Level Control using Bode’s Integral

Abstract

PID controllers are widely used in industrial plants. Usually a first or a second order model with time delay is used. Many a times even if the plant model is perfectly known, it leads to a set of nonlinear equations for which no analytic solution is available. An advanced method tries to find a solution by numerical methods or to simplify the equations using some approximations to find an analytic solution. The main drawback of these approaches is that the desired specifications are not achieved on the real systems. Bode's Integral can be used in such cases. It requires only the knowledge of amplitude and the phase of the system at the given frequency and the system static gain.

Keywords:  PID controllers, Bode's Integral