I have a system of iQ7 inverters now, and hope to add an EnPower switch and EnCharge battery when they become available, so I have been researching this gear for a while now. The Enphase Ensemble will not work in a 3 phase system, at least not when it is released.
What are your single phase and 3 phase voltages there? Here we have 120-0-120 (240) sinlge phase, and our 3 phase is 120-120-120 from neutral and 208v across legs. In Europe, I dealt with 220-220-220 and 384 across legs. In a non ensemble system, the microinverters operate at 190-250 volts, so in a 120/208 3 phase system, they would be wired across 2 phases, a-b, b-c, or c-a respectively. In a single phase setup like I have here in the USA, they are all connected from line to line at 240 volt. Most of my loads are single leg 120 volt and it depends on the line transformer to equalize the load if there is more current on one leg than the other. If you are at 220/384 3 phase, your setup should work.
But if you have a 120/208 3 phase setup, jumping the 3 phases together would literally be shorting the output of all of the inverters. You could drop to using 2 legs in a single phase arrangement, but this is where you end up just using that 1/3 of the microinverters. The rest of them are going to the now dead leg.
Another possibility would be using a much more complex transfer switch. Add a single phase panel that feeds your important loads that need to be backed up. When the 3 phase power is available, 2 legs can feed that panel. And when there is a power failure, the generator can feed it as well.
The new iQ8 inverters will be able to supply power during an outage also, so you could then use the switch arrangement to move the solar panels and microinverters to the backup single phase panel. They big benefit to the iQ8 is that they will be able to lower their current output to match the load you are using, so the power island voltage will not go to high when the load is reduced. My iQ7’s are not fast enough to do that, so I need to have at least one iQ8 for every iQ7 for this to be able to work.
By late December, we will have a lot more info available about the Enphase iQ8 and the new EnCharge batteries.
My current system has 16 iQ7’s. If I add 2 EnCharge 3 batteries (they each contain 4 iQ8 inverters), then I just need to swap out 4 more of my iQ7’s for iQ8’s and I will have 12 iQ7’s and 12 iQ8’s.
