nje, kuye kwaba nezindatshana eziningi ezikhuluma "nge-energy feedback braking". Namuhla, umlobi wethula uhlobo olusha lwe-braking method, enezinzuzo zokusebenza ezine ezine-quadrant "ne-feedback braking" kanye nokusebenza kahle okuphezulu, kanye nezinzuzo "ze-energy ukusetshenziswa kwe-braking" yegridi yamandla engenawo ukungcola kanye nokuthembeka okuphezulu.
Ukubhuleka ukusetshenziswa kwamandla
Indlela yokusebenzisa i-resistor yokubhuleka esethwe kusekethe ye-DC ukuze imunce amandla kagesi avuselelwayo enjini ibizwa ngokuthi i-energy ukusetshenziswa braking.
Inzuzo yayo ukwakhiwa okulula; Akukho ukungcola kugridi yamandla (uma kuqhathaniswa nokulawula impendulo), izindleko eziphansi; Okubi wukusebenza kahle okuphansi, ikakhulukazi ngesikhathi sokubhuleka njalo, okuzodla inani elikhulu lamandla futhi kwandise umthamo we-resistor yokubhuleka.
Ngokuvamile, eziguqulini ezivamile, iziguquli zefrikhwensi yamandla aphansi (ngaphansi kuka-22kW) zifakwe iyunithi yebhuleki eyakhelwe ngaphakathi, edinga kuphela i-resistor yamabhuleki yangaphandle. Iziguquli zamandla aphezulu (ngaphezulu kuka-22kW) zidinga amayunithi amabhuleki angaphandle kanye nezinsimbi zamabhuleki.
Ukubhuleka kwempendulo
Ukuze uzuze ukubhuleka kwempendulo yamandla, izimo ezifana nokulawula i-voltage ngefrikhwensi efanayo nesigaba, ukulawulwa kwamanje kwempendulo, njll. kuyadingeka. Isebenzisa ubuchwepheshe be-inverter obusebenzayo ukuze iguqule amandla kagesi avuselelwe kumandla we-AC wefrikhwensi efanayo nesigaba njengegridi yamandla bese iwabuyisela kugridi, ngaleyo ndlela kuzuzwe ukubhuleka.
Inzuzo ye-feedback braking ukuthi ingasebenza ngama-quadrants amane, futhi impendulo yamandla kagesi ithuthukisa ukusebenza kahle kwesistimu. Ububi bayo yilezi:
(1) Le ndlela yokubhuleka impendulo ingasetshenziswa kuphela ngaphansi kukagesi wegridi ozinzile ongajwayele ukuba namaphutha (nokushintshashintsha kwegridi kagesi okungeqile ku-10%). Ngoba ngesikhathi sokusebenza kwe-braking yokukhiqiza amandla, uma isikhathi sephutha le-voltage yegridi yamandla sikhulu kuno-2ms, ukwehluleka kokushintsha kungase kwenzeke futhi izingxenye zingalimala.
(2) Phakathi nempendulo, kukhona ukungcoliswa kwe-harmonic kugridi yamandla.
(3) Ukulawula kuyinkimbinkimbi futhi izindleko ziphezulu.
Indlela entsha yokubhuleka (i-capacitor impendulo braking)
Isimiso sokujikeleza esiyinhloko
Ingxenye yokulungiswa isebenzisa ibhuloho elivamile lokulungisa elingalawuleki ukuze lilungiswe, isifunda sokuhlunga sisebenzisa i-universal electrolytic capacitor, futhi isifunda sokulibaziseka sisebenzisa i-contactor noma i-thyristor. Isifunda sokushaja nesempendulo siqukethe imojula yamandla ye-IGBT, i-reactor yokushaja nempendulo engu-L, kanye ne-electrolytic capacitor C enkulu (enomthamo wezingxenye eziyishumi ezimbalwa zemitha, enganqunywa ngokuya ngesistimu yokusebenza yesiguquli semvamisa). Ingxenye ye-inverter yakhiwe imojula yamandla ye-IGBT. Isekhethi yokuvikela yakhiwe i-IGBT kanye nokumelana namandla.
1) Isimo sokusebenza kokukhiqiza amandla kagesi
I-CPU iqapha okokufaka kukagesi we-AC kanye ne-DC yesekethe kagesi (μ d) ngesikhathi sangempela, futhi inquma ukuthi ithumele yini isignali yokushaja ku-VT1. Uma u-μ d isingaphezu kwevelu ye-voltage ye-DC ehambisanayo (efana no-380VAC -530VDC) we-voltage ye-AC yokufaka, i-CPU ivala i-VT3 futhi ishaje i-electrolytic capacitor C ngokusebenzisa i-pulse conduction ye-VT1. Ngalesi sikhathi, i-reactor L kanye ne-electrolytic capacitor C zihlukaniswa ukuze kuqinisekiswe ukuthi i-electrolytic capacitor C isebenza ngaphakathi kwebanga eliphephile. Uma i-voltage ku-electrolytic capacitor C isondela kunani eliyingozi (elifana no-370V) ngenkathi isistimu yisesimeni sokukhiqiza amandla, futhi amandla kagesi ethunyelwa ngokuqhubekayo emuva kusekethe ye-DC ngesiguquli, isekethe yokuphepha idlala indima ekuzuzeni ukusetshenziswa kwamandla amabhuleki (i-resistance braking), ukulawula ukucisha nokuvula i-VT3, futhi ngaleyo ndlela ukuqaphela ukusetshenziswa kwamandla ngokweqile akwenzeki ngokuqaphela lesi simo.
(2) Isimo sokusebenza kwemoto kagesi
Uma i-CPU ithola ukuthi isistimu ayisashaji, ishayela ishayela i-VT3, idale i-voltage engalungile yesokunxele eqondile kanye nenegethivu esheshayo ku-reactor L. Kuhlanganiswe ne-voltage ku-electrolytic capacitor C, inqubo yempendulo yamandla esuka ku-capacitor kuya kusekethi ye-DC ingafinyelelwa. I-CPU ilawula imvamisa yokushintsha nomsebenzi we-VT3 ngokuthola i-voltage ku-electrolytic capacitor C kanye ne-voltage kusekethe ye-DC, ngaleyo ndlela ilawule impendulo yamanje futhi iqinisekise ukuthi i-DC circuit voltage ν d ayibi kakhulu.
Izinkinga zesistimu
(1) Ukukhethwa kwama-reactor
(a)), Sicabangela ubunjalo bezimo zokusebenza futhi sicabange ukuthi iphutha elithile lenzeka ohlelweni, okubangela amandla amandla athwala amandla enjini ukuthi asheshise ngokukhululeka futhi awe. Ngalesi sikhathi, injini isesimweni sokusebenza kokukhiqiza amandla,
Amandla avuselelwe athunyelwa emuva kumjikelezo we-DC ngokusebenzisa ama-diode ayisithupha ahamba ngamasondo, okubangela ukwanda ku-∆ d nokubeka ngokushesha i-inverter esimweni sokushaja. Ngalesi sikhathi, umsinga uzoba phezulu kakhulu. Ngakho-ke i-diameter ye-reactor ekhethiwe kufanele ibe nkulu ngokwanele ukudlula okwamanje ngalesi sikhathi.
(b)), Kuluphu yempendulo, ukuze kukhululwe amandla kagesi amaningi ngangokunokwenzeka ngaphambi kokushajwa okulandelayo kwe-electrolytic capacitor, ukukhetha insimbi evamile (i-silicon steel sheet) akukwazi ukufeza umgomo. Kungcono ukukhetha i-iron core eyenziwe ngezinto ze-ferrite. Uma ubheka inani lamanje elicatshangelwe ngenhla, kungabonakala ukuthi lo mgogodla wensimbi mkhulu kangakanani. Akwaziwa ukuthi ukhona yini umnyombo wensimbi omkhulu kangaka we-ferrite emakethe. Ngisho noma ikhona, intengo yayo ngeke neze ibe phansi kakhulu.
Ngakho-ke umbhali uphakamisa ukusebenzisa i-reactor eyodwa kumjikelezo ngamunye wokushaja kanye nempendulo.
(2) Ubunzima bokulawula
(a)), Kumjikelezo we-DC we-frequency converter, i-voltage ν d ngokuvamile iphakeme kuno-500VDC, kuyilapho amandla okumelana ne-electrolytic capacitor C ingu-400VDC kuphela, okubonisa ukuthi ukulawulwa kwale nqubo yokushaja akufani nendlela yokulawula yokubhuleka kwamandla (i-resistance braking). Ukwehla kwamandla kagesi asheshayo okukhiqizwa ku-reactor kungukuthi, kanye ne-voltage yokushaja esheshayo ye-electrolytic capacitor C ingu-ν c=ν d - ν L. Ukuze kuqinisekiswe ukuthi i-electrolytic capacitor isebenza ngaphakathi kwebanga eliphephile (≤ 400V), kuyadingeka ukulawula ngempumelelo ukwehla kwamandla kagesi ν L ku-reactor, okuthi ngokuhamba kwesikhathi kuncike ekushintsheni kwamanje.
(b) 、 Phakathi nenqubo yempendulo, kuyadingeka futhi ukuvimbela ukukhishwa kwamandla kagesi ku-electrolytic capacitor C ekubangeleni i-voltage yesekethe ye-DC ngokweqile nge-reactor, okuholela ekuvikelweni kokugcwala ngokweqile ohlelweni.
Izimo zohlelo lokusebenza eziyinhloko
Kungenxa yayo kanye ukuthi ukuphakama kwale ndlela entsha yokubhuleka (i-capacitor feedback braking) yeziguquli zefrikhwensi abasebenzisi abaningi abasanda kuhlongoza ukuhlomisa ngayo le sistimu ngokusekelwe ezicini zemishini yabo. Ngokunwetshwa kwenkambu yohlelo lokusebenza yeziguquli zemvamisa, lobu buchwepheshe bohlelo lokusebenza buzoba nethemba elikhulu lokuthuthuka. Ikakhulukazi, isetshenziswa kakhulu ezimbonini ezinjengama-hoist asemayini (yokuthwala abantu noma ukulayisha impahla), izimoto zemayini ezithambekele (ishubhu elilodwa noma eliphindwe kabili), kanye nemishini yokuphakamisa. Kunoma yikuphi, amadivaysi empendulo yamandla angasetshenziswa ezimeni eziwadingayo.