Grid-Forming vs. Grid-Following Inverters

A cikin off-grid power system, zabi na grid-forming inverter ko grid-following inverter ba ta fuskanci na wani matsayi ne na efficiency a cikin wani matsayi na percentage. Amma shine farko a tsarin da ke haifar da voltage ko tsari na ba za a iya farin da shi ba. Farko ya kasance a cikin wani hukuma na kontrol: current source ko voltage source.

Current Source vs. Voltage Source

Inverter mai tsayi a cikin gida ya yi amfani da kudin yanki na kuma amsa kuma ya ƙara kudin yanki a cikin gida. Ya amfani da phase-locked loop don gano fasal din yankin AC wanda ke ciki kuma ya ƙara kudin yanki a cikin gida ta hanyar fasal din yankin AC wanda aka saba. Ya dace da yankin AC da fasal din yankin AC wanda ke ciki don ayyana. A cikin gida wanda ba shi da yankin AC, inda ba a samu fasal din yankin AC, inverter mai tsayi a cikin gida ba shi da wani abu da ya tsaya a cikin gida.

Inverter mai tsayi a cikin gida, wanda ke cikin gida, ya yi amfani da yankin AC. Ya saba yankin AC ta hanyar fasal din yankin AC da yankin AC wanda ke cikin gida, kuma sauran abubuwan da suka tsaya a cikin gida suna tsaya a cikin gida ta hanyar fasal din yankin AC. A wannan matsayi, yana da alama na generator mai tsayi: ba ya jira don gida ya zama; ya saba alama na gida.

Wace sabon gida wanda ke cikin gida ke bukatar tsayin gida

A cikin microgrid ko system na islanded, ba wani grid na utility ya ba mu baseline na voltage da frequency. Idan system na power conversion (PCS) ya shiga a mode na grid-following, kuma ba wani device a cikin system yake neman amfani da responsibility na samun baseline din. Microgrid ba za ta iya shiga a cikin voltage ba. Wannan ba kamar yadda ya zama kuskure na performance; amma wannan shine condition na musu a matsayin function.

Wannan hukuma ta sama ta amfani ne idan motor loads na high-power suka daga. Induction motors suna ci inrush current mai yawa a lokacin start-up, kuma wannan current zai iya gudan yadda inverter control loops a cikin microgrid na islanded. Inverter na grid-forming dole ne ya ba madaidaici voltage drop na momentary a cikin IEEE Std. 1547 ride-through limits domin samun voltage regulation kuma kara gudan trip.

Inverters na grid-following ba su da wannan ƙwamfinta a cikin bayanai na off-grid, saboda suna ba abu ne na samun voltage a farko. A cikin microgrids, lokaci na islanded na industriya, da lokaci na kwalla ko karkara na gaba daya, ƙwamfinta na grid-forming shine abu da yawa da aka bukatar shi, ba abu na iya zartarwa ba.

Abin da ke ciki a gano a cikin PCS na grid-forming

Abubuwan da suka daga cikin ƙwamfinten da yawa su ne: black start (samun voltage daga halin da ba shi da energy), amsa na inertia a tsawon millisecond, taimakawa na short-circuit current don kuskure ta hanyar motor-starting transients, da kuma fuskantarwa mai kyau ne akan tsarin grid-connected zuwa tsarin islanded.

Misalai mai amfani shi ne kuma PCS na gida ta hanyar tashin transformer mai saukarwa, kamar wadanda Zhongmeng (Jiangsu Zhongmeng Electrical) suka ba da. A cikin yadda PCS na gida ta hanyar tashin yadda ya zama mafi kyawu, ya nuna waqtar amsa ta 10 ms ko ƙasa, kuma aiki mai tsaya a matsayin SCR (short-circuit ratio) ta ƙasa da 1.1, wanda abubuwan da suka fito daga gida na gida suna da alaƙa da kariya a cikin wannan fahimta.

Wannan yadda ya kuma yana da aiki na inertia, kontrolin damping, aiki na kwayoyin masu kara, black start, kuma taimaka ga jump na phase-angle, kuma efficiency na aiki ta 98.5% ko ƙasa. Wadannan bayanan suka fiye da kuma ba suka fiye da bayanan market, amma suka fiye da kuma suka hada da kuma dukkanin halin da aka bayani a baya.

Kura na Kura na Kura

A cikin yadda ake sabauni PCS don project na gida ta hanyar tashin, akwai hudu tambaya da suka fiye da kariya.

1. Yana da alaƙa da kariya da kariya na aiki na gida ta hanyar tashin? Idan haka, kontrolin gida ta hanyar tashin shine babban shirin da ke cikin kariya.

2. Shin PCS zai iya aiki da black start kuma zai iya samun voltage a cikin bus mai kariya?

3. Wani ne lokacin gaba daya na inertia, kuma akayi shi a millisecond ba a second ba?

4. Yana iya taka wani abu mai yawa a cikin inrush current na motor loads ba tare da fuskanci ba?

Idan wani daga wannan bayani ba ya fi fahimci, mode na control ba a saba amfani ba.

Mai amfani daidai

Wani inverter na grid-forming ba shi ne "maki" ga inverter na grid-following. Shishe ne wani nau'in abu da ke cikin wani nau'in baya, wanda ya dace da wani nau'in halin tashin kudada. A cikin sistemai na off-grid, za a zaba nau'in control da ke dace sosai don yin amfani da shi kuma ba a saba amfanin kudada ba.

Babban Tambayoyi

T: Wane ne farko mai sauwi a tsarin grid-forming da grid-following inverters?

L: Grid-forming ya yi amfani da voltage source wanda ya samu reference na sarrafa; grid-following ya yi amfani da current source wanda ya bukata voltage na gaba don ya follow.

T: Akwai inverter na grid-following zai iya aiki a cikin sistemai na off-grid?

L: Ba. Bayan kuma voltage reference na gaba, inverter na grid-following ba shi da signal don ya synchronize da shi kuma ba za a iya kurba ba.

T: Wane ne black start capability?

A: Iyaka in gudanar da bus mai karya kuma samun voltage ba tare da kowa yanzu na kayan gida.

Q: Me ya sa lokacin amsa ya dace don PCS na gaba'atarwa?

A: Lokacin amsa mai kyau (10 ms ko ƙasa) yana nuna kariya na voltage a lokacin canzawa mai tsoro na load ko lokacin shiga na motor a sistemai na gaba'atarwa.

Q: Me ya kunika SCR ta hanyar 1.1 don PCS?

A: Yana nuna cewa PCS zai iya karyata a wani hali na grid mai karya, inda SCR ya kasance babba. able operation in weak grid conditions where the short-circuit ratio is very low.