Synthesis of optimal regulator for synchronous machine

A procedure for the synthesis of a self-adaptive near-optimal controller for small perturbations, subject to a quadratic performance index, of a synchronous generator connected to an infinite busbar is described. The performance of the system with this controller is compared with those having proportional and derivative voltage regulators. The optimal controller extends the stable operating region of the system at low active-power levels, increases the magnitudes of perturbations for which the actual nonlinear system is stable, improves the transient response and reduces the steady-state deviations for a step change in the infinite-busbar voltage.