# US 2021/0242739 A1 · Two degree-of-freedom electromagnetic machine

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- Number: US 2021/0242739 A1
- Document ID: US20210242739A1
- Status: Published application
- Kind: A1
- Application number: 16/860,205
- Filed: 2020-04-28
- Published: 2021-08-05
- Earliest claimed: 2020-02-05
- Assignees: Honeywell International Inc.
- Applicants: Honeywell International Inc.
- Inventors: Renukaprasad N; Deepak Mahajan; Govind Yadav; Subhashree Rajagopal
- Web page: https://patentgrep.com/patent/US20210242739A1

## CPC

- H02K 3/28: Layout of windings or of connections between windings (windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32)
- H02K 16/04: Machines with one rotor and two stators
- H02K 1/14: Stator cores with salient poles
- H02K 1/165: {Shape, form or location of the slots}
- H02K 1/22: Rotating parts of the magnetic circuit
- H02K 1/27: Rotor cores with permanent magnets
- H02K 3/48: in slots
- H02K 3/52: Fastening salient pole windings or connections thereto
- H02K 3/521: {applicable to stators only}
- H02K 21/22: with magnets rotating around the armatures, e.g. flywheel magnetos
- H02K 41/0354: {Lorentz force motors, e.g. voice coil motors}
- H02K 2201/18: Machines moving with multiple degrees of freedom
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})

## Abstract

A two degree-of-freedom electromagnetic machine includes an inner stator, a plurality of stator windings, an outer stator, a voice coil winding, a rotor, a plurality of spin magnets, and a plurality of tilt magnets. The plurality of stator windings, when electrically energized, impart a torque on the rotor that causes the rotor to rotate, relative to the inner and outer stators, about a first rotational axis, and the voice coil winding, when electrically energized, imparts a torque on the rotor that causes the rotor to rotate, relative to the inner and outer stators, about a second rotational axis that is perpendicular to the first rotational axis.

## Claims

### Claim 1

A two degree-of-freedom electromagnetic machine, comprising:
an inner stator comprising an inner stator structure and a plurality of arc-shaped stator pole shoes, the inner stator structure comprising a main body and a plurality of spokes extending radially outwardly from the main body, the spokes spaced apart from each other to define a plurality of stator slots, each arc-shaped stator pole shoe having an inner surface and an outer surface, each arc-shaped stator pole shoe connected to a different one of the spokes;
a plurality of stator windings wound around the spokes extending through the stator slots;
an outer stator surrounding at least a portion of the inner stator, the outer stator having an outer stator inner surface and an outer stator outer surface;
a voice coil winding disposed on the outer stator inner surface;
a rotor spaced apart from, and disposed between, the inner stator and the outer stator, the rotor at least partially surrounding the inner stator and at least partially surrounded by the outer stator, the rotor having a rotor inner surface and a rotor outer surface and configured to rotate about a plurality of perpendicular axes;
a plurality of spin magnets coupled to the rotor inner surface; and
a plurality of tilt magnets coupled to the rotor outer surface.

### Claim 2 (depends on 1)

The machine of claim 1, wherein the arc-shape and spacing of the stator pole shoes define a spherical shape.

### Claim 3 (depends on 1)

The machine of claim 1, wherein:
the plurality of stator windings, when electrically energized, impart a torque on the rotor that causes the rotor to rotate, relative to the inner and outer stators, about a first rotational axis; and
the voice coil winding, when electrically energized, imparts a torque on the rotor that causes the rotor to rotate, relative to the inner and outer stators, about a second rotational axis that is perpendicular to the first rotational axis.

### Claim 4 (depends on 1)

The machine of claim 1, wherein the stator windings are wound in concentrated fractional slot-pole combinations.

### Claim 5 (depends on 1)

The machine of claim 1, further comprising:
a control coupled to the plurality of stator windings and to the voice coil winding, the control configured to control current magnitudes in the plurality of stator windings and in the stator voice coil winding to thereby control rotation of the rotor.

### Claim 6 (depends on 5)

The machine of claim 5, wherein the control is configured to supply the stator windings and the stator voice coil winding with alternating current (AC) voltages.

### Claim 7 (depends on 6)

The machine of claim 6, wherein:
the stator windings are configured as 3-phase windings;
the control is configured to supply the stator windings with a first AC voltage, a second AC voltage, and a third AC voltage; and
the first, second, and third AC voltages are 120-degrees (2π/3 radians) out of phase with each other.

### Claim 8 (depends on 1)

The machine of claim 1, wherein the inner stator and the outer stator each comprise a magnetically permeable material.

### Claim 9 (depends on 1)

The machine of claim 1, wherein the rotor at least partially comprises a magnetically permeable material.

### Claim 10 (depends on 1)

The machine of claim 1, wherein the rotor comprises:
an inner rotor structure having an inner surface and an outer surface; and
an outer rotor structure having an inner surface and an outer surface,
wherein the outer rotor structure surrounds the inner rotor structure, and the inner surface of the outer rotor structure physically engages the outer surface of the inner rotor structure.

### Claim 11 (depends on 10)

The machine of claim 10 wherein:
the spin magnets are coupled to the inner surface of the inner rotor structure; and
the tilt magnets are coupled to the outer surface of the rotor outer rotor structure.

### Claim 12 (depends on 11)

The machine of claim 11, wherein:
the spin magnets comprise a first number of dipole magnets;
the tilt magnets comprise a second number of dipole magnets; and
the first number is greater than the second number.

### Claim 13 (depends on 12)

The machine of claim 12, wherein the inner rotor structure and the outer rotor structure each comprise a magnetically permeable material.

### Claim 14 (depends on 11)

The machine of claim 11, wherein:
the spin magnets comprise a plurality of dipole magnets;
the tilt magnets comprise a Halbach array.

### Claim 15 (depends on 14)

The machine of claim 14, wherein:
the inner rotor structure comprises a magnetically permeable material; and
the outer rotor structure comprises a non-magnetic material.

### Claim 16

A two degree-of-freedom electromagnetic machine, comprising:
an inner stator comprising an inner stator structure and a plurality of arc-shaped stator pole shoes, the inner stator structure comprising a main body and a plurality of spokes extending radially outwardly from the main body, the spokes spaced apart from each other to define a plurality of stator slots, each arc-shaped stator pole shoe having an inner surface and an outer surface, each arc-shaped stator pole shoe connected to a different one of the spokes;
a plurality of stator windings wound around the spokes extending through the stator slots;
an outer stator surrounding at least a portion of the inner stator, the outer stator having an outer stator inner surface and an outer stator outer surface;
a voice coil winding disposed on the outer stator inner surface;
a rotor spaced apart from, and disposed between, the inner stator and the outer stator, the rotor at least partially surrounding the inner stator and at least partially surrounded by the outer stator, the rotor having a rotor inner surface and a rotor outer surface and configured to rotate about a plurality of perpendicular axes;
a plurality of spin magnets coupled to the rotor inner surface; and
a plurality of tilt magnets coupled to the rotor outer surface,
wherein:
the arc-shape and spacing of the stator pole shoes define a spherical shape,
the plurality of stator windings, when electrically energized, impart a torque on the rotor that causes the rotor to rotate, relative to the inner and outer stators, about a first rotational axis, and
the voice coil winding, when electrically energized, imparts a torque on the rotor that causes the rotor to rotate, relative to the inner and outer stators, about a second rotational axis that is perpendicular to the first rotational axis.

### Claim 17 (depends on 16)

The machine of claim 16, further comprising:
a control coupled to the plurality of stator windings and to the voice coil winding, the control configured to control current magnitudes in the plurality of stator windings and in the stator voice coil winding to thereby control rotation of the rotor.

### Claim 18 (depends on 17)

The machine of claim 17, wherein:
the stator windings are configured as 3-phase windings;
the control is configured to supply the stator windings with a first AC voltage, a second AC voltage, and a third AC voltage, respectively; and
the first, second, and third AC voltages are 120-degrees (2π/3 radians) out of phase with each other.

### Claim 19 (depends on 1)

The machine of claim 1, wherein the rotor comprises:
an inner rotor structure having an inner surface and an outer surface; and
an outer rotor structure having an inner surface and an outer surface,
wherein the outer rotor structure surrounds the inner rotor structure, and the inner surface of the outer rotor structure physically engages the outer surface of the inner rotor structure.

### Claim 20 (depends on 10)

The machine of claim 10 wherein:
the spin magnets are coupled to the inner surface of the inner rotor structure; and
the tilt magnets are coupled to the outer surface of the rotor outer rotor structure.