# US 12,191,731 B2 · Stator for an electric machine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,191,731 B2 - Document ID: US12191731B2 - Status: Granted - Kind: B2 - Application number: 17/847,664 - Filed: 2022-06-23 - Published: 2022-12-29 - Granted: 2025-01-07 - Earliest claimed: 2021-06-24 - Assignees: ETA Green Power Limited - Applicants: ETA Green Power Limited - Inventors: Liam Bowman; Henry Collings - Web page: https://patentgrep.com/patent/US12191731B2 ## CPC - H02K 3/47: Air-gap windings, i.e. iron-free windings - H02K 1/187: {to inner stators} - H02K 3/28: Layout of windings or of connections between windings (windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32) - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract A stator for interacting with magnets carried by a rotor of an electric machine, the stator comprising: an active region arranged to be aligned with the magnets carried by the rotor; a first inactive region and a second inactive region, wherein the first and second inactive regions are separated by the active region; and a slotless phase winding comprising a plurality of conductive elements, wherein each conductive element comprises a conductor provided in an insulating housing, and wherein the slotless phase winding is arranged in a serpentine structure comprising: a first active segment in which the conductive elements extend across the active region from the first inactive region to the second inactive region; a second active segment in which the conductive elements extend across the active region from the second inactive region to the first inactive region; and an inactive segment coupling the first active segment to the second active segment, wherein the inactive segment comprises a turn provided in the second inactive region, and wherein at least one of the conductive elements is twisted in the second inactive region. ## Claims ### Claim 1 A stator for interacting with magnets carried by a rotor of an electric machine, the stator comprising: an active region arranged to be aligned with the magnets carried by the rotor; a first inactive region and a second inactive region, wherein the first and second inactive regions are separated by the active region; and a slotless phase winding comprising a plurality of conductive elements, wherein each conductive element comprises a conductor provided in an insulating housing, and wherein the slotless phase winding is arranged in a serpentine structure comprising: a first active segment in which the conductive elements extend across the active region from the first inactive region to the second inactive region; a second active segment in which the conductive elements extend across the active region from the second inactive region to the first inactive region; and an inactive segment coupling the first active segment to the second active segment, wherein the inactive segment comprises a turn provided in the second inactive region, and wherein at least one of the conductive elements is twisted in the second inactive region; wherein the conductive elements extend straight and untwisted across the active region. ### Claim 2 (depends on 1) The stator of claim 1, wherein the plurality of conductive elements are substantially parallel with each other in the first and/or second active segment. ### Claim 3 (depends on 1) The stator of claim 1, wherein the conductive elements in the first active segment are substantially parallel to the conductive elements in the second active segment. ### Claim 4 (depends on 1) The stator of claim 1, wherein the slotless phase winding is a first slotless phase winding, and wherein the stator is a multi-phase slotless stator comprising a plurality of slotless phase windings. ### Claim 5 (depends on 4) The stator of claim 4, wherein the first active segment of the first slotless phase winding is offset from the second active segment of the first slotless phase winding in the active region. ### Claim 6 (depends on 5) The stator of claim 5, wherein each of the plurality of slotless phase windings is arranged in a serpentine structure, wherein the serpentine structure of the first slotless phase winding is interlaced with the serpentine structure of one or more of the other slotless phase windings of the stator, and wherein a first active segment of a second slotless phase winding is arranged between the first and second active segments of the first slotless phase winding. ### Claim 7 (depends on 6) The stator of claim 6, wherein an inactive segment of the second slotless phase winding is coupled to the first active segment of the second slotless phase winding; and wherein the inactive segment of the second slotless phase winding comprises a turn provided in the second inactive region, and wherein at least one of the conductive elements of the second slotless phase winding is twisted in the second inactive region. ### Claim 8 (depends on 7) The stator of claim 7, wherein the stator is arranged to enable the conductive elements of the turn of the first slotless phase winding to pass through the turn of the second slotless phase winding, and wherein the second active segment of the first slotless phase winding is arranged in the active region between first and second active segments of the second slotless phase winding. ### Claim 9 (depends on 7) The stator of claim 7, wherein the turn of the first slotless phase winding is arranged adjacent to the turn of the second slotless phase winding. ### Claim 10 (depends on 7) The stator of claim 7, wherein the first slotless phase winding is provided with the same twist as the second slotless phase winding. ### Claim 11 (depends on 4) The stator of claim 4, wherein a first active segment of a third slotless phase winding is provided in the active region between the first and second active segments of the first slotless phase winding. ### Claim 12 (depends on 1) The stator of claim 1, wherein the inactive segment of the serpentine structure of the slotless phase winding is a first inactive segment, and wherein the serpentine structure of the slotless phase winding further comprises a second inactive segment and a third active segment; and wherein the second inactive segment couples the second active segment to the third active segment, and wherein the second inactive segment comprises a turn provided in the first inactive region, wherein at least one of the conductive elements is twisted in the first inactive region, and wherein the twist in the first inactive region comprises a half twist, and the twist in the second inactive region also comprises a half twist. ### Claim 13 (depends on 1) The stator of claim 1, wherein the conductive filaments of the slotless phase winding are packaged into a fiber bundle, and wherein the fiber bundle has an orthogonal or hexagonal cross-sectional shape. ### Claim 14 (depends on 1) The stator of claim 1, wherein the conductor of each conductive element is rectangular, circular or hexagonal cross-sectional shape. ### Claim 15 (depends on 1) The stator of claim 1, wherein the stator is arranged to provide a radial air gap between the stator and the rotor; and wherein the active segments of the slotless phase winding extend in an axial direction parallel to a rotational axis of the rotor. ### Claim 16 (depends on 1) The stator of claim 1, wherein the stator is arranged to provide an axial air gap between the stator and the rotor; and wherein the active segments of slotless phase winding extend in a radial direction orthogonal to the rotational axis of the rotor. ### Claim 17 (depends on 1) The stator of claim 1, wherein at least one of: the stator is for interacting with magnets carried by a rotor of an electric motor, and wherein the stator is configured to apply current to the slotless phase winding to drive rotation of the rotor of the electric motor; and the stator is for interacting with magnets carried by a rotor of a generator, and wherein the stator is configured to harness energy from a resulting current generated in the slotless phase winding in response to rotation of the magnets of the rotor of the generator. ### Claim 18 (depends on 1) An electric machine comprising: the stator of claim 1; and a rotor carrying a plurality of magnets; wherein the electric machine is arranged so that the magnets carried by the rotor are aligned with the active region of the stator. ### Claim 19 (depends on 18) The electric machine of claim 18, wherein a distance of an air gap between the magnets of the rotor and the active region of the stator is smaller than a cross-sectional depth of the plurality of conductive elements of the slotless phase winding.