speed control of a IPM motor

Discussion in 'General Electronics Chat' started by fisa, May 25, 2012.

  1. fisa

    Thread Starter New Member

    May 15, 2012
    I was wondering how can I determine physically in rotor position of IPMASM in speed control scheme.
    And what is the difference between IM and IPMSM speed control technique?

  2. steveb

    Senior Member

    Jul 3, 2008
    One can always use an external rotary encoder on the shaft to directly measure position and speed. This works for any motor.

    A synchronous motor has speed directly related to frequency (only scaled by pole pairs per revolution).

    An IM is asynchronous, so the determination of speed and overall motor control is more difficult without a direct sensor. There are many established techniques for dealing with speed control of induction motors, and it is not a trivial topic.
  3. strantor

    AAC Fanatic!

    Oct 3, 2010
    I can't find an asynchronous IPM motor when I search. Everything IPM I can find is synchronous. Are we sure it's asynchronous? If it's synchrounous, you could know the rotor position by keeping track of the AC periods.
  4. steveb

    Senior Member

    Jul 3, 2008
    I noticed that too. I was assuming tht IPMASM was a typo, and that he meant IPMSM.