A High Reliability Variable-Speed Constant-Frequency Generator for Ram Air Turbines

"Present ram air turbine (RAT) generators use variable blade pitch geometry to maintain constant speed to produce constant frequency electrical power. The variable blade pitch control and actuation systems have poor demonstrated reliability and add weightand cost to the generation system. RAT generator such as this are used to power the RADAR jamming pod (AN/ALQ99) presently carried by the EA-6B Prowler aircraft; the only airborne electronic warfare capable asset for the joint armed services. This proposalseeks to develop a variable-speed constant-frequency (VSCF) generator and electronics package which when coupled to a RAT with fixed blade pitch will result in a more reliable, lower system weight/size, and less costly solution for producing constantfrequency electrical power. The proposed generator system employs permanent magnet technology and reduced-rating power electronics to achieve these goals. This allows the RAT to be operated nearer its ideal aerodynamic operating speeds in variable windconditions. This Phase I project will result in analytical development of candidate designs with comparison to the present product solution and other competing alternatives. A follow on Phase II will result in prototype hardware design, fabrication, andtesting. Phase III will produce RAT generator systems for military platform installation and testing. The results of this research will demonstrate the viability and benefits of a VSCF generat