> Is it possible to design a single phase VFD to control speed
> of motors - 220VAC, 1Ph, 50 Hz, 2kW?  The designs I've
> found are controllers for 3 phase motors.

Hi Mohit. This topic has been covered before, and at that time
the conclusion was that designing such a circuit is fraught with
difficulties. IIRC, the only way was to rectify the AC and then
convert the HV DC back to AC at the new frequency. I'd have
been interested myself in such a speed control, as all the ones
I've seen have been either 3-phase, expensive, or both. Apart
from tools, I've a few synchronous motors that could use VFD

> I've used triac based controllers, but want something with
> better control

Only my lathe and drill press use synchrounous motors, and
they are the only ones to use belt selection for speed control.
All of the rest I can use with a pretty standard SCR controller
(I've a gif of the circuit if you want to take a look)

I can't say I've found it lacking in any great respect. It has
feedback to keep the torque up as much as possible, and is
OK at slower speeds. This particular one doesn't hunt too
much either. As well as the material you also have bear in mind
the cutting edge. I can imagine a 20krpm router bit run at slow
speed would not do such a clean job, but you probably know
that anyway

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