High-voltage switch, permanent magnet synchronous electric motor, electric motor rotor and rotor unit

Abstract

The present application relates to a high-voltage switch, a permanent magnet synchronous electric motor, an electric motor rotor and a rotor unit. Each unit portion is provided with two mounting air gaps arranged at an included angle, a first weight-reducing hole provided in a region between the two mounting air gaps and the outer side edge of the rotor unit, and a second weight-reducing hole provided in a region between the two mounting air gaps and the inner side edge of the rotor unit. At least one third weight-reducing hole is provided in the rotor unit, which is located in a region between every two adjacent unit portions. Each magnetic pole comprises two branches correspondingly arranged in the two mounting air gaps. Under the condition that the structural strength of the rotor is met, materials are reduced as much as possible by means of hole formation, the overall rotational inertia of the rotor is greatly reduced, and the power factor is improved. In addition, the first weight-reducing hole, the second weight-reducing hole and the third weight-reducing hole are respectively and uniformly distributed on the rotor unit, such that during the rotation of the electric motor rotor, a stress is uniform, and large-scale deformation cannot occur.

Description

High-voltage switch, permanent magnet synchronous motor, motor rotor and rotor unit Technical Field

[0001] The present application relates to the technical field of permanent magnet synchronous motors, and in particular to a high-voltage switch, a permanent magnet synchronous motor, a motor rotor, and a rotor unit. Background Art

[0002] With the development of motor technology, we have accumulated many years of research on new permanent magnet synchronous motor-driven high-voltage circuit breakers, including motor control system analysis, control system design and development, and small single-phase experimental prototype development. We have also completed the opening and closing performance test on the experimental prototype.

[0003] In related technologies, the time required for a high-voltage switch to open or close is typically in the millisecond range. Consequently, the servo motors that drive the high-voltage switch typically place higher demands on their performance. However, most high-power servo motors currently available on the market cannot simultaneously deliver the required high torque, low inertia, and high power density.

[0004] Summary of the Invention

[0005] Based on this, it is necessary to overcome the defects of the existing technology and provide a high-voltage switch, a permanent magnet synchronous motor, a motor rotor and a rotor unit, which can reduce the moment of inertia and ensure its own structural strength while meeting the torque requirements.

[0006] A rotor unit is provided with a plurality of unit parts evenly arranged around its circumference and a plurality of magnetic poles correspondingly arranged on each of the unit parts; each of the unit parts is arranged symmetrically about the radial axis of the rotor unit;

[0007] Each of the unit parts is provided with two mounting air gaps set at an angle, a first weight-reducing hole provided in the area between the two mounting air gaps and the outer edge of the rotor unit, and a second weight-reducing hole provided in the area between the two mounting air gaps and the inner edge of the rotor unit; at least one third weight-reducing hole is provided on the rotor unit located in the area between two adjacent unit parts; each of the magnetic poles includes two branches, and the two branches are correspondingly provided in the two mounting air gaps.

[0008] In one embodiment, the first weight-reducing holes are of the same size and are arranged at equal intervals around the circumference of the rotor unit; the first weight-reducing holes are configured as triangular holes, quadrilateral holes, pentagonal holes, circular holes, or elliptical holes;

[0009] The second weight-reducing holes are of the same size and are arranged at equal intervals around the circumference of the rotor unit; the second weight-reducing holes are configured as triangular holes, quadrilateral holes, pentagonal holes, circular holes or elliptical holes;

[0010] The third weight-reducing holes are of the same size and are arranged at equal intervals around the circumference of the rotor unit; the third weight-reducing holes are configured as triangular holes, quadrilateral holes, pentagonal holes, circular holes or elliptical holes.

[0011] In one embodiment, there are two third weight-reducing holes located in the area between two adjacent unit parts and they are arranged in sequence along the radial direction of the rotor unit; the center line connecting the two third weight-reducing holes located in the area between two adjacent unit parts is set as the first axis Z; the two unit parts located on opposite sides of the first axis Z are axially symmetrically arranged about the first axis Z; the radial line of each unit part passes through the center of the first weight-reducing hole and the center of the second weight-reducing hole respectively.

[0012] In one embodiment, the width extension directions W of the two branches of each magnetic pole are perpendicular to each other.

[0013] In one embodiment, the mounting air gap includes a mounting groove adapted to the shape of the branch, and the branch is fixedly inserted into the mounting groove; the mounting air gap also includes two magnetic isolation air gap grooves located on opposite sides of the mounting groove, and the magnetic isolation air gap grooves are connected to the mounting groove; the distance S between the two relative inner walls of the magnetic isolation air gap groove tends to decrease in the direction away from the mounting groove.

[0014] A motor rotor comprises at least one rotor unit as described above.

[0015] In one embodiment, the rotor units are provided in plurality and are coaxially connected in sequence; along the axial direction, the rotor unit ranked first is set as the first rotor unit, and the remaining rotor units are deflected relative to the first rotor unit in the same direction, and the deflection angle relative to the first rotor unit tends to increase in the direction away from the first rotor unit.

[0016] In one embodiment, the deflection angle between any two adjacent rotor units is 10° to 20°.

[0017] A permanent magnet synchronous motor comprises the motor rotor.

[0018] A high-voltage switch comprises the permanent magnet synchronous motor.

[0019] The high-voltage switchgear, permanent magnet synchronous motor, motor rotor, and rotor unit described above feature first and second lightening holes on each unit, and at least one third lightening hole on the rotor unit located between two adjacent units. While ensuring the structural strength of the rotor itself, the holes are used to minimize material reduction, significantly reducing the rotor's overall moment of inertia and improving the power factor. Furthermore, because the individual units of the rotor unit are evenly arranged and each unit is symmetrically arranged about the rotor unit's radial axis, the first, second, and third lightening holes are each relatively evenly distributed on the rotor unit. This ensures that the rotor is subjected to uniform force during rotation, preventing large-scale deformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG1 is a schematic structural diagram of a rotor unit according to an embodiment of the present application.

[0021] FIG2 is a schematic structural diagram of a unit portion in the structure shown in FIG1 .

[0022] FIG3 is a schematic structural diagram of a motor rotor according to an embodiment of the present application.

[0023] 10. Rotor unit; 11. Unit part; 111. Mounting air gap; 1111. Mounting slot; 1112. Magnetic isolation air gap slot; 112. First lightening hole; 113. Second lightening hole; 12. Magnetic pole; 121. Branch; 13. Third lightening hole; 14. First rotor unit; 15. Reference line. DETAILED DESCRIPTION

[0024] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0025] Referring to Figures 1 and 2, Figure 1 shows a schematic structural diagram of a rotor unit 10 according to one embodiment of the present application. Figure 2 shows a schematic structural diagram of a unit portion 11 in the structure shown in Figure 1. A rotor unit 10 according to one embodiment of the present application is provided, comprising a plurality of unit portions 11 evenly arranged around its circumference and a plurality of magnetic poles 12 correspondingly disposed on each unit portion 11. Each unit portion 11 is arranged symmetrically about a radius line D of the rotor unit 10. Each unit portion 11 is provided with two mounting air gaps 111 arranged at an angle, a first lightening hole 112 disposed between the two mounting air gaps 111 and the outer edge of the rotor unit 10, and a second lightening hole 113 disposed between the two mounting air gaps 111 and the inner edge of the rotor unit 10. At least one third lightening hole 13 is provided on the rotor unit 10 located between two adjacent unit portions 11. Each magnetic pole 12 includes two branches 121, with the two branches 121 correspondingly disposed in the two mounting air gaps 111.

[0026] It should be noted that the two branches 121 of each magnetic pole 12 have the same polarity, that is, for the same magnetic pole 12, as shown in Figures 1 and 2, the respective N poles and S poles of the two branches 121 are arranged in the same manner in the corresponding mounting air gap 111. Specifically, the N poles of the two branches 121 are both located on one of the axial end faces of the rotor unit 10, and the S poles are both located on the other axial end face of the rotor unit 10.

[0027] The north and south poles of any two adjacent magnetic poles 12 along the circumference of the rotor unit 10 are arranged in opposite directions. That is, as shown in FIG1 , the north pole of one magnetic pole 12 and the south pole of the other magnetic pole 12 are arranged on one axial end face of the rotor unit 10; and the south pole of one magnetic pole 12 and the north pole of the other magnetic pole 12 are arranged on the other axial end face of the rotor unit 10. In this way, any two adjacent magnetic poles 12 form a magnetic pair, providing magnetic flux for the motor's rotation.

[0028] The specific shape of each magnetic pole 12 can be flexibly adjusted and configured according to actual needs to form a cylindrical body with a rectangular, triangular, circular, elliptical, or other regular or irregular cross-section. In this embodiment, a rectangular body is used as an example, but the present invention is not limited thereto. The length of the magnetic pole 12 extends parallel to the axial direction of the rotor unit 10; the width of the magnetic pole 12 extends in the direction indicated by the double arrow W in FIG. 1 , and the thickness of the magnetic pole 12 is perpendicular to the length and width directions of the magnetic pole 12.

[0029] In some embodiments, the branch 121 includes but is not limited to being configured as a permanent magnet, magnetic steel, etc.

[0030] The aforementioned rotor unit 10, because each unit portion 11 is provided with a first lightening hole 112 and a second lightening hole 113, and at least one third lightening hole 13 is provided on the rotor unit 10 located between two adjacent unit portions 11, while ensuring the structural strength of the rotor itself, the material is reduced as much as possible through the openings, greatly reducing the overall moment of inertia of the rotor and improving the power factor. In addition, because the individual unit portions 11 of the rotor unit 10 are evenly arranged, and each unit portion 11 is symmetrically arranged about the radial axis of the rotor unit 10, the first lightening hole 112, the second lightening hole 113, and the third lightening hole 13 are each relatively evenly arranged on the rotor unit 10. As a result, during the rotation of the motor rotor, the force is evenly applied and large-scale deformation does not occur.

[0031] Please refer to Figures 1 and 2. In some embodiments, the first weight-reducing holes 112, the second weight-reducing holes 113, and the third weight-reducing holes 13 are each arranged at equal intervals around the circumference of the rotor unit 10. In this way, each first weight-reducing hole 112, each second weight-reducing hole 113, and each third weight-reducing hole 13 are evenly arranged on the rotor unit 10, and the structure is symmetrical, so that during the rotation of the motor rotor, the force is evenly applied and large-scale deformation does not occur.

[0032] Referring to Figures 1 and 2 , in some embodiments, the first lightening hole 112, the second lightening hole 113, and the third lightening hole 13 are independently provided. The specific shapes of each can be flexibly adjusted and configured according to actual needs, including but not limited to regular shapes such as polygonal holes, circular holes, and elliptical holes, as well as other irregular shapes, which are not limited here. Polygonal holes include but are not limited to triangles, quadrilaterals, pentagons, hexagons, etc.

[0033] Please refer to Figures 1 and 2. In some embodiments, when the first weight-reducing hole 112 is set as a triangular hole, especially an isosceles triangular hole, the area of ​​the hollow region can be increased as much as possible while ensuring sufficient structural strength. At the same time, it is easy to obtain through mechanical processing, thereby improving processing efficiency.

[0034] Please refer to Figures 1 and 2. In some embodiments, when the second weight-reducing hole 113 is set as a rectangular hole, a waist-shaped hole or an elliptical hole, the area of ​​the hollow region can be increased as much as possible within a limited space. At the same time, due to the regular shape, it can be easily obtained through mechanical processing, and the processing efficiency is high.

[0035] Please refer to Figures 1 and 2. In some embodiments, the number of third weight-reducing holes 13 located in the area between two adjacent unit parts 11 is not limited to one, and can be, for example, two, three, four, or other numbers. In this embodiment, the number of third weight-reducing holes 13 located in the area between two adjacent unit parts 11 is, for example, set to two, and the two third weight-reducing holes 13 have the same shape but different sizes, so as to maximize the area of ​​the hollow area while ensuring sufficient structural strength, thereby reducing the moment of inertia. Optionally, both third weight-reducing holes 13 are set to circular holes, and the area of ​​the third weight-reducing hole 13 close to the outer edge of the rotor unit 10 is smaller than the area of ​​the third weight-reducing hole 13 close to the inner edge of the rotor unit 10.

[0036] Referring to Figures 1 and 2 , in one embodiment, two third lightening holes 13 are provided between two adjacent unit sections 11 and arranged radially in sequence along the rotor unit 10. The centerline connecting the two third lightening holes 13 between the two adjacent unit sections 11 is defined as the first axis Z. The two unit sections 11 located on opposite sides of the first axis Z are arranged symmetrically about the first axis Z. This arrangement of the two third lightening holes 13 is more rational, not only reducing the moment of inertia but also ensuring structural symmetry, ensuring uniform force distribution during rotor rotation and preventing large-scale deformation.

[0037] Referring to Figures 1 and 2 , in one embodiment, the radial line of each unit portion 11 passes through the center of the first lightening hole 112 and the center of the second lightening hole 113. This creates a symmetrical structure for the unit portion 11, ensuring uniform force during rotation of the motor rotor and preventing large-scale deformation.

[0038] 1 and 2 , in one embodiment, the second lightening holes 113 and the third lightening holes 13 close to the inner edge of the rotor unit 10 are alternately arranged in sequence along the circumferential direction of the rotor unit 10 .

[0039] 1 and 2 , in some embodiments, for each magnetic pole 12 , the width extension directions W of the two branches 121 thereof are arranged at an angle, including but not limited to 15° to 165°, specifically 60° to 120°.

[0040] Referring to Figures 1 and 2 , in one embodiment, the width extension directions W of the two branches 121 of each magnetic pole 12 are perpendicular to each other. Thus, when the two branches 121 of the magnetic pole 12 are arranged vertically, the distribution of magnetic flux lines is more uniform, thereby improving the rotational stability of the motor rotor.

[0041] Referring to Figures 1 and 2 , in one embodiment, mounting gap 111 includes a mounting groove 1111 adapted to the shape of branch 121, with branch 121 securely inserted within mounting groove 1111. Thus, the inner contour of mounting groove 1111 matches the outer contour of branch 121, improving mounting stability and preventing misalignment and deformation of magnetic pole 12 during high-speed motor operation.

[0042] Specifically, the cross section of the mounting groove 1111 is set to be rectangular, and the two sides of the rectangle are respectively the same as the width and thickness of the branch 121, so that the inner wall contour of the mounting groove 1111 and the outer contour of the branch 121 are consistent with each other.

[0043] Please refer to Figures 1 and 2. In one embodiment, the mounting air gap 111 also includes two magnetic isolation air gap slots 1112 located on opposite sides of the mounting slot 1111. The magnetic isolation air gap slots 1112 are connected to the mounting slot 1111. The spacing S between the two inner walls of the magnetic isolation air gap slot 1112 decreases in the direction away from the mounting slot 1111. In this way, on the one hand, it can limit the leakage flux when the magnetic flux reaches saturation; on the other hand, it can reduce the moment of inertia. In addition, since the spacing S between the two inner walls of the magnetic isolation air gap slot 1112 decreases in the direction away from the mounting slot 1111, it also limits the branch 121, thereby improving the installation stability of the branch 121 in the mounting slot 1111 and preventing the magnetic pole 12 from being dislocated and deformed when the motor moves at high speed.

[0044] Referring to FIG. 1 and FIG. 2 , in some embodiments, the axial cross-sectional shape of the magnetic isolation air gap slot 1112 includes but is not limited to a regular shape such as a triangle or other irregular shapes.

[0045] In one embodiment, the rotor unit 10 includes a plurality of laminated sheets.

[0046] Please refer to FIG. 1 and FIG. 3 . In one embodiment, a motor rotor includes at least one rotor unit 10 according to any one of the above embodiments.

[0047] The motor rotor described above has a first lightening hole 112 and a second lightening hole 113 on each unit 11, and at least one third lightening hole 13 is provided on the rotor unit 10 located between two adjacent units 11. While ensuring the structural strength of the rotor itself, the material is reduced as much as possible through the openings, significantly reducing the rotor's overall moment of inertia and improving the power factor. Furthermore, because the individual units 11 of the rotor unit 10 are evenly arranged, and each unit 11 is symmetrically arranged about the radial axis of the rotor unit 10, the first lightening hole 112, the second lightening hole 113, and the third lightening hole 13 are each relatively evenly arranged on the rotor unit 10. This allows the rotor to be subjected to uniform force during rotation, preventing large-scale deformation.

[0048] The motor in this embodiment is specifically a high-power permanent magnet synchronous motor with a large number of rotor poles and stator slots, which easily generates cogging torque. Cogging torque is the torque generated by the interaction between the permanent magnets and the stator core when the permanent magnet synchronous motor's windings are deenergized. It is caused by the pulsation of the tangential component of the interaction force between the permanent magnets and the stator teeth. When the motor rotor rotates, the magnetic permeance within a small area on both sides of the permanent magnet corresponding to the stator slots changes significantly, causing changes in the magnetic field energy storage, thereby generating cogging torque.

[0049] Please refer to Figures 1 and 3. Figure 3 shows a schematic structural diagram of a motor rotor according to one embodiment of the present application. In one embodiment, a plurality of rotor units 10 are provided and coaxially connected in sequence. In the axial direction, the rotor unit 10 ranked first is designated as the first rotor unit 14, and the remaining rotor units 10 are all deflected in the same direction relative to the first rotor unit 14. Specifically, as shown in Figure 3, the reference line 15 on each rotor unit 10 is deflected by a certain angle relative to the reference line 15 on the first rotor unit 14, for example, in a clockwise direction. Furthermore, the deflection angle relative to the first rotor unit 14 tends to increase in a direction away from the first rotor unit 14. This structural form can improve the efficiency of the motor, bringing the rotor magnetic flux lines closer to the stator magnetic flux lines and reducing magnetic flux leakage. This results in a higher starting torque, better operating stability, and lower noise for the motor.

[0050] 1 and 3 , in one embodiment, the deflection angle between any two adjacent rotor units 10 is 10° to 20°. Specifically, the deflection angle between any two adjacent rotor units 10 is independently set, including but not limited to various angle values ​​such as 10°, 13°, 15°, 18°, and 20°.

[0051] In a specific embodiment, when the deflection angles of any two adjacent rotor units 10 are set to 15°, for example, through simulation calculations and actual manufacturing comparisons, it is found that this is the most suitable angle value for high-voltage switch motors. This can greatly weaken the motor's own cogging torque, reduce vibration and noise, reduce speed fluctuations, enable the motor to run smoothly, and improve the motor's performance parameters.

[0052] Please refer to FIG. 1 and FIG. 2 . In one embodiment, a permanent magnet synchronous motor is provided. The permanent magnet synchronous motor includes the motor rotor of any one of the above embodiments.

[0053] In the permanent magnet synchronous motor described above, since each unit portion 11 is provided with a first lightening hole 112 and a second lightening hole 113, and at least one third lightening hole 13 is provided on the rotor unit 10 located in the area between two adjacent unit portions 11, while ensuring the structural strength of the rotor itself, the material is reduced as much as possible by opening holes, greatly reducing the overall moment of inertia of the rotor and improving the power factor. In addition, since the individual unit portions 11 of the rotor unit 10 are evenly arranged, and each unit portion 11 is symmetrically arranged about the radial axis of the rotor unit 10, the first lightening hole 112, the second lightening hole 113, and the third lightening hole 13 are each relatively evenly arranged on the rotor unit 10. In this way, during the rotation of the motor rotor, the force is evenly applied and large-scale deformation does not occur.

[0054] Please refer to FIG. 1 and FIG. 2 . In one embodiment, a high-voltage switch is provided. The high-voltage switch includes the permanent magnet synchronous motor according to any one of the above embodiments.

[0055] The high-voltage switch described above features a first lightening hole 112 and a second lightening hole 113 on each unit 11, and at least one third lightening hole 13 on the rotor unit 10 located between two adjacent units 11. While ensuring the structural strength of the rotor itself, the openings are used to minimize material reduction, significantly reducing the rotor's overall moment of inertia and improving the power factor. Furthermore, because the individual units 11 of the rotor unit 10 are evenly arranged, and each unit 11 is symmetrically arranged about the radial axis of the rotor unit 10, the first, second, and third lightening holes 112, 113, and 13 are each relatively evenly distributed on the rotor unit 10. This ensures that the rotor is subjected to uniform force during rotation, preventing large-scale deformation.

[0056] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0057] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0058] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0059] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0060] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0061] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0062] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A rotor unit, characterized in that: The rotor unit is provided with a plurality of unit parts evenly arranged around its circumferential direction and a plurality of magnetic poles correspondingly arranged on each of the unit parts; each of the unit parts is arranged symmetrically about the radial axis of the rotor unit; Each of the unit parts is provided with two installation air gaps set at an angle, a first weight-reducing hole provided in the area between the two installation air gaps and the outer edge of the rotor unit, and a second weight-reducing hole provided in the area between the two installation air gaps and the inner edge of the rotor unit; at least one third weight-reducing hole is provided on the rotor unit located in the area between two adjacent unit parts; each of the magnetic poles includes two branches, and the two branches are correspondingly arranged in the two installation air gaps.

2. The rotor unit according to claim 1, characterized in that: The first weight-reducing holes are of the same size and are arranged at equal intervals around the circumference of the rotor unit; the first weight-reducing holes are set to be triangular holes, quadrilateral holes, pentagonal holes, circular holes or elliptical holes; The second weight-reducing holes are of the same size and are arranged at equal intervals around the circumference of the rotor unit; the second weight-reducing holes are set to be triangular holes, quadrilateral holes, pentagonal holes, circular holes or elliptical holes; The third weight-reducing holes are of the same size and are arranged at equal intervals around the circumferential direction of the rotor unit; the third weight-reducing holes are configured to be triangular holes, quadrilateral holes, pentagonal holes, circular holes or elliptical holes.

3. The rotor unit according to claim 2, characterized in that: The number of the third weight-reducing holes located in the area between two adjacent unit parts is set to two and they are arranged sequentially along the radial direction of the rotor unit; the center line connecting the two third weight-reducing holes located in the area between two adjacent unit parts is set to the first axis Z; the two unit parts located on opposite sides of the first axis Z are axially symmetrically arranged about the first axis Z; the radial line of each unit part passes through the center of the first weight-reducing hole and the center of the second weight-reducing hole respectively.

4. The rotor unit according to claim 1, characterized in that: The width extension directions W of the two branches of each magnetic pole are arranged perpendicular to each other.

5. The rotor unit according to claim 1, characterized in that: The mounting air gap includes a mounting groove adapted to the shape of the branch, and the branch is fixedly inserted in the mounting groove; the mounting air gap also includes two magnetic isolation air gap grooves located on opposite sides of the mounting groove, and the magnetic isolation air gap grooves are connected to the mounting groove; the spacing S between the two relative inner walls of the magnetic isolation air gap groove tends to decrease in the direction away from the mounting groove.

6. A motor rotor, characterized in that: The motor rotor comprises at least one rotor unit according to any one of claims 1 to 5.

7. The motor rotor according to claim 6, characterized in that: The rotor units are provided in plurality and are coaxially connected in sequence; along the axial direction, the rotor unit ranked first is set as the first rotor unit, and the remaining rotor units are all deflected relative to the first rotor unit in the same direction, and the deflection angle relative to the first rotor unit tends to increase in the direction away from the first rotor unit.

8. The motor rotor according to claim 7, characterized in that: The deflection angle between any two adjacent rotor units is 10° to 20°.

9. A permanent magnet synchronous motor, characterized in that: The permanent magnet synchronous motor comprises the motor rotor as claimed in any one of claims 6 to 8.

10. A high voltage switch, characterized in that: The high voltage switch comprises the permanent magnet synchronous motor as claimed in claim 9.

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