A differential flatness theory-based control approach for steam-turbine power generation units

The article proposes flatness-based control and non-linear Kalman Filtering for power generation units comprising synchronous generators connected to steam turbines. It is shown that the dynamic model of this power system is a differentially flat one. This property signifies that all its state variables and its control inputs can be expressed as differential functions of selected state variables of it, the latter standing for the flat outputs of the system. This allows for its transformation into a linear canonical form in which the design of a feedback controller and the solution of the state estimation problem become possible. Moreover, by introducing a Kalman Filter-based disturbance observer it becomes possible to identify in real time the perturbation terms that affect the power system's model. Through the proposed flatness-based controller, fast and accurate tracking of all reference setpoints is achieved by the state vector elements of the power unit. Moreover, through the proposed Kalman Filter-based disturbances estimator the control loop is given additional robustness against modelling errors and external perturbations.