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 ?

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.

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.

FvM said:

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

Click to expand...

Thanks for good hint.

I can undetstand its perpose and effect.
https://www.mathworks.com/help/simulink/examples/anti-windup-control-using-a-pid-controller.html
https://en.wikipedia.org/wiki/Integral_windup