Synchronous reluctance motor
A synchronous reluctance motor includes a rotor having a rotor iron core and a stator having pole teeth. The rotor iron core defines multiple magnetic poles. A magnetic barrier area is defined between adjacent magnetic poles in a circumferential direction, and a conductor area is located at a radially outer side of the magnetic barrier area. The magnetic barrier area is provided with a hole arranged in multiple layers in a radial direction and defining a magnetic barrier. The conductor area is provided with multiple conductors arranged at substantially equal intervals in the circumferential direction and having substantially identical cross-sectional shapes as each other. The following relationship is satisfied: Nc={2×[Nt/(2×Np)−1]−1}×Np where Nt is a number of the pole teeth, Np is a number of the magnetic poles, and Nc is a number of the conductors.
1 . A synchronous reluctance motor, comprising a rotor and a stator, wherein
the rotor comprises a rotor iron core,
the stator has a plurality of pole teeth, provided at a radially outer side, opposite and spaced apart from the rotor iron core, and arranged at substantially equal intervals in a circumferential direction,
the rotor iron core defines a plurality of magnetic poles arranged in the circumferential direction,
a magnetic barrier area is defined between adjacent magnetic poles in the circumferential direction, and
a conductor area is located at the radially outer side of the magnetic barrier area,
the magnetic barrier area is provided with a hole arranged in a plurality of layers in a radial direction and defining a magnetic barrier, and
the conductor area is provided with conductors, wherein:
a plurality of the conductors are arranged at substantially equal intervals in the circumferential direction and have substantially identical cross-sectional shapes as each other; and
the following relationship is satisfied:
Nc
=
{
2
×
[
Nt
/
(
2
×
Np
)
-
1
]
-
1
}
×
Np
,
where Nt is a number of the pole teeth, Np is a number of the magnetic poles, and Nc is a number of the conductors,
wherein the hole of each of the layers is respectively provided with a magnet and respectively comprises a pair of divided holes divided by a bridge, which is a portion of the rotor iron core and located substantially on a q-axis, and
the magnet comprises divided magnets provided adjacent to the q-axis in each of the divided holes.
2 . The synchronous reluctance motor according to claim 1 , wherein
when viewed along an axial direction, the conductors have a strip shape extending in the radial direction, or
when viewed along the axial direction, two ends of the conductors in the radial direction are semicircular shapes, respectively, or
when viewed along the axial direction, intermediate portions between the two ends of the conductors in the radial direction have a tapered shape in which a circumferential width becomes narrower toward the inside in the radial direction.
3 . The synchronous reluctance motor according to claim 1 , wherein
the following relationship is satisfied:
Wt
≤
Dc
≤
1.5
Wt
,
where Dc is a distance between adjacent conductors in the circumferential direction, and Wt is a circumferential width of the pole teeth.
4 . The synchronous reluctance motor according to claim 1 , wherein
the rotor iron core has a circular hole centered on a rotation center of the rotor at a position radially inward of the magnetic barrier area, and
the following relationship is satisfied:
0.35
R
≤
Lc
≤
0.45
R
,
where Lc is a radial length of the conductors, and R is a radial distance between an outer circumferential surface of the rotor iron core and an inner circumferential surface of the circular hole.
5 . The synchronous reluctance motor according to claim 1 , wherein
the following relationship is satisfied:
Nb
<
Nt
/
(
4
Np
)
,
where Nb is a number of the layers.
6 . The synchronous reluctance motor according to claim 1 , wherein
when viewed along an axial direction, the hole of each of the layers respectively has a shape of arcs or straight lines.
7 . The synchronous reluctance motor according to claim 1 , wherein
circumferential widths of end portions in the circumferential direction of the each hole of each layer are smaller than a minimum circumferential width of an intermediate portion between both end portions in the radial direction of the conductor.
8 . The synchronous reluctance motor according to claim 1 , wherein
circumferential ends of the hole of each layer are respectively opposed to a radially inner end of one of the conductors.
9 . The synchronous reluctance motor according to claim 8 , wherein
the rotor iron core comprises iron core sheets laminated in an axial direction; and
the following relationship is satisfied:
D
≥
T
,
where D is a distance between ends of the hole of each of the layers in the circumferential direction and ends of the conductors at a radially inner side, and T is a thickness of the iron core sheets.
10 . The synchronous reluctance motor according to claim 1 , wherein
the following relationship is satisfied:
θ
≤
360
/
(
2
×
Ns
×
Np
)
,
where θ is an angle defined by the d-axis and a line connecting the point Pt and the rotation center of the rotor under the condition that Pt being an intersection point of a tangent line at a circumferential end portion of a radially inner edge of a radially outermost hole and the outer circumferential surface of the rotor iron core, and Ns is a number of the magnetic poles.
11 . The synchronous reluctance motor according to claim 1 , wherein
the following relationship is satisfied:
θ1
≥
(
3
×
360
)
/
Nt
,
a
nd
θ2
≥
θ1
where Wb is a circumferential width of the bridge, and Wo is an opening width of a groove between adjacent pole teeth in the circumferential direction, and Wt is a circumferential width of the pole teeth.
12 . The synchronous reluctance motor according to claim 1 , wherein
the following relationship is satisfied:
Wo
≤
Wb
≤
0.5
Wt
where θ1 is an angle defined by lines which connect the rotation center of the rotor and circumferential both ends of a radially inner edge of the magnet in a radially outermost hole respectively, θ2 is an angle defined by lines which connect the rotation center of the rotor and circumferential both ends of a radially inner edge of the magnet in a radially innermost hole respectively.
13 . A synchronous reluctance motor, comprising a rotor and a stator, wherein
the rotor comprises a rotor iron core,
the stator has a plurality of pole teeth, provided at a radially outer side, opposite and spaced apart from the rotor iron core, and arranged at substantially equal intervals in a circumferential direction,
the rotor iron core defines a plurality of magnetic poles arranged in the circumferential direction,
a magnetic barrier area is defined between adjacent magnetic poles in the circumferential direction, and
a conductor area is located at the radially outer side of the magnetic barrier area,
the magnetic barrier area is provided with a hole arranged in a plurality of layers in a radial direction and defining a magnetic barrier, and
the conductor area is provided with conductors, wherein:
a plurality of the conductors are arranged at substantially equal intervals in the circumferential direction and have substantially identical cross-sectional shapes as each other; and
the following relationship is satisfied:
Nc
=
{
2
×
[
Nt
/
(
2
×
Np
)
-
1
]
-
1
}
×
Np
,
where Nt is a number of the pole teeth, Np is a number of the magnetic poles, and Nc is a number of the conductors,
wherein circumferential ends of the hole of each layer are respectively opposed to a radially inner end of one of the conductors.
14 . The synchronous reluctance motor according to claim 13 , wherein
when viewed along an axial direction, the conductors have a strip shape extending in the radial direction, or
when viewed along the axial direction, two ends of the conductors in the radial direction are semicircular shapes, respectively, or
when viewed along the axial direction, intermediate portions between the two ends of the conductors in the radial direction have a tapered shape in which a circumferential width becomes narrower toward the inside in the radial direction.
15 . The synchronous reluctance motor according to claim 13 , wherein
the following relationship is satisfied:
Wt
≤
Dc
≤
1.5
Wt
,
where Dc is a distance between adjacent conductors in the circumferential direction, and Wt is a circumferential width of the pole teeth.
16 . The synchronous reluctance motor according to claim 13 , wherein
the rotor iron core has a circular hole centered on a rotation center of the rotor at a position radially inward of the magnetic barrier area, and
the following relationship is satisfied:
0.35
R
≤
Lc
≤
0.45
R
,
where Lc is a radial length of the conductors, and R is a radial distance between an outer circumferential surface of the rotor iron core and an inner circumferential surface of the circular hole.
17 . The synchronous reluctance motor according to claim 13 , wherein
the following relationship is satisfied:
Nb
<
Nt
/
(
4
Np
)
,
where Nb is a number of the layers.
18 . The synchronous reluctance motor according to claim 13 , wherein
when viewed along an axial direction, the hole of each of the layers respectively has a shape of arcs or straight lines.
19 . The synchronous reluctance motor according to claim 13 , wherein
circumferential widths of end portions in the circumferential direction of the each hole of each layer are smaller than a minimum circumferential width of an intermediate portion between both end portions in the radial direction of the conductor.
20 . The synchronous reluctance motor according to claim 13 , wherein
the rotor iron core comprises iron core sheets laminated in an axial direction; and
the following relationship is satisfied:
D
≥
T
,
where D is a distance between ends of the hole of each of the layers in the circumferential direction and ends of the conductors at a radially inner side, and T is a thickness of the iron core sheets.
21 . The synchronous reluctance motor according to claim 13 , wherein
the following relationship is satisfied:
θ
≤
360
/
(
2
×
Ns
×
Np
)
,
where θ is an angle defined by the d-axis and a line connecting the point Pt and the rotation center of the rotor under the condition that Pt being an intersection point of a tangent line at a circumferential end portion of a radially inner edge of a radially outermost hole and the outer circumferential surface of the rotor iron core, and Ns is a number of the magnetic poles.
22 . The synchronous reluctance motor according to claim 13 , wherein
the following relationship is satisfied:
Wo
≤
Wb
≤
0.5
Wt
where Wb is a circumferential width of a bridge, and Wo is an opening width of a groove between adjacent pole teeth in the circumferential direction, and Wt is a circumferential width of the pole teeth.
23 . The synchronous reluctance motor according to claim 13 , wherein
the hole of each of the layers is respectively provided with a magnet and respectively comprises a pair of divided holes divided by a bridge, which is a portion of the rotor iron core and located substantially on a q-axis,
the magnet comprises divided magnets provided adjacent to the q-axis in each of the divided holes, and
the following relationship is satisfied:
θ1
≥
(
3
×
360
)
/
Nt
,
a
nd
θ2
≥
θ1
where θ1 is an angle defined by lines which connect the rotation center of the rotor and circumferential both ends of a radially inner edge of the magnet in a radially outermost hole respectively, θ2 is an angle defined by lines which connect the rotation center of the rotor and circumferential both ends of a radially inner edge of the magnet in a radially innermost hole respectively.