Tuning of PI controllers for self-regulating processes
Journal
Journal of the Chinese Institute of Chemical Engineers
Journal Volume
28
Journal Issue
5
Pages
x2-327
Date Issued
1997
Author(s)
Abstract
One simple tuning method for controlling self-regulating processes using the Proportional-Integral (PI) controllers is proposed in this article. The process dynamics are modeled as a first-order-plus-dead-time transfer function, Gp(s) = Ke-ds/(τs + 1), by any existing identification method such as the closed-loop reaction-curve method of Chen (1989, 1991). The process dynamics would be classified into three categories: lag dominant, dead-time dominant, and small dead-time, according to the relative magnitude of time constant and dead-time in the model. The PI controller settings are then determined for each of these three process characteristics by using the Internal Model Control (IMC) principle. These proposed PI controller tuning rules are: Kc = 1 1 τ/ 2 Kmax(d,0.5) (%/%) τ1 = {min{τ,6d} if d > 0.5 3 if d > 0.5 (min) Several numerical examples are given to demonstrate the effectiveness and the robustness of the proposed tuning method on a large class of self-regulating processes.
Subjects
Identification
IMC
Pl Controller
Tuning
Type
journal article