Controlling Three Phase Induction Motor

Using Arduino Motors, Mechanics, Power and CNC
1

Hey everyone!

For a university project my team and I have to build a motor. We are wanting to build a three phase induction motor controlled by Arduino. The plan is to have the Arduino Uno output three sine waves that are out of phase by 120 degrees. These sine waves will then be amplified by op-amps to drive the motor. What I need help with is the code. I would like both the amplitude and the frequency of the output signals to be variable via potentiometers. The frequency variable from roughly 20 Hz to 120 Hz and the output amplitude from ~0 to ~3V. Is there any example code kicking around for something like this?

Thanks!

2

That's absolutely not the way to do this. You need 3 phase PWM signal driving
a 3-phase bridge.

Motors are never driven analog, always from switched / PWM, so that the power
goes to the motor, not your massive heatsink.

[ Incidentally the same software approach works for either, since you
use DDS and sine-table lookup in each case ]

3

BTW you might want to look at the code in post #24 in this thread: PWM for 3-phase Inverter - Motors, Mechanics, Power and CNC - Arduino Forum

4

Hmm, I've read in quite a few other places that this general idea should work. I just haven't been able find one where the motor being controlled is three phase. The output of the Arduino would be PWM.

A three phase motor just requires three voltage separated by 120 degrees. So if I can get the Arduino to output three voltages separated by 120 degrees, albeit at too low a power to drive the motor, and then amplify those three voltages, wouldn't that work? I'm trying to keep things simple.

I will read up on three phase bridges, as you suggested.

Thanks!