Experimental Cascaded Doubly Fed Variable Speed Constant Frequency Generator System

Brushless Variable Speed Constant Frequency (VSCF) electric power generation may be obtained using cascaded symmetrically wound machines. The feasibility of using these machines as the basis for a stand-alone aircraft generator system was investigated by the USAF Aero Propulsion Laboratory. The concept is attractive as the system operates without hydraulics and employs a solid state power converter which operates at a fraction of the system output power and frequency. These factors combine to offer a system of relatively low complexity with the potential for high-reliability operation. This paper will discuss the operation of the cascaded doubly fed VSCF generator system and microprocessor control unit.