Rotary electric machine and electric power steering device using rotary electric machine

Patent metadata

Field	Value
Publication number	US-9755470-B2
Application number	US-201515311068-A
Country	US
Kind code	B2
Filing date	Aug 4, 2015
Priority date	Oct 30, 2014
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

In a rotary electric machine, when armature coil bodies of respective phases in which first and second armature windings, are both wound around 6 k×n teeth are set as Ua, Va, and Wa, armature coil bodies of respective phases in which only the first and armature winding is wound around 6 m×n teeth are set as Ub, Vb, and Wb, and armature coil bodies of respective phases in which only the second armature winding is wound around 6 m×n teeth are set as Uc, Vc, and Wc, Ua, Va, Wa, Ub, Vb, Wb, Uc, Vc, and Wc are respectively arranged so as to exhibit 2 n-fold rotational symmetry about an axial center of a rotor.

First claim

The invention claimed is:

1. A rotary electric machine comprising:
a rotor having a rotor core and a plurality of field poles provided in the rotor core; and
a stator having a stator core that includes 6 (2 m+k)×n (where k, n, and m are integers no smaller than 1) teeth and a plurality of armature coil bodies in which at least one of a first armature winding and a second armature winding is wound around each of the plurality of teeth,
wherein a three-phase current is supplied to the first armature winding from a first inverter,
a three-phase current is supplied to the second armature winding from a second inverter,
each of the plurality of armature coil bodies is an armature coil body of one of three phases,
2 k×n armature coil bodies of each of the three phases, in which the first armature winding and the second armature winding are both wound around 6 k×n of the teeth, form 6 k×n armature coil bodies of the plurality of armature coil bodies, and these armature coil bodies of each of the three phases are set respectively as Ua, Va, and Wa,
2 m×n armature coil bodies of each of the three phases, in which only the first armature winding is wound around 6 m×n of the teeth, form further 6 m×n armature coil bodies of the plurality of armature coil bodies, and these armature coil bodies of each of the three phases are set respectively as Ub, Vb, and Wb,
2 m×n armature coil bodies of each of the three phases, in which only the second armature winding is wound around 6 m×n of the teeth, form the remaining 6 m×n armature coil bodies of the plurality of armature coil bodies, and these armature coil bodies of each of the three phases are set respectively as Uc, Vc, and Wc, and
Ua, Va, Wa, Ub, Vb, Wb, Uc, Vc, and Wc are respectively arranged so as to exhibit 2 n-fold rotational symmetry about an axial center of the rotor, and
respective electrical angle phases of Ua, Va, and Wa take a value no smaller than an (m+1) th smallest value and no larger than an (m+k) th smallest value among the (2 m+k) armature coil bodies of the same phase within a minimum unit of the rotational symmetry.

2. The rotary electric machine according to claim 1 , wherein m=1 and k=1, and
the respective electrical angle phases of Ua, Va, and Wa take a second smallest value among the three armature coil bodies of the same phase within the minimum unit of the rotational symmetry.

3. The rotary electric machine according to claim 1 , wherein a phase of the current supplied to the second armature winding from the second inverter is advanced by a current phase difference θ relative to a phase of the current supplied to the first armature winding from the first inverter,
Ub, Vb, and Wb are the armature coil bodies having the most advanced electrical angle phases among the armature coil bodies of the same phase within the minimum unit of the rotational symmetry, and
Uc, Vc, and Wc are the armature coil bodies having the most retarded electrical angle phases among the armature coil bodies of the same phase within the minimum unit of the rotational symmetry.

4. The rotary electric machine according to claim 3 , wherein the rotor includes (18±4)×n (where n is an integer no smaller than 1) field poles.

5. The rotary electric machine according to claim 3 , wherein the rotor includes (18±2)×n (where n is an integer no smaller than 1) field poles.

6. The rotary electric machine according to claim 4 , wherein respective numbers of turns of Ua, Va, Wa, Ub, Vb, Wb, Uc, Vc, and Wc are all equal, and
the current phase difference θ satisfies a relationship of
0°<θ≦53°.

7. The rotary electric machine according to claim 6 , wherein the current phase difference θ satisfies a relationship of
13°<θ≦41°.

8. The rotary electric machine according to claim 4 , wherein respective numbers of turns of Ua, Va, Wa, Ub, Vb, Wb, Uc, Vc, and Wc are all equal, and
the current phase difference θ satisfies a relationship of
22°<θ≦60°.

9. The rotary electric machine according to claim 8 , wherein the current phase difference θ satisfies a relationship of
24°<θ≦60°.

10. The rotary electric machine according to claim 1 , wherein when respective numbers of turns of Ua, Va, and Wa are set at Nt1 and respective numbers of turns of Ub, Vb, Wb, Uc, Vc, and Wc are set at Nt2, a relationship of
Nt 1< Nt 2
is established.

11. The rotary electric machine according to claim 4 , wherein when respective numbers of turns of Ua, Va, and Wa are set at Nt1, respective numbers of turns of Ub, Vb, Wb, Uc, Vc, and Wc are set at Nt2, a turn ratio is set at t=Nt1/Nt2 (where t<1), and θa=−20t+73, the current phase difference θ satisfies a relationship of
0°<θ≦θ a°.

12. The rotary electric machine according to claim 1 , wherein a circumferential direction width of the teeth around which any of Ub, Vb, Wb, Uc, Vc, and Wc is wound is greater than the circumferential direction width of all of the teeth around which any of Ua, Va, and Wa is wound.

13. The rotary electric machine according to claim 1 , wherein a wire diameter of Ub, Vb, Wb, Uc, Vc, and Wc is greater than respective wire diameters of all of Ua, Va, and Wa.

14. The rotary electric machine according to claim 1 , wherein the rotor includes field poles formed by a plurality of permanent magnets embedded in the rotor core.

15. An electric power steering device equipped with the rotary electric machine according to claim 1 .

16. The rotary electric machine according to claim 5 , wherein respective numbers of turns of Ua, Va, Wa, Ub, Vb, Wb, Uc, Vc, and Wc are all equal, and
the current phase difference θ satisfies a relationship of
0°<0≦53°.

17. The rotary electric machine according to claim 5 , wherein when respective numbers of turns of Ua, Va, and Wa are set at Nt1, respective numbers of turns of Ub, Vb, Wb, Uc, Vc, and Wc are set at Nt2, a turn ratio is set at t=Nt1/Nt2 (where t<1), and θa=−20t+73, the current phase difference θ satisfies a relationship of
0°<θ≦θ a°.

Assignees

• Mitsubishi Electric Corp

Inventors

• HIROTANI Yu
• Nakano Masatsugu
• Ito Kazumasa
• Ueyama Hiroko

Classifications

• B62D5/04

  electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear · CPC title

• H02K3/28 Primary

  Layout of windings or of connections between windings (windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32) · CPC title

• H02K21/16

  having annular armature cores with salient poles (with homopolar co-operation H02K21/20) · CPC title

• H02P25/184

  wherein the motor speed is changed by switching from a delta to a star, e.g. wye, connection of its windings, or vice versa · CPC title

• H02P6/10

  Arrangements for controlling torque ripple, e.g. providing reduced torque ripple · CPC title