A magnetic flux switching motor and a high voltage circuit breaker

Abstract

The application discloses a flux switching motor and a high-voltage circuit breaker. The flux switching motor comprises a rotor core, a bearing and a stator assembly. The stator assembly is internally provided with a mounting cavity. The bearing is arranged at the center of the mounting cavity. The rotor core is sleeved on the bearing. An air gap is formed between the stator assembly and the rotor core. The rotor core comprises a rotor tooth part and a rotor yoke part which are integrated. The rotor yoke part is sleeved on the bearing. The rotor tooth part is arranged at the outer periphery of the rotor yoke part and is provided with a plurality of tooth parts. The extension length of the rotor tooth part in the radial direction of the rotor core is greater than or equal to the extension length of the rotor yoke part in the radial direction of the rotor core. The high-voltage circuit breaker comprises the flux switching motor. The application relates to the technical field of motors and provides the flux switching motor and the high-voltage circuit breaker. The length of the rotor tooth part is increased to improve the torque and rotational inertia ratio of the motor, so that the dynamic response capability of the motor is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric machines, and more particularly, to a flux switching electric machine for a high-voltage circuit breaker. BACKGROUND

[0002] At present, new energy vehicles, smart grids and other technologies are being developed and applied. The smart grid requires monitoring the electrical state and control state of high-voltage switching equipment, which has higher requirements for the controllability of switching equipment. Since the controllability of the operating mechanism does not meet the standards, the core control function of the existing high-voltage circuit breaker has not yet reached the level of intelligence. The traditional high-voltage circuit breaker operating mechanism mainly includes electromagnetic operating mechanisms, spring operating mechanisms, pneumatic operating mechanisms, and hydraulic operating mechanisms. These operating mechanisms have poor flexibility, large dispersion of action time, are not conducive to production and maintenance, and have extremely poor reliability. Due to the advantages of reliability, online flexible control capability, simple structure, and various operation and maintenance methods, electric motors will become a new type of operating mechanism for high-voltage circuit breakers. As a new type of operating mechanism for high-voltage circuit breakers, in-depth research on electric motors is beneficial to improving the breaking and closing capabilities of circuit breakers, improving the mechanical and electrical life and operation reliability, and improving the intelligent level of smart grid equipment, breaking through foreign technical barriers, and thus achieving huge economic benefits and social benefits.

[0003] The electric motor drive high-voltage circuit breaker systems developed at home and abroad generally use general-purpose motors as driving mechanisms. However, the driving motor needs to consider heat dissipation and other issues under high-power conditions. Moreover, the motor applied to the working conditions of high-voltage circuit breakers needs to have high current overload, extremely short running time, and other conditions. Therefore, the general-purpose motor is not reasonable in terms of technology and economy. In particular, the existing related general-purpose motors are also difficult to meet the requirements of high output torque, high dynamic response, high current overload, and low rotor inertia under the working conditions of high-voltage circuit breakers. SUMMARY

[0004] The embodiment of the present application provides a flux switching electric machine applied to a high-voltage circuit breaker. The flux switching electric machine comprises a rotor core, a bearing and a stator assembly. The stator assembly is provided with a mounting cavity. The bearing is arranged at the center of the mounting cavity. The bearing is sleeved with the rotor core. An air gap is formed between the stator assembly and the rotor core. The rotor core comprises a rotor tooth part and a rotor yoke part which are integrated. The rotor yoke part is sleeved on the bearing. The rotor tooth part is arranged at the outer periphery of the rotor yoke part and is provided with a plurality of rotor teeth.

[0005] The extension length of the rotor tooth part in the radial direction of the rotor core is greater than or equal to the extension length of the rotor yoke part in the radial direction of the rotor core.

[0006] In a possible design, the extension length of the rotor tooth part in the radial direction of the rotor core is Lrt The rotor yoke part extends radially from the rotor core by a length L ry wherein,

[0007] In one possible design, the stator assembly comprises a plurality of stator cores and a plurality of stator permanent magnets, the plurality of stator cores are arranged around the circumference of the stator assembly, and one stator permanent magnet is arranged between every two adjacent stator cores.

[0008] In one possible design, the stator permanent magnet comprises a rare earth permanent magnet and a ferrite permanent magnet, the rare earth permanent magnet and the ferrite permanent magnet are arranged along the radial direction of the stator assembly, the rare earth permanent magnet is arranged close to the rotor core, and the ferrite permanent magnet is arranged away from the rotor core.

[0009] In one possible design, the length of the ferrite permanent magnet in the radial direction of the stator assembly is greater than or equal to the length of the rare earth permanent magnet in the radial direction of the stator assembly.

[0010] In one possible design, the stator core comprises a plurality of silicon steel sheets stacked along the axial direction of the stator core, the stator core is arranged in a U shape and is formed by modular processing, and the stator core surrounds a stator slot.

[0011] In one possible design, the stator assembly further comprises a winding, two adjacent stator cores and the stator permanent magnet sandwiched therebetween surround a stator tooth, and the winding is arranged in the stator slot and wound on the stator tooth.

[0012] In one possible design, the number of rotor tooth parts is 5N, and the number of stator cores is 6N, where N is a positive integer.

[0013] The embodiment of the present application provides a high-voltage circuit breaker, comprising the above-mentioned flux switching motor.

[0014] The flux switching motor of the embodiment of the present application increases the length of the rotor tooth part to improve the ratio of the torque to the rotational inertia of the motor, so as to improve the dynamic response capability of the motor, and meet the requirements of high output torque, high dynamic response, high current overload and low rotor inertia under the working condition of the high-voltage circuit breaker.

[0015] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be achieved and obtained by means of the structures particularly pointed out in the description and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings are used to provide further understanding of the technical solutions of the present application, and constitute a part of the specification, and are used to explain the technical solutions of the present application together with the embodiments of the present application, and do not constitute a limitation on the technical solutions of the present application.

[0017] Figure 1 A schematic diagram of a flux switching motor according to an embodiment of the present application;

[0018] Figure 2 A schematic diagram of a flux switching motor in cross-section; Figure 1

[0019] Figure 3 A schematic diagram of a rotor core; Figure 1

[0020] Figure 4 A cross-sectional view of a rotor core; Figure 3

[0021] A first schematic diagram of a stator core and stator permanent magnet assembly; Figure 5 Figure 2 A first schematic diagram of a stator core and stator permanent magnet assembly;

[0022] Figure 6 Figure 5 A schematic diagram of a winding;

[0023] Figure 7 A schematic diagram of a winding; Figure 2

[0024] A graph of the moment of inertia of the motor versus the outer diameter of the rotor. Figure 8 The accompanying drawings are used to provide further understanding of the technical solutions of the present application, and constitute a part of the specification, and are used to explain the technical solutions of the present application together with the embodiments of the present application, and do not constitute a limitation on the technical solutions of the present application.

[0025] Specific embodiments

[0026] In order to make the objectives, technical solutions, and advantages of the present application clearer, the embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other as long as there is no conflict.

[0027] At present, the general motor is generally used as a driving mechanism for the related high-voltage circuit breaker, but the heat dissipation and other problems need to be considered for the driving motor under the condition of high power. The existing general motor is difficult to meet the requirements of high output torque, high dynamic response, high current overload, and low rotor inertia under the working condition of the high-voltage circuit breaker.

[0028] ​​​​​Please refer to Figures 1 to 7 The flux switching motor of an embodiment of the present application is applied to a high-voltage circuit breaker. The flux switching motor comprises a rotor core 2, a bearing 3 and a stator assembly 1. The stator assembly 1 is provided with a mounting cavity 7. The bearing 3 is mounted at the center of the mounting cavity 7. The bearing 3 is sleeved with the rotor core 2, so that an air gap 8 is formed between the stator assembly 1 and the rotor core 2. The rotor core 2 comprises a rotor tooth portion 10 and a rotor yoke portion 9 which are integrated. The rotor yoke portion 9 is sleeved on the bearing 3. The rotor tooth portion 10 is arranged at the outer periphery of the rotor yoke portion 9 and is provided with a plurality of rotor tooth portions 10. In addition, different from the existing rotor core, the rotor tooth portion 10 has a radial extension length of the rotor core 2 which is greater than or equal to the radial extension length of the rotor yoke portion 9 of the rotor core 2. Thus, the flux switching motor increases the length of the rotor tooth portion 10 to improve the ratio of the torque to the moment of inertia of the motor, so as to improve the dynamic response capability of the motor.

[0029] At present, the existing rotor core 2 is in a cylindrical shape. The rotor core 2 has a long rotor tooth portion 10. The rotor core 2 can be formed by axial lamination of silicon steel punching. As shown in Figures 1 to 4 , the rotor core 2 comprises a cylindrical rotor yoke portion 9 and a long strip-shaped rotor tooth portion 10. The rotor tooth portion 10 is located at the outer wall of the rotor yoke portion 9 and extends in the radial direction of the rotor core 2. The center of the rotor yoke portion 9 is provided with a through mounting hole 13. The bearing 3 is mounted in the mounting hole 13, so that the rotor core 2 can rotate in the mounting cavity 7. The rotor tooth portion 10 is provided with a plurality of rotor tooth portions 10 which are uniformly arranged around the axial direction of the rotor yoke portion 9. In the example, the rotor tooth portion 10 has 5, but is not limited to 5, for example, 10, 15 or 5 times of the multiple, that is, the number of rotor tooth portions 10 is 5×N, and N is a positive integer. The end face of each rotor tooth portion 10 away from the rotor yoke portion 9 is an arc surface which is centered on the axis of the rotor core 2. Thus, as shown in Figure 4 , the inner radius of the rotor core 2 is R ri , which is also the inner radius of the rotor yoke portion 9 and is equal to the radius of the mounting hole 13; the outer radius of the rotor core 2 is R ri ; the outer radius of the rotor yoke portion 9 is R rm ; the outer radius of the rotor core 2 is R ro ; and the tooth width of the rotor core 2 is w rt . The extension length of the rotor tooth portion 10 in the radial direction of the rotor core 2, that is, the distance from the outer surface of the rotor yoke portion 9 to the outer surface of the rotor tooth portion 10, can be referred to as the tooth length of the rotor core 2, that is, L rt . The extension length of the rotor yoke portion 9 in the radial direction of the rotor core 2, that is, the distance from the outer surface of the rotor yoke portion 9 to the inner surface of the rotor yoke portion 9, is L ry .

[0030] In some example embodiments, the ratio of the extension length of the rotor tooth 10 in the radial direction of the rotor core 2 to the extension length of the rotor yoke 9 in the radial direction of the rotor core 2 is 3, i.e. But not limited to this, the ratio is preferably 2 to 4, i.e.

[0031] For example Figure 1 、 Figure 2 、 Figures 5 to 7 As shown, the stator assembly 1 includes a plurality of stator cores 4 and a plurality of stator permanent magnets 5, and a plurality of groups of windings 6, wherein the plurality of stator cores 4 are arranged around the circumference of the stator assembly 1, and a stator permanent magnet 5 is arranged between every two adjacent stator cores 4, and the two adjacent stator cores 4 and the stator permanent magnet 5 sandwiched therebetween form a stator tooth 14, and the winding 6 is wound on the stator tooth 14. In this example, the number of stator cores 4 is 6, but it is not limited to 6, for example, it can be 12, 18, etc. 6 times, i.e. the number of stator cores 4 is 6xN, N is a positive integer, and the number of stator permanent magnets 5 is consistent with the number of stator cores 4. Among them, the stator core 4 includes a plurality of silicon steel sheets stacked in the axial direction of the stator assembly 1, and the stator core 4 is U-shaped and is modularly processed and formed, so that the stator core 4 itself forms a stator slot 15. Thus, the two adjacent stator cores 4 and the stator permanent magnet 5 therebetween form a stator tooth 14, and other adjacent stator cores 4 and stator permanent magnets 5 also form the same structure, so that the inside of the stator assembly 1 forms a plurality of stator teeth 14, and adjacent stator teeth 14 are spaced apart by stator slots 14, and a group of windings 6 is wound on a stator tooth 14, and each stator tooth 14 is provided with a winding 6, and the stator slot 14 also provides installation space for the winding 6.

[0032] As for the stator permanent magnet 5, as shown in Figure 2 、 Figures 5 to 7 , the stator permanent magnet 5 includes a rare earth permanent magnet 12 and a ferrite permanent magnet 11, wherein the rare earth permanent magnet 12 and the ferrite permanent magnet 11 are arranged in the radial direction of the stator assembly 1 (the radial direction of the stator assembly 1 is consistent with the radial direction of the rotor core 2), the rare earth permanent magnet 12 is located on the side close to the rotor core 2, and the ferrite permanent magnet 11 is located on the side away from the rotor core 2. Thus, the rare earth permanent magnet 12 and the ferrite permanent magnet 11 are combined to perform hybrid excitation, replacing the existing scheme of only rare earth permanent magnet excitation, which can reduce the amount of rare earth permanent magnet while ensuring torque density, and improve the environmental protection and economy of the machine. At the same time, the rare earth permanent magnet 12 has high residual magnetism, thereby ensuring the magnetic flux density of the air gap 8, and the ferrite permanent magnet 11 can reduce the leakage of the rare earth permanent magnet 12 at the outer diameter of the stator assembly. In addition, the length of the ferrite permanent magnet 11 in the radial direction of the stator assembly 2 is greater than the length of the rare earth permanent magnet 12 in the radial direction of the stator assembly 2, further reducing the amount of rare earth permanent magnet 12.

[0033] As can be seen from the above, there is a certain air gap 8 between the stator assembly 1 and the rotor core 2. The winding 6 generates a rotating magnetic field in the air gap 8. The stator permanent magnet 5 and the rotating rotor core 2 also form a rotating magnetic field in the air gap 8. The interaction between the winding magnetic field and the permanent magnet magnetic field generates a stable torque.

[0034] Compared with existing related motors, the rotor core 2 of existing related motors is a cylindrical or short-tooth structure. If it is a cylindrical structure, that is, only the rotor yoke 9, the formula for calculating its moment of inertia is as follows:

[0035]

[0036] The formula for calculating the moment of inertia in this example is as follows:

[0037]

[0038] Where L is the axial length of the rotor core, ρ is the density of the rotor core, and R... ri R is the inner radius of the rotor core. ri R is the outer radius of the rotor core. rm R is the outer radius of the rotor yoke. ro w is the outer radius of the rotor core. rt This represents the tooth width of the rotor core.

[0039] Comparing the two calculation formulas above, the moment of inertia of a conventional cylindrical rotor core is related to the fourth power of the rotor core's outer diameter. Therefore, as the outer diameter increases, the motor's moment of inertia increases rapidly, which is detrimental to improving dynamic response performance. However, in this example, with a fixed rotor tooth width and rotor yoke size, the slope of the rotor core's moment of inertia changing with the outer diameter is very small. Therefore, it is possible to increase torque and power without additionally increasing the moment of inertia, thereby improving the torque-to-moment-inertia ratio. Figure 8 As shown in the figure, the dashed line represents the moment of inertia curve of a typical cylindrical rotor core, while the solid line represents the moment of inertia curve of the rotor core in this example. The horizontal axis represents the outer diameter of the rotor core, and the vertical axis represents the moment of inertia. It can be seen that, with the same outer diameter of the rotor core, the moment of inertia and its growth rate of the flux-switching motor in this example are much smaller than those of a typical cylindrical rotor core. This example of a flux-switching motor improves the torque-to-moment of inertia ratio and enhances the motor's dynamic response by increasing the tooth length of the rotor core, i.e., increasing the outer diameter of the rotor. Furthermore, through experiments and calculations, the flux-switching motor in this example can achieve a moment of inertia of 0.0362 kg·m. 2 At the same time, it maintains a consistently high output torque of 15 kN·m, and the ratio of torque to moment of inertia has been greatly improved, resulting in a significant improvement in dynamic response performance.

[0040] In some example embodiments, a high-voltage circuit breaker includes the flux switching motor described above.

[0041] In combination with the above embodiments, the flux switching motor of the embodiments of the present application increases the ratio of torque to moment of inertia of the motor by increasing the length of the rotor tooth portion, thereby achieving the purpose of improving the dynamic response capability of the motor, and meeting the requirements of high output torque, high dynamic response, high current overload, and low rotor inertia under the working conditions of the high-voltage circuit breaker.

[0042] In the description in the present application, it should be noted that the terms "upper", "lower", "one side", "the other side", "one end", "the other end", "edge", "opposite", "four corners", "periphery", "mouth structure" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the structure referred to has a particular orientation, is constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0043] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the terms "connection", "direct connection", "indirect connection", "fixed connection", "installation", "assembly" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; the terms "installation", "connection", "fixed connection" can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0044] Although the embodiments disclosed by the present application are as described above, the content described is only the embodiments adopted for the convenience of understanding the present application, and is not intended to limit the present application. Any person skilled in the art of the present application can make any modification and change in the form and details without departing from the spirit and scope of the present application disclosed, but the patent protection scope of the present application shall be subject to the appended claims.

Claims

1. A flux-switching motor, applied in a high-voltage circuit breaker, the flux-switching motor comprising a rotor core, bearings, and a stator assembly, wherein the stator assembly has a mounting cavity, the bearing is disposed at the center of the mounting cavity, the rotor core is sleeved on the bearing, and an air gap is formed between the stator assembly and the rotor core, characterized in that... The rotor core includes a rotor tooth portion and a rotor yoke portion that are integral parts. The rotor yoke portion is sleeved on the bearing. The rotor tooth portion is located on the outer periphery of the rotor yoke portion and has multiple teeth. The radial extension length of the rotor teeth in the rotor core is set to be greater than the radial extension length of the rotor yoke in the rotor core. The radial extension length of the rotor teeth in the rotor core is set to Lrt, and the radial extension length of the rotor yoke in the rotor core is set to Lry, where 2 ≤ ≤4; The stator assembly includes multiple stator cores and multiple stator permanent magnets, the stator permanent magnets including rare earth permanent magnets and ferrite permanent magnets.

2. The flux-switching motor according to claim 1, characterized in that, Multiple stator cores are arranged circumferentially around the stator assembly, and a stator permanent magnet is provided between every two adjacent stator cores.

3. The flux-switching motor according to claim 2, characterized in that, The rare earth permanent magnet and the ferrite permanent magnet are arranged radially along the stator assembly, with the rare earth permanent magnet positioned close to the rotor core and the ferrite permanent magnet positioned away from the rotor core.

4. The flux-switching motor according to claim 3, characterized in that, The length of the ferrite permanent magnet in the radial direction of the stator assembly is greater than or equal to the length of the rare earth permanent magnet in the radial direction of the stator assembly.

5. The flux-switching motor according to claim 2, characterized in that, The stator core comprises multiple silicon steel sheets stacked along its axial direction. The stator core is U-shaped and modularly formed, and the stator core forms a stator slot.

6. The flux-switching motor according to claim 5, characterized in that, The stator assembly also includes a winding, and two adjacent stator cores and the stator permanent magnet sandwiched in the middle form a stator tooth. The winding is disposed in the stator slot and wound around the stator tooth.

7. The flux-switching motor according to any one of claims 2-6, characterized in that, The number of rotor teeth is set to 5×N, and the number of stator cores is set to 6×N, where N is a positive integer.

8. A high-voltage circuit breaker, characterized in that, Including the flux-switching motor as described in any one of claims 1-7.

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