Differential flatness theory‐based approach to the control of gas‐turbine electric power generation units

Abstract

A differential flatness theory-based control and state estimation method has been developed for electric power units that consist of synchronous generators connected to gas turbines. The dynamic model of the power unit satisfies the properties of differential flatness and this allows for its transformation into an input–output linearized form. Moreover, it is shown that the state-space description of the power system can be written in the canonical (Brunvsky) form. Using this, a solution for the power unit's control and state estimation problem is given. First, a stabilizing feedback controller is designed. Moreover, with the use of differential flatness theory-based implementation of the Kalman Filter it becomes possible to solve the state and disturbances estimation problem of the gas-turbine power unit. The considered filtering method, under the name of Derivative-free nonlinear Kalman Filter, consists of application of the Kalman Filter's recursion on the linearized equivalent model of the power system, and of an inverse transformation that allows for computing estimates for the state variables of the initial nonlinear system. By redesigning the aforementioned Kalman Filter as a disturbance observer one can also identify and annihilate in real time exogenous perturbations.