An Optimal Multivariable Controller With Application to Steam Temperature Control in a Boiler

Abstract

An optimal multivariable controller has been designed for superheater steam temperature control in a drum boiler. The controller takes the form of a linear quadratic regulator with supplementary states for added integral action. By means of a nonlinear model of the power plant, the performance of the controller is compared with that of the existing plant control system which consists of a set of PI controllers with feedforward action. The simulation results indicate that the superior performance of the digital controller justifies the expense of a control system retrofit.