Flywheel energy storage with PM, induction, or variable reluctance machine
An integrated flywheel energy storage device includes an inner stator having an interior support component and multiple stator cores connected to the interior support component, each with an associated stator coil arranged in multiple electrical phases. An outer rotor housing supports multiple active rotor poles which each face inward toward the stator cores, the active rotor poles being permanent magnets, copper relining, an induction squirrel cage, or variable reluctance poles. A vacuum containment housing surrounds the outer rotor housing. The outer rotor housing has a rotational moment of inertia that stores kinetic energy as a kinetic battery, allowing the device to deliver multi-phase electrical power when required. High power density is achieved by integrating the flywheel into the outer rotor housing. The device additionally functions as a gyroscope for stabilizing an exterior structure, or as a gyroscopic reference for navigational purposes when supported on a gimballed platform.
1. An electrical energy storage system comprising:
an inner stator defining a centerline, the inner stator including:
a non-ferromagnetic interior stator support component comprising:
a stationary bushing defining a center region; and
a plurality of spokes projecting outward from the center region toward a plurality of stator cores connected to the non-ferromagnetic interior support component; and
a plurality of stator coils, each of the plurality of stator coils being disposed on each of the plurality of stator cores; and
an outer rotor axially disposed along the centerline and around the inner stator, the outer rotor comprising:
a rotor housing; and
a plurality of active rotor poles supported by the rotor housing, wherein:
each of the plurality of active rotor poles is disposed on the interior of the outer rotor housing;
the plurality of active rotor poles are arranged proximate to the plurality of stator cores;
each of the plurality of stator cores defines an active top, outer, and bottom stator core surface; and
each of the plurality of active rotor poles defines an active top, outer, and bottom rotor surface proximate the active top, outer, and bottom stator core surface, respectively, such that the outer rotor at least partially surrounds the plurality of stator cores; and
a power control circuit, the power control circuit electrically connected to the plurality of stator coils;
wherein:
the outer rotor housing is configured to produce rotational torque on the outer rotor housing from electrical power supplied to the plurality of stator coils, thereby increasing a rotational speed of the outer rotor housing and converting electrical energy into rotational kinetic energy;
the plurality of stator coils are configured to produce electrical power from rotational kinetic energy in the outer rotor housing, thereby decreasing the rotational speed of the outer rotor housing and converting rotational kinetic energy into electrical energy; and
the power control circuit configured to:
produce a multi-phase variable frequency waveform from an electrical power input, wherein the frequency varies directly with the rotational speed of the outer rotor housing; and
energize the plurality of stator coils with the multi-phase variable frequency waveform, when the electrical energy storage system is operating in an energy storage mode; and
receive a multi-phase variable frequency waveform from the plurality of stator coils; and
produce electrical power output from the multi-phase variable frequency waveform, when the electrical energy storage system is operating in an energy delivery mode.
2. The integrated flywheel energy storage device of claim 1 , wherein:
the outer rotor has a mass;
the inner stator has a mass; and
the ratio of the outer rotor mass to the inner stator mass is greater than 1.
3. The electrical energy storage system of claim 1 , wherein the active rotor poles are selected from the group consisting of permanent magnets, rotor cage, copper relining, and variable reluctance poles.
4. The electrical energy storage system of claim 1 , wherein:
the outer rotor surrounds at least half of combined surfaces of the active top, outer, and bottom stator cores;
the active rotor poles are concentrated parameter active rotor poles; and
each of the concentrated parameter active rotor poles has three active surfaces comprising the active top, outer, and bottom rotor surfaces.
5. The integrated flywheel energy storage device of claim 1 , wherein the outer rotor surrounds at least half of combined surfaces of the active top, outer, and bottom stator cores.
6. The integrated flywheel energy storage device of claim 1 , wherein each of the plurality of stator cores is comprised of a ferromagnetic material selected from the group consisting of ferromagnetic tape and stacked ferromagnetic layers.
7. The integrated flywheel energy storage device of claim 1 , wherein the outer rotor housing is comprised of a material selected from the group consisting of fiberglass and an alloy of metal.
8. The electrical energy storage system of claim 1 , further comprising an exterior structure, wherein:
the integrated flywheel energy storage device is configured to have an angular momentum;
the integrated flywheel energy storage device is configured to provide angular momentum support to the exterior structure; and
the exterior structure is a building, a vehicle, a ship, or another machine.
9. The electrical energy storage system of claim 8 , further comprising:
a gimbal support assembly;
a gyroscopic reference sensor; and
a gyroscopic reference connector.