Eddy current repulsion motor

Patent metadata

Field	Value
Publication number	US-10630128-B2
Application number	US-201514933333-A
Country	US
Kind code	B2
Filing date	Nov 5, 2015
Priority date	Nov 5, 2015
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

Abstract

A method and apparatus for controlling an electric motor. A flow of an alternating current through stator coils in the electric motor is controlled based on a position of a rotor in the electric motor such that a repulsive force between a rotor and a stator coil in the stator coils occurs when the alternating current flows through the stator coil.

First claim

The invention claimed is:

1. An apparatus comprising:
a rotor comprising an electrically conductive material, wherein the rotor is rotatable about an axis;
stator coils positioned adjacent to the rotor such that an eddy current is generated in the rotor when an alternating current flows through the stator coils; and
a current control system that controls a flow of the alternating current through the stator coils based on a position of the rotor, wherein a stator coil in the stator coils generates an alternating magnetic field when the alternating current flows through the stator coil causing the eddy current in the rotor such that a repulsive force between the stator coil and the rotor rotates the rotor about the axis.

2. The apparatus of claim 1 , wherein the current control system sends the alternating current through the stator coil when the position of the rotor is such that an end of the rotor is adjacent to the stator coil.

3. The apparatus of claim 1 , wherein the electrically conductive material is selected from at least one of a conductive ferromagnetic material or a conductive non-ferromagnetic material.

4. The apparatus of claim 3 , wherein the conductive ferromagnetic material is selected from at least one of iron, iron oxide, nickel, or samarium cobalt.

5. The apparatus of claim 3 , wherein the conductive non-ferromagnetic material is selected from at least one of aluminum, copper, gold, intercalated graphene, lead, silver, tin, titanium, or zinc.

6. The apparatus of claim 1 , wherein each of the stator coils has a different resonant frequency from other stator coils in the stator coils and further comprising:
a power source configured to transmit power to the stator coils by a wireless magnetic coupling to the stator coils, wherein the power transmitted results in the alternating current flowing through the stator coils.

7. The apparatus of claim 1 , wherein the current control system comprises:
switches connected to the stator coils, wherein a switch in the switches sends the alternating current through the stator coil when the switch is in a closed position; and
a controller that controls the switches in controlling the flow of the alternating current through the stator coils based on the position of the rotor, wherein the stator coil in the stator coils generates the alternating magnetic field when the alternating current flows through the stator coil causing the eddy current in the rotor such that the repulsive force between the stator coil and the rotor causes the rotor to rotate about the axis.

8. The apparatus of claim 7 , wherein the controller is configured to switch the alternating current through the stator coil in the stator coils in which the rotor has the position in which an end of the rotor is aligned with the stator coil.

9. The apparatus of claim 7 further comprising:
a rotary encoder that indicates the position of the rotor.

10. The apparatus of claim 7 , wherein the controller is comprised of at least one of a solid state circuit, silicon controlled rectifier, or a triode for alternating current circuit.

11. The apparatus of claim 7 further comprising:
a group of position sensing coils that react with the eddy current in the rotor based on the position of the rotor, wherein the controller identifies the position of the rotor using the group of position sensing coils.

12. The apparatus of claim 1 , wherein first ends of the stator coils are connected to an alternating current power supply and the current control system comprises:
electrical brushes connected to second ends of the stator coils; and
electrical contacts positioned about the axis wherein the electrical contacts are connected to a power source and are arranged in pattern such that the electrical brushes contact the electrical contacts at different positions of rotor when electrical contacts rotate about the axis controlling the flow of the alternating current through the stator coils.

13. The apparatus of claim 1 , wherein the rotor comprises:
a core comprising a ferromagnetic material; and
a layer on the core, wherein the layer comprises a conductive non-ferromagnetic material,
wherein the current control system controls a direct current and the alternating current through the stator coils to selectively attract and repel the rotor.

14. The apparatus of claim 13 further comprising:
a capacitor connected in parallel to the stator coils and a direct current power supply, wherein the capacitor generates the alternating current from charges stored in the capacitor.

15. The apparatus of claim 1 , wherein the stator coils are positioned adjacent to the rotor such that the repulsive force is sufficient to rotate the rotor from any stationary position of the rotor.

16. The apparatus of claim 1 , wherein a first frequency of the alternating current is independent of a second frequency of a rotation of the rotor.

17. The apparatus of claim 16 , wherein the first frequency of the alternating current is equal to or greater than about 10 kHz.

18. The apparatus of claim 1 , wherein the eddy current causes the repulsive force when interacting with the alternating magnetic field causes in which a tangential force in the repulsive force causes a torque that rotates the rotor about the axis.

19. A dual frequency electric motor comprising:
a rotor rotatable about an axis, wherein the rotor comprises a core formed from a ferromagnetic material and a layer encompassing the core, wherein the layer comprises a conductive non-ferromagnetic material;
stator coils that are connected to an alternating current power supply and a direct current power supply; and
a current control system that controls a flow of an alternating current and a direct current through the stator coils based on a position of the rotor, wherein a stator coil in the stator coils generates an alternating magnetic field when the alternating current flows through the stator coil causing a repulsive force between the stator coil and the rotor and generates a unidirectional magnetic field when a direct current flows through the stator coil causing an attractive force between the stator coil and the rotor such that the rotor rotates about the axis.

20. The dual frequency electric motor of claim 19 further comprising:
capacitors connected in parallel to the stator coils and the direct current power supply, wherein the capacitors are the alternating current power supply when the direct current power supply is disconnected from the stator coils and wherein each stator coil in the stator coils has a set of capacitors that is connected in parallel or series.

21. The dual frequency electric motor of claim 19 , wherein conductive ferromagnetic metal is selected from at least one of iron, iron oxide, nickel, or samarium cobalt.

22. The dual frequency electric motor of claim 19 , wherein conductive non-ferromagnetic material is selected from at least one of aluminum, copper, gold, intercalated graphene, lead, nickel, silver, tin, titanium, or zinc.

23. A method for controlling an electric motor, the method comprising:
controlling a flow of an alternating current through stator coils in the electric motor based on a position of a rotor in the electric motor such that a repulsive force between the rotor and a stator coil in the stator coils occurs when the alternating current flows through the stator coil.

24. The method of claim 23 further comprising:
identifying the position of the r

Assignees

• Boeing Co

Inventors

• Tillotson Brian Jay
• Zeng Peng

Classifications

• H02K11/20

  for measuring, monitoring, testing, protecting or switching (rectifiers H02K11/04; power electronics H02K11/33) · CPC title

• H02P6/15

  Controlling commutation time · CPC title

• H02P29/00

  Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors (arrangements for starting electric motors H02P1/00; arrangements for stopping or slowing electric motors H02P3/00; control of motors that can be connected to two or more different electric power supplies H02P4/00; regulating or controlling the speed or torque of two or more electric motors H02P5/00; vector control H02P21/00) · CPC title

• H02K1/02

  characterised by the magnetic material · CPC title

• H02K19/06

  Motors having windings on the stator and a variable-reluctance soft-iron rotor without windings, e.g. inductor motors · CPC title