Optimized Electric Machine for Smart Actuators

• US 20100244610A1
• Filed: 03/24/2009
• Published: 09/30/2010
• Est. Priority Date: 03/24/2009
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Hao, Lei, Namuduri, Chandra S., Murty, Balarama V.
• Granted Patent: US 8,816,556 B2
• Time in Patent Office: Days
• US Class Current: 310/179
• CPC Class Codes: H02K 1/27 Rotor cores with permanent magnets
• CPC Class Codes: H02K 1/278 Surface mounted magnets; Inset magnets
• CPC Class Codes: H02K 1/30 using intermediate parts, e.g. spiders
• CPC Class Codes: H02K 21/12 with stationary armatures and rotating magnets
• CPC Class Codes: H02K 21/16 having annular armature cores with salient poles with homopolar co-operation H02K21/20
• CPC Class Codes: H02K 29/03 with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems
• CPC Class Codes: H02K 7/08 Structural association with bearings
• CPC Class Codes: H02K 7/083 radially supporting the rotary shaft at both ends of the rotor H02K7/086, H02K7/09 take precedence
• CPC Class Codes: H02K 7/088 radially supporting the rotor directly

Abstract

A single stator electric machine includes a plurality of magnets for generating a first magnetic field. Each respective magnet represents a respective rotor pole. A magnet holder retains the plurality of magnets. A stator is disposed radially outward from the plurality of magnets for generating a second magnetic field. The stator includes a plurality of stator poles separated by slots with each of the stator poles having a concentrated winding with a respective number of turns formed around each respective stator pole. Each respective concentrated winding within the stator comprises non-overlapping phases which increase an active length of the windings of the stator and reduce an overhang of each respective winding with respect to each stator pole for improving torque efficiency. A number of rotor poles is at least eight and the number of rotor poles and a number of stator slots have a least common multiple of at least 36.

Claims

1. A single stator electric machine comprising:

a plurality of magnets for generating a first magnetic field, each respective magnet represents a respective rotor pole;

a magnet holder for retaining the plurality of magnets, the magnet holder having a circular configuration with the plurality of magnets being positioned around the circular configuration of the magnet holder; and

a stator disposed radially outward from the plurality of magnets for generating a second magnetic field, the magnet and the stator having a first air gap formed therebetween, the stator including a plurality of stator poles separated by slots with each of the stator poles having a concentrated winding with a respective number of turns formed around each respective stator pole, each respective concentrated winding within the stator comprising non-overlapping phases, the concentrated windings increase an active length of the windings of the stator and reduce an overhang of each respective winding with respect to each stator pole for improving torque density and machine efficiency;

wherein the number of rotor poles is at least eight, and wherein the number of rotor poles and a number of stator slots have a least common multiple of at least 36.

2. The electric machine of claim 1 wherein the magnet holder and the plurality of magnets form a coreless rotor.

3. The electric machine of claim 2 wherein the magnet holder is made of a magnetic material for generating a flux loop in cooperation with the stator and plurality of magnets, and wherein the magnet holder is rotatable for generating a torque.

4. The electric machine of claim 2 further comprising a stationary magnetic inner core disposed radially inward of the magnet holder, wherein a second air gap is formed between the magnetic inner core and the magnet holder, wherein the stationary magnetic inner core generates a flux loop in cooperation with the stator and plurality of magnets, and wherein the magnet holder is made of a non-magnetic material.

5. The electric machine of claim 1 wherein the concentrated windings include a winding factor of greater than 0.7.

6. The electric machine of claim 1 wherein a number of stator slots is an even integer.

7. The electric machine of claim 1 further comprising a shaft coupled to the magnet holder and is co-axial to the magnet holder, the shaft being configured for coupling to a driven component, wherein an electromagnetic force generated by the magnet and the stator is converted into a mechanical torque, the mechanical torque being applied via the magnet holder and shaft to the driven component.

8. The electric machine of claim 7 wherein the magnet holder is adapted to be coupled to an actuator for an active suspension system.

9. The electric machine of claim 7 wherein the magnet holder is adapted to be coupled to an actuator for a semi active suspension system.

10. The electric machine of claim 7 wherein the magnet holder is adapted to be coupled to an actuator for an electric power steering system.

11. The electric machine of claim 7 wherein the magnet holder is adapted to be coupled to an actuator for an electromechanical braking system.

12. The electric machine of claim 7 can be used as traction machine for a hybrid propulsion system.

13. The electric machine of claim 7 can be used as traction machine for a fuel cell propulsion system.

14. The electric machine of claim 7 can be used as traction machine for an electrical propulsion system.