# Induction motor in state space

Discussion in 'Math' started by kokkie_d, Nov 24, 2010.

1. ### kokkie_d Thread Starter Active Member

Jan 12, 2009
72
0
Hi,

From literature the induction motor has been well described in state space, see attachment- Induction Motor-01.jpg:

This equation describes the induction motor with a rotating rotor.

To describe a rotating stator as a consequence of the 3 phase supplied power, the following equation can be used, see attachment - induction motor - rotorary frame -02.jpg:

Now, my question is the following:

I have a little difficulty understanding the second equation, the one showing the inclusion of the rotorary stator frame.
Because when I simulate a power supply (through the use of 3 combining 3 sine waves set 120 degrees apart)
$
3 phase = A*(sin(\omega t+\theta) + sin(\omega t+\theta+2\pi/3) + sin(\omega t+\theta - 2\pi/3))
$

then I can control the amplitude by adjusting A and the speed by adjusting f within $\omega$ and any start angle by $\theta$.

This should give me control of the motor by adjusting its power supply and I would not need the rotorary frame reference?

On the other hand if I use the rotorary frame reference I only need to control the amplitude of the signal and the speed within the stator, right?

Are my last statements true?

cheers,

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