Performance Analysis of Fractional Order PID Controller with the Conventional PID Controller for Bioreactor Control

Abstract — Despite the dramatic advancement of process control in recent decades, the proportional-integral-derivative (PID) controller continues to be the most frequently used feedback controller today. PID control mechanism, the ubiquitous avail ability of reliable and cost effective commercial PID modules, and pervasive operator acceptance are among the reasons for the success of PID controllers. An elegant way of enhancing the performance of PID controllers is to use fractional-order controllers where I and D-actions have, in general, non-integer orders. In a PIλDδ controller, besides the proportional, integral and derivative constants, denoted by Kp, Ti and Td respectively, we have two more adjustable parameters: the powers of s in integral and derivative actions, viz. λ and δ respectively. This paper compares the performance of conventional PID and fractional PID controllers used for bio-reactor control.