Low-voltage winding structure and transformer
By adopting a foil coil structure with central aluminum foil and end copper foil in the low-voltage winding of the transformer, the problems of large end losses and high temperature rise at the low-voltage winding are solved, and the effect of reducing losses and temperature rise is achieved, and the risk of insulation failure is avoided.
Patent Information
- Application Number
- CN202421354703.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-14
- Publication Date
- 2025-06-03
- Estimated Expiration
- 2034-06-14
AI Technical Summary
The end loss of the transformer's low-voltage winding ends is large and the temperature is increased, resulting in the risk of failure of interlayer insulation.
A low-voltage winding structure is designed, and a foil coil with a middle aluminum foil and an end copper foil is used. The resistivity of the metal foil layer of the two end coil sections is smaller than that of the middle coil sections, and conduction is achieved through the first and second conductive row connections.
The eddy current loss at the end of the low-voltage winding structure is reduced, the temperature rise is reduced, the interlayer insulation failure caused by overheating is avoided, and the loss of the low-voltage winding is reduced by about 10%.
Smart Images
Figure CN222939738U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of transformers, and particularly relates to a low-voltage winding structure and a transformer. Background Art
[0002] When the low-voltage winding of a transformer adopts a foil winding structure, due to the influence of the skin effect and leakage magnetic field on the foil winding structure, the current is mainly distributed at the ends of the low-voltage winding, resulting in a relatively large temperature rise at the end positions of the low-voltage winding and large end losses of the low-voltage winding. At present, the low-voltage winding is mainly produced with a single foil of the same material. Except for reducing the current density of the low-voltage winding, there is no effective control means for the end losses. Therefore, when selecting the winding current density, it is necessary to take into account both the end current density and the average current density of the winding to prevent the occurrence of the situation that the interlayer insulation fails due to overheating at the ends of the low-voltage winding during the operation of the transformer. Therefore, it is urgent to develop a low-voltage winding that can solve the problems of large end losses and large end temperature rise. Summary of the Utility Model
[0003] The main purpose of the utility model is to provide a low-voltage winding structure and a transformer, aiming to solve the technical problems of large end losses and large end temperature rise of the low-voltage winding.
[0004] To achieve the above purpose, a low-voltage winding structure proposed by the utility model includes a foil-type coil, a first conductive bar, and a second conductive bar; the foil-type coil includes a middle coil section and two end coil sections, one end coil section is located at one end of the middle coil section, and the other end coil section is located at the other end of the middle coil section; wherein, the metal foil layers of the end coil sections correspond to the metal foil layers of the middle coil section one by one, and the resistivity of the metal foil layers of the two end coil sections is less than the resistivity of the metal foil layers of the middle coil section; the first conductive bar is connected to the innermost metal foil layer of the middle coil section and the innermost metal foil layers of the two end coil sections; the second conductive bar is connected to the outermost metal foil layer of the middle coil section and the outermost metal foil layers of the two end coil sections.
[0005] Further, the width of the end coil section is in the range of 10 mm to 80 mm.
[0006] Further, the metal foil layer of the middle coil section is an aluminum foil, and the metal foil layers of the end coil sections are copper foils.
[0007] Further, the thickness of the metal foil layers of the two end coil sections is the same as the thickness of the metal foil layer of the middle coil section.
[0008] Further, in the axial direction, the gap between the metal foil layer of the middle coil section and the metal foil layer of the end coil section does not exceed 2 mm.
[0009] Further, both the first conductive bar and the second conductive bar are provided with lead-out ends, and the lead-out ends of the first conductive bar and the second conductive bar are both led out from the same end of the foil coil.
[0010] Further, a fixed jack is provided at one end of the first conductive bar on the side away from the lead-out end.
[0011] In a second aspect of the present invention, a transformer is disclosed, including a low-voltage winding structure described in the first aspect of the present invention.
[0012] The technical solution provided by the present invention may include the following beneficial effects:
[0013] In a low-voltage winding structure provided by the present invention, the resistivity of the metal foil layers of the two end coil sections is less than that of the metal foil layer of the middle coil section, so that the resistivity at both ends of the low-voltage winding structure is small. When the current is mainly distributed at the ends of the low-voltage winding structure, due to the small resistivity at the ends of the low-voltage winding structure, the effect of reducing eddy current loss is achieved. Therefore, the temperature rise at the end positions of the low-voltage winding structure is small, effectively avoiding the occurrence of the situation where the interlayer insulation fails due to overheating at the ends of the low-voltage winding during the operation of the transformer. Description of the Drawings
[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.
[0015] Figure 1 It is a schematic structural diagram of a low-voltage winding structure according to an embodiment of the present invention;
[0016] Figure 2 It is a front view of a low-voltage winding structure according to an embodiment of the present invention;
[0017] Figure 3 It is a schematic connection diagram of the first conductive bar and the foil coil of a low-voltage winding structure according to an embodiment of the present invention.
[0018] Explanation of the reference numerals in the drawings: 1 - foil coil, 11 - middle coil section, 12 - end coil section, 2 - first conductive bar, 21 - fixed jack, 3 - second conductive bar, 4 - lead-out end. Detailed implementation manners
[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0020] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.
[0021] In the present invention, unless otherwise clearly defined and limited, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.
[0022] In addition, in the present invention, descriptions such as "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and / or" appearing throughout the text is that it includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution that satisfies both A and B. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.
[0023] The following will be combined with Figures 1 to 3 , to describe a low-voltage winding structure according to an embodiment of the present invention, including a foil coil 1, a first conductive bar 2, and a second conductive bar 3;
[0024] The foil coil 1 includes a middle coil section 11 and two end coil sections 12. One end coil section 12 is located at one end of the middle coil section 11, and the other end coil section 12 is located at the other end of the middle coil section 11. Among them, the metal foil layers of the end coil section 12 correspond to those of the middle coil section 11 one by one, and the resistivity of the metal foil layers of the two end coil sections 12 is less than that of the metal foil layer of the middle coil section 11. Specifically and optionally, the foil coil 1 can be an integrally wound structure. When winding the foil, the metal foil layers of one end coil section 12, the metal foil layers of the middle coil section, and the metal foil layers of the other end coil section 12 are arranged in sequence along the axial direction, and then wound together into the turns of the foil coil 1, so that the metal foil layers of the end coil section 12 correspond to those of the middle coil section 11 one by one. Of course, in some other embodiments, the middle coil section 11 and the two end coil sections 12 can also be wound separately and finally assembled, and the foil coil 1 is welded to the first conductive bar 2 and the second conductive bar 3.
[0025] As Figure 3 shown, the first conductive bar 2 is connected to the innermost metal foil layer of the middle coil section 11 and the innermost metal foil layers of the two end coil sections 12. As Figure 2 shown, the second conductive bar 3 is connected to the outermost metal foil layer of the middle coil section 11 and the outermost metal foil layers of the two end coil sections 12. In this way, the middle coil section 11 and the two end coil sections 12 are electrically connected. More specifically, the first conductive bar 2 and the second conductive bar 3 can be copper bars or aluminum bars.
[0026] In a low-voltage winding structure provided by the present invention, the resistivity of the metal foil layers of the two end coil sections 12 is less than that of the metal foil layer of the middle coil section 11, so that the resistivity at both ends of the low-voltage winding structure is small. When the current is mainly distributed at the ends of the low-voltage winding structure, due to the small resistivity at the ends of the low-voltage winding structure, the effect of reducing eddy current loss is achieved. Therefore, the temperature rise at the end positions of the low-voltage winding structure is small, effectively avoiding the occurrence of the situation that the interlayer insulation fails due to overheating at the ends of the low-voltage winding during the operation of the transformer.
[0027] Compared with the low-voltage winding wound with the same metal foil layer in the prior art, through experimental tests, the low-voltage winding structure provided by the present invention can reduce the low-voltage winding loss by about 10%.
[0028] Preferably, the width w of the end coil section 12 is in the range of 10 mm to 80 mm. When the width w of the end coil section 12 is relatively small, the current density will be more concentrated at the ends of the middle coil section 11, resulting in an insignificant effect of reducing losses and temperature rise. When the width w of the end coil section 12 is too wide, although the current density will be more concentrated in the end coil section 12, the amount of the metal foil layer with a small resistivity is large, resulting in a significant increase in the manufacturing cost of the low-voltage winding structure. Through experimental tests and electromagnetic simulation calculations and analyses, when the width of the end coil section 12 is in the range of 10 mm to 80 mm, it can not only ensure the effect of reducing losses and temperature rise, but also avoid a significant increase in the cost of the low-voltage winding structure.
[0029] Specifically, the metal foil layer of the middle coil section 11 is an aluminum foil, and the metal foil layer of the end coil section 12 is a copper foil. Aluminum foil is a commonly used material with a low cost, but it has a large resistance and high losses; copper foil has a high cost and a small resistance. Using copper foil for the entire winding is a better solution, but the cost is very high. Therefore, in this embodiment, the middle of the foil-type coil 1 uses aluminum foil and the ends use copper foil. When the current is mainly distributed at the ends of the low-voltage winding structure, the temperature rise at the end positions of the low-voltage winding structure is small, effectively achieving the effect of reducing losses and avoiding the occurrence of the situation where the interlayer insulation fails due to overheating at the ends of the winding during the operation of the transformer, and the cost of the overall low-voltage winding structure increases within a reasonable range. Of course, in some other embodiments, the metal foil layer of the end coil section 12 can also be a silver foil.
[0030] Specifically, the thicknesses of the metal foil layers of the two end coil sections 12 are the same as the thickness of the metal foil layer of the middle coil section 11. In this way, the thicknesses of the end coil section 12 and the middle coil section 11 are approximately the same, making the overall thickness of the foil-type coil 1 uniform, so as to facilitate the high-voltage winding to be sleeved on the outer periphery of the low-voltage winding structure.
[0031] Preferably, in the axial direction, the gap between the metal foil layer of the middle coil section 11 and the metal foil layer of the end coil section 12 does not exceed 2 mm. By limiting the gap between the metal foil layer of the middle coil section 11 and the metal foil layer of the end coil section 12 to not exceed 2 mm, the overall length of the low-voltage winding structure can be prevented from increasing.
[0032] Specifically, both the first conductive busbar 2 and the second conductive busbar 3 are provided with lead-out ends 4, and the lead-out ends 4 of the first conductive busbar 2 and the lead-out ends 4 of the second conductive busbar 3 are both led out from the same end of the foil-type coil 1. By arranging the lead-out ends 4 of the first conductive busbar 2 and the second conductive busbar 3 on the same side of the foil-type coil 1, it is convenient for the first conductive busbar 2 and the second conductive busbar 3 to be connected to the leads.
[0033] More specifically, a fixed jack 21 is provided at one end of the first conductive row 2 away from the lead-out end portion 4. Since the first conductive row 2 is located in the inner circle of the foil-wound coil, when the foil is wound, the first conductive row 2 will first be fixed on the foil-winding mold and rotate with the foil-winding mold. For this reason, in this embodiment, a fixed jack 21 is provided on the first conductive row 2 for the limit protrusion of the foil-winding mold to insert, so as to facilitate the limit fixation of the first conductive row 2 and the foil-winding mold.
[0034] The present invention also discloses a transformer, including a low-voltage winding structure as described in any one of the above embodiments.
[0035] In the transformer provided by the present invention, the low-voltage winding structure includes a middle coil section 11 and two end coil sections 12. The resistivity of the metal foil layer of the two end coil sections 12 is less than that of the metal foil layer of the middle coil section 11, so that the resistivity at both ends of the low-voltage winding structure is small. When the current is mainly distributed at the ends of the low-voltage winding structure, due to the small resistivity at the ends of the low-voltage winding structure, the effect of reducing eddy current loss is achieved. Therefore, the temperature rise at the end positions of the low-voltage winding structure is small, effectively avoiding the occurrence of the situation that the interlayer insulation fails due to overheating at the low-voltage winding ends during the operation of the transformer.
[0036] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made under the concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.
Claims
1. A low voltage winding structure, characterized in that: including a foil coil, a first conductive row and a second conductive row; The foil coil comprises a middle coil section and two end coil sections, one of the end coil sections is located at one end of the middle coil section, and the other end coil section is located at the other end of the middle coil section; wherein the metal foil layer of the end coil section corresponds to the metal foil layer of the middle coil section one by one, and the resistivity of the metal foil layers of the two end coil sections is less than the resistivity of the metal foil layer of the middle coil section; The first conductive bar is connected to the innermost metal foil layer of the middle coil section and the innermost metal foil layers of the two end coil sections; the second conductive bar is connected to the outermost metal foil layer of the middle coil section and the outermost metal foil layers of the two end coil sections.
2. A low voltage winding structure according to claim 1, characterized in that: The width of the end coil section is in the range of 10 mm to 80 mm.
3. A low voltage winding structure according to claim 1, characterized in that: The metal foil layer of the middle coil section is aluminum foil, and the metal foil layer of the end coil section is copper foil.
4. A low voltage winding structure according to claim 1, characterized in that: The thickness of the metal foil layer of the two end coil sections is the same as the thickness of the metal foil layer of the middle coil section.
5. A low voltage winding structure according to claim 1, characterized in that: In the axial direction, the gap between the metal foil layer of the middle coil section and the metal foil layer of the end coil section does not exceed 2 mm.
6. A low voltage winding structure according to claim 1, characterized in that: The first conductive bar and the second conductive bar are both provided with lead-out ends, and the lead-out ends of the first conductive bar and the lead-out ends of the second conductive bar are both led out from the same end of the foil coil.
7. A low voltage winding structure according to claim 6, characterized in that: A fixing plug hole is provided at one end of the first conductive bar away from the lead-out end.
8. A transformer, characterized in that: It comprises a low voltage winding structure as described in any one of claims 1 to 7.