The problem of synthesizing a field voltage controller for a synchronous generator is considered. Using the theory of feedback linearization of nonlinear systems, the existence of a linearizing feedback for an improved reduced-order three-dimensional model of a generator is proved and the most simple form of this feedback is derived. An application of the obtained nonlinear control law to synchronous generator stabilization gives very good results, not only for the reduced-order model but also for the ’exact’ Park’s model of a generator. Simulations of fault and post-fault transients in the obtained control system with the synchronous generator (P = 360 MW), in the presence of a nonlinear state observer and field voltage limiters confirmed superiority of this control system as opposed to a system with a linear optimal controller.