Direct and indirect adaptive control for synchronous generator semiconductor´s excitation system

The paper discusses the stability problem of a synchronous generator connected to an infinite bus. From the comprehensive and systematic eigenvalue analysis of the simplified linearized mathematical model of the synchronous generator it is evident that the variations in the dynamics of the synchronous generators are considerable. Therefor the conventional power system stabilizers with fixed parameters do not ensure damping of the contemporary synchronous generators operating in modern power systems at peak performances. It was found out that the adaptive control represents the most logic choice for high performance power system stabilizers. In the paper a detailed survey of the available adaptive control concepts is presented. Featured is the possibility of application of (-) direct adaptive control, where a signal from controller is calculated directly without intermediate identification of the controlled plant, as well as (-) indirect adaptive control with separate identification of the controlled plant and the controller with variable parameters calculated from identified model.