Constant-Frequency A-C power using variable speed generation

THE USUAL approach to provide a constant-frequency alternating-current electric power system is to drive a generator at constant speed, thus producing output power at constant frequency. Numerous methods have been devised for obtaining constant frequency power from a generator running at variable speeds. Analysis of these systems have shown the vast majority of these methods to be impractical for one reason or another, the usual problem being that an excess amount of power is required for generator excitation.