CN107124054B - Alternating pole permanent magnet motor and rotor thereof - Google Patents

Abstract

The invention discloses an alternate pole permanent magnet motor and a rotor thereof, wherein the rotor of the alternate pole permanent magnet motor comprises alternate poles, and the alternate poles are provided with guide grooves; the middle sections of the alternating poles are positioned between two side sections of the alternating poles along the circumferential direction of the rotor, and the slotting density of the side sections of the alternating poles is greater than that of the middle sections of the alternating poles; the slot density is the average width of the guide slots per unit length along the chord length of the arc structure of alternating poles. According to the rotor of the alternating-pole permanent magnet motor, the air gap density formed by the magnetic lines of force in the middle section of the alternating poles is improved, the symmetry of the magnetic density distribution of adjacent permanent magnet poles and the alternating poles is improved, the second harmonic distortion rate of counter electromotive force is reduced, and the iron core loss is reduced.

Description

Alternating pole permanent magnet motor and its rotor

technical field

The invention relates to the technical field of motors, in particular to an alternating pole permanent magnet motor and its rotor.

Background technique

The rotor of the alternating pole permanent magnet motor has permanent magnet poles and alternating poles distributed alternately along the rotor circumferential direction, the air gap density in the middle of the permanent magnet poles along the rotor circumferential direction is relatively large, and the air gap density in the middle of the alternating poles along the rotor circumferential direction is small, that is The symmetry of the adjacent permanent magnet poles and alternating poles is poor, so that the back EMF has a large second harmonic distortion rate, resulting in a large core loss; it will also cause a large vibration when the motor is running.

In addition, due to the lack of permanent magnets on the alternating poles and the lack of constraints on the magnetic force lines, the quadrature-axis armature reaction can easily change the direction of the magnetic force lines, resulting in distortion of the magnetic force lines and large torque ripples during motor operation.

To sum up, how to design the rotor of the alternating pole permanent magnet motor to reduce the second harmonic distortion rate of the back EMF and reduce the core loss is an urgent problem to be solved by those skilled in the art.

Contents of the invention

The purpose of the present invention is to provide a rotor of an alternating pole permanent magnet motor, so as to reduce the second harmonic distortion rate of back EMF and reduce core loss. The object of the present invention is to provide an alternating pole permanent magnet motor having the above rotor.

In order to achieve the above object, the present invention provides the following technical solutions:

A rotor of an alternating pole permanent magnet motor, comprising alternating poles, the alternating poles being provided with guide grooves;

Along the circumferential direction of the rotor, the middle section of the alternating pole is located between two side sections of the alternating pole, and the slot density of the side section of the alternating pole is greater than the slotting density of the middle section of the alternating pole;

The slot density is the average width of the guide slots per unit length along the chord length direction of the arc structure of the alternating poles.

Preferably, the guide groove extends along the direction of the magnetic force line at its location.

Preferably, the guide grooves are only provided on two side sections of the alternating poles.

Preferably, the guide groove is only provided on one side section of the alternating pole.

Preferably, the two side sections of the alternating poles are respectively the first side section of the alternating pole and the second side section of the alternating pole; along the rotation direction of the rotor, the first side section of the alternating pole in one of the alternating poles Located on the front side of the second side section of the alternating poles, the guide groove is only provided on the first side section of the alternating poles.

Preferably, the distances from the inner ends of any two guide slots near the rotor axis to the rotor axis are equal.

Preferably, the slot density of the alternating poles is not greater than 0.35.

Preferably, the guide groove has a width greater than 0.5mm.

Preferably, the guide groove is opened on the outer wall of the rotor.

Preferably, the guide groove is provided between the outer wall and the inner wall of the rotor.

Preferably, the guide groove is filled with non-magnetic conductive parts.

Preferably, the permanent magnets of the rotor have rare earth elements.

Based on the rotor of the alternating pole permanent magnet motor provided above, the present invention further provides an alternating pole permanent magnet motor, the alternating pole permanent magnet motor includes a rotor, and the rotor is the rotor described in any one of the above.

In the rotor of the alternating pole permanent magnet motor provided by the present invention, compared with the soft magnetic material of the rotor, the guide groove has a larger reluctance, and the magnetic force line will choose to pass through the place with less reluctance, that is, the magnetic force line will choose from Where there is no guide groove, since the slotting density of the two side sections of the alternating poles is greater than that of the middle section of the alternating poles, most of the magnetic force lines will pass through the middle section of the alternating poles, which improves the magnetic field lines in the middle section of the alternating poles. The formed air gap density improves the symmetry of the magnetic density distribution of the adjacent permanent magnet poles and alternate poles, thereby reducing the second harmonic distortion rate of the back EMF and reducing the core loss; at the same time, it also reduces Vibration generated when the motor is running.

Simultaneously, the rotor of the alternating pole permanent magnet motor provided by the present invention, since the guide grooves are set on the alternate poles, compared with the soft magnetic material of the rotor, the guide grooves have a larger reluctance, and the guide grooves increase the quadrature axis. The reluctance of the magnetic circuit weakens the change of the direction of the magnetic force line by the quadrature axis armature reaction, that is, reduces the influence of the quadrature axis armature reaction on the distribution of the magnetic force line, avoids the distortion of the magnetic force line, and avoids the large motor caused by the distortion of the magnetic force line. torque ripple.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

Fig. 1 is a kind of structural schematic diagram of the rotor of the alternating pole permanent magnet motor provided by the embodiment of the present invention;

Fig. 2 is another schematic structural view of the rotor of the alternating pole permanent magnet motor provided by the embodiment of the present invention;

Fig. 3 is a comparison diagram of the second harmonic distortion rate between the motor using the rotor of the alternating pole permanent magnet motor provided by the embodiment of the present invention and the alternating pole permanent magnet motor provided by the prior art;

Fig. 4 is a comparison diagram of the iron loss between the motor using the rotor of the alternating pole permanent magnet motor provided by the embodiment of the present invention and the alternating pole permanent magnet motor provided by the prior art;

Fig. 5 is a comparative diagram of torque between a motor using the rotor of an alternating pole permanent magnet motor provided by an embodiment of the present invention and an alternating pole permanent magnet motor provided by the prior art.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

As shown in Figure 1-2, the rotor of the alternating pole permanent magnet motor provided by the embodiment of the present invention includes alternating poles 2 and permanent magnet poles 1 distributed alternately along the circumference of the rotor, wherein the alternating poles 2 are provided with guide grooves 4, And the slotting density of the side section of the alternating pole 2 is greater than the slotting density of the middle section of the alternating pole 2, and the slotting density is the average width of the guide slot 4 per unit length along the chord length direction of the arc structure of the alternating pole 2 .

It can be understood that, along the circumferential direction of the rotor, the middle section of the alternating pole 2 is located between the two side sections of the alternating pole 2 . The chord direction of the arc-shaped structure of the alternating poles 2 is the width direction of the alternating poles 2 and also the width direction of the guide groove 4 . As shown in FIG. 1 , the width of the alternating pole 2 is L, and the width of the guide groove 4 is W.

Let the sum of the widths of all guide grooves 4 on one side section of the alternating pole 2 (when there is one guide groove 4 on the side section of the alternating pole 2, refer to the width of one guide groove 4) be W ₁ , alternate The width of the side section of the pole 2 is L ₁ , and the slot density of the side section of the alternate pole 2 is W ₁ /L ₁ .

Let the sum of the widths of all the guide grooves 4 on the other side section of the alternate pole 2 (when there is one guide groove 4 on the side section of the alternate pole 2, refer to the width of one guide groove 4) be W ₂ , The width of the side section of the alternating pole 2 is L ₂ , and the slot density of the side section of the alternating pole 2 is W ₂ /L ₂ .

Let the sum of the widths of all guide grooves 4 on the middle section of the alternating pole 2 (when there is one guide groove 4 on the middle section of the alternating pole 2, refer to the width of one guide groove 4) be W ₃ , the middle section of the alternating pole 2 The width is L ₃ , then the slotting density of the middle section of the alternating pole 2 is W ₃ /L ₃ .

Let the sum of the widths of all the guide grooves 4 on the alternate pole 2 (when there is one guide groove 4 on the alternate pole 2, refer to the width of one guide groove 4) be W ₄ , and the width of the alternate pole 2 be L, then The slot density of alternating poles 2 is W ₄ /L.

There can be one guide groove 4 on an alternate pole 2, or more than two guide grooves. When there are more than two guide grooves 4 on an alternate pole 2, any two guide grooves in any alternate pole 2 are preferred. 4 have the same width, at this time, the more the number of guide grooves 4, that is, the greater the density of guide grooves 4, the greater the groove density.

When there are more than two guide grooves 4 on one alternate pole 2, the guide grooves 4 on the alternate pole 2 are preferably distributed sequentially along the circumferential direction of the rotor.

For ease of description, the middle section of the alternating pole 2 is the middle section 23 of the alternating pole, and the two side sections of the alternating pole 2 are the first side section 21 of the alternating pole and the second side section 22 of the alternating pole. Along the circumferential direction of the rotor, the alternating pole first side segments 21 , the alternating pole middle segments 23 and the alternating pole second side segments 22 are distributed along the rotor's circumferential direction.

The rotor of the above-mentioned alternating pole permanent magnet motor is made of laminated soft magnetic sheets. The rotor is provided with a mounting groove, and the permanent magnet 3 is installed in the mounting groove. The polarity of the permanent magnet 3 facing the rotor axis of the permanent magnetic pole 1 is the same pole. sex. Two adjacent mounting slots are separated by soft magnetic material, which is magnetized into alternating poles 2 by adjacent permanent magnets 3 .

In the rotor of the alternating pole permanent magnet motor provided by the embodiment of the present invention, compared with the soft magnetic material of the rotor, the guide groove 4 has a larger reluctance, and the magnetic force line will choose to pass through the place with a smaller reluctance, that is The magnetic lines of force will choose to pass through the place where there is no guide groove 4. Since the slot density of the two side sections of the alternating pole 2 along the circumferential direction of the rotor is greater than the slot density of the middle section of the alternating pole 2, most of the magnetic line of force will pass through the alternating poles. The passage of the middle section of the pole 2 improves the magnetic field line to form a larger air gap density in the middle section of the alternating pole 2, which improves the symmetry of the magnetic density distribution of the adjacent permanent magnet pole 1 and the alternating pole 2, thereby reducing the back electromotive force. The second harmonic distortion rate reduces the core loss; at the same time, it also reduces the vibration generated when the motor is running.

At the same time, in the rotor of the alternating pole permanent magnet motor provided by the embodiment of the present invention, since the guiding groove 4 is provided on the alternating pole 2, compared with the soft magnetic material of the rotor, the magnetic resistance of the guiding groove 4 is relatively large, so The guide groove 4 increases the reluctance of the quadrature-axis magnetic circuit, weakens the change of the direction of the magnetic force lines by the quadrature-axis armature reaction, that is, reduces the influence of the quadrature-axis armature reaction on the distribution of the magnetic force lines, avoids the distortion of the magnetic force lines, and also avoids the distortion caused by the magnetic force lines. Distortion causes the motor to produce large torque ripple.

In the rotor of the above-mentioned alternating pole permanent magnet motor, there are at least two permanent magnet poles 1 and two alternating poles 2 , for example, three, four or six permanent magnet poles 1 and two alternating poles 2 .

For the convenience of production and manufacture, the above-mentioned guide groove 4 runs through both ends of the alternate poles 2 along the axial direction of the rotor.

Preferably, the above-mentioned guide groove 4 extends along the direction of the magnetic force line at its position. In this way, the increase of the reluctance of the guide groove 4 to the main magnetic circuit can be minimized to ensure the working performance of the motor.

The groove density in the middle of the alternating pole 2 may be zero, that is, there is no guide groove 4 in the middle of the alternating pole 2 .

There are two side sections of the above-mentioned alternating pole 2, and the groove density of the two side sections of the above-mentioned alternating pole 2 can be selected to be greater than zero, that is, both side sections of the alternating pole 2 are provided with guide grooves 4; The groove density of one side section of the pole 2 is zero, and the groove density of the other side section of the alternate pole 2 is greater than zero, that is, one side section of the alternate pole 2 is provided with a guide groove 4 .

In order to solve the above-mentioned technical problems, it is preferred to choose along the rotation direction of the rotor. In an alternating pole 2, the first side section 21 of the alternating pole is located on the front side of the second side section 22 of the alternating pole, and the guide groove 4 is only provided on the first side section of the alternating pole. twenty one.

The above arrangement prevents the maximum air-gap magnetic density of the alternating poles 2 from concentrating in the direction of rotation, causing the maximum air-gap flux density of the alternating poles 2 to deviate from the center position of the alternating poles 2, so that the detection of the rotor position is more accurate.

Certainly, the above-mentioned guide groove 4 may also be selected to be only provided on the second side section 22 of the alternate pole, and is not limited to the above-mentioned embodiment.

Preferably, the inner ends of any two guide grooves 4 close to the rotor axis are at the same distance from the rotor axis. Such setting can reduce the influence of the guide grooves 4 on the reluctance of the main magnetic circuit to ensure the normal operation of the rotor.

It can be understood that when the inner end surface of the inner end of the guide groove 4 is a plane, the distance between the inner end of the guide groove 4 and the rotor axis can be the distance from the middle of the inner end surface to the rotor axis, or the distance from the side end of the inner end surface to the rotor axis. Distance from the axis; when the inner end surface of the inner end of the guide groove 4 is an arc surface, the inner end of the guide groove 4 is on the same circle, and the center of the circle is on the axis of the rotor.

It should be noted that, along the circumferential direction of the rotor, the middle part of the inner end surface of the guide groove 4 is located between two side ends of the inner end surface of the guide groove 4 .

In the above-mentioned rotor with alternating pole permanent magnets, the greater the slot density, the smaller the sudden change in magnetic flux density on the outer periphery of the rotor.

Preferably, the slot density of the above-mentioned alternating poles 2 is not greater than 0.35. In this way, by controlling the slotting density of the alternating poles 2 within this range, the output of the motor will not be excessively reduced, and the distribution of the magnetic force lines on the alternating poles 2 is adjusted to the greatest extent.

Certainly, the groove density of the alternate poles 2 can also be selected as other values, and is not limited to the above-mentioned embodiment.

In order to facilitate processing, the width of the guide groove 4 is larger than 0.5 mm. In order to control the width of the guide groove 4 conveniently, the width of the guide groove 4 is compared with the thickness of the soft magnetic sheet of the rotor. Specifically, the width of the guide groove 4 is greater than the thickness of the soft magnetic sheet. Further, the above-mentioned soft magnetic sheet is a silicon steel sheet.

The upper limit of the width of the guide groove 4 is designed according to actual needs, as long as the rotor can run normally, which is not limited in the embodiment of the present invention.

In the rotor of the above-mentioned alternating pole permanent magnet motor, the guide groove 4 can have an opening away from the rotor axis, that is, the guide groove 4 is set on the outer wall of the rotor; it is also possible to choose that the guide groove 4 has no opening away from the rotor axis, that is, the guide groove 4 is set Between the outer and inner walls of the rotor, as shown in Figure 1 and Figure 2.

The above-mentioned guide groove 4 may be filled with non-magnetic permeable parts, or may not be filled with any components. When the guide groove 4 is filled with non-magnetic conductive parts, the specific material of the non-magnetic conductive parts can be selected according to actual needs, which is not limited in the embodiment of the present invention.

Preferably, the permanent magnet 3 of the above-mentioned permanent magnet pole 1 has rare earth elements. In this way, the performance of the permanent magnet 3 is effectively improved. The type of the rare earth element is designed according to actual needs, which is not limited in the embodiment of the present invention.

In the above-mentioned rotor of the alternating pole permanent magnet motor, the shape of the guide groove 4 can be designed according to actual needs, for example, the cross section of the guide groove 4 is triangular, quadrangular, or waist-shaped. Further, the cross section of the guide groove 4 is rectangular. It can be understood that the cross section of the guide slot 4 is perpendicular to the rotor axis.

When the guide groove 4 is irregular in shape, the width of a certain position of the guide groove 4 can be specified as the width of the guide groove 4, for example, the width of the inner end of the guide groove 4 close to the rotor axis can be specified as the width of the guide groove 4, or the width of the guide groove 4 can be specified. The width of the outer end of the guide groove 4 away from the rotor axis is the width of the guide groove 4 and the like.

In order to more clearly illustrate the advantages of the rotor of the above-mentioned alternating pole permanent magnet motor, the motor using the rotor of the above-mentioned alternating pole permanent magnet motor is tested in the same environment as the existing alternating pole permanent magnet motor, as shown in Figure 3- 5. In Fig. 3-5, the existing motor is the existing alternating pole permanent magnet motor, and the motor of the present invention is a motor using the rotor of the alternating pole permanent magnet motor provided by the embodiment of the present invention.

Specifically, as shown in Figure 3, a comparison chart of the second harmonic distortion rate of the back EMF is obtained, and it can be seen that the second harmonic distortion rate of the back EMF of the motor of the present invention has been effectively reduced and improved; as shown in Figure 4 As shown in Fig. 5, the comparison chart of iron loss is obtained, and it can be seen that the iron loss of the motor of the present invention has been effectively improved; improved.

It should be noted that in FIG. 5 , the curve with black dots represents the variation of torque of the motor of the present invention with time, and the curve without black dots represents the variation of torque of the conventional motor with time.

Based on the rotor of the alternating pole permanent magnet motor provided in the above embodiment, the embodiment of the present invention also provides an alternating pole permanent magnet motor, the alternating pole permanent magnet motor includes a rotor, and the rotor is the alternating pole permanent magnet motor described in the above embodiment. The rotor of the magneto.

Since the rotor of the alternating pole permanent magnet motor provided by the above embodiment has the above technical effect, and the above alternating pole permanent magnet motor has the rotor of the above alternating pole permanent magnet motor, then the above alternating pole permanent magnet motor also has the corresponding technical effect, which is not described herein. Let me repeat.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (13)

1. Rotor of an alternating pole permanent magnet machine, comprising alternating poles (2), characterized in that the alternating poles (2) are provided with guiding grooves (4);

the middle sections of the alternating poles (2) are positioned between two side sections of the alternating poles (2) along the circumferential direction of the rotor, and the slotting density of the side sections of the alternating poles (2) is greater than that of the middle sections of the alternating poles (2);

the grooving density is the average width of the guide groove (4) per unit length along the chord length direction of the arc-shaped structure of the alternating poles (2).

2. A rotor according to claim 1, characterized in that the guide slot (4) extends along the course of the magnetic field lines at its location.

3. A rotor according to claim 1, characterized in that the guide slots (4) are provided only at two side sections of the alternating poles (2).

4. A rotor according to claim 1, characterized in that the guide slots (4) are provided only at one side section of the alternating poles (2).

5. The rotor as set forth in claim 4, wherein,

the two side sections of the alternating pole (2) are respectively an alternating pole first side section (21) and an alternating pole second side section (22);

in the rotation direction of the rotor, the first side sections (21) of the alternate poles (2) are positioned at the front side of the second side sections (22) of the alternate poles, and the guide grooves (4) are only arranged on the first side sections (21) of the alternate poles.

6. A rotor according to claim 1, characterized in that the inner ends of any two of the guide grooves (4) close to the rotor axis are equidistant from the rotor axis.

7. A rotor according to claim 1, characterized in that the slotting density of the alternating poles (2) is not greater than 0.35.

8. A rotor according to claim 1, characterized in that the width of the guide groove (4) is greater than 0.5mm.

9. A rotor according to claim 1, characterized in that the guide groove (4) is open on the outer wall of the rotor.

10. A rotor according to claim 1, characterized in that the guide groove (4) is arranged between the outer wall and the inner wall of the rotor.

11. A rotor according to claim 1, characterized in that the guide groove (4) is filled with a non-magnetically conductive member.

12. A rotor according to claim 1, characterized in that the permanent magnets (3) of the rotor have rare earth elements.

13. An alternating pole permanent magnet machine comprising a rotor, wherein the rotor is as claimed in any one of claims 1 to 12.

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