Rotor structure of a compressor motor and compressor

Abstract

The utility model provides a kind of rotor structure and compressor of compressor motor, wherein rotor structure includes rotor core, the circumferential of the rotor core is provided with multiple magnetic steel slots same as each other and multiple flow holes same as each other, at least two groups of magnetic separation hole with the D axis symmetry of rotor core are provided between the magnetic steel slot and the rotor core outer wall, respectively first magnetic separation hole and second magnetic separation hole, the D axis coincides or parallel with rotor magnetic pole axis, first magnetic separation hole is relatively close to D axis relative to second magnetic separation hole, the area of first magnetic separation hole on axial section is S1, the area of second magnetic separation hole on axial section is S2, S1 and S2 satisfy the following relation formula: Wherein, S T It is single flow hole area, S C It is single magnetic steel slot area.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, specifically to a rotor structure for permanent magnet synchronous motors, particularly for air conditioner compressor motors. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in variable frequency compressors due to their high power density and efficiency. However, during operation, the magnetic permeability of the air gap between the stator and rotor fluctuates circumferentially due to the opening of the stator slots. Simultaneously, they are affected by harmonics from the three-phase AC current in the stator, resulting in magnetic field harmonics within the air gap. These harmonics generate back EMF harmonics and cogging torque, leading to increased torque fluctuations and noise during load operation, thus affecting motor performance and user experience.

[0003] To reduce torque ripple and noise, existing technologies typically optimize the magnetic circuit by incorporating magnetic isolation holes near the rotor magnet slots. For example, patent document CN109962545B discloses a method that eliminates harmonics and reduces noise in the stator-rotor air gap by segmenting the magnetic pole arcs on the rotor's outer periphery and setting a specific ratio between the radius and the central angle, thereby improving the sinusoidal nature of the back EMF waveform and reducing torque ripple under motor load. Patent document CN217956805U discloses a rotor lamination structure with a special V-shaped magnet slot group and magnetically guided protrusions, designed to improve the saliency ratio and torque density of the rotor.

[0004] However, in existing technologies, when setting magnetic isolation holes within the limited space between the rotor magnet slots and the rotor outer wall, setting too many or poorly shaped magnetic isolation holes may increase manufacturing complexity and cost, and may lead to magnetic circuit saturation or a reduction in the effective magnetic conduction area, resulting in a loss of motor output torque and a decrease in efficiency. Therefore, how to effectively suppress harmonics and reduce torque ripple within the limited rotor space by optimizing the design of magnetic isolation holes, while avoiding negative impacts on motor efficiency and output torque, has become a technical problem that needs to be solved in this field. Utility Model Content

[0005] In view of the above-mentioned problems in the prior art, the purpose of this utility model is to provide a rotor structure for a compressor motor. By optimizing the shape, size and position of the magnetic isolation hole, the magnetic flux density distribution in the air gap is effectively improved, the back EMF harmonic content and torque pulsation are reduced, thereby improving motor efficiency and reducing operating noise.

[0006] Specifically, this utility model provides a rotor structure for a compressor motor, including a rotor core. The rotor core has multiple magnetic slots of equal area and multiple flow holes of equal area arranged circumferentially. At least two sets of magnetic isolation holes symmetrical about the D-axis of the rotor core are provided between the magnetic slots and the outer wall of the rotor core, namely a first magnetic isolation hole and a second magnetic isolation hole. The D-axis coincides with or is parallel to the rotor magnetic pole axis. The first magnetic isolation hole is closer to the D-axis than the second magnetic isolation hole. The characteristic feature is that:

[0007] The area of ​​the first magnetic isolation hole in the axial section is S1, and the area of ​​the second magnetic isolation hole in the axial section is S2. S1 and S2 satisfy the following relationship:

[0008]

[0009] Among them, S T S represents the area of ​​a single flow hole. C The area of ​​a single magnet slot.

[0010] Furthermore, the second magnetic isolation hole includes two arcs R concentric with the arc R3 at the tail end of the magnet groove. 21 and R 22 It satisfies the following relationship:

[0011] R3<|R 21 -R 22 |<(Rr) / P

[0012] Where R is the outer radius of the rotor core, r is the inner radius of the rotor hole, and P is the number of rotor pole pairs.

[0013] Furthermore, the angle between the straight line from the rotor center to the farthest end of the first magnetic isolation hole and the D-axis is θ1, and the angle between the straight line from the rotor center to the farthest end of the second magnetic isolation hole and the D-axis is θ2, where 0 < θ1 < θ2 < 20°.

[0014] Furthermore, the shortest distance between the first magnetic isolation hole and the outer wall of the rotor core is L. 11 Satisfying L 11 ≤R / Q, where Q is the number of stator teeth of the stator that mates with the rotor.

[0015] Furthermore, the first magnetic isolation hole and / or the second magnetic isolation hole are composed of a straight line segment, a circular arc, or a combination of a straight line segment and a circular arc.

[0016] Furthermore, the first magnetic isolation hole comprises at least two straight line segments, and the included angle between the two straight line segments is θ. 11 , satisfying 0≤θ 11 ≤10°.

[0017] Furthermore, the maximum width of the first magnetic isolation hole along the extension direction of the magnetic groove is L. 12 Satisfying L 11 / 2≤L 12 ≤L C L C The width of the magnetic groove.

[0018] Furthermore, the outer wall of the rotor core is composed of a first outer wall and a second outer wall arranged alternately in the circumferential direction of the rotor. The first outer wall is an arc segment and symmetrical about the D-axis, and the second outer wall is a straight segment and symmetrical about the Q-axis, wherein the electrical angle difference between the Q-axis and the D-axis is 90°. Alternatively, the second outer wall is a curved segment that is concave inward of the rotor and symmetrical about the Q-axis, with the center of the second outer wall located outside the rotor.

[0019] According to another aspect of this utility model, a compressor is provided, including the rotor structure described above.

[0020] In summary, the beneficial effects brought about by the design of this utility model are: by setting and adjusting the size of the magnetic isolation hole in the rotor core, the air gap magnetic flux density is made closer to a sinusoidal distribution, thereby reducing torque pulsation and improving efficiency. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the rotor structure of Embodiment 1 of this utility model.

[0023] Figure 2 This is a partially enlarged schematic diagram of the first and second magnetic isolation holes.

[0024] Figure 3 This is a schematic diagram of the rotor structure using a conventional magnetic isolation hole scheme in existing technology.

[0025] Figure 4 This is a schematic diagram of the rotor structure of Embodiment 2 of this utility model.

[0026] Figure 5 This is a partially enlarged schematic diagram of the first magnetic isolation hole and the magnetic steel groove.

[0027] Figure 6 This is a comparison of the embodiments of this utility model with conventional solutions in terms of back EMF harmonics.

[0028] Figure 7 This is a comparison of the embodiment of this utility model with conventional solutions in terms of torque fluctuation.

[0029] Explanation of reference numerals in the attached figures:

[0030] 10. Rotor core; 11. Magnet slot; 12. First magnetic isolation hole; 13. Second magnetic isolation hole; 14. Outer wall of rotor core; 141. First outer wall; 142. Second outer wall; 15. Flow hole; R, radius of rotor outer wall; r, radius of rotor inner hole; R3, radius of arc at the tail end of magnet slot; R 21 ,R 22 θ1, the radius of the second magnetic isolation hole's arc; θ2, the angle between the far end of the first magnetic isolation hole and the D-axis; θ3, the angle between the far end of the second magnetic isolation hole and the D-axis; θ4, θ5, θ6, θ7, θ8, θ9, θ1, θ1, θ2, θ1, θ2, θ3, θ4, θ5, θ6, θ7, θ8 11 The angle between the two straight segments of the first magnetic isolation hole; L 11 The shortest distance between the first magnetic isolation hole and the outer wall of the rotor core; L C Width of the magnet slot. Detailed Implementation

[0031] The following description, in conjunction with the accompanying drawings, further illustrates the specific embodiments of the present invention, providing a clearer understanding of its details. However, the specific embodiments described herein are for illustrative purposes only and should not be construed as limiting the scope of the invention in any way. Under the guidance of this invention, those skilled in the art can conceive of any possible modifications based on it, and these should all be considered within the scope of the invention.

[0032] In the prior art, the rotor structure of the conventional magnetic isolation hole scheme is referenced Figure 3 As shown, in the conventional scheme, the magnetic isolation holes are arranged in two sets of magnetic isolation holes with different areas, one large and one small, and the magnetic isolation holes are elongated.

[0033] In this invention, the size of the magnetic isolation hole is set and adjusted to make the air gap magnetic flux density closer to a sinusoidal distribution, thereby reducing torque pulsation and improving efficiency.

[0034] Example 1:

[0035] This embodiment provides a rotor structure for a compressor motor, such as... Figure 1As shown, the rotor core 10 includes a plurality of magnetic slots 11 of equal area and a plurality of flow holes 15 of equal area arranged circumferentially thereon. At least two sets of magnetic isolation holes symmetrical about the D-axis of the rotor core 10 are provided between the magnetic slots 11 and the outer wall 14 of the rotor core, namely a first magnetic isolation hole 12 and a second magnetic isolation hole 13. The D-axis coincides with or is parallel to the rotor magnetic pole axis. The first magnetic isolation hole 12 is closer to the D-axis than the second magnetic isolation hole 13. The area of ​​the first magnetic isolation hole 12 in the axial section is S1, and the area of ​​the second magnetic isolation hole 13 in the axial section is S2. S1 and S2 satisfy the following relationship:

[0036]

[0037] Among them, S T S represents the area of ​​a single flow hole. C The area of ​​a single magnet slot.

[0038] By employing the above formula, this embodiment constrains the area difference between the first and second magnetic isolation holes, thus avoiding insufficient harmonic suppression due to excessively small area differences, while also preventing the risk of magnetic circuit breakage caused by excessively large area differences. Furthermore, the area parameter S of the flow hole and the magnet groove... T and S C These are inherent design parameters of the rotor structure. The square root of their difference is used as the upper limit of the difference in the area of ​​the magnetic isolation hole. This eliminates the need to introduce new design variables, reduces design complexity, and ensures that the size of the magnetic isolation hole is compatible with the overall rotor structure.

[0039] Furthermore, in this embodiment, the shape of the second magnetic isolation hole 13 has been optimized, such as... Figure 2 As shown, the second magnetic isolation hole 13 includes two arcs R concentric with the arc R3 at the tail end of the magnet groove. 21 and R 22 It satisfies the following relationship:

[0040] R3<|R 21 -R 22 |<(Rr) / P

[0041] Where R is the outer radius of the rotor core, r is the inner radius of the rotor hole, and P is the number of rotor pole pairs.

[0042] In this embodiment, the second magnetic isolation hole 13 adopts a double arc R concentric with the arc R3 at the tail end of the magnetic steel groove. 21 R 22 This design allows the magnetic flux to flow smoothly into the air gap along the tangent of the concentric arc after it flows out of the magnetic steel groove, avoiding magnetic flux loss caused by abrupt changes in the shape of the magnetic isolation hole and reducing local magnetic concentration.

[0043] Furthermore, such as Figure 1 As shown, if the angle between the straight line from the rotor center to the farthest point of the first magnetic isolation hole 12 and the D-axis is set as θ1, and the angle between the straight line from the rotor center to the farthest point of the second magnetic isolation hole 13 and the D-axis is set as θ2, then in this embodiment, 0 < θ1 < θ2 < 20° must be satisfied. Through this design, the radial position of the magnetic isolation hole can be precisely controlled, and the air gap magnetic flux density distribution can be optimized.

[0044] Furthermore, in this embodiment, the shortest distance between the first magnetic isolation hole 12 and the outer wall 14 of the rotor core is defined as L. 11 ,like Figure 2 As shown, L 11 L needs to be satisfied 11 ≤R / Q, where Q is the number of stator teeth that mate with the rotor. In this embodiment, the number of stator teeth is 9 or 12.

[0045] By establishing a correspondence between the magnetic isolation holes and the stator teeth, it is ensured that the magnetic isolation holes can accurately block the harmonic magnetic flux generated by the stator tooth slots; simultaneously, L 11 The upper limit is set to prevent the magnetic isolation holes from getting too close to the outer wall of the rotor, ensuring that the thickness of the outer wall of the rotor is sufficient to withstand the centrifugal force during high-speed operation.

[0046] Furthermore, the first magnetic isolation hole 12 and / or the second magnetic isolation hole 13 are composed of straight line segments, circular arcs, or a combination of straight line segments and circular arcs. This variety of structural forms allows the magnetic isolation holes to adapt to magnetic grooves of different shapes. In addition, the first magnetic isolation hole 12 includes at least two straight line segments, and the included angle between the two straight line segments is θ. 11 , satisfying 0≤θ 11 ≤10°, such as Figure 2 As shown. When θ 11 When θ = 0°, the two straight line segments are parallel, and the first magnetic isolation hole 12 is rectangular, which is suitable for regions with a relatively uniform magnetic flux direction; when θ 11 When the angle is 10°, the two straight segments of the first magnetic isolation hole 12 open slightly outward, which can expand the magnetic isolation range and is suitable for areas where magnetic flux diverges.

[0047] Furthermore, such as Figure 5 As shown, the maximum width of the first magnetic isolation hole 12 along the extension direction of the magnetic groove is L. 12 This embodiment needs to satisfy L. 11 / 2≤L 12 ≤L C L C L is the width of the magnet slot. The width of the magnetic isolation hole is adapted to match the magnetic flux output width of the magnet slot: 12 ≥L 11 / 2 ensures that the magnetic isolation hole has sufficient lateral magnetic isolation range, preventing magnetic flux from bypassing the sides of the magnetic isolation hole; L 12 ≤LC This prevents the width of the magnetic shielding hole from exceeding the magnetic steel groove, thus avoiding obstruction of the magnetic flux output path of the magnetic steel.

[0048] In this embodiment, the structure of the rotor outer wall is further optimized, referring to... Figure 3 Specifically, the outer wall 14 of the rotor core is composed of a first outer wall 141 and a second outer wall 142 arranged alternately in the circumferential direction of the rotor. The first outer wall 141 is an arc segment and symmetrical about the D-axis, while the second outer wall 142 is a straight segment and symmetrical about the Q-axis, where the Q-axis is the quadrature axis and its electrical angle difference from the D-axis is 90°. Through the design of the first outer wall 141 and the second outer wall 142 in this embodiment, the uniformity of the air gap magnetic flux density and heat dissipation performance can be improved.

[0049] Example 2:

[0050] Reference Figure 4 The second outer wall 142 of the outer wall 14 of the rotor core is a curved segment that is concave into the rotor and symmetrical about the Q axis. In this example, the center of the second outer wall 142 is outside the rotor.

[0051] Other implementation methods in this embodiment are the same as in Embodiment 1.

[0052] Example 3:

[0053] This embodiment provides a compressor that includes the rotor structure described in the above-described embodiment.

[0054] Other implementation methods in this embodiment are the same as in Embodiment 1 or 2.

[0055] Testing of technical effectiveness:

[0056] By setting and adjusting the size of the magnetic isolation holes in the rotor core, the air gap magnetic flux density is made closer to a sinusoidal distribution, thereby reducing torque pulsation and improving efficiency. The back EMF harmonic content and torque fluctuation are tested using industry-standard calculation methods: the back EMF signal is sampled within one cycle and then subjected to a Fourier transform to obtain the back harmonic content; torque fluctuation is tested according to the national standard GB / T30549-2014.

[0057] like Figure 6 and Figure 7 As shown, compared with conventional solutions, the back EMF harmonic content and torque fluctuation value are significantly reduced by the solution of this utility model.

[0058] The above are merely specific embodiments of the utility model, but the scope of protection of the utility model is not limited thereto. Any changes or substitutions conceived without creative effort should be included within the scope of protection of the utility model. Therefore, the scope of protection of the utility model should be determined by the scope of protection defined in the claims.

[0059] The invention shown and described herein can be implemented in the absence of any elements or limitations specifically disclosed herein. The terminology and expressions used are intended to be descriptive and not limiting, and it is not intended that any equivalents of the features shown and described herein or any parts thereof be excluded in the use of such terminology and expressions. It should be recognized that various modifications are possible within the scope of this invention. Therefore, it should be understood that although the invention has been specifically disclosed by way of various embodiments and optional features, modifications and variations of the concepts herein can be adopted by those skilled in the art, and such modifications and variations are considered to fall within the scope of the invention as defined in the appended claims.

[0060] The contents of any articles, patents, patent applications, and all other documents and information available electronically herein are incorporated herein by reference in their entirety, as if each individual publication were specifically and individually cited for reference. The applicant reserves the right to incorporate any and all material and information from any such articles, patents, patent applications, or other documents into this application.

Claims

1. A rotor structure for a compressor motor, comprising a rotor core, wherein the rotor core is provided with a plurality of magnetic slots of equal area and a plurality of flow holes of equal area in its circumferential direction, and at least two sets of magnetic isolation holes symmetrical about the D-axis of the rotor core are provided between the magnetic slots and the outer wall of the rotor core, namely a first magnetic isolation hole and a second magnetic isolation hole, wherein the D-axis coincides with or is parallel to the rotor magnetic pole axis, and the first magnetic isolation hole is closer to the D-axis than the second magnetic isolation hole, characterized in that: The area of ​​the first magnetic isolation hole in the axial section is S1, and the area of ​​the second magnetic isolation hole in the axial section is S2. S1 and S2 satisfy the following relationship: 0≤|S_1-S_2 |≤√(|S_T-S_C |) Where ST is the area of ​​a single flow hole and SC is the area of ​​a single magnet slot.

2. The rotor structure of the compressor motor according to claim 1, characterized in that: The second magnetic isolation hole includes two arcs R concentric with the arc R3 at the tail end of the magnet groove. 21 and R 22 It satisfies the following relationship: R_3<|R_21-R_22 |<(Rr) / P Where R is the outer radius of the rotor core, r is the inner radius of the rotor hole, and P is the number of rotor pole pairs.

3. The rotor structure of the compressor motor according to claim 1, characterized in that: The angle between the straight line from the rotor center to the farthest end of the first magnetic isolation hole and the D-axis is θ1, and the angle between the straight line from the rotor center to the farthest end of the second magnetic isolation hole and the D-axis is θ2, where 0 < θ_1 < θ_2 < 20°.

4. The rotor structure of the compressor motor according to claim 1 or 2, characterized in that: The shortest distance between the first magnetic isolation hole and the outer wall of the rotor core is L11, which satisfies L_11≤R / Q, where Q is the number of stator teeth of the stator that cooperate with the rotor.

5. The rotor structure of the compressor motor according to claim 1, characterized in that: The first magnetic isolation hole and / or the second magnetic isolation hole are composed of a straight line segment, a circular arc, or a combination of a straight line segment and a circular arc.

6. The rotor structure of the compressor motor according to claim 1, characterized in that, The first magnetic isolation hole includes at least two straight line segments, and the included angle between the two straight line segments is θ11, which satisfies 0≤θ_11≤10°.

7. The rotor structure of the compressor motor according to claim 1, characterized in that: The maximum width of the first magnetic isolation hole along the extension direction of the magnetic steel groove is L12, which satisfies L11 / 2≤L12≤LC, where LC is the width of the magnetic steel groove.

8. The rotor structure of the compressor motor according to claim 1, characterized in that: The outer wall of the rotor core is composed of a first outer wall and a second outer wall arranged alternately in the circumferential direction of the rotor. The first outer wall is an arc segment and is symmetrical about the D axis, and the second outer wall is a straight segment and is symmetrical about the Q axis. The electrical angle difference between the Q axis and the D axis is 90°.

9. The rotor structure of the compressor motor according to claim 8, characterized in that: The outer wall of the rotor core is composed of a first outer wall and a second outer wall arranged alternately in the circumferential direction of the rotor. The first outer wall is an arc segment and is symmetrical about the D axis. The second outer wall is a curved segment that is concave into the rotor and is symmetrical about the Q axis. The center of the second outer wall is outside the rotor.

10. A compressor, characterized in that: The rotor structure of the compressor motor is included as described in any one of claims 1 to 9.

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