Proportional, Integral and Derivative (PID) controller are most widely used controller in chemical process industries because of their simplicity, robustness and successful practical application. Many methods have been proposed for design of Multi-loop PI/PID controller for Multi-Input Multi-Output (MIMO) process. In this paper we have compared two methods for two by two processes with time delays. One is model order reduction and other is without reduction. Performance index and robustness has been used as the criterion for comparison. Several commonly used simulation examples are included for demonstrating effectiveness of the proposed methods and the results obtained are comparatively same.
PID controller design for load frequency control: Past, Present and future challenges
