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    PI Controler with Limiter

    See attached figure.
    I think this is basically PI Controler with Limiter.

    Here difference of input and ouput of Limiter is fed back to integral input.

    What effect can I expect from this feedback ?

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    Re: PI Controler with Limiter

    It's an anti-windup circuit that clamps the integrator output at the actual limits of the manipulated value.

    I think, it's called anti-windup back calculation method.



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    Re: PI Controler with Limiter

    This should have no impact on the bode plot but in some of these special cases should make the system come out of saturation more gracefully. I only see this coming into play in a couple instances.

    First if the limit changes while the system is saturated it would correct the integrator accordingly.

    Second if its a large system with a lag time between the PI controller and the system component that detects the limit. In this case the 'extra' windup can be backed out.

    EDIT: Third if the system takes large steps and may jump well over a limit.

    Any others?

    I design systems with such a lag because I design generic controllers whose output needs to be scaled etc before going to a modulator block which understands and applies limits. There are a handful of clock delays in this path which allow the integrators to wind up a little extra. Though I haven't seen evidence it causes problems.



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    Re: PI Controler with Limiter

    Quote Originally Posted by FvM View Post
    It's an anti-windup circuit that clamps the integrator output at the actual limits of the manipulated value.
    Thanks for good hint.

    I can undetstand its perpose and effect.
    https://www.mathworks.com/help/simul...ontroller.html
    https://en.wikipedia.org/wiki/Integral_windup



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