Stabilization of a Synchronous Machine Through Ooutput Feedback Control

Stabilization of a synchronous machine through the control of its exciotation is discussed in this paper. The control laws are derived from the linearized equation of performance of the synchronous machine by the minimization of a scalar performance index. The manipulated variable is an increment to the exciter reference voltage having an amplitude constraint. Control laws are dependent on the selection of the weighting coefficients of the states and the input. Guidelines are given for the selection of these coefficients so that both the small signal dynamic performance and the large signal transient performance of the machine are improved. It is shown that suboptimal controls corresponding to the feedback of machine slip velocity and its derivatives produce substantial improvement of machine response. Different transient conditions are simulated on the nonlinear machine model and the extent of improvement of machine performance by using the proposed control laws is demonstrated.