Stator cooling channels with internal features

1. An electric machine comprising:

a stator core defining a plurality of core slots in a surface thereof;

a winding positioned at least partially in one of the plurality of core slots, the winding including a tube defining a channel through at least a portion thereof and one or more wires disposed along the tube opposite the channel, wherein the channel includes a first end portion and a second, opposing end portion;

one or more internal surface features within the channel, the one or more internal structures extending from a bottom portion of the channel to a top portion of the channel;

a cooling system including a supply line operably coupled with the first end portion and a return line operably coupled with the second end portion, the cooling system configured to move a cooling fluid through the channel; and

an insulative break disposed along each of the supply lines and return lines to prevent current flow from the winding to the cooling system.

2. The electric machine of claim 1 , further comprising:

a controller operably coupled to the cooling system and configured to operate a pump of the cooling system.

3. The electric machine of claim 1 , wherein the one or more wires are configured as a Litz-wire having a plurality of strands.

4. The electric machine of claim 3 , wherein each of the plurality of strands is individually coated with an insulating layer.

5. The electric machine of claim 1 , wherein the one or more wires includes a plurality of wires positioned about an outer surface of the tube, and wherein each of the plurality of wires includes an outer jacket.

6. The electric machine of claim 5 , further comprising:

a strap disposed around each of the plurality of wires, wherein the strap extends in a generally perpendicular direction to each of the plurality of wires.

7. The electric machine of claim 1 , wherein the channel includes a first channel and a second channel separate from the first channel.

8. The electric machine of claim 7 , wherein the one or more wires includes a first set of wires positioned between the first and second channels and a second set of wires positioned about the first channel, the second channel, and the first set of wires.

9. The electric machine of claim 8 , wherein the first set of wires is of a first gauge and the second set of wires is of a second gauge, the first gauge different from the second gauge.

10. The electric machine of claim 1 , wherein the tube is formed from a first material and the one or more wires include a second material, and wherein the first material is common with the second material.

11. The electric machine of claim 1 , wherein the tube is formed from a first material and the one or more wires include a second material, and wherein the first material is different from the second material.

12. The electric machine of claim 1 , wherein the channel has a generally square cross section and the one or more internal features has a varied geometry from the channel.

13. A method of manufacturing an electric machine, the method comprising:

forming a tube defining a channel through at least a portion thereof through an additive manufacturing process, the channel defining one or more internal features integrally formed with the channel;

positioning one or more wires about a surface of the tube to form a winding, wherein the one or more wires are separated from the channel by the tube;

operably coupling the winding to one of a stator core or a rotor of the electric machine; and

fluidly coupling a cooling system to the channel to provide a fluid through the channel, wherein a flow of the fluid is altered from a laminar flow to a turbulent flow by the internal features, the cooling system including a supply line operably coupled with a first end portion of the channel and a return line operably coupled with a second end portion of the channel.

14. The method of claim 13 , wherein the one or more wires are each configured as a Litz-wire having a plurality of strands.

15. The method of claim 13 , wherein fluidly coupling the cooling system to the channel includes coupling the supply line to one end portion of the winding and the return line to a second end portion of the winding.

16. The method of claim 15 , wherein fluidly coupling the cooling system to the channel further includes fluidly coupling a pump and a heat exchanger in series between the supply line and the return line.

17. A winding assembly for an electric machine comprising:

a tube defining a channel through at least a portion thereof, the tube configured to be operably coupled with a stator or a rotor of the electric machine, wherein the channel includes a first end portion, an opposing, second end portion, and an enclosed body between the first end portion and the second end portion;

a plurality of internal surface features positioned within the channel, wherein a concentration of the plurality of internal surface features is varied along the channel;

one or more wires, the one or more wires positioned along the tube opposite the channel; and

a cooling system including a supply line operably coupled with the first end portion and a return line operably coupled with the second end portion, the cooling system configured to move a cooling fluid through the channel.

18. The electric machine of claim 17 , wherein the one or more wires configured as Litz-wires and a cooling system is operably coupled with the channel and configured to move a cooling fluid through the channel.

19. The electric machine of claim 17 , wherein the one or more wires includes a first set of wires and a second set of wires, and wherein the tube includes a first tube and a second tube.

20. The electric machine of claim 19 , wherein the second set of wires is positioned between the first and second tubes and the first set of wires is positioned around the first tube, the second tube, and the second set of wires.