Ii-inverters ziyinxalenye yeqela elikhulu lee-static converters, eziquka uninzi lwanamhlanje.'izixhobo ezikwaziyo uku“guqula"iiparameter zombane ekungeneni, ezifana ne-voltage kunye ne-frequency, ukuze kuveliswe imveliso ehambelana neemfuno zomthwalo.

Ngokubanzi, ii-inverters zizixhobo ezikwaziyo ukuguqula i-direct current ibe yi-alternating current kwaye zixhaphake kakhulu kwizicelo ze-industrial automation kunye nee-electric drives. Uyilo kunye noyilo lweentlobo ezahlukeneyo ze-inverter luyatshintsha ngokwesicelo ngasinye esithile, nokuba undoqo wenjongo yazo ephambili ufana (ukuguqulwa kwe-DC ukuya kwi-AC).

1. Ii-Inverters ezizimeleyo neziqhagamshelwe kwiGrid

Ii-inverters ezisetyenziswa kwizicelo ze-photovoltaic ngokwembali zahlulwe zibe ziindidi ezimbini eziphambili:

:Ii-inverters ezizimeleyo

:Ii-inverters eziqhagamshelwe kwigridi

Ii-inverters ezizimeleyo zenzelwe usetyenziso apho isityalo se-PV singaqhagamshelwanga kwinethiwekhi ephambili yokusasazwa kwamandla. I-inverter iyakwazi ukubonelela ngamandla ombane kwimithwalo eqhagamshelweyo, iqinisekisa uzinzo lweeparamitha eziphambili zombane (i-voltage kunye ne-frequency). Oku kuzigcina ngaphakathi kwemida echazwe kwangaphambili, zikwazi ukumelana neemeko zokugqithisa okwethutyana. Kule meko, i-inverter idityaniswe nenkqubo yokugcina ibhetri ukuqinisekisa ukunikezelwa kwamandla okuqhubekayo.

Kwelinye icala, ii-inverters eziqhagamshelwe kwigridi ziyakwazi ukuvumelanisa negridi yombane eziqhagamshelwe kuyo kuba, kule meko, i-voltage kunye ne-frequency ziyasebenza.“ebekwe"Ezi inverters kufuneka zikwazi ukuqhawula umbane ukuba igridi ephambili ayisebenzi ukuze kuthintelwe naluphi na unikezelo olubuyela umva lwegridi ephambili, olunokuba yingozi enkulu.

Umfanekiso 1 - Umzekelo wenkqubo ezimeleyo kunye nenkqubo eqhagamshelwe kwigridi. Umfanekiso ngoncedo lukaBiblus.

2. Yintoni indima ye-Bus Capacitor

Injongo ye-inverter kukuguqula i-voltage ye-DC waveform ibe yisignali ye-AC ukuze kufakwe amandla kumthwalo (umz. igridi yamandla) kwi-frequency ethile kunye ne-engile encinci yesigaba (φ ≈0). Isekethe elula ye-single phase unipolar Pulse-Width Modulation (PWM) iboniswe kuMfanekiso2 (isicwangciso esifanayo sinokwandiswa ukuya kwinkqubo yezigaba ezintathu). Kule nkqubo, inkqubo ye-PV, esebenza njengomthombo we-DC voltage ene-inductance ethile yomthombo, ibunjwe ibe yisignali ye-AC ngokusebenzisa iiswitshi ezine ze-IGBT ngaxeshanye kunye nee-freewheeling diodes. Ezi switshi zilawulwa esangweni ngesignali ye-PWM, edla ngokuba yimveliso ye-IC ethelekisa igagasi lomthwali (ngesiqhelo yi-sine wave ye-output frequency efunekayo) kunye negagasi lesalathiso kwi-frequency ephezulu kakhulu (ngesiqhelo yi-triangle wave kwi-5-20kHz). Imveliso ye-IGBTs ibunjwe ibe yisignali ye-AC efanelekileyo ukusetyenziswa okanye i-grid injection ngokusebenzisa ii-topologies ezahlukeneyo zee-LC filters.

Fumana Ixabiso

Umfanekiso 2: Ukuguquguquka kobubanzi bePulsed (PWM) kwisigaba esinyeukuseta i-inverter. Iiswitshi ze-IGBT, kunye nesihluzi se-LC output, zibumba isignali yokufaka ye-DC ibe sisignali ye-AC esebenzisekayo. Oku kubangelai-voltage engalunganga ephazamisayo kwiiterminal ze-PV. Ibhasii-capacitor ilinganiswe ngobukhulu ukuze kuncitshiswe le ripple.

Ukusebenza kwe-IGBTs kungenisa i-ripple voltage kwi-terminal ye-PV array. Le ripple iyingozi ekusebenzeni kwenkqubo ye-PV, kuba i-nominal voltage esetyenziswa kwi-terminals kufuneka ibanjwe kwindawo yamandla aphezulu (MPP) ye-IV curve ukuze kukhutshwe amandla amaninzi. I-voltage ripple kwi-PV terminals iya kujika amandla akhutshwe kwinkqubo, nto leyo ebangela ukuba

amandla aphantsi aphumayo (Umfanekiso 3). I-capacitor yongezwa ebhasini ukuze igudise i-voltage ripple.

Umfanekiso 3: I-voltage ripple engeniswa kwiiterminal ze-PV yi-PWM inverter scheme itshintsha i-voltage esetyenzisiweyo kwi-max power point (MPP) ye-PV array. Oku kwazisa i-ripple kwi-power output ye-array ukuze amandla aphakathi e-output abe ngaphantsi kwe-nominal MPP.

I-amplitude (ukusuka kwincopho ukuya kwincopho) ye-voltage ripple imiselwa yi-switching frequency, i-PV voltage, i-bus capacitance, kunye ne-filter inductance ngokwe:

apho:

I-VPV yi-voltage ye-DC yephaneli yelanga,

I-Cbus yi-capacitance ye-capacitor yebhasi,

I-L yindlela yokungenisa izinto ezisetyenziswa kwi-filter inductors,

i-fPWM yindlela yokutshintsha rhoqo.

I-equation (1) isebenza kwi-capacitor efanelekileyo ethintela itshaja ukuba ingadluli kwi-capacitor ngexesha lokutshaja ize ikhuphe amandla akwintsimi yombane ngaphandle kokuxhathisa. Enyanisweni, akukho capacitor ifanelekileyo (Umfanekiso 4) kodwa yenziwe ngezinto ezininzi. Ukongeza kwi-capacitance efanelekileyo, i-dielectric ayixhathisi ngokupheleleyo kwaye umsinga omncinci wokuvuza uphuma kwi-anode uye kwi-cathode ngokulandelana kwe-finite shunt resistance (Rsh), udlula i-dielectric capacitance (C). Xa umsinga odlula kwi-capacitor uhamba, ii-pins, ii-foils, kunye ne-dielectric azihambi kakuhle kwaye kukho ukumelana nochungechunge olulinganayo (ESR) ngokulandelana kunye ne-capacitance. Okokugqibela, i-capacitor igcina amandla athile kwintsimi yemagnethi, ngoko ke kukho i-equivalent series inductance (ESL) ngokulandelana kunye ne-capacitance kunye ne-ESR.

Umfanekiso 4: Isekethe elinganayo ye-capacitor eqhelekileyo. I-capacitor yiyenziwe ngezinto ezininzi ezingezizo ezilungileyo, kuquka i-dielectric capacitance (C), i-non-infinite shunt resistance ngokusebenzisa i-dielectric edlula i-capacitor, i-series resistance (ESR), kunye ne-series inductance (ESL).

Kwanakwicandelo elibonakala lilula njenge-capacitor, kukho izinto ezininzi ezinokungaphumeleli okanye ziwohloke. Elinye lala macandelo linokuchaphazela indlela esebenza ngayo i-inverter, kumacala e-AC kunye ne-DC. Ukuze kuchongwe isiphumo sokuwohloka kwezixhobo ze-capacitor ezingezizo ezifanelekileyo kwi-voltage ripple ezifakwe kwiiterminal ze-PV, i-inverter ye-PWM unipolar H-bridge (Umfanekiso 2) yalinganiswa kusetyenziswa i-SPICE. Ii-capacitors zesihluzo kunye nee-inductors zibanjwe kwi-250µF kunye ne-20mH, ngokwahlukeneyo. Iimodeli ze-SPICE ze-IGBTs zithathwe kumsebenzi kaPetrie et al. Isignali ye-PWM, elawula ii-switches ze-IGBT, imiselwa yisekethe ye-comparator kunye ne-inverting comparator kwiiswitches ze-IGBT eziphezulu nezisezantsi, ngokwahlukeneyo. Igalelo labalawuli be-PWM yi-9.5V, 60Hz sine carrier wave kunye ne-10V, 10kHz triangular wave.