JP5494767B2 - Permanent magnet reluctance motor rotor - Google Patents

Description

  The present invention relates to a rotor of a permanent magnet type reluctance motor, so that a large torque can be generated while making a through hole formed in the rotor as wide as possible in order to reduce the weight of the rotor and improve the cooling performance. It has been devised.

  In the permanent magnet type reluctance motor, a magnetic pole is formed by inserting and embedding a permanent magnet in the rotor, and magnetic reluctance (referred to as a d-axis) with a small magnetic resistance and easy passage of magnetic flux in the circumferential direction of the rotor; Magnetic recesses (referred to as q-axis) that have a large magnetic resistance and are difficult to pass magnetic flux are alternately formed.

By arranging such a rotor in a stator provided with a stator winding, the air gap magnetic flux between the stator and the rotor is high at the magnetic projection (d-axis), and magnetically Reluctance torque is generated by the change in the magnetic flux density.
Further, torque is also generated by a magnetic attractive force and a magnetic repulsive force between the permanent magnet and the magnetic pole of the stator (see, for example, Patent Documents 1 and 2).

  Such a permanent magnet type reluctance motor is also called an IPM (internal permanent magnet) type motor because a permanent magnet is inserted and embedded in the rotor.

  In such a permanent magnet type reluctance motor, in order to reduce the weight of the rotor and improve the cooling performance, it is possible to form through holes extending in the axial direction at a plurality of locations in the circumferential direction of the rotor. Yes (see, for example, Patent Document 2).

By forming the through hole in this way, the weight can be reduced and the weight can be reduced as much as the through hole is formed, and the controllability can be improved by reducing the moment of inertia (GD ² ) of the rotor. it can.
Furthermore, the cooling performance can be improved by circulating a liquid or gaseous cooling medium through the through hole.

Here, a permanent magnet type reluctance motor in which a through hole is formed in the rotor will be described with reference to FIG.
As shown in FIG. 8, the permanent magnet type reluctance motor 100 is configured by arranging a rotor 120 in a stator (not shown).

  In the rotor 120, magnet insertion holes 122a and 122b are formed in the rotor core 121, and permanent magnets 123a and 123b are inserted and fixed in the magnet insertion holes 122a and 122b.

  More specifically, the rotor core 121 is formed with two magnet insertion holes 122a and 122b extending in the axial direction at a plurality of locations in the circumferential direction (eight locations in this example). Has been. Each magnet insertion hole 122a, 122b has a rectangular cross-sectional shape. In addition, the magnet insertion hole 122a and the magnet insertion hole 122b are arranged so that the opposing distance between the magnet insertion hole 122a and the magnet insertion hole 122b increases sequentially along the radial direction toward the outer peripheral side. Therefore, the magnet insertion holes 122 a and 122 b are arranged in a “V shape” when viewed from the end surface of the rotor core 121.

  Then, permanent magnets 123a and 123b having a rectangular cross-sectional shape are inserted and fixed in the magnet insertion holes 122a and 122b, respectively. For this reason, the permanent magnet 123a and the permanent magnet 123b are arrange | positioned so that both opposing distance may increase sequentially as it goes to an outer peripheral side along a radial direction. Therefore, the permanent magnets 123 a and 123 b are arranged in a “V shape” when viewed from the end face of the rotor core 121.

  Here, an angle formed by the permanent magnet 123a and the permanent magnet 123b arranged in the “V shape” is defined as “magnet opening angle α”. That is, when the magnet opening angle α is viewed from the end surface of the rotor core 121, the long side (long side on the inner peripheral side) of the permanent magnet 123 a whose cross-sectional shape is rectangular and the cross-sectional shape are rectangular. An angle formed by the long side (long side on the inner peripheral side) of the permanent magnet 123b.

  In this way, the set permanent magnets 123a and 123b are arranged at equal intervals along the circumferential direction of the rotor 120, and the portion where the permanent magnets 123a and 123b are arranged has a large magnetic resistance. It becomes a magnetic recessed part (q-axis). Further, portions between the set permanent magnets 123a and 123b and the adjacent permanent magnets 123a and 123b are magnetic convex portions (d-axis) having a small magnetic resistance.

In the rotor core 121, a plurality of through holes 124 are formed side by side in a circumferential direction at a portion on the inner peripheral side from the position where the permanent magnets 123a and 123b are disposed, and the position where the through holes 124 are formed is formed. Furthermore, a plurality of through-holes 125 are formed in the circumferential direction on the inner peripheral side portion.
Each through hole 124 is formed so as to penetrate in the axial direction of the rotor core 121, and is arranged at equal intervals along the circumferential direction of the rotor core 121. Similarly, the through holes 125 are formed so as to penetrate in the axial direction of the rotor core 121, and are arranged at equal intervals along the circumferential direction of the rotor core 121.

  At this time, when viewed from the end surface of the rotor core 121, the side on the permanent magnet 123a, 123b side of the side of the through hole 124 and the side on the through hole 124 side of the side of the permanent magnet 123a, 123b are parallel. Yes.

  Here, when viewed from the end surface of the rotor core 121, the side of the permanent magnet 123 a on the side of the arbitrary through hole 124 and the side of the through hole 124 adjacent to the arbitrary through hole 124 on the permanent magnet 123 b side. The angle formed with the side of is defined as “through-hole opening angle β”.

  As described above, conventionally, when viewed from the end face of the rotor core 121, the side on the permanent magnet 123a, 123b side of the side of the through hole 124 and the side on the through hole 124 side of the side of the permanent magnet 123a, 123b are parallel. Therefore, the magnet opening angle α = the through hole opening angle β. For example, α = β = 135 °.

  Since the through holes 124 and 125 are formed in a portion of the rotor core 121 on the inner peripheral side with respect to the position where the permanent magnets 123 a and 123 b are disposed, There are few adverse effects.

By forming the through holes 124 and 125 in this way, the weight can be reduced by reducing the amount by which the through holes 124 and 125 are formed, and the inertia moment (GD ² ) of the rotor 120 can be reduced. Controllability can be improved.
Furthermore, the cooling performance can be improved by circulating a liquid or gaseous cooling medium through the through holes 124 and 125.

JP 2000-197287 A JP-A-2005-184957

  By the way, as shown in FIG. 8, conventionally, as viewed from the end surface of the rotor core 121, the permanent magnet 123 a, 123 b side of the through hole 124 side and the permanent magnet 123 a, 123 b side of the through hole 124 side. Since the sides were parallel, that is, the magnet opening angle α = the through hole opening angle β, the interval between the through hole 124 and the permanent magnets 123a and 123b was narrowed, and the magnetic flux density in this portion was It became high and was magnetically saturated.

When such magnetic saturation occurs, there is a problem that the magnet torque decreases.
Further, when magnetic saturation occurs, the magnetic flux does not pass any more, so that the value of inductance L (particularly q-axis inductance Lq) is saturated, thereby limiting the value of reluctance torque.

This phenomenon is shown based on FIGS. 9 to 11 which are magnetic flux analysis diagrams.
9 to 11 show a part of the permanent magnet type reluctance motor 100 extracted, and the state of the magnetic flux of the part is shown by a dotted line, FIG. 9 is a magnetic flux, FIG. 10 is a magnetic flux by d-axis current, 11 shows the magnetic flux by q-axis current.

As can be seen from FIGS. 9 and 11, the magnetic flux density is high in the portion between the permanent magnets 123a, 123b and the through hole 124 (the portion of region A in both drawings), and magnetic saturation occurs. I understand that.
In addition, as can be seen from FIG. 9, it can be seen that magnetic saturation occurs in the portion between the permanent magnets 123 a and 123 b and the through hole 124, particularly in the outer peripheral portion.

In order to simply cancel the magnetic saturation, the side on the permanent magnet 123a, 123b side of the side of the through hole 124 and the side on the through hole 124 side of the side of the permanent magnet 123a, 123b are kept parallel. That is, the distance between the permanent magnets 123a and 123b and the through hole 124 may be widened while maintaining the magnet opening angle α = the through hole opening angle β.
However, in this case, the opening area of the through hole 124 (the area viewed from the end face side of the rotor) is narrowed, and by forming the through hole 124, an attempt was made to reduce the weight and improve the cooling performance. It goes against the original purpose.

  The present invention provides a permanent magnet type reluctance motor having a large generated torque by eliminating magnetic saturation in a portion between a permanent magnet inserted into a rotor and a through hole formed in the rotor. For the purpose.

The configuration of the present invention for solving the above problems is as follows.
A plurality of magnet insertion holes, each having a rectangular cross-sectional shape, are formed at a plurality of locations in the circumferential direction of the rotor core so as to penetrate in the axial direction. The opposing distance of the magnet insertion holes increases sequentially along the radial direction toward the outside,
Further, a permanent magnet having a rectangular cross-sectional shape is inserted and fixed in the magnet insertion hole,
In the rotor iron core, a plurality of through holes penetrating in the axial direction are formed side by side in the circumferential direction in a portion on the inner circumferential side from the position where the permanent magnet is inserted and fixed.
In the rotor of a permanent magnet reluctance motor,
The through hole is disposed opposite to the permanent magnet;
The cross-sectional shape of the through-hole is a rectangular shape having four straight sides and four corners, and two corners at diagonal positions among the four corners are at the d-axis position,
The distance between the linear side on the permanent magnet side of the side of the through hole and the linear side on the side of the through hole among the sides of the permanent magnet increases from the inner peripheral side toward the outer peripheral side. The through holes are formed so as to increase gradually.

The configuration of the present invention is as follows.
When the magnet opening angle is α and the through hole opening angle is β, the ratio (β / α) between the magnet opening angle and the through hole opening angle is 1 <(β / α) ≦ (150/135) It is characterized by becoming.
Furthermore, the configuration of the present invention is as follows:
A second through-hole having a triangular cross-sectional shape is disposed at a position on the inner peripheral side with respect to the through-hole, and two sides of the side of the through-hole facing the side not facing the permanent magnet are triangular. A plurality of the elements are formed side by side in the circumferential direction.

  In the present invention, the distance between the linear side on the permanent magnet side of the through hole side and the linear side on the through hole side of the permanent magnet side increases from the inner peripheral side to the outer peripheral side. A through hole is formed so as to gradually increase. That is, the distance between the through hole and the permanent magnet is increased toward the outer peripheral side. For this reason, generation of magnetic saturation can be prevented and the magnet torque can be increased, and the reluctance torque can be increased by increasing the q-axis inductance Lq while keeping the d-axis inductance Ld constant. As a result, the total torque can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows the permanent-magnet-type reluctance motor which concerns on Example 1 of this invention. FIG. 3 is a magnetic flux analysis diagram showing magnet magnetic flux of Example 1. FIG. 3 is a magnetic flux analysis diagram showing magnetic flux due to d-axis current of Example 1. FIG. 3 is a magnetic flux analysis diagram showing a magnetic flux generated by the q-axis current of Example 1. The magnetic flux analysis figure which shows the magnet magnetic flux of Example 2. FIG. The magnetic flux analysis figure which shows the magnetic flux by d-axis current of Example 2. FIG. The magnetic flux analysis figure which shows the magnetic flux by the q-axis current of Example 2. The block diagram which shows the conventional permanent-magnet-type reluctance motor. The magnetic flux analysis figure which shows the magnet magnetic flux of the conventional permanent magnet type reluctance motor. The magnetic flux analysis figure which shows the magnetic flux by the d-axis current of the conventional permanent magnet type reluctance motor. The magnetic flux analysis figure which shows the magnetic flux by the q-axis current of the conventional permanent magnet type reluctance motor.

  Hereinafter, a permanent magnet type reluctance motor according to the present invention will be described in detail based on examples.

[Example 1]
As shown in FIG. 1, the permanent magnet type reluctance motor 1 according to the first embodiment of the present invention is configured by arranging a rotor 20 in a stator (not shown).

  In the rotor 20, magnet insertion holes 22a and 22b are formed in the rotor core 21, and permanent magnets 23a and 23b are inserted and fixed in the magnet insertion holes 22a and 22b.

  More specifically, the rotor core 21 is formed with two magnet insertion holes 22a and 22b extending in the axial direction at a plurality of locations in the circumferential direction (eight locations in this example). Has been. Each magnet insertion hole 22a, 22b has a rectangular cross-sectional shape. In addition, the magnet insertion hole 22a and the magnet insertion hole 22b are arranged so that the opposing distance between the magnet insertion hole 22a and the magnet insertion hole 22b increases sequentially toward the outer peripheral side along the radial direction. Therefore, the magnet insertion holes 22 a and 22 b are arranged in a “V shape” when viewed from the end face of the rotor core 21.

Then, permanent magnets 23a and 23b having a rectangular cross-sectional shape are inserted and fixed in the magnet insertion holes 22a and 22b, respectively. For this reason, the permanent magnet 23a and the permanent magnet 23b are arrange | positioned so that both opposing distance may increase sequentially as it goes to an outer peripheral side along a radial direction. Therefore, the permanent magnets 23 a and 23 b are arranged in a “V shape” when viewed from the end face of the rotor core 21.
In addition, "the cross-sectional shape is rectangular" of the magnet insertion holes 22a and 22b and the permanent magnets 23a and 23b means that the cross-sectional shape cut by a surface (surface along the radial direction) orthogonal to the rotation axis is a rectangle. means.

  Here, an angle formed between the permanent magnet 23a and the permanent magnet 23b arranged in the “V shape” is defined as “magnet opening angle α”. That is, the magnet opening angle α is a long side (long side on the inner peripheral side) of the permanent magnet 23a having a rectangular cross-sectional shape when viewed from the end surface of the rotor core 21, and a rectangular cross-sectional shape. An angle formed by the long side (long side on the inner circumference side) of the permanent magnet 23b.

  In this way, the set permanent magnets 23a and 23b are arranged at equal intervals along the circumferential direction of the rotor 20, and the portion where the permanent magnets 23a and 23b are arranged has a large magnetic resistance. It becomes a magnetic recessed part (q-axis). Further, the portions between the set permanent magnets 23a and 23b and the adjacent permanent magnets 23a and 23b are magnetic convex portions (d-axis) having a small magnetic resistance.

The rotor core 21 has a plurality (eight) through holes 24 in the circumferential direction corresponding to the permanent magnets 23a and 23b at the inner peripheral side of the position where the permanent magnets 23a and 23b are arranged. A plurality of through holes 25 are formed side by side in the circumferential direction further on the inner peripheral side than the position where the through holes 24 are formed.
Each through hole 24 is formed so as to penetrate in the axial direction of the rotor core 21, and is arranged at equal intervals along the circumferential direction of the rotor core 21. Similarly, the through holes 25 are formed so as to penetrate in the axial direction of the rotor core 21 and are arranged at equal intervals along the circumferential direction of the rotor core 21.

  At this time, when viewed from the end surface of the rotor core 21, the distance between the side of the through hole 24 on the side of the permanent magnets 23a, 23b and the side of the permanent magnets 23a, 23b on the side of the through hole 24 is The through hole 24 is formed so as to gradually increase from the inner peripheral side toward the outer peripheral side.

  Here, as viewed from the end face of the rotor core 21, the side on the permanent magnet 23 a side of the side of the arbitrary through hole 24 and the side of the through hole 24 adjacent to the arbitrary through hole 24 on the permanent magnet 23 b side. The angle formed with the side of is defined as “through-hole opening angle β”.

  As described above, when viewed from the end face of the rotor core 21, between the side of the through hole 24 on the side of the permanent magnets 23 a and 23 b and the side of the permanent magnets 23 a and 23 b on the side of the through hole 24. Since the distance gradually increases from the inner peripheral side toward the outer peripheral side, the magnet opening angle α <the through hole opening angle β. For example, α135 ° and β = 150 °.

  Since the through holes 24 and 25 are formed in a portion of the rotor core 21 on the inner peripheral side from the position where the permanent magnets 23a and 23b are disposed, There are few adverse effects.

By forming the through holes 24 and 25 in this way, the weight can be reduced by reducing the amount of the through holes 24 and 25 formed, and the inertia moment (GD ² ) of the rotor 20 can be reduced. Controllability can be improved.
Furthermore, the cooling performance can be improved by circulating a liquid or gaseous cooling medium through the through holes 24 and 25.

The torque T generated by the permanent magnet type reluctance motor 1 is generally expressed by the following formula (1).
T = P _n Φ _{m iq} + P _n (L _d −L _q ) i _d i _q (1)
However, each symbol has the following meaning.
T: Torque
P _n : Number of poles Φ _m : Magnetic flux of permanent magnet i _q : q-axis current i _d : d-axis current
L _q : q-axis inductance
L _d : d-axis inductance

In the right side of the above formula (1) representing the torque T, the first term represents the magnet torque and the second term represents the reluctance torque.
It can be seen that in order to increase the magnet torque, the magnet magnetic flux should be increased.
It can also be seen that in order to increase the reluctance torque, the d-axis inductance Ld is decreased to increase the q-axis inductance Lq, in other words, the salient pole ratio (Lq / Ld) is increased.

  In the first embodiment, when viewed from the end surface of the rotor core 21, between the side of the through hole 24 on the side of the permanent magnets 23 a and 23 b and the side of the permanent magnets 23 a and 23 b on the side of the through hole 24. Is gradually increased from the inner circumference side toward the outer circumference side. In other words, since the through hole opening angle β (150 °) is larger than the magnet opening angle α (135 °), it is permanent. The distance between the magnets 23a and 23b and the through hole 24 is wide (in particular, wide on the outer peripheral side).

  As a result, in the portion between the permanent magnets 23a and 23b and the through hole 24, magnetic saturation can be prevented, and the q-axis magnetic flux L can be reduced and the q-axis inductance Lq can be increased. Therefore, the magnet torque is increased by preventing magnetic saturation, and the reluctance torque can be increased by increasing the q-axis inductance Lq, so that the total torque of the permanent magnet type reluctance motor 1 is increased.

  In addition, in Example 1, the through hole opening angle β was increased, so that the magnet opening angle α = the through hole opening angle β and the interval between the permanent magnet and the through hole was simply widened compared with the case where the through hole opening angle β was maintained. The opening area of the hole 24 (the area seen from the end face side of the rotor) can be widened, and by forming the through-hole 24, the initial purpose of reducing the weight and improving the cooling performance can be achieved. .

Next, by making the through hole opening angle β (150 °) larger than the magnet opening angle α (135 °),
(1) In the portion between the permanent magnets 23a, 23b and the through hole 24, magnetic saturation can be prevented, and
(2) The fact that the q-axis magnetic flux L can be decreased and the q-axis inductance Lq can be increased is shown based on the magnetic flux analysis diagrams of FIGS.

  2 to 4 show a part of the permanent magnet type reluctance motor 1 extracted by the dotted line, and FIG. 2 shows the magnetic flux, FIG. 3 shows the magnetic flux due to the d-axis current, and FIG. 4 shows the magnetic flux by q-axis current.

  As can be seen from FIG. 2 and FIG. 4, the magnet opening angle α <the through hole opening angle β in the portion between the permanent magnets 23 a and 23 b and the through hole 24 (the portion of the region A in both drawings). It can be seen that magnetic saturation is eliminated as a result of the width of A becoming wider and the magnetic flux density being lowered, thereby increasing the magnet torque.

Further, in the portion between the permanent magnets 23a and 23b and the through hole 24 (the portion of the region A), the width of the region A is widened so that the magnet opening angle α <the through hole opening angle β, so that d as shown in FIG. While maintaining the magnetic flux density of the magnetic flux due to the axial current (that is, while keeping the d-axis inductance Ld constant), as shown in FIG. 4, the magnetic flux density of the magnetic flux due to the q-axis current can be reduced (that is, the q-axis inductance Lq is increased). can do).
Thus, it can be seen that the reluctance torque can be increased because the salient pole ratio (Lq / Ld) can be increased by increasing the difference between the d-axis inductance Ld and the q-axis inductance Lq.

Table 1 shows the permanent magnet type reluctance motor.
(1) The magnet opening angle α is set to 135 ° and no through hole is formed.
(2) Example 1 in which the magnet opening angle α is 135 ° and the through hole opening angle β is 150 °;
(3) A conventional product in which the magnet opening angle α is 135 ° and the through hole opening angle β is 135 °,
The torque with respect to each magnetomotive force phase difference is shown.

  From the results shown in Table 1, Example 1 in which the through hole opening angle β is 150 ° is larger in magnet torque, reluctance torque, and total torque than the conventional technology in which the through hole opening angle β is 135 °. I understand.

[Example 2]
Next, a permanent magnet type reluctance motor 1 according to a second embodiment of the present invention will be described with reference to FIGS.
5 to 7 show a part of the permanent magnet type reluctance motor 1 taken out and the state of the magnetic flux of the part is shown by a dotted line, FIG. 5 shows the magnetic flux, and FIG. 6 shows the magnetic flux by the d-axis current. FIG. 7 shows the magnetic flux due to the q-axis current.

In the second embodiment, the through hole 24a having a shape obtained by cutting the mountain portion (outer peripheral portion) of the through hole 24 in the first embodiment is formed.
That is, when viewed from the end face of the rotor core 21, the distance between the side of the through hole 24a on the side of the permanent magnet 23a, 23b and the side of the permanent magnet 23a, 23b on the side of the through hole 24a is Although gradually increasing from the inner peripheral side toward the outer peripheral side, the gradually increasing rate is larger in the outer peripheral side portion than in the inner peripheral side portion.
That is, the through hole opening angle is β at the inner peripheral side portion, but the through hole opening angle is γ larger than β at the outer peripheral side.

Thus, in Example 2, since the distance between the permanent magnets 23a and 23b and the through-hole 24 is wide especially on the outer peripheral side, as shown in FIGS. 5 to 7, the permanent magnets 23a and 23b Among the portions between the through holes 24, the magnetic flux density is lowered particularly in the outer peripheral side portion.
For this reason, generation | occurrence | production of magnetic saturation can be prevented reliably and a magnet torque can be enlarged.

DESCRIPTION OF SYMBOLS 1 Permanent magnet type reluctance motor 20 Rotor 21 Rotor core 22a, 22b Magnet insertion hole 23a, 23b Permanent magnet 24, 25 Through hole α Magnet opening angle β, γ Through hole opening angle

Claims (3)

A plurality of magnet insertion holes, each having a rectangular cross-sectional shape, are formed at a plurality of locations in the circumferential direction of the rotor core so as to penetrate in the axial direction. The opposing distance of the magnet insertion holes increases sequentially along the radial direction toward the outside,
Further, a permanent magnet having a rectangular cross-sectional shape is inserted and fixed in the magnet insertion hole,
In the rotor iron core, a plurality of through holes penetrating in the axial direction are formed side by side in the circumferential direction in a portion on the inner circumferential side from the position where the permanent magnet is inserted and fixed.
In the rotor of a permanent magnet reluctance motor,
The through hole is disposed opposite to the permanent magnet;
The cross-sectional shape of the through-hole is a rectangular shape having four straight sides and four corners, and two corners at diagonal positions among the four corners are at the d-axis position,
The distance between the linear side on the permanent magnet side of the side of the through hole and the linear side on the side of the through hole of the side of the permanent magnet increases from the inner peripheral side toward the outer peripheral side. A rotor of a permanent magnet type reluctance motor, wherein the through hole is formed so as to gradually increase. When the magnet opening angle is α and the through hole opening angle is β, the ratio (β / α) between the magnet opening angle and the through hole opening angle is 1 <(β / α) ≦ (150/135) The rotor of the permanent magnet type reluctance motor according to claim 1, wherein A second through-hole having a triangular cross-sectional shape is disposed at a position on the inner peripheral side with respect to the through-hole, and two sides of the side of the through-hole facing the side not facing the permanent magnet are triangular. The rotor of the permanent magnet type reluctance motor according to claim 1, wherein a plurality of the rotors are formed side by side in the circumferential direction.

Images