1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

PM Synchronous motor Id-Iq current control

  1. Mar 18, 2015 #1
    Hi everyone,

    I am trying to implement the current control (Id, Iq) of a four pole PM synchronous motor. I am having trouble in making the Iq current follow a set reference.


    I had also implemented a cascaded speed control for a dc motor.


    In that case, I adjusted the gains of the PI controller (inner loop/current loop) by stalling the motor and checked if the motor current followed the set reference current. It worked in this way for the dc motor. I thought of doing the same way for Iq but I am not getting the expected results.

    In delta configuration of the stator, if I make the integral gain to be zero, the motor does not rotate. The motor starts rotating if I increase the integral gain to 1 and the speed increases as I increase the integral gain and reaches the maximum value depending upon the supply voltage.
    If I stall the motor at different speeds, I get different values of Iq, say for 30 rad/s I have a current of 30mA and 60 rad/s, it is 50mA.
    The motor current (Iq) is not following the reference current for any change I am making in the Kp and Ki values

    Is there any other approach to achieve the PI control for both the currents?

  2. jcsd
  3. Mar 21, 2015 #2
    Your images can only be viewed with an edaboard account.
  4. Mar 22, 2015 #3
    Sorry about that!
    Should have checked the links after posting them..anyways they are below..

    Fig 1


    Fig 2

  5. Mar 23, 2015 #4
    Have you checked that the basics of your system work, e.g. making sure you can produce a current vector in the stator-fixed reference frame (αβ-components) that follows some reference? If that works, then you can start worrying about the rotor-fixed reference frame.

    In general, if you represent your system as a hierarchy of components, you start at the root, test it through and through, and then you can start building atop of it. In your case, the root could be a sampling system, with the reference-frame transformations built atop of it.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook