A pole structure that eliminates pole coil side forces

Abstract

The present application relates to the technical field of salient pole hydroelectric generating equipment, in particular to a magnetic pole structure for eliminating lateral force of magnetic pole coil, comprising a magnetic pole coil, a magnetic pole shoe and a magnetic pole body; when the unit is static, the center line of the magnetic pole coil is perpendicular to the magnetic pole shoe and parallel to the magnetic pole body; the intersection of the extension line of the center line of the magnetic pole coil and the center line of the magnetic pole is located on the outer diameter side of the rotor center; when the unit reaches the rated speed, the center line of the magnetic pole coil is perpendicular to the magnetic pole shoe and has an angle delta with the magnetic pole body; the intersection of the extension line of the center line of the magnetic pole coil and the center line of the magnetic pole is located on the rotor center. Through the magnetic pole structure, the problem of lateral force of the magnetic pole coil can be solved.

Description

Technical Field

[0001] This invention relates to the field of salient-pole hydroelectric power generation equipment technology, and in particular to a magnetic pole structure for eliminating the lateral component force of the magnetic pole coil. Background Technology

[0002] Magnetic poles are an important component of the rotating parts of an electric motor, used to generate magnetic fields for electromechanical energy conversion. During motor operation, the magnetic poles rotate with the rotor, experiencing significant centrifugal force; therefore, they must be reliably fixed to the yoke. The magnetic pole itself consists of a pole core, a pole coil, and a fixing component for the pole coil. The pole core is typically made of thin pole laminations stacked together and held together by a pole tensioning screw. Its outer diameter side forms the pole shoe, while its inner diameter side forms the pole body with a T-tail. The T-tail of the pole fits into the T-tail groove of the yoke, securing it together. The pole coil is fitted onto the pole core, its outer side fitting snugly against the pole shoe. The centrifugal force generated by the rotation of the pole coil with the rotor is borne by the pole shoe.

[0003] When a magnetic pole coil is mounted on a magnetic pole core, and its two sides form an angle with the center of the magnetic pole, the magnetic pole coil will be subjected to a lateral force, which is the root cause of the lateral deformation of the magnetic pole coil. If the unit design adopts a tower-type magnetic pole structure, that is, the magnetic pole coil is designed with its sides arranged centripetally, theoretically the lateral force of the magnetic pole should be zero. However, in actual production, it has been found that the magnetic pole coil still exhibits significant lateral deformation. After relevant theoretical analysis and experimental research, it was found that this is because the magnetic pole shoe tilts under the force of the magnetic pole coil, causing the magnetic pole coil to no longer be centripetally arranged, thus generating a lateral force and causing the magnetic pole coil to deform laterally.

[0004] Currently, for high-speed units, especially pumped storage units, preventing excessive deformation of the magnetic pole coils and addressing the resulting safety hazards is a primary issue that needs to be resolved. Common solutions include adding inter-pole supports between adjacent magnetic pole coils or adding a surrounding band around the magnetic pole coils.

[0005] For example, in the prior art, there is a Chinese utility model patent document with publication number CN213072245U and authorization announcement date of April 27, 2021. The technical solution disclosed in this patent document is as follows: a fixing structure for the magnetic pole of a salient pole generator of a hydro turbine generator, wherein the magnetic pole core is connected to the hub and shaft of the hub by a magnetic yoke and a bracket, the magnetic pole coil is fitted on the side of the magnetic pole core, and the side and bottom of the magnetic pole coil are fixed by a shroud. The shroud is connected to the magnetic pole core by a plug-in structure and bolts. A lateral insulating pad and a bottom insulating pad are also provided between the magnetic pole coil and the shroud. An elastic buffer is provided between the insulating pad at the bottom of the magnetic pole coil and the inner wall of the shroud. The elastic buffer includes a disc spring with a disc spring cap and an adjusting shim. The elastic direction of the disc spring corresponds to the expansion direction of the magnetic pole coil under the action of excitation current.

[0006] The purpose of the above technical solutions is to reduce the deformation of the magnetic pole coil. However, the added pole support blocks or the magnetic pole coil shroud themselves will bear the force caused by the deformation of the magnetic pole coil, often causing safety hazards. At the same time, it complicates the structure and manufacturing process of the magnetic pole, affects the heat dissipation of the magnetic pole itself, and makes later maintenance of the magnetic pole extremely inconvenient. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes a magnetic pole structure that eliminates the lateral force component of the magnetic pole coil. This solves the problem of the lateral force component in the magnetic pole coil, thereby simplifying the magnetic pole coil fixing structure and eliminating the need for inter-pole supports or magnetic pole shrouds, thus improving the safety of high-speed magnetic poles. The elimination of inter-pole supports or magnetic pole shrouds will also greatly improve heat dissipation on the surface of the magnetic pole coil, simplifying subsequent magnetic pole maintenance.

[0008] This invention is achieved by adopting the following technical solution:

[0009] A magnetic pole structure for eliminating the lateral force component of a magnetic pole coil includes a magnetic pole coil, a magnetic pole shoe, and a magnetic pole body; characterized in that: when the unit is static, the center line of the magnetic pole coil is perpendicular to the magnetic pole shoe and parallel to the magnetic pole body; the intersection of the extension line of the magnetic pole coil center line and the magnetic pole center line is located on the outer diameter side of the rotor center; when the unit reaches the rated speed, the center line of the magnetic pole coil is perpendicular to the magnetic pole shoe and has an angle δ with the magnetic pole body; the intersection of the extension line of the magnetic pole coil center line and the magnetic pole center line is exactly located at the rotor center.

[0010] The magnetic pole shoe rotates around the junction of the magnetic pole shoe and the magnetic pole body under the centrifugal force of itself and the magnetic pole coil. When the unit reaches the rated speed, the rotation angle α of the magnetic pole shoe is the same as the included angle δ.

[0011] The included angle δ is calculated as follows:

[0012] δ=GL 2 / 2EI

[0013] Where G is the sum of the side weight of the magnetic pole coil and the weight of the cantilever of the magnetic pole shoe, L is the vertical distance from the center of gravity of the magnetic pole coil to the magnetic pole body, E is the elastic modulus of the magnetic pole shoe material, and I is the moment of inertia of the cross section of the cantilever segment of the pole shoe.

[0014] The calculation of the included angle δ also includes correcting the elastic modulus E of the magnetic pole shoe material. The corrected elastic modulus E ranges from 1.8 to 2.0e5 MPa.

[0015] An insulating plate separates the top surface of the magnetic pole coil from the magnetic pole shoe.

[0016] The side of the magnetic pole coil maintains an electrical distance from the magnetic pole body.

[0017] An insulating plate is provided between the side of the magnetic pole coil and the magnetic pole body, and the insulating plate is covered with felt.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. In this invention, during the initial analysis, the magnetic pole coil will have a lateral component force pointing towards the center of the magnetic pole. However, as the rotor speed increases, the magnetic pole shoe will rotate under the radial centrifugal force of the magnetic pole coil, and the magnetic pole coil will also rotate accordingly. The intersection of the extension line of the magnetic pole coil centerline and the magnetic pole centerline coincides with the rotor rotation center. The magnetic pole coil is in a state where it only bears radial centrifugal force and has no lateral centrifugal force, which fundamentally eliminates the outward turning force of the magnetic pole coil and solves the problem of excessive deformation of the magnetic pole coil.

[0020] 2. Through the structural design of this invention, the magnetic pole coil has no lateral centrifugal force, eliminating the need for inter-pole supports and magnetic pole shrouds, and other magnetic pole coil fixing components. This simplifies the magnetic pole structure and improves the overall safety of the magnetic poles. Furthermore, it greatly improves the later-stage maintenance and repair work of the magnetic poles in the power plant.

[0021] 3. Since there is no need to install a magnetic pole coil fixing component, the heat dissipation area outside the magnetic pole coil will be increased, thereby improving the thermal load bearing capacity of the magnetic pole.

[0022] 4. In this invention, the included angle δ is the same as the rotation angle a of the magnetic pole shoe. Furthermore, it is related to the weight of the magnetic pole coil and the cantilever stiffness of the magnetic pole shoe. This included angle δ can be adaptively adjusted for different types of magnetic pole structures to ensure that the magnetic pole coil has no lateral centrifugal force. Attached Figure Description

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, wherein:

[0024] Figure 1 This is a schematic diagram of the structure of the present invention;

[0025] Figure 2 This is a schematic diagram of the connection structure of the present invention;

[0026] Figure 3 This is a schematic diagram showing the lateral deformation of the magnetic pole coil of the tower-shaped magnetic pole in this invention;

[0027] Marked in the image:

[0028] 1. Rotor center body; 2. Magnetic yoke; 3. Rotor center; 4. Magnetic pole shoe; 5. Magnetic pole body; 6. Magnetic pole coil; 7. Insulating support plate; 8. Insulating plate; 9. Connection point between magnetic pole shoe and magnetic pole body; 10. Extension line of magnetic pole coil centerline when the unit is static; 11. Extension line of magnetic pole coil centerline when the unit reaches rated speed. Detailed Implementation

[0029] Example 1

[0030] As a basic embodiment of the present invention, the present invention includes a magnetic pole structure for eliminating the lateral component force of the magnetic pole coil, comprising a magnetic pole coil 6, a magnetic pole shoe 4, and a magnetic pole body 5. The magnetic pole is fixed to the outside of the magnetic yoke 2, the magnetic yoke 2 is fixed to the rotor center body 1, and the rotor center body 1 rotates around the rotor center 3.

[0031] When the unit is static, the centerline of the magnetic pole coil 6 is perpendicular to the magnetic pole shoe 4 and parallel to the magnetic pole body 5. The intersection of the extension of the centerline of the magnetic pole coil 6 and the magnetic pole centerline is located on the outer diameter side of the rotor center 3. When the unit reaches its rated speed, the centerline of the magnetic pole coil 6 is perpendicular to the magnetic pole shoe 4 and forms an angle δ with the magnetic pole body 5. The intersection of the extension of the centerline of the magnetic pole coil 6 and the magnetic pole centerline is exactly located at the rotor center 3. At this time, the magnetic pole coil 6 is in a state where it only bears radial centrifugal force and has no lateral centrifugal force.

[0032] Example 2

[0033] In a preferred embodiment of the present invention, the present invention includes a magnetic pole structure for eliminating the lateral component force of the magnetic pole coil, comprising a magnetic pole coil 6, a magnetic pole shoe 4, and a magnetic pole body 5. When the unit is static, the center line of the magnetic pole coil 6 is perpendicular to the magnetic pole shoe 4 and parallel to the magnetic pole body 5; the intersection of the extension of the center line of the magnetic pole coil 6 and the magnetic pole center line is located on the outer diameter side of the rotor center 3. Initially, the magnetic pole coil 6 will have a lateral component force pointing towards the magnetic pole center, but as the rotor speed increases, the magnetic pole shoe 4 rotates around the junction point 9 of the magnetic pole shoe and the magnetic pole body under the action of its own and the centrifugal force of the magnetic pole coil 6, and the magnetic pole coil 6 will also rotate accordingly. When the unit reaches the rated speed, the rotation angle of the magnetic pole shoe 4 is α; the center line of the magnetic pole coil 6 is perpendicular to the magnetic pole shoe 4 and has an angle δ with the magnetic pole body 5, the angle δ being the same as the rotation angle α of the magnetic pole shoe 4. At this time, the intersection of the extension of the center line of the magnetic pole coil 6 and the magnetic pole center line is exactly located at the rotor center 3.

[0034] The rotation angle α and the included angle δ are related to the weight of the magnetic pole coil 6 and the cantilever stiffness of the magnetic pole shoe 4.

[0035] Example 3

[0036] In another preferred embodiment of the present invention, the present invention includes a magnetic pole structure for eliminating the lateral component force of the magnetic pole coil, comprising a magnetic pole coil 6, a magnetic pole shoe 4, and a magnetic pole body 5. When the unit is static, the center line of the magnetic pole coil 6 is perpendicular to the magnetic pole shoe 4 and parallel to the magnetic pole body 5; the intersection of the extension of the center line of the magnetic pole coil 6 and the magnetic pole center line is located on the outer diameter side of the rotor center 3. When the unit reaches its rated speed, the center line of the magnetic pole coil 6 is perpendicular to the magnetic pole shoe 4 and forms an angle δ with the magnetic pole body 5; the intersection of the extension of the center line of the magnetic pole coil 6 and the magnetic pole center line is exactly located at the rotor center 3.

[0037] The included angle δ is calculated as follows:

[0038] δ=GL 2 / 2EI

[0039] Wherein, G is the sum of the side weight of the magnetic pole coil 6 and the cantilever weight of the magnetic pole shoe 4, L is the vertical distance from the center of gravity of the magnetic pole coil 6 to the magnetic pole body 5, E is the elastic modulus of the material of the magnetic pole shoe 4. Since the magnetic pole core is mostly a laminated structure, the elastic modulus of the material of the magnetic pole shoe 4 needs to be corrected in the specific application process; I is the moment of inertia of the cross section of the cantilever section of the pole shoe.

[0040] Example 4

[0041] As the preferred embodiment of the present invention, the present invention includes a magnetic pole structure for eliminating the lateral component force of a magnetic pole coil, comprising a magnetic pole core and a magnetic pole coil 6. The magnetic pole core includes a magnetic pole body 5 and a magnetic pole shoe 4, which are designed as a single unit, mostly made of thin steel plate by stamping or laser cutting, and are combined into a whole by a magnetic pole tensioning screw. Magnetic pole pressure plates are often used to press the magnetic pole laminations together at both ends, and the tensioning screw is fixed to the magnetic pole pressure plates. The magnetic pole coil 6 is fitted onto the magnetic pole core, with its top surface separated from the magnetic pole shoe 4 by an insulating support plate 7, maintaining a parallel and close relationship between the two. A certain electrical distance is maintained between the side of the magnetic pole and the side of the pole body. To prevent the magnetic pole coil 6 from shifting, an insulating plate 8 is inserted between them, and the insulating plate 8 is covered with felt to make it more tightly packed.

[0042] Refer to the instruction manual appendix Figure 2 The magnetic pole is fixed on the outside of the magnetic yoke 2, the magnetic yoke 2 is fixed on the rotor center body 1, and the rotor center body 1 rotates around the rotor center 3.

[0043] Refer to the instruction manual appendix Figure 1 When the unit is static, the center line of the magnetic pole coil 6 is perpendicular to the magnetic pole shoe 4 and parallel to the magnetic pole body 5. The magnetic pole body 5 is no longer arranged in a centripetal manner, and the intersection of the extension line 10 of the magnetic pole coil center line and the magnetic pole center line when the unit is static is located on the outer diameter side of the rotor center 3.

[0044] As the rotor speed increases, the magnetic pole shoe 4 rotates around the junction point 9 between the magnetic pole shoe and the magnetic pole body under the centrifugal force of itself and the magnetic pole coil 6, and the magnetic pole coil 6 will also rotate accordingly. When the unit reaches the rated speed, the rotation angle of the magnetic pole shoe 4 is 'a', the center line of the magnetic pole coil 6 is perpendicular to the magnetic pole shoe 4, and has an angle δ with the magnetic pole body 5. The angle δ is the same as the rotation angle 'a'. At this time, the intersection of the extension line 11 of the magnetic pole coil center line when the unit reaches the rated speed and the magnetic pole center line is exactly located at the rotor center 3.

[0045] The design of the included angle δ is related to the weight of the magnetic pole coil 6 and the cantilever stiffness of the magnetic pole shoe 4. More specifically, the calculation method of the included angle δ is as follows:

[0046] δ=GL 2 / 2EI

[0047] G=G j +G x

[0048] Where G is the weight of the 6th side of the magnetic pole coil. j And magnetic pole shoes 4 cantilever weight G xThe sum of these values; L is the vertical distance from the centroid of the magnetic pole coil 6 to the magnetic pole body 5; I is the moment of inertia of the cantilever section of the pole shoe. E is the elastic modulus of the material of the magnetic pole shoe 4. Since the magnetic pole core is mostly a laminated structure, the elastic modulus of the material of the magnetic pole shoe 4 needs to be corrected in specific applications. Specifically, the elastic modulus of the overall steel can be 2.1e5MPa. After correction, the elastic modulus of the laminated magnetic pole is less than the elastic modulus of the overall steel, and can be 1.8~2.0e5MPa.

[0049] During the initial analysis, the magnetic pole coil 6 will have a lateral component force pointing towards the center of the magnetic pole. However, as the rotor speed increases, the magnetic pole shoe 4 rotates under the radial centrifugal force of the magnetic pole coil 6, and the magnetic pole coil 6 will also rotate accordingly. The intersection of the extension line of the center line of the magnetic pole coil 6 and the center line of the magnetic pole is exactly located at the rotor center 3. The magnetic pole coil 6 is in a state where it only bears radial centrifugal force, thus fundamentally eliminating the lateral component force problem of the magnetic pole coil 6 during normal operation, simplifying the magnetic pole structure, and improving the magnetic pole safety and maintenance convenience.

[0050] A simulation analysis of magnetic pole coil deformation was conducted for a pumped-storage unit with a rated capacity of 350MW and a rated speed of 500rpm. The yield strength of the magnetic pole laminations is 650MPa, and the tensile strength is 750MPa; the yield strength of the yoke laminations is 690MPa, and the tensile strength is 770MPa. A tower-shaped magnetic pole structure was adopted, as per the attached instruction manual. Figure 3 At rated speed, the magnetic pole coils are initially arranged centripetally. The magnetic pole coils will undergo lateral deformation as the pole shoes deform, with a lateral deformation of approximately 0.47 mm. Using the structure of this embodiment, the initial design of the magnetic pole coils allows its center of gravity to be offset by a small angle from the centripetal line, corresponding to a center of gravity offset of approximately 0.47 mm. As the magnetic pole coils undergo lateral deformation due to the pole shoes, its center of gravity coincides perfectly with the centripetal line, thus eliminating the lateral force on the magnetic pole coils.

[0051] In summary, any other corresponding modifications made by those skilled in the art after reading this invention document, without requiring creative mental effort, based on the technical solutions and concepts of this invention, are all within the scope of protection of this invention.

Claims

1. A magnetic pole structure for eliminating the lateral component force of a magnetic pole coil, comprising a magnetic pole coil (6), a magnetic pole shoe (4), and a magnetic pole body (5); characterized in that: When the unit is static, the center line of the magnetic pole coil (6) is perpendicular to the magnetic pole shoe (4) and parallel to the magnetic pole body (5); the intersection of the extension line of the center line of the magnetic pole coil (6) and the magnetic pole center line is located on the outer diameter side of the rotor center (3); when the unit reaches the rated speed, the center line of the magnetic pole coil (6) is perpendicular to the magnetic pole shoe (4) and has an angle δ with the magnetic pole body (5); the intersection of the extension line of the center line of the magnetic pole coil (6) and the magnetic pole center line is located exactly at the rotor center (3); the magnetic pole shoe (4) rotates around the junction point (9) of the magnetic pole shoe and the magnetic pole body under the centrifugal force of itself and the magnetic pole coil (6); when the unit reaches the rated speed, the rotation angle a of the magnetic pole shoe (4) is the same as the angle δ.

2. The magnetic pole structure for eliminating the lateral component force of a magnetic pole coil according to claim 1, characterized in that: The included angle δ is calculated as follows: δ=GL 2 / 2EI Wherein, G is the sum of the side weight of the magnetic pole coil (6) and the cantilever weight of the magnetic pole shoe (4), L is the vertical distance from the center of gravity of the magnetic pole coil (6) to the magnetic pole body (5), E is the elastic modulus of the material of the magnetic pole shoe (4), and I is the moment of inertia of the cross section of the cantilever segment of the pole shoe.

3. A magnetic pole structure for eliminating the lateral component force of a magnetic pole coil according to claim 2, characterized in that: When calculating the included angle δ, the elastic modulus E of the magnetic pole shoe (4) material is also corrected. The corrected elastic modulus E ranges from 1.8 to 2.0e5MPa.

4. A magnetic pole structure for eliminating the lateral component force of a magnetic pole coil according to claim 1, characterized in that: The top surface of the magnetic pole coil (6) is separated from the magnetic pole shoe (4) by an insulating plate (7).

5. A magnetic pole structure for eliminating the lateral component force of a magnetic pole coil according to claim 1, characterized in that: The side of the magnetic pole coil (6) is kept electrically at a distance from the magnetic pole body (5).

6. A magnetic pole structure for eliminating the lateral component force of a magnetic pole coil according to claim 5, characterized in that: An insulating plate (8) is provided between the side of the magnetic pole coil (6) and the magnetic pole body (5), and the insulating plate (8) is covered with felt.

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