Controller gain

Discussion in 'General Electronics Chat' started by hovik, May 16, 2011.

  1. hovik

    Thread Starter Member

    Sep 21, 2009
    I am tuning some PI-controllers in MATLAB Simulink experimentally. For some of the controllers I can see that the higher the proportional gain (for a spesific set integral time), the better reference tracking. The thing though is that after a certain value, the improvement in reference tracking speed is very small, compared to how much I need to increase the gain.

    My question is; in real life, what will limit the possible controller proportional gain? Are there any rules to at which point the increase of controller speed is not sufficient for increasing the proportional gain (economically or physically)?

    Any comments are appreciated!
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    Increasing proportional gain can lead to instability under certain conditions.

    The conventional approach to reducing steady state error to zero with a constant control input is to introduce additional integral control to the existing proportional control within the control loop.