A motor based on rotor round edge design and an electrical appliance using the motor

Abstract

The present invention provides a motor based on a rotor round edge design and an electrical appliance using the motor, which relates to the technical field of motors and aims to solve the problems of generating a large number of harmonics, high motor noise and low motor efficiency. The rotor round edge of the motor includes a first scattered point, a second scattered point, a third scattered point, a fourth scattered point and a fifth scattered point arranged in sequence, and the second scattered point is located on the bisector of a magnetic steel slot passing through the center of a rotor assembly; the lateral spacings of the first scattered point, the second scattered point, the third scattered point, the fourth scattered point and the fifth scattered point are all equal and recorded as ΔL; with the stator tooth round edge of the stator tooth portion as a reference, air gaps Δδ1, Δδ, Δδ1, Δδ2 and Δδ3 are formed between the rotor round edge and the stator tooth round edge at each scattered point, respectively, and Δδ is the minimum air gap; wherein Δδ1=Δδ / cosθ, Δδ2=Δδ / cos(θ+Δθ), Δδ3=Δδ / (θ+2Δθ), and θ and Δθ cooperate to make the air gap magnetic field tend to be sinusoidal. The electrical appliance adopts the above motor, which can effectively reduce back electromotive force harmonics, reduce motor iron loss and improve motor efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of motors, in particular to a motor based on a rotor round edge design and an electrical appliance using the motor. Background Art

[0002] Motor noise mainly comes from electromagnetic vibration. At present, the air gap between the stator and rotor of the motor is mostly evenly distributed. There are a lot of harmonics in the uniform air gap magnetic field, which also makes the motor iron loss and motor noise more serious, affecting the motor performance. In order to improve the air gap magnetic field, an uneven air gap is often designed, such as slotting the stator tooth end, uneven magnetic steel design, stator winding distribution, etc.

[0003] The present application designs the motor in another form to improve the motor back-EMF waveform, reduce the motor back-EMF harmonics, reduce the motor iron loss, and improve the motor efficiency. Summary of the invention

[0004] The purpose of the present invention is to design a motor based on a rotor round edge design and an electrical appliance using the motor, which can effectively reduce back electromotive force harmonics, reduce motor iron loss, and improve motor efficiency.

[0005] The present invention is achieved through the following technical solutions:

[0006] The present invention provides a motor based on a rotor circular edge design, comprising a rotor assembly and a stator assembly, wherein the rotor assembly comprises magnetic steel slots spaced circumferentially and magnetic steels installed in the magnetic steel slots, wherein the length of the magnetic steels is L; the stator assembly comprises stator teeth spaced circumferentially; the outer circle of the rotor assembly comprises a plurality of rotor circular edges, wherein the rotor circular edges comprise first scattered points, second scattered points, third scattered points, fourth scattered points and fifth scattered points arranged in sequence along the circumferential direction, wherein the second scattered points are located on the bisector of the magnetic steel slots passing through the center of the rotor assembly; and from the second scattered points along the tangent direction of the rotor circular edge, the first scattered points, The lateral spacings of the second scattered points, the third scattered points, the fourth scattered points and the fifth scattered points are all equal, and the lateral spacing between adjacent scattered points is recorded as ΔL; taking the stator tooth circular edge of the stator tooth portion as a reference, air gaps Δδ1, Δδ, Δδ1, Δδ2, Δδ3 are formed between the rotor circular edge and the stator tooth circular edge at the first scattered points, the second scattered points, the third scattered points, the fourth scattered points and the fifth scattered points, respectively, and Δδ is the minimum air gap; wherein, Δδ1=Δδ / cosθ, Δδ2=Δδ / cos(θ+Δθ), Δδ3=Δδ / (θ+2Δθ), and θ and Δθ are angles for making the air gap magnetic field tend to be sinusoidally set.

[0007] When the above-mentioned setting structure is adopted, this scheme is different from the prior art in obtaining a form of uneven air gap. This scheme is based on the rotor round edge design. Through the analysis of the stator and rotor air gaps, a motor based on the rotor round edge design is obtained. In order to make the magnetic field distribution in the air gap as close to the sine wave as possible, the rotor round edge is designed based on the minimum air gap Δδ, the magnetic steel length L, and the stator tooth round edge as the design basis to obtain an uneven air gap. Taking the second scattered point as the reference, move ΔL horizontally to the left and right along the tangential direction passing through it to obtain the first scattered point of the air gap Δδ1, the third scattered point of the air gap Δδ1, the fourth scattered point of Δδ2, and the fifth scattered point of the air gap Δδ3, so that the rotor round edge passes through these scattered points, which can effectively reduce the back electromotive force harmonics, reduce the motor iron loss, and improve the motor efficiency.

[0008] In order to better realize the present invention, the following setting structure is particularly adopted: the air gap relationship satisfies: Δδ<Δδ1<Δδ2<Δδ3.

[0009] In order to better implement the present invention, the following configuration is particularly adopted: ΔL≤1 / 6L.

[0010] To further better implement the present invention, the following configuration is particularly adopted: when ΔL=1 / 6L, 0.7<θ / Δθ<1.5.

[0011] In order to better implement the present invention, the following configuration is particularly adopted: when ΔL=1 / 6L, θ and Δθ satisfy: 13°<θ<17°, 14°<Δθ<16°.

[0012] In order to further better realize the present invention, the following setting structure is particularly adopted: the rotor circular edge includes a first circular edge, a second circular edge and a third circular edge connected in sequence; the first scattered point, the second scattered point and the third scattered point are on the first circular edge, and the first scattered point and the third scattered point are the endpoints of the first circular edge; the third scattered point, the fourth scattered point and the fifth scattered point are on the second circular edge, and the third scattered point and the fifth scattered point are the endpoints of the second circular edge; the third circular edge is an arc segment passing through the fifth scattered point, with the center of the rotor assembly as the center of the circle and the distance between the fifth scattered point and the center of the rotor assembly as the radius, and the fifth scattered point is the endpoint of the third circular edge.

[0013] When the above-mentioned setting structure is adopted, a segmented circular edge design is adopted to obtain an uneven air gap, so as to improve the air gap magnetic field distribution (close to sine), reduce the back electromotive force distortion rate, reduce the motor noise, reduce the motor iron loss, and thus improve the motor efficiency.

[0014] To further better realize the present invention, the following configuration is particularly adopted: all the circular edges of the rotor are sequentially connected end to end to form a complete outer circle.

[0015] In order to further better implement the present invention, the following setting structure is particularly adopted: the rotor circular edge also includes a fourth circular edge, the head end point of the fourth circular edge is the fifth scattered point, and the tail end point of the fourth circular edge is co-point with the first scattered point of the head end of another connected section of the rotor circular edge.

[0016] In order to better realize the present invention, the following setting structure is particularly adopted: the outer circle of the rotor assembly includes a sixth scattered point, at which an air gap Δδ2 is formed between the circular edge of the rotor and the circular edge of the stator tooth, and the sixth scattered point is located on the fourth circular edge.

[0017] When the above-mentioned setting structure is adopted, the rotor assembly adopts a segmented circular edge design to obtain an uneven air gap with the stator teeth, which improves the air gap magnetic field distribution (close to sinusoidal), reduces the back electromotive force distortion rate, reduces motor noise, reduces motor iron loss, and thus improves motor efficiency.

[0018] In order to further better realize the present invention, the following configuration structure is particularly adopted: the rotor core of the rotor assembly is provided with magnetic flux sorting grooves.

[0019] When the above-mentioned setting structure is adopted, a magnetic flux sorting groove is set in the rotor. The magnetic flux sorting groove can standardize the air gap magnetic circuit, make the air gap magnetic circuit vertically distributed, and cooperate with the round edge of the rotor to make the air gap approach a sinusoidal distribution. The magnetic flux sorting groove is also helpful for motor noise reduction.

[0020] In order to further better realize the present invention, the following setting structure is particularly adopted: the magnetic flux sorting groove is located outside the magnetic steel groove.

[0021] The present invention also provides an electrical appliance, which adopts the above-mentioned motor based on the round edge design of the rotor.

[0022] When the above-mentioned configuration structure is adopted, the motor used in the electrical appliance has lower noise, lower motor iron loss and higher motor efficiency.

[0023] The present invention has the following advantages and beneficial effects:

[0024] (1) In the present invention, the motor is different from the prior art in that the non-uniform air gap is obtained. This scheme is based on the rotor round edge design. By analyzing the stator and rotor air gaps, a motor based on the rotor round edge design is obtained. In order to make the magnetic field distribution in the air gap as close to a sine wave as possible, the rotor round edge is designed based on the minimum air gap Δδ, the magnetic steel length L, and the stator tooth round edge as the design basis to obtain a non-uniform air gap. Taking the second scattered point as the reference, the first scattered point of the air gap Δδ1, the third scattered point of the air gap Δδ1, the fourth scattered point of Δδ2, and the fifth scattered point of the air gap Δδ3 are obtained by moving ΔL horizontally left and right along the tangential direction passing through it, so that the rotor round edge passes through these scattered points, which can effectively reduce the back electromotive force harmonics, reduce the motor iron loss, and improve the motor efficiency.

[0025] (2) In the present invention, the motor used in the electrical appliance has low noise, low iron loss and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a structural schematic diagram of the rotor assembly and the stator assembly in the motor;

[0028] Figure 2 yes Figure 1 Partial schematic diagram of the middle A section;

[0029] Figure 3 It is a schematic diagram of the positional relationship and related dimensions of each scattered point;

[0030] Figure 4 is a schematic diagram of the first circle edge;

[0031] Figure 5 is a schematic diagram of the second circle edge;

[0032] Figure 6 is a schematic diagram of the third circle edge and the fourth circle edge;

[0033] Figure 7 The back electromotive force waveform of the motor at 3600rpm is obtained by simulation;

[0034] Figure 8 It is a histogram obtained by Fourier transforming the simulation data;

[0035] The markings in the figure are:

[0036] 1-rotor round edge; 2-stator tooth round edge; 3-magnetic flux sorting slot; 4-magnetic steel slot; 5-magnetic steel;

[0037] 10-first scatter point; 11-second scatter point; 12-third scatter point; 13-fourth scatter point; 14-fifth scatter point; 15-sixth scatter point;

[0038] 101 - first circular edge; 102 - second circular edge; 103 - third circular edge; 104 - fourth circular edge. DETAILED DESCRIPTION

[0039] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0040] Embodiment 1:

[0041] A motor based on the rounded edge design of the rotor can effectively reduce the back EMF harmonics, reduce the motor iron loss, and improve the motor efficiency. Figure 1-Figure 8 As shown, it is particularly configured as follows:

[0042] The motor comprises a rotor assembly and a stator assembly. The rotor core of the rotor assembly has six magnetic steel slots 4, which are spaced apart along the circumferential direction of the rotor core, and each magnetic steel slot 4 is equipped with a corresponding magnetic steel 5, wherein the length of the magnetic steel 5 is recorded as L.

[0043] The stator assembly comprises stator teeth which are arranged at intervals in the circumferential direction, and the inner edges of the stator teeth form stator tooth circular edges 2 .

[0044] In this embodiment, for the convenience of description, the motor is placed horizontally, and the uppermost magnet 5 of the rotor assembly is arranged horizontally, with the upper part of the magnet 5 facing the stator teeth. The following description takes the uppermost magnet 5 as an example.

[0045] The outer circle of the rotor assembly includes multiple sections of rotor circular edges 1 connected in sequence. Taking the rotor circular edge 1 corresponding to the top magnetic steel 5 as an example, the rotor circular edge 1 includes a first scattered point 10, a second scattered point 11, a third scattered point 12, a fourth scattered point 13 and a fifth scattered point 14 arranged in sequence along the circumferential direction of the outer circle of the rotor assembly, and the second scattered point 11 is located on the bisector of the magnetic steel slot 4 passing through the center of the rotor assembly.

[0046] In order to make the magnetic field distribution in the air gap as close to a sine wave as possible, it is necessary to use the second scattered point 11 as a reference, and distribute the remaining scattered points on both sides thereof, and the second scattered point 11 is positioned at the minimum air gap. Specifically, from the second scattered point 11 along the tangent direction (lateral direction) of the rotor circular edge 1, the lateral spacings of the first scattered point 10, the second scattered point 11, the third scattered point 12, the fourth scattered point 13 and the fifth scattered point 14 are all equal, the first scattered point 10 is located on the left side of the second scattered point 11, and the remaining scattered points are located on the right side of the second scattered point 11. The lateral spacing between adjacent scattered points is recorded as ΔL. Taking the stator tooth circular edge 2 of the stator tooth portion as a reference, at the first scattered point 10 At the third scattered point 12, an air gap Δδ1 is formed between the rotor circular edge 1 and the stator tooth circular edge 2, at the second scattered point 11, a minimum air gap Δδ is formed between the rotor circular edge 1 and the stator tooth circular edge 2, at the fourth scattered point 13, an air gap Δδ2 is formed between the rotor circular edge 1 and the stator tooth circular edge 2, at the fifth scattered point 14, an air gap Δδ3 is formed between the rotor circular edge 1 and the stator tooth circular edge 2, Δδ is the minimum air gap; wherein, Δδ1=Δδ / cosθ, Δδ2=Δδ / cos(θ+Δθ), Δδ3=Δδ / (θ+2Δθ), θ and Δθ are angles for making the air gap magnetic field tend to a sinusoidal setting.

[0047] The rotor circular edge 1 includes a first circular edge 101, a second circular edge 102 and a third circular edge 103. The first circular edge 101, the second circular edge 102 and the third circular edge 103 are connected in sequence, and all the rotor circular edges 1 are connected end to end through the circular edges to form a complete outer circle. The first scattered point 10, the second scattered point 11 and the third scattered point 12 are on the first circular edge 101, and the first scattered point 10 and the third scattered point 12 are the endpoints of the first circular edge 101; the third scattered point 12, the fourth scattered point 13 and the fifth scattered point 14 are on the second circular edge 102, and the third scattered point 12 and the fifth scattered point 14 are the endpoints of the second circular edge 102; the third circular edge is an arc segment passing through the fifth scattered point 14, with the center of the rotor assembly as the center of the circle and the distance from the fifth scattered point 14 to the center of the rotor assembly as the radius, and the fifth scattered point 14 is the endpoint of the third circular edge 103. A segmented round edge design is adopted to obtain an uneven air gap, so as to improve the air gap magnetic field distribution (close to sinusoidal), reduce the back EMF distortion rate, reduce the motor noise, reduce the motor iron loss, and thus improve the motor efficiency.

[0048] Among them, the air gap relationship satisfies: Δδ<Δδ1<Δδ2<Δδ3; ΔL should be less than or equal to 1 / 6L. When ΔL=1 / 6L, in order to obtain a better air gap magnetic field distribution effect, θ and Δθ satisfy: 0.7<θ / Δθ<1.5. Further, θ and Δθ satisfy: 13°<θ<17°, 14°<Δθ<16°, in order to obtain a better air gap magnetic field distribution effect.

[0049] The above scheme is different from the existing technology in obtaining uneven air gaps. This scheme is based on the rotor round edge design. Through the analysis of the stator and rotor air gaps, a motor based on the rotor round edge design is obtained. The idealized sinusoidal air gap magnetic density air gap design satisfies: Δδ(x) = δ / cos(π*x / l) in the longitudinal direction, where l is the pole length, but it is difficult to achieve according to such a design, so it is simplified to divide the air gap in the longitudinal direction into three sections in the direction of the horizontal length in the middle of the pole, and the air gaps are Δδ1, Δδ2, and Δδ3 respectively. In order to make the magnetic field distribution in the air gap as close to the sine wave as possible, the rotor round edge 1 is designed based on the minimum air gap Δδ, the magnetic steel length L, and the stator tooth round edge 2 as the design basis. The uneven air gap is obtained by the above formula, so that the air gap magnetic field distribution tends to be sinusoidal. Taking the second scattered point 11 as a reference, a first scattered point 10 of the air gap Δδ1, a third scattered point 12 of the air gap Δδ1, a fourth scattered point 13 of Δδ2 and a fifth scattered point 14 of the air gap Δδ3 are obtained by moving the tangential direction thereof horizontally by ΔL, so that the circular edge of the rotor passes through these scattered points, which can effectively reduce the back electromotive force harmonics, reduce the iron loss of the motor and improve the efficiency of the motor.

[0050] Adjacent rotor circular edges 1 can be connected through the outer circle of the straight line segment or through the circular edge. This embodiment is described by taking the circular edge as the connection node as an example, and the rotor circular edge 1 also includes a fourth circular edge 104, the head end point of the fourth circular edge 104 is the fifth scattered point 14, and the end end point of the fourth circular edge 104 is co-point with the first scattered point 10 of the head end of another segment of the rotor circular edge 1 connected. As a preferred embodiment of the fourth circular edge 104, the outer circle of the rotor assembly includes a sixth scattered point 15, at which an air gap Δδ2 is formed between the rotor circular edge 1 and the stator tooth circular edge 2, and the sixth scattered point 15 is located on the fourth circular edge 104. The rotor assembly adopts a segmented circular edge design, and obtains an uneven air gap with the stator tooth portion, which improves the air gap magnetic field distribution (close to sine), reduces the back electromotive force distortion rate, reduces motor noise, reduces motor iron loss, and thus improves motor efficiency.

[0051] As a preferred solution of the rotor core, the rotor core of the rotor assembly is provided with a magnetic flux sorting groove 3, which is located outside the magnetic steel groove 4. After the magnetic flux sorting groove is provided in the rotor, the magnetic flux sorting groove can standardize the air gap magnetic circuit, reduce the harmonic content of the motor, and make the air gap magnetic circuit run in the vertical direction to achieve vertical distribution. With the above-mentioned rounded edge of the rotor, the magnetic field distribution in the air gap is closer to the sinusoidal distribution. In addition, the magnetic flux sorting groove is also helpful for motor noise reduction.

[0052] A simulation model was built based on the rounded edge design of the rotor, and the back EMF of the motor at a speed of 3600 rpm was obtained by simulation. Figure 7 The back EMF voltage amplitude at each frequency is obtained by Fourier transform, as shown in Table 1. A bar graph is generated based on Table 1. Figure 8As shown, due to the low content of even harmonics, they can be ignored in Fourier analysis, and the odd harmonics are mainly calculated. The calculated harmonic distortion rate with back-EMF is only 2.6%.

[0053] Table 1: The amplitude of the back EMF voltage at each frequency obtained by Fourier transform of the back EMF

[0054] harmonic 1 3 5 7 9 11 13 Amplitude 265.0895 0.19331 0.26207 1.13779 0.20629 1.37736 3.87114

[0055] Embodiment 2:

[0056] This embodiment provides an electrical appliance based on the embodiment 1, and particularly adopts the following configuration structure:

[0057] This embodiment provides an electrical appliance, the motor used in the electrical appliance is the motor based on the rounded edge design of the rotor in Embodiment 1, and can be an air conditioner using the motor based on the rounded edge design of the rotor in Embodiment 1, or a refrigerator, or a fan, etc. Because the motor used in the electrical appliance has low noise, low iron loss, and high efficiency, it has better use effect.

[0058] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A motor based on a rotor round edge design, characterized in that: The invention comprises a rotor assembly and a stator assembly, wherein the rotor assembly comprises magnetic steel slots (4) distributed at intervals in the circumferential direction and magnetic steels (5) installed in the magnetic steel slots (4), and the length of the magnetic steels (5) is L; and the stator assembly comprises stator teeth arranged at intervals in the circumferential direction; The outer circle of the rotor assembly comprises a plurality of rotor circular edges (1), the rotor circular edge (1) comprising a first scattered point (10), a second scattered point (11), a third scattered point (12), a fourth scattered point (13) and a fifth scattered point (14) arranged in sequence along the circumferential direction, the second scattered point (11) being located on a bisector of the magnetic steel slot (4) passing through the center of the rotor assembly; From the second scattered point (11) along the tangent direction of the rotor circular edge (1), the lateral spacings of the first scattered point (10), the second scattered point (11), the third scattered point (12), the fourth scattered point (13) and the fifth scattered point (14) are all equal, and the lateral spacing between adjacent scattered points is recorded as ΔL; Taking the stator tooth circular edge (2) of the stator tooth portion as a reference, at the first scattered point (10), the second scattered point (11), the third scattered point (12), the fourth scattered point (13) and the fifth scattered point (14), air gaps Δδ1, Δδ, Δδ1, Δδ2 and Δδ3 are respectively formed between the rotor circular edge (1) and the stator tooth circular edge (2), Δδ being the minimum air gap; Among them, Δδ1=Δδ / cosθ, Δδ2=Δδ / cos(θ+Δθ), Δδ3=Δδ / (θ+2Δθ), θ and Δθ are the angles set to make the air gap magnetic field tend to be sinusoidal.

2. The motor based on the rotor round edge design according to claim 1, characterized in that: The air gap relationship satisfies: Δδ<Δδ1<Δδ2<Δδ3.

3. The motor based on the rotor round edge design according to claim 1, characterized in that: ΔL≤1 / 6L.

4. The motor based on the rotor round edge design according to claim 3 is characterized in that: When ΔL=1 / 6L, 0.7<θ / Δθ<1.

5.

5. The motor based on the rotor round edge design according to claim 4, characterized in that: When ΔL=1 / 6L, θ and Δθ satisfy: 13°<θ<17°, 14°<Δθ<16°.

6. A motor based on a rotor round edge design according to any one of claims 1 to 5, characterized in that: The rotor circular edge (1) comprises a first circular edge (101), a second circular edge (102) and a third circular edge (103) which are connected in sequence; The first scattered point (10), the second scattered point (11) and the third scattered point (12) are on the first circular edge (101), and the first scattered point (10) and the third scattered point (12) are endpoints of the first circular edge (101); The third scattered point (12), the fourth scattered point (13) and the fifth scattered point (14) are on the second circular edge (102), and the third scattered point (12) and the fifth scattered point (14) are endpoints of the second circular edge (102); The third circular edge is an arc segment passing through the fifth scattered point (14), with the center of the rotor assembly as the center of the circle and the distance between the fifth scattered point (14) and the center of the rotor assembly as the radius, and the fifth scattered point (14) is the endpoint of the third circular edge (103).

7. The motor based on the rotor round edge design according to claim 6, characterized in that: The rotor circular edge (1) further comprises a fourth circular edge (104), the first end point of the fourth circular edge (104) being the fifth scattered point (14), and the last end point of the fourth circular edge (104) being co-pointed with the first scattered point (10) at the first end of another connected section of the rotor circular edge (1).

8. The motor based on the rotor round edge design according to claim 7, characterized in that: The outer circle of the rotor assembly includes a sixth scattered point (15), at which an air gap Δδ2 is formed between the rotor circular edge (1) and the stator tooth circular edge (2), and the sixth scattered point (15) is located on the fourth circular edge (104).

9. The motor based on the rotor round edge design according to claim 1, characterized in that: The rotor core of the rotor assembly is provided with a magnetic flux sorting groove (3).

10. The motor based on the rotor round edge design according to claim 9, characterized in that: The magnetic flux sorting groove (3) is located outside the magnetic steel groove (4).

11. An electrical appliance, characterized in that: A motor based on a rotor round edge design as described in any one of claims 1 to 10.

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