You could probably hack your inverter with a simple DPLL, to keep it in sync with the wall. I'm assuming you could interface with the clock generator (cap or re

You could probably hack your inverter with a simple DPLL, to keep it in sync with the wall. I'm assuming you could interface with the clock generator (cap or resistor), if you wanted to keep it "analog" :). Or, perhaps replace the existing clock with a microcontroller that you can sync with NTP or the 60Hz line.