VFD Circuit for wood pellet smoker auger feed motor

Thread Starter

Pellet Smoker

Joined Oct 2, 2015
Looking for a simple design to build a vfd for a single phase 110vac auger feed motor. This auger motor goes on my pellet grill. Pulls roughly 1.5 to 2 amps. Would like to get a max of 70HZ to speed this up when wanted/needed. No design to complicated for me. Any help would be appreciated.



Joined Jul 18, 2013
VFD's for 1ph induction motors do not work well, hence there is not many out there, they tend to drop out of run at low rpm and with load.
You may be better off looking at a treadmill/DC motor and a simple SCR drive such as KB/Baldor.


Joined Mar 14, 2008
As suggested it's likely easier to change the motor than to build a circuit to vary the line frequency.

If you still want to do a circuit for that then it would have to deliver about 300W at 110V @ 70Hz.
One reasonably efficient way is to rectify the line voltage to DC and use that to power a high frequency PWM circuit modulated with a 70Hz sinewave.
The PWM output circuit would need to generate about a ±160Vpp signal at 3A peak current, which is not a trivial design.
This PWM signal would be filtered by the motor inductance to give the 70Hz sinewave to the motor.