Quantitative Feedback Theory design of valve position control for co-ordinated superheater control of main steam temperatures of power plant boilers

Abstract

Abstract This paper presents an application of a Single-Input Single-Output (SISO) controller and a Valve Position Controller (VPC) using robust Proportional-Integral (PI) controllers designed using Quantitative Feedback Theory (QFT) specifications to control superheater outlet steam temperatures of a 600MW once-through boiler. To illustrate the methodology, a dynamic model of a tower-type boiler was modelled using Flownex® to test the VPC design application with structured uncertainty under varying load and disturbance conditions. The results show that the valve position controller application is more efficient than the SISO technique, allowing the final attemperator more bandwidth to deal with unexpected temperature changes.