Homopolar bearingless slice motors
AssigneeMassachusetts Institute of Technology
InventorsMinkyun Noh, David L. Trumper
Life of this patent
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Abstract
Described are homopolar bearingless slice motors which include an array arrangement of permanent magnets on stator teeth, and a magnet-free rotor having a unique surface geometry. Also described are related components of such motors. The permanent magnet arrays provide homopolar bias flux to the rotor, and salient features on the rotor surface route the bias flux toward paths desirable for force and torque generation. In an illustrative embodiment, two magnet arrays are placed at the tips of stator teeth, so as to provide the bias flux via relatively short flux paths. By modulating current through windings based upon the rotor radial and angular position measurements, the stator can levitate and rotate the rotor.
Claims22
A homopolar bearingless slice motor comprising:
- a stator comprising a stator armature and a stator winding, the stator armature having a plurality of stator teeth and the stator winding comprising a plurality of coils;
- an array of permanent magnets disposed on the stator teeth;
- and
- a magnet-free rotor comprising one or more salient features, wherein the one or more salient features comprise:
- a first radial fin projecting radially outward from a top surface of the magnet-free rotor, and a second radial fin projecting radially outward from a bottom surface of the magnet-free rotor, wherein the first and second radial fins are axisymmetric with respect to a rotational axis of the rotor and are continuous around the circumference of the rotor;
- and
- a plurality of rotor teeth distributed along a circumference of the magnet-free rotor and disposed on an outer surface of the magnet-free rotor and between the first and second radial fins of the magnet-free rotor.
A homopolar bearingless slice motor comprising:
- a magnet-free rotor comprising one or more salient features, the one or more salient features comprising:
- a first radial fin projecting radially outward from a top surface of the magnet-free rotor, and a second radial fin projecting radially outward from a bottom surface of the magnet-free rotor, wherein the first and second radial fins are axisymmetric with respect to a rotational axis of the rotor and are continuous around the circumference of the rotor;
- and
- a plurality of rotor teeth distributed along a circumference of the magnet-free rotor and disposed on an outer surface of the magnet-free rotor and between the first and second radial fins of the magnet-free rotor.
A method of operating a homopolar bearingless slice motor, the method comprising:
- rotating a magnet-free rotor comprising one or more salient features within a stator bore defined by a stator armature having a plurality of stator teeth, wherein the one or more salient features comprise:
- a first radial fin projecting radially outward from a top surface of the magnet-free rotor, and a second radial fin projecting radially outward from a bottom surface of the magnet-free rotor, wherein the first and second radial fins are axisymmetric with respect to a rotational axis of the rotor and are continuous around the circumference of the rotor;
- and
- a plurality of rotor teeth equally distributed along a circumference of the magnet-free rotor and disposed on an outer surface of the magnet-free rotor and between the first and second radial fins of the magnet-free rotor.
Dependencies are inferred from the claim text.