Variable structure output feedback control with application to a chemical process and a power system

A class of output feedback controllers capable of reducing parameter sensitivities and rejecting disturbances and parameter variations is investigated in this thesis. The methodology uses piecewise continous output feedback controllers, generating a sliding output trajectory along a switching manifold in the output space. Variable structure output feedback controllers are developed which guarantee stability of all motions of a class of linear time-invariant systems. Two coordinate transformations are used which makes the design procedure easier to implement. New switching surface design algorithm based on eigenvectors assignment technique is presented. Besides using the output variables, the output feedback controllers presented in this thesis ensure minimum chattering effect during sliding. This is because the control gains of the switched part may be chosen relatively small. In order to demonstrate the applicability of the presented results, and to compare the obtained results with the existing ones, the design method is applied to a chemical process and to a power system. The power system is represented by a single machine connected to an infinite bus. The control design method used in the chemical process problem serves as an intermediate step between state variable structure control and output variables variable structure control since the design process utilizes only the available outputs of the plant