Masu samar da na'urorin amsa makamashi don masu sauya mitar suna tunatar da ku cewa a cikin tsarin kula da mitar na al'ada wanda ya ƙunshi masu sauya mitar mitoci, injinan asynchronous, da lodin injina, lokacin da aka sauke yuwuwar nauyin da injin ke ɗauka, motar na iya kasancewa cikin yanayin birki mai sabuntawa; Ko kuma lokacin da motar ke raguwa daga babban gudu zuwa ƙananan gudu (ciki har da filin ajiye motoci), mitar na iya raguwa ba zato ba tsammani, amma saboda inertia na injin, yana iya kasancewa a cikin yanayin samar da wutar lantarki. Akwai hanyoyi guda biyu don ɗaukar makamashin sake haɓakawa na mai sauya mitar: ɗaya ita ce hanyar juriya ta fitar da makamashi; Wata hanyar ita ce hanyar mayar da martani. Hanyar mayar da martani ita ce tsarin "dual PWM" wanda ya ƙunshi cikakken sarrafa abubuwan canzawa, amma tsadarsa yana iyakance amfani da shi. A ƙasa akwai gabatarwa ga sabuwar hanyar mayar da martani don sabunta kuzari a cikin mai sauya mitar.
Ƙa'idar aiki na amsawar makamashi
Ra'ayin makamashi mai sabuntawa shine mayar da makamashin lantarki da aka tara a ƙarshen biyu na capacitor na tacewa wanda motar ta haifar a cikin yanayin sabunta birki zuwa grid wuta. A matsayin da'irar ra'ayi, ya kamata a cika sharuɗɗa biyu:
(1) Lokacin da mitar ke aiki akai-akai, na'urar amsa ba ta aiki. Na'urar amsawa tana aiki ne kawai lokacin da wutar lantarkin bas na DC ya fi ƙima. Lokacin da ƙarfin wutar lantarki na DC bas ya koma al'ada, na'urar amsa ya kamata a kashe a kan lokaci, in ba haka ba zai ƙara nauyi akan da'irar gyarawa.
(2) Ra'ayin halin yanzu na inverter ya kamata a iya sarrafawa.
Sashin inverter
V1-V6 thyristors suna samar da da'irar inverter gada mai hawa uku. Thyristors suna da fa'idodin ƙarancin farashi, sarrafawa mai sauƙi, ingantaccen aiki, da fasaha mai girma. Amma thyristors su ne Semi sarrafawa aka gyara, kuma inverter kewaye da thyristors dole ne tabbatar da cewa mafi m inverter kwana ya fi 30 °, in ba haka ba yana da sauki don haifar da gazawar inverter, amma wannan ya sa al'ada irin ƙarfin lantarki na DC bas ya fi ƙarfin inverter. Da'irar inverter da ta ƙunshi thyristors na iya fara inverter ta hanyar fitar da bugun bugun jini, amma ba zai iya dakatar da inverter ta soke bugun bugun. Idan an soke bugun bugun bugun jini yayin jujjuyawar, zai haifar da mummunan sakamako na gazawar juyarwa. Saboda haka, wajibi ne a yi amfani da hanyar da za a yanke da'irar DC don dakatar da inverter.
Ayyukan VT sau biyu ne: ɗaya shine sarrafa farawa ko tasha na da'irar inverter. Lokacin da aka kunna VT, ana amfani da wutar lantarki na DC akan gadar inverter don fara inverter; Lokacin da aka kashe VT, za a yanke da'irar DC kuma inverter yana tsayawa (a wannan lokacin, bugun bugun jini na zaɓi ne). Wutar lantarki ta al'ada ta bas ɗin DC tana kusan DC600V (la'akari da jujjuyawar ± 10% a cikin wutar lantarki). Tasha tasha na inverter ya dogara da girman ƙarfin lantarkin motar bas na DC kuma yana ɗaukar ikon sarrafa hysteresis. Lokacin da wutar lantarki na DC bas ya fi 1.2 × 600V, an fara inverter, kuma lokacin da yake ƙasa da 1.1 × 600V, ana kashe inverter. Wani aikin VT shine sarrafa girman inverter current.
Sarrafa inverter halin yanzu
Lokacin juyawa, wutar lantarki bas na DC da ƙarfin inverter suna haɗuwa a layi daya tare da polarity iri ɗaya, kuma ƙarfin motar bas ya fi ƙarfin inverter. Ana amfani da Inductance L don daidaita bambancin wutar lantarki. Ikon VT na iya ɗaukar hanyar sarrafa hysteresis na PWM na yanzu, kuma ana amfani da hanyar hysteresis na yanzu anan.
Lokacin da iL<I Α L-IL, VT ke gudanarwa; Ana amfani da wutar lantarki kai tsaye zuwa inductor L da gadar inverter, samar da halin yanzu a cikin hanya ①, kuma iL na yanzu ya fara tashi; Lokacin da iL ya tashi sama da I3 L+IL, VT yana kashe kuma inductor yana ci gaba da gudana ta diode D. IL na yanzu yana fara raguwa. Lokacin da iL ya sauke zuwa I3 L-IL, VT yana sake gudanarwa kuma iL ya fara tashi kuma. Ta hanyar kunnawa / kashe canje-canje na VT, iL inverter na yanzu ana kiyaye shi a ƙayyadaddun ƙimar I3, kuma ba tare da la'akari da yadda ƙimar ƙimar ƙarfin wutar lantarki ta canza ba, saboda amfani da babban juzu'i mai ƙarfi, inductance L na iya zama ƙanƙanta.
A taƙaice, gudanar da VT ya kamata ya dace da sharuɗɗa guda biyu lokaci guda: (1) ƙarfin lantarki na DC Uc ya fi ƙarfin ƙarfin da aka saita; (2) Lokacin da inverter halin yanzu iL ya kasa da saita ƙananan iyaka na halin yanzu.
Kashewar VT yakamata ya dace da ɗayan sharuɗɗan guda biyu masu zuwa: (1) ƙarfin lantarki na DC Uc ya yi ƙasa da ƙaƙƙarfan ƙayyadaddun ƙarfin lantarki; (2) Lokacin da inverter halin yanzu iL ya wuce kafa babba iyaka.
Don guje wa sauyawa VT akai-akai, ana amfani da sarrafa hysteresis don ƙarfin lantarki Uc da iL na yanzu, kuma faɗin madauki shine bambanci tsakanin saita babba da ƙananan iyaka.
Lissafi na inductance
Don sauƙaƙe ƙididdiga kuma watsi da sauye-sauyen nan take na wutar lantarki inverter Vd Β, wanda aka yi la'akari da yawa akai-akai, za'a iya samun ma'auni mai zuwa: L diL dt = Uc Ud Β Magance ƙididdiga ya haifar da t1 = 2ILL Uc Ud Β, inda IL - fadin hysteresis na yanzu;
Uc - DC ƙarfin lantarki; Ud Β - matsakaicin ƙimar wutar inverter.
A cikin t2 tazara, VT yana kashe kuma ƙarfin lantarki yana ci gaba da gudana ta hanyar D.
Akwai ma'auni mai zuwa: L diL dt = - Ud Β Magani: t2=2ILL Ud Β Yankakken lokaci: T=t1+t2=2ILLUc Ud Β (Uc Ud Β) Yanke mitar: f=Ud Β (Uc Ud Β) IILLUc inductance: LU=Ud Β (Uc Ud Β) Lissafin da ke sama yana nuna cewa lokacin f yana da girma, L yana da ƙanƙanta. Wannan ya bambanta da na yau da kullun na thyristor inverter. Za a iya amfani da dabarar da ke sama a matsayin tushen zaɓin inductance.
Ƙididdigar fitarwa na capacitor na yanzu
Sai kawai lokacin da VT ke gudanarwa, za'a iya samun fitarwa mai gudana daga cikin capacitor. Saboda haka, matsakaicin darajar fitarwa na halin yanzu shine: Ic=t1 TI 3 L. Sauya wannan dabarar a cikin tsarin zagayowar tsinke, sakamakon shine: Ic=Ud Β Uc I 3 L.