CN113472098A

CN113472098A - Split type iron core structure

Info

Publication number: CN113472098A
Application number: CN202010241257.1A
Authority: CN
Inventors: 彭亮; 李延慧; 刘勇
Original assignee: Beijing Goldwind Science and Creation Windpower Equipment Co Ltd
Current assignee: Beijing Goldwind Science and Creation Windpower Equipment Co Ltd
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2021-10-01
Anticipated expiration: 2040-03-31
Also published as: CN113472098B

Abstract

The invention relates to a split type iron core structure which comprises a first punching sheet layer and a second punching sheet layer which are vertically overlapped along an axial direction, wherein the first punching sheet layer is formed by arranging first fan-shaped punching sheets and second fan-shaped punching sheets in the circumferential direction, the first fan-shaped punching sheets are arranged at the two circumferential ends of the first punching sheet layer, the second fan-shaped punching sheets are arranged between the two first fan-shaped punching sheets positioned at the two circumferential ends or a combination of the second fan-shaped punching sheets and the first fan-shaped punching sheets, the second punching sheet layer is formed by arranging third fan-shaped punching sheets in the circumferential direction, the second punching sheet layer is aligned with the first punching sheet layer in the axial direction, and gaps among the fan-shaped punching sheets in the first punching sheet layer are staggered with gaps among the fan-shaped punching sheets in the second punching sheet layer in the axial direction. By using two or three types of segmental punching sheets and through special arrangement, a split type iron core structure suitable for distributed windings can be constructed.

Description

Split type iron core structure

Technical Field

The invention relates to the technical field of wind power, in particular to a split type iron core structure, a stator iron core comprising the split type iron core structure and a wind generating set comprising the stator iron core.

Background

At present, the wind power market enters a bidding era, and the requirement of reducing the whole life cycle cost (namely LCoE) of a unit is increasingly highlighted. The upsizing of the plant is the most effective means for coping with this demand. The larger the unit power is, the larger the generator outer diameter of the direct-drive wind driven generator is, but as the motor outer diameter and weight slowly start to exceed road transportation limits (e.g. 4.6m, 85t), the transportation cost increases sharply, which brings great challenges to land transportation. The motor is transported to a project site in a split mode and then assembled and installed on the project site, and therefore the motor becomes an effective technical solution.

When a large motor is split, the stator core needs to be split at the same time. The split motor adopting concentrated windings is easy to realize the splitting of the iron core. Although the concentrated winding is adopted, the copper used for the winding can be reduced, the modularization manufacturing is easy, and the like, the defects also exist, such as larger harmonic wave generated by the concentrated winding, higher stray loss of the motor and the like. For example, for concentrated winding and split type iron core, if the iron core punching sheet is not in staggered layers, namely, two axially adjacent iron core punching sheets are not in staggered overlapping, fixed gaps exist on two sides of the circumference of each iron core punching sheet, so that the gaps existing in the iron core punching sheets of each layer are aligned in the axial direction, and further the magnetic resistance in the stator magnetic yoke magnetic circuit of the whole iron core is increased. If the iron core punching sheets are stacked in a staggered mode, compared with a mode without staggered stacking, a small magnetic resistance is introduced into the stator magnetic yoke.

Therefore, for the split core, it is desirable to use a split core structure suitable for distributed windings. However, for the conventional iron core formed by using the iron core punching sheets with the same structure, if the iron core punching sheets are staggered and stacked, the iron core punching sheets are not suitable for distributing windings and the split type iron core, because if the iron core punching sheets are staggered, the circumferential edges of the formed split type iron core are irregular in shape.

Disclosure of Invention

In view of the above problems in the prior art, the present invention aims to provide a split core structure suitable for distributed windings.

According to one aspect of the invention, a split iron core structure is provided, which includes a first punching sheet layer and a second punching sheet layer which are stacked up and down along an axial direction, the first punching sheet layer is formed by arranging first segmental punching sheets and second segmental punching sheets in the circumferential direction, the first segmental punching sheets are arranged at two ends of the first punching sheet layer in the circumferential direction, the second segmental punching sheets are arranged between the two first segmental punching sheets at the two ends of the circumferential direction, or a combination of the second segmental punching sheets and the first segmental punching sheets is arranged, the second punching sheet layer is formed by arranging third segmental punching sheets in the circumferential direction, the second punching sheet layer is aligned with the first punching sheet layer in the axial direction, and gaps between the segmental punching sheets in the first punching sheet layer are staggered with gaps between the segmental punching sheets in the second punching sheet layer in the axial direction.

Preferably, the indexing angle of the first segment punching sheet may be B1, the indexing angle of the second segment punching sheet may be B2, the indexing angle of the third segment punching sheet may be B3, and the size of B1 may be different from the sizes of B2 and B3.

Preferably, the yoke portions of the first segment, the second segment and the third segment may have open slots, and the open slots on the same segment may have the same opening direction.

Preferably, the opening directions of all the open grooves of the first punching layer may be inclined toward the first direction, and the opening directions of all the open grooves of the second punching layer may be inclined toward the second direction.

The opening directions of the open grooves of the first and second fan-shaped punching sheets can incline towards the first direction, and the opening direction of the open groove of the third fan-shaped punching sheet can incline towards the second direction.

Preferably, the indexing angle between adjacent open slots on each segment punching sheet may be a, where the indexing angle of the first segment punching sheet may be equal to 3A, the indexing angles of the second segment punching sheet and the third segment punching sheet may be equal to 2A, or the indexing angle of the first segment punching sheet may be equal to 2A, and the indexing angles of the second segment punching sheet and the third segment punching sheet may be equal to 3A.

Preferably, the second segment punching sheet and the third segment punching sheet have the same structure, and the second segment punching sheet can be reversely placed to obtain the third segment punching sheet when being stacked.

Preferably, on each segmental punching sheet, the distance from the opening groove close to the circumferential first end of the segmental punching sheet to the edge of the circumferential first end may be a1, the distance from the opening groove close to the circumferential second end to the edge of the circumferential second end may be a2, and a1+ a2 is a.

Preferably, a1 ═ 0.5A and a2 ═ 0.5A.

Preferably, a is 5 degrees, the indexing angle of the first segment punching sheet may be 15 degrees, and the indexing angles of the second segment punching sheet and the third segment punching sheet may be 10 degrees; or, a is 5 degrees, the indexing angle of the first segment may be 10 degrees, and the indexing angles of the second segment and the third segment may be 15 degrees.

Preferably, the first segment may be formed by laser cutting, and the second segment and the third segment may be molded.

According to another aspect of the present invention, a stator core is provided, which is formed by splicing the split core structures described above in the circumferential direction and the axial direction.

According to another aspect of the invention, a wind turbine generator set is provided, comprising a stator core as described above.

The split type iron core structure provided by the invention adopts two or three fan-shaped punching sheets, and can be constructed into the split type iron core structure suitable for distributed windings through special arrangement.

Through setting up special towards the sheet structure at every circumference both ends towards the lamella (i.e. iron core split department) to make the towards the sheet structure of the split department of the axially adjacent towards the lamella different, realize the effect of staggered lamination (i.e. make the gap between each towards the piece stagger between adjacent layer), and iron core split department can realize leveling and the terminal surface structure who aligns.

In addition, by adopting the fan-shaped punching sheet arrangement mode and the fan-shaped punching sheet structure, the simplification of a punching sheet die is facilitated, and the manufacturing cost is reduced.

Drawings

Figure 1 shows a schematic partial cross-sectional view of a prior art motor core structure;

fig. 2 shows a schematic diagram of a segment core punching sheet in the prior art;

fig. 3 shows a schematic view of three segmental laminations constituting a split core structure according to a first embodiment of the invention;

fig. 4 shows a schematic structural view of two adjacent punched plies according to a first embodiment of the invention;

fig. 5 shows a schematic view of three segmental laminations constituting a split core structure according to a second embodiment of the invention;

fig. 6 shows a schematic structural view of two adjacent punched sheet layers according to a second embodiment of the invention.

Description of reference numerals:

1-punching; 2-a stator support; 3-a fixed bond; 4-opening; 10-a first fan-shaped punching sheet; 11-open slots; 20-a second fan-shaped punching sheet; 21-an open slot; 30-a third fan-shaped punching sheet; 31-open slots; 100-a first punching layer; 200-second punching layer.

Detailed Description

In order that those skilled in the art will better understand the technical concept of the present invention, a detailed description of specific embodiments of the present invention will be given below with reference to the accompanying drawings, in which like reference numerals refer to like parts throughout.

In the existing iron core punching sheet structure of distributed windings, the iron core structure of a synchronous motor with megawatt level and above is generally shown in fig. 1 and fig. 2, and fixing keys 3 for fixing the punching sheet 1 of the iron core are generally uniformly distributed on the circumference of a stator support 2. The fixing key 3 has a generally dovetail-shaped cross section. The punching sheet 1 is generally a fan-shaped punching sheet, the yoke part is uniformly distributed with openings 4 with an indexing angle of 0.5A, wherein A represents the indexing angle between two openings 4 with the same opening direction, one side of the openings 4 is provided with a clamping groove matched with the dovetail-shaped section of the fixed key 3, and the other side is not provided with a clamping groove. The slot positions of the openings 4 are staggered next to each other. When the iron cores are laminated, the punching sheets 1 are sequentially arranged in the circumferential direction; when the next layer is formed, the punching sheets 1 are staggered by an angle of 0.5A in the circumferential direction; the circumferential side edges of the punching sheets 1 are provided with a certain misalignment C, and a clearance value of 2C exists between every two adjacent punching sheets in the laminated iron core. The staggered arrangement can ensure that gaps between adjacent punching sheets 1 are staggered between different layers, so that the flatness of iron core lamination is ensured, and the iron core after lamination can be reliably fixed in the fixed key 3 in the circumferential direction. The indexing angles B of all the punches 1 are 2A.

For the iron core structure with the iron core stamped sheets being stacked in a staggered manner, although the gaps between the adjacent stamped sheets 1 are staggered between different layers, if the split type iron core is formed, the end faces (i.e., the split positions of the iron core) at the two circumferential ends of the split type iron core are irregular, so that the split type iron core structure is not suitable for the split type iron core structure with distributed windings.

As shown in fig. 3 and 4, the present invention provides a split core structure suitable for a split stator of an electric motor, which is illustrated in fig. 4 by taking an example of dividing the stator into two halves in a circumferential direction, i.e., a split core structure has a semi-annular shape with an angle of 180 °. Each split core structure is formed by a plurality of punching sheet layers stacked in the axial direction, and each punching sheet layer comprises a plurality of segmental punching sheets arranged in the circumferential direction.

As shown in fig. 4, the split core structure may include a first punching sheet layer 100 and a second punching sheet layer 200 which are adjacent in the axial direction, the invention is described in the context of the adjacent first punching sheet layer 100 and second punching sheet layer 200, and when the motor stator needs to be stacked with more punching sheet layers, the structure of the first punching sheet layer 100 and the second punching sheet layer 200 is repeatedly stacked to form the required punching sheet layer structure. The invention provides that special segmental punching sheets are arranged at two circumferential ends of punching sheet layers of a split type iron core (namely the end parts of a split type structure), and the structure of the segmental punching sheets at the two circumferential ends of adjacent punching sheet layers (such as a second punching sheet layer) is different from the structure of the segmental punching sheets of the punching sheet layers (such as a first punching sheet layer), so that gaps between the segmental punching sheets in the circumferential direction are staggered among different punching sheet layers, the end surfaces of the two circumferential ends of each punching sheet layer are aligned and flat, and the split type structure which does not influence the electromagnetic performance of a stator is formed.

Specifically, in order to realize the stacking structure of the different punching layers, as shown in fig. 3 and 4, the split-type iron core structure provided by the invention can be formed by stacking three types of segmental punching. The first punching sheet layer 100 can be formed by arranging the first segmental punching sheets 10 and the second segmental punching sheets 20 in the circumferential direction, the first segmental punching sheets 10 can be arranged at both ends of the first punching sheet layer 100 in the circumferential direction, the second segmental punching sheets 20 are arranged between the two first segmental punching sheets 10 at both ends in the circumferential direction, or the combination of the second segmental punching sheets 20 and the first segmental punching sheets 10 is arranged, so that a complete split type iron core punching sheet layer is formed. The second punched sheet layer 200 may be formed by arranging the third segmental punched sheets 30 in the circumferential direction, the second punched sheet layer 200 may be aligned with the first punched sheet layer 100 in the axial direction, and the gaps between the segmental punched sheets in the first punched sheet layer 100 are staggered from the gaps between the segmental punched sheets in the second punched sheet layer 200 in the axial direction.

The indexing angle B1 of the first segment 10 may be different from the indexing angles B2 of the second segment 20 and B3 of the third segment 30.

Specifically, the radially inner side of the yoke portion of each

segment

10, 20, 30 is provided with an open slot for receiving a dovetail-shaped fixing key for fixing each segment to the stator frame. The indexing angle between adjacent slots on each segment is a, as shown in fig. 3. In addition, on each segmental punching sheet, the distance from the opening groove close to the circumferential first end (as shown in the figure, the left end) of the segmental punching sheet to the edge of the circumferential first end is a1, the distance from the opening groove close to the circumferential second end (as shown in the figure, the right end) to the edge of the circumferential second end is a2, and a1+ a2 is equal to a. Preferably, a1 and a2 are both 0.5A. That is, the distance a1 or a2 between two edges of each

segment

10, 20, 30 that do not form the complete indexing angle a is abutted against circumferentially adjacent segments of the same layer to form the complete indexing angle a in the circumferential direction.

In order to make the gap between each segmental punching sheet in the circumferential direction staggered between the adjacent upper punching sheet layer and the lower punching sheet layer during stacking, simultaneously make the open slots of each segmental punching sheet aligned in the axial direction as a whole and form the dovetail-shaped slot clamped with the dovetail-shaped fixed key, and make the end surfaces of the circumferential two ends of each punching sheet layer aligned in the axial direction, each segmental punching sheet provided by the invention meets the following conditions: the opening directions of all the open slots included in a single segment are all towards the same direction, that is, the opening directions of all the open slots of the first segment 10 are the same, the opening directions of all the open slots of the second segment 20 are the same, and the opening directions of all the open slots of the third segment 30 are the same. In the embodiment shown in fig. 3, the opening directions of the

open slots

11 and 21 of the first and second

segmental punches

10 and 20 are the same (as shown in fig. 3, the opening directions of the

open slots

11 and 21 are both substantially clockwise inclined), and the opening direction of the open slot 21 of the second segmental punch 20 is opposite to the opening direction of the open slot 31 of the third segmental punch 30 (as shown in fig. 3, the opening direction of the open slot 31 is substantially counterclockwise inclined); of course, the opening directions of the

open grooves

11 and 21 may be inclined counterclockwise, and the opening direction of the open groove 31 may be inclined clockwise. Meanwhile, the indexing angle B1 of the first segment punching sheet 10 is equal to 3A, and the indexing angles B2 of the second segment punching sheet 20 and B3 of the third segment punching sheet 30 are equal to 2A. Of course, the indexing angle B of each segment punching sheet is set to be the minimum split machining structure, and B1 is set to be equal to 6A, B2 is set to be equal to 4A, B3 is set to be equal to 4A of the segment punching sheet with the same multiple size according to the actual size of the indexing angle a of the stator core punching sheet of the motor and the machining conditions, so that the combined structure of different punching sheet structures of the split core can be realized.

By adopting the three segmental punching sheets, when the segmental punching sheets are stacked, as shown in fig. 4, the first punching sheet layer 100 of the split type iron core can be formed by combining and arranging the first segmental punching sheets 10 and the second segmental punching sheets 20 in the circumferential direction, the first segmental punching sheets 10 can be arranged at both ends of the first punching sheet layer 100 in the circumferential direction, and a plurality of second segmental punching sheets 20 or a combination of a plurality of second segmental punching sheets 20 and the first segmental punching sheets 10 is arranged at positions between both ends of the first punching sheet layer 100 in the circumferential direction, namely between the first segmental punching sheets 10 at both ends, so as to form the complete split type iron core. The second punching sheet layer 200 can be formed by the third fan-shaped punching sheets 30 which are arranged in a circumferential combined mode, the second punching sheet layer 200 is aligned with the first punching sheet layer 100 in the axial direction, and the two punching sheet layers form the same split type iron core structure. The split type iron core of the motor stator is arranged, the punching layers which are adjacent in the axial direction are different in the structure of the fan-shaped punching sheets at the two end parts of the split type structure, and the opening directions of the opening grooves of the punching sheets are opposite, so that the staggered arrangement of the upper layer and the lower layer is realized. Specifically, in the present invention, the indexing angle B1 of the first segment punching sheet 10 located at both ends of the first punching sheet layer 100 is 3A, and the indexing angle B3 of the third segment punching sheet 30 located at both ends of the second punching sheet layer 200 is 2A, the opening direction of the opening slot of the first segment punching sheet 10 is clockwise inclined, and the opening direction of the opening slot of the third segment punching sheet 30 is counterclockwise inclined, so that the gap between the segment punching sheets in the first punching sheet layer is axially staggered from the gap between the segment punching sheets in the second punching sheet layer.

Specifically, as shown in fig. 4, the core is divided into two pieces, each piece of the core is 180 degrees, that is, both the first punch layer 100 and the second punch layer 200 are 180 degrees, where a is 5 degrees, B1 is 3A 15 degrees, B2 is 2A 10 degrees, and B3 is 2A 10 degrees. In the

first punch sheet

100, 2 long first segment punching sheets 10 with an indexing angle of B1 ═ 15 degrees are respectively placed at both ends of the circumference of the first punch sheet 100, and 15 short second segment punching sheets 20 with an indexing angle of B2 ═ 10 degrees are placed at the rest positions, so that a combination of the long first segment punching sheets 10 and the short second segment punching sheets 20 can be placed between two long first segment punching sheets 10 at both ends of the circumference as long as the angle requirement is met. In addition, in the second punched sheet layer 200, 18 short third fan-shaped punched sheets 30 with an indexing angle B3 of 10 degrees may be placed.

At the same time, it is possible to achieve that the open slots of the individual segmental punches are generally aligned in the axial direction and form a dovetail-shaped slot.

This kind of arrangement, use a small amount of first segmental lamination 10 of long type relatively long, a great amount of relatively little short type second segmental lamination 20 and short type third segmental lamination 30, therefore, when processing the lamination, to the first segmental lamination 10 of long type that uses a small amount, can adopt the mode of laser cutting to form, and to short type second segmental lamination 20 and short type third segmental lamination 30 that uses a large amount, can only set up two punching moulds and just can realize the manufacturing of second segmental lamination 20 and third segmental lamination 30, through the shaping of two moulds like this, can process the lamination structure that is applicable to split type iron core.

In addition, optionally, because the opening directions of the open slots included in the second and third fan-shaped

punching sheets

20 and 30 are opposite, further, a mold may be provided to process the second and third fan-shaped

punching sheets

20 and 30, and when the second and third fan-shaped

punching sheets

20 and 30 are stacked, the second fan-shaped punching sheet 20 is turned over and used, so that the opening directions of the open slots are opposite, and thus the third fan-shaped punching sheet 30 is formed. Specifically, since the second segment 20 and the third segment 30 are basically the same, and only the opening directions of the open slots are different, when the segments are manufactured, only one segment of one structure may be manufactured, that is, for example, the third segment 30 is manufactured at the same time by using a mold for manufacturing the second segment 20, and the structures of the second segment 20 and the third segment 30 are the same at this time, and when the segments are stacked, part of the second segment 20 is placed in the reverse direction (placed in the upside down direction), and then the third segment 30 may be obtained. In this case, only two types of segmental punching sheets may be used to form a split core structure, for example, only the first segmental punching sheet 10 and the second segmental punching sheet 20 are used, the opening slot directions of the two segmental punching sheets are the same, in the first punching sheet layer 100, the first segmental punching sheet 10 is placed at both ends of the first punching sheet layer 100 in the circumferential direction, the second segmental punching sheet 20 or the combination of the second segmental punching sheet 20 and the first segmental punching sheet 10 is placed at the other positions, and in the second punching sheet layer 200, the second segmental punching sheets 20 are all placed in the reverse direction (i.e., corresponding to the structure of the third segmental punching sheet 30 described above). By the arrangement mode, the simplification of the die can be greatly facilitated, and the manufacturing cost can be reduced.

Further, fig. 5 and 6 show a second embodiment of the present invention. In fig. 5 and 6, a short first segment punching sheet 10, a long second segment punching sheet 20 and a long third segment punching sheet 30 are adopted, the indexing angle B1 of the first segment punching sheet 10 is equal to 2A, the indexing angle B2 of the second segment punching sheet 20 is equal to 3A, and the indexing angle B3 of the third segment punching sheet 30 is equal to 3A, when stacking, in the first punching sheet layer 10, the first segment punching sheet 10 is still placed at the circumferential two ends of the first punching sheet layer 10, and the second segment punching sheet 20 or the combination of the second segment punching sheet 20 and the first segment punching sheet 10 is placed at the rest positions between the circumferential two ends, and in the second punching sheet layer 30, the third segment punching sheet 30 is still placed in its entirety.

Specifically, as shown in fig. 6, the core is divided into two pieces, each piece of the core is 180 degrees, that is, both the first punch layer 100 and the second punch layer 200 are 180 degrees, where a is 5 degrees, B1 is 2A 10 degrees, B2 is 3A 15 degrees, and B3 is 3A 15 degrees. In the

first punch sheet

100, 2 short first segment punching sheets 10 with an indexing angle B1 of 10 degrees are respectively placed at two circumferential ends of the first punch sheet 100, next to the short first segment punching sheet 10 at one circumferential end (as shown in the figure, the upper side), and then one short first segment punching sheet 10 is placed, and then long second segment punching sheets 20 with an indexing angle B2 of 15 degrees are placed at other positions, for example, 10 long second segment punching sheets 20 are placed, and of course, other combinations of the short first segment punching sheets 10 and the long second segment punching sheets 20 can be used between the two short first segment punching sheets 10 at two circumferential ends as long as the angle requirement is met. In addition, 12 third fan-shaped punched sheets 30 with an indexing angle B3 of 15 degrees may be placed in the second punched sheet layer 200.

Compared with the first embodiment, in the second embodiment, the first segmental punching sheet 10 is shorter, and the second segmental punching sheet 20 and the third segmental punching sheet 30 are longer, so that a small number of short first segmental punching sheets 10 are adopted in the whole core structure, and a large number of long second segmental punching sheets 20 and third segmental punching sheets 30 are adopted, so that the number of gaps between the punching sheets in the circumferential direction is small, and the influence on the magnetic permeability at the yoke of the core is small.

As described above, the split core structure provided by the invention can be constructed by adopting two or three types of segmental laminations and specially arranging the segmental laminations, and is suitable for distributed windings.

Through setting up special towards the sheet structure at every circumference both ends towards the lamella (i.e. iron core split department) to the towards sheet structure of the split department of adjacent towards the lamella is different, realizes the effect of staggered lamination (i.e. makes the gap between each towards the piece stagger between adjacent layer), and iron core split department can realize leveling and the terminal surface structure who aligns.

While the embodiments of the present invention have been shown and described in detail, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents (e.g., various features of the invention can be combined to arrive at new embodiments). Such combinations, modifications and improvements are intended to be within the scope of the invention.

Claims

1. The utility model provides a split type iron core structure, includes that the first piece layer and the second of stack down dashes the piece layer from the axial, its characterized in that:

the first punching sheet layer (100) is formed by arranging a first fan-shaped punching sheet (10) and a second fan-shaped punching sheet (20) in the circumferential direction, the first fan-shaped punching sheets (10) are arranged at the two ends of the first punching sheet layer (100) in the circumferential direction, the second fan-shaped punching sheet (20) is arranged between the two first fan-shaped punching sheets (10) at the two ends in the circumferential direction, or the combination of the second fan-shaped punching sheet (20) and the first fan-shaped punching sheet (10) is arranged,

the second punching sheet layer (200) is formed by arranging third sector punching sheets (30) in the circumferential direction, the second punching sheet layer (200) is aligned with the first punching sheet layer (100) in the axial direction, and gaps between the sector punching sheets in the first punching sheet layer (100) are staggered with gaps between the sector punching sheets in the second punching sheet layer (200) in the axial direction.

2. The split core structure of claim 1, wherein the indexing angle of the first segment punching sheet (10) is B1, the indexing angle of the second segment punching sheet (20) is B2, the indexing angle of the third segment punching sheet (30) is B3, and the size of B1 is different from the sizes of B2 and B3.

3. The split type iron core structure according to claim 1, wherein open slots (11, 21, 31) are formed in yoke portions of the first segmental punching (10), the second segmental punching (20) and the third segmental punching (30), and opening directions of the open slots on the same segmental punching are the same.

4. The split core structure of claim 3, wherein the opening directions of all the open slots of the first punched sheet layer (100) are inclined toward a first direction, and the opening directions of all the open slots of the second punched sheet layer (200) are inclined toward a second direction.

5. The split core structure of claim 3, wherein the opening directions of the open slots of the first and second segmental punching sheets (10, 20) are inclined towards a first direction, and the opening direction of the open slot of the third segmental punching sheet (30) is inclined towards a second direction.

6. The split core structure of claim 3, wherein the indexing angle between adjacent slots on each segment is A,

the indexing angle of the first fan-shaped punching sheet (10) is equal to 3A, and the indexing angles of the second fan-shaped punching sheet (20) and the third fan-shaped punching sheet (30) are equal to 2A, or

The indexing angle of the first fan-shaped punching sheet (10) is equal to 2A, and the indexing angle of the second fan-shaped punching sheet (20) and the third fan-shaped punching sheet (30) is equal to 3A.

7. The split core structure of claim 1, wherein the second segment punching sheet (20) and the third segment punching sheet (30) have the same structure, and when the second segment punching sheet (20) is stacked, the third segment punching sheet (30) is obtained by reversely placing the second segment punching sheet (20).

8. The split core structure of claim 3, wherein, on each segmental punching sheet, the distance from the opening groove close to the circumferential first end of the segmental punching sheet to the edge of the circumferential first end is a1, and the distance from the opening groove close to the circumferential second end to the edge of the circumferential second end is a2, a1+ a2 ═ A.

9. The split core structure of claim 8, wherein a 1-0.5A and a 2-0.5A.

10. The split core structure according to claim 6, wherein A is 5 degrees, the indexing angle of the first segment punching sheet (10) is 15 degrees, and the indexing angles of the second segment punching sheet (20) and the third segment punching sheet (30) are 10 degrees;

or A is 5 degrees, the indexing angle of the first fan-shaped punching sheet (10) is 10 degrees, and the indexing angles of the second fan-shaped punching sheet (20) and the third fan-shaped punching sheet (30) are 15 degrees.

11. The split core structure of claim 1, wherein the first segment (10) is made by laser cutting, and the second segment (20) and the third segment (30) are molded.

12. A stator core, characterized by being formed by splicing the split core structure of any one of claims 1 to 11 in the circumferential direction and the axial direction.

13. A wind power plant comprising a stator core according to claim 12.