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FAQ: Micro Inverter AC or DC power management

QUESTION:  I wish to manage the MicroInverter installation and to regulate the total output power. If use current relays to control the power generated back to grid, is it better to disconnect the AC (230V) output input or the DC input (40V) from the solar panel?  I also wonder if the AC side switching could damage the MicroInverter because of the frequent on&off switching.  Also I am afraid to loose energy if the MicroInverter needs to start (synchronize) each time for a few seconds after re-connection of the AC side. Please explain which is the best.

Answer: Both DC and AC disconnection is possible. The AC disconnection is recommended for the management of higher power ratings, since it is easier to turn-on/off the AC currents (less sparking for AC).  See an example of an AC disconnection here.

The DC disconnection is a solution for power management of small power ratings, e.g. connection of individual panels to the micro-inverter. See an example of the DC disconnection here.

For the switching limits:  There is no technical limit for the AC switching. Actually the AC current is “switching” 50 times per second because it is alternating at 50 Hertz.

For the energy loss at reconnection times: Please note that energy is measured in KILOWattHOURS (kWh). One 1 kWh is 3 600 000 Watt/seconds. If you loose few hundreds watts for some seconds, the actual loss is in fact very small.

In summary: the AC switching is the regular solution for the MicroInverter installation power management.