Lub hom phiaj ntawm lub inverter yog hloov lub zog DC waveform mus rau hauv lub teeb liab AC kom txhaj lub zog rau hauv lub nra hnyav (piv txwv li lub zog fais fab) ntawm qhov zaus muab thiab nrog lub kaum sab xis me me (φ ≈0). Ib lub voj voog yooj yim rau ib theem unipolar Pulse-Width Modulation (PWM) tau qhia nyob rau hauv Daim Duab2 (cov qauv dav dav tib yam tuaj yeem nthuav dav mus rau peb theem system). Hauv daim duab qhia no, lub PV system, ua haujlwm ua DC voltage qhov chaw nrog qee qhov inductance qhov chaw, yog tsim los ua AC teeb liab los ntawm plaub IGBT switches ua ke nrog freewheeling diodes. Cov switches no raug tswj hwm ntawm lub rooj vag los ntawm PWM teeb liab, uas feem ntau yog qhov tso zis ntawm IC uas piv rau lub carrier wave (feem ntau yog sine wave ntawm qhov zaus tso zis xav tau) thiab lub reference wave ntawm qhov zaus siab dua (feem ntau yog triangle wave ntawm 5-20kHz). Cov zis ntawm IGBTs yog tsim los ua AC teeb liab uas tsim nyog rau kev siv lossis grid txhaj tshuaj los ntawm kev siv ntau yam topologies ntawm LC lim dej.
Cov inverters koom nrog ib pawg loj ntawm cov static converters, uas suav nrog ntau ntawm niaj hnub no's cov khoom siv uas muaj peev xwm ua tau"hloov dua siab tshiab"cov kev teeb tsa hluav taws xob hauv cov tswv yim, xws li voltage thiab zaus, yog li ntawd los tsim cov zis uas sib xws nrog cov kev xav tau ntawm lub nra.
Feem ntau hais lus, cov inverters yog cov khoom siv uas muaj peev xwm hloov cov hluav taws xob ncaj qha mus rau hauv cov hluav taws xob hloov pauv thiab feem ntau pom muaj nyob rau hauv kev siv tshuab hauv kev lag luam thiab cov tsav hluav taws xob. Cov qauv thiab kev tsim ntawm ntau hom inverter hloov pauv raws li txhua daim ntawv thov tshwj xeeb, txawm tias lub hauv paus ntawm lawv lub hom phiaj tseem ceeb yog tib yam (DC rau AC hloov pauv).
1. Cov Inverters Txuas Nrog thiab Cov Grid
Cov inverters siv rau hauv cov ntawv thov photovoltaic keeb kwm muab faib ua ob pawg tseem ceeb:
:Cov inverters uas sawv ntawm lawv tus kheej
:Cov inverters txuas nrog grid
Cov inverters uas sawv ntawm nws tus kheej yog rau cov ntawv thov uas lub Hoobkas PV tsis txuas nrog lub network faib hluav taws xob tseem ceeb. Lub inverter muaj peev xwm muab hluav taws xob rau cov khoom thauj uas txuas nrog, ua kom ntseeg tau tias cov kev teeb tsa hluav taws xob tseem ceeb (voltage thiab zaus). Qhov no ua rau lawv nyob hauv cov kev txwv uas tau teev tseg ua ntej, tuaj yeem tiv taus cov xwm txheej overloading ib ntus. Hauv qhov xwm txheej no, lub inverter tau txuas nrog lub kaw lus khaws cia roj teeb kom ntseeg tau tias muaj kev muab hluav taws xob tas li.
Cov inverters txuas nrog lub grid, ntawm qhov tod tes, muaj peev xwm sib dhos nrog lub grid hluav taws xob uas lawv txuas nrog vim tias, hauv qhov no, voltage thiab zaus yog"raug yuam"los ntawm lub grid tseem ceeb. Cov inverters no yuav tsum muaj peev xwm txiav tawm yog tias lub grid tseem ceeb tsis ua haujlwm kom tsis txhob muaj kev xa hluav taws xob rov qab ntawm lub grid tseem ceeb, uas tuaj yeem sawv cev rau qhov txaus ntshai loj.
- Daim Duab 1 - Piv txwv ntawm Standalone system thiab Grid-connected system. Duab los ntawm Biblus.
2. Lub Luag Haujlwm ntawm Lub Capacitor Npav yog dab tsi?
Daim Duab 2: Pulsed Width Modulation (PWM) ib theemteeb tsa inverter. Cov IGBT switches, nrog rau LC output filter, ua rau DC input signal mus rau hauv ib qho usable AC signal. Qhov no ua rau muajcov hluav taws xob tsis zoo hla cov PV terminals. Lub tsheb npavLub capacitor yog sized kom txo qhov ripple no.
Kev ua haujlwm ntawm IGBTs ua rau muaj lub zog hluav taws xob ripple rau ntawm lub davhlau ya nyob twg ntawm PV array. Qhov ripple no ua rau lub luag haujlwm ntawm PV system tsis zoo, vim tias lub zog nominal siv rau cov davhlau ya nyob twg yuav tsum tuav ntawm qhov chaw siab tshaj plaws (MPP) ntawm IV nkhaus kom tau txais lub zog ntau tshaj plaws. Lub zog hluav taws xob ripple ntawm PV terminals yuav oscillate lub zog rho tawm ntawm lub system, ua rau
qhov tso zis hluav taws xob nruab nrab qis dua (Daim Duab 3). Ib lub capacitor raug ntxiv rau ntawm lub tsheb npav kom ua kom lub zog hluav taws xob du.
Daim Duab 3: Lub zog hluav taws xob uas tau tsim rau ntawm cov PV terminals los ntawm PWM inverter scheme hloov lub zog hluav taws xob siv tawm ntawm qhov chaw muaj zog siab tshaj plaws (MPP) ntawm PV array. Qhov no ua rau muaj lub zog hluav taws xob hauv cov zis hluav taws xob ntawm array kom lub zog tso zis nruab nrab qis dua li MPP nominal.
Qhov amplitude (peak to peak) ntawm qhov voltage ripple yog txiav txim siab los ntawm switching frequency, PV voltage, bus capacitance, thiab filter inductance raws li:
qhov twg:
VPV yog lub zog hluav taws xob DC ntawm lub hnub ci vaj huam sib luag,
Cbus yog lub peev xwm ntawm lub tsheb npav capacitor,
L yog qhov inductance ntawm cov lim inductors,
fPWM yog qhov zaus hloov pauv.
Kab zauv (1) siv rau lub capacitor zoo tagnrho uas tiv thaiv kom tsis txhob muaj hluav taws xob ntws los ntawm lub capacitor thaum lub sijhawm them thiab tom qab ntawd tso tawm lub zog nyob hauv lub tshav pob hluav taws xob tsis muaj kev tiv thaiv. Qhov tseeb, tsis muaj capacitor zoo tagnrho (Daim Duab 4) tab sis nws muaj ntau yam khoom. Ntxiv nrog rau lub peev xwm zoo tagnrho, lub dielectric tsis zoo tag nrho resistive thiab me me leakage tam sim no ntws los ntawm anode mus rau cathode raws li qhov tsis kam shunt finite (Rsh), hla lub dielectric capacitance (C). Thaum tam sim no ntws los ntawm lub capacitor, cov pins, foils, thiab dielectric tsis zoo tag nrho conducting thiab muaj qhov sib npaug series resistance (ESR) hauv series nrog lub capacitance. Thaum kawg, lub capacitor khaws qee lub zog hauv lub tshav pob magnetic, yog li muaj qhov sib npaug series inductance (ESL) hauv series nrog lub capacitance thiab ESR.
Daim Duab 4: Lub voj voog sib npaug ntawm lub capacitor dav dav. Lub capacitor yogmuaj ntau yam tsis zoo tagnrho, suav nrog dielectric capacitance (C), tsis muaj qhov tsis kawg shunt tsis kam los ntawm dielectric uas hla lub capacitor, series tsis kam (ESR), thiab series inductance (ESL).
Txawm tias nyob rau hauv ib qho khoom uas zoo li yooj yim li lub capacitor, muaj ntau yam khoom uas tuaj yeem ua tsis tiav lossis puas tsuaj. Txhua yam ntawm cov khoom no tuaj yeem cuam tshuam rau tus cwj pwm ntawm lub inverter, ob qho tib si ntawm AC thiab DC sab. Txhawm rau txiav txim siab qhov cuam tshuam ntawm kev puas tsuaj ntawm cov khoom capacitor tsis zoo tagnrho rau ntawm qhov voltage ripple uas tau qhia thoob plaws PV terminals, PWM unipolar H-bridge inverter (Daim Duab 2) tau simulated siv SPICE. Cov lim capacitors thiab inductors tau tuav ntawm 250µF thiab 20mH, raws li. Cov qauv SPICE rau IGBTs yog los ntawm kev ua haujlwm ntawm Petrie et al. Lub teeb liab PWM, uas tswj cov IGBT switches, yog txiav txim siab los ntawm lub comparator thiab inverting comparator circuit rau sab siab thiab qis IGBT switches, raws li. Lub tswv yim rau PWM tswj yog 9.5V, 60Hz sine carrier nthwv dej thiab 10V, 10kHz triangular nthwv dej.
- Kev daws teeb meem CRE
CRE yog ib lub tuam txhab ua lag luam siab heev uas tshwj xeeb hauv kev tsim cov capacitors zaj duab xis, tsom mus rau kev siv hluav taws xob electrionics.
CRE muab cov kev daws teeb meem ntawm cov yeeb yaj kiab capacitor series rau PV inverter uas suav nrog DC-link, AC-filter thiab snubber.
Lub sijhawm tshaj tawm: Lub Kaum Ob Hlis-01-2023