Axial Field Electric Motor and Method

• US 20090001831A1
• Filed: 06/26/2007
• Published: 01/01/2009
• Est. Priority Date: 06/26/2007
• Status: Abandoned Application

• Current Assignee: United States Of America Naval Undersea Warfare Center
• Original Assignee: United States Of America Naval Undersea Warfare Center
• Inventors: Cho, Chahee P., Lee, Chong O.
• Application Number:
  US11/768,258
• Publication Number:
  US 20090001831A1
• Time in Patent Office: Days
• US Class Current: 310/112
• CPC Class Codes: H02K 21/16 having annular armature cores with salient poles with homopolar co-operation H02K21/20
• CPC Class Codes: H02K 21/24 with magnets axially facing the armatures, e.g. hub-type cycle dynamos
• CPC Class Codes: H02K 7/09 with magnetic bearings
• CPC Class Codes: Y10T 29/49012 Rotor

Abstract

A hybrid field, brushless, permanent magnet electric motor utilizing a rotor with two sets of permanent magnets oriented such that the flux produced by the two sets of magnets is perpendicular to each other. A plurality of axial flux permanent magnets are positioned radially interiorly of a plurality of radial flux permanent magnets. Axial stators interact with the axial flux permanent magnets. A radially positioned stator interacts with radial flux permanent magnets. In one configuration, an electronic feedback system is created that magnetically clamps and holds the hybrid rotor in its axially centrally aligned position, thereby reducing axial vibrations.

Claims

1. An electric motor comprising:

a rotor mounted for rotation;

a plurality of axial flux permanent magnets carried by said rotor, said plurality of axial flux permanent magnets oriented such that an associated magnetic flux produced thereby is at least substantially axially oriented and said plurality of axial flux permanent magnets positioned around said rotor with alternating orientations of flux direction such that a flux direction of adjacent magnets is at least substantially axially oriented but opposite in direction;

a plurality of radial flux permanent magnets carried by said rotor, said plurality of radial flux permanent magnets oriented such that an associated magnetic flux produced thereby is at least substantially radially oriented and said plurality of radial flux permanent magnets positioned around said rotor with alternating orientations of flux direction such that a flux direction of adjacent magnets is at least substantially radially oriented but opposite in direction;

a first axial stator and a second axial stator, said first axial stator and said second axial stator positioned on axially opposite sides of said plurality of axial flux permanent magnets, said first axial stator and said second axial stator comprising a plurality of axial stator windings oriented for interacting with said plurality of axial flux permanent magnets; and

a radial stator positioned radially around said rotor, said radial stator comprising a plurality of radial stator windings oriented for interacting with said plurality of radial flux permanent magnets.

2. The electric motor of claim 1, wherein at least a portion of said plurality of radial stator windings are oriented with respect to said plurality of radial flux permanent magnets to produce at least one axially directed force on said rotor.

3. The electric motor of claim 2, wherein at least a portion of said plurality of radial stator windings are oriented to produce a first axial force acting on said rotor and a second axial force acting on said rotor, said first axial force and said second axial forces being opposite in direction and acting to prevent axial vibration of said rotor.

4. The electric motor of claim 3, further comprising a first radial stator winding positioned adjacent a first axial side of said rotor and a second radial stator winding positioned adjacent a second axial side of said rotor, such that as said rotor moves axially away from said first radial stator winding then said first axial force decreases whereby said second axial force urges said rotor to move axially back toward said first radial stator winding thereby acting to centralize said rotor between said first radial stator winding and said second radial stator winding.

5. The electric motor of claim 1, wherein at least a portion of said plurality of radial stator windings are oriented in a direction transverse to an axis of rotation of said rotor.

6. The electric motor of claim 1, wherein at least a portion of said plurality of radial stator windings are oriented in a direction parallel to an axis of rotation of said rotor.

7. A method for making an electric motor comprising:

mounting a rotor in a motor housing for rotation therein;

mounting on the rotor a plurality of axial flux permanent magnets oriented such that an associated magnetic flux produced thereby is at least substantially axially oriented;

mounting on the rotor a plurality of radial flux permanent magnets oriented such that an associated magnetic flux produced thereby is at least substantially radially oriented and positioning the plurality of radial flux permanent magnets on the rotor radially outwardly from the plurality of axial flux permanent magnets;

mounting to the motor housing a first axial stator and a second axial stator on axially opposite sides of the plurality of axial flux permanent magnets and the providing the first axial stator and the second axial stator with a plurality of axial stator windings oriented for interacting with the plurality of axial flux permanent magnets; and

mounting to the motor housing a radial stator positioned radially around the rotor and providing the radial stator with a plurality of radial stator windings for interacting with the plurality of radial flux permanent magnets.

8. The method of claim 7, orienting at least a portion of the radial stator windings with respect to the plurality of radial flux permanent magnets to produce at least one axially directed force on the rotor.

9. The method of claim 7, orienting at least a portion of the plurality of radial stator windings to produce a first axial force acting on the rotor and an oppositely directed second axial force acting on the rotor to resist axial vibration of the rotor.

10. The method of claim 9, further comprising positioning a first radial stator winding adjacent a first axial side of the rotor and a second radial stator winding adjacent a second axial side of the rotor such that as the rotor moves axially away from the first radial stator winding, then the first axial force decreases whereby the second axial force urges the rotor to move axially back toward the first radial stator winding, thereby acting to centralize the rotor between said the radial stator winding and the second radial stator winding.

11. The method of claim 7, further comprising orienting at least a portion of the plurality of radial stator windings in a direction transverse to an axis of rotation of said rotor.

12. The method of claim 7, further comprising orienting at least a portion of the plurality of radial stator windings in a direction parallel to an axis of rotation of the rotor.