Tesla Motors Club
I'm having 2 Powerwalls installed and was wondering if anyone here knows how the Powerwalls and their Gateway control/manage my existing 2 Sunnyboy 7000 Inverters? Solar Grid-Tie inverters are designed as current sources since they push all the power the panels can produce out into the PG&E grid and don't have the ability to be throttled. Tesla is pairing each of my Sunnyboy 7000s with one Powerwall 2. When in backup mode with the grid disconnected, the inverters produce their maximum power which is used to power my house and charge the batteries. But when the batteries are fully charged and the inverter power cannot be used, they must be shut down "somehow". The Powerwalls or the Gateway must have some mechanism to fool the inverters into shutting down.
As far as I can see on the schematic they gave me, it does not appear the Powerwalls are able to disconnect each Sunnyboy inverter using the UL1741 shutdown. The only trick I can think of would be if the Powerwalls shift the frequency of the AC off 60Hz so the Sunnyboy solar inverter sees this as a fault and shuts down. I cannot see any other AC "inband" method ( voltage, frequency, wave-shape etc..) and the Sunnyboys don't offer and other shutdown method.
Current source inverters raise their voltage gradually and slightly above the grid voltage such that their current is forced out into the grid. But if there is no grid or power "sink" and the power cannot be used, it will keep raising the voltage until it goes into a fault. I cannot see how Tesla can be sure that "any" grid tie inverter as a current source will behave properly when there is no ability to sink the current into the home or battery charging. Does anyone know how the solar inverters are managed/controlled once charging is complete and there is nowhere to use the power?
As far as I can see on the schematic they gave me, it does not appear the Powerwalls are able to disconnect each Sunnyboy inverter using the UL1741 shutdown. The only trick I can think of would be if the Powerwalls shift the frequency of the AC off 60Hz so the Sunnyboy solar inverter sees this as a fault and shuts down. I cannot see any other AC "inband" method ( voltage, frequency, wave-shape etc..) and the Sunnyboys don't offer and other shutdown method.
Current source inverters raise their voltage gradually and slightly above the grid voltage such that their current is forced out into the grid. But if there is no grid or power "sink" and the power cannot be used, it will keep raising the voltage until it goes into a fault. I cannot see how Tesla can be sure that "any" grid tie inverter as a current source will behave properly when there is no ability to sink the current into the home or battery charging. Does anyone know how the solar inverters are managed/controlled once charging is complete and there is nowhere to use the power?