ULTRA HIGH TEMPERATURE 20 KHZ INDUCTION GENERATOR FOR VSCF OPERATING MODE

AN ULTRA HIGH TEMPERATURE BRUSHLESS ELECTRICAL GENERATING MODULE FOR 20 KHZ SPACE POWER SYSTEMS IS PROPOSED USING AN AZIMUTHALLY CASCADED, INTERNALLY-EXCITED INDUCTION GENERATOR(IEIG) OPERATING AT 44,000 RPM MAXIMUM SHAFT SPEED. THE UPPER OPERATING TEMPERATURE OF THE ROTOR IS IN THE RANGE 400-600 DEGREE(C). THE MODULE PROVIDES A CONSTANT FREQUENCY OUTPUT AT A VARIABLE TURBINE INPUT SPEED OVER A RANGE 1.5:1. A DISTINCT ADVANTAGE OF IEIG IS THE INHERENT RELIABILITY OF THE ROTOR CONSTRUCTION AND THE DIRECT STATOR OUTPUT. UNLIKE CONVENTIONAL VSCF ROTORS WHICH UTILIZE PERMANENT MAGNET MATERIALS, THE IEIG ROTOR IS A SOLID FORGING OF ALLOY CU/INCONEL 718 YIELDING A MONOLITHIC, CYLINDRICAL STRUCTURE WITHOUT SALIENCY OR SLOTTING. THE ROTOR IS CONTINUOUSLY MAGNETIZED BY THE DC-COMPONENT OF INDUCED CURRENT INITIATED BY THE STATOR "EXIT-EDGE" EFFECT CAUSING SELF-EXCITATION OF THE UNIT. IN PHASE I, A 15 KVA, 28 POLE AZIMUTHALLY CASCADED IEIG IS PROPOSED FOR DEMONSTRATION OF 20 KHZ, 30 OUTPUT. THIS TECHNOLOGY IS OFFERED AS AN ALTERNATIVE TO SOLID STATE POWER CONDITIONING. POWER DENSITY ACHIEVEABLE AT THE FULL SCALE LEVEL IS 6-10 KVA/KG. THE SYSTEM IS APPLICABLE TO EITHER CW OR PULSED MODE.