Wind turbine inverter as AC In to the Multiplus?

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dyju711 asked Mar 23, '20

Wind turbine inverter as AC In to the Multiplus?

Hi Guys, I'm planning my off-grid system and I need some help with the design.

My initial plan is to use Mulitplus II GX/MultiGrid with DC coupled PV connected to the BYD battery pack. The issue at this stage is the optimal connection of the wind turbine (3 phase generator).

Inverter recommended for this turbine can operate in both on-grid and off-grid installations. In on-grid mode it would be connected to AC out of the Mulitplus. If I'm not wrong surplus energy can be used to charge the battery but without any control of the Victron or BYD BMU.

Off-grid model can be connected to the batteries and work without the grid but the communication with BMU/BMS isn't supported.

Do you think that it's possible to use output of the wind inverter as an input to the Multiplus (or as genset for MultiGrid)?

This is a schematic for the off-grid, 'connection point to the electricity grid' will be the Multi.

Both Multi and PS100 will be connected to the same battery pack, but charging/discharging will be disabled in PS100. This should allow Multi to use power generated from wind to charge the batteries in line with BMU communication. If I'm not wrong it will also resolve the problem with overcharging the batteries.

What's your thoughts about this approach?

Hydro and Wind Power

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Answer 1 · 2020-03-23T10:42:22Z

Daniël Boekel (Victron Energy Staff) answered · Mar 23, 2020 at 10:42 AM

Hi @Dyju711

You'll have to treat the wind inverter the same as a PV inverter, so connect it to the output (or if you'd have a grid connection you could use it on the input also)

Please check if the inverter supports frequency shift control and take the 1:1 rule seriously.

https://www.victronenergy.com/live/ac_coupling:start

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dyju711 commented · Mar 23, 2020 at 03:04 PM

Thanks @Daniël Boekel (Victron Energy Staff) for your response.

Unfortunately the wind inverter does not support frequency shift. It requires connection to dump load resistors but I'm not sure if this will be enough to not overcharge the batteries.

Based on PS100 manual it seems like it can create 230V 50Hz output after connecting to the batteries. I was hopping that Multi/MultiGrid will be able to accept it as a "normal" grid and operate in ESS mode. Wouldn't it work that way?

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Daniël Boekel (Victron Energy Staff) ♦♦ dyju711 commented · Mar 23, 2020 at 10:05 PM

Hi @Dyju711

after reading a bit of the manual:

https://www.twerd.pl/images/pdf/ps100-user-manual-en.pdf

it seems that if you have the version with a battery, it can create a local grid. please note: this device needs a 96 volt battery, and that battery is -not- isolated from the 230 VAC the unit puts out.

I would not use the device with a battery, but as an 'on grid' installation. It -has- to support frequency shifting, otherwise it cannot work.

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dyju711 Daniël Boekel (Victron Energy Staff) ♦♦ commented · Mar 24, 2020 at 10:35 PM

Thanks Daniël, it's very kind of you.

I was almost sure that it can also work on 48V battery but I may be wrong.

I'll keep looking for another solution but it's hard to find a wind inverter :/

Could you explain what would be the impact of not isolated battery pack from the 230V output?

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Daniël Boekel (Victron Energy Staff) ♦♦ dyju711 commented · Mar 24, 2020 at 10:41 PM

Hi @Dyju711

Please try to get a local electrician involved for these questions, local regulations can differ.

But generally an unisolated system is a bad idea except if you know exactly what you are doing.

Just use a 'grid connected' version that supports frequency shifting and your in the game.

But also please make sure a wind generator is the right solution for you, you need a very 'clean' wind supply (so no trees nearby, a high tower, etc) and most people end up very disappointed with 'small' wind generators (generally anything under 3-4 meter diameter)

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dyju711 Daniël Boekel (Victron Energy Staff) ♦♦ commented · Mar 24, 2020 at 11:25 PM

I'll definitely ask electrician for help with the installation.

I'm not sure yet if the wind turbine will be necessary. I hope that PV will deliver enought energy even during the winter.

Thanks for your help ;)

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Matthias Fuchs dyju711 commented · May 15, 2023 at 04:51 PM

I was hoping too, that my PV (4,4 kWp) would deliver at least some electricity. But this winter we had 6 weeks where I had 0 output for most of the time, at beast 100w.

The wind is blowing all the time though.
So I'm too looking into wind generators right now too.

I'm not sure though if it is feasible. The off-the-shelf generators cost a big chunk of money, like the istabreeze 1500.

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sean Matthias Fuchs commented · May 17, 2023 at 07:49 AM

Please do some research into the reliability and durability of that WT before you purchase it.

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Juha Tuomala Daniël Boekel (Victron Energy Staff) ♦♦ commented · Mar 03 at 01:57 PM

Those inverters have Modbus interfaces, does VenusOS support that? I mean the protocol Twerd uses. I understand that it could be used instead of frequency shifting. @Daniël Boekel (Victron Energy Staff)

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