MaInverter ari muboka guru rema "static converters", ayo anosanganisira akawanda emazuva ano.'zvishandiso zvinokwanisa"shandura""maparamita emagetsi ari muzvinhu zvinopinda, akadai sevoltage uye frequency, kuitira kuti pave ne output inoenderana nezvinodiwa nemutoro.

Kazhinji, ma inverter ndiwo midziyo inokwanisa kushandura direct current kuita alternating current uye akajairika muma industrial automation applications uye electric drives. Magadzirirwo uye magadzirirwo emhando dzakasiyana dze inverter zvinoshanduka zvichienderana nekushandiswa kwega kwega, kunyangwe kana chinangwa chikuru chazvo chakafanana (DC to AC conversion).

1. MaInverter akazvimirira uye akabatana neGrid

MaInverters anoshandiswa mukushandiswa kwe photovoltaic akakamurwa muzvikamu zviviri zvikuru munhoroondo:

:Ma inverter akazvimirira

:Ma inverters akabatana negrid

Ma inverter akazvimirira ndeekushandisa kana fekitari yePV isina kubatana ne network huru yekugovera simba. Iyo inverter inokwanisa kupa simba remagetsi kune mitoro yakabatana, zvichiita kuti parameter huru yemagetsi (voltage uye frequency) igare yakasimba. Izvi zvinovachengetedza mukati memiganhu yakatarwa, zvichikwanisa kutsungirira mamiriro ekuremerwa kwenguva pfupi. Mumamiriro ezvinhu aya, iyo inverter inosanganiswa nehurongwa hwekuchengetera bhatiri kuitira kuti ive nechokwadi chekuti simba rinogara riripo.

Kune rumwe rutivi, ma inverter akabatana negrid anokwanisa kuenderana negrid yemagetsi yaakabatana nayo nekuti, muchiitiko ichi, voltage uye frequency zviri"zvakaiswa""negridi huru. Ma inverter aya anofanira kukwanisa kudzima kana gridi huru ikakundikana kuitira kudzivirira chero mukana wekudzosera gridi huru kumashure, izvo zvinogona kukonzera njodzi huru.

Mufananidzo 1 - Muenzaniso weSisitimu yakazvimirira uye sisitimu yakabatana neGrid. Mufananidzo kubva kuna Biblus.

2. Basa reBus Capacitor nderei?

Chinangwa che inverter ndechekushandura DC waveform voltage kuita AC signal kuitira kuti simba ripinzwe mumutoro (semuenzaniso power grid) pa frequency yakatarwa uye ne small phase angle (φ ≈0). Dunhu rakarerutswa reModulation yePulse-Width Modulation (PWM) yechikamu chimwe chete rinoratidzwa muMufananidzo.2 (chirongwa chimwe chete ichi chinogona kuwedzerwa kune system yezvikamu zvitatu). Muchirongwa ichi, sisitimu yePV, inoshanda se DC voltage source ine imwe source inductance, inoumbwa kuita AC signal kuburikidza ne IGBT switches ina dzakafanana ne freewheeling diodes. Maswitch aya anodzorwa pagedhi kuburikidza ne PWM signal, iyo inowanzo kuve kubuda kwe IC inoenzanisa carrier wave (kazhinji sine wave ye frequency inodiwa) uye reference wave pa frequency yakakwira zvakanyanya (kazhinji triangle wave pa 5-20kHz). Kubuda kwe IGBTs kunoumbwa kuita AC signal yakakodzera kushandiswa kana grid injection kuburikidza nekushandisa topology dzakasiyana dze LC filters.

Tora Mutengo

Mufananidzo 2: Pulsed Width Modulation (PWM) imwe-phaseKugadzika kweinverter. Maswichi eIGBT, pamwe chete neLC output filter, anoumba DC input signal kuita AC signal inoshanda. Izvi zvinokurudzirakukanganiswa kwemagetsi emagetsi pazviteshi zvePV. Bhazicapacitor yakakura kuitira kuderedza kuvhunduka uku.

Kushanda kweIGBTs kunounza ripple voltage pa terminal yePV array. Ripple iyi inokuvadza kushanda kwePV system, sezvo nominal voltage inoshandiswa kuma terminals inofanira kubatwa pa max power point (MPP) ye IV curve kuti ibudise simba rakawanda. Ripple voltage pa PV terminals ichazunguza simba rinotorwa kubva musystem, zvichikonzera

simba rinobuda zvishoma (Mufananidzo 3). Capacitor inowedzerwa mubhazi kuitira kuti ripple yemagetsi iite seyakapfava.

Mufananidzo 3: Kuputika kwemagetsi kunoiswa pama PV terminals nePWM inverter scheme kunobvisa voltage inoshandiswa kubva pa max power point (MPP) yePV array. Izvi zvinounza kubhururuka kwesimba rinobuda mu array kuitira kuti avhareji yesimba rinobuda rive rakaderera pane nominal MPP.

Amplitude (peak to peak) ye voltage ripple inotsanangurwa ne switching frequency, PV voltage, bus capacitance, uye filter inductance zvichienderana ne:

kupi:

VPV ndiyo voltage yeDC ye solar panel,

Cbus ndiyo capacitance yebhazi capacitor,

L ndiyo inductance yema filter inductors,

fPWM ndiyo frequency yekuchinja.

Equation (1) inoshanda kune capacitor yakakodzera inodzivirira chaji kuti isayerere nepa capacitor panguva yekuchaja uye yozoburitsa simba riri mumunda wemagetsi pasina resistance. Muchokwadi, hapana capacitor yakakodzera (Mufananidzo 4) asi inoumbwa nezvinhu zvakawanda. Kuwedzera kune capacitance yakakodzera, dielectric haina resistance yakakwana uye leakage current diki inoyerera kubva kuanode kuenda ku cathode ichitevedza finite shunt resistance (Rsh), ichipfuura dielectric capacitance (C). Kana current ichipinda nepa capacitor ichiyerera, mapini, mafoil, uye dielectric hazvisi kuita zvakanaka uye pane equivalent series resistance (ESR) mu sequence ne capacitance. Pakupedzisira, capacitor inochengeta simba mumunda wemagnetic, saka pane equivalent series inductance (ESL) mu sequence ne capacitance ne ESR.

Mufananidzo 4: Dunhu rakaenzana re capacitor. Capacitor ndiyoinoumbwa nezvinhu zvakawanda zvisina kunaka, zvinosanganisira dielectric capacitance (C), shunt resistance isingapere kuburikidza ne dielectric iyo inodarika capacitor, series resistance (ESR), uye series inductance (ESL).

Kunyangwe muchikamu chinoita sechiri nyore se capacitor, kune zvinhu zvakawanda zvinogona kutadza kana kuora. Chimwe nechimwe chezvinhu izvi chinogona kukanganisa maitiro e inverter, kumativi ese e AC ne DC. Kuti tione kuti kudzikira kwezvikamu zve capacitor zvisina kunaka kune sei pa voltage ripple yakaunzwa pa PV terminals, PWM unipolar H-bridge inverter (Mufananidzo 2) yakaedzwa uchishandisa SPICE. Ma filter capacitors nema inductors anochengetwa pa 250µF ne 20mH, zvichiteerana. Ma SPICE models ema IGBTs anobva mubasa raPetrie et al. Chiratidzo chePWM, chinotonga ma IGBT switches, chinosarudzwa ne comparator ne inverting comparator circuit yema high ne low-side IGBT switches, zvichiteerana. Zvinopinda zve PWM controls i 9.5V, 60Hz sine carrier wave uye 10V, 10kHz triangular wave.