JP2001352724A - Reluctance electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems that windings with different phase are disposed in a slot and the occupation rates of the respective winding are low because there is only a winding of a conventional synchronous reluctance electric motor enclosing a plurality of salient poles, and an axial dimension is large because the winding part protruding from the slot overlaps an adjacent winding. SOLUTION: This reluctance electric motor is formed so that the number of magnetic poles Np of a rotor 2 and the number of slots Ns of a rotor 1 may satisfy the relationship of Ns=3×Np, a winding 3 may be wound so as to enclose only a salient pole 1a, the winding directions of the adjacent windings 3 may be opposite to each other, and the rotor 2 may be rotatably driven by supplying three-phase current to the respective phase of windings 3. With this structure, an slot area which permits the winding 3 to be inserted can be increased, and the winding number of the winding 3 can be increased to more than twice as much as that of the conventional winding, thereby exerting performance that is equal to or better than that of the conventional winding. The winding part protruding from the slot will not overlap the adjacent winding 3, thus it is possible to reduce the axial dimension, in other words, attain miniaturization while keeping the performance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reluctance type electric motor that obtains a rotational force by utilizing a difference in magnetic resistance of a rotor with respect to a stator.

[0002]

2. Description of the Related Art The conventional structure of a reluctance motor is as follows.
[Matsushita Technical Jou
rnal Vol. 44], a winding is wound so as to surround a plurality of salient poles of the stator, and a sine-wave current is applied to the winding, so that the stator is A rotating magnetic field distribution having a sine wave shape is generated, and a rotating torque is generated in the rotor using the difference between the rotating magnetic field and the magnetic resistance of the rotor.

[0003]

However, in the case where the winding is wound so as to surround a plurality of salient poles, there is the following problem. a) Since windings of different phases are arranged in one slot, the space factor of each winding (the ratio of the winding cross-sectional area to the slot area) decreases. b) Since the coil end of each winding (the winding part protruding from the slot) overlaps with the coil end of the adjacent winding,
The axial dimension of the winding becomes large. For such a reason, the conventional reluctance type electric motor has a problem that the size is increased. An object of the present invention is to provide a reluctance type electric motor that can be made smaller than before without deteriorating performance.

[0004]

According to the first aspect of the present invention, the distribution of the rotating magnetic field on the stator side is that of a conventional winding (the winding is wound so as to surround a plurality of salient poles). Therefore, as in the related art, a rotating torque can be generated in the rotor. Further, since the winding surrounds only one salient pole, the space factor of the winding is improved as compared with a conventional case where the winding surrounds a plurality of salient poles. As described above, by improving the space factor of the winding surrounding only one salient pole, the magnetomotive force generated by the winding can be improved, and performance equal to or higher than that of the related art can be exhibited. Further, since the winding surrounds only one salient pole, the coil end of each winding does not overlap with the coil end of an adjacent winding. For this reason, the dimension of the winding in the axial direction can be reduced as compared with the related art, and the reluctance motor can be reduced in size as compared with the related art.

[0005] By adopting the means of claim 2, fluctuations in the generated torque can be offset, and torque ripple can be reduced. In addition, the magnetic resistance difference does not become small depending on the rotor position as in the conventional technology (a technology in which the magnetic center angle of the rotor or the stator is skewed by one slot angle in the rotation direction to reduce the torque ripple). The output torque does not decrease. That is, a reluctance motor having high output torque and low torque ripple can be obtained.

According to the third aspect of the present invention, since the barriers of a plurality of adjacent laminated plates are the same, the flow of magnetic flux in the axial direction generated at the overlapping portion of the adjacent laminated plates can be reduced. Thus, the effect of reducing torque ripple can be enhanced.

[0007] By adopting the means of claim 4, 1
The same effects as those of the second aspect can be obtained by using a kind of laminated plate. That is, by using a rotor in which one type of laminated plate having a plurality of types of barrier patterns is laminated, fluctuations in the generated torque can be offset without causing a decrease in output, and torque ripple can be suppressed.

By employing the means of claim 5, the area of the magnetic portion of the salient pole can be increased, so that more magnetic flux can flow through the salient pole and the output can be increased. In addition, the effect of magnetic saturation can be reduced.

By adopting the means of claim 6, it is possible to absorb the influence of the assembly error in the axial direction between the rotor and the stator. Also, as the axial dimension of the stator becomes smaller, the length of the winding becomes shorter and copper loss (electrical resistance) increases.
Can be reduced.

[0010] By adopting the means of claim 7, it is possible to absorb the influence of the assembly error in the axial direction between the rotor and the stator. Further, the inertia of the rotor can be reduced by reducing the axial dimension of the rotor.

According to the eighth aspect, the magnetic field distribution on the stator side changes smoothly.
Torque ripple can be reduced. Further, the amount of magnetic flux flowing into the rotor can be increased, so that the average torque can be improved.

[0012]

Next, embodiments of the present invention will be described with reference to a plurality of examples. FIG. 1 is a schematic diagram of a reluctance type electric motor. The reluctance type electric motor includes a stator 1 having a plurality of salient poles 1a at equal intervals toward the inner periphery, and a rotor 2 having a magnetic resistance different from the stator 1 in the rotational direction as viewed from the stator 1. Around the salient pole 1a, a winding 3 for generating a magnetomotive force on the salient pole 1a is mounted. The winding 3 will be described later.

The reluctance motor generates a magnetomotive force in a salient pole 1a at a predetermined angle with respect to the direction of the magnetic pole (d-axis) of the rotor 2 where the magnetic resistance is the lowest. The rotational output is obtained by rotating the salient pole 1a in the direction of the magnetomotive force. The direction of the magnetic pole with the lowest magnetic resistance of the rotor 2 (imaginary axis in control) is generally called the d-axis, and the direction of the magnetic pole with the highest magnetic resistance of the rotor 2 is generally called the q-axis.

The stator 1 is formed by laminating a large number of stator lamination plates 4 each formed of an annular magnetic thin plate having a plurality of (12 in this embodiment) salient poles 1a facing the inner periphery at equal intervals. It is provided. The rotor 2 is provided by laminating a number of rotor laminated plates 5 each formed of a thin disk made of a magnetic material having a disk shape. Each rotor laminated plate 5 constituting the rotor 2 includes a rotor A plurality of barriers 6 are provided to make the magnetic resistances 2 different in the rotation direction. The central angles of the magnetic poles formed on the rotor 2 are uniform, and in this embodiment, one rotor laminated plate 5 has four magnetic poles having a central angle of 90 degrees.

The barrier 6 formed on the rotor laminated plate 5 includes:
The slit has an arc shape curved inward, and is provided in a target shape around the q axis. The slit may be filled with a non-magnetic material such as resin or aluminum,
It may be a void. In this embodiment, a small connecting portion is provided on the outer peripheral end of the barrier 6 so that the rotor 2 is not disassembled. The magnetic short circuit due to this connection
Practically negligible by thinning the connection.

The relationship between the number Np of magnetic poles of the rotor 2 and the number Ns of slots in which the windings 3 are mounted is provided so as to satisfy Ns = 3 × Np. Specifically, in this embodiment,
As described above, the number of magnetic poles of the rotor 2 is Np = 4,
The number of slots Ns = 12.

Here, the winding 3 of the reluctance motor of this embodiment will be described in comparison with the winding 3 'of the conventional reluctance motor shown in FIG. The winding 3 'of the conventional reluctance motor is wound so as to surround three salient poles 1a, as shown in FIG. Adjacent windings 3 'in the same phase are wound in opposite directions. It should be noted that the winding 3 'is also wound over the entire circumference in accordance with the above-described pattern at the portion where the winding 3' is not shown.

Then, a sine-wave current whose phases are shifted by 120 degrees in electrical angle from each other as shown in FIG. 3 is applied to each winding 3 ′, so that a sine-wave-like rotating magnetic field distribution is applied to the stator 1 side. And a rotational torque is generated in the rotor 2 by utilizing a difference in magnetic resistance of the rotor 2 caused by the barrier 6.

On the other hand, as shown in FIG. 1, the windings 3 of the reluctance motor of this embodiment are wound so as to surround only one salient pole 1a. Is wound in the opposite direction, and a sine wave current in which each phase is shifted by 120 degrees in electrical angle as shown in FIG. . In addition, also in the part where the winding 3 is not shown,
The winding 3 is wound over the entire circumference according to the above pattern.

When the number of turns of the winding 3 of this embodiment (FIG. 1) and that of the conventional winding 3 '(FIG. 2) are the same, the stator (1) of the reluctance type electric motor of this embodiment is A rotating magnetic field distribution having a size 1/2 that of FIG. 2) and a similar distribution is generated. As a result, when the same current is applied, half the torque of the related art (FIG. 2) is generated. Accordingly, the number of turns of the winding 3 (FIG. 1) of the present embodiment is two times as compared with the conventional case (FIG. 2).
By doubling the torque, a torque equivalent to that of the related art (FIG. 2) can be obtained.

Here, since the winding 3 (FIG. 1) of this embodiment surrounds only one salient pole 1a, the winding 3 surrounds the three salient poles 1a as in the prior art (FIG. 2). In comparison, the slot area in which the winding 3 can be inserted is increased, and the winding 3
The space factor is greatly improved. As described above, by improving the space factor of the winding 3, the number of turns of the winding 3 can be made twice or more as compared with the related art (FIG. 2), and the same performance as that of the related art (FIG. 2) is exhibited. It becomes possible.

The winding 3 (FIG. 1) of this embodiment surrounds only one salient pole 1a, whereas the conventional winding 3 '(FIG. 2) straddles the three salient poles 1a. Therefore, the length of the portion that cannot be accommodated in the slot can be reduced to 1/3 or less. Furthermore, since the winding 3 surrounds only one salient pole 1a, it does not overlap with the adjacent winding 3.
For this reason, the axial dimension of the winding 3 can be reduced as compared with the conventional case (FIG. 2), and the reluctance motor can be made smaller than the conventional case (FIG. 2).

Further, since the conventional winding 3 '(FIG. 2) straddles the three salient poles 1a, it is difficult to mount the previously formed winding 3' on the stator 1, and the stator 3 Although the winding 3 'is wound directly on the stator 1, the winding 3 (FIG. 1) of the present embodiment surrounds only one salient pole 1a. It becomes possible to do. This simplifies the winding process,
The manufacturing cost for the winding step can be reduced. Further, since the winding 3 can be formed before the stator 1 is mounted,
It becomes possible to wind the winding 3 densely and appropriately.
As a result, the space factor of the winding 3 can be further improved, and the output can also be improved by this technique.

As described above, the reluctance type electric motor of the present embodiment can be reduced in size while maintaining performance equal to or higher than that of the conventional one, and can further reduce the cost.

[Second Embodiment] Referring to FIGS.
An embodiment will be described. As described in the first embodiment, the rotor 2 is provided by laminating a large number of rotor laminated plates 5 each formed of a disk-shaped magnetic thin plate. The lamination of the formed barriers 6 provides the rotor 2 with magnetic poles having a uniform central angle. The rotor 2 of this embodiment is obtained by alternately laminating two types of rotor laminated plates 5 (barrier specifications A and barrier specifications B) in which barriers 6 are formed at different positions.
The position of the barrier 6 is different.

More specifically, the rotor laminate 5 of the barrier specification A shown in FIG. 4A and the barrier specification B shown in FIG.
5 are alternately laminated as shown in FIG. 5, and the relationship between the positions of the barriers 6 in the barrier specification A and the barrier specification B is shown by a solid line and a broken line in FIG. In this embodiment, when the rotor 2 is viewed from the circumferential direction, the intervals between the outer peripheral end of the barrier 6 and the outer peripheral end of the barrier 6 adjacent thereto are all equal within the same magnetic pole. Is provided.

Here, the torque waveform generated by the rotor laminate 5 of the barrier specification A is shown by a solid line A in FIG. 6, and the torque waveform generated by the rotor laminate 5 of the barrier specification B is shown by a broken line B in FIG. Show. As shown in this graph, the torque waveform generated by the rotor laminate 5 of the barrier specification B has an opposite phase to the torque waveform generated by the rotor laminate 5 of the barrier specification A. The torque generated by the rotor 2 is the sum of the torque generated by the rotor laminated plate 5 of the barrier specification A and the torque generated by the rotor laminated plate 5 of the barrier specification B. Fluctuations are offset, resulting in reduced torque ripple. Further, in this embodiment, there is no problem that the magnetic resistance difference at the rotational position is small unlike the related art (the technique of skew), and the output torque is not reduced. That is, the reluctance type electric motor in this embodiment has high output torque and low torque ripple.

Further, in this embodiment, when the rotor 2 is viewed from the circumferential direction, the interval between the outer peripheral end of the barrier 6 and the outer peripheral end of the barrier 6 adjacent thereto is equally spaced within the same magnetic pole. With the provision, the torque fluctuation generated when each barrier end passes through the salient pole 1a is regularly and clearly clarified. For this reason, the degree of offset of the torque fluctuation increases, and the effect of reducing the torque ripple can be enhanced.

[Third Embodiment] When the rotor 2 is constructed by alternately stacking the rotor laminated plates 5 of the barrier specification A and the barrier specification B as in the second embodiment, the axial direction Since the magnetic flux flows, the effect of reducing the torque ripple due to the displacement of the barrier 6 is reduced. Accordingly, in the third embodiment, as shown in FIG. 7, a rotor block 2a in which the rotor laminated plates 5 of the barrier specification A are stacked and a rotor block in which the rotor laminated plates 5 of the barrier specification B are stacked. Block 2
b to form a rotor 2. With this arrangement, the degree of the magnetic flux flowing in the axial direction is reduced, and the effect of reducing the torque ripple can be enhanced. In addition, since the lamination of the rotor laminations 5 is easier than the lamination of the specifications of the rotor laminations 5 alternately, an effect of improving the assemblability can be obtained.

[Fourth Embodiment] In a fourth embodiment, as shown in FIG. 8, a barrier pattern of barrier specification A and a barrier pattern of barrier specification B are provided on the same rotor laminated plate 5. The rotor 2 is formed by laminating the rotor laminated plates 5 having these two types of barrier patterns.

With this arrangement, the same effect as in the second embodiment can be obtained. Further, similarly to the third embodiment, the degree of the magnetic flux flowing in the axial direction is small, and a high torque ripple reduction effect can be obtained. Further, since the rotor 2 is configured by laminating one kind of the rotor laminated plates 5, the lamination of the rotor laminated plates 5 becomes easy, and an effect of improving the assemblability can be obtained.

Fifth Embodiment In the fifth embodiment, as shown in FIG. 9, the width b in the rotational direction at the root of the salient pole 1a is wider than the width a in the rotational direction at the tip of the salient pole 1a. (B> a). Specifically, in the fifth embodiment, the salient pole 1a has a shape in the rotating direction in which a rounded portion is provided at the root portion of the salient pole 1a, and a tip side is provided in a trapezoidal shape having a shorter side than the root portion. Is adopted.

When the root portion of the salient pole 1a becomes thick as described above, the concentration of magnetic flux at the root portion is reduced, and more magnetic flux can flow through the salient pole 1a. Also,
By alleviating the magnetic saturation of the salient poles 1a, it is possible to prevent performance degradation due to magnetic saturation. Furthermore, salient pole 1
By adopting a trapezoidal shape in which the root portion of a is thickened, the shape of the slot changes from a trapezoidal shape to a rectangular shape, so that the winding 3 can be effectively mounted in the slot and the space factor of the winding 3 is improved. be able to.

[Sixth Embodiment] The sixth embodiment is similar to that of FIG.
As shown in the figure, the axial dimension L1 of the rotor 2 is
Is provided longer than the axial dimension L2 (L1>
L2). Specifically, the number of laminated rotor laminated plates 5 (see the first embodiment) constituting the rotor 2 is the same as the number of laminated laminated plates 4 (see the first embodiment) constituting the stator 1. More than the number, the rotor 2 is provided with the axial dimension L1 longer than the stator 1 axial dimension L2.

If the axial lengths of the stator 1 and the rotor 2 are the same, if an error occurs in both the stator 1 and the rotor 2 in the axial direction due to an assembly error, the shaft is not energized during the energizing operation. A force in the direction is generated, and the behavior of the motor becomes unstable, which causes vibration. On the other hand, by providing the axial dimension L1 of the rotor 2 longer than the axial dimension L2 of the stator 1 as in the sixth embodiment, the assembly error in the axial direction can be reduced by the dimensional difference (L1-L2). As a result, no axial force is generated, and vibration can be prevented. In addition, since the axial dimension of the stator 1 is reduced, the length of the winding 3 is reduced, and copper loss can be reduced.

[Seventh Embodiment] The seventh embodiment is similar to that of FIG.
, The axial dimension L2 of the stator 1 is
(L2>).
L1). Specifically, the number of laminated stator laminated plates 4 (see the first embodiment) constituting the stator 1 is equal to the number of laminated laminated plates 5 (see the first embodiment) constituting the rotor 2. More than the number, the axial dimension L2 of the stator 1 is consequently longer than the axial dimension L1 of the rotor 2.

With this arrangement, as in the sixth embodiment, the axial assembly error between the stator 1 and the rotor 2 can be absorbed by the dimensional difference (L2-L1). No force is generated, and the generation of vibration can be prevented. In addition, since the axial dimension of the rotor 2 is reduced, the inertia of the rotor 2 can be reduced, and the responsiveness of the electric motor improves.

[Eighth Embodiment] The eighth embodiment is similar to that of FIG.
As shown in the figure, the tip of the slot 1b on the rotor 2 side is
It is closed by a closing portion 7 (magnetic material) integrated with the salient pole 1a. With this arrangement, the magnetic field distribution on the stator 1 side changes smoothly, so that torque ripple can be reduced. In addition, since the amount of magnetic flux flowing into the rotor 2 can be increased, the average torque can be improved. In addition, the closing part 7 of FIG.
Is to close a part of the tip on the rotor 2 side, but may be provided to close the tip on the rotor 2 side of the slot over the entire circumference in the rotation direction.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a three-phase reluctance motor (first embodiment).

FIG. 2 is a schematic diagram of a three-phase reluctance motor (prior art).

FIG. 3 is a graph showing a current waveform (first embodiment).

FIG. 4 is a view showing a barrier pattern of a rotor laminate (second embodiment).

FIG. 5 is an explanatory diagram of a laminated state of a rotor laminated plate (second example).
Example).

FIG. 6 is a graph showing a torque waveform (second embodiment).

FIG. 7 is an explanatory diagram of a laminated state of a rotor laminated plate (third embodiment);
Example).

FIG. 8 is a plan view of a rotor laminated plate (fourth embodiment).

FIG. 9 is a view showing a shape of a salient pole (fifth embodiment).

FIG. 10 is a view showing a dimension difference in an axial direction between a stator and a rotor (sixth embodiment).

FIG. 11 is a diagram showing a difference in axial dimension between a stator and a rotor (seventh embodiment).

FIG. 12 is a diagram showing a slot shape of a stator (eighth embodiment);
Example).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator 1b Slot 1a Salient pole 2 Rotor 3 Winding 4 Stator laminated plate 5 Rotor laminated plate 6 Barrier 7 Closed part (magnetic material)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hideharu Yoshida 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Kenji Inokuma 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Denso Corporation (72) Inventor Yoshiyuki Takabe 390 Umeda, Kosai City, Shizuoka Prefecture Asmo Co., Ltd. In-house (72) Inventor Masami Fujitsuna 1-1-1, Showa-cho, Kariya City, Aichi Prefecture F-term (reference) 5H002 AA02 AA05 AA09 AE06 AE07 5H603 AA01 AA09 BB07 BB09 BB12 CA01 CA05 CB02 CC05 CD21 5H619 AA01 BB01 BB06 BB15 BB24 PP01 PP02 PP04 PP05 PP14

Claims (8)

[Claims] A stator that generates a magnetomotive force; and a rotor that is rotatably driven by the magnetomotive force generated by the stator, wherein the magnetic resistance of the rotor as viewed from the stator side is: A barrier or groove is provided in the stator so as to have a different structure in the rotation direction depending on the rotor position, and the magnetomotive force of the stator is generated in a direction different from the direction of the magnetic pole, which is a portion of the rotor having low magnetic resistance. And a reluctance motor that generates a torque to rotate the magnetic poles of the rotor in the direction of the magnetomotive force of the stator. The number of magnetic poles Np of the rotor and the number of slots Ns of the stator
Is Ns = 3 × Np, and the windings that generate the magnetomotive force in the stator are wound so as to surround only one of the salient poles of the stator, and are adjacent to each other. A reluctance type electric motor characterized in that the winding directions of the windings are reversed, and the rotor is rotationally driven by applying a three-phase current to each winding. 2. The reluctance type electric motor according to claim 1, wherein said rotor is provided by laminating a plurality of types of laminated plates having different positions or numbers of said barriers or different barrier widths. Electric motor. 3. The reluctance type electric motor according to claim 2, wherein the rotor is provided by joining a plurality of blocks having the same kind of laminated plates adjacent to each other. 4. The reluctance motor according to claim 1, wherein the center angle of each magnetic pole of the rotor is uniform, and the rotor is formed by laminating a laminate having a plurality of types of barrier patterns formed in the magnetic pole. A reluctance-type electric motor characterized by being provided as follows. 5. The reluctance type electric motor according to claim 1, wherein the salient pole has a shape in a rotation direction in which an R portion is provided at a root portion or a tip side on the rotor side. A reluctance motor having a trapezoidal shape having a shorter side than a root portion. 6. The reluctance type electric motor according to claim 1, wherein an axial dimension of said rotor is longer than an axial dimension of said stator. Electric motor. 7. The reluctance type electric motor according to claim 1, wherein an axial dimension of the stator is provided to be longer than an axial dimension of the rotor. Electric motor. 8. The reluctance type electric motor according to claim 1, wherein a part or all of a tip of the slot into which the winding is inserted on the rotor side is a magnetic material. Characteristic reluctance motor.