A multi-stage three-dimensional wound iron core structure

Abstract

This utility model discloses a multi-stage three-dimensional wound iron core structure, including a three-dimensional wound iron core assembly. The assembly consists of three identical single-frame wound iron cores connected in pairs to form an equilateral triangle layout. Each single-frame wound iron core is constructed by nesting n-level silicon steel sheets from the inside out. The cross-section of the first-level silicon steel sheet of the single-frame wound iron core is a heptagon with seven points concentric. The cross-sections of the second to nth-level silicon steel sheets are pentagons with three points concentric and the remaining two points on a common side line. This common side line passes through the center of the circumcircle and forms a 30° angle with the horizontal plane. By optimizing the structure of each level of silicon steel sheet in the single-frame wound iron core, the filling coefficient of the single-frame wound iron core is increased from the existing 0.87-0.90 to over 0.98. The cross-sectional area utilization rate of the iron core column is increased by more than 15%, which can reduce the weight of the three-dimensional wound iron core by about 15%-20%, saving costs and meeting the current requirements for no-load loss, noise, and no-load current balance.

Description

Technical Field

[0001] This utility model relates to the field of transformer technology, and in particular to a multi-stage three-dimensional wound core structure. Background Technology

[0002] The three-dimensional wound core of a transformer has the characteristics of reducing no-load loss and noise, and can be applied to photovoltaic, wind power, urban networks and industrial scenarios. The three-dimensional wound core is composed of three single-frame wound cores with the same geometric dimensions assembled into an equilateral triangular three-dimensional structure. Due to the limitations of existing processing technology, the trade-off between performance and efficiency, and considerations of economy and practicality, the silicon steel sheets that make up the single-frame wound core are usually designed as trapezoidal structures and then assembled together. For example, the Chinese invention patent with publication number CN107146709A and patent name "Single-phase wound core four-segment seven-level equal length cutting method" has a first-level inclined strip, a second-level inclined strip, a third-level inclined strip, a fourth-level straight strip, a fifth-level inclined strip, a sixth-level inclined strip and a seventh-level inclined strip. After a series of dimensional designs, they are wound in sequence and at the beginning and end by a core winding machine to form a single-phase wound core, and the core cross-section is a seven-level trapezoidal cross-section.

[0003] However, the existing technology still has the following drawbacks:

[0004] 1. Existing three-dimensional wound iron cores typically use silicon steel strips with a trapezoidal cross-section. Due to the characteristics of the trapezoidal structure, the first-level silicon steel strip has only four external connection points on the same outer circle, while the remaining levels of silicon steel strip have only two external connection points on the same outer circle. This results in the filling system of the iron core column during binding and fixing only reaching 0.87-0.90, which cannot meet the current requirements for no-load loss, noise, and no-load current balance. When it is necessary to reduce no-load loss, the only way is to increase the cross-sectional area of ​​the single-frame wound iron core, which will inevitably increase the total height and volume of the three-dimensional wound iron core and increase production costs.

[0005] 2. The existing trapezoidal silicon steel sheet core column has insufficient filling coefficient, the splicing and binding between single-frame wound cores and the binding between multiple levels of silicon steel sheets in the single-frame wound core are not strong enough, resulting in the accumulation of air gaps between phases and between stages, which affects the stability and reliability of the transformer in daily operation.

[0006] 3. Inadequate assembly and insulation design between the single-frame wound cores in the existing three-dimensional wound core system leads to excessively high magnetic flux density in the yoke of each single-frame wound core, causing oversaturation and increasing the no-load loss of the core. Utility Model Content

[0007] In order to overcome the shortcomings of the existing technology, the purpose of this utility model is to provide a multi-level three-dimensional wound iron core structure.

[0008] The purpose of this utility model is achieved by the following technical solution: a multi-level three-dimensional coiled iron core structure, including a three-dimensional coiled iron core group, wherein the three-dimensional coiled iron core group is composed of three identical single-frame coiled iron cores bound together in pairs and forming an equilateral triangle layout, wherein the single-frame coiled iron core is composed of n-grade silicon steel sheets fitted from the inside to the outside;

[0009] The cross-section of the first-stage silicon steel sheet of the single-frame coiled iron core is a heptagon with seven points concentric.

[0010] The cross-section of the second-grade silicon steel sheet to the nth-grade silicon steel sheet is a pentagon with three points on a common circle and the other two points on a common side line. This common side line passes through the center of the circumcircle and forms a 30° angle with the horizontal plane.

[0011] Furthermore, the cross-sectional structure of the first-grade silicon steel sheet to the nth-grade silicon steel sheet is determined by the following calculation formula:

[0012] (n-3)α+4β+θ=120°, where α is the central angle between two points on the circumcircle of the second-level silicon steel sheet to the (n-2)th-level silicon steel sheet, β is the central angle between two points on the circumcircle of the (n-1)th-level silicon steel sheet, θ is the central angle between two points on the circumcircle of the nth-level silicon steel sheet, and the first-level silicon steel sheet has an initial included angle α0, where α0 is equal to α.

[0013] Furthermore, in the calculation formula for the cross-sectional structure of the first-grade silicon steel sheet to the nth-grade silicon steel sheet, when n=7, α0=13.5°, α=13.5°, β=13.5°, and θ=12°.

[0014] Furthermore, the gap between the first-grade silicon steel sheet and the circumscribed circle is ≤0.05mm, and the gap between the second-grade to seventh-grade silicon steel sheets and the circumscribed circle is ≤0.1mm.

[0015] Furthermore, the multi-level three-dimensional wound iron core structure also includes polyester glass insulation tape and core column binding tape. The core columns of the three single-frame wound iron cores are assembled in pairs and then bound together by the polyester glass insulation tape, and several core column binding tapes are tied to the outside of the polyester glass insulation tape.

[0016] Furthermore, the multi-level three-dimensional wound core structure also includes yoke binding straps, and each level of silicon steel sheet in the single-frame wound core is connected to each other by several of the yoke binding straps.

[0017] Furthermore, the single-frame coiled iron core has a bonding portion, the bonding portions of the two assembled single-frame coiled iron cores are bonded together, and a composite insulation layer with a thickness of 0.05-0.15mm is placed between the bonding portions of the two.

[0018] Furthermore, the mating portion of the single-frame coiled iron core is provided with a first protrusion, and the mating portion of another single-frame coiled iron core that cooperates with it is provided with a corresponding first groove.

[0019] Furthermore, the equilateral triangular layout of the three-dimensional coiled iron core assembly is formed by connecting the centers of the circumcircles of the core columns of each single-frame coiled iron core.

[0020] Furthermore, the mating surface of the odd-numbered silicon steel sheets is provided with a second protrusion, and the mating surface of the even-numbered silicon steel sheets is provided with a second groove that matches the second protrusion.

[0021] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0022] (1) The embodiments of this application optimize the structure of each level of silicon steel sheet of the single-frame coiled iron core, thereby improving the filling coefficient of the single-frame coiled iron core. The cross-section of the first level coiled iron core is designed as a heptagon, with all seven points located on the same circumcircle. The cross-sections of the second to seventh level coiled iron cores are designed as pentagons, with three points located on the same circumcircle. Without increasing the height and volume of the three-dimensional coiled iron core, the filling coefficient is increased from the existing 0.87-0.90 to more than 0.98. The utilization rate of the cross-sectional area of ​​the iron core column is increased by more than 15%, and the weight of the three-dimensional coiled iron core can be reduced by about 15%-20%. This saves costs and meets the current requirements for no-load loss, noise and no-load current balance.

[0023] (2) By setting a first protrusion and a first groove on the mating part of the two single-frame coiled iron cores, the magnetic flux density of the iron core column is evenly distributed by the combination of composite insulation layer and protrusion and groove, the magnetic circuit length is extended, magnetic saturation is avoided, and the no-load loss is reduced by at least 12%.

[0024] (3) By setting the second protrusion and the second groove on the odd and even number of silicon steel sheets of each single frame coiled iron core, combined with the equilateral triangle layout of the three-dimensional coiled iron core group and the interlocking of the protrusion and groove meshing stages of the single frame coiled iron core, the lateral displacement is eliminated, the phase-to-phase cumulative air gap is further reduced, and the geometric accuracy of the equilateral triangle layout is improved. Attached Figure Description

[0025] Figure 1 This is a front view of a single-frame wound iron core of a multi-level three-dimensional wound iron core structure in a preferred embodiment of this utility model;

[0026] Figure 2 for Figure 1 Cross-sectional view after being cut along the AA direction;

[0027] Figure 3 This is a three-dimensional schematic diagram of a three-dimensional wound core assembly with a multi-level three-dimensional wound core structure in a preferred embodiment of the present invention;

[0028] Figure 4 This is a schematic cross-sectional view of the multi-level three-dimensional wound iron core structure after two single wound iron cores are assembled together in a preferred embodiment of the present invention.

[0029] Figure 5 This is a top view of the three-dimensional wound core assembly of the multi-level three-dimensional wound core structure in a preferred embodiment of the present invention;

[0030] Figure 6 This is a cross-sectional schematic diagram of the odd-numbered and even-numbered silicon steel sheets of the single-frame wound core of the multi-level three-dimensional wound core structure in a preferred embodiment of the present invention, showing that the mating surfaces of the odd-numbered and even-numbered silicon steel sheets are provided with a second protrusion and a second groove respectively.

[0031] Figure 7 This is a cross-sectional schematic diagram showing the first protrusion and the first groove on the mating part of the two single-type coiled iron cores of the multi-level three-dimensional coiled iron core structure in a preferred embodiment of the present invention.

[0032] In the picture:

[0033] 10. Three-dimensional coiled iron core assembly;

[0034] 20. Single-frame coiled iron core; 201. First-grade silicon steel sheet; 202. Second-grade silicon steel sheet; 203. Third-grade silicon steel sheet; 204. Fourth-grade silicon steel sheet; 205. Fifth-grade silicon steel sheet; 206. Sixth-grade silicon steel sheet; 207. Seventh-grade silicon steel sheet; 208. Adhesive part; 2081. First protrusion; 2082. First groove; 209. Second protrusion; 2010. Second groove; 2011. Iron core column; 2012. Iron yoke part;

[0035] 30. Iron yoke binding straps;

[0036] 40. Polyester-glass insulating tape;

[0037] 50. Heart-pillar ligation strap;

[0038] 60. Composite insulation layer;

[0039] 70. Metal grounding plate;

[0040] Y, circumcircle; L, common edge. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0042] like Figure 1-7As shown, a multi-level three-dimensional wound core structure can be applied to photovoltaic, wind power, urban networks, and industrial applications. This multi-level three-dimensional wound core structure includes a three-dimensional wound core assembly 10, which is connected in pairs by three identical single-frame wound cores 20. The overall height of each single-frame wound core 20 is approximately 35mm, and its width is approximately 22mm. The single-frame wound cores 20 are symmetrically distributed at 120°, forming an equilateral triangle layout.

[0043] Each single-frame wound iron core 20 is equipped with a metal grounding plate 70 located at 1 / 3 radius from the center of the iron core column 2011. The metal grounding plate 70 can be made of copper foil, and its thickness is approximately 0.4 mm, width is 6 mm, and length is 18 mm. The metal grounding plate 70 is welded and fixed to the outer silicon steel sheet. The welding end of the metal grounding plate 70 is designed with a barbed structure, and the insertion depth is set according to actual needs. The metal grounding plates 70 are evenly distributed on the three-dimensional wound iron core structure with an equilateral triangular layout, solving the problem of local overheating caused by poor welding of traditional grounding plates. Figure 5 As shown.

[0044] Each single-frame coiled iron core 20 is composed of n-grade silicon steel sheets nested from the inside out. For example, n=7, meaning there are a total of first-grade silicon steel sheets 201, second-grade silicon steel sheets 202, third-grade silicon steel sheets 203, fourth-grade silicon steel sheets 204, fifth-grade silicon steel sheets 205, sixth-grade silicon steel sheets 206, and seventh-grade silicon steel sheets 207. Among the silicon steel sheets of each grade in the single-frame coiled iron core 20, the thickness and width of the outer silicon steel sheets are greater than those of the inner silicon steel sheets. For example, the outer silicon steel sheet is approximately 0.4 mm thick and 13 mm wide, while the inner silicon steel sheet is approximately 0.3 mm thick and 11 mm wide.

[0045] During assembly, the first-level silicon steel sheet 201 is the innermost layer, and then the sheets are sequentially fitted outwards until the inner wall of the nth-level silicon steel sheet is tightly attached to the outer wall of the (n-1)th-level silicon steel sheet. After assembly, the second-level silicon steel sheet 202 to the nth-level silicon steel sheet have a common edge line L, which forms a 30° angle with the horizontal plane. When the two single-frame rolled iron cores 20 are combined, their common edge lines L are in contact with each other. The complete overlap of the common edge lines L makes the magnetic resistance between the three phases consistent, and the difference in the three-phase no-load current is ≤1.5%.

[0046] Among them, the first-grade silicon steel sheet 201 has a heptagonal cross-section, with its seven points located on the same circumcircle Y; the second to seventh-grade silicon steel sheets 207 have a pentagonal cross-section, with three points located on the same circumcircle Y, and the other two points located on a common line L passing through the center of the circle, as shown below. Figure 2 As shown. Through the structural design of the first-stage silicon steel sheet 201 having seven points coexisting on the circumcircle Y, and the second to seventh-stage silicon steel sheets 207 having three points coexisting on the circumcircle Y, the magnetic field lines are evenly distributed along the circumcircle Y, reducing local hysteresis loss.

[0047] Therefore, this embodiment of the application optimizes the structure of each stage of silicon steel sheet in the single-frame wound core 20, thereby improving the filling coefficient of the single-frame wound core 20. The cross-section of the first stage wound core is designed as a heptagon, with all seven points located on the same circumcircle Y. The cross-sections of the second to seventh stages of the wound core are designed as pentagons, with three points located on the same circumcircle Y. Without increasing the height and volume of the three-dimensional wound core, the filling coefficient is increased from the existing 0.87-0.90 to over 0.98. The cross-sectional area utilization rate of the core column 2011 is increased by more than 15%, and the weight of the three-dimensional wound core can be reduced by about 15%-20%. This saves costs and meets the current requirements for no-load loss, noise, and no-load current balance.

[0048] In practical applications, the cross-sectional structure of silicon steel sheets from grade 201 to grade n is determined by the following calculation formula:

[0049] (n-3)α+4β+θ=120°, the initial included angle of the first-level silicon steel sheet 201 is preset to be α0, α is the central angle between two external points on the circumcircle Y of the second-level silicon steel sheet 202 to the (n-2)th-level silicon steel sheet, β is the central angle between two points on the circumcircle Y of the (n-1)th-level silicon steel sheet, and θ is the central angle between two external points on the circumcircle Y of the nth-level silicon steel sheet.

[0050] In this embodiment of the application, in the above cross-sectional structure calculation formula, when n=7, α0=13.5°, α=13.5°, β=13.5°, and θ=12°. Therefore, calculating the angle according to the formula, we can obtain (4×13.5°)+(4×13.5°)+12°=120°, which meets the design requirement of a semicircle of 180° minus two 30° symmetrical included angles.

[0051] The above formulas facilitate the forming and processing of silicon steel sheets of different grades, making them suitable for forming various grades of silicon steel sheets. For example, when the grade n=6, the values ​​of α, β, and θ are adjusted according to the angle formula (e.g., when n=6, let α=15°, β=15°, θ=15°).

[0052] When the series n=9, adjust the values ​​of α, β, and θ according to the angle formula (e.g., when n=9, set α=11°, β=11°, θ=10°).

[0053] In actual operation, the gap between the first-level silicon steel sheet 201 and the circumscribed circle Y is ≤0.05mm through laser cutting precision control, and the gap between the second-level silicon steel sheet 202 to the seventh-level silicon steel sheet 207 and the circumscribed circle Y is ≤0.1mm through high-precision stamping precision control.

[0054] Therefore, by using precise calculations of the angle formula, it is ensured that the processing parameters of each stage of silicon steel sheet in the single-frame coiled iron core 20 and the filling coefficient after assembly meet the requirement of 0.98 or higher. It also ensures that the common edge line L of adjacent single-frame coiled iron cores 20 completely overlaps, eliminates inter-stage air gaps, and the micro-gap design improves the stacking density of silicon steel sheets at each stage, ensuring the balance of no-load current.

[0055] The multi-level three-dimensional wound iron core structure of this application embodiment also includes polyester glass insulation tape 40, core column binding tape 50 and iron yoke binding tape 30. Among them, after the iron core columns 2011 of three identical single-frame wound iron cores 20 are assembled in pairs, a polyester glass insulation tape 40 with a thickness of 0.25mm is wrapped on the surface of the iron core columns of the two single-frame wound iron cores 20, and then a stainless steel core column binding tape 50 with a thickness of 0.35mm is used to bind it around the outside several times.

[0056] In addition, each level of silicon steel sheet of the single-frame coiled core 20 is wrapped with a 0.45mm thick yoke binding tape 30 (20mm wide epoxy fiberglass tape) for 3 turns on the yoke 2012 (top / bottom). The tension of the yoke binding tape 30 is ≥300N, thereby axially pressing the silicon steel sheets of each level.

[0057] Therefore, by binding the single-frame coiled iron cores 20 assembled in pairs with polyester glass insulating tape 40 and core column binding tape 50, and by binding each stage of silicon steel sheets of each single-frame coiled iron core 20 with yoke binding tape 30, the core column binding tape 50 suppresses radial vibration, the yoke binding tape 30 suppresses axial vibration, and the inter-stage interlocking structure blocks the vibration transmission path, thus ensuring the equilateral triangular layout of the three identical single-frame coiled iron cores 20, the symmetry of the three-phase magnetic circuit, and the complete balance of the no-load current; and by double binding at the yoke part 2012 and the core column 2011, the axial clamping force is increased, and the noise is reduced by about 8dB.

[0058] The splicing interface of the single-frame coiled iron core 20 is provided with a bonding part 208, and the bonding parts 208 of the two spliced ​​single-frame coiled iron cores 20 are bonded together. A composite insulation layer 60 with a thickness of 0.05-0.15mm is placed between the bonding parts 208 of the two. The composite insulation layer 60 can be insulating aramid paper or nano mica tape. The composite insulation layer 60 blocks the eddy current path between phases.

[0059] In this embodiment, the equilateral triangular layout of the three-dimensional wound core assembly 10 is determined and formed by the center line connecting the circumcircle Y of the core columns 2011 of the three single-frame wound cores 20, as shown below. Figure 5 As shown.

[0060] Preferred, such as Figure 6As shown, a first protrusion 2081 is provided on the mating portion 208 of the single-frame coiled iron core 20, and a corresponding first groove 2082 is provided on the mating portion 208 of another single-frame coiled iron core 20. The first protrusion 2081 and the first groove 2082 can be fitted in a rectangular structure or in a dovetail shape. The machining depth of the first groove 2082 is 0.2-0.5mm. When the single-frame coiled iron cores 20 are assembled, the common side lines L of the three single-frame coiled iron cores 20 are aligned. A composite insulation layer 60 is inserted between the mating portions 208 of two single-frame coiled iron cores 20, and then the first protrusion 2081 and the first groove 2082 are engaged. Then, the three single-frame coiled iron cores 20 are covered with polyester glass insulation tape 40 and tied with core column binding tape 50 to fix the equilateral triangular layout of the three single-frame coiled iron cores 20.

[0061] Therefore, by setting a first protrusion 2081 and a first groove 2082 on the mating part 208 of the two assembled single-frame coiled iron cores 20, the magnetic flux density of the iron core column 2011 is evenly distributed by the composite insulation layer 60 and the protrusion and groove, the magnetic circuit length is extended, magnetic saturation is avoided, and the no-load loss is reduced by at least 12%.

[0062] Preferred, such as Figure 7 As shown in the embodiments of this application, the mating surfaces of odd-numbered silicon steel sheets are provided with rectangular, dovetail, or hemispherical second protrusions 209, and the mating surfaces of even-numbered silicon steel sheets are provided with second grooves 2010 that match the second protrusions 209, thereby achieving inter-stage interlocking. Combined with the equilateral triangle layout of the three-dimensional coiled iron core assembly 10 and the inter-stage interlocking of the convex and groove meshing of the single-frame coiled iron core 20, lateral displacement is eliminated, the cumulative air gap between phases is further reduced, and the geometric accuracy of the equilateral triangle layout is improved.

[0063] The above embodiments are merely preferred embodiments of this utility model and should not be construed as limiting the scope of protection of this utility model. Any non-substantial changes and substitutions made by those skilled in the art based on this utility model shall fall within the scope of protection claimed by this utility model.

Claims

1. A multi-stage three-dimensional wound iron core structure, characterized in that, It includes a three-dimensional coiled iron core assembly, which is composed of three identical single-frame coiled iron cores bound together in pairs to form an equilateral triangle layout. The single-frame coiled iron core is composed of n-grade silicon steel sheets fitted from the inside to the outside. The cross-section of the first-stage silicon steel sheet of the single-frame coiled iron core is a heptagon with seven points concentric. The cross-section of the second to nth level silicon steel sheets of the single-frame rolled iron core is a pentagon with three points on a common circle and the other two points on a common side line. This common side line passes through the center of the circumcircle and forms a 30° angle with the horizontal plane.

2. The multi-stage three-dimensional wound core structure of claim 1, wherein The cross-sectional structure of silicon steel sheets from the first grade to the nth grade is determined by the following formula: (n-3)α+4β+θ=120°, where α is the central angle between two points on the circumcircle of the second-level silicon steel sheet to the (n-2)th-level silicon steel sheet, β is the central angle between two points on the circumcircle of the (n-1)th-level silicon steel sheet, θ is the central angle between two points on the circumcircle of the nth-level silicon steel sheet, and the first-level silicon steel sheet has an initial included angle α0, where α0 is equal to α.

3. The multi-stage three-dimensional wound core structure of claim 2, wherein In the calculation formula for the cross-sectional structure of silicon steel sheets from the first grade to the nth grade, when n=7, α0=13.5°, α=13.5°, β=13.5°, and θ=12°.

4. The multi-stage three-dimensional wound core structure of claim 3, wherein The gap between the first-grade silicon steel sheet and the circumscribed circle is ≤0.05mm, and the gap between the second-grade to seventh-grade silicon steel sheets and the circumscribed circle is ≤0.1mm.

5. The multi-stage three-dimensional wound core structure according to any one of claims 1 to 4, wherein It also includes polyester-glass insulation tape and core column binding tape. The core columns of the three single-frame rolled iron cores are assembled in pairs and then bound together by the polyester-glass insulation tape. Several core column binding tapes are also bound to the outside of the polyester-glass insulation tape.

6. The multi-stage three-dimensional wound core structure according to any one of claims 1 to 4, wherein It also includes iron yoke binding straps, and each level of silicon steel sheet of the single-frame coiled iron core is connected to each other by several of the iron yoke binding straps.

7. The multi-stage three-dimensional wound core structure according to any one of claims 1 to 4, wherein The single-frame coiled iron core has a bonding part, the bonding parts of the two assembled single-frame coiled iron cores are bonded together, and a composite insulation layer with a thickness of 0.05-0.15mm is placed between the bonding parts of the two.

8. The multi-stage three-dimensional wound core structure of claim 7, wherein The mating part of the single-frame coiled iron core is provided with a first protrusion, and the mating part of the other single-frame coiled iron core that cooperates with it is provided with a corresponding first groove.

9. The multi-stage three-dimensional wound core structure as described in any one of claims 1-4, characterized in that, The equilateral triangular layout of the three-dimensional coiled iron core assembly is formed by connecting the centers of the circumcircles of the iron core columns of each single-frame coiled iron core.

10. The multi-stage three-dimensional wound core structure according to any one of claims 1 to 4, wherein The mating surface of the odd-numbered silicon steel sheets is provided with a second protrusion, and the mating surface of the even-numbered silicon steel sheets is provided with a second groove that matches the second protrusion.

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