SMALL-SCALE PROTOTYPE OF A FULLY HTS-2G SIX-PHASE INDUCTION ELECTRICAL MACHINE

Abstract

HTS direct drive generators with high specific output mass power and specific output volume power (at the boiling point of liquid nitrogen 77 K) are needed for aviation. Elimination of the reduction unit will reduce the weight of the entire generation system. However, this puts high demands on the strength of the high-speed rotor. Other important requirements are: brushless; the possibility of adjusting the output voltage (by changing the excitation current) depending on the magnitude and type of the connected load; autonomy (no external power supply of excitation current). To satisfy all the above requirements, a fundamentally new technical solution for an electric machine was developed. The generator is a two-package hybrid of the Induction machine with combined excitation. HTS-2G windings (2x3-phases of HTS-2G armature windings and axial excitation coil) are in stationary cryostats on the stator. The rotor has alternating poles of high coercive permanent magnets and ferromagnetic poles. To ensure the alternating magnetic field of the poles of the rotor and to avoid demagnetization of permanent magnets by a counter-directed field of the axial excitation HTS coils, the rotor packages are rotated by one pole. In this case, the demagnetizing part of the axial flux is intercepted by the ferromagnetic pole of the neighboring packet.