Motor rotor and self-starting synchronous reluctance motor

Abstract

This application provides a motor rotor and a self-starting synchronous reluctance motor. The motor rotor includes a rotor core (1) and end rings (7) disposed at both ends of the rotor core (1). Magnetic barrier slots are provided on the rotor core (1), including cast aluminum slots (5). Guide bars (9) are disposed in the cast aluminum slots (5). The end rings (7) are connected to at least a portion of the guide bars (9) to form a loop. On the longitudinal section passing through the central axis of the rotor core (1), the longitudinal cross-sectional area of ​​one side of the end ring (7) is Se, and the cross-sectional area of ​​the guide bars (9) perpendicular to the central axis of the rotor core (1) is Sr. The longitudinal cross-sectional area Se of the end ring (7) at any position is proportional to the cross-sectional area Sr of the guide bars (9) forming the loop with the end ring. According to the motor rotor of this application, at any time, the cross-sectional area of ​​the end ring is equivalent to the cross-sectional area of ​​the guide bars forming the loop, which can effectively improve the torque pulsation caused by the sudden change in resistance and ensure the starting capability of the motor.

Description

Technical Field

[0001] This application relates to the field of motor technology, specifically to a motor rotor and a self-starting synchronous reluctance motor. Background Technology

[0002] Self-starting synchronous reluctance motors combine the characteristics of both asynchronous motors and synchronous reluctance motors, and have the following basic features:

[0003] 1. Air slots are opened along the axial direction inside the rotor. These air slots are called magnetic barrier slots. The iron core part formed between every two layers of magnetic barrier slots is called the magnetic channel.

[0004] 2. The magnetic barrier groove is filled entirely or partially with conductive but non-magnetic material (such as aluminum), which is called a conductor bar;

[0005] 3. The rotor has end rings at both ends of the axial direction. The end rings are made of the same material as the guide bars. The end rings at both ends of the rotor are connected to all or part of the guide bars in the rotor slots to form a short circuit loop.

[0006] 4. Each pole of the rotor forms two symmetrical axes, the D-axis and the Q-axis. The axis that is approximately parallel to the magnetic channel is called the D-axis, and the axis that is approximately perpendicular to the magnetic channel is called the Q-axis.

[0007] The self-starting synchronous reluctance motor combines the advantages of asynchronous motors (no frequency converter required for direct starting, no magnets on the rotor, and high reliability) with the advantages of synchronous reluctance motors (stable operation in sync, high efficiency, and high power density). In the industrial field, the IE4 fixed-frequency motor achieves breakthroughs in energy efficiency while also being more cost-effective.

[0008] The starting process of a self-starting synchronous reluctance motor is divided into a starting stage and a pull-in stage. The pull-in stage requires the speed to reach the synchronous speed completely, which is quite difficult. To enhance the starting capability, it is necessary to reduce the rotor resistance, that is, the resistance of the short-circuit ring formed by the rotor's internal guide bars and end rings.

[0009] During motor startup, the rotor moves relative to the stator magnetic field and there is a speed difference. At different times, the rotor circuit is composed of different slot bars and end rings. If the resistance is different at different times, it will cause torque pulsation, which weakens the starting capability. Summary of the Invention

[0010] Therefore, the technical problem to be solved by this application is to provide a motor rotor and a self-starting synchronous reluctance motor, wherein the cross-sectional area of ​​the lower end ring is equivalent to the cross-sectional area of ​​the conductor bar constituting the circuit at any time, which can effectively improve the torque pulsation caused by the sudden change in resistance and ensure the starting capability of the motor.

[0011] To address the aforementioned problems, this application provides a motor rotor, comprising a rotor core and end rings disposed at both ends of the rotor core. The rotor core has magnetic barrier slots, each including a cast aluminum slot. A guide bar is disposed within the cast aluminum slot. The end rings are connected to at least a portion of the guide bar to form a loop. On a longitudinal section passing through the central axis of the rotor core, the single-sided longitudinal cross-sectional area of ​​the end ring is Se, and the cross-sectional area of ​​the guide bar perpendicular to the central axis of the rotor core is Sr. The longitudinal cross-sectional area Se of the end ring at any position is proportional to the cross-sectional area Sr of the guide bar at the point where the loop is formed with the end ring.

[0012] Preferably, the end ring is circular, the axial height of the end ring is He, the cross-sectional area of ​​the guide bar perpendicular to the central axis of the rotor core is Sr, and the height He of the end ring at any position is proportional to the cross-sectional area Sr of the guide bar at that position.

[0013] Preferably, the end face of the end ring is a smoothly transitioning arc surface along the circumferential direction.

[0014] Preferably, under the same pole, the axial height of the end ring is different at different positions in the circumferential direction.

[0015] Preferably, the outer diameter of the end ring is Deo, the inner diameter of the end ring is Dei, the outer diameter of the rotor core is Dr, and the inner diameter of the rotor core is Dsft.

[0016] Preferably, the axial height of the end ring decreases along the direction from the D-axis to the Q-axis.

[0017] Preferably, in the current loop, the total cross-sectional area of ​​the cast aluminum tank is ∑S r ×2, on the longitudinal section passing through the central axis of the rotor core, the single-sided longitudinal cross-sectional area of ​​the end ring is Se.

[0018] Preferably, the end ring is symmetrical about the Q-axis.

[0019] Preferably, the angle between the longitudinal section of the end ring and the Q axis is deg, and the relationship between the axial height He of the end ring and deg is:

[0020] When 0°≤deg<18°, the per-unit value of He is 0.4~0.85;

[0021] When 18°≤deg<36°, the per-unit value of He is 0.5~0.9;

[0022] When 36°≤deg<54°, the per-unit value of He is 0.6~1.1;

[0023] When 54°≤deg<72°, the per-unit value of He is 0.75~1.2;

[0024] When 72°≤deg≤90°, the per-unit value of He is 0.8~1.

[0025] Preferably, on a cross-section perpendicular to the central axis of the rotor core, the magnetic barrier slot includes a D-axis magnetic barrier slot, which includes a cast aluminum slot and a non-cast aluminum slot. The cast aluminum slot is located at both ends of the non-cast aluminum slot, and the cast aluminum slot and the non-cast aluminum slot are separated by an inner magnetic bridge.

[0026] Preferably, the magnetic barrier groove includes a Q-axis magnetic barrier groove, which includes a cast aluminum groove.

[0027] Preferably, the cross section passing through the central axis of the rotor core intersects with the end face of the end ring to form a straight segment, and the straight segment has the same axial height on the rotor core.

[0028] According to another aspect of this application, a self-starting synchronous reluctance motor is provided, including a motor rotor, which is the motor rotor described above.

[0029] The motor rotor provided in this application includes a rotor core and end rings disposed at both ends of the rotor core. Magnetic barrier slots are provided on the rotor core, including cast aluminum slots. Conductor bars are disposed within the cast aluminum slots. The end rings are connected to at least a portion of the conductor bars to form a circuit. On a longitudinal section passing through the central axis of the rotor core, the longitudinal cross-sectional area of ​​one side of the end ring is Se, and the cross-sectional area of ​​the conductor bars perpendicular to the central axis of the rotor core is Sr. The longitudinal cross-sectional area Se of the end ring at any position is proportional to the cross-sectional area Sr of the conductor bars at the point where the circuit is formed with the end ring. The proportionality between the longitudinal cross-sectional area Se of the end ring at any position and the cross-sectional area of ​​the conductor bars at that position ensures that the longitudinal cross-sectional area of ​​the end ring matches the cross-sectional area of ​​the conductor bars. Since the longitudinal cross-sectional area of ​​the end ring and the cross-sectional area of ​​the conductor bars forming the circuit are comparable, their resistances are also comparable. Therefore, when current flows from the conductor bars to the end ring, there is no sudden change in resistance, effectively improving torque pulsation caused by sudden changes in resistance and enhancing the starting capability of the motor. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a motor rotor according to an embodiment of this application;

[0031] Figure 2 This is a schematic diagram of the rotor core structure of an electric motor rotor according to one embodiment of this application;

[0032] Figure 3 This is a schematic diagram of the rotor current circuit of an electric motor rotor according to an embodiment of this application;

[0033] Figure 4 This is a schematic diagram of the rotor current circuit of an electric motor rotor according to an embodiment of this application;

[0034] Figure 5This is a schematic diagram of the rotor current circuit of an electric motor rotor according to an embodiment of this application;

[0035] Figure 6 This is a schematic diagram of the structure of a motor rotor according to an embodiment of this application;

[0036] Figure 7 This is a schematic diagram of the rotor current circuit of an electric motor rotor according to an embodiment of this application;

[0037] Figure 8 This is a schematic diagram of the end face cross-sectional area of ​​a motor rotor according to an embodiment of this application;

[0038] Figure 9 This is a schematic diagram of the magnetic barrier slot structure of a motor rotor according to an embodiment of this application;

[0039] Figure 10 This is a comparison diagram of the starting capabilities of a motor rotor according to an embodiment of this application and a motor rotor of related technologies.

[0040] The reference numerals in the attached figures are as follows:

[0041] 1. Rotor core; 2. Q-axis magnetic barrier slot; 3. D-axis magnetic barrier slot; 4. Central shaft hole; 5. Cast aluminum slot; 6. Non-cast aluminum slot; 7. End ring; 8. Inner magnetic bridge; 9. Conductor bar. Detailed Implementation

[0042] See also Figures 1 to 10 As shown in the embodiment of this application, the motor rotor includes a rotor core 1 and end rings 7 disposed at both ends of the rotor core 1. The rotor core 1 has magnetic barrier slots, including cast aluminum slots 5. Guide bars 9 are disposed within the cast aluminum slots 5. The end rings 7 are connected to at least a portion of the guide bars 9 to form a loop. On a longitudinal section passing through the central axis of the rotor core 1, the single-sided longitudinal cross-sectional area of ​​the end ring 7 is Se, and the cross-sectional area of ​​the guide bar 9 perpendicular to the central axis of the rotor core 1 is Sr. The longitudinal cross-sectional area Se of the end ring 7 at any position is proportional to the cross-sectional area Sr of the guide bar 9 at the point where the loop is formed with the end ring 7. Here, "forming a loop" means that, viewed from the rotor lamination cross-section, the electrical angle difference between the end ring 7 and the guide bar 9 is 90°.

[0043] The longitudinal cross-sectional area Se of the end ring 7 of the motor rotor at any position is proportional to the cross-sectional area Sr of the conductor bar 9 at that position. This ensures that the longitudinal cross-sectional area Se of the end ring 7 matches the cross-sectional area Sr of the conductor bar 9. The longitudinal cross-sectional area of ​​the end ring 7 is comparable to the transverse cross-sectional area of ​​the conductor bar 9 that forms the circuit. In other words, the larger the current conduction cross-section of the conductor bar 9, the larger the current conduction cross-section of the end ring 7. With comparable resistance, the current conduction cross-section of the conductor bar 9 and the current conduction cross-section of the end ring 7 are proportional. Therefore, the current conduction cross-section of the conductor bar 9 and the current conduction cross-section of the end ring 7 are always matched. When the current flows from the conductor bar 9 to the end ring 7, there is no sudden change in resistance. This effectively improves the torque pulsation caused by sudden change in resistance and enhances the starting capability of the motor.

[0044] In one embodiment, the end ring 7 is annular, the axial height of the end ring 7 is He, the cross-sectional area of ​​the guide bar 9 perpendicular to the central axis of the rotor core 1 is Sr, and the height He of the end ring 7 at any position is proportional to the cross-sectional area Sr of the guide bar 9 at that position.

[0045] In this embodiment, the end ring 7 is circular, so its radial width is constant. The axial height of the end ring 7 can be adjusted to match the longitudinal cross-sectional area Se of the end ring 7 at any position with the cross-sectional area Sr of the guide bar 9. To ensure this match, the height He of the end ring 7 at any position must follow the change in the cross-sectional area Sr of the guide bar 9 at that position. In other words, the height He of the end ring 7 at any position is proportional to the cross-sectional area Sr of the guide bar 9 at that position. This ensures that there is no sudden change in resistance when current flows from the guide bar 9 to the end ring 7, effectively improving torque pulsation caused by sudden resistance changes and enhancing the motor's starting capability.

[0046] In this embodiment, the conductor strip 9 is formed of a conductive but non-magnetic material filled into the cast aluminum groove 5. All or part of the conductor strip 9 are shorted together by the end ring 7 to form a circuit. The conductive but non-magnetic material is, for example, aluminum or copper. The end ring 7 is made of the same conductive but non-magnetic material as the conductor strip 9.

[0047] In one embodiment, the end face of the end ring 7 is a smoothly transitioning arc surface along the circumferential direction. In this embodiment, since the axial height of the end ring 7 needs to be adapted to the cross-sectional area of ​​the guide bar 9, the height of the end ring 7 needs to be adjusted according to the cross-sectional area of ​​the guide bar 9. For reluctance motors, the cast aluminum area of ​​different magnetic barrier layers is also different. Therefore, the axial height of the end ring 7 can be adaptively adjusted according to the change in the cross-sectional area of ​​the guide bar 9, which is most advantageous for the forming of the motor rotor. In this case, the height of the end ring 7 can be adjusted according to the change in the cross-sectional area of ​​the guide bar 9, reducing the forming difficulty of the end ring 7. At this time, making the end face of the end ring 7 a smoothly transitioning arc surface along the circumferential direction can further reduce the possibility of resistance sudden change and improve torque pulsation.

[0048] In one embodiment, the cross section passing through the central axis of the rotor core intersects with the end face of the end ring 7 to form a straight segment. The straight segment has the same axial height on the rotor core 1, which can improve the structural regularity of the end ring 7, reduce the design and processing difficulty of the end ring 7, and reduce processing costs.

[0049] In one embodiment, under the same pole, the axial height of the end ring 7 is different at various positions in the circumferential direction. Since the current flows along the circumference of the end ring 7 after entering the end ring 7 from the conductor 9, setting the axial height of the end ring 7 to be different at various positions in the circumferential direction allows the change in the axial height of the end ring 7 in the circumferential direction to better match the change in the cross-sectional area of ​​the conductor 9 in the circumferential direction, further reducing the sudden change in resistance.

[0050] In one embodiment, the outer diameter of the end ring 7 is Deo, the inner diameter of the end ring 7 is Dei, the outer diameter of the rotor core 1 is Dr, and the inner diameter of the rotor core 1 is Dsft. By setting a high ratio between the inner and outer diameters of the end ring 7 and the inner and outer diameters of the rotor core 1, the width of the end ring 7 of the motor rotor can be maximized, thereby more effectively increasing the end ring area and reducing the rotor resistance.

[0051] In one embodiment, the axial height of the end ring 7 decreases along the direction from the D-axis to the Q-axis, and the axial height of the guide bar 9 in the D-axis direction decreases along the direction from the D-axis to the Q-axis, ensuring stable starting torque during rotor rotation.

[0052] In one embodiment, the total cross-sectional area of ​​the cast aluminum groove 5 in the current loop is ∑S r ×2, on the longitudinal section passing through the central axis of rotor core 1, the single-sided longitudinal cross-sectional area of ​​end ring 7 is Se.

[0053] The conductor bars 9 are symmetrically arranged in the current loop. The sum of the cross-sectional areas of the conductor bars 9 is ∑Sr×2, and the cross-sectional area of ​​the end ring is Se. The ratio of the two is within the above range, which can ensure that the loop resistance is small and the motor starting capability is strong.

[0054] Along the direction from the D-axis to the Q-axis, the cross-sectional areas of the guide bar 9 are Sr1, Sr2, Sr3, ..., where the cross-sectional area of ​​the guide bar 9 in the Q-axis magnetic barrier groove located on the Q-axis is Srn, and ∑Sr=Sr1+Sr2+……+Srn.

[0055] In one embodiment,

[0056] In one embodiment, the end ring 7 is symmetrical about the Q-axis and the guide bar 9 is symmetrical about the Q-axis, which makes both the end ring 7 and the guide bar 9 of the motor form a symmetrical structure, thereby providing a more uniform resistance change and further reducing the possibility of sudden resistance changes.

[0057] In one embodiment, the angle between the longitudinal section of the end ring 7 and the Q axis is deg, and the relationship between the axial height He of the end ring 7 and deg is as follows:

[0058] When 0°≤deg<18°, the per-unit value of He is 0.4~0.85;

[0059] When 18°≤deg<36°, the per-unit value of He is 0.5~0.9;

[0060] When 36°≤deg<54°, the per-unit value of He is 0.6~1.1;

[0061] When 54°≤deg<72°, the per-unit value of He is 0.75~1.2;

[0062] When 72°≤deg≤90°, the per-unit value of He is 0.8~1.

[0063] By limiting the above, the axial height of the lower ring 7 at different positions can be constrained, thereby ensuring that the resistance change of the motor rotor is relatively small at different times, and there is no sudden change in resistance, thus improving the starting capability of the motor.

[0064] In one embodiment, on a cross section perpendicular to the central axis of the rotor core 1, the magnetic barrier slot includes a D-axis magnetic barrier slot 3, which includes a cast aluminum slot 5 and a non-cast aluminum slot 6. The cast aluminum slot 5 is located at both ends of the non-cast aluminum slot 6, and the cast aluminum slot 5 and the non-cast aluminum slot 6 are separated by an inner magnetic bridge 8.

[0065] In one embodiment, the magnetic barrier groove includes a Q-axis magnetic barrier groove 2, which is a cast aluminum groove 5.

[0066] In this embodiment, the channel formed between adjacent D-axis magnetic barrier slots 3 is a magnetic channel, which can form a magnetic circuit channel during the operation of the motor, allowing magnetic lines of force to flow through.

[0067] The rotor core 1 has multiple sets of identical air slots as magnetic barrier slots, and the number of air slot sets is the same as the number of rotor poles. Each set of air slots is divided into multiple layers along the Q-axis. Each layer of air slots is adjacent to the magnetic channel along the Q-axis, and the outermost edge along the D-axis is the outer magnetic bridge, which is adjacent to the air gap.

[0068] See also Figure 10 As shown, after adopting the end ring 7 of this application embodiment, the starting capability of the motor is increased from 3.5 to 8.5 compared with the starting capability of the motor using the conventional end ring in the related technology, and the starting capability is increased to 5, which is an increase of 143%. Therefore, the starting capability of the motor is greatly improved.

[0069] According to an embodiment of this application, the self-starting synchronous reluctance motor includes a motor rotor, which is the motor rotor described above.

[0070] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0071] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A motor rotor, characterized in that, The device includes a rotor core (1) and end rings (7) disposed at both ends of the rotor core (1). The rotor core (1) is provided with magnetic barrier grooves, the magnetic barrier grooves include cast aluminum grooves (5), and guide bars (9) are disposed in the cast aluminum grooves (5). The end rings (7) are connected to at least part of the guide bars (9) to form a loop. On the longitudinal section passing through the central axis of the rotor core (1), the longitudinal cross-sectional area of ​​the end rings (7) on one side is Se, and the cross-sectional area of ​​the guide bars (9) perpendicular to the central axis of the rotor core (1) is Sr. The longitudinal cross-sectional area Se of the end rings (7) at any position is proportional to the cross-sectional area Sr of the guide bars (9) at the point where they form a loop with the end rings (7). The end ring (7) is a circular ring, the axial height of the end ring (7) is He, the cross-sectional area of ​​the guide bar (9) perpendicular to the central axis of the rotor core (1) is Sr, and the height He of the end ring (7) at any position is proportional to the cross-sectional area Sr of the guide bar (9) at that position. The axial height of the end ring (7) decreases along the direction from the D axis to the Q axis.

2. The motor rotor according to claim 1, characterized in that, The end face of the end ring (7) is a smoothly transitioned arc surface along the circumferential direction.

3. The motor rotor according to claim 1, characterized in that, Under the same pole, the axial height of the end ring (7) is different at different positions in the circumferential direction.

4. The motor rotor according to claim 1, characterized in that, The outer diameter of the end ring (7) is Deo, the inner diameter of the end ring (7) is Dei, the outer diameter of the rotor core (1) is Dr, and the inner diameter of the rotor core (1) is Dsft. ; .

5. The motor rotor according to claim 1, characterized in that, In the current loop, the total cross-sectional area of ​​the cast aluminum groove (5) is On the longitudinal section passing through the central axis of the rotor core (1), the single-sided longitudinal cross-sectional area of ​​the end ring (7) is Se. .

6. The motor rotor according to claim 1, characterized in that, The end ring (7) is symmetrical about the Q axis.

7. The motor rotor according to claim 1, characterized in that, The angle between the longitudinal section of the end ring (7) and the Q axis is deg, and the relationship between the axial height He of the end ring (7) and deg is as follows: When 0°≤deg<18°, the per-unit value of He is 0.4~0.85; When 18°≤deg<36°, the per-unit value of He is 0.5~0.9; When 36°≤deg<54°, the per-unit value of He is 0.6~1.1; When 54°≤deg<72°, the per-unit value of He is 0.75~1.2; When 72°≤deg≤90°, the per-unit value of He is 0.8~1.

8. The motor rotor according to claim 1, characterized in that, On a cross section perpendicular to the central axis of the rotor core (1), the magnetic barrier groove includes a D-axis magnetic barrier groove (3), the D-axis magnetic barrier groove (3) includes the cast aluminum groove (5), the D-axis magnetic barrier groove (3) also includes a non-cast aluminum groove (6), the cast aluminum groove (5) is located at both ends of the non-cast aluminum groove (6), and the cast aluminum groove (5) and the non-cast aluminum groove (6) are separated by an inner magnetic bridge (8).

9. The motor rotor according to claim 1, characterized in that, The magnetic barrier groove includes a Q-axis magnetic barrier groove (2), and the Q-axis magnetic barrier groove (2) includes a cast aluminum groove (5).

10. The motor rotor according to claim 2, characterized in that, The cross section passing through the central axis of the rotor core intersects with the end face of the end ring (7) to form a straight segment, and the straight segment has the same axial height on the rotor core (1).

11. A self-starting synchronous reluctance motor, comprising a motor rotor, characterized in that, The motor rotor is the motor rotor according to any one of claims 1 to 10.

Images