Rotating electric machine
A rotating electric machine includes a field system and an armature. The field system includes a magnet section having a plurality of magnetic poles whose polarities alternate in a circumferential direction. The armature includes a multi-phase armature coil. Either of the field system and the armature is configured as a rotor. The magnet section is configured to have an easy axis of magnetization oriented such that the closer the position to a d-axis in the circumferential direction, the more the direction of the easy axis of magnetization becomes parallel to the d-axis.
1. A rotating electric machine comprising:
a field system including a magnet section having a plurality of magnetic poles whose polarities alternate in a circumferential direction; and
an armature including a multi-phase armature coil,
wherein
either of the field system and the armature is configured as a rotor,
the magnet section includes first magnets that each correspond to one of the magnetic poles of the magnet section and are arranged at predetermined intervals in the circumferential direction, and the magnet section also includes second magnets each of which is arranged between one circumferentially-adjacent pair of the first magnets to extend across a q-axis,
each of the first magnets is oriented to form a magnet magnetic path parallel to a d-axis,
surfaces of the second magnets facing the first magnets constitute magnetic flux acting surfaces through which magnetic flux flows into or out of the second magnets,
each of the second magnets is oriented to form, at the q-axis, a magnet magnetic path deviated from a direction perpendicular to the q-axis,
0<θa≤2π/S, where S is a number of phases of the armature coil and θa is a main magnetic pole angle which is defined, for each of the first magnets, as an angle between (i) a straight line extending through one of two q-axis-side ends of the first magnet in the circumferential direction and an axis of the rotor and (ii) a straight line extending through the other of the two q-axis-side ends of the first magnet in the circumferential direction and the axis of the rotor, and
either (i) 2π/5<θa≤2π/3, (ii) θa=2π/3, or (iii) θa=2π/5.
2. The rotating electric machine as set forth in claim 1 , wherein each of the second magnets is oriented to form the magnet magnetic path that is convex toward an opposite side to the armature.
3. The rotating electric machine as set forth in claim 1 , wherein the armature coil has electrical conductor sections opposed to the field system and arranged at predetermined intervals in the circumferential direction,
in the armature, there are provided inter-conductor members between the electrical conductor sections in the circumferential direction or no inter-conductor members are provided between the electrical conductor sections in the circumferential direction, and
the inter-conductor members are formed of a magnetic material satisfying the following relationship or formed of a non-magnetic material,
Wt×Bs≤Wm×Br
where Wt is a circumferential width of the inter-conductor members in each magnetic pole, Bs is a saturation flux density of the inter-conductor members, Wm is a circumferential width of the magnet section in each magnetic pole and Br is a residual flux density of the magnet section.
4. The rotating electric machine as set forth in claim 3 , wherein each of the inter-conductor members is constituted of an arc-shaped portion that radially extends from a core of the armature, the arc-shaped portion having its distal end radially protruding from the electrical conductor sections toward the field system side and arc-shaped so as to be convex on the field system side.
5. The rotating electric machine as set forth in claim 1 , wherein the armature coil has electrical conductor sections opposed to the field system and arranged at predetermined intervals in the circumferential direction, and
a radial thickness of the electrical conductor sections is smaller than a circumferential width of the electrical conductor sections per phase in each magnetic pole.
6. The rotating electric machine as set forth in claim 1 , wherein the first and second magnets have an intrinsic coercive force higher than or equal to 400 [kA/m] and a residual flux density higher than or equal to 1.0[T].
7. A rotating electric machine comprising:
a field system including a magnet section having a plurality of magnetic poles whose polarities alternate in a circumferential direction; and
an armature including a multi-phase armature coil,
wherein
either of the field system and the armature is configured as a rotor,
the magnet section includes first magnets that each correspond to one of the magnetic poles of the magnet section and are arranged at predetermined intervals in the circumferential direction, and the magnet section also includes second magnets each of which is arranged between one circumferentially-adjacent pair of the first magnets to extend across a q-axis,
each of the first magnets is oriented to form a magnet magnetic path parallel to a d-axis,
surfaces of the second magnets facing the first magnets constitute magnetic flux acting surfaces through which magnetic flux flows into or out of the second magnets,
each of the second magnets is oriented to form, at the q-axis, a magnet magnetic path deviated from a direction perpendicular to the q-axis, and
either (i) 2π/3<θa≤4π/5, (ii) θa=4π/5, or (iii) 4π/5<θa<π, where θa is a main magnetic pole angle which is defined, for each of the first magnets, as an angle between (i) a straight line extending through one of two q-axis-side ends of the first magnet in the circumferential direction and an axis of the rotor and (ii) a straight line extending through the other of the two q-axis-side ends of the first magnet in the circumferential direction and the axis of the rotor.
8. The rotating electric machine as set forth in claim 7 , wherein the armature coil has electrical conductor sections opposed to the field system and arranged at predetermined intervals in the circumferential direction,
in the armature, there are provided inter-conductor members between the electrical conductor sections in the circumferential direction or no inter-conductor members are provided between the electrical conductor sections in the circumferential direction, and
the inter-conductor members are formed of a magnetic material satisfying the following relationship or formed of a non-magnetic material,
Wt×Bs≤Wm×Br
where Wt is a circumferential width of the inter-conductor members in each magnetic pole, Bs is a saturation flux density of the inter-conductor members, Wm is a circumferential width of the magnet section in each magnetic pole and Br is a residual flux density of the magnet section.
9. The rotating electric machine as set forth in claim 8 , wherein each of the inter-conductor members is constituted of an arc-shaped portion that radially extends from a core of the armature, the arc-shaped portion having its distal end radially protruding from the electrical conductor sections toward the field system side and arc-shaped so as to be convex on the field system side.
10. The rotating electric machine as set forth in claim 7 , wherein each of the second magnets is oriented to form the magnet magnetic path that is convex toward an opposite side to the armature.
11. The rotating electric machine as set forth in claim 7 , wherein the armature coil has electrical conductor sections opposed to the field system and arranged at predetermined intervals in the circumferential direction, and
a radial thickness of the electrical conductor sections is smaller than a circumferential width of the electrical conductor sections per phase in each magnetic pole.
12. The rotating electric machine as set forth in claim 7 , wherein the first and second magnets have an intrinsic coercive force higher than or equal to 400 [kA/m] and a residual flux density higher than or equal to 1.0[T].