KR102120361B1 - A rotor having a conductor bar of a different length and a synchronous motor comprising the same - Google Patents

Abstract

The present invention relates to a rotor having a conductor bar having a different length and a synchronous type motor including the same to suppress a vibration occurrence during driving. According to the present invention, the rotor comprises: a rotor core having a rotation shaft inserted into a central portion thereof; a plurality of permanent magnets inserted into the rotor core of a circumference of the rotation shaft to form rotor magnetic poles of an N pole and an S pole; and a plurality of conductor bars inserted into the rotor core with a length corresponding to a distance between the plurality of permanent magnets and an outer periphery of the rotor core. According to the present invention, the synchronous type motor has the conductor bar having a different length to reduce a harmonic component of a counter electromotive force and allow the counter electromotive force to be implemented to be close to a sinusoidal wave so as to reduce distortion of an input current, thereby suppressing the vibration occurrence.

Description

A rotor having a conductor bar of a different length and a synchronous motor comprising the same}

The present invention relates to a synchronous motor, and more particularly, to a rotor having a conductor bar of different length capable of suppressing the generation of vibrations according to harmonic components of back EMF and a synchronous motor including the same.

Typically, a motor (motor, or electric motor) converts electrical energy into mechanical energy to generate a rotational force, and is widely used for home and industrial use. These motors can be broadly classified into an AC motor and a DC motor.

The DC motor is driven by a DC power supply, and is a motor that obtains a desired output by changing the input voltage. It is relatively easy to adjust speed and is used for driving vehicles, elevators, and the like. The DC motor can be divided into a brush DC motor and a brushless DC motor. The brushless DC motor has a feature that there is no mechanical contact part between the brush DC motor and the brush commutator, and accordingly, it is possible to achieve high performance of the device, reduction in light weight, and long life. In addition, the brushless DC motor has a structure in which a winding is wound around the stator and a permanent magnet is embedded in the rotor. These brushless DC motors are widely used in various devices according to the development of semiconductor technology and components and materials.

The AC motor is driven by AC power and is one of the most widely used motors around life. The AC motor basically consists of an external stator and an internal rotor, and when AC current is supplied to the stator winding, the electric field is converted by electromagnetic induction and induced by the electric field rotating in the rotor. It is a motor that generates electric current and generates rotational force on the rotating shaft in the rotor due to torque.

These AC motors are largely classified into a single-phase type and a three-phase type, and can be further classified into an induction motor, a synchronous motor, and a commutator motor according to the type of rotor.

Synchronous motors, such as LSPM (Line Start Permanent Magnet) motors (also referred to as'single-phase induction synchronous motors'), are a type of AC motor that applies only the advantages of single-phase induction motors and synchronous motors.

In such a synchronous motor, the rotor starts to rotate and is started by the torque generated by the interaction of the secondary current generated by the voltage induced on the conductor bar of the rotor and the magnetic flux generated by the stator winding. At rated operation, the motor operates at the speed of the stator's magnetic field in synchronization with the magnetic flux of the permanent magnet installed on the rotor and the magnetic flux generated by the stator. That is, when a current is applied to the stator winding, the rotor rotates by the interaction of the rotating magnetic flux generated by the structure of the stator and the induced current generated in the conductor bar of the rotor. And when the rotational speed reaches the synchronous speed, the torque caused by the permanent magnet and the reluctance torque due to the structure of the rotor are generated, and the rotor rotates.

The rotor of the synchronous motor has a cylindrical rotor core and a plurality of conductor bars are inserted around the edges of the rotor core, and a plurality of permanent magnets are inserted and installed inside the conductor bar.

Due to this, the synchronous motor generates harmonics in the back EMF depending on the number and shape of slots and permanent magnets, and these harmonic components generate harmonic components of the current and consequently cause vibration noise.

Registered Patent No. 10-1209631 (Registration on December 12, 2012)

Accordingly, an object of the present invention is to provide a rotor having a conductor bar having a different length to suppress vibration generation by reducing a harmonic component of back EMF and a synchronous motor including the same.

Another object of the present invention is to provide a synchronous motor including a rotor having a conductor bar of different lengths capable of suppressing the occurrence of vibration and reducing the distortion of input current by implementing a back electromotive force close to a sinusoidal wave.

In order to achieve the above object, the present invention is a rotor for a synchronous motor that is rotatably installed by being inserted into a rotor insertion hole of a stator, a rotor iron core having a rotating shaft inserted in a central portion; A plurality of permanent magnets inserted into the rotor core around the rotation axis to form rotor poles of the N and S poles; And a plurality of conductor bars inserted into the rotor core at a length corresponding to the distance between the plurality of permanent magnets and the outer periphery of the rotor core.

In the rotor core, a rotational shaft insertion hole in which the rotational shaft is inserted is formed in a central portion, and a plurality of permanent magnet insertion holes in which a plurality of permanent magnets are inserted around the rotational shaft insertion hole are formed, and the plurality of The conductor bar insertion hole into which the plurality of conductor bars are inserted may be formed to have a length corresponding to a gap between the permanent magnet insertion hole and the outer periphery of the rotor core.

The plurality of permanent magnets, a plurality of first and second permanent magnets respectively disposed on both sides of the rotary shaft insertion hole to form an S pole; And a plurality of third and fourth permanent magnets respectively disposed in a direction perpendicular to the plurality of first and second permanent magnets around the insertion hole of the rotation shaft to form an N pole.

Each of the first to fourth permanent magnets may include a first partial permanent magnet and a second partial permanent magnet arranged in a V shape so as to form an obtuse angle around the rotation axis.

The plurality of conductor bars are disposed radially around the rotation axis.

The lengths of the plurality of conductor bars increase as they move toward the neighbors from both ends of the first and second partial permanent magnets.

The width of the plurality of conductor bars decreases toward the center of the rotating shaft from the outer core of the rotor.

And the present invention is the rotor; And a stator in which a rotor insertion hole in which the rotor is inserted is formed at a central portion, and a winding is wound on an inner circumferential surface of the rotor insertion hole.

According to the present invention, since the conductor bars having different lengths corresponding to the distance between the outer periphery of the permanent magnet and the rotor core have a structure arranged in the rotor core, it is possible to suppress the occurrence of vibration by reducing the harmonic component of the back EMF.

In addition, in the synchronous motor according to the present invention, since the back electromotive force is implemented close to the sinusoidal wave, distortion of the input current is reduced and vibration can be suppressed.

1 is a plan view showing a rotor for a synchronous motor having a conductor bar having a different length according to an embodiment of the present invention.
FIG. 2 is a plan view showing a synchronous motor including the rotor of FIG. 1.
3 is a plan view showing a synchronous motor according to a comparative example.
4 and 5 are diagrams showing the results of finite element analysis of a synchronous motor according to a comparative example.
6 and 7 are diagrams showing finite enzyme analysis results of a synchronous motor according to an embodiment.
8 is a graph showing the results of back EMF analysis of a synchronous motor according to Comparative Examples and Examples.
9 is a graph showing the results of harmonic analysis of back EMF of a synchronous motor according to Comparative Examples and Examples.
10 is a graph showing an input current analysis result of a synchronous motor according to a comparative example and an embodiment.
11 is a graph showing the results of harmonic analysis of the input current of a synchronous motor according to Comparative Examples and Examples.

It should be noted that in the following description, only parts necessary for understanding the embodiments of the present invention are described, and descriptions of other parts will be omitted without detracting from the gist of the present invention.

The terms or words used in the present specification and claims described below should not be construed as being limited to ordinary or lexical meanings, and the inventor is appropriate as a concept of terms to describe his or her invention in the best way. It should be interpreted as a meaning and a concept consistent with the technical idea of the present invention based on the principle that it can be defined as such. Therefore, the configuration shown in the embodiments and drawings described in this specification is only a preferred embodiment of the present invention, and does not represent all of the technical spirit of the present invention, and various equivalents that can replace them at the time of this application It should be understood that there may be and variations.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a plan view showing a rotor for a synchronous motor having a conductor bar having a different length according to an embodiment of the present invention. FIG. 2 is a plan view showing a synchronous motor including the rotor of FIG. 1.

1 and 2, the synchronous motor 100 according to the present embodiment includes a rotor 20 and a stator 10 in which the rotor 20 is rotatably inserted and installed. In the stator 10, a rotor insertion hole 18 is formed in a central portion, and a winding 16 is wound on an inner circumferential surface of the rotor insertion hole 18. And the rotor 20 is inserted into the rotor insertion hole 18 of the stator 10 and is rotatably installed.

The stator 10 includes a stator iron core 11 in which a rotor insertion hole 18 is formed, and a winding 16 wound along the inner circumferential surface of the rotor insertion hole 18 of the stator iron core 11. At this time, the inner diameter of the rotor insertion hole 18 is formed larger than the outer diameter of the rotor 20, the difference between the inner diameter of the rotor insertion hole 18 and the outer diameter of the rotor 20 forms a void.

The stator iron core 11 may be formed by stacking a plurality of stator iron plates 12 of the same shape in the axial direction. The stator iron core 11 is formed with a rotor insertion hole 18 into which the rotor 20 is inserted and positioned. The stator iron core 11 is formed with a plurality of teeth 14 at regular intervals along the inner circumferential surface. The plurality of teeth 14 protrude from the inner circumferential surface of the stator iron core 11 toward the central axis of the stator iron core 11 and are disposed close to the outer circumferential surface of the rotor 20 which is inserted into and installed in the rotor insertion hole 18. do. At this time, a silicon iron plate may be used as the stator iron plate 12. The inside of the virtual surface formed by the end of the tooth 14 inside the stator iron core 11 forms the rotor insertion hole 18.

In addition, the windings 16 are wound on each of the plurality of teeth 14, and thus, when AC power is applied, a rotating magnetic flux is generated due to the structure of the stator 10.

On the other hand, although not shown, the rotating shaft 30 is rotatably installed via a bearing in a casing or shell forming a case of the synchronous motor 100.

The rotor 20 is a rotor of the synchronous motor 100 inserted into the rotor insertion hole 18 of the stator 10 and rotatably installed, the rotor iron core 21 and a plurality of permanent magnets ( 22), and a plurality of conductor bars 23. The rotor iron core 21 is provided with a rotating shaft 30 inserted in a central portion. The plurality of permanent magnets 22 are inserted into the rotor iron core 21 around the rotating shaft 30 to form rotor poles of the N and S poles. In addition, the plurality of conductor bars 23 are inserted into the rotor iron core 21 in a length corresponding to the distance between the plurality of permanent magnets 22 and the outer periphery of the rotor iron core 21.

The reason for forming a plurality of conductor bars 23 having a length corresponding to the gap between the outer periphery of the plurality of permanent magnets 22 and the rotor core 21 is to suppress the occurrence of vibration by reducing harmonic components of back EMF. to be. Therefore, in the synchronous motor 100 according to the present embodiment, since the counter electromotive force is implemented close to the sinusoidal wave, distortion of the input current is reduced and vibration can be suppressed.

The rotor 20 according to this embodiment will be described in detail as follows.

As described above, the rotor 20 includes a rotor iron core 21, a plurality of permanent magnets 22, and a plurality of conductor bars 23.

The rotor iron core 21 is formed by laminating a plurality of rotor iron plates 24 of the same shape in the axial direction. The rotor iron core 21 is formed with a rotation shaft insertion hole 25 into which the rotation shaft 30 is inserted in the central portion. The rotor iron core 21 has a plurality of permanent magnet insertion holes 26 formed outside the rotation shaft insertion holes 25. In addition, the rotor iron core 21 is formed with a plurality of conductor bar insertion holes 27 around the outer edge of the plurality of permanent magnet insertion holes 26.

At this time, a silicon steel plate may be used as the rotor iron plate 24. The rotation shaft insertion hole 25, the permanent magnet insertion hole 26, and the conductor bar insertion hole 27 may be formed in a vertical direction with respect to the upper surface of the rotor iron core 21.

In this embodiment, eight permanent magnet insertion holes 26 in which a permanent magnet 22 having a rectangular cross section is installed with respect to the axial direction of the rotation shaft insertion hole 25 on the outer side around the rotation shaft insertion hole 25 are the rotors. Although an example formed in the iron core 21 is disclosed, it is not limited to this. At this time, the eight permanent magnet insertion holes 26 may be formed in four places around the rotational shaft insertion hole 25 in an English letter V shape in pairs of two. The angle formed by the four permanent magnet insertion holes 41, 42, 43, 44 arranged in a V shape is an obtuse angle, and between the four permanent magnet insertion holes 41, 42, 43, 44 arranged in a neighboring V shape. The angle formed may be an acute angle.

That is, the plurality of permanent magnet insertion holes 26 are disposed on both sides around the rotation shaft insertion hole 25, and a plurality of first and second permanent magnets 51 and 52 into which S poles are formed are inserted. The first and second permanent magnet insertion holes 41 and 42 and the plurality of first and second permanent magnet insertion holes 41 and 42 are disposed in the direction perpendicular to the plurality of first and second permanent magnet insertion holes 41 and N poles, respectively. And a plurality of third and fourth permanent magnet insertion holes 43 and 44 into which a plurality of third and fourth permanent magnets 53 and 54 are formed.

The plurality of first to fourth permanent magnet insertion holes 41, 42, 43, and 44, respectively, the first and second partial permanent magnet insertion holes formed in a V shape to form an obtuse angle around the rotation shaft insertion hole 25 ( 46,47). For this reason, the first and second partial permanent magnets 56 and 57 respectively inserted in the first and second partial permanent magnet insertion holes 46 and 47 are arranged to form an obtuse angle with each other.

Then, toward the rotation shaft insertion hole 25, the first and second partial permanent magnet insertion holes 46 and 27 adjacent to each other are formed to form an acute angle with each other. Accordingly, the first and second partial permanent magnets 56 and 57 inserted into the first and second partial permanent magnet insertion holes 46 and 27 adjacent to each other are disposed to form an acute angle with each other.

The plurality of permanent magnets 22 are respectively inserted into the plurality of permanent magnet insertion holes 26 of the rotor core 21 to form rotor poles of the N and S poles. At this time, the plurality of permanent magnets 22 generate torque by interaction with magnetic flux generated in the winding 16. A rare earth magnet may be used as the permanent magnet 22.

The plurality of permanent magnets 22 are inserted into the first and second permanent magnet insertion holes 41 and 42 to form first and second permanent magnets 51 and 52, and third and fourth permanent magnets. It includes third and fourth permanent magnets 53 and 54 that are inserted into the magnet insertion holes 43 and 44 to form the N pole.

The plurality of first to fourth permanent magnets 51, 52, 53 and 54 are respectively inserted into the first and second inclined permanent magnet insertion holes 46 and 47, respectively, and the first and second partial permanent magnets 56 ,57).

In this embodiment, the conductor bar 23 and the conductor bar insertion hole 27 are formed as follows in order to reduce the harmonic component before the back EMF.

The plurality of conductor bars 23 are inserted into the rotor iron core 21 at a length corresponding to the distance between the plurality of permanent magnets 22 and the outer periphery of the rotor iron core 21. That is, since the distance between the outer periphery of the rotor iron core 21 and the permanent magnet 22 around the rotating shaft 30 occurs, a plurality of conductors formed between the outer periphery of the permanent magnet 22 and the rotor iron core 21 The lengths of the bars 23 are different from each other.

The plurality of conductor bars 23 may be disposed radially around the rotation axis. The plurality of conductor bars 23 are lengthened toward the neighboring sides at both ends of the first and second partial permanent magnets. And the width of the plurality of conductor bars 23 decreases toward the center of the rotating shaft 30 from the outer side of the rotor iron core 21.

The plurality of conductor bars 27 includes a plurality of first and second conductor bars 27a and 27b, and a plurality of third and fourth conductor bars 27c and 27d. The plurality of first and second conductor bars 27a and 27b are formed on the side where the plurality of first and second permanent magnets 51 and 52 are formed. The plurality of third and fourth conductor bars 27c and 27d are formed on the side where the plurality of third and fourth permanent magnets 53 and 54 are formed.

The plurality of first to fourth conductor bars 27a, 27b, 27c, and 27d are formed to be shorter in length toward the edge from the center of the V-shaped first to fourth permanent magnets 51, 52, 53, and 54. .

In addition, a plurality of first to fourth conductor bar insertion holes 23a, 23b, 23c, and 23d into which the plurality of first to fourth conductor bars 27a, 27b, 27c, and 27d are respectively inserted are the rotor cores 22 Is formed on.

In the synchronous motor 100 according to the present exemplary embodiment, by providing a conductor bar 23 having a different length, harmonic components of back EMF are reduced and back EMF is implemented close to a sinusoidal wave to reduce distortion of input current and vibrate. The suppression of the occurrence was confirmed through a finite element method (FEM), back EMF analysis, input current analysis, and current harmonic analysis, compared to the synchronous motor 200 of the comparative example shown in FIG. 3. 8 to 11, "Old" represents a synchronous motor according to a comparative example, and "New" represents a synchronous motor according to an embodiment.

3 is a plan view showing a synchronous motor according to a comparative example.

Referring to Figure 3, the synchronous motor 200 according to the comparative example, except that a plurality of conductor bars of a certain size having a circular cross-section around the edge of the rotor core is inserted, the synchronous motor ( It has the same structure as 100) in FIG. 2.

LSPM motors were used as synchronous motors according to Examples and Comparative Examples. Synchronous motors according to Examples and Comparative Examples include 4 poles, 36 slots, and 44 conductor bars.

4 and 5 are diagrams showing the results of finite element analysis of a synchronous motor according to a comparative example. 6 and 7 are diagrams showing finite enzyme analysis results of a synchronous motor according to an embodiment.

4 and 5 show the magnetic flux distribution of the synchronous motor according to the comparative example. 6 and 7 show the magnetic flux distribution of the synchronous motor according to the embodiment.

4 to 7, it can be seen that the magnetic flux distribution of the synchronous motor according to the embodiment is uniformly distributed compared to the magnetic flux distribution of the synchronous motor according to the comparative example.

8 is a graph showing the results of back EMF analysis of a synchronous motor according to Comparative Examples and Examples.

Referring to FIG. 8, in the case of the synchronous motor according to the comparative example, it can be seen that the ripple component due to the slot is high.

On the other hand, in the case of the synchronous motor according to the embodiment, it can be seen that when compared with the synchronous motor according to the comparative example, the ripple component is small.

The results of the back EMF analysis of FIG. 8 are confirmed through harmonic analysis as shown in FIG. 9. 9 is a graph showing the results of harmonic analysis of the back EMF of the synchronous motor according to the comparative example and the embodiment.

Referring to FIG. 9, in the synchronous motor according to the embodiment, although the fundamental EMF is reduced, it can be seen that the 3rd harmonic and the 17th harmonic are significantly reduced.

10 is a graph showing an input current analysis result of a synchronous motor according to a comparative example and an embodiment. 11 is a graph showing the results of harmonic analysis of the input current of a synchronous motor according to Comparative Examples and Examples.

10 and 11, in the synchronous motor according to the embodiment, as can be seen from the input current analysis result and the harmonic analysis result of the input current, 5 harmonics, 7 harmonics, and 17 harmonics components of the current harmonic are pronounced. You can see that it has been reduced.

In this way, the synchronous motor according to the embodiment has a conductor bar having a different length when compared with the synchronous motor according to the comparative example, thereby reducing harmonic components of back EMF and implementing back EMF close to sinusoidal distortion. It is judged that the vibration is reduced and suppressed.

On the other hand, the embodiments disclosed in the specification and the drawings are merely presented as specific examples to help understanding, and are not intended to limit the scope of the present invention. It is obvious to those skilled in the art to which the present invention pertains that other modifications based on the technical spirit of the present invention can be implemented in addition to the embodiments disclosed herein.

10: stator 11: stator iron core
12: stator iron plate 14: Tooth
16: Winding 18: Rotor insertion hole
20: rotor 21: iron core of the rotor
22: permanent magnet 23: conductor bar
23a: 1st conductor bar 23b: 2nd conductor bar
23c: 3rd conductor bar 23d: 4th conductor bar
24: rotor plate 25: rotation shaft insertion hole
26: permanent magnet insertion hole 27: conductor bar insertion hole
27a: 1st conductor bar insertion hole 27b: 2nd conductor bar insertion hole
27c: 3rd conductor bar insertion hole 27d: 4th conductor bar insertion hole
30: rotating shaft 41: first permanent magnet insertion hole
42: second permanent magnet insertion hole 43: third permanent magnet insertion hole
44: fourth permanent magnet insertion hole 46: first part permanent magnet insertion hole
47: second part permanent magnet insertion hole 51: first permanent magnet
52: second permanent magnet 53: third permanent magnet
54: fourth permanent magnet 56: first part permanent magnet
57: second part permanent magnet 100: synchronous motor

Claims (12)

A rotor for a synchronous motor that is inserted into the rotor insertion hole of the stator and is rotatably installed.
A rotor iron core in which a rotation axis is inserted in a central portion;
A plurality of permanent magnets inserted into the rotor core around the rotation axis to form rotor poles of the N and S poles; And
A plurality of conductor bars that are inserted into the rotor core with a length corresponding to the distance between the plurality of permanent magnets and the outer periphery of the rotor, and decrease in width toward the center of the rotation axis from the outer periphery of the rotor;
Rotor for a synchronous motor, characterized in that it comprises a. According to claim 1, The rotor core,
A rotating shaft insertion hole in which the rotation shaft is inserted is formed in a central portion, and a plurality of permanent magnet insertion holes in which a plurality of permanent magnets are inserted are formed around the rotation shaft insertion hole, and the plurality of permanent magnet insertion holes and the A rotor for a synchronous motor, characterized in that the conductor bar insertion hole into which the plurality of conductor bars are inserted is formed with a length corresponding to the distance between the outer edges of the rotor core. According to claim 2, The plurality of permanent magnets,
A plurality of first and second permanent magnets respectively disposed on both sides of the rotary shaft insertion hole to form an S pole; And
A plurality of third and fourth permanent magnets each disposed in a direction perpendicular to the plurality of first and second permanent magnets around the insertion hole of the rotation shaft to form an N pole;
Rotor for a synchronous motor, characterized in that it comprises a. According to claim 3, Each of the first to fourth permanent magnets,
And a first partial permanent magnet and a second partial permanent magnet arranged in a V-shape to form an obtuse angle around the rotation axis. The method of claim 4,
The plurality of conductor bars are a rotor for a synchronous motor, characterized in that arranged radially around the rotation axis. The method of claim 5, wherein the plurality of conductor bars,
A rotor for a synchronous motor, characterized in that the length of the first and second partial permanent magnets increases from each end toward the neighboring side. delete With the rotor;
Includes a stator in which a rotor insertion hole in which the rotor is inserted is formed at a central portion, and a winding is wound on an inner circumferential surface of the rotor insertion hole.
The rotor,
A rotor iron core in which a rotation axis is inserted in a central portion;
A plurality of permanent magnets inserted into the rotor core around the rotation axis to form rotor poles of the N and S poles; And
A plurality of conductor bars that are inserted into the rotor core with a length corresponding to the distance between the plurality of permanent magnets and the outer periphery of the rotor, and decrease in width toward the center of the rotation axis from the outer periphery of the rotor;
Synchronous motor comprising a. According to claim 8,
The plurality of permanent magnets,
A plurality of first and second permanent magnets respectively disposed on both sides of the rotation axis to form an S pole; And
It includes; a plurality of third and fourth permanent magnets respectively disposed in a direction perpendicular to the plurality of first and second permanent magnets around the rotation axis to form an N pole;
Each of the plurality of first to fourth permanent magnets,
And a first partial permanent magnet and a second partial permanent magnet arranged in a V-shape to form an obtuse angle around the rotation axis. The method of claim 9,
The plurality of conductor bars are synchronous motors, characterized in that arranged radially around the rotation axis. The method of claim 10, wherein the plurality of conductor bars,
A synchronous motor characterized in that the length of the first and second partial permanent magnets increases from each end toward the neighboring side. delete

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