I am seeing an oscillation in the power production at the top of the power curve on sunny days. This is not an isolated incident. It seems to happen every time there is a sunny day. The power goes up and down by about 300W:
The oscillation is tied to the reporting interval of every five minutes. When I look at the individual inverters, what I see is that the fourth-generation inverters (M250s and M215IGs) each move up or down about 10 W every five minutes. (The third-generation M190s are NOT doing this because they are operating at maximum output power during these times.) I suppose this could just be normal hunting for the MPP, but what does not make sense is that all of the inverters are doing this in unison. Wouldn't it make more sense for the inverters to search on independent schedules?
I'm wondering if anyone else with Enphase microinverters is experiencing this behavior. If so, do you know what causes it? TIA.