How to configure the PID controller block for anti-windup in the "Prevent Block Windup in Multiloop Control" model?

According to the documentation in the which can be accessed by running below command in the command window of installed MATLAB R2019a version:

>> web(fullfile(docroot, 'simulink/slref/prevent-block-windup-in-multiloop-control.html'))

“If the PID controller tracks the output of the inner loop, then its output never exceeds the saturated inner-loop output. To achieve this tracking, connect the Saturation block output to the tracking input of the PID Controller." 

When I connect a sine wave input, the output of PID block exceeds the saturated output of Inner Loop block.

Why is this model not behaving according to the documentation? Am I doing something wrong?

Answer 1

[MathWorks Support Team]

In order to observe such behavior, you need to configure the block for anti-windup. This can be achieved by setting the output saturation limit of the PID controller to match the inner-loop saturation limits and activate an anti-windup mechanism. To read more on this topic please run the below command in the command window of installed MATLAB R2019a version: 

>> web(fullfile(docroot, 'simulink/slref/anti-windup-control-using-a-pid-controller.html'))

Note: Instead of going to the PID Advanced tab, go to the Output Saturation tab and apply the changes there.

After enabling the anti-windup mode, you should be able to observe the expected behavior where the output of the PID never exceeds the saturated output of the inner-loop.

Please follow the below link to search for the required information regarding the current release:

https://www.mathworks.com/help/