A magnetic shield assembly for a reactor body and a reactor

Abstract

The present application belongs to the technical field of electric reactors, and particularly relates to a reactor body magnetic shielding assembly for electric reactors and an electric reactor. The reactor body magnetic shielding assembly is a silicon steel sheet group stacked radially along the iron core column. The silicon steel sheet group sequentially comprises a long sheet area, a transition area, a variable level area, a short sheet area, a variable level area, a transition area and a long sheet area along the stacking direction. The variable level area is stacked by several variable level silicon steel sheets with different lengths. The variable level silicon steel sheets are stacked in a circular arc surface near the variable level area on the side of the iron core column. The length difference between the adjacent two variable level silicon steel sheets is less than 0.1 mm. The technical scheme provided by the present application has the following advantages compared with the prior art: the side of the magnetic shielding assembly near the iron core column is a rounded surface without sharp edges and corners, which improves the electric field and the magnetic field, and has better reliability; the fixing strength of the silicon steel sheet is enhanced by setting the short clamping piece, the area of the reactor body magnetic shielding for collecting magnetic flux is increased, and therefore the shielding and magnetic field uniformity effect is better.

Description

Technical Field

[0001] This invention belongs to the field of reactor technology, specifically relating to a reactor body magnetic shielding assembly and a reactor. Background Technology

[0002] In iron-core reactors, magnetic shielding components are typically installed to provide a low-resistivity magnetic circuit for leakage flux, reducing the possibility of localized overheating caused by leakage flux, improving product reliability, and reducing losses. In existing technology, both the horizontal and vertical axes are the center lines of the reactor body. The magnetic shielding components are made of stacked silicon steel sheets. Clamps made of non-magnetic steel plates are inserted into the inner and outer edges of the longest silicon steel sheets at both ends, and fixed by fixing plates. To avoid the location of the core column in the iron core, the silicon steel sheets are divided into several lengths and stacked accordingly. After stacking, they form a stepped shape facing the core column. The longest step is usually called the first length step, and the shortest step is called the second length step. Except for the first and second length steps, the vertices of other steps are distributed on a circle with a diameter slightly larger than the diameter of the core column, i.e., the circle circumscribed by the vertices of the steps.

[0003] The existing technology has many shortcomings: First, because silicon steel sheets of different lengths are stacked in steps near the inner edge of the core column, the area of ​​the magnetic shield receiving leakage flux is lost, resulting in low magnetic shielding efficiency. Second, only the longest silicon steel sheet has a step length suitable for setting up a non-magnetic steel plate clamp and thus rounding it off. The shortest silicon steel sheet is stacked on its own to form a round shape, while the inner edge of the step on the side of the other silicon steel sheets is directly exposed and cannot be rounded off. As a result, the charge and magnetic lines are relatively concentrated, the insulation effect is poor, and electromagnetic noise is difficult to control. Summary of the Invention

[0004] This invention overcomes the problem in the prior art that the stacking of silicon steel sheets cannot achieve roundness, resulting in poor magnetic shielding and insulation effects.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: the magnetic shielding assembly of the core is a group of silicon steel sheets stacked radially along the iron core column. The silicon steel sheet group includes, in sequence along the stacking thickness direction, a long sheet region, a transition region, a variable stage region, a short sheet region, a variable stage region, a transition region, and a long sheet region. The long sheet region is composed of several first silicon steel sheets of equal length. The transition region is composed of several second silicon steel sheets of equal length. The short sheet region is composed of several third silicon steel sheets of equal length. The length of the first silicon steel sheets is greater than the length of the second silicon steel sheets, and the length of the second silicon steel sheets is greater than the length of the third silicon steel sheets. The variable stage region is composed of several variable stage silicon steel sheets of unequal length. The variable stage silicon steel sheets of unequal length are stacked in an arc shape on the side of the variable stage region near the iron core column, and the length difference between two adjacent variable stage silicon steel sheets is less than 0.1 mm.

[0006] Optionally, it also includes a short clamp disposed in the transition area, which cooperates with the clamp to fix the silicon steel sheet. One end of the short clamp that connects with the silicon steel sheet in the transition area is concave and matches the shape of the second silicon steel sheet. The other end of the short clamp is an arc.

[0007] Unlike existing clamps, the concave surface of the short clamp sits on the end of the second silicon steel sheet, short-circuiting the mounted silicon steel sheet. Since all silicon steel sheets are already welded to the non-magnetic steel plate fixing component, the mounted silicon steel sheet eliminates the short-circuit ring, reducing losses. Furthermore, due to the electromagnetic attraction between the magnetic shield and the core column, this force changes periodically. In existing technologies, there are no clamps at the step; if the silicon steel sheet is not fully impregnated and adhered, or if vibration causes it to separate, the inner edge of the silicon steel sheet will swing towards the core column, generating noise, or even breaking, creating a floating potential or causing insulation breakdown, leading to accidents. This invention, by setting a transition zone, can better fix the silicon steel sheets in the variable-stage area.

[0008] Optionally, the short clamps located on both sides of the long area are secured to the clamps by at least one cable tie.

[0009] Optionally, the stack thickness H2 of the transition region is obtained through the following steps:

[0010] S1: Calculate the distance F between the short clamp and the variable-level region using Formula 1.1:

[0011]

[0012] Where R is the radius of the core column, Q is the shortest distance between the magnetic shielding assembly of the device body and the core column, W is the distance between the arc surface of the variable stage region and the surface of the core column, L is the distance of the first silicon steel sheet from the center line in the length direction of the magnetic shielding assembly of the device body, and E is the height difference between the long sheet region and the transition region. In this step, E is obtained by formula (1.2).

[0013] E = M + G + P (1.2),

[0014] Where E is the height difference between the long area and the transition area, M is the radius of the arc at the end of the short clamp, G is the width of the binding strap, and P is a fixed value, ranging from 5 to 10 mm.

[0015] S2: If F ≥ 0 is calculated in S1, then only one strap needs to be set, and the thickness H2 of the transition region can be obtained through formula 1.3:

[0016] H2=F+δ (1.3);

[0017] Where δ is the thickness of the short clamp;

[0018] S3: If F < 0 in S1, then n straps need to be set, and the value of E needs to be recalculated using formula 1.4:

[0019] E = M + nG + (n-1)T + P (1.4)

[0020] Where T is the gap between two adjacent bindings, and n≥2 is the number of binding straps;

[0021] Then, F is calculated using Formula 1.1, and the stack thickness H2 of the transition region is obtained using Formula 1.3.

[0022] Optionally, the Q value is 17mm, the W value is 20mm, and the L value is 5mm; when the capacity is small, P takes a smaller value, M = B, G = 50mm; where B is the width of the silicon steel sheet; when the capacity is large, P takes a larger value, M = 0.7B, G = 40mm or 50mm.

[0023] Optionally, the concave end of the short clamp is insulated from the second silicon steel sheet by Normac paper.

[0024] Optionally, the following parameters are given according to design requirements: core column diameter D, silicon steel sheet stack thickness A, silicon steel sheet width B, and clamp thickness δ;

[0025] The stacking thickness H1 of the long strip region is calculated using formula 2.1:

[0026] H1=A-(D+2Q+2δ) / 2 (2.1)

[0027] Where Q is the shortest distance between the magnetic shielding assembly of the device body and the iron core column;

[0028] The stack thickness C of the short slice region is obtained by formula 2.2:

[0029]

[0030] Where R is the radius of the core column, i.e., D / 2, and W is the distance between the arc surface of the variable stage region and the surface of the core column.

[0031] Optionally, all the silicon steel sheets in the silicon steel sheet assembly and the clamps are stacked in a mold and fixed by epoxy resin bonding.

[0032] The present invention also provides a reactor, the reactor comprising the above-mentioned reactor body magnetic shielding assembly.

[0033] The technical solution provided by this invention has the following advantages compared with the prior art: the side of the magnetic shielding component near the iron core column is a rounded surface without sharp edges and corners, which improves the electric field and magnetic field and makes it more reliable; while keeping other geometric dimensions unchanged, the area of ​​magnetic shielding of the device body that gathers magnetic flux is increased, so the shielding and magnetization effects are better. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a specific embodiment of the reactor body magnetic shielding assembly described in this invention;

[0035] Figure 2 This is a front view of a specific embodiment of the short clamp described in this invention;

[0036] Figure 3 yes Figure 2 The right view.

[0037] As shown in the figure:

[0038] 1-Core column, 2-Clamping piece, 3-Fixing plate, 4-Silicon steel sheet assembly, 41-Long sheet area, 42-Transition area, 43-Variable grade area, 44-Short sheet area, 5-Short clamping piece, 6-Binding strap. Detailed Implementation

[0039] For ease of understanding, the reactor body magnetic shielding assembly is described below with reference to embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0040] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation and positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] like Figure 1 As shown, the reactor includes: a core column 1, a magnetic shielding assembly symmetrically arranged on both sides of the core column 1, clamps 2 arranged at both ends of the magnetic shielding assembly, and a fixing plate 3 for fixing the clamps 2.

[0043] See also Figure 1 The magnetic shielding assembly of the device body is a silicon steel sheet group 4 stacked radially along the iron core column 1. The silicon steel sheet group 4 includes, in sequence along the stacking thickness direction, a long sheet region 41, a transition region 42, a variable stage region 43, a short sheet region 44, a variable stage region 43, a transition region 42, and a long sheet region 41. The long sheet region 41 is formed by stacking a number of first silicon steel sheets of equal length. The transition region 42 is formed by stacking a number of second silicon steel sheets of equal length. The short sheet region 44 is formed by stacking a number of third silicon steel sheets of equal length.

[0044] The length of the first silicon steel sheet is greater than the length of the second silicon steel sheet, and the length of the second silicon steel sheet is greater than the length of the third silicon steel sheet; the variable grade region 43 is composed of several variable grade silicon steel sheets stacked together, and the length of the variable grade silicon steel sheets increases progressively from the length of the second silicon steel sheet to the length of the third silicon steel sheet. (Continue to see...) Figure 1 The variable grade region 43 has an arc surface on the side near the core column, and the length difference between two adjacent variable grade silicon steel sheets is less than 0.1 mm, generally around 0.05 mm.

[0045] See also Figure 1 Within the transition region 42, a short clamp 5, which cooperates with the clamp 2 to fix the silicon steel sheet, such as... Figure 2-3 As shown, the short clamp 5 has a raised arc at the upper end and a concave arc at the lower end. The concave arc connects with the silicon steel sheet in the transition area 42 and matches the shape of the second silicon steel sheet. Nomike paper insulation is placed between the concave arc of the short clamp 5 and the silicon steel sheet to eliminate closed loops and reduce losses.

[0046] See also Figure 1 The short clamps 5 located on both sides of the long area 41 are fixed to the clamps 2 by the binding straps 6. In addition, if the far center line end extends a long distance, binding straps can also be set on the left and right clamps 2 for binding.

[0047] The specific process is as follows:

[0048] First, based on comprehensive factors such as product capacity, voltage level, core size, coil size, leakage flux, and leakage flux distribution, the electromagnetic scheme is determined. The design scheme specifies the dimensions of the magnetic shielding within the device body as follows:

[0049] Data such as core column diameter D, core column radius R, silicon steel sheet stack thickness A, silicon steel sheet width (also clamp width) B, clamp thickness δ, and magnetic shielding length of the device body.

[0050] Furthermore, fixed dimensions reflecting the relative positions of the magnetic shielding of the reactor body with the core pillars, yoke, and core clamps are provided:

[0051] The distance between a pair of magnetic shields in the device body is 10mm. The distance L from the center line of the first silicon steel sheet in the length direction of the magnetic shielding assembly in the device body is 5mm. The radius of the arc of the silicon steel sheet of the magnetic shielding in the device body is larger than the radius of the iron core column, that is, the distance W between the arc surface of the arc area of ​​the arc area and the surface of the iron core column is 20. The distance from the end of the short plate area to the outer circumference of the iron core column and the distance from the center line of the inner edge of the shorter clamp are both set to the shortest distance Q between the magnetic shielding assembly in the device body and the iron core column, which is 17mm.

[0052] Then, the stacking thickness of each region is calculated. The lengths of the first silicon steel sheet in the long region and the third silicon steel sheet in the short region can be easily calculated based on known data such as the length of the magnetic shielding of the core body, the distance between a pair of magnetic shieldings of the core body, and the distance from the end of the short region to the outer circumference of the core column. The length of the variable-grade silicon steel sheet in the variable-grade region changes continuously, with the length difference between adjacent sheets being minimal, and the length difference between adjacent sheets is not equal at different positions. This length can be calculated or controlled by the computer of the automatic stepping shearing line, which will not be elaborated here.

[0053] The following section mainly elaborates on the stacking thickness of silicon steel sheets in each region, and the calculation method for the length of the second silicon steel sheet in the transition region. See also... Figure 1 :

[0054] The stacking thickness H1 of the long strip region can be calculated using formula 2.1:

[0055] H1=A-(D+2Q+2δ) / 2=A-(D+34+2δ) / 2 (2.1);

[0056] The stack thickness C of the short slice region can be obtained by formula 2.2:

[0057]

[0058] The thickness H2 of the transition region needs to be obtained through the following steps: The height difference E between the long plate region and the transition region and the distance F between the short clamp and the variable stage region need to be calculated. To maximize leakage flux, it is desirable that E and F be as small as possible. However, the short clamp 5 must be secured with binding strap 6. E must meet certain requirements, which are related to the radius M of the arc at both ends of the silicon steel sheet and the width G of the binding strap. The specific calculation is as follows:

[0059] S1: Calculate the distance F between the short clamp and the variable-level region using Formula 1.1:

[0060]

[0061] E is obtained through formula (1.2).

[0062] E = M + G + P (1.2);

[0063] Where M is the radius of the arc at the short clamp end, G is the width of the binding strap, and P is a fixed value, ranging from 5 to 10 mm.

[0064] When the capacity is small, P takes a smaller value, M = B, G = 50mm;

[0065] When the capacity is large, P takes a larger value, M = 0.7B, G = 40mm or 50mm.

[0066] S2: If F≥0 is calculated in S1, then only one strap needs to be set, and the transition can be obtained through formula 1.3.

[0067] The stacking thickness H2 of the region:

[0068] H2=F+δ (1.3);

[0069] Where δ is the thickness of the short clamp;

[0070] S3: When the core diameter D is very large, a negative value F may be calculated in S1, that is, F < 0. In this case, E should be increased. Assume two binding straps with a gap of T between them, and recalculate the value of E using formula 1.4:

[0071] E=M+nG+(n-1)T+P=M+2G+T (1.4)

[0072] Where T is the gap between two adjacent bindings, and n = 2;

[0073] Then, F is calculated using Formula 1.1, and the stack thickness H2 of the transition region is obtained using Formula 1.3.

[0074] Finally, the stacking thickness H2 of the transition region can be obtained through the F value, and the length of the second silicon steel sheet can be obtained through the E value and the magnetic shielding length of the device body.

[0075] The stack thickness H3 of the variable-level region can be obtained by formula 3.1:

[0076] H3=(AC-2H1-2H2) / 2 (3.1)

[0077] Finally, after determining all the dimensional parameters, epoxy resin is injected when stacking silicon steel sheets, clamps, and short clamps in the mold, or epoxy resin is applied in advance or applied and infiltrated in a loose state. Then, the remaining silicon steel sheets are coated with epoxy resin and inserted between the sheets and squeezed to the required value. Next, NOMEX paper is glued in, cured and shaped, and then welded to the fixing plate 3. The four sides of the contact surface between the fixing plate 3 and the silicon steel sheets and clamps are weld lines. After cleaning, the binding straps 6 are used for binding and adhesive bonding.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A magnetic shield assembly for a core of a reactor, the reactor comprising: The core column, the body magnetic shielding assembly symmetrically arranged on both sides of the core column, the clamping piece arranged at both ends of the body magnetic shielding assembly, and the fixing plate for fixing the clamping piece; characterized in that the body magnetic shielding assembly is a silicon steel sheet group stacked along the radial direction of the core column, the silicon steel sheet group sequentially includes a long sheet area, a transition area, a variable level area, a short sheet area, a variable level area, a transition area and a long sheet area along the stacking direction, the long sheet area is stacked by a plurality of first silicon steel sheets with equal length, the transition area is stacked by a plurality of second silicon steel sheets with equal length, the short sheet area is stacked by a plurality of third silicon steel sheets with equal length, the length of the first silicon steel sheet is greater than the length of the second silicon steel sheet, and the length of the second silicon steel sheet is greater than the length of the third silicon steel sheet; the variable level area is stacked by a plurality of variable level silicon steel sheets, the length of the variable level silicon steel sheet gradually increases from the length of the second silicon steel sheet to the length of the third silicon steel sheet, and the variable level area presents a circular arc surface on the side close to the core column, and the length difference between adjacent two variable level silicon steel sheets is less than 0.1 mm; The stacking thickness H2 of the transition area is obtained by the following steps: S1: Calculate the distance F between the short clamping piece and the variable level area by formula (1.1): （1.1）， Wherein, R is the radius of the core column, Q is the shortest distance between the body magnetic shielding assembly and the core column, W is the distance between the circular arc surface of the variable level area and the surface of the core column, L is the distance of the first silicon steel sheet from the center line in the length direction of the body magnetic shielding assembly, E is the height difference between the long sheet area and the transition area, and E is obtained by formula (1.2) in this step; E=M+G+P (1.2), Wherein, E is the height difference between the long sheet area and the transition area, M is the circular arc radius of the circular arc end of the short clamping piece, G is the width of the binding belt, and P is a constant value, which is 5-10 mm; S2: If F≥0 is calculated in S1, only one binding belt needs to be set, and then the stacking thickness H2 of the transition area is obtained by formula (1.3): H2=F+δ (1.3), Wherein, δ is the thickness of the short clamping piece; S3: If F<0 is calculated in S1, n binding belts need to be set, and the value of E is recalculated by formula (1.4): E=M+nG+(n-1)T+P (1.4), Wherein, T is the gap between two adjacent binding belts, and n≥2 is the number of binding belts; Then F is calculated by formula (1.1), and the stacking thickness H2 of the transition area is further obtained by formula (1.3); The value of Q is 17 mm, the value of W is 20 mm, and the value of L is 5 mm; When the capacity is small, a smaller value of P is taken, M=B, and G=50 mm, wherein B is the width of the silicon steel sheet; When the capacity is large, a larger value of P is taken, M=0.7B, and G=40 mm or 50 mm; According to the design requirements, the following parameters are given: the diameter D of the core column, the stacking thickness A of the silicon steel sheet, the width B of the silicon steel sheet, and the thickness δ of the clamping piece; The stacking thickness H1 of the long sheet area is obtained by formula (2.1): H1=A-(D+2Q+2δ) / 2 (2.1), Wherein, Q is the shortest distance between the body magnetic shielding assembly and the core column; The short piece area's stack thickness C is obtained by formula (2.2): （2.2）， Wherein, R is the radius of the core column, namely D / 2, W is the distance between the circular surface of the variable level area and the surface of the core column.

2. The magnetic shield assembly for a reactor body according to claim 1, characterized in that: The short clamping piece is arranged in the transition area, cooperates with the clamping piece to fix the silicon steel sheet, the short clamping piece is concave at one end of the transition area silicon steel sheet, cooperates with the second silicon steel sheet, and the other end of the short clamping piece is a circular arc.

3. The magnetic shield assembly for a reactor body according to claim 2, wherein: The short clamping piece and the clamping piece are fixed by at least one binding belt.

4. The magnetic shield assembly for a reactor body according to claim 2, wherein: The concave end of the short clamping piece and the second silicon steel sheet are insulated by Nomex paper.

5. The magnetic shield assembly for a reactor body according to claim 1, wherein: All the silicon steel sheets in the silicon steel sheet group and the clamping piece are stacked in a mold and fixed by epoxy resin bonding.

6. A reactor, characterized by The electric reactor comprises the body magnetic shielding assembly of any one of claims 1-5.

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