Design of a robust linear optimal regulator for synchronous generator excitation control

This paper presents a technique for designing generating units linear optimal regulators with extended stability region around nominal operating points. The technique uses a stability robustness criterion for the selection of the relative weights between the control effort and the system state regulation In the linear regulator quadratic performance index. The resulting regulator is stability robust in the sense of tolerating a specified set of unit parameter variations. By proper specification of the parameter variations, a robust linear optimal regulator Is obtained which guarantees unit stability in an extended region of operation around a given operating point. Example results are presented to substantiate the proposed technique by application to the design of a linear optimal regulator for a generating unit excitation system.