Hello Aman,
As the documentation of the block suggests, it computes the optimal manipulated variable (mv) by solving a quadratic programming problem using either the default KWIK solver or a custom QP solver. You can read more about QP Solvers in the documentation link below which might give you more clarity on the modelling and mathematics behind it:
Regarding finding the disturbance model, please refer to the following documentations which should point you to the right direction:
Hope this helps!
