Hello again, everyone. I did some further online research and it
appears modern inverters use fast-switching insulated-gate bipolar
transistors (IGBTs) in sine-wave and modified sine-wave inverter
designs. My guess is that a microprocessor controls IGBT firing times
as well as engine speed (in an inverter generator) as AC output loads
increase and therefore demand more DC at inverter input. The
microprocesser itself would rely on a crystal as the reference time base
(frequency) source which would ultimately determine the inverter's
output frequency (e.g. 60 or 50 Hz +/- some acceptable deviation). So
the crystal has to remain reasonably stable in a variety of operating
environments. Sincerely,
--
J. B. Wood e-mail: