A unity feedback system that uses proportional-integral (PI) control i...
Given unity feedback system is shown below,
Characteristic equation of unity feedback system is,
From the above equation it is clear that, the sufficient condition for the system to be stable is,
KP>(-1) and K1>0
The Routh table for above characteristic equation,
For stability or marginal stability of given system, the coefficient of first column of Routh table should be positive or same sign so,
Here, K I is a function of K P .
Now, double derivative of KI is,
It means, KI has maxima at K P = 4 .
Thus, maximum value of KI at K P = 4 will be,
Question_Type: 4