Electric machine rotor and method of manufacturing thereof and self-starting synchronous reluctance machine

Abstract

The application provides a motor rotor, a manufacturing method thereof and a self-starting synchronous reluctance motor. The motor rotor comprises a rotor core (1), the rotor core (1) is provided with a magnetic barrier slot and a center shaft hole (4), the magnetic barrier slot comprises a Q-axis magnetic barrier slot (2) located at the outermost side of a Q-axis and a D-axis magnetic barrier slot (3) located between the Q-axis magnetic barrier slot (2) and the center shaft hole (4) and extending along a D-axis direction, the D-axis magnetic barrier slot (3) comprises a non-cast aluminum area (6) and cast aluminum areas (5) located at both ends of the non-cast aluminum area (6), the Q-axis magnetic barrier slot (2) and the cast aluminum areas (5) are filled with conductive non-magnetic material, and the cast aluminum areas (5) and the non-cast aluminum area (6) are communicated. According to the motor rotor, rotor magnetic leakage can be reduced, the salient pole ratio can be improved, and the motor efficiency can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric machines, in particular to an electric machine rotor, a manufacturing method thereof and a self-starting synchronous reluctance electric machine. BACKGROUND

[0002] The direct-start synchronous reluctance electric machine combines the structural features of induction electric machines and synchronous reluctance electric machines, generates torque through a squirrel cage to achieve starting, generates reluctance torque through a rotor inductance gap to achieve constant-speed operation, and can be directly connected to a power supply to achieve starting and operation. Compared with direct-start permanent magnet electric machines, the direct-start synchronous reluctance electric machine does not use rare earth permanent magnet materials and has no demagnetization problem, has low cost and good reliability. Compared with asynchronous electric machines, the direct-start synchronous reluctance electric machine has high efficiency and constant speed. The direct-start synchronous reluctance electric machine can self-start without a controller, further reducing the cost.

[0003] The self-starting electric machine generates starting torque by cutting the stator magnetic field with rotor bars, the rotor bars are electrically conductive and magnetically non-conductive materials, usually pure aluminum, and are filled by high-pressure casting. After casting aluminum, end rings are formed at both ends of the rotor, short-circuiting all or part of the bars.

[0004] The rotor core is provided with a plurality of groups of identical air slots, and the number of groups of air slots is equal to the number of rotor poles; according to the shape of the air slots, the radial direction parallel to the air slots is referred to as the D-axis, and the radial direction perpendicular to the air slots is referred to as the Q-axis; the air slots are divided into multiple layers along the Q-axis; each layer of air slots is divided into D-axis aluminum casting slots, Q-axis aluminum casting slots, and non-aluminum casting slots; the aluminum casting slots and the non-aluminum casting slots are separated by an inner magnetic bridge; the air slots and the outer circle of the rotor are separated by an outer magnetic bridge.

[0005] The rotor is provided with a plurality of groups of slots, so the structural strength of the rotor is generally low, and only the outer magnetic bridge cannot meet the structural strength requirement of the electric machine when rotating at high speed. On the other hand, the magnetic bridge is also used to limit the flow direction of the aluminum liquid during casting to ensure the shape of the bars. However, the magnetic lines will form a magnetic leakage path through the magnetic bridge, affecting the salient pole ratio and reducing the efficiency of the electric machine. SUMMARY

[0006] Therefore, the technical problem to be solved by the present application is to provide an electric machine rotor, a manufacturing method thereof and a self-starting synchronous reluctance electric machine, which can reduce rotor leakage, improve the salient pole ratio and improve the efficiency of the electric machine.

[0007] To solve the above problems, the present application provides an electric machine rotor, comprising a rotor core, a magnetic barrier slot and a center shaft hole are arranged on the rotor core, the magnetic barrier slot comprises a Q-axis magnetic barrier slot located at the outermost side of the Q-axis and a D-axis magnetic barrier slot extending along the D-axis direction between the Q-axis magnetic barrier slot and the center shaft hole, the D-axis magnetic barrier slot comprises a non-aluminum casting area and aluminum casting areas located at both ends of the non-aluminum casting area, the Q-axis magnetic barrier slot and the aluminum casting area are filled with electrically conductive and magnetically non-conductive materials, and the aluminum casting area and the non-aluminum casting area are in communication.

[0008] Preferably, end rings are provided at both ends of the rotor core along the axial direction, and the end rings are connected to the conductive but non-magnetic material in the cast aluminum region to form short-circuit rings.

[0009] Preferably, the end ring at the corresponding position of each D-axis magnetic barrier groove is symmetrical about the Q-axis, the interval between the inner rings of the end rings corresponding to a single D-axis magnetic barrier groove along the direction parallel to the D-axis is 2Len, and the interval between the two cast aluminum regions of the D-axis magnetic barrier groove along the direction parallel to the D-axis is 2Ln, Len≥Ln, where n is the layer number of the D-axis magnetic barrier groove along the Q-axis starting from the D-axis.

[0010] Preferably, the outer diameter of the rotor core is Dr, and the spacing 2Len between the inner rings of the end rings corresponding to the D-axis magnetic barrier slots in each layer, along the direction parallel to the D-axis, satisfies...

[0011] Preferably, the outer diameter of the rotor core is Dr, and the spacing between the two cast aluminum regions of the magnetic barrier slot on the D-axis along the direction parallel to the D-axis is 2Ln, where Ln satisfies

[0012] Preferably, the height of the rotor core is H, and the axial height of the end ring is HT.

[0013] Preferably, the diameter of the central shaft hole is Dsft, the outer diameter of the rotor core is Dr, and the outer diameter of the end ring is D. and

[0014] Preferably, an outer magnetic bridge is provided on the outer periphery of the magnetic barrier groove.

[0015] 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.

[0016] According to another aspect of this application, a method for manufacturing the above-mentioned motor rotor is provided, comprising:

[0017] Machining rotor laminations with Q-axis magnetic barrier grooves and D-axis magnetic barrier grooves;

[0018] The rotor laminations are stacked to form the rotor core;

[0019] Insert the support fixture into the non-cast aluminum region of the D-axis magnetic barrier slot of the rotor core, and align the edge of the support fixture with the edge of the cast aluminum region of the D-axis magnetic barrier slot.

[0020] The cast aluminum region of the rotor core is filled with a conductive but non-magnetic material, and end rings are formed at both ends of the rotor core. The support fixture is located on the inner side of the inner circumference of the end rings.

[0021] Remove the support fixture.

[0022] Preferably, the conductive but non-magnetic material is aluminum or copper.

[0023] The motor rotor provided in this application includes a rotor core with magnetic barrier slots and a central shaft hole. The magnetic barrier slots include a Q-axis magnetic barrier slot located on the outermost side of the Q-axis and a D-axis magnetic barrier slot located between the Q-axis magnetic barrier slot and the central shaft hole and extending along the D-axis. The D-axis magnetic barrier slot includes a non-cast aluminum region and cast aluminum regions located at both ends of the non-cast aluminum region. The Q-axis magnetic barrier slots and the cast aluminum regions are filled with a conductive but non-magnetic material, and the cast aluminum regions and non-cast aluminum regions are connected. This motor rotor divides the D-axis magnetic barrier slots of the rotor core into cast aluminum and non-cast aluminum regions, and fills the cast aluminum regions with a conductive but non-magnetic material, thus connecting the cast aluminum and non-cast aluminum regions. This eliminates the internal magnetic bridge between the cast aluminum and non-cast aluminum regions, forming a motor rotor without internal magnetic bridges, effectively reducing rotor leakage flux, increasing the rotor salient pole ratio, and improving motor efficiency and performance. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a motor rotor after removing the end ring according to an embodiment of this application;

[0025] Figure 2 This is a schematic diagram of the structure of a motor rotor according to an embodiment of this application;

[0026] Figure 3 This is a schematic diagram of the rotor core structure of an electric motor rotor according to one embodiment of this application;

[0027] Figure 4 This is a longitudinal cross-sectional view of a motor rotor according to an embodiment of this application;

[0028] Figure 5 The starting capability curve of the motor rotor with 2Ln / Dr is shown in one embodiment of this application.

[0029] Figure 6 This is a comparison chart of the efficiency of a motor rotor according to one embodiment of this application and a motor rotor with an internal magnetic bridge.

[0030] The reference numerals in the attached figures are as follows:

[0031] 1. Rotor core; 2. Q-axis magnetic barrier slot; 3. D-axis magnetic barrier slot; 4. Central shaft hole; 5. Cast aluminum zone; 6. Non-cast aluminum zone; 7. End ring. Detailed Implementation

[0032] See also Figures 1 to 6As shown, according to an embodiment of this application, the motor rotor includes a rotor core 1, on which magnetic barrier grooves and a central shaft hole 4 are provided. The magnetic barrier grooves include a Q-axis magnetic barrier groove 2 located on the outermost side of the Q-axis and a D-axis magnetic barrier groove 3 located between the Q-axis magnetic barrier groove 2 and the central shaft hole 4 and extending along the D-axis direction. The D-axis magnetic barrier groove 3 includes a non-cast aluminum region 6 and cast aluminum regions 5 located at both ends of the non-cast aluminum region 6. The Q-axis magnetic barrier groove 2 and the cast aluminum region 5 are filled with a conductive but non-magnetic material, and the cast aluminum region 5 and the non-cast aluminum region 6 are connected.

[0033] The material filled in the cast aluminum region 5 in this application is a conductive but non-magnetic material. The cast aluminum region 5 is only a name for the filling region and does not limit the filling material. Any conductive but non-magnetic material that can be used as a conductor can be filled into the cast aluminum region 5. For example, the conductive but non-magnetic material is aluminum or copper.

[0034] The motor rotor divides the D-axis magnetic barrier slot 3 of the rotor core 1 into a cast aluminum region 5 and a non-cast aluminum region 6. The cast aluminum region 5 is filled with a conductive but non-magnetic material, which connects the cast aluminum region 5 and the non-cast aluminum region 6. This removes the internal magnetic bridge between the cast aluminum region 5 and the non-cast aluminum region 6, forming a motor rotor without internal magnetic bridges. This effectively reduces rotor leakage magnetism, increases the rotor salient pole ratio, and improves motor efficiency and performance.

[0035] Because the motor rotor in this application does not have an internal magnetic bridge, the shape of the rotor bars formed by the conductive and non-magnetic material and the end rings 7 at both ends can be flexibly adjusted, enabling the motor's starting capability to be optimized and improving its starting performance. (See also...) Figure 6 As shown, compared to a motor with an internal magnetic bridge, the performance of the motor without an internal magnetic bridge in this application embodiment is improved by at least 1%.

[0036] Furthermore, since the inner magnetic bridge is eliminated, the filling material in the cast aluminum zone 5 can be used to replace the function of the inner magnetic bridge, which can significantly increase the structural strength of the motor rotor.

[0037] In one embodiment, end rings 7 are provided at both ends of the rotor core 1 along the axial direction. The end rings 7 are connected to the conductive but non-magnetic material in the cast aluminum region 5 to form short-circuit rings.

[0038] In this embodiment, since no internal magnetic bridge is provided, a tooling is needed to replace the internal magnetic bridge during aluminum casting. After aluminum casting is completed, the tooling is removed, resulting in a motor rotor without an internal magnetic bridge. To facilitate the removal of the tooling after aluminum casting, the end ring 7 needs to have a clearance hole at the location where the tooling is installed, so that the tooling can be removed from the clearance hole. After the tooling is removed, a clearance hole will be left on the end ring 7, which will connect with the space left after the tooling is removed from the rotor core 1 to form a heat dissipation channel. This can improve the heat dissipation capacity of the rotor core 1, reduce the amount of material used, make the motor lighter, and reduce costs.

[0039] The channel formed between adjacent D-axis magnetic barrier slots 3 is a magnetic channel, which can form a magnetic circuit channel during motor operation, allowing magnetic lines of force to flow through.

[0040] 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, and each layer of air slots contains only one slot. 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.

[0041] In one embodiment, the end ring 7 at the corresponding position of each D-axis magnetic barrier groove 3 is symmetrical about the Q-axis, the spacing between the inner rings of the end ring 7 corresponding to a single D-axis magnetic barrier groove 3 along the direction parallel to the D-axis is 2Len, and the spacing between the two cast aluminum regions 5 of the D-axis magnetic barrier groove 3 along the direction parallel to the D-axis is 2Ln, where Len≥Ln, and n is the layer number of the D-axis magnetic barrier groove 3 along the Q-axis direction starting from the D-axis.

[0042] In this embodiment, the end ring 7 is a ring structure. Since the tooling serves as the boundary of the cast aluminum region 5, in order to ensure that the end ring 7 does not interfere with the removal of the tooling, the distance between the inner ring of the end ring 7 corresponding to the position of the D-axis magnetic barrier groove 3 and the Q-axis should be greater than the distance between the boundary of the cast aluminum region 5 of the D-axis magnetic barrier groove 3 and the Q-axis, that is, Len≥Ln, so as to leave enough clearance space.

[0043] In one embodiment, the outer diameter of the rotor core 1 is Dr, and the spacing 2Len between the inner rings of the end rings 7 corresponding to the D-axis magnetic barrier slots 3 in each layer, along the direction parallel to the D-axis, satisfies... by Figure 2 For example, Len should satisfy

[0044] The outer diameter of the rotor core 1 is Dr, and the spacing between the two cast aluminum regions 5 of the magnetic barrier slot 3 along the direction parallel to the D-axis is 2Ln, where Ln satisfies by Figure 2 For example, Ln should satisfy This ensures that the cast aluminum zone 5 has sufficient width to meet the motor's self-starting requirements and improve the motor's self-starting capability.

[0045] When designing the cast aluminum zone 5, a large width of the cast aluminum zone 5 can ensure that the motor has a good starting capability, but if it is too large, it will cause the eddy currents of the aluminum conductor bar and end ring 7 to increase at synchronous speed, reduce motor efficiency, aggravate heat generation, and reduce the rotor ventilation area, which will further aggravate heat generation. If the width of the cast aluminum zone is too small, the motor starting capability will be poor and it will not be able to reach synchronous speed. Considering both aspects, limiting this range can achieve the best effect.

[0046] In one embodiment, the height of the rotor core 1 is H, and the axial height of the end ring 7 is HT. This allows the end ring 7 to have sufficient axial height, which can reduce resistance and improve starting capability.

[0047] In one embodiment, the diameter of the central shaft hole 4 is Dsft, the outer diameter of the rotor core 1 is Dr, and the outer diameter of the end ring 7 is D. and This ensures that the end ring 7 is located within the outer circumference of the rotor core 1 and the central shaft hole 4, preventing the end ring 7 from exceeding the range of the rotor core 1.

[0048] In one embodiment, an outer magnetic bridge is provided on the outer periphery of the magnetic barrier groove, which can improve the structural strength of the rotor core 1.

[0049] According to an embodiment of this application, the self-starting synchronous reluctance motor includes a motor rotor, which is the motor rotor described above.

[0050] According to an embodiment of this application, the above-mentioned method for manufacturing a motor rotor includes: processing rotor laminations having Q-axis magnetic barrier slots 2 and D-axis magnetic barrier slots 3; stacking the rotor laminations into a rotor core 1; inserting a support fixture into the non-cast aluminum region 6 of the D-axis magnetic barrier slot 3 of the rotor core 1, such that the edge of the support fixture is aligned with the edge of the cast aluminum region 5 of the D-axis magnetic barrier slot 3; filling the cast aluminum region 5 of the rotor core 1 with a conductive but non-magnetic material, and forming end rings 7 at both ends of the rotor core 1, with the support fixture located on the inner side of the inner circumference of the end rings 7; and removing the support fixture.

[0051] In this embodiment, the supporting fixture serves to replace the inner magnetic bridge in the casting process to restrict the flow of conductive and non-magnetic materials, and to separate the cast aluminum area 5 and the non-cast aluminum area 6. In this embodiment, the conductive and non-magnetic materials are filled into the D-axis magnetic barrier groove 3, and each layer of D-axis magnetic barrier groove 3 is filled only with conductive and non-magnetic materials in the cast aluminum area 5 at both ends along the D-axis direction, while the non-cast aluminum area 6 between the two ends of the cast aluminum area 5 is still air.

[0052] The conductive but non-magnetic material is aluminum or copper.

[0053] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0054] 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 rotor core (1) is provided with a magnetic barrier groove and a central shaft hole (4). The magnetic barrier groove includes a Q-axis magnetic barrier groove (2) located on the outermost side of the Q-axis and a D-axis magnetic barrier groove (3) located between the Q-axis magnetic barrier groove (2) and the central shaft hole (4) and extending along the D-axis direction. The D-axis magnetic barrier groove (3) includes a non-cast aluminum region (6) and cast aluminum regions (5) located at both ends of the non-cast aluminum region (6). The Q-axis magnetic barrier groove (2) and the cast aluminum region (5) are filled with a conductive but non-magnetic material. The cast aluminum region (5) and the non-cast aluminum region (6) are connected. The rotor core (1) is provided with end rings (7) at both ends of the axial direction. The end rings (7) are connected to the conductive and non-magnetic material in the cast aluminum region (5) to form a short-circuit ring. The end ring (7) at the corresponding position of each D-axis magnetic barrier groove (3) is symmetrical about the Q-axis. The spacing between the inner rings of the end ring (7) corresponding to a single D-axis magnetic barrier groove (3) along the direction parallel to the D-axis is 2Len, where n is the layer number of the D-axis magnetic barrier groove (3) along the Q-axis starting from the D-axis. The outer diameter of the rotor core (1) is Dr, and the spacing 2Len between the inner rings of the end rings (7) corresponding to the D-axis magnetic barrier slots (3) in each layer along the direction parallel to the D-axis satisfies the following condition.

2. The motor rotor according to claim 1, characterized in that, The interval between the two cast aluminum zones (5) of the magnetic barrier groove (3) along the direction parallel to the D axis is 2Ln, Len≥Ln.

3. The motor rotor according to claim 1, characterized in that, The spacing between the two cast aluminum regions (5) of the D-axis magnetic barrier groove (3) along the direction parallel to the D-axis is 2Ln, where Ln satisfies 4. The motor rotor according to claim 1, characterized in that, The height of the rotor core (1) is H, and the axial height of the end ring (7) is HT.

5. The motor rotor according to claim 1, characterized in that, The diameter of the central shaft hole (4) is Dsft, and the outer diameter of the end ring (7) is D. and 6. The motor rotor according to claim 1, characterized in that, An external magnetic bridge is provided on the outer periphery of the magnetic barrier groove.

7. 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 6.

8. A method for manufacturing a motor rotor as described in any one of claims 1 to 6, characterized in that, include: Machining rotor laminations with Q-axis magnetic barrier grooves (2) and D-axis magnetic barrier grooves (3); The rotor laminations are stacked to form the rotor core (1); Insert the support fixture into the non-cast aluminum region (6) of the D-axis magnetic barrier groove (3) of the rotor core (1), and align the edge of the support fixture with the edge of the cast aluminum region (5) of the D-axis magnetic barrier groove (3). The cast aluminum region (5) of the rotor core (1) is filled with conductive and non-magnetic material, and end rings (7) are formed at both ends of the rotor core (1). The support fixture is located on the inner side of the inner circumference of the end rings (7). Remove the support fixture.

9. The manufacturing method according to claim 8, characterized in that, The conductive but non-magnetic material is aluminum or copper.

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