Decentralized output feedback controller design for the damping of electromechanical oscillations
This paper presents a new methodology for the design of damping controllers, based on a new formulation of the output feedback control problem, which is very well suited for the task of oscillation damping in power systems. With this new formulation, the design problem can be expressed directly in the form of linear matrix inequalities, for which there are fast numerical solvers available. Other advantages of the methodology are the use of the polytopic model for the power system, which provides robustness (with respect to the operating conditions) to the design process and the use of a regional pole placement criterion as a design objective, allowing the imposition of a minimum damping ratio for all modes of the controlled system. The designed controllers have no action when the system is in steady state, due to a particular modification made in the model equations (which does not augment the controller dimension). The obtained results show that the designed controllers are able to provide adequate damping for both local and inter-area modes. Moreover, no numerical problems were experienced in a design over a large power system model (compared to the typical models used for this kind of controller design).
damping controller damping ratio inter-area mode