JP2002119026A - Reluctance motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem where torque fluctuations are generated due to changes in the position relation between a coil in a slot and a rotor, even if a technique for reducing torque ripple is used by increasing the number of slots. SOLUTION: The number of slots 1b for each phase and each pole is doubled, and distribution of a magnetomotive force is smoothed, thereby reducing torque ripples. In order to restrain small torque fluctuation within one period of torque, a protruding part 6 is formed in a tip part of each salient pole 1a. The protruding length of the protruding part 6 is set to be different for each adjacent salient poles 1a, and increases magnetic flux of the salient pole 1a of the decrease side of torque. Thereby the generation torques in the salient pole 1a of the decrease side of torque is increased, and torque fluctuation within one period of torque is almost eliminated. In other words, torque ripples can be restrained fully.

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 A reluctance motor has the advantages of a large output torque and a simple structure. On the other hand, a reluctance motor has a high voltage every time an end of a magnetic insulating means (magnetic barrier) passes through a salient pole of a stator. There is a drawback that torque ripple occurs, and so far it has been used only in some fields.

[0003]

As a technique for reducing the torque ripple, there is known a technique of increasing the number of slots per pole and each pole of the stator to increase the number of slots. Due to the multi-slot configuration, the magnetomotive force distribution generated on the stator side changes smoothly, and the torque ripple is reduced. However, the positional relationship between the coil in the slot and the rotor changes due to the rotation of the rotor, and the magnetomotive force differs for each adjacent salient pole, so that torque fluctuation occurs within the magnetic pitch of each phase. . For this reason, even if the stator is multi-slotted, the torque ripple cannot be reduced sufficiently. An object of the present invention is to provide a reluctance type electric motor capable of reducing torque ripple caused by increasing the number of slots and reducing torque fluctuation caused by increasing the number of slots, thereby sufficiently reducing the torque ripple.

[0004]

According to the first aspect of the present invention, the magnetomotive force distribution generated on the stator side is made smoother by providing slots in two or more slots per pole for each phase. And the torque ripple decreases. Further, by adopting the means of claim 1, by providing the protrusion length of the protrusion provided at the tip of the salient pole so as to be different for each adjacent salient pole, the magnetic flux generated by the salient pole is reduced for each adjacent salient pole Can be different. For this reason, even if the positional relationship between the coil and the rotor in the slot changes due to the rotation of the rotor due to the increase in the number of slots, the average torque for each slot pitch can be equalized. For this reason,
It is also possible to sufficiently reduce the torque fluctuation that occurs when the stator has multiple slots. That is, by adopting the means of claim 1, the torque ripple can be reduced by increasing the number of slots, the torque fluctuation caused by increasing the number of slots can be reduced, and the torque ripple can be sufficiently reduced.

According to a second aspect of the present invention, the projection of the first aspect is provided by crushing a part of the connecting portion. If the crushed position or the crushed width is different for each adjacent salient pole, By doing so, it is possible to obtain the same effect as the case described in the means of the first aspect. That is, by adopting the means of claim 2, the number of slots per phase and each pole is provided in multiple slots of 2 or more, so that the magnetomotive force distribution generated on the stator side changes smoothly, The torque ripple decreases.

Further, the means of claim 2 is employed, and the crushing position or the crushing width of the connecting portion for connecting the tips between the salient poles is provided differently for each adjacent salient pole, thereby generating a salient pole. The magnetic flux can be made different for each adjacent salient pole. For this reason, even if the positional relationship between the coil and the rotor in the slot changes due to the rotation of the rotor due to the increase in the number of slots, the average torque for each slot pitch can be equalized. For this reason, the torque fluctuation that occurs when the stator is multi-slotted can be sufficiently reduced.
That is, by adopting the means of claim 2, the torque ripple can be reduced by increasing the number of slots, the torque fluctuation caused by increasing the number of slots can be reduced, and the torque ripple can be sufficiently reduced.

[0007]

Next, an embodiment of the present invention will be described with reference to FIG.
This will be described using two embodiments. First Embodiment First, a conventional reluctance motor will be described with reference to FIG. The conventional reluctance motor shown in FIG. 3 is equipped with three-phase coils of U-phase, V-phase, and W-phase, and has one slot for each pole and each phase. The reluctance type electric motor includes a stator 1 having a plurality of salient poles 1a facing the inner periphery at equal intervals,
And a rotor 2 whose magnetic resistance is different in the rotation direction when viewed from the front.
In b, coils of each phase are inserted in order to generate a magnetomotive force in each salient pole 1a.

The reluctance motor generates a magnetomotive force on the stator 1 at a predetermined angle with respect to the direction of the magnetic pole (d-axis) where the rotor 2 has the lowest magnetic resistance, and the rotor 2 has a low magnetic resistance. The output torque is obtained by rotating the portion in the magnetomotive direction of the stator 1. The direction of the magnetic pole (the virtual axis on control) where the magnetic resistance of the rotor 2 is lowest is generally d
The magnetic pole direction in which the magnetic resistance of the rotor 2 is the largest is generally called the q-axis.

The stator 1 is provided by laminating a plurality of stator lamination plates 3 each formed of an annular magnetic thin plate having a plurality of salient poles 1a facing the inner periphery at equal intervals. The rotor 2 is provided by laminating a plurality of rotor laminated plates 4 each made of a disk-shaped magnetic thin plate, and is provided with magnetic insulating means 5 for making the magnetic resistance different in the rotation direction. ing. The center angles of the magnetic poles formed on the rotor 2 are uniform, and in this embodiment, the rotor 2 has four magnetic poles.

The magnetic insulating means 5 is formed by laminating a flux barrier 5a (see FIG. 3) comprising a plurality of slits formed in the rotor laminated plate 4. This barrier 5a
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 5a so that the rotor 2 is not disassembled. The magnetic short circuit caused by this connection can be practically ignored by making the connection thinner.

FIG. 4 shows a torque waveform generated by the conventional reluctance motor shown in FIG. The conventional reluctance motor has a salient pole 1 a of the stator 1 and a slot 1.
Since the pitch of b is large and the distribution of the magnetomotive force is not smooth, the torque fluctuation within one cycle of the torque (the magnetic pitch of each coil phase) becomes large as shown by the solid line A in FIG.

Therefore, in the first embodiment, as shown in FIG. 5, the number of slots 1b per pole and each phase is doubled. With this arrangement, the salient poles 1 of the stator 1 are provided.
a and the pitch of the slot 1b become small, and the distribution of the magnetomotive force changes smoothly. Therefore, as shown by the solid line B in FIG. 6, the torque fluctuation within one cycle of the torque (in this case, the pitch of the two slots 1b) is reduced. And the torque ripple is reduced.

However, the positional relationship between the coil in the slot 1b and the rotor 2 changes with the rotation of the rotor 2. That is, when the rotor 2 rotates from the position shown in FIG. 5A to the position shown in FIG. 5B, the positional relationship between the rotor 2 and the coil differs. Then, as shown in FIG. 6, a small torque fluctuation occurs within one cycle of the torque (in this case, pitch of 2 slots and 1b). Specifically, as shown by a solid line B in FIG.
The torque increases and decreases for each pitch.

In order to prevent the torque from increasing or decreasing within one cycle of the torque, as shown in FIG.
A protrusion 6 protruding along the circumferential direction of the rotating shaft is provided, and the protrusion length of the protrusion 6 is provided to be different for each adjacent salient pole 1a. Specifically, salient pole 1 on the torque reduction side
In order to increase the magnetic flux a, the protruding length of the protrusion 6 of the salient pole 1a on the side where the torque decreases is increased, and the tip width of the salient pole 1a on the side where the torque decreases is increased to increase the amount of magnetic flux.

As a result, the salient pole 1a on the torque reduction side
, The torque fluctuation at each slot 1b pitch is reduced, and the average torque at each slot 1b pitch can be equalized, as shown by the solid line C in FIG. For this reason, even if the stator 1 is provided with multiple slots, the torque ripple can be sufficiently reduced. That is, the reluctance type electric motor shown in this embodiment can reduce the torque ripple by doubling the number of slots (multiple slots), and can also reduce the torque fluctuation caused by the multislots. The torque ripple can be made sufficiently small.

[Second Embodiment] A second embodiment will be described with reference to FIGS. In the second embodiment, the protrusion 6 shown in the first embodiment is constituted by a connecting member 7. The connecting member 7 includes all salient poles 1a facing the inner circumference.
Are connected annularly along the circumferential direction of the rotating shaft, and the connecting member 7 is provided integrally with the stator laminate 3. As shown in FIG. 8, the connecting member 7 is crushed at an intermediate portion between the salient poles 1a, and the crushed portion 7a
Are provided so as to increase the magnetic resistance.

The amount of magnetic flux at the leading end width of the salient pole 1a can be adjusted by the crushed position or the crushed width of the crushed portion 7a.
Therefore, in the second embodiment, in order to prevent the torque from increasing or decreasing within one cycle of the torque shown in FIG. 5 of the first embodiment, as shown in FIG. The crushing width was set to be different for each adjacent salient pole 1a. Specifically, salient pole 1 on the torque reduction side
The crushing position or the crushing width is set so as to increase the magnetic flux of a, and the amount of magnetic flux of the salient pole 1a on the torque reduction side is increased.
As a result, the generated torque at the salient pole 1a on the torque reduction side increases.

With this arrangement, similarly to the case of the first embodiment, the reluctance motor of the second embodiment also reduces the torque ripple by doubling the number of slots (multiple slots). In addition to this, torque fluctuations caused by the multi-slot operation can be reduced, and the torque ripple can be sufficiently reduced. Also, the tip of all salient poles 1a is
The stator 1 including each salient pole 1a
Increases the strength. Thereby, the operation noise of the reluctance type electric motor can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a stator laminate (first embodiment).

FIG. 2 is a graph showing a torque waveform (first embodiment).

FIG. 3 is a schematic diagram showing a basic structure of a reluctance type electric motor.

FIG. 4 is a graph showing a torque waveform of the reluctance motor of FIG. 3;

FIG. 5 is a schematic diagram of a multi-slot reluctance motor.

FIG. 6 is a graph showing a torque waveform of the reluctance motor of FIG. 5;

FIG. 7 is a view showing a stator laminate (second embodiment).

FIG. 8 is a perspective view of a main part of a stator laminate (second embodiment).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator 1a Salient pole 1b Slot 2 Rotor 3 Stator laminated plate 4 Rotor laminated plate 5 Magnetic insulating means 6 Projection 7 Connection member 7a Crushed part

Continuing from 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 Inside Denso Corporation (72 ) Inventor Yoshiyuki Takabe 390 Umeda, Kosai City, Shizuoka Prefecture Asmo Stock Company In-house F-term (reference) 5H002 AA01 AA09 AE07 5H619 AA01 AA07 AA10 BB01 BB06 BB24 PP01 PP05

Claims (2)

[Claims] 1. A rotor provided with a plurality of laminated sheets made of a magnetic thin plate and provided with magnetic insulating means for making a magnetic resistance different in a rotational direction, comprising: A reluctance electric motor that generates a magnetomotive force of the stator in a direction different from the direction of the magnetic pole having the lowest resistance, and generates a torque to rotate the magnetic pole of the rotor in the magnetomotive direction of the stator, The stator has a slot number of 2 or more per pole per phase, and a protrusion protruding along a circumferential direction of a rotating shaft is provided at a tip of a salient pole of the stator. Wherein the protrusion length of each of the adjacent salient poles is different for each of the adjacent salient poles. 2. A rotor provided with a plurality of laminated plates made of a magnetic thin plate and provided with magnetic insulating means for making the magnetic resistance different in the rotation direction, A reluctance electric motor that generates a magnetomotive force of the stator in a direction different from the direction of the magnetic pole having the lowest resistance, and generates a torque to rotate the magnetic pole of the rotor in the magnetomotive direction of the stator, The stator is provided with two or more slots per pole per phase, and the tips of all the salient poles of the stator are connected along the circumferential direction of the rotation axis by a connecting member integrated with the laminated plate. The reluctance motor is characterized in that the connection member is crushed and provided at an intermediate portion between the salient poles, and the crushing position or the crushing width is different for each adjacent salient pole.