Rotor for switched reluctance motor and switched reluctance motor

Abstract

The utility model provides a rotor for a switched reluctance motor, and the rotor comprises a supporting member which is provided with a supporting outer surface which is arranged around the central axis of the supporting member, a plurality of grooves which are uniformly distributed in the circumferential direction are formed in the supporting outer surface, the rotor also comprises a plurality of magnetic conductive members, and the magnetic conductive members are arranged in the grooves. The plurality of magnetic conductive components are arranged in the groove, and two adjacent magnetic conductive components in the plurality of magnetic conductive components are separated by a part of the supporting outer surface; each of the plurality of magnetic conductive members is configured such that the magnetic conductivity in the radial direction of the support member is better than the magnetic conductivity in the chordwise direction of the support member, the chordwise direction being perpendicular to the radial direction. The utility model also provides a switched reluctance motor comprising the rotor. According to the invention, the torque generation capability of the switched reluctance motor can be improved.

Description

Technical Field

[0001] This application relates to the field of motor technology, and more particularly to a rotor for a switched reluctance motor and a switched reluctance motor including such a rotor. Background Technology

[0002] A switched reluctance motor (SRM) is a type of motor that operates based on the principle that magnetic flux always closes along the path of least magnetic reluctance. During operation, when the rotor salient poles are misaligned with the stator salient poles, a magnetic reluctance force acts on the rotor, generating a reluctance torque, causing the rotor to rotate to the position of minimum magnetic reluctance.

[0003] Generally, a rotor includes a rotor core with outwardly protruding rotor teeth (i.e., rotor salient poles), with rotor slots formed between adjacent rotor teeth, but no rotor windings are installed within the rotor slots. The stator includes a stator core with inwardly protruding stator teeth, with stator slots formed between adjacent stator teeth, and stator windings are installed within the stator slots. The stator windings, as excitation windings providing the working magnetic field, define the stator salient poles. By controlling the opening and closing of each stator winding, a magnetic reluctance force can be applied to the corresponding rotor salient pole, driving the rotor to rotate. Based on this structure, switched reluctance motors have advantages such as simple structure, high mechanical strength, low cost, and high reliability, and have been widely used in household appliances, power tools, and electric vehicles.

[0004] During the operation of a switched reluctance motor, the motor's reluctance is minimized when the rotor salient poles are aligned with the stator salient poles, resulting in maximum inductance. Conversely, the motor's reluctance is maximized when the rotor and stator salient poles are misaligned, minimizing inductance. Therefore, if current is supplied to the corresponding excitation winding during the inductance rise phase, effective torque will be generated on the rotor. In other words, the slope of the inductance change and the current value directly affect the motor's torque generation capability. However, in existing switched reluctance motors, the slope of the inductance change is relatively small, thus limiting the motor's torque generation capability.

[0005] Therefore, it is hoped that existing switched reluctance motors can be improved to further enhance the motor's torque generation capability, thereby improving motor efficiency and reducing motor cost. Utility Model Content

[0006] The purpose of this application is to provide an improved rotor for a switched reluctance motor and a switched reluctance motor including such a rotor, in order to overcome at least one of the above-mentioned technical problems.

[0007] Therefore, according to one aspect of this application, a rotor for a switched reluctance motor is provided, comprising: a support member having a support outer surface disposed around a central axis of the support member, wherein a plurality of grooves are formed on the support outer surface and evenly distributed circumferentially, wherein the rotor further comprises a plurality of magnetically conductive members disposed in the grooves, and adjacent pairs of the plurality of magnetically conductive members are separated by a portion of the support outer surface, wherein each of the plurality of magnetically conductive members is configured to have better magnetic permeability in the radial direction of the support member than in the chordal direction of the support member, the chordal direction being perpendicular to the radial direction.

[0008] According to one embodiment of this application, the magnetic conductive member is formed by stacking multiple grain-oriented silicon steel sheets, and the magnetic conductive member is arranged such that the rolling direction of each grain-oriented silicon steel sheet is consistent with the radial direction.

[0009] According to one embodiment of this application, the magnetically conductive outer surface of the magnetically conductive member and a portion of the supporting outer surface form a smooth circumferential outer surface.

[0010] According to one embodiment of this application, the magnetically conductive member further has an inner surface projecting toward the central axis.

[0011] According to one embodiment of this application, the inner surface has a V-shaped surface, an arc-shaped surface, or a stepped surface extending in a direction parallel to the central axis.

[0012] According to one embodiment of this application, the magnetically conductive member further has a side surface located between the magnetically conductive outer surface and the inner surface, the side surface extending a predetermined distance along the radial direction.

[0013] According to one embodiment of this application, the magnetically conductive component is bonded, welded, or embedded in the groove.

[0014] According to one embodiment of this application, the support member is non-magnetic.

[0015] According to another aspect of this application, a switched reluctance motor is provided, comprising: a rotor as described above; and a stator that houses the rotor and includes: a stator core having a plurality of stator teeth extending toward the central axis of the rotor, wherein adjacent two of the plurality of stator teeth form stator slots; and a stator winding disposed within the stator slots and configured to generate a magnetic field when energized, the magnetic field acting on the magnetic conductors of the rotor.

[0016] According to one embodiment of this application, the stator winding is divided into multiple phases, and the stator windings in each phase are configured to be energized and de-energized at different times.

[0017] The rotor and switched reluctance motor provided in this application can further increase the slope of the motor's inductance change, improve the motor's torque generation capability, and thus improve motor efficiency. Furthermore, with the increase in motor torque generation capability, the design dimensions of related motor components can be reduced accordingly, thereby lowering motor costs. Attached Figure Description

[0018] Exemplary embodiments of this application will now be described in detail with reference to the accompanying drawings. It should be understood that the embodiments described below are for illustrative purposes only and are not intended to limit the scope of this application. In the accompanying drawings:

[0019] Figure 1 This is a schematic cross-sectional view of a switched reluctance motor according to an embodiment of this application;

[0020] Figure 2 yes Figure 1 The diagram shows a schematic cross-sectional view of the rotor of a switched reluctance motor.

[0021] Figure 3 yes Figure 2 A schematic diagram of the grain-oriented silicon steel sheet of the magnetic conductive component of the rotor shown.

[0022] Figure 4 yes Figure 1 The diagram shows a schematic cross-sectional view of the stator of a switched reluctance motor. Detailed Implementation

[0023] Preferred embodiments of this application are described in detail below with reference to examples. Those skilled in the art should understand that these exemplary embodiments do not imply any limitation on this application. Furthermore, features in the embodiments of this application can be combined with each other unless otherwise specified. In different drawings, the same components may be represented by the same reference numerals, and other components are omitted for brevity, but this does not mean that the rotor and switched reluctance motor of this application cannot include other components or modules. It should be understood that the dimensions, proportions, and number of components in the drawings are not intended to limit this application.

[0024] The terms “first”, “second”, etc., used in this application are only used to distinguish different objects, and not to describe a specific order.

[0025] The following reference Figures 1 to 4 This application describes the switched reluctance motor and its rotor. For example... Figure 1 As shown, a switched reluctance motor (also referred to as a motor below) 100 (e.g., a hub motor for an electric vehicle) may include a rotor 10 and a stator 20, wherein the stator 20 houses the rotor 10.

[0026] like Figure 1 and Figure 4 As shown, the stator 20 includes a stator core 21 and a stator winding 24. The stator core 21 has a plurality of stator teeth 22 extending toward the central axis O of the stator 21 (it should be noted that this axis may coincide with the central axis of the rotor 10, therefore the central axis of the rotor 10 may also be referred to as "central axis O" herein), and stator slots 23 are formed between adjacent stator teeth 22. The stator winding 24 is disposed within the stator slots 23 and configured to generate a magnetic field when energized. Therefore, the stator winding 24 may also be referred to as an excitation winding. As an example, such as Figure 1 and Figure 4 As shown, the stator core 21 has 12 stator teeth 22, correspondingly forming 12 stator slots 23, thereby allowing for the arrangement of 12 stator windings 24. These 12 stator windings 24 can be divided into 3 phases. For example, as... Figure 4 As shown, the four stator windings 24 labeled "A1", "A2", "A3", and "A4" can be referred to as the first phase, the four stator windings 24 labeled "B1", "B2", "B3", and "B4" can be referred to as the second phase, and the four stator windings 24 labeled "C1", "C2", "C3", and "C4" can be referred to as the third phase. Each phase contains stator windings 24 configured to be energized and de-energized at different times, thereby driving the rotor 10 to rotate in a predetermined direction. It should be noted that the stator teeth 22, stator slots 23, and stator windings 24 of the stator 20 are not limited to the number and phases described and shown, but can have different numbers and phases depending on design requirements.

[0027] like Figure 1 and Figure 2 As shown, the rotor 10 may include a support member 11 and a plurality of magnetically conductive members 12. The support member 11 has a supporting outer surface 17 disposed around the central axis of the support member 11 (it should be noted that this axis is also the central axis of the rotor 10, and therefore may also be referred to herein as "central axis O"), and a plurality of grooves 18 uniformly distributed circumferentially are formed on the supporting outer surface 17. For example, Figure 1 and Figure 2 Eight grooves 18 are shown. The support member 11 has a central hole 13, which is configured for fixed connection with the shaft (not shown) of the switched reluctance motor 100. According to one embodiment of this application, the support member 11 is non-magnetic and may be made of, for example, plastic, aluminum alloy, etc.

[0028] Multiple magnetically conductive members 12 are disposed in the groove 18, and adjacent magnetically conductive members 12 are separated by a portion of the supporting outer surface 17. Thus, the rotor 10 has a segmented structure, wherein each magnetically conductive member 12 can form a local magnetic circuit with its corresponding stator tooth, separated by a non-magnetically conductive supporting member 11, rather than forming a magnetic circuit spanning the rotor center and / or other stator teeth as in conventional switched reluctance motors. Therefore, the switched reluctance motor of this application can have a shorter magnetic circuit, thereby improving motor losses.

[0029] According to one embodiment of this application, each of the plurality of magnetically conductive members 12 is configured to have better magnetic permeability in the radial direction of the support member 11 than in the chordal direction of the support member 11. That is, the magnetically conductive members 12 are anisotropic in terms of magnetic permeability. It should be understood that the radial direction refers to the direction intersecting the central axis O in a radial plane (i.e., a section perpendicular to the central axis O), and the chordal direction refers to the direction perpendicular to the radial direction in the radial plane. The radial direction and chordal direction of the support member 11 may also be referred to as the radial direction and chordal direction of the rotor 10, and are used interchangeably herein.

[0030] Thus, during the operation of the switched reluctance motor 100, when the magnetic conductor 12 of the rotor 10 is aligned with the stator winding 24 and the stator teeth 22 on both sides of one phase (e.g., the first phase) of the stator 20, the magnetic reluctance of that phase is minimum, and therefore the inductance of that phase of the motor is maximum. At this time, because the magnetic conductor 12 has better magnetic permeability in the radial direction, the magnetic flux generated by the stator winding 24 is more easily introduced into the magnetic conductor 12, making the minimum magnetic reluctance of that phase smaller than that of a conventional switched reluctance motor. On the other hand, when the magnetic conductor 12 of the rotor 10 is misaligned with the stator winding 24 and the stator teeth 22 on both sides of that phase of the stator 20, the magnetic reluctance of that phase is maximum, and therefore the inductance of that phase of the motor is minimum. At this time, the maximum magnetic reluctance is mainly determined by the air, and is less affected by the magnetic conductor 12. Therefore, during the operation of the switched reluctance motor 100 of this application, the slope of the reluctance change is greater, and the slope of the inductance change is also greater, which correspondingly improves the motor's torque generation capability, thereby improving motor efficiency. Furthermore, since the motor's torque generation capability is improved, the design dimensions of the motor's stator, rotor, and other related components can be reduced, ultimately translating into cost reduction.

[0031] To ensure the magnetic conductive member 12 of the rotor 10 possesses the aforementioned magnetic permeability, the magnetic conductive member 12 is preferably formed by stacking multiple grain-oriented silicon steel sheets, and the magnetic conductive member 12 is arranged such that the rolling direction of each grain-oriented silicon steel sheet is aligned with the radial direction of the support member 11. Existing switched reluctance motor rotors typically use non-oriented silicon steel sheets to facilitate the formation of magnetic circuits in all directions. However, in the switched reluctance motor of this application, the magnetic conductive member 12 is made of grain-oriented silicon steel sheets. Due to the easy magnetization axis of the grain-oriented silicon steel sheets and the rolling direction (e.g., ... Figure 3 As indicated by the arrows in the diagram, the grain-oriented silicon steel sheets are parallel to each other, and their magnetic permeability is better in the rolling direction than in the transverse direction (which is perpendicular to the rolling direction) (i.e., higher permeability). Therefore, when the grain-oriented silicon steel sheets are arranged so that their rolling direction is aligned with the radial direction of the support member 11, the aforementioned changes in reluctance and inductance can be achieved, thereby improving the torque generation capability of the motor. Furthermore, using grain-oriented silicon steel sheets not only improves motor efficiency but also reduces the amount of material used and the size of the motor, while also significantly improving the overall performance of the switched reluctance motor.

[0032] It should be noted that the magnetically conductive component 12 can also have other configurations. For example, the magnetic conductivity of the magnetically conductive component in different directions can be adjusted by providing air gaps or magnetic barrier materials in different directions in a non-oriented silicon steel sheet.

[0033] like Figure 2 As shown, the magnetically conductive outer surface 14 of the magnetically conductive member 12 can form a smooth circumferential outer surface with a portion of the supporting outer surface 17. Therefore, when the rotor 10 rotates at high speed, the rotor 10 rotates more smoothly, with less noise, and the wind resistance loss on the outer surface of the rotor 10 is significantly reduced, thereby improving motor efficiency.

[0034] In addition to the magnetically conductive outer surface 14, the magnetically conductive member 12 also has an inner surface 15 protruding toward the central axis O of the support member 11. The inner surface 15 forms the main surface that connects with the groove 18 of the support member 11. For example, the magnetically conductive member 12 can be bonded, welded, or embedded in the groove 18 via the inner surface 15, thereby forming a robust structure between the magnetically conductive member 12 and the support member 11, preventing structural damage during high-speed rotation of the rotor 10. Preferably, the inner surface 15 may have a V-shaped surface, an arc-shaped surface, or a stepped surface extending in a direction parallel to the central axis O. This not only increases the surface area of ​​contact between the magnetically conductive member 12 and the groove 18 of the support member 11 but also better guides the magnetic flux.

[0035] In addition, such as Figure 2As shown, the magnetically conductive member 12 may also have a side surface 16 located between the outer magnetically conductive surface 14 and the inner magnetically conductive surface 15, the side surface 16 extending a predetermined distance in the radial direction. The side surface 16 may also be bonded, welded, or embedded in the groove 18, thereby further enhancing the connection strength between the magnetically conductive member 12 and the support member 11. In addition, the predetermined distance the side surface 16 extends can be determined according to the strength and distribution of the magnetic field generated by the stator winding 24, etc., to facilitate the formation of a closed loop of magnetic flux.

[0036] The following reference Figure 1 This will further describe the working principle of the switched reluctance motor of this application. For example... Figure 1 As shown, in the first phase stator winding 24 (in Figure 1 The current (indicated by "A1", "A2", "A3" and "A4") is supplied (current direction as follows) Figure 1 The "⊙" and When (as shown), magnetic flux is generated around each stator winding (the direction of the magnetic flux is as shown). Figure 1 (The arrow in the diagram is shown schematically). Figure 1 In the example, the rotor salient pole defined by the magnetic guide member 12 of the rotor 10 is substantially aligned with the stator salient pole defined by the stator winding 24 of the first phase and the stator teeth 22 on both sides. Therefore, in this case, the magnetic reluctance of the first phase is minimal, and the inductance of the first phase is maximum. As the rotor 10 continues to rotate, the magnetic guide member 12 gradually rotates away from the stator winding of the first phase, and the magnetic reluctance of the first phase gradually increases until the maximum magnetic reluctance is reached, at which point the inductance of the first phase is minimal. As mentioned above, on the one hand, due to the anisotropy of the magnetic guide member 12, the minimum magnetic reluctance of the first phase is smaller than that of the same phase in a conventional switched reluctance motor, and therefore the maximum inductance of the first phase is larger than that of the same phase in a conventional switched reluctance motor. On the other hand, the maximum magnetic reluctance of the first phase is basically determined by air and is less affected by the magnetic guide member. Therefore, with regard to the first phase, the inductance change slope of the switched reluctance motor of this application is greater, thereby increasing the torque generation capability of the motor. Additionally, during the rotation of rotor 10, the second phase stator winding 24 (in) Figure 1 The stator windings 24 of the third phase (marked as "B1", "B2", "B3" and "B4") are in the middle. Figure 1 The phases (marked as "C1", "C2", "C3", and "C4") are energized or de-energized at different times (i.e., triggered in different sequences), causing the second and third phases to sequentially experience the minimum and maximum reluctance values, thereby driving the rotor 10 to rotate continuously. Furthermore, the minimum reluctance values ​​of the second and third phases are also less than the minimum reluctance values ​​of the corresponding phases in a conventional switched reluctance motor. Figure 1In the example shown, the stator winding 24 can be a flat conductor winding, and the current direction of the flat conductors in each stator slot is consistent. Furthermore, the current direction in the stator winding 24 of the first phase is not limited to... Figure 1 The direction is shown in the figure. Similarly, the stator windings of the second and third phases can also have various current directions.

[0037] According to various embodiments of this application, by specifically configuring the rotor of the switched reluctance motor, the magnetic permeability of the rotor's magnetic conductive components is better in the radial direction than in the chordal direction. This allows for a further increase in the slope of the motor's inductance change, thereby improving the motor's torque generation capability and ultimately increasing its efficiency. Furthermore, with the improvement in the motor's torque generation capability, the design dimensions of the motor's related components can be further reduced, thereby lowering the motor's cost.

[0038] The present application has been described in detail above with reference to specific embodiments. Obviously, the above description and the embodiments shown in the accompanying drawings should be understood as exemplary and not as limiting the present application. Those skilled in the art can make various modifications or alterations without departing from the spirit of the present application, and such modifications or alterations do not depart from the scope of the present application.

Claims

1. A rotor (10) for a switched reluctance motor (100), comprising: A support member (11) has a support outer surface (17) disposed around the central axis (O) of the support member (11), and a plurality of grooves (18) uniformly distributed circumferentially are formed on the support outer surface (17). The rotor (10) is characterized in that it further includes a plurality of magnetically conductive members (12), which are disposed in the groove (18), and adjacent pairs of the plurality of magnetically conductive members (12) are separated by a portion of the supporting outer surface (17). Each of the plurality of magnetically conductive components (12) is configured to have better magnetic permeability in the radial direction of the support component (11) than in the chordal direction of the support component (11), the chordal direction being perpendicular to the radial direction.

2. The rotor (10) according to claim 1, characterized in that, The magnetic conductive component (12) is formed by stacking multiple grain-oriented silicon steel sheets, and the magnetic conductive component (12) is arranged such that the rolling direction of each grain-oriented silicon steel sheet is consistent with the radial direction.

3. The rotor (10) according to claim 1 or 2, characterized in that, The magnetically conductive outer surface (14) of the magnetically conductive member (12) and a portion of the supporting outer surface (17) form a smooth circumferential outer surface.

4. The rotor (10) according to claim 3, characterized in that, The magnetically conductive member (12) also has an inner surface (15) protruding toward the central axis (O).

5. The rotor (10) according to claim 4, characterized in that, The inner surface (15) has a V-shaped surface, an arc-shaped surface or a stepped surface extending in a direction parallel to the central axis (O).

6. The rotor (10) according to claim 5, characterized in that, The magnetically conductive member (12) also has a side surface (16) located between the magnetically conductive outer surface (14) and the inner surface (15), the side surface (16) extending a predetermined distance in the radial direction.

7. The rotor (10) according to claim 1, characterized in that, The magnetic conductive component (12) is bonded, welded or embedded in the groove (18).

8. The rotor (10) according to claim 1, characterized in that, The support member (11) is non-magnetic.

9. A switched reluctance motor (100), characterized in that, The switched reluctance motor (100) includes: The rotor (10) according to any one of claims 1 to 8; and A stator (20) that houses the rotor (10) and includes: A stator core (21) having a plurality of stator teeth (22) extending toward the central axis (O) of the rotor (10), wherein adjacent stator teeth (22) form stator slots (23); and The stator winding (24) is disposed in the stator slot (23) and configured to generate a magnetic field when energized, the magnetic field acting on the magnetic conductor (12) of the rotor (10).

10. The switched reluctance motor (100) according to claim 9, characterized in that, The stator winding (24) is divided into multiple phases, and each phase contains stator windings (24) configured to be energized and de-energized at different times.

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