Variable-speed constant-frequency generator system for aircraft

Abstract
Variable-speed constant-frequency (vscf) generator systems are studied as an extension of well-known vscf motor technology. The vscf generator systems become practical for aircraft main generating systems when the commutator function is performed by semiconductor devices. It is concluded that the best scheme for this application is one using as the main generator a wound rotor induction machine operated above and below synchronous speed, and a slip channel comprised of a semiconductor frequency changer and a synchronous machine driven by the variable-speed shaft.