Application of a Robust Minimum-Order Observer to Control the Performance of an Uncertain Multivariable Boiler Unit

To obtain economic operation of power plant steam generators, output of mechanical energy must be balanced with the electrical load while maintaining the internal variables within desired ranges. During a boiler unit operation, dynamic variables such as drum pressure, steam temperature and water level of drum must be controlled to achieve an appropriate performance. In this paper, a linear time invariant (LTI) model of a boiler unit is considered where feed-water and fuel mass rates are the control inputs. Due to the inaccessibility of some state variables of boiler system, a robust minimum-order observer is designed to gain an estimate state of the true state. Real dynamic model of boiler unit may associate with parametric uncertainties. In this case, optimum region of poles of observer-based controller are found such that the robust performance of the boiler system against model uncertainties is guaranteed.