CN115528834A

CN115528834A - Self-starting permanent magnet synchronous motor and rotor structure thereof

Info

Publication number: CN115528834A
Application number: CN202210684996.7A
Authority: CN
Inventors: 刘益卯
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-06-15
Filing date: 2022-06-15
Publication date: 2022-12-27

Abstract

The invention discloses a self-starting permanent magnet synchronous motor and a rotor structure thereof, which comprise a rotating shaft and a rotor assembly sleeved on the rotating shaft, wherein the rotor assembly comprises a rotor core, end rings are arranged at two axial ends of the rotor core, a plurality of magnetic steels and a plurality of damping strips are embedded in the rotor core, the plurality of magnetic steels and the plurality of damping strips are annularly distributed by taking the axis of the rotating shaft as an axis respectively, and the damping strips are positioned at one side of the magnetic steels, which is close to the rotating shaft. The output power of the self-starting permanent magnet synchronous motor is improved through the invention, so that the use requirements of enterprises are met.

Description

Self-starting permanent magnet synchronous motor and rotor structure thereof

Technical Field

The invention relates to the technical field of motors, in particular to a self-starting permanent magnet synchronous motor and a rotor structure thereof.

Background

In recent years, the starting permanent magnet synchronous motor is more and more emphasized by people, compared with an asynchronous motor, the asynchronous motor has high operation stability, the efficiency and the power factor are higher than those of the asynchronous motor with the same power grade, the economic operation range is wide, and the asynchronous motor is expected to be replaced in a plurality of industrial application occasions. However, the output power of the existing self-starting permanent magnet synchronous motor is relatively low, and the use requirements of enterprises cannot be met.

Disclosure of Invention

The invention mainly aims to provide a self-starting permanent magnet synchronous motor and a rotor structure thereof, and aims to improve the output power of the self-starting permanent magnet synchronous motor and meet the use requirements of enterprises.

In order to achieve the above object, the present invention provides a rotor structure of a self-starting permanent magnet synchronous motor, including a rotating shaft and a rotor assembly sleeved on the rotating shaft, where the rotor assembly includes a rotor core, end rings are respectively disposed at two axial ends of the rotor core, a plurality of magnetic steels and a plurality of damping bars are embedded in the rotor core, the plurality of magnetic steels and the plurality of damping bars are annularly distributed with an axis of the rotating shaft as an axis, and the damping bars are located at one side of the magnetic steels close to the rotating shaft.

Optionally, the damping bar comprises a bar-shaped structure, and the bar-shaped length direction of the damping bar extends along the axial direction of the rotating shaft; a hollow part penetrating through the damping strip is arranged at the axis of the damping strip; the axial two ends of the damping strip penetrate through the end rings on the two sides respectively, and the damping strip is fixedly connected with the end rings.

Optionally, a first axial fan is installed on the rotating shaft, an induced draft lantern ring is sleeved on the outer side of the first axial fan, one end of the induced draft lantern ring is connected with the end ring, and the end of the damping strip is located on the inner side of the ring of the induced draft lantern ring.

Optionally, an insulating layer is disposed between the end ring and the magnetic steel.

Optionally, two sides of the magnetic steel are provided with magnetic isolation air grooves.

In order to achieve the above object, the present invention further provides a self-starting permanent magnet synchronous motor, which includes a stator assembly, where the stator assembly includes a stator core and a winding located on the stator core, and also includes the above rotor structure, and the stator assembly is sleeved on a rotor assembly of the rotor structure.

Optionally, the outside edge of stator core is equipped with a plurality of ventilation grooves, and is a plurality of the ventilation groove with the axis of pivot distributes as the axle center annular, just the ventilation groove runs through stator core's axial both ends.

Optionally, the magnetic steel comprises four magnetic steels, namely a first magnetic steel, a second magnetic steel, a third magnetic steel and a fourth magnetic steel; the first magnetic steel, the second magnetic steel, the third magnetic steel and the fourth magnetic steel are sequentially arranged along the circumferential direction, wherein the polarity of one side of the first magnetic steel and the second magnetic steel, which faces away from the rotating shaft, is opposite to the polarity of one side of the third magnetic steel and the fourth magnetic steel, which faces away from the rotating shaft; the windings on the stator core comprise star-delta sinusoidal windings.

Optionally, the magnetic steel comprises four magnetic steels, namely a first magnetic steel, a second magnetic steel, a third magnetic steel and a fourth magnetic steel; the first magnetic steel, the second magnetic steel, the third magnetic steel and the fourth magnetic steel are sequentially arranged along the circumferential direction, wherein the polarity of one side of the first magnetic steel and the third magnetic steel, which faces away from the rotating shaft, is opposite to the polarity of one side of the second magnetic steel and the fourth magnetic steel, which faces away from the rotating shaft; the windings on the stator core comprise single layer concentric windings.

Optionally, the fan further comprises a base, two sides of the rotating shaft are rotatably connected with the base through bearings, one end of the rotating shaft is exposed out of the base, and the other end of the rotating shaft is provided with a second fan; the rotor assembly and the stator assembly are located inside the housing.

Compared with the prior art, the invention has the beneficial effects that:

research shows that when the damping bars are positioned on one side of the magnetic steel far away from the rotating shaft, part of the magnetic force generated by the magnetic steel is leaked out of the space occupied by the damping bars, so that effective magnetic flux cannot be formed through the stator component, the air gap magnetic flux density of the self-starting permanent magnet synchronous motor is low, under the condition that other parameters are fixed, the output power of the motor is in a direct proportion relation with the air gap magnetic flux density, and when the air gap magnetic flux density is reduced, the output power of the motor is correspondingly reduced, which is the main reason that the output power of the self-starting permanent magnet synchronous motor is relatively low.

Based on the research, the damping strips are arranged on one side of the magnetic steel close to the rotating shaft, and the air gap flux density of the motor is improved by preventing a part of the magnetic force generated by the magnetic steel from being leaked out by the space occupied by the damping strips. Because the output power of the motor is in a direct proportion relation with the air gap flux density, when the air gap flux density is increased, the output power of the motor is correspondingly increased, and therefore the high-power-density self-starting permanent magnet synchronous motor is manufactured and meets the use requirements of enterprises.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic view of a rotor assembly according to an embodiment of a rotor structure of the present invention;

FIG. 2 is a schematic structural diagram of a rotor assembly according to an embodiment of the present invention;

FIG. 3 is a schematic view of an internal structure of a rotor assembly according to an embodiment of the rotor structure of the present invention;

FIG. 4 is a graph illustrating test results of an embodiment of a rotor structure according to the present invention;

FIG. 5 is a schematic structural diagram of a dual damping slot structure in an embodiment of a rotor structure according to the present invention;

fig. 6 is a schematic view for assisting understanding of the distance between the magnetic steel and the damping bars in an embodiment of the rotor structure of the present invention (fig. a is a single damping slot structure, and fig. b is a double damping slot structure);

FIG. 7 is a schematic structural view of an embodiment of a rotor structure according to the present invention;

fig. 8 is a schematic structural diagram of a stator core in an embodiment of a self-starting permanent magnet synchronous motor according to the present invention;

fig. 9 is a schematic structural diagram of rotor cores of a 2-pole motor and a 4-pole motor in an embodiment of the self-starting permanent magnet synchronous motor of the present invention (fig. a is the 2-pole motor, and fig. b is the 4-pole motor);

fig. 10 is a schematic diagram of the overall structure of a self-starting permanent magnet synchronous motor according to an embodiment of the present invention (the direction of the arrow in the drawing is the airflow direction).

The names of the components identified in the figures are as follows:

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the description is only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

The technical problem that the output power of the existing self-starting permanent magnet synchronous motor is relatively low and cannot meet the use requirements of enterprises is solved.

Research shows that when the damping bars are positioned on one side of the magnetic steel far away from the rotating shaft, part of the magnetic force generated by the magnetic steel is leaked out of the space occupied by the damping bars, so that effective magnetic flux cannot be formed through the stator component, and the air gap magnetic flux density of the self-starting permanent magnet synchronous motor is low. Under the condition that other parameters are fixed, the output power of the motor is in a direct proportion relation with the air gap flux density, and when the air gap flux density is reduced, the output power of the motor is correspondingly reduced, which is the main reason that the output power of the self-starting permanent magnet synchronous motor is relatively low.

Wherein, the specific inference process is as follows: according to the record of book "keep away and design of modern brushless dc permanent magnet motor" -leaf golden tiger edition-beijing scientific press-first edition of 8 months 2007-page 96: like a general electromagnetic synchronous motor, a brushless dc permanent magnet synchronous motor must also satisfy a certain relationship among physical parameters such as the main size, the power, the rotational speed, and the electromagnetic load of the motor, that is:

in the formula D _α Armature diameter (cm);

l _δ calculating a length (cm) for the armature core;

n _H the rated rotating speed (r/min) of the motor;

α _i to calculate the pole-arc coefficient, alpha _i ≈0.65；

k _φ Is the coefficient of the magnetic field waveform, k _φ ≈1；

k _w Is the winding coefficient;

A _S is a line load (A/cm);

B _δ is the air gap flux density (G) _S )；

P' is the output power (KW) of the motor;

from the above relational expression, it can be seen that the output power P' of the motor and the air gap flux density B are constant under the condition that other physical parameters are constant _δ In a proportional relationship, when the air gap flux density is increased, the output power of the motor is correspondingly increased, and vice versa.

Based on the above research findings, the present embodiment discloses a rotor structure of a self-starting permanent magnet synchronous motor, refer to fig. 1-3, including pivot 1 and the rotor subassembly of cover locating in pivot 1, the rotor subassembly includes rotor core 2, rotor core 2's axial both ends all are equipped with end links 3, rotor core 2 is last to be embedded with a plurality of magnet steel 4 and a plurality of damping strip 5, a plurality of magnet steel 4 and a plurality of damping strip 5 use the axis of pivot 1 respectively as axle center annular distribution, and damping strip 5 is located the one side that is close to pivot 1 of magnet steel 4.

In the embodiment, the damping strips 5 are arranged on one side, close to the rotating shaft 1, of the magnetic steel 4, and one part of the magnetic force generated by the magnetic steel 4 is prevented from being leaked out by the space occupied by the damping strips 5, so that the air gap flux density of the motor is improved. Because the output power of the motor is in a direct proportion relation with the air gap flux density, when the air gap flux density is increased, the output power of the motor is correspondingly increased, so that the use requirement of an enterprise is met.

It should be noted that the processes inferred from the above studies are all the intellectual crystals of the present inventors, and are also one of the inventions of the present invention. In evaluating the inventive process, the process inferred from the above studies should also be included in the scope of evaluation.

For further verifying the validity of this embodiment, choose two self-starting permanent magnet synchronous motors for use, wherein two self-starting permanent magnet synchronous motors's main difference lies in that damping strip 5 of motor 1 is located one side (the technical scheme of this embodiment) that is close to pivot 1 of magnet steel 4, and damping strip 5 of motor 2 is located one side of keeping away from pivot 1 of magnet steel 4, and other physical parameters are the same in addition, including magnet steel 4 thickness, stator and rotor iron core 2 length etc.. The running performance of the motor 1 and the motor 2 is calculated by adopting Ansoft Mamwell calculation software, and the test result is shown in the attached figure 4, wherein the graph (a) is a characteristic curve of output power and torque angle calculated by the motor 1, the maximum value is 4.36KW, the performance requirement of rated 1.5KW running can be met, and the standard GB/T22711-2019 is implemented. Fig. b is a characteristic curve of the output power and the torque angle calculated by the motor 2, the maximum value of which is 1.81KW, and which can satisfy the performance requirement of rated 0.75KW operation, and the execution standard GB/T22711-2019 is satisfied. Therefore, the running performance of the motor 1 adopting the technical scheme of the embodiment is obviously superior to that of the motor 2, and the maximum output power and the rated output power of the motor are obviously improved.

Specifically, the rotor core 2 is formed by overlapping a plurality of rotor punching sheets, and the rotor punching sheets are provided with a rotating shaft hole for installing the rotating shaft 1, a magnetic steel groove for installing the magnetic steel 4 and a damping groove for installing the damping strip. The rotor punching sheet is made of silicon steel.

As a priority of the above embodiment, referring to fig. 1 to 3, the damping bars 5 include a round bar type structure, and the round bar type length direction of the damping bars 5 is extended along the axial direction of the rotating shaft 1; the axis of the damping strip 5 is provided with a hollow part 501 penetrating through two axial ends of the damping strip; the two axial ends of the damping strip 5 respectively penetrate through the end rings 3 on the two sides, and the damping strip 5 is fixedly connected with the end rings 3. So set up, because from starting PMSM when the starting process is accomplished, tens K can rise in damping strip 5 temperature in a few seconds, for reducing the influence of temperature rise to magnet steel 4, this embodiment is through letting the air current through the interior well kenozooecium 501 that is located damping strip 5 in order to cool off damping strip 5 to reach the purpose that reduces damping strip 5 temperature rise. At the same time, the damping bars 5 are fixedly connected with the end ring 3 to form a starting cage of the rotor assembly, which helps the rotor assembly accelerate to a near synchronous speed when the motor is started.

Further, referring to fig. 7, a first axial fan 6 is installed on the rotating shaft 1, an air inducing lantern ring 7 is sleeved outside the first axial fan 6, one end of the air inducing lantern ring 7 is connected with the end ring 3, and the end of the damping bar 5 is located on the annular inner side of the air inducing lantern ring 7. With this arrangement, the first axial fan 6 is provided to generate an air flow, and the air flow is guided to the hollow portion 501 of the damping strip 5 by the air-inducing collar 7, so as to ensure the cooling of the damping strip 5.

As a preferable scheme of the above embodiment, as shown in FIG. 6 (a), the distance h from the damping bar 5 to the outer circle of the rotor ₀₂ ＝h _m +1.0 to 4.0 (mm), wherein h _m Is the thickness of the magnetic steel 4. With the arrangement, the distance between the magnetic steel 4 and the damping strip 5 is increased as far as possible under the condition that starting performance allows.

Further, as shown in fig. 5, when the self-starting permanent magnet synchronous motor is more than 10 poles, a double-damping-slot structure is adopted, that is, the annular structure formed by the damping strips 5 is provided with two circles and coaxially arranged, and two damping strips 5 located in the same radial direction of the rotating shaft 1 are provided. The arrangement is adopted, so that the starting torque is improved, and the pulling capacity of the motor is improved.

Specifically, when the double damping slot structure is adopted, the specific positional relationship is shown in fig. 6 (b), wherein b ₀₂ ＝b ₀₃ ＝0，b _r1 ＝b _r2 ，h ₀₃ ＝2～4(mm)。

As a preferred solution of the above embodiment, referring to fig. 3, an insulating layer 8 is disposed between the end ring 3 and the magnetic steel 4. With such an arrangement, it is considered that when the magnetic steel 4 and the end ring 3 are short-circuited, a large current may pass through the motor when the motor is started, and the heating and demagnetization may occur. In order to prevent this, an insulating layer 8 is provided between the magnetic steel 4 and the end ring 3.

As a preferable scheme of the above embodiment, referring to fig. 2, magnetic isolation air grooves 9 are provided on both sides of the magnetic steel 4. So set up, through setting up magnetism air pocket 9 to realize that the magnetic circuit of leakage magnetic field is smooth, the harmonic magnetic field weakens, and the leakage reactance reduces, has improved self-starting permanent magnet synchronous motor magnet steel 4's utilization ratio, has reduced the torque ripple, and has weakened the tooth's socket torque influence of magnet steel 4 to the stator.

The embodiment also discloses a self-starting permanent magnet synchronous motor, which, with reference to fig. 8-10, includes a stator assembly including a stator core 10 and a winding (not shown in the drawings) located on the stator core 10, and further includes the above-mentioned rotor structure, and the stator assembly is sleeved on the rotor assembly of the rotor structure. So set up, through with foretell rotor structure be applied to the self-starting permanent magnet synchronous motor in, utilize among the rotor structure to set up damping strip 5 in the one side of being close to pivot 1 of magnet steel 4, partly by the shared space of damping strip 5 in the magnetic force of avoiding magnet steel 4 to produce and leak to improve the air gap magnetic flux density of motor. Because the output power of the motor is in a direct proportion relation with the air gap flux density, when the air gap flux density is increased, the output power of the motor is correspondingly increased, and therefore the high-power-density self-starting permanent magnet synchronous motor is manufactured and meets the use requirements of enterprises.

The stator core 10 is formed by laminating a plurality of stator laminations, and the stator laminations are made of silicon steel.

As a preferable solution of the above embodiment, referring to fig. 8, a plurality of ventilation slots 11 are provided at an outer edge of the stator core 10, the plurality of ventilation slots 11 are annularly distributed with an axis of the rotating shaft 1 as an axis, and the ventilation slots 11 penetrate through two axial ends of the stator core 10. In this way, by providing the plurality of ventilation slots 11 on the stator core 10, when the airflow passes through the hollow portion 501 of the damping bar 5 and reaches the second end from the first end of the rotor structure, the airflow can be returned to the first end of the rotor structure through the ventilation slots 11 under the guiding action of the first axial fan 6, so that the airflow can circularly flow, and a closed-loop air path is formed. In the present embodiment, the ventilation grooves 11 have a semicircular structure.

As a preferred scheme of the above embodiment, as shown in fig. 9 (a), the magnetic connector includes four magnetic steels 4, which are a first magnetic steel, a second magnetic steel, a third magnetic steel, and a fourth magnetic steel; the first magnetic steel, the second magnetic steel, the third magnetic steel and the fourth magnetic steel are sequentially arranged along the circumferential direction, wherein the polarity of one side of the first magnetic steel and the second magnetic steel, which is back to the rotating shaft 1, is opposite to the polarity of one side of the third magnetic steel and the fourth magnetic steel, which is back to the rotating shaft 1; the windings on the stator core 10 comprise star-delta sinusoidal windings. So set up, through stipulating the polarity overall arrangement of magnet steel 4 in order to form self-starting permanent-magnet synchronous machine 2 utmost point motor, wherein, consider because the starting current of 2 utmost point motors is great, through adopting star-triangle sinusoidal winding to improve the winding coefficient, thereby reduce starting current.

As a preferable scheme of the above embodiment, as shown in fig. 9 (b), the magnetic steel structure includes four magnetic steels 4, which are a first magnetic steel, a second magnetic steel, a third magnetic steel, and a fourth magnetic steel; the first magnetic steel, the second magnetic steel, the third magnetic steel and the fourth magnetic steel are sequentially arranged along the circumferential direction, wherein the polarity of one side of the first magnetic steel and the third magnetic steel, which is back to the rotating shaft 1, is opposite to the polarity of one side of the second magnetic steel and the fourth magnetic steel, which is back to the rotating shaft 1; the windings on the stator core 10 comprise a single layer of concentric windings. With this arrangement, a polarity layout of the magnetic steel 4 is defined to form a self-starting permanent magnet synchronous motor 4-pole motor, wherein, considering that the starting current of the 4-pole motor is relatively small compared with the 2-pole motor, the requirement on the number of windings is relatively low, and therefore, a single-layer concentric winding can be selected.

As a preferable scheme of the above embodiment, referring to fig. 10, the air conditioner further includes a base 12, two sides of the rotating shaft 1 are rotatably connected to the base 12 through bearings 13, one end of the rotating shaft 1 is exposed out of the base 12, and the other end of the rotating shaft 1 is provided with a second fan 14; the rotor assembly and the stator assembly are located inside the housing 12. With such an arrangement, the second fan 14 is disposed at the other end of the rotating shaft 1, and the airflow generated by the second fan 14 directly acts on the base 12 itself, so as to cool the base 12, and the rotating shaft 1, the rotor structure and the stator structure inside the base 12.

It should be noted that other contents of the self-starting permanent magnet synchronous motor and the rotor structure thereof disclosed by the present invention are prior art, and are not described herein again.

In addition, it should be noted that if directional indications (such as upper, lower, left, right, front and rear \8230;) are involved in the embodiment of the present invention, the directional indications are only used for explaining the relative positional relationship, movement and the like between the components in a specific posture (as shown in the figure), and if the specific posture is changed, the directional indications are correspondingly changed.

Furthermore, it should be noted that the descriptions relating to "first", "second", etc. in the present invention are only used for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

The above are only alternative embodiments of the present invention, and not intended to limit the scope of the present invention, and all the applications of the present invention in other related fields are included in the scope of the present invention.

Claims

1. A rotor structure characterized by: locate including pivot and cover epaxial rotor subassembly, the rotor subassembly includes rotor core, rotor core's axial both ends all are equipped with the end links, rotor core is last to be embedded to have a plurality of magnet steel and a plurality of damping strip, and is a plurality of magnet steel and a plurality of damping strip use respectively the axis of pivot distributes as the axle center annular, just damping strip is located being close to of magnet steel one side of pivot.

2. The rotor structure of claim 1, wherein: the damping strip comprises a rod-shaped structure, and the length direction of the rod shape of the damping strip extends along the axial direction of the rotating shaft; a hollow part penetrating through the damping strip is arranged at the axis of the damping strip; the axial two ends of the damping strip penetrate through the end rings on the two sides respectively, and the damping strip is fixedly connected with the end rings.

3. The rotor structure of claim 2, wherein: the damping device is characterized in that a first axial flow fan is installed on the rotating shaft, an air inducing lantern ring is sleeved on the outer side of the first axial flow fan, one end of the air inducing lantern ring is connected with the end ring, and the end part of the damping strip is located on the inner side of the ring of the air inducing lantern ring.

4. The rotor structure of claim 1, wherein: an insulating layer is arranged between the end ring and the magnetic steel.

5. The rotor structure of claim 1, wherein: and magnetic isolation air grooves are formed in two sides of the magnetic steel.

6. The utility model provides a from starting PMSM, includes stator module, stator module includes stator core and is located winding on the stator core, its characterized in that: a rotor structure as claimed in any one of claims 1 to 6, further comprising a stator assembly sleeved on the rotor assembly.

7. The self-starting permanent magnet synchronous motor according to claim 6, characterized in that: stator core's outside edge is equipped with a plurality of ventilation grooves, and is a plurality of the ventilation groove with the axis of pivot distributes as the axle center annular, just the ventilation groove runs through stator core's axial both ends.

8. The self-starting permanent magnet synchronous motor according to claim 6, characterized in that: the magnetic steel comprises four magnetic steels, namely a first magnetic steel, a second magnetic steel, a third magnetic steel and a fourth magnetic steel; the first magnetic steel, the second magnetic steel, the third magnetic steel and the fourth magnetic steel are sequentially arranged along the circumferential direction, wherein the polarity of one side of the first magnetic steel and the second magnetic steel, which is back to the rotating shaft, is opposite to the polarity of one side of the third magnetic steel and the fourth magnetic steel, which is back to the rotating shaft; the windings on the stator core comprise star-delta sinusoidal windings.

9. The self-starting permanent magnet synchronous motor according to claim 6, characterized in that: the magnetic steel comprises four magnetic steels, namely a first magnetic steel, a second magnetic steel, a third magnetic steel and a fourth magnetic steel; the first magnetic steel, the second magnetic steel, the third magnetic steel and the fourth magnetic steel are sequentially arranged along the circumferential direction, wherein the polarity of one side of the first magnetic steel and the third magnetic steel, which is back to the rotating shaft, is opposite to the polarity of one side of the second magnetic steel and the fourth magnetic steel, which is back to the rotating shaft; the windings on the stator core comprise single layer concentric windings.

10. The self-starting permanent magnet synchronous motor according to claim 6, characterized in that: the fan comprises a base, wherein two sides of the rotating shaft are rotatably connected with the base through bearings, one end of the rotating shaft is exposed out of the base, and the other end of the rotating shaft is provided with a second fan; the rotor assembly and the stator assembly are located inside the housing.