Magnetic bearing using displacement winding techniques

• US 7,235,906 B2
• Filed: 05/10/2005
• Issued: 06/26/2007
• Est. Priority Date: 05/10/2004
• Status: Expired due to Fees

• Current Assignee: Airex Co., Ltd.
• Original Assignee: Airex Co., Ltd.
• Inventors: Carroll, David, Salwen, John
• Primary Examiner(s): Mullins; Burton S.
• Assistant Examiner(s): PRESTON, ERIK D
• Application Number:
  US11/125,917
• Publication Number:
  US 20050264119A1
• Time in Patent Office: 777 Days
• Field of Search: 310/90.5, 310/184, 310/207
• US Class Current: 310/90.5
• CPC Class Codes: F16C 32/044 Active magnetic bearings
• CPC Class Codes: H02K 21/12 with stationary armatures and rotating magnets
• CPC Class Codes: H02K 2201/18 Machines moving with multiple degrees of freedom
• CPC Class Codes: H02K 29/03 with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems
• CPC Class Codes: H02K 41/03 Synchronous motors; Motors moving step by step; Reluctance motors H02K41/035 takes precedence
• CPC Class Codes: H02K 7/09 with magnetic bearings

Abstract

The present invention provides a linear, rotary spherical motor with an integrated magnetic bearing. The motor can be a toothless permanent magnet, BLDC design composed of a permanent magnet rotor and a Zigzag stator winding containing at least two-phase windings, where each phase is constructed of at least two circuits. Other exemplary embodiments include a trapezoidal winding configuration. The individual circuits of a phase are displaced away from each other along a line that is at right angles to the direction of the alternating polarity magnet array. The circuits forming a phase share the same “slot”, and each circuit resembles a complete phase winding, however each circuit contains a proportion of the total number of turns of the phase. Controllable axial bearing force is developed through the differential balance of the currents in the circuits, while required motor torque is generated by the sum of the individual currents in a given phase. The relative motion in the rotor can produce back EMF which can provide positional information; A) in the direction parallel to the magnet array via the sum of the voltages in a phase; B) in the direction normal to the magnet array via the difference in circuit voltages.

Claims

1. A linear, rotary or spherical motor bearing system comprising:

a stator winding comprising a plurality of phases, each said phase comprising a plurality of circuits, wherein each circuit provides a complete phase winding, and wherein each circuit is displaced from one another, and wherein each phase is capable of imparting a first force on a rotor in a first direction based on a differential current in said plurality of circuits of said phase and capable of imparting a second force on said rotor in a second direction based on a sum of said current through said plurality of circuits of said phase.

2. A motor bearing system as claimed in claim 1, wherein said circuits are displaced from one another in a direction other than the principal flux rotation vector direction.

3. A motor bearing system as claimed in claim 1, wherein the winding geometry of each circuit comprises a displaced Zig-Zag geometry.

4. A motor bearing system as claimed in claim 1, wherein the winding geometry of each circuit comprises a mirrored trapezoid geometry.

5. A motor bearing system as claimed in claim 1, wherein the phase or amplitude differences between the currents in each said circuit creates controllable and directed forces along the plane of the stator winding.

6. A linear, rotary or spherical motor with an integral electromagnetic bearing comprising a rotor assembly comprising a plurality of permanent magnets and a stator assembly, said stator assembly includes windings comprising two or more phases, each phase comprising of two or more circuits, wherein each circuit provides a complete phase winding, and wherein each said circuit is displaced with respect to one another, and wherein each phase is capable of imparting a first force on said rotor in a first direction based on a differential current in said plurality of circuits of said phase and capable of imparting a second force on said rotor in a second direction based on a sum of said current through said plurality of circuits of said phase.

7. A motor as claimed in claim 6, wherein said circuits are displaced from one another in a direction other than the principal flux rotation vector direction.

8. A motor as claimed in claim 6, wherein the winding geometry of each circuit comprises a displaced Zig-Zag geometry.

9. A motor as claimed in claim 6, wherein the winding geometry of each circuit comprises a mirrored trapezoid geometry.

10. A motor as claimed in claim 6, wherein the phase or amplitude differences between the currents in each said circuit creates controllable and directed forces along the plane of the stator winding.