Electromechanical flywheels
An electromechanical flywheel machine includes a flywheel mass and a motor-generator having a rotor rotatable about a stationery inner stator having stator windings.
1. A flywheel assembly comprising:
a flywheel surround assembly including a space for receiving a flywheel mass, the assembly defining upper and lower support planes:
a motor-generator stator hanging from the upper plane, defining an axis of rotation, having a field coil encircling the axis, and having an armature coil about perpendicular to the field coil;
a hollow motor-generator rotor in the form of a cylinder with an open end and an opposite end coupled to a hub;
the rotor open end receiving the stator into the rotor hollow, the rotor for rotation about the axis;
the flywheel mass surrounding and coupled to the rotor;
a lower electromagnetic bearing (EMB 1 ) supported from the lower plane, EMB 1 for exerting uplifting and centering forces on the rotor;
an upper electromagnetic bearing (EMB 2 ) supported from the upper plane, EMB 2 for exerting centering forces on the rotor,
a plurality of three or more stator rings (SR 1 , SR 2 , SR 3 . . . ), each ring encircling the axis and the plurality of rings having a slotted periphery;
the field coil located between a pair of rings;
the armature coil interengaged with slots in each of the rings;
at least three stator rings (SR 1 , SR 2 , SR 3 );
between a first pair of adjacent stator rings (SR 1 , SR 2 ), each one of a first plurality of pole assemblies for completing a magnetic path therebetween; and,
between a second pair of adjacent stator rings (SR 2 , SR 3 ), each one of a second plurality of pole assemblies for completing a magnetic path therebetween;
wherein no magnetic path exists between pole assemblies in the first plurality of pole assemblies and no magnetic path exists between pole assemblies in the second plurality of pole assemblies.
2. The flywheel assembly of claim 1 wherein the pole assemblies are affixed to a non-magnetic support structure.
3. The flywheel assembly of claim 2 wherein the hub includes a conical transition piece.
4. The flywheel assembly of claim 3 further including a drag pump situated within the evacuable space.
5. The flywheel assembly of claim 4 wherein the stator includes a stator ring that is an electromagnetic bearing stator.
6. The flywheel assembly of claim 5 wherein the rotor includes an electromagnetic bearing rotor.
7. The flywheel assembly claim 1 further comprising:
multiple rotor stages spaced apart along the axis;
viewed with the axis of rotation oriented horizontally,
in a first stage a first “Z” shaped pole assembly adjacent to a first “S” shaped pole assembly and
in a second stage a second “S” shaped pole assembly adjacent to a second “Z” shaped pole assembly;
the first “Z” shaped pole assembly adjacent to the second “S” shaped pole assembly; and,
the first “S” shaped pole assembly adjacent to the second “Z” shaped pole assembly;
wherein each pole assembly provides a staggered magnetic path for completing a magnetic circuit interconnecting adjacent stator rings.
8. The flywheel assembly of claim 7 wherein the pole assemblies are affixed to a non-magnetic support structure.
9. The flywheel assembly of claim 8 wherein the hub includes a conical transition piece.
10. The flywheel assembly of claim 9 further including a drag pump situated within the evacuable space.
11. The flywheel assembly of claim 10 wherein the stator includes a stator ring that is an electromagnetic bearing stator.
12. The flywheel assembly of claim 11 wherein the rotor includes an electromagnetic bearing rotor.