Hi,
You can test the quality of the power the generator is producing.
This protocol was suggested by mexicowanderer whom I have the greatest respect for:
TEST: Shore power versus alternative power. Put glass of water in microwave and start, if voltage drops to 109 vac or less at same outlet as microwave is plugged into, end of test. Energy source is inadequate.
Stage 2 Same glass of water, start at room temperature with oven thermometer. Set timer for one minute high. Remove glass measure temperature on shore power
Stage 3 Do the same with alternative power source and compare temperature difference to test above.
If there is a large temperature difference, then your microwave is going to unlove you trying to suffer through inadequate voltage or waveform.