Foil winding of transformer
By adopting a symmetrical structure and insulating layer design in the transformer foil winding, the problems of eddy current loss and circulation loss are solved, the thinning of the conductive row and the heat dissipation are achieved, and the current carrying capacity and short-circuit resistance are improved.
Patent Information
- Application Number
- CN202510078262.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-17
- Publication Date
- 2025-05-02
AI Technical Summary
The existing foil windings of large-capacity, low-voltage, and high-current transformers have high eddy current loss and circulation loss in the leakage magnetic field, resulting in poor economic performance, large conductive discharge thickness and difficult heat dissipation, which limits the increase in current.
The transformer foil winding adopts a symmetrical structure. By setting an insulating layer between the foils and adopting a double-side or multiple-sided lead-out design on the conductive row, the eddy current loss and circulation loss are reduced, while increasing the heat dissipation area of the conductive row.
It significantly reduces the eddy current loss of the conductive discharge, reduces the temperature rise of the conductive discharge, improves the current carrying capacity, and improves the symmetry of the winding and the ability to resist short circuits.
Smart Images
Figure CN119920592A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of transformers, and in particular relates to a foil winding of a transformer. Background Art
[0002] With the rapid development of industrial power generation and electricity consumption and the implementation of the national dual-carbon strategy, the implementation of photovoltaic and wind power bidding policies will increase the unit capacity of new energy transformers, which will help reduce investment and operation and maintenance costs. Therefore, the capacity of transformers is getting larger and larger, from 2000kVA to more than 20000kVA, and the low-voltage current has risen to more than 10000A, but the transformer is required to be small in size, light in weight, high in energy efficiency and low in cost. At present, the windings of large-capacity, low-voltage, and high-current transformers usually use foil-wound windings on one side of the busbar, which requires a large busbar and two or more foils. Figure 1 As shown, a first conductive bar is arranged on the side wall of the core, and two foils are welded on the first conductive bar. The two foils are wound together in a counterclockwise direction along the side wall of the core. After the number of winding turns reaches the requirement, the ends of the two foils are welded to the same second conductive bar, thereby forming the winding of a low-voltage, high-current transformer. This transformer winding adopts foil winding with a single-side output of the winding busbar, which has the following problems: (1) In the leakage magnetic field, the thicker the foil, the greater the eddy current loss. The high-current foil winding adopts two thicker foils stacked together, and there is no insulation between the two foils, and the resistance is almost zero. Electrically, it is similar to a single thicker foil. The eddy current loss of the winding is very high and the economic performance is poor. If insulating paper is added between the two foils, such as Figure 2 As shown in the figure, the thickness of the foil is reduced by half. Adding insulating paper can limit the eddy current loss. However, because the positions of the two foils in the leakage magnetic field are different, the leakage magnetic field will cause a potential difference between the head and tail of the two foils, resulting in a circulating current between the two foils, which will bring about a circulating current loss, so that the overall additional loss will not be significantly reduced. (2) The large current bus is led out on one side, which requires a large-section conductive bus. Therefore, the conductive bus will become wider and thicker. The eddy current loss of the large-sized conductive bus in the leakage magnetic field will increase sharply, making it difficult to dissipate heat, and further limiting the current increase. Summary of the invention
[0003] In view of the current technical problems, the present invention aims to provide a transformer foil winding, which can solve the technical problem of how to limit eddy current loss and circulating current loss at the same time in the prior art.
[0004] In order to achieve the above object, the technical solution adopted by the present invention is:
[0005] A transformer foil winding comprises an iron core, and its structural features are: it also comprises 2n first conductive bars, 2n second conductive bars and 2n foils, n being an integer not less than 1; the 2n first conductive bars are symmetrically arranged along the circumferential side wall of the iron core, and the symmetry center is located on the axial center line of the iron core; each first conductive bar is provided with a foil, each foil is wound along the outer surface of the iron core, and the winding direction and the number of winding turns of each foil are the same; a first insulating layer is provided between two adjacent foils, and the foils on two symmetrical first conductive bars are symmetrically arranged about the axial center line of the iron core; the end of each foil is connected to the second conductive bar, and the first conductive bar and the second conductive bar at both ends of each foil are located on the same side of the iron core.
[0006] The foil material can be copper foil or aluminum foil. When preparing the foil winding of the transformer of the present invention, the number of turns of the foil needs to be determined according to the parameter requirements of the transformer electrical calculation. Since the two foils are separated by an insulating layer, and the eddy current loss is proportional to the square of the thickness of the foil, the eddy current loss inside the foil is significantly reduced. Since the foils on the two symmetrical first conductive bars are arranged in a symmetrical structure, the potential difference between the foils is eliminated, and the circulation loss between the foils is solved. By arranging an insulating layer between the foils to play an insulating role, and the first conductive bars are arranged symmetrically, the symmetry of the winding can be improved, and the product's short-circuit resistance can be improved. The prior art uses a single-side lead-out of a large current busbar, which requires a large-section conductive bar. The transformer foil winding of the present invention adopts a symmetrical structure arrangement, and 2n first conductive bars are led out on both sides or multiple sides. Due to the skin effect of the current, when the thickness of the conductive bar led out on both sides is half of the single-side lead-out structure, the current carrying capacity will be increased, and the eddy current loss can be reduced and the heat dissipation area can be increased. Therefore, the conductive bar used in the transformer foil winding of the present invention is thinner than that in the prior art, which can significantly reduce the eddy current loss of the conductive bar, reduce the temperature rise of the conductive bar, and improve the current carrying capacity.
[0007] Specifically, the cross-section of the core is circular.
[0008] Preferably, the first conductive row and the second conductive row at both ends of each foil are located on the same radius extension line of the iron core.
[0009] Preferably, the foil is connected to the first conductive bar and the second conductive bar by welding.
[0010] Specifically, a second insulating layer is provided on the circumferential side wall of the core, and 2n first conductive bars are arranged on the second insulating layer.
[0011] Preferably, the first insulating layer is made of insulating paper. The insulating paper is arranged between the foils to play an insulating role and prevent short circuits between two adjacent foils.
[0012] Compared with the prior art, the present invention has the following beneficial effects:
[0013] 1. The transformer foil winding of the present invention solves the technical problems of eddy current loss and circulating current loss by adopting a symmetrical structure and adding an insulating layer between the foil materials.
[0014] 2. The transformer foil winding of the present invention uses a thinner conductive bar than the prior art, which significantly reduces the eddy current loss of the conductive bar, reduces the temperature rise of the conductive bar, and improves the current carrying capacity.
[0015] 3. The transformer foil winding of the present invention improves the symmetry of the winding and enhances the product's ability to resist short circuits. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a schematic diagram of the transformer foil winding structure of the prior art;
[0017] Figure 2 yes Figure 1 Schematic diagram of transformer foil winding structure with an insulating layer added between foil materials;
[0018] Figure 3 is a schematic diagram of the transformer foil winding structure in the first embodiment of the present invention;
[0019] Figure 4 It is a schematic diagram of the transformer foil winding structure in the second embodiment of the present invention.
[0020] In the figure
[0021] 1-iron core, 2-first conductive row, 3-foil, 4-second conductive row, 5-first insulating layer, 6-second insulating layer. DETAILED DESCRIPTION
[0022] The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. For the convenience of description, if the words "upper", "lower", "left" and "right" appear in the following, they only indicate that the upper, lower, left and right directions are consistent with the drawings themselves, and do not limit the structure.
[0023] Embodiment 1
[0024] like Figure 3As shown, a transformer foil winding of the present embodiment includes an iron core 1, two first conductive bars 2, two second conductive bars 4 and two foils 3. The first conductive bars 2 and the second conductive bars 4 are both plate-shaped conductive bars, and the foils 3 used are copper foils. The cross-sectional shape of the iron core 1 is circular, and a second insulating layer 6 is provided on the circumferential side wall of the iron core 1. The two first conductive bars 2 are symmetrically arranged on the left and right sides of the iron core 1, and the center of symmetry is located on the axial center line of the iron core 1. A foil 3 is provided on each first conductive bar 2, and each foil 3 is wound along the outer surface of the iron core 1, the winding direction is counterclockwise, the number of winding turns is two, and the two foils 3 are symmetrically arranged about the axial center line of the iron core 1. A first insulating layer 5 is provided between two adjacent foils 3, and the first insulating layer 5 is made of insulating paper. The end of each foil 3 is connected to the second conductive bar 4, and the foil 3 is connected to the first conductive bar 2 and the second conductive bar 4 by welding. The first conductive bar 2 and the second conductive bar 4 at both ends of each foil 3 are located on the same side of the core 1 , and the first conductive bar 2 and the second conductive bar 4 at both ends of each foil 3 are located on the same extended radius line of the core 1 .
[0025] The transformer foil winding preparation method of this embodiment adopts the following steps:
[0026] S1, respectively arrange first conductive bars 2 on the left and right side walls of the core 1, and weld a foil 3 on the first conductive bar 2 on the right side;
[0027] S2, the foil material 3 in step S1 is wound 180° counterclockwise along the surface of the core 1, and then another foil material 3 is welded on the first conductive bar 2 on the left side wall of the core 1, and the foil material 3 on the first conductive bar 2 on the left side is located on the inner side of the foil material 3 in step S1; the two foil materials 3 are wound together for one circle +180°, and the second conductive bar 4 is welded on the foil material 3 in step S1, and the foil material 3 located on the inner side is further rotated 180° and then welded to the second conductive bar 4; during the winding process of the foil materials 3, a first insulating layer 5 is arranged between adjacent foil materials 3.
[0028] Example 2
[0029] like Figure 4As shown, a transformer foil winding of the present embodiment includes an iron core 1, four first conductive bars 2, four second conductive bars 4 and four foils 3. The first conductive bars 2 and the second conductive bars 4 are both plate-shaped conductive bars, and the foils 3 used are copper foils. The cross-sectional shape of the iron core 1 is circular, and a second insulating layer 6 is provided on the circumferential side wall of the iron core 1. The four first conductive bars 2 are symmetrically arranged on the left and right sides and the upper and lower sides of the iron core 1, and the symmetry center is located on the axial center line of the iron core 1. A foil 3 is provided on each first conductive bar 2, and each foil 3 is wound along the outer surface of the iron core 1, and the winding direction is counterclockwise, and the number of winding turns is two turns. The four foils 3 are symmetrically arranged about the axial center line of the iron core 1. A first insulating layer 5 is provided between two adjacent foils 3, and the first insulating layer 5 is made of insulating paper. The end of each foil 3 is connected to the second conductive bar 4, and the foil 3 is connected to the first conductive bar 2 and the second conductive bar 4 by welding. The first conductive bar 2 and the second conductive bar 4 at both ends of each foil 3 are located on the same side of the core 1 , and the first conductive bar 2 and the second conductive bar 4 at both ends of each foil 3 are located on the same extended radius line of the core 1 .
[0030] The transformer foil winding preparation method of this embodiment adopts the following steps:
[0031] S1, respectively arrange first conductive bars 2 on the left and right sides and upper and lower side walls of the core 1, and weld a first foil 3 on the first conductive bar 2 on the right side;
[0032] S2, winding the foil 3 in step S1 by 90° counterclockwise along the surface of the core 1, and then welding a second foil 3 on the first conductive bar 2 on the upper side wall of the core 1, and the second foil 3 is located on the inner side of the foil 3 in step S1; after winding the two foils 3 together by 90°, welding a third foil 3 on the first conductive bar 2 on the left side wall of the core 1, and the third foil 3 is arranged on the inner side of the second foil 3; after winding the three foils 3 together by 90°, welding a fourth foil 3 on the first conductive bar 2 on the lower side wall of the core 1, and the fourth foil 3 It is arranged on the inner side of the third foil 3; the four foils 3 are wound together for one circle +90°, and the first second conductive row 4 is welded on the first foil 3; the foil 3 located on the inner side continues to rotate 90°, and the second second conductive row 4 is welded on the second foil 3; the foil 3 located on the inner side continues to rotate 90°, and the third second conductive row 4 is welded on the third foil 3; the foil 3 located on the inner side continues to rotate 90°, and the fourth second conductive row 4 is welded on the fourth foil 3; during the winding process of the foils 3, a first insulating layer 5 is arranged between adjacent foils 3.
[0033] The contents explained in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the invention, and are not used to limit the scope of the invention. After reading the present invention, various equivalent forms of modifications to the embodiments by those skilled in the art fall within the scope defined by the claims attached to the present invention.
Claims
1. A transformer foil winding, comprising an iron core (1), characterized in that: It also includes 2n first conductive rows (2), 2n second conductive rows (4) and 2n foils (3), where n is an integer not less than 1; 2n first conductive bars (2) are symmetrically arranged along the circumferential side wall of the iron core (1), and the center of symmetry is located on the axial center line of the iron core (1); A foil material (3) is provided on each first conductive row (2), each foil material (3) is wound along the outer surface of the iron core (1), and the winding direction and number of windings of each foil material (3) are the same; a first insulating layer (5) is provided between two adjacent foil materials (3), and the foil materials (3) on two symmetrical first conductive rows (2) are symmetrically arranged about the axial center line of the iron core (1); The end of each foil (3) is connected to the second conductive bar (4), and the first conductive bar (2) and the second conductive bar (4) at both ends of each foil (3) are located on the same side of the iron core (1).
2. The transformer foil winding according to claim 1, characterized in that: The cross-sectional shape of the core (1) is circular.
3. The transformer foil winding according to claim 2, characterized in that: The first conductive row (2) and the second conductive row (4) at the two ends of each foil material (3) are both located on the same extended radius line of the iron core (1).
4. The transformer foil winding according to claim 1, characterized in that: The foil (3) is connected to the first conductive row (2) and the second conductive row (4) by welding.
5. The transformer foil winding according to claim 1, characterized in that: A second insulating layer (6) is provided on the circumferential side wall of the iron core (1), and 2n first conductive rows (2) are arranged on the second insulating layer (6).
6. The transformer foil winding according to claim 1, characterized in that: The first insulating layer (5) is made of insulating paper.