Nonlinear State and Unmeasured Disturbance Estimation for Use in Power Plant Superheaters Control

This paper deals with the state and unmeasured disturbance estimation within the nonlinear model predictive control of the superheated steam temperature in a once-trough boiler of a fossil fuelled power plant. The nonlinear model of the once-trough boiler has very high order, it is significantly nonlinear and load dependent. Model is excited by several disturbances, but not all of them are measured. Particularly the heat of flue gas is unmeasured disturbance which has significant influence on the superheated steam temperature and its estimation could improve the control performances of the superheated steam temperature. The proposed nonlinear state and unmeasured disturbance observer is based on the nonlinear moving horizon estimation algorithm. © 2015 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of DAAAM International Vienna.