Printed circuit board stator axial field rotary energy device with ferromagnetic yoke and cooling plate

1. An axial field rotary energy device, comprising:

a housing;

a rotor coupled to the housing, the rotor comprising an axis of rotation and a rotor disk comprising a magnet;

a cooling plate coaxial with the rotor and coupled to the housing, the cooling plate comprising a continuous sealed channel connected to an inlet and an outlet and configured to convey a liquid coolant;

a stator coaxial with the rotor and comprising a printed circuit board (PCB) having a plurality of conductive layers laminated together with layers of an insulating material, each conductive layer comprises a plurality of coils that can carry electrical current when connected to an external voltage source, and the stator is mechanically coupled to the housing, so the stator reacts to torque produced by the device; and

a ferromagnetic yoke coaxial with the rotor and the stator, the ferromagnetic yoke is mechanically and thermally coupled to the stator and to the cooling plate to provide a path for magnetic flux produced by the magnet and a path to conduct heat generated by the stator from the stator to the cooling plate.

2. The device of claim 1 , wherein the ferromagnetic yoke comprises a radial width W that is in a range of 90% to 110% of a radial length L of the magnet.

3. The device of claim 2 , wherein the ferromagnetic yoke comprises a low loss, soft ferromagnetic material.

4. The device of claim 3 , wherein the ferromagnetic yoke comprises a single annular ring of soft ferrite.

5. The device of claim 4 , wherein the soft ferrite comprises a Mn—Zn or Ni—Zn compound.

6. The device of claim 3 , wherein the ferromagnetic yoke comprises segments of soft ferrite.

7. The device of claim 6 , wherein the soft ferrite material comprises a Mn—Zn or Ni—Zn compound.

8. The device of claim 3 , wherein the ferromagnetic yoke is laminated and comprises a wound strip of low loss, high permeability, soft ferromagnetic alloy.

9. The device of claim 8 , wherein the ferromagnetic yoke comprises a relative permeability of 5,000 or more.

10. The device of claim 1 , wherein the rotor disk carries magnets on both sides, the device comprises two stators coaxial with the rotor and facing the rotor, and each stator is mechanically and thermally coupled to a respective ferromagnetic yoke and each yoke is coupled thermally and mechanically to a respective cooling plate.

11. The device of claim 10 , wherein the ferromagnetic yoke comprises a radial width W that is in a range of 90% to 110% of a radial length L of the magnet.

12. The device of claim 11 , wherein the ferromagnetic yoke comprises a low loss, soft ferromagnetic material.

13. The device of claim 12 , wherein the ferromagnetic yoke comprises a single annular ring of soft ferrite.

14. The device of claim 13 , wherein the soft ferrite comprises a Mn—Zn or Ni—Zn compound.

15. The device of claim 12 , wherein the ferromagnetic yoke comprises segments of soft ferrite.

16. The device of claim 15 , wherein the soft ferrite material comprises a Mn—Zn or Ni—Zn compound.

17. The device of claim 12 , wherein the ferromagnetic yoke is laminated and comprises a wound strip of low loss, high permeability, soft ferromagnetic alloy.

18. The device of claim 17 , wherein the ferromagnetic yoke comprises a relative permeability of 5,000 or more.

19. The device of claim 10 , wherein each conductive layer is etched.

20. The device of claim 1 , wherein there is only one air gap for the stator in the device.