# US 10,767,691 B2 · Magnetic bearing

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- Number: US 10,767,691 B2
- Document ID: US10767691B2
- Status: Granted
- Kind: B2
- Application number: 15/548,613
- Filed: 2016-02-15
- Published: 2018-08-23
- Granted: 2020-09-08
- Earliest claimed: 2015-02-26
- Assignees: Carrier Corporation
- Applicants: Carrier Corporation
- Inventors: Jagadeesh K. Tangudu; Parag M. Kshirsagar
- Web page: https://patentgrep.com/patent/US10767691B2

## CPC

- F16C 32/0465: {with permanent magnets provided in the magnetic circuit of the electromagnets}
- F16C 32/044: {Active magnetic bearings}
- F16C 32/0459: {Details of the magnetic circuit}
- F16C 32/0461: {of stationary parts of the magnetic circuit}
- F16C 32/0468: {of moving parts of the magnetic circuit, e.g. of the rotor}
- F16C 32/0485: {with active support of three degrees of freedom}
- H02K 7/09: with magnetic bearings
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})

## Abstract

A magnetic bearing (20) comprises: a rotor (22) to be supported for rotation about an axis (502); a stator (24) extending from a first end (30) to a second end (32) and comprising: one or more first permanent magnets (110); one or more second permanent magnets (112) of polarity substantially opposite to a polarity of the one or more first permanent magnets; at least three radial windings (40,42,44,46); a first axial winding (34); a second axial winding (36); a first end pole (120); and a second end pole (122).

## Claims

### Claim 1

A magnetic bearing (20) comprising:
a rotor (22) to be supported for rotation about an axis (502);
a stator (24) extending from a first end (30) to a second end (32) and comprising:
one or more first permanent magnets (110);
one or more second permanent magnets (112) of polarity substantially opposite to a polarity of the one or more first permanent magnets;
at least three radial windings (40,42,44,46);
a first axial winding (34);
a second axial winding (36);
a first end pole (120); and
a second end pole (122),
wherein:
the rotor comprises a metallic core (160, 28) carrying an axially laminated metallic jacket (150); and
the first end pole and second end pole extend radially inboard of an inner diameter surface of the axially laminated metallic jacket.

### Claim 2 (depends on 1)

The magnetic bearing of claim 1 wherein:
the at least three radial windings (40,42,44,46) are wound on at least one center core (50, 52, 54, 56).

### Claim 3 (depends on 2)

The magnetic bearing of claim 2 wherein:
the at least one center core comprises a center laminate (50, 52, 54, 56);
a center back iron (70, 72, 74, 76) is radially outboard of the center laminate;
a first end laminate (130) is axially outboard of the center laminate;
a first end back iron (132) is radially outboard of the first end laminate;
a second end laminate (140) is axially outboard of the center laminate oppositely to the first end laminate; and
a second end back iron (142) is radially outboard of the second end laminate.

### Claim 4 (depends on 1)

The magnetic bearing of claim 1 wherein the at least three radial windings comprise:
three radial windings angularly offset at 120° intervals.

### Claim 5 (depends on 1)

The magnetic bearing of claim 1 wherein the at least three radial windings comprise:
a first pair of diametrically opposite radial windings (40, 42); and
a second pair of diametrically opposite radial windings (44, 46).

### Claim 6 (depends on 5)

The magnetic bearing of claim 5 wherein:
the second pair of radial windings is orthogonal to the first pair.

### Claim 7 (depends on 5)

The magnetic bearing of claim 5 wherein the first pair of radial windings and the second pair of radial windings each comprise:
a first radially-open winding (40, 44); and
a second radially-open winding (42, 46).

### Claim 8 (depends on 7)

The magnetic bearing of claim 7 wherein:
each winding of the first pair of radial windings and the second pair of radial windings and the first axial winding and the second axial winding is electrically connected to a respective H-bridge amplifier.

### Claim 9 (depends on 5)

The magnetic bearing of claim 5 further comprising:
one or more laminate stacks (50, 52, 54, 56) extending through the coils of the first pair of radial windings and the second pair of radial windings.

### Claim 10 (depends on 1)

The magnetic bearing of claim 1 wherein:
the first axial winding and the second axial winding are connected in series to pass current in opposite angular directions.

### Claim 11 (depends on 1)

The magnetic bearing of claim 1 wherein:
the one or more first permanent magnets is a first permanent magnet ring; and
the one or more second permanent magnets is a second permanent magnet ring.

### Claim 12 (depends on 11)

The magnetic bearing of claim 11 wherein:
the first permanent magnet ring is a first continuous full annulus ring; and
the second permanent magnet ring is a second continuous full annulus ring.

### Claim 13 (depends on 11)

The magnetic bearing of claim 11 wherein:
the first permanent magnet ring comprises at least three circumferential segments; and
the second permanent magnet ring comprises at least three circumferential segments.

### Claim 14 (depends on 1)

The magnetic bearing of claim 1 wherein the stator further comprises:
a central back iron (70, 72, 74, 76) between the one or more first permanent magnets and the one or more second permanent magnets;
a first end back iron (132) axially outboard of the one or more first permanent magnets; and
a second end back iron (142) axially outboard of the one or more second permanent magnets.

### Claim 15 (depends on 1)

A method for using the magnetic bearing of claim 1, the method comprising running current through:
the at least three radial windings;
the first axial winding;
the second axial winding,
so as to:
control axial force or position by simultaneously powering the first axial winding and the second axial winding; and
control radial force or position by powering the at least three radial windings.

### Claim 16 (depends on 15)

The method of claim 15 wherein:
the at least three radial windings are powered by at least two H-bridge amplifiers; and
the first and second axial windings are powered by at least one H bridge amplifier.

### Claim 17 (depends on 15)

The method of claim 15 wherein:
the at least three radial windings are each powered by a respective associated H-bridge amplifier; and
the first and second axial windings are each powered by a respective associated H-bridge amplifier.

### Claim 18

A magnetic bearing (20) comprising:
a rotor (22) to be supported for rotation about an axis (502);
a stator (24) extending from a first end (30) to a second end (32) and comprising:
one or more first permanent magnets (110);
one or more second permanent magnets (112) of polarity substantially opposite to a polarity of the one or more first permanent magnets;
at least three radial windings (40,42,44,46);
a first axial winding (34);
a second axial winding (36);
a first end pole (120); and
a second end pole (122),
wherein in central longitudinal half-section centrally through one of the at least three radial windings:
a first radial flux loop (540, 542, 544, 546) or reverse thereof:
passes radially outward through a central laminate of the stator passing within said one of the at least three radial windings;
turns axially outboard in a central back iron;
passes axially outboard through the one or more first permanent magnets;
turns radially inward within a first end back iron;
passes radially inward through a first end laminate stack;
jumps a radial gap to pass radially through a rotor laminate stack;
turns axially inward axially inboard of the rotor laminate stack;
turns radially outward to pass back through the rotor laminate stack; and
jumps the radial gap to complete the first radial flux loop;
a first axial flux loop (550, 552, 554, 556) or reverse thereof:
passes radially through the first end laminate stack;
turns axially outboard through the first end back iron;
passes axially outward, turns and passes radially inward, and then turns and passes axially inward within the first end pole;
jumps the axial gap between the first end pole and the rotor axially inboard of the rotor laminate stack;
turns radially outward to pass back radially outward through the rotor laminate stack; and
jumps the radial gap to complete the first axial loop; and
a first PM bias axial flux loop (530, 532, 534, 536) or reverse thereof:
passes radially outward through the central laminate of the stator passing within the first of the diametrically opposite windings;
turns axially outboard in the central back iron;
passes axially outboard through the one or more first permanent magnets;
passes axially outboard through the first end back iron;
turns radially inward and then axially inward within the first end pole;
jumps an axial gap between the first end pole and the rotor axially inboard of the rotor laminate stack;
turns radially outward to pass back through the rotor laminate stack; and
jumps the radial gap to complete the first PM bias axial flux loop.

### Claim 19 (depends on 18)

The magnetic bearing of claim 18 wherein in said central longitudinal half-section:
a second radial flux loop is disposed with axial symmetry across a transverse centerplane, of path but not necessarily direction, to the first radial flux loop;
a second axial flux loop is disposed with axial symmetry across the transverse centerplane, of path but not necessarily direction, to the first axial flux loop; and
a second PM bias axial flux loop is disposed with axial symmetry across the transverse centerplane, of path but not necessarily direction, to the first PM bias axial flux loop.

### Claim 20

A magnetic bearing (20) comprising:
a rotor (22) to be supported for rotation about an axis (502) and having a rotor laminate stack (150);
a stator (24) extending from a first end (30) to a second end (32) and comprising:
one or more first permanent magnets (110);
one or more second permanent magnets (112) of polarity substantially opposite to a polarity of the one or more first permanent magnets;
at least three radial windings (40,42,44,46);
a first axial winding (34);
a second axial winding (36);
a first end pole (120);
a second end pole (122);
a first axial gap (200) between the first end pole and a first end (162) of rotor material (160) radially inboard of an inner diameter surface of the rotor laminate stack (150); and
a second axial gap (202) axially opposite the first axial gap between the second end pole and a second end (164) of the rotor material.

### Claim 21

A magnetic bearing (20) comprising:
a rotor (22) to be supported for rotation about an axis (502) and having a rotor laminate stack (150);
a stator (24) extending from a first end (30) to a second end (32) and comprising:
one or more first permanent magnets (110);
one or more second permanent magnets (112) of polarity substantially opposite to a polarity of the one or more first permanent magnets;
at least three radial windings (40,42,44,46);
a first axial winding (34);
a second axial winding (36);
a first end pole (120);
a second end pole (122);
one or more first end laminate stacks (130) and one or more first end back irons (132) between the first permanent magnet and first end pole;
one or more second end laminate stacks (140) and one or more second end back irons (142) between the second permanent magnet and second end pole;
a center laminate (50, 52, 54, 56); and
a radial gap between the rotor laminate stack (150) and the center laminate, one or more first end laminate stacks, and one or more second end laminate stacks.

### Claim 22 (depends on 21)

The magnetic bearing of claim 21 wherein:
the first end back iron (132) is radially outboard of the first end laminate; and
the second end back iron (142) is radially outboard of the second end laminate.