2 Quattro working in parallel

DIY
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1

Hello everyone,

We are currently running some tests with two Quattro units that we want to operate in parallel before installing them onboard.

One of the tests we carried out raised the following question:
We noticed that when we connect the AC outputs of both Quattros together and then disconnect the AC input breakers of the Master or the Slave, the system keeps running without changing state.

For example, if both Quattros are charging the batteries and one of them loses its AC input, the system continues running as if nothing happened — it does not switch to “inverting.” More surprisingly, the Quattro without AC input keeps charging the batteries, because it receives power from the output of the Quattro that still has an active AC input.

I would like to know:

  1. Is this behavior normal?

  2. Is it expected that the Quattro without AC input produces a strange electrical noise in this situation?

Thanks in advance for your help!

2

Have you configured them to be a parallel set using the system configuration tools? Did you set them to switch as a group?

This is how it should be done:

1 Like
3

Hi Nick,

Thanks a lot for your reply. Yes, they are configured in parallel and operate together as a group — they switch, invert, and charge in sync.

I’m just wondering if the behavior I described is considered normal.

Thank you in advance,
SebastiĂ 

4

If configured normally, no, one should not remain connected if the other disconnects.

Perhaps post the full system configuration file.

5

We’ve seen this a bunch of times with our Quattro 10k’s as well. LOM type B.

My assumption is that it’s difficult to properly detect loss of grid (by frequency shifting) when there’s still a path to the grid via the one inverter still connected to the grid.

Also, I believe only the phase master does LOM detection.

6

Hi Nick,

Configuration file attached.

ConfigurationParallel.vms (256 Bytes)

Best regards,

SebastiĂ 

7

Even disconecting the Master’s AC input the system keeps charging when outputs are connected.

8

Yes, that was more of an informative point. The path back to grid still exists via the slave unit.

9

Config appears corrupt.

Can’t open it.