EP-4742513-A1 - AXIAL FLUX MACHINE AND STATOR FOR AXIAL FLUX MACHINE

EP4742513A1EP 4742513 A1EP4742513 A1EP 4742513A1EP-4742513-A1

Abstract

A stator for an axial flux machine. The stator comprises a plurality of units disposed generally circumferentially around an axis. Each of the units is operable to generate a magnetic field generally parallel to the axis. Each of the units respectively comprises: an axially extending stator core tooth defining at least part of a stator core, and a set of windings wound around the stator core tooth. The stator comprises a heat dissipation arrangement for facilitating dissipation of heat from the stator core during operation of the stator. By facilitating dissipation of heat generated or accumulated in the stator core during operation of the stator, the performance, efficiency and/or lifespan of the stator can be improved.

Inventors

WANG, KUEI YUNG
CHEN, YU-TING
NGUYEN, QUANG ANH

Assignees

Chang Gung International Energy Inc.

Dates

Publication Date: 20260513
Application Date: 20241106

Claims (15)

A stator for an axial flux machine, comprising: a plurality of units disposed generally circumferentially around an axis, each of the units being operable to generate a magnetic field generally parallel to the axis and respectively comprises: an axially extending stator core tooth defining at least part of a stator core; and a set of windings wound around the stator core tooth; and a heat dissipation arrangement for facilitating dissipation of heat from the stator core during operation of the stator.
The stator of claim 1, wherein the heat dissipation arrangement comprises: for at least one of the units, one or more materials thermally coupled between the stator core and a corresponding set of windings to enable or facilitate heat conduction between the stator core and the corresponding set of windings.
The stator of claim 2, wherein the one or more materials comprises a thermally conductive and electrically insulating material; and optionally, the thermally conductive and electrically insulating material comprises a potting material.
The stator of claim 2 or 3, wherein the one or more materials is arranged at least partly in or fills a gap between the stator core tooth and the corresponding set of windings.
The stator of claim 4, wherein the set of windings is provided by a wire; and wherein the one or more materials is further arranged at least partly in a space between adjacent turns of the wire.
The stator of claim 5, wherein a ratio of a width of the space between adjacent turns of the wire to a cross sectional width of the wire is between about 1:1 to about 2:1, where the width of the space and the cross sectional width are both in a direction parallel to the axis.
The stator of any one of claims 4 to 6, wherein the one or more materials is arranged such that part of the corresponding set of windings is exposed.
The stator of any one of claims 2 to 7, wherein each of the at least one unit with the one or more materials comprises: an electrically insulating material arranged between the stator core tooth and the one or more materials.
The stator of any one of claims 1 to 8, wherein at least one of the units comprises: a first stator core shoe arranged at a first axial end of the stator core tooth, and a second stator core shoe arranged at a second axial end of the stator core tooth; wherein the first stator core shoe and the second stator core shoe define part of the stator core; wherein an inner surface of the first stator core shoe, an inner surface of the second stator core shoe, and a surface of the stator core tooth together define a channel; and wherein at least part of the inner surface of the first stator core shoe is exposed and/or at least part of the inner surface of the second stator core shoe is exposed to provide the heat dissipation arrangement.
The stator of claim 9, wherein the inner surface of the first stator core shoe comprises a radially innermost portion defining a radially innermost end and a radially outermost portion defining a radially outermost end; wherein the exposed part of the inner surface of the first stator core shoe comprises the radially innermost portion and/or the radially outermost portion; and wherein the radially innermost end is closer to the axis than a radially innermost end defined by components received in the channel; and/or the radially outermost end is further away from the axis than a radially outermost end defined by components received in the channel.
The stator of claim 9 or 10, wherein the inner surface of the second stator core shoe comprises a radially innermost portion defining a radially innermost end and a radially outermost portion defining a radially outermost end; wherein the exposed part of the inner surface of the second stator core shoe comprises the radially innermost portion and/or the radially outermost portion; and wherein the radially innermost end is closer to the axis than a radially innermost end defined by components received in the channel; and/or the radially outermost end is further away from the axis than a radially outermost end defined by components received in the channel.
The stator of any one of claims 9 to 11, comprising: a stator housing receiving the plurality of units and comprising a first wall including one or more first cavities each receiving a respective first stator core shoe; wherein the heat dissipation arrangement comprises, for each of the one or more first cavities, at least one opening arranged at a location corresponding to the first cavity to expose at least part of an outer surface of the first stator core shoe; and optionally, the at least one opening for the first cavity comprises an opening having substantially the same shape and center as, and a smaller size than, an outer surface of the corresponding first stator core shoe.
The stator of claim 12, wherein the stator housing comprises a second wall including one or more second cavities each receiving a respective second stator core shoe; and wherein the heat dissipation arrangement comprises, for each of the one or more second cavities, at least one opening arranged at a location corresponding to the second cavity to expose at least part of an outer surface of the second stator core shoe; and optionally, the at least one opening for the second cavity comprises an opening having substantially the same shape and center as, and a smaller size than, an outer surface of the corresponding second stator core shoe.
The stator of claim 1, wherein each of the units comprises: a first stator core shoe arranged at a first axial end of the stator core tooth, and a second stator core shoe arranged at a second axial end of the stator core tooth; wherein the first stator core shoe and the second stator core shoe define part of the stator core; wherein the stator further comprises a stator housing receiving the plurality of units and comprising: a first wall including first cavities each receiving a respective first stator core shoe, and a second wall including second cavities each receiving a respective second stator core shoe; wherein the heat dissipation arrangement comprises, for each of the units: one or more materials thermally coupled between the stator core and a corresponding set of windings to enable or facilitate heat conduction between the stator core and the corresponding set of windings; at least part of an inner surface of the first stator core shoe that is exposed; at least part of an inner surface of the second stator core shoe that is exposed; for each of the first cavities, an opening arranged at a location corresponding to the first cavity to expose part of an outer surface of the first stator core shoe; and for each of the second cavities, an opening arranged at a location corresponding to the second cavity to expose part of an outer surface of the second stator core shoe.
An axial flux machine comprising: at least one of the stator of any one of claims 1 to 14; and at least one rotor.

Description

TECHNICAL FIELD Embodiments disclosed herein relates to an axial flux machine and a stator for an axial flux machine. BACKGROUND GB2585357A and GB2619413A have disclosed some existing axial flux machines. During operation, heat may be generated or accumulated in various components of the axial flux machine (e.g., its stator), e.g., due to resistive loss, magnetic loss, stray loss, friction and mechanical loss, etc. This heat, if not properly and timely dissipated, may undesirably affect the performance, efficiency, and/or lifespan of the axial flux machine. SUMMARY In a first aspect, there is provided a stator for an axial flux machine. The stator comprises a plurality of units disposed generally circumferentially around an axis. Each of the units is operable to generate a magnetic field generally parallel to the axis. Each of the units respectively comprises: an axially extending stator core tooth defining part of a stator core, and a set of windings wound around the stator core tooth. The stator comprises a heat dissipation arrangement for facilitating dissipation of heat from the stator core (at least the stator core tooth) during operation of the stator. By facilitating dissipation of heat generated or accumulated in the stator core (at least the stator core tooth) during operation of the stator, the performance, efficiency and/or lifespan of the stator (and hence the axial flux machine) may be improved. For example, overheat damages to stator components (e.g., stator housing, adhesives used in the stator) can be reduced. For example, the duration in which the axial flux machine can maintain peak power during operation can be increased. In one embodiment, the heat dissipation arrangement comprises: for at least one of the units, one or more materials thermally coupled between the stator core (at least the stator core tooth) and a corresponding set of windings to enable or facilitate heat conduction (i.e., heat transfer by conduction) between the stator core (at least the stator core tooth) and the corresponding set of windings. The one or more materials may be arranged in one or more layers. By enabling or improving heat conduction between the stator core and the corresponding set of windings in at least one of the units, heat generated or accumulated in the stator core during operation of the stator may be dissipated more quickly and/or more effectively. In an example in which the stator is yokeless (i.e., the stator cores of the units are not in thermal contact with a yoke and are not in thermal contact with each other), heat conduction between the stator core and the corresponding set of windings may be particularly useful for facilitating heat dissipation from the stator core. In one embodiment, the heat dissipation arrangement comprises: for each respective one of the units, one or more materials thermally coupled between the stator core (at least the stator core tooth) and a corresponding set of windings to enable or facilitate heat conduction between the stator core (at least the stator core tooth) and the corresponding set of windings. The one or more materials of different units may be separated (i.e., not in direct contact with each other). The one or more materials of different units may be the same (i.e., same composition) or different (i.e., different compositions). In one embodiment, the one or more materials comprises a thermally conductive and electrically insulating material. For example, the one or more materials may consist only of the thermally conductive and electrically insulating material. For example, the one or more materials may include at least one other material (in addition to the thermally conductive and electrically insulating material). In one embodiment, the thermally conductive and electrically insulating material comprises a potting material. The potting material may include a potting compound (e.g., epoxy-resin, with or without additive for improving thermal conductivity). The potting material can provide not only thermal conduction and electrical insulation between the stator core (at least the stator core tooth) and the set of windings, but may also provide improved mechanical strength, improved vibration or shock resistance, improved corrosion protection, and/or improved chemical protection for the stator. In one embodiment, the one or more materials is arranged (e.g., disposed) at least partly in a gap between the stator core tooth and the corresponding set of windings. In one embodiment, the one or more materials is filled (substantially completely) in the gap. The one or more materials in the gap may provide a more uniform and/or more effective thermal coupling between the stator core tooth (or more generally the stator core) and the corresponding set of windings. This may be particularly useful for stator in which the gap between the stator core tooth and the corresponding set of windings that is sized and/or shaped such that coolant fluid (e.g., gas or liquid