Axial gap electrical machine

• US 7,098,566 B2
• Filed: 10/05/2001
• Issued: 08/29/2006
• Est. Priority Date: 05/24/2001
• Status: Expired due to Fees

• Current Assignee: Mmillenniumm Group Incorporated
• Original Assignee: Arjuna Indraes Waran Rajasingham
• Inventors: Rajasingham, Arjuna Indraes Waran
• Primary Examiner(s): Le, Dang
• Application Number:
  US09/971,035
• Publication Number:
  US 20020175588A1
• Time in Patent Office: 1,789 Days
• Field of Search: 310201-208, 310/256, 310/196, 310/268, 310/266
• US Class Current: 310/208
• CPC Class Codes: H02K 1/2795 the rotor consisting of two or more circumferentially positioned magnets
• CPC Class Codes: H02K 1/32 with channels or ducts for flow of cooling medium
• CPC Class Codes: H02K 21/24 with magnets axially facing the armatures, e.g. hub-type cycle dynamos
• CPC Class Codes: H02K 3/04 Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
• CPC Class Codes: H02K 3/28 Layout of windings or of connections between windings windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32
• CPC Class Codes: H02K 3/47 Air-gap windings, i.e. iron-free windings
• CPC Class Codes: H02K 3/50 Fastening of winding heads, equalising connectors, or connections thereto
• CPC Class Codes: H02K 41/03 Synchronous motors; Motors moving step by step; Reluctance motors H02K41/035 takes precedence
• CPC Class Codes: H02K 7/083 radially supporting the rotary shaft at both ends of the rotor H02K7/086, H02K7/09 take precedence
• CPC Class Codes: H02K 7/12 with auxiliary limited movement of stators, rotors or core parts, e.g. rotors axially movable for the purpose of clutching or braking
• CPC Class Codes: H02K 9/00 Arrangements for cooling or ventilating channels or ducts in parts of the magnetic circuit H02K1/20, H02K1/32; channels or ducts in or between conductors H02K3/22, H02K3/24
• CPC Class Codes: Y10T 29/49071 by winding or coiling

Abstract

An axial gap electrical machine employs unique architecture to (1) overcome critical limits in the air gap at high speeds, while maintaining high torque performance at low speeds, while synergistically providing a geometry that withstands meets critical force concentration within these machines, (2) provides arrangements for cooling said machines using either a Pelletier effect or air fins, (3) “windings” that are produced as ribbon or stampings or laminates, that may be in some cases be arranged to optimize conductor and magnetic core density within the machine. Arrangements are also proposed for mounting the machines as wheels of a vehicle, to provide ease of removing and installing said motor.

Claims

1. An electrical machine with an axis of rotation between a magnetic field element (102/103 FIG. 1, FIG. 9) with a plurality of pairs of poles, each pair of poles arranged to provide a substantially axial magnetic field between members of said pairs of poles in a direction substantially parallel to the axis of rotation of said electrical machine, and wherein said plurality of pairs of poles are arranged to be around a circle about the axis of rotation of said electrical machine, and wherein said magnetic field element is supported by a first support element;

and at least one internally self braced toroidal wound element (101 FIG. 1) comprising a first toroid of rotation and a second toroid of rotation, each with a radial direction and each coaxial with the axis of rotation of said electrical machine (147 A,B FIG. 16 A), said at least one toroidal wound element mechanically supported at one or both of its external and internal peripheries by a second support element, and comprising a plurality of interlocking windings (FIGS. 2J, 2S, 10C, 13C) wherein each of said windings has a first end and a second end (111c of FIGS. 2J, 2S, 10C, 13C), and each comprising a contiguous flat insulated conductor with a length, and a width (“

w”

FIG. 2C) and a thickness (“

t”

FIG. 2C) at each point along said length, and wherein the width is greater than the thickness at each point along said length, and said conductor having a first and second face across said thickness along said length of said conductor, and wherein said conductor comprises at least one pair of working segments along its length, each of said working segments oriented such that the width of the conductor along the length of said working segments lies substantially in the direction of said substantially axial magnetic field (FIGS. 2M, 2T, 10C, 13C), and wherein for all windings of said at least one wound element, the first face of said contiguous conductor for each winding, along each element of the at least one pair of working segments is a first face of respectively each element of the at least one pair of working segments and faces substantially in the local direction of motion of said working segment in the electrical machine, and wherein the second face of said contiguous conductor for each winding, along each element of the at least one pair of working segments is a second face of respectively each of the elements of the at least one pair of working segments and faces substantially in the direction opposite the local direction of motion of said working segment in the electrical machine, and wherein said at least one pair of working segments comprise a first working segment and a second working segment, wherein the first working segment (148A FIG. 1) lies across the first toroid of rotation with its length along the radial direction of said first toroid of rotation and the second working segment (148B FIG. 1) lies across the second toroid of rotation with its length along the radial direction of said second toroid of rotation, and wherein the first working segment and the second working segment are arranged with a non-working segment of said conductor on either side thereof, thereby forming a turn of said winding with a first end and a second end, and wherein a space between each of the pairs of poles of the magnetic field element (102, 103), straddle and are separated by a pair of working airgaps (139) from the first and second toroids of rotation of the at least one wound element,

such that relative movement of the pairs of poles of said magnetic field element cause their magnetic field relative to the working segments in the at least one would element to generate an electromotive force across the working segments, and conversely such that when there is an electromotive force applied to the ends of the working segments, the induced current in the working segments and thereby in the magnetic field of the magnetic field element, create a force on the magnetic field element to cause its relative movement in a predetermined direction of rotation.

2. The electrical machine as in claim 1, comprising one internally braced toroidal wound element.

3. The electrical machine as in claim 1, with at least one internally braced toroidal wound element wherein said contiguous conductors comprise stranded flat conductor material.

4. The electrical machine as in claim 1, wherein said at least one internally braced wound element has a first and a second winding adjacent to each other in said wound element and each having a first end and a second end and wherein the second end of the first winding is connected to the first end of the second winding to change the number of turns of a combined winding per pole in said electrical machine wherein the topology of each turn of the combined winding is the same as that for each of the first and second windings.

5. The electrical machine as in claim 1, wherein said width of said working conductor segments change with radial distance along said working conductor segments from the axis of rotation of said machine (FIG. 1) thereby permitting control of the air gap with changes in the radius of the magnetic field element.

6. The electrical machine as in claim 5, wherein the assembled windings are machined together to a predefined cross section profile following assembly of said at least one wound element, thereby facilitating better airgap tolerances of the electrical machine when in operation.

7. The electrical machine as in claim 1, wherein each of said windings have at least one turn wherein a first turn is the turn following the first end of said contiguous conductor and a last turn is the turn preceding the second end of said contiguous conductor, along said contiguous conductor.

8. The electrical machine as in claim 7, wherein two of said windings are the first winding and the second winding, and wherein the second end of the last turn of the first winding is electrically attached to the first end of the first turn of the second winding thereby creating a series connection of turns in a combined winding wherein one face of the conductor in the first winding along its last turn and one face of the conductor in the second winding along its first turn lie substantially adjacent to each other along their lengths.

9. The electrical machine as in claim 7, wherein two of said windings are the first winding and the second winding, the first end of the first turn of the first winding is electrically attached to the first end of the first turn of the second winding and the second end of the last turn of the first winding is attached to the second end of the last turn of the second winding thereby creating a parallel connection of turns in said windings wherein one face of the conductor in the first winding along its last turn and one face of the conductor in the second winding along its first turn lie substantially adjacent to each other.

10. The electrical machine as in claim 1, wherein at least one of said working segments of said contiguous conductor have insulated magnetic core elements (FIGS. 2K, 2R, 10C, 13D) bonded on at least one of said two faces.

11. The electrical machine as in claim 10, wherein said insulated magnetic core elements are of length substantially equal to the width of said working segments, and oriented in a direction substantially parallel to the axis of rotation of said electrical machine, said core elements having small width and thickness, thereby minimizing eddy current losses in said core elements.

13. An electrical machine as in claim 10, wherein said wound element is machined to a predetermined cross section at each radial distance from the axis of rotation following assembly of said wound element.

14. An electrical machine as in claim 10, wherein said insulated core elements have an increasing thickness in the direction of the conductor thickness, with increasing radial distance along said working segments, thereby increasing the utilization of space in the winding with magnetic core material.

15. An electrical machine as in claim 1, wherein said magnetic field element is an armature and said wound element is a stator, and wherein an inclination of the airgap to the axial direction is utilized to control the width of said airgap by changing a radius of said armature.

16. An electrical machine as in claim 1, wherein said magnetic field element is a stator and the wound element is an armature.

17. An electrical machine as in claim 1, wherein said first support element is an axle with a degree of rotational freedom with regard to a housing of said electrical machine, and said second support element is the housing for said electrical machine wherein said second support element is attached to the toroidal wound element at its outer end.

18. An electrical machine as in claim 1, wherein said second support element is an axle and said first support element is a housing for said electrical machine with a degree of rotational freedom with regard to the axle of said electrical machine.

19. An electrical machine as in claim 1, further comprising a back iron entirely within said at least one wound element and between said first and second toroids of rotation of each of the at least one wound element.

20. An electrical machine as in claim 1 wherein said second support element is attached to flanges on a plurality of non working segments (FIG. 2K1) of the contiguous conductors of said at least one wound element providing one or both of structural support and thermal coupling for cooling, to said wound element.

21. An electrical machine as in claim 20 wherein at least one of said flanges is attached to a back iron element between the toroids of rotation of said working segments.

22. An electrical machine as in claim 1 wherein said second support element is attached as splines to splines slots created on said flanges of said non working segments of said windings in said at least one wound element.

23. An electrical machine as in claim 1 with at least one internally braced toroidal would element wherein said contiguous conductor comprise stranded flat conductor material.

24. An electrical machine as in claim 1, wherein said machine (FIG. 1, FIG. 16) is produced by:

Assembling the magnetic field element with a plurality of pole pairs (102, 103) arranged in a circle about the axis of rotation of said electrical machine, with an intervening axial gap between the poles of each pole pair sufficient for accommodating a pair of working airgaps and the at least one wound element (101) of said electrical machine there between (104);

Attaching said magnetic field element to the first support element;

Assembling the at least one wound element to be an annular ring, with a plurality of interlocking windings (FIGS. 2J, 2S, 10C, 13C) each with two end connectors;

Attaching said at least one wound element assembled to be an annular ring to a second support element;

Connecting said two end connectors of each of said windings to one of electrical sources and sinks;

Thereby building an electrical machine.

25. An electrical machine as in claim 24, wherein said at least one wound element is ground or otherwise machined to meet a predefined cross section related to a desired air gap of said electrical machine following attachment to said second support element.

26. An electrical machine as in claim 24, wherein attaching said magnetic field element to said first support element comprises attaching said magnetic field element to at least one bearing for rotation about the axis of rotation of said machine, and attaching said at least one wound element assembled to be an annular ring to a second support element comprises attaching said at least one wound element to an axle of said machine to support said annular ring.

27. An electrical machine as in claim 24, wherein attaching said magnetic field element to said first support element comprises attaching said magnetic field element to a rotating axle of said machine to support said annular ring, and attaching said at least one wound element assembled to be an annular ring to a second support element comprises attaching said at least one wound element to the housing of said machine.

28. An electrical machine as in claim 24, wherein said contiguous conductor in each of said windings has a 180 degree twist on each of said non working conductors.

29. An electrical machine as in claim 28, wherein a turn of each said windings (FIG. 2J) has a net zero twist along its length comprising two twists each of 180 degrees in opposite directions along each of the non-working segments of said contiguous conductors.

30. An electrical machine as in claim 28, wherein a turn of each of said windings (FIG. 2R) has a net 360 degree twist along its length comprising two twists of 180 degrees each along each of the non-working segments of the contiguous conductors of the turn.

31. An electrical machine as in claim 1, wherein the entire length of any line substantially parallel to the axis of rotation, substantially parallel to said width of conductors, and between said pair of working airgaps lies entirely within two working axially offset segments of respectively two contiguous conductors in said wound element and each turn of each winding in said wound element comprise the same topology.

32. The electrical machine as in claim 1, with at least one internally braced toroidal wound element wherein said contiguous conductor along each of said working segments comprise braided conductor material.

33. An electrical machine as in claim 1, wherein the first support element is attached to an axle of the electrical machine and the second support element is attached to the housing of the electrical machine, and wherein the width of said working conductor segments are monotonically increased with increasing radial distance along said working conductor segments from the axis of rotation of said machine.

34. An electrical machine as in claim 1, wherein the second support element is attached to an axle of the electrical machine and the first support element is attached to the housing of the electrical machine, and wherein the width of said working conductor segments are monotonically decreasing with increasing radial distance along said working conductor segments from the axis of rotation of said machine.

12. An electrical machine as in 10, wherein said insulated magnetic core elements comprise powdered magnetic core material, compacted and bonded to said working conductor segments, thereby providing low reluctance in the core magnetic material but high electrical resistance to minimize eddy current losses in said magnetic core material.

35. An electrical machine with local relative motion in the x-direction of a 3 dimensional space with x-, y-, and z-directions between

a magnetic field element (102/103 FIG. 1, FIG. 9) with a plurality of pairs of poles, each pair of poles arranged to provide a magnetic field between members of said pairs of poles substantially in a y-direction orthogonal to said relative motion of said electrical machine, and wherein said plurality of pairs of poles are arranged to be along the local direction of motion of said electrical machine, and wherein said magnetic field element is supported by a first support element;

and at least one internally self braced wound element (101 FIG. 1) comprising a first generated volume of working conductors with an x-, y-, and z-direction and a second generated volume of working conductors with an x-, y-, and z-direction, said at least one internally braced wound element being mechanically supported at one or both of its ends in the z-direction, by a second support element, and comprising a plurality of interlocking windings (FIGS. 2J, 2S, 10C, 13C), wherein each of said windings has a first end and a second end (111c of FIGS. 2J, 2S, 10C, 13C), and each comprising a contiguous flat insulated conductor with a length, and a width and a thickness at each point along said length, and wherein the width is greater than the thickness at each point along said length, and said conductor having a first and second face across said thickness along said length of said conductor, and wherein said conductor comprises at least one pair of working segments along its length, each of said working segments oriented such that the width of the conductor along the length of said working segments lies substantially in the direction of said magnetic field (FIGS. 2M, 2T, 10C, 13C), and wherein for all windings of said at least one wound element, the first face of said contiguous conductor for each winding, along each element of the at least one pair of working segments is the first face of respectively each element of the at least one pair of working segments and faces the local direction of motion of said working segment in the electrical machine, and wherein the second face of said contiguous conductor for each winding, along each element of the at least one pair of working segments is the second face of respectively each of the elements of the at least one pair of working segments and faces the direction opposite the local direction of motion of said working segment in the electrical machine, and wherein said pair of working segments comprise a first working segment and a second working segment, wherein the first working segment lies across the first generated volume of working conductors with its length substantially in the z-direction and the second working segment lies in the second generated volume of working conductors with its length substantially in the z-direction and wherein the first working segment and the second working segment are arranged with a non-working segment of said conductor on either side thereof, thereby forming a turn of said winding with a first end and a second end, and wherein a space between each of the pairs of poles of the magnetic field element (102, 103), straddle and are separated by a pair of working airgaps (139) from the first and second volumes of generation of working conductors of the at least one wound element,

such that relative movement of the pairs of poles of said magnetic field element cause their magnetic field relative to the working segments in the at least one would element to generate an electromotive force across the working segments, and conversely such that when there is an electromotive force applied to the ends of the working segments, the induced current in the working segments and thereby in the magnetic field of the magnetic field element, create a force on the magnetic field element to cause its relative movement in a predetermined direction.

36. The electrical machine as in claim 35, wherein at least one of said working segments of said contiguous conductor have insulated magnetic core elements (FIGS. 2K, 2R, 10C, 13D) bonded on at least one of said two faces.

37. The electrical machine as in claim 36, wherein said insulated magnetic core elements are of length substantially equal to the width of said working segments, and oriented in a direction parallel to the axis of rotation of said electrical machine, said core elements having small width and thickness, thereby minimizing eddy current losses in said core elements.

38. An electrical machine with local relative motion in the x-direction of the 3-dimensional space with x-, y- and z-directions, between:

a magnetic field element (102/103 FIG. 1, FIG. 9) with a plurality of pairs of poles, each pair of poles arranged to provide magnetic field between members of said pairs of poles substantially in a y-direction orthogonal to said relative motion of said electrical machine, and wherein said plurality of pairs of poles are arranged to be along a local direction of motion of said electrical machine, and wherein said magnetic field element is supported by a first support element;

and at least one internally self braced wound element (101 FIG. 1) comprising a plurality of windings each with a first end and a second end, and each with at least one turn, wherein each turn has two working conductors, and wherein each of said turns has a width and a thickness along each point along its length and wherein said width is greater than said thickness at each point along its length, and wherein said width along each of the working conductors of each of the turns lies in the direction of the magnetic field (y-direction), and wherein the turn adjacent to the first end of said winding is the first turn of the winding and the turn adjacent to the second end of the winding is the last turn of the winding, and wherein each of the turns of each of the windings have substantially identical geometries, thereby allowing assembly of each of said windings with each turn substantially adjacent to the next turn on said winding across the width of each of said turns, thereby creating substantially identical windings, and wherein the wound element may be assembled with the substantially identical windings with the first turn of at least all but one winding in said wound element, located adjacent to the last turn of another winding in said wound element.

39. An electrical machine as in claim 38, wherein all windings have equal number of turns and each winding has at least one turn and electrical connectors at each end, thereby allowing the same electrical phase or different electrical phases to be connected to adjoining windings, thereby creating a wound element with windings with a variable number of turns per pole and with substantially identical turn geometries and winding geometries.