transformer

Abstract

To reduce noise due to magnetostriction at a laminated iron core.SOLUTION: A transformer (1) comprises: an iron core (10) formed by laminating a plurality of magnetic steel sheets and having a leg portion (11); a first patch (41) and a second patch (42) that are provided along both sides in a lamination direction, of each magnetic steel sheet in the leg portion; and a first vibration suppression plate (43) and a second vibration suppression plate (44) that connect the first patch and the second patch to each other. Each of the first vibration suppression plate and the second vibration suppression plate, comprises: first beam portions (43a and 44a) that connect both of one end portions in a Z direction, of each of the first and second patches; second beam portions (43b and 44b) that connect both the other end portions in the Z direction, of each of the first and second patches; first brace portions (43c and 44c) that connect the one end portion in the Z direction, of the first patch and the other end portion in the Z direction, of the second patch; and second brace portions (43d and 44d) that connect the other end portion in the Z direction, of the first patch and the one end portion in the Z direction, of the second patch.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a transformer having an iron core formed by laminating electromagnetic steel sheets. [Background technology]

[0002] A transformer is a device that converts the voltage of AC power using electromagnetic induction, and is configured with an iron core that forms a magnetic circuit and a winding that forms an electric circuit.

[0003] In transformers, the application of an alternating magnetic field can cause magnetostrictive deformation in the iron core, which can cause the iron core to vibrate the air and generate noise. A known configuration for reducing such noise is disclosed in Patent Document 1. In Patent Document 1, the entire iron core is covered with sound-absorbing material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-124044 Summary of the Invention [Problem to be solved by the invention]

[0005] Laminated cores made of multiple stacked electromagnetic steel sheets are widely used in transformers. The inventors noticed that when the above-mentioned magnetostrictive deformation occurs in the legs of such laminated cores, it causes bending mode deformation in the lamination direction, generating noise. Furthermore, in order to suppress the generation of such noise, the inventors investigated a configuration that corresponds to the bending mode of the legs, as a technology different from that of Patent Document 1, and invented a technology that can reduce noise.

[0006] The present invention has been made in view of the above points, and one of its objects is to provide a transformer that can reduce noise in a laminated core caused by magnetostriction. [Means for solving the problem]

[0007] A transformer according to one aspect of the present invention is a transformer comprising: an iron core formed by stacking a plurality of electromagnetic steel sheets and having at least one leg; a first backing plate and a second backing plate provided along both surfaces of the leg in the stacking direction of the electromagnetic steel sheets; and a first vibration suppression plate and a second vibration suppression plate connecting the first backing plate and the second backing plate, wherein the first backing plate and the second backing plate extend parallel to the extension direction of the leg, and the first vibration suppression plate and the second vibration suppression plate are: The support plate is characterized by comprising a first beam portion connecting one end portion in the extension direction of each of the first support plate and the second support plate, a second beam portion connecting the other end portion in the extension direction of each of the first support plate and the second support plate, a first brace portion connecting one end portion in the extension direction of the first support plate and the other end portion in the extension direction of the second support plate, and a second brace portion connecting the other end portion in the extension direction of the first support plate and one end portion in the extension direction of the second support plate. [Effects of the Invention]

[0008] According to the present invention, the legs of the core are surrounded by plate material by the backing plates and vibration suppression plates. This increases the bending rigidity of the core as a unit against excitation vibration and reduces noise caused by leg vibration. Furthermore, the bracing structure of each vibration suppression plate effectively suppresses leg vibration in the lamination direction of the electromagnetic steel sheets, further reducing noise. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic perspective view of a transformer according to an embodiment, with a portion of the configuration thereof omitted; [Figure 2] 1 is a schematic perspective view of a vibration suppression structure according to an embodiment; [Figure 3] FIG. 1 is an explanatory diagram of measurement points in analysis. [Figure 4] 10 is a graph showing a result of a frequency response analysis according to an embodiment. [Figure 5]10 is a graph showing a frequency response analysis result of a comparative example. [Figure 6] 10 is a graph showing a comparison result of acceleration response between the embodiment and the comparative example. [Figure 7] FIG. 2 is a perspective view similar to FIG. 1 of a transformer according to a first modified example. [Figure 8] FIG. 10 is a perspective view similar to FIG. 1 of a transformer according to a second modification. DETAILED DESCRIPTION OF THE INVENTION

[0010] A transformer according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The following describes the case where the transformer according to the present invention is applied to a dry-type transformer (e.g., an H-type dry-type transformer), a gas-insulated transformer, and an oil-immersed transformer.

[0011] The present invention is not limited to the following embodiments, and can be modified as appropriate within the scope of the present invention. For ease of explanation, some components may be omitted in the following figures. The following explanation will be based on the X, Y, and Z directions indicated by arrows in each figure. In the following embodiments, the Z direction is the height direction (vertical, up-down direction), the Y direction is the stacking direction of the electromagnetic steel sheets that make up the laminated core, and the X direction is the direction perpendicular to the Z and Y directions. However, these directions may be changed as long as the same functions as those of the embodiments can be achieved.

[0012] Fig. 1 is a schematic perspective view of a transformer according to an embodiment, with some of the configuration omitted. The transformer 1 shown in Fig. 1 is configured to include an iron core 10 that forms a magnetic circuit, windings (coils) that form an electric circuit (not shown), and a frame portion 30 that supports the iron core 10.

[0013] Core 10 is a laminated core formed by stacking multiple electromagnetic steel sheets in the Y direction. Examples of electromagnetic steel sheets include non-oriented silicon steel sheets, oriented silicon steel sheets, and 6.5% silicon steel sheets. Core 10 includes multiple legs 11 and upper yoke portions 12 and lower yoke portions 13 joined above and below legs 11. In this embodiment, transformer 1 has a three-phase, three-leg structure in which there are three legs 11 and windings are arranged around each leg 11, but the number of legs 11 may be at least one.

[0014] The frame section 30 includes an upper frame 31 provided at the upper end of the iron core 10 and a lower frame 32 provided at the lower end of the iron core 10 .

[0015] The upper frame 31 and the lower frame 32 are provided on both sides of the iron core 10 in the Y direction, and the upper region of the iron core 10 is supported by being sandwiched between the pair of upper frames 31, and the lower region of the iron core 10 is supported by being sandwiched between the pair of lower frames 32. Each of the frames 31, 32 is made of a metal structure such as a steel material or a sheet metal material that has a U-shaped cross section and extends in the longitudinal direction.

[0016] A pair of support frames 34 are provided below the lower frame 32, aligned in the X direction. A plate-shaped upper spacer 35 and a lower spacer 36, which is wider than the support frame 34, are sandwiched between the support frame 34 and the lower frame 32. The support frame 34 and the lower spacer 36 are made of steel or sheet metal material whose cross section is mainly formed into a constant channel shape (U-shape) and extends in the longitudinal direction (Y direction). The support frame 34 is used for installing and fixing the transformer 1.

[0017] The transformer 1 is provided with vibration suppression structures 40 at positions surrounding each leg 11 from both sides in the X direction and both sides in the Y direction. The vibration suppression structures 40 are provided with the same structure for each of the three legs 11. In other words, the transformer 1 of this embodiment has three vibration suppression structures 40 with the same structure.

[0018] Fig. 2 is a schematic perspective view of a vibration suppression structure according to an embodiment. As shown in Fig. 2, a vibration suppression structure 40 includes a first backing plate 41 and a second backing plate 42 provided along both surfaces of the leg 11 in the Y direction, and a first vibration suppression plate 43 and a second vibration suppression plate 44 provided on both sides of the leg 11 in the X direction. Each of the backing plates 41, 42 and each of the vibration suppression plates 43, 44 is made of a non-magnetic material and is made of a rigid body such as a metal plate.

[0019] Here, the first backing plate 41 is provided along the +Y side surface of the leg 11, and the second backing plate 42 is provided along the -Y side surface of the leg 11. The backing plates 41, 42 are provided in the same shape and are arranged parallel to the ZX plane.

[0020] Each backing plate 41, 42 has a rectangular main surface 41a, 42a that extends parallel to the extension direction (Z direction) of the leg 11 and has a width in the X direction that is smaller than the width of the leg 11 in the X direction. Each backing plate 41, 42 also has protrusions 41b, 42b that are formed on both sides in the X direction in both Z direction regions of the main surface 41a, 42a. The X direction width of the portions of each backing plate 41, 42 where the protrusions 41b, 42b are formed is larger than the width of the leg 11 in the X direction. Therefore, the protrusions 41b, 42b are arranged to protrude from the leg 11 on both sides in the X direction.

[0021] In the vibration suppression structure 40 of this embodiment, a first vibration suppression plate 43 is provided along the +X side surface of the leg 11, and a second vibration suppression plate 44 is provided along the -X side surface of the leg 11. The vibration suppression plates 43, 44 are provided in the same shape and arranged parallel to the YZ plane. A gap is formed between the leg 11 and each of the vibration suppression plates 43, 44, and they are arranged apart so that they do not come into contact with each other even if deformation of the leg 11 occurs, as described below.

[0022] Each vibration suppression plate 43, 44 includes a first beam portion 43a, 44a, a second beam portion 43b, 44b, a first brace portion 43c, 44c, and a second brace portion 43d, 44d, respectively.

[0023] The first beam portions 43a and 44a connect the upper ends (one end in the Z direction) of the first backing plate 41 and the second backing plate 42. More specifically, the first beam portions 43a and 44a connect the protruding portions 41b and 42b on the +Z side of the first backing plate 41 and the second backing plate 42.

[0024] The second beam portions 43b, 44b connect the lower ends (other ends in the Z direction) of the first backing plate 41 and the second backing plate 42. More specifically, the second beam portions 43b, 44b connect the protruding portions 41b, 42b on the -Z side of the first backing plate 41 and the second backing plate 42.

[0025] The first brace portions 43c, 44c connect the upper end of the first backing plate 41 and the lower end of the second backing plate 42. More specifically, the first brace portions 43c, 44c connect the protruding portion 41b on the +Z side of the first backing plate 41 and the protruding portion 42b on the -Z side of the second backing plate 42.

[0026] The second brace portions 43d, 44d connect the lower end of the first backing plate 41 and the upper end of the second backing plate 42. More specifically, the second brace portions 43d, 44d connect the protruding portion 41b on the -Z side of the first backing plate 41 and the protruding portion 42b on the +Z side of the second backing plate 42.

[0027] It is preferable to connect the vibration suppression plates 43, 44 to the protrusions 42b of the backing plates 41, 42 by welding, but various configurations other than welding, such as adhesive bonding, can be used as long as they are secured to each other.

[0028] 1 and 2 show a configuration in which the vibration suppression plates 43, 44 are integrally formed by cutting out a single plate, but this is not limited to this. In each vibration suppression plate 43, 44, the first beam portions 43a, 44a, the second beam portions 43b, 44b, the first brace portions 43c, 44c, and the second brace portions 43d, 44d may be formed separately. When formed as separate bodies in this way, the ends of each portion may be overlapped, or the first brace portions 43c, 44c and the second brace portions 43d, 44d may be overlapped at their intersections.

[0029] Next, an analysis performed to confirm the vibration suppression effect of the vibration suppression structure 40 on the leg portion 11 will be described below with reference to FIGS.

[0030] It is generally known that in transformers having legs (iron cores) as described above, the legs undergo magnetostrictive deformation when an alternating magnetic field is applied, and the frequency of the electromagnetic noise generated by such magnetostrictive deformation is 2n times (n is a natural number) the excitation frequency.

[0031] Therefore, prior to the above analysis, a model consisting of only the above-mentioned iron core 10 and frame portion 30 was created. Then, tests were conducted on this model under two different conditions: one condition in which electricity was passed through at an excitation frequency of 50 Hz, and one condition in which an excitation force was applied to the base of the iron core 10. In this test, under the above two conditions, the vibration modes of the legs 11 were measured at frequencies near 100 Hz, 200 Hz, and 300 Hz, which are 2n times the excitation frequency, and the vibration modes of the legs 11 were compared.

[0032] As a result of the comparison, it was found that the vibration modes of legs 11 under the above two conditions were similar at frequencies near 100 Hz, 200 Hz, and 300 Hz. In other words, it was found that legs 11 of iron core 10, which generates electromagnetic noise, vibrates mainly in a bending mode similar to that when an excitation force is applied to the base of iron core 10. Therefore, this analysis was a frequency response analysis when an excitation force is applied to the base of iron core 10.

[0033] In order to confirm the vibration suppression effect of the embodiment, an analytical model was created that had the above-described iron core 10, frame portion 30, and vibration suppression structure 40. In addition, as a comparative example, an analytical model was also created in which the vibration suppression plates 43 and 44 were omitted from the analytical model of the above-described embodiment.

[0034] A frequency response analysis was performed on the analytical models of the embodiment and the comparative example. The conditions for this frequency response analysis were as follows: 16 acceleration measurement points were set at equal intervals in the Z direction on the +X side surface of the +X side leg 11, as shown by the dashed circle in Fig. 3. Fig. 3 is an explanatory diagram of the measurement points used in the analysis.

[0035] In the frequency response analysis, a vibration force of 10 G was applied in the Y direction to the lower frame 32, which is the base of the iron core 10. In addition, the support frame 34 supporting the lower frame 32 and the like were constrained.

[0036] Under the above conditions, a frequency response analysis was performed on the analytical models of the embodiment and the comparative example from the measurement results at each measurement point in FIG. 3, and the results shown in the graphs of FIG. 4 and FIG. 5 were obtained. FIG. 4 is a graph showing the frequency response analysis results of the embodiment. FIG. 5 is a graph showing the frequency response analysis results of the comparative example. The graphs of FIG. 4 and FIG. 5 have frequency [Hz] on the horizontal axis and acceleration [mm / s 2 ] and plots the measurement results at 16 measurement points.

[0037] As shown in the graph of FIG. 4, in the embodiment, there were 11 vibration modes (1) to (11) in the frequency range of 0 to 500 Hz. As shown in the graph of FIG. 5, in the comparative example, there were 18 vibration modes (1) to (18) in the frequency range of 0 to 500 Hz. Therefore, the embodiment was able to reduce the number of vibration modes compared to the comparative example. This reduction in the number of vibration modes is thought to be due to the fact that the first vibration suppression plate 43 and the second vibration suppression plate 44 of the vibration suppression structure 40 improve the bending rigidity of the leg 11 and the vibration suppression structure 40 when viewed as a single unit, thereby suppressing bending mode vibrations of the leg 11. By reducing the number of vibration modes, it is possible to reduce the possibility of the leg 11 resonating even when an alternating magnetic field is applied, which can contribute to noise suppression.

[0038] Fig. 6 is a graph showing the results of comparing the acceleration response between the embodiment and the comparative example. The horizontal axis of the graph in Fig. 6 represents the measurement points of acceleration, which are numbered consecutively from 1 to 16 from the top to the bottom (-Z direction) of the leg 11. The vertical axis of the graph in Fig. 6 represents the OA value [mm / s 2 In the graph of Fig. 6, the OA values ​​of the comparative example are indicated by black dots, and the OA values ​​of the embodiment are indicated by white dots.

[0039] 6, the OA value was smaller at all measurement points in the embodiment than in the comparative example. As a result, the bending rigidity of the first vibration suppression plate 43 and the second vibration suppression plate 44 of the vibration suppression structure 40 is improved, which suppresses bending mode vibration of the leg 11 and reduces noise.

[0040] According to the above embodiment, the backing plates 41, 42 and the vibration suppression plates 43, 44 of the vibration suppression structure 40 can surround the leg 11 on all four sides (X direction and Y direction) with rigid bodies. This increases the bending rigidity of the leg 11 and the vibration suppression structure 40 as a unit against excitation vibration, and reduces noise caused by vibration of the leg 11. Furthermore, because the vibration suppression plates 43, 44 have a diagonal brace structure, they can effectively suppress vibration in the stacking direction (Y direction) of the electromagnetic steel sheets in the leg 11, thereby further reducing noise.

[0041] The embodiments of the present invention are not limited to the above-described embodiments, and may be variously modified, substituted, or altered within the scope of the spirit of the technical idea of ​​the present invention. Furthermore, if the technical idea of ​​the present invention can be realized in a different way due to technological advances or other derived technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea of ​​the present invention.

[0042] For example, the vibration suppression structure 40 is not limited to the configuration of the above embodiment, and may be modified to the configurations shown in Figures 7 and 8. Figure 7 is a perspective view similar to Figure 1 of a transformer according to a first modified example. Figure 8 is a perspective view similar to Figure 1 of a transformer according to a second modified example.

[0043] 7, compared to the above embodiment, each vibration suppression plate 43, 44 of the vibration suppression structure 40 further includes a third beam portion 44e (the third beam portion of the first vibration suppression plate 43 is not shown). Each third beam portion 44e connects the first backing plate 41 and the second backing plate 42 at their respective intermediate portions in the Z direction, and is provided so as to pass through the intersection of the first brace portion 44c and the second brace portion 44d. In the first modification, the first backing plate 41 and the second backing plate 42 also include protrusions 41b, 42b at their intermediate portions in the Z direction, and the protrusions 41b, 42b are connected to each other by the third beam portion 44e.

[0044] In the first modified example, the provision of the third beam portion 44e is expected to further reduce the number of vibration modes and suppress noise. Furthermore, the first vibration suppression plate 43 and the second vibration suppression plate 44, including the third beam portion 44e, improve bending rigidity, thereby suppressing bending mode vibrations of the leg portion 11 and reducing noise.

[0045] 8 differs from the above embodiment in that each backing plate 41, 42 of vibration suppression structure 40 further includes a rib 41c (the rib of second backing plate 42 is not shown). Each rib 41c protrudes from the center of main surface portions 41a, 42a in the X direction to the side opposite leg portion 11, and extends parallel to the extension direction (Z direction) of leg portion 11 and main surface portions 41a, 42a.

[0046] In the second modified example, the formation of the rib 41c is expected to further reduce the number of vibration modes and suppress noise. Furthermore, the first backing plate 41 and the second backing plate 42, which include the rib 41c, improve bending rigidity, thereby suppressing bending mode vibrations of the leg 11 and reducing noise. Note that the rib 41c may be formed on each of the backing plates 41, 42 of the first modified example.

[0047] In addition, in the above embodiment, the backing plates 41, 42 are provided in contact with both surfaces of the leg 11 in the Y direction, but this is not limiting. For example, a vibration-damping material made of an elastically deformable material such as rubber may be interposed between both surfaces of the leg 11 in the Y direction and the backing plates 41, 42. With this configuration, the vibration of the leg 11 can be absorbed by the vibration-damping material, thereby reducing noise.

[0048] Furthermore, vibration-proofing materials similar to those described above may be sandwiched between the legs 11 and the vibration suppression plates 43, 44 to prevent noise caused by vibration of the legs 11.

[0049] Furthermore, in the above embodiment, the present invention has been described as being applied to a transformer, but it can also be applied to other power static devices and power conversion devices as long as the above-mentioned effects can be obtained.

[0050] Furthermore, the contents illustrated in the above embodiment are merely shown schematically for the purpose of explanation, and the structure of the frame portion 30 may be changed as long as the above-mentioned effects can be achieved. [Explanation of symbols]

[0051] 1: Transformer 10: Iron core 11: Legs 41: First backing plate 41c: Rib 42: Second backing plate 43: 1st vibration suppression plate 43a: First beam section 43b: Second beam section 43c: First brace section 43d: Second brace section 44:Second vibration suppression plate 44a: First beam section 44b: Second beam section 44c: First brace section 44d: Second brace section 44e: Third beam section

Claims

1. an iron core formed by laminating a plurality of electromagnetic steel sheets and having at least one leg; a first backing plate and a second backing plate provided along both surfaces of the leg portion in the lamination direction of the electromagnetic steel sheets; A transformer including a first vibration suppression plate and a second vibration suppression plate connecting the first backing plate and the second backing plate, The first backing plate and the second backing plate extend parallel to the extending direction of the leg portion, The first vibration suppression plate and the second vibration suppression plate each include a first beam portion connecting one end portion of the first backing plate and one end portion of the second backing plate in the extension direction to each other; a second beam portion connecting the other end portions of the first backing plate and the second backing plate in the extension direction to each other; a first brace portion connecting one end of the first backing plate in the extension direction and the other end of the second backing plate in the extension direction; a second brace portion connecting the other end of the first backing plate in the extension direction to the one end of the second backing plate in the extension direction.

2. 2. The transformer according to claim 1, wherein the first vibration suppression plate and the second vibration suppression plate each include a third beam portion that passes through an intersection of the first brace portion and the second brace portion.

3. 3. The transformer according to claim 1, wherein the first backing plate and the second backing plate are formed with ribs extending parallel to the extending direction.

4. 4. The transformer according to claim 1, wherein vibration-proofing materials are sandwiched between the legs and the first vibration suppression plate and between the legs and the second vibration suppression plate.

5. 4. The transformer according to claim 1, wherein gaps are formed between the legs and the first vibration suppression plate and between the legs and the second vibration suppression plate.

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