3 Phase AC coupled system with single phase Input on 4 th Inverter

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Adam asked Jun 16, '21

3 Phase AC coupled system with single phase Input on 4 th Inverter

Hi

Wondering if I can run AC coupled solar (on Victron output) on a 3 phase system with single phase grid input ?

I know this works with DC coupled, as I can just turn off switched as group and passthrough/ invert single phase supply to DC then back to 3 phase AC , however can not run PV inverter support or ESS when not switched as group ( so not control available via frequency shifting).

So my question is if I run a 4th quattro, can I add that to phase L1 and and use that to facilitate my single phase supply and have that invert AC supply to DC that way.

I have built the system in demo mode and it looks like it will allow it, but will it actually work? Also it is allowing me to run ESS in the config that I have built, will ESS work under this config as the client wants to export excess solar.

any help would be greatly appreciated.

Thanks

3 phase

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Modifications Space

Node Red Space

Answer 1 · 2021-06-19T09:50:47Z

Alexandra answered · Jun 19, 2021 at 09:50 AM

@Adam

Is this an offgrid system? If it is pv support would be better.

You would not need to AC connect the single to the three phase for charging if you have shunt based soc measuring.

Just use the 4th inverter as a charger from the other source. That way switching as a group is not an issue, but you are still able to charge the batteries.

https://community.victronenergy.com/questions/70448/3-phase-system-and-single-phase-mp.html

There have been a few concerns over batterys who self manage charge. So you can get creative https://community.victronenergy.com/questions/73505/3-phase-multiplus-ii-ess-system-with-an-additional.html

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Answer 2 · 2021-07-05T00:09:49Z

Adam answered · Jul 05, 2021 at 12:09 AM

Thanks for your help Alexandra,

We ended up using the 4th inverter as your have suggested, however I ended up running a separate GX device to control run the 4th inverter, basically so I could Run ESS on the grid Tie (4th) as the client wanted to have some control over how the grid interacted with the system and also a part of the system requirement was to be able to facilitate Grid export. We ended up controlling functions between the 2 GX devices using our Redflow BMS which has the functionality to push Modbus endpoints in the GX devices.

I noticed in the links you supplied some one else had done a similar set up using a GX device and a PI running Venus, using Node red to run functions between the two, this method would have also worked for me, but we got away with the BMS functionality this time, I will keep this in mind for next time.

It required a bit of tuning but so far is running really well.

thanks again

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