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mblowes asked

VFD to charge 3phase Multiplus

I've just completed a 3 phase installation using Multis. Everything worked well except how to power in event of a grid outage. We have a fairly reliable grid here in the Australian country but it does go out from time to time.


The setup runs on its own energy 95% of the time. So put these things together it wont be often that the grid is out and we dont have our own power.


The 3phase multis need 3 phase input to charge. 3 phase generators are significantly more expensive than 1 phase. But I just noticed that 5kW VFDs (1P to 3P) are quite cheap.


Can I use one of these? ie a VFD on the output of a genset?

Multiplus-IIoffgrid3 phase
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2 Answers
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svtti123 answered ·

the short answer

why not micro inverters convert dc to ac that the mutiplus has no problem with the only difference is the vfd is a variable frequency drive that you would set to match the hertz in your region.

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svtti123 avatar image svtti123 commented ·

I should add a vfd takes ac converts it to dc and then back to ac one more step tahn the micro inverter

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mblowes avatar image mblowes commented ·

how would you get the phases 120% offset with micro inverters? the Multi's in 3phase are looking for other input on each phased and for it to be in-inphase.

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svtti123 avatar image
svtti123 answered ·

i would run it by victron but syncing the the three inverters together should not be necessary since the incoming ac is at the correct phase angle to begin with each unit passing the ac as is. as long as each phase is a copy of incoming to outgoing .

i think its a great idea worth pursuing.

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