A core section optimization method based on integrated cutting process and its matching design margin

Abstract

A comprehensive nesting process and a core cross-section optimization method for supporting design margins in the present invention, the technical solution of which includes the following steps: The first step: Compare the data of the core step width and the order quantity with the inventory, and select the cores with sheet widths that do not meet the requirements; The second step: Judge the core cross-section morphology parameters including the core diameter and shape; The third step: Obtain the assembly allowance between the core and the winding, and confirm the process margin that can be occupied by the winding assembly; The fourth step: Confirm that the design levels are n levels and m levels; The fifth step: Judge whether Bm belongs to the subset of the optimized step width group; The sixth step: If Bm does not belong to the optimized step width group, then m = m + 1, and return to the fifth step; The seventh step: If Bm belongs to the optimized step width group, then Bm = Bm + 5, and find its step thickness Hm; The eighth step: Calculate whether the effective cross-sectional area meets the preset safety margin; The ninth step: Judge whether the step width and step thickness of the mth level exceed the maximum morphology size; The tenth step: Judge whether m < n, output the core cross-section step width and step thickness, and increase the effective cross-sectional area and safety margin.

Description

Technical Field

[0001] The invention relates to the field of design, production and manufacturing of power transformer cores, and in particular to a core cross-section optimization method with a comprehensive sleeve cutting process and a matching design margin. Background Art

[0002] The transformer core is an important component of the transformer, usually made of stacked silicon steel sheets. The main function of the core is to serve as the magnetic circuit part of the transformer, so that the electromagnetic induction of the transformer can be realized. Under the action of alternating current, self-inductance will be generated in the core, forming a closed loop, thereby playing the role of transferring energy. The design of the cross-sectional shape and size of the core also needs to be comprehensively considered according to factors such as the capacity, voltage level and cooling method of the transformer to ensure that the ampere-turns of the winding are evenly distributed and improve the electromagnetic performance of the transformer.

[0003] The purpose of transformer core cross-section design is to ensure the effective cross-sectional area so that the core works under reasonable magnetic density and the loss performance meets the standard. There are many types of core cross-section optimization design algorithms at present, including single-objective optimization algorithms with the maximum effective cross-sectional area as the goal and multi-objective optimization algorithms such as particle swarm optimization and genetic algorithm that combine cross-sectional area, iron loss and other factors. However, such algorithms often pursue the best no-load performance or utilization rate of the core from a design perspective, and iterate the core width and thickness according to the cross-sectional design diameter. However, when core processing manufacturers receive the combination of design and processing, they are often affected by factors such as production capacity, loss, and inventory. It is necessary to consider the inventory of the core cutting process to confirm the original design of the sheet width group to be optimized, and explore the design margin of the core and winding assembly to confirm the maximum shape and size of the core. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention discloses a core cross-section optimization method that integrates a sleeve cutting process and a matching design margin.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A core cross-section optimization method based on a comprehensive sleeve cutting process and its matching design margin, characterized in that it comprises the following steps:

[0007] Step 1: Collect the data of required core width B0, B1, ...Bn, core thickness H0, H1, ...Hn and order quantity, compare with the inventory, and select the core that does not meet the required width;

[0008] Step 2: According to the core step width B0, B1, ...Bn and the core step thickness H0, H1, ...Hn, determine the core cross-sectional morphology parameters including the core diameter and shape;

[0009] Step 3: Determine the assembly allowance between the iron core and the winding and the process margin available for winding assembly;

[0010] Step 4: Confirm that the design level is n levels, where n levels are for the iron core, and level m corresponds to the width Bm and thickness Hm of the level. m corresponds to the cycle level, with an initial m = 0;

[0011] Step 5: Determine whether Bm belongs to the subset of the optimized width group;

[0012] Step 6: If Bm does not belong to the optimized width group, then m = m + 1, and return to Step 5;

[0013] Step 7: If Bm belongs to the optimized width group, then Bm = Bm + 5, and calculate its thickness Hm;

[0014] Step 8: Calculate whether the effective cross-sectional area meets the preset safety margin. If it meets the preset safety margin, proceed to the next step; otherwise, return to Step 4;

[0015] Step 9: Determine whether the width and thickness of level m exceed the maximum profile size. If they meet the requirements of the maximum profile size, proceed to the next step; otherwise, adjust the value of Bm and return to Step 4;

[0016] Step 10: Determine whether m < n, and output the width and thickness of the iron core cross-section level.

[0017] Further, in Step 1, the inventory comparison data is the occupancy rate, occupancy duration, maximum width and minimum width of nested cutting.

[0018] Further, in Step 2, the shape of the iron core is a perfect circle, or an oblong circle, or an ellipse.

[0019] Further, in Step 3, the assembly allowance between the iron core and the winding ranges from 1 to 3 mm.

[0020] Further, in Step 3, the process margin ranges from 1 to 3 mm.

[0021] Further, in Step 8, if the calculated effective cross-sectional area is greater than the safety margin, proceed to Step 9.

[0022] Further, in Step 8, if the calculated effective cross-sectional area is less than or equal to the safety margin, change the return value to Bm = Bm - 5, m = m + 1, and re-enter Step 4.

[0023] Further, in Step 9, if the width and thickness of level m exceed the maximum profile size, the width of this level does not need to be changed, and proceed to Step 10.

[0024] Further, in Step 9, if either the width or the thickness of level m does not exceed the maximum profile size, return the value Bm = Bm - 5, m = m + 1, and enter Step 4.

[0025] Further, in the tenth step, if m < n is satisfied, return m = m + 1; otherwise, end the loop and output the core cross-section widths B0, B1... Bn and thicknesses H0, H1... Hn.

[0026] The beneficial effects of the present invention are as follows:

[0027] 1. Considering both inventory conditions and design margins, the widths and thicknesses of the core levels are selected to improve the utilization rate of inventory materials during the nested cutting process by the core manufacturer while ensuring the cross-section utilization rate.

[0028] 2. Among the widths screened by the judgment basis in the optimized sheet width group, the sheet widths with a mantissa of 5 are selected. During the process, the purpose of Bm + 5 is to adjust this sheet width to a mantissa of 0, and the sheet widths with a mantissa of 5 that can be optimized are optimized to a mantissa of 0. Due to the inventory raw materials, a mantissa of 0 is convenient for nested cutting production of the core, improving the overall utilization of materials.

[0029] 3. The purpose of the judgment condition in the eighth step is to determine whether the optimization of the core width of this level causes an increase or decrease in the effective cross-sectional area of the core. Yes means that this optimization can increase the effective cross-sectional area of the core and can be accepted to enter the next loop judgment. No means that the cross-sectional area of the core decreases, which is not allowed because a decrease in area will lead to an increase in iron loss.

[0030] 4. What is judged in the ninth step is whether it exceeds the maximum profile size. This is the second factor interfering with the optimization design judgment, the maximum profile size. Exceeding the maximum profile size means that the core and the coil cannot be assembled and is not acceptable.

[0031] 5. After optimization, the types of sheet widths of the core eliminate many newly opened coil materials necessary for the original design, instead consuming inventory, improving the overall inventory material turnover speed and utilization rate, and reducing inventory raw materials.

[0032] 6. When the cross-sectional area of the core increases and does not interfere with the assembly with the winding, its no-load loss performance is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a flowchart of the implementation of the core cross-section optimization method for the comprehensive nested cutting process and its supporting design margins.

[0034] Figure 2 It is a schematic cross-sectional view of the initial design of the core.

[0035] Figure 3 It is a schematic cross-sectional view of the optimized core. DETAILED DESCRIPTION OF THE INVENTION

[0036] EXAMPLE:

[0037] Currently, it is necessary to design a 630 kVA dry-type transformer core. The initial design cross-sectional diagram of this type of core is attached Figure 2 as shown.

[0038] A core section optimization method based on integrated cutting process and its matching design margin, such as Figure 1 As shown, the following steps are included:

[0039] Step 1: Collect the data of core width B0, B1, ...Bn, core thickness H0, H1, ...Hn and order quantity required on the original design drawings, and compare them with the inventory. The inventory comparison data is occupancy rate, occupancy time, maximum and minimum width of the nesting, and select the cores that do not meet the required width. Specifically, the core widths are 160mm, 155mm, 145mm, 135mm, 110mm, 100mm and 90mm. Combined with the silicon steel unwinding width of 500, the nesting process is adopted, and the comprehensive utilization rate of the existing inventory, the original design core section needs to be optimized. The width group is 155mm, 145mm and 135mm.

[0040] The original design drawings provided contain the following data:

[0041] Required core step width B0, B1, ...Bn, core step thickness H0, H1, ...Hn, minimum and maximum core sheet width, assembly allowance, process margin and design level n.

[0042] There are three principles for comparing and selecting raw steel strips:

[0043] First, consider the minimum and maximum sheet width. According to the minimum and maximum sheet width of the designed iron core, the raw steel strip that exceeds the minimum and maximum sheet width will be removed.

[0044] Second, consider the tail number of the raw steel strip and the tail number of the designed sheet width. If the tail number of the raw steel strip cannot be divided by the designed sheet width, optimize the sheet width design.

[0045] Third, consider the relationship between the designed sheet width and the raw steel strip width. If the difference between the designed sheet width and the raw steel strip width is too large, a large amount of processing allowance will be left, so optimize the sheet width design.

[0046] Step 2: If Figure 2 As shown, according to the core step width B0, B1, ... Bn and the core step thickness H0, H1, ... Hn, the core cross section is drawn, and the core cross section morphology parameters including the core diameter and shape are determined according to the drawing of the core cross section. The core shape is a perfect circle, an oblong, or an ellipse.

[0047] In this embodiment, the core step widths B0, B1, ... Bn are specifically 160mm, 155mm, 145mm, 135mm, 110mm, 100mm and 90mm, and the step thicknesses are 19.5mm, 14mm, 9mm, 10mm, 9.5mm and 9.5mm, and the corresponding inter-pole spacings are 272mm, 266mm, 247mm, 227mm, 209mm, 181mm and 142mm from outside to inside. Then, the core cross-sectional morphology parameters are determined, and the core diameter is 80, and the shape is oblong.

[0048] Step 3: Get the assembly margin of the core and winding, confirm that the winding assembly can occupy the process margin, and obtain the core and winding assembly margin range of 1 to 3mm. At the same time, confirm that the winding assembly can occupy the process margin of 3mm. The assembly margin is determined according to the design requirements of the original design drawings, and the process margin is determined according to the design requirements of the original design drawings. Combined with the original design core cross-sectional morphology parameters, the maximum cross-sectional morphology parameters of the core are obtained, as shown in the attached figure. Figure 3 shown.

[0049] Step 4: Confirm that the design level is n, which is determined according to the original design drawings. Level m corresponds to level width Bm and level thickness Hm, and the initial m = 0. Specifically confirm that the design level is 7, the main level corresponds to a level width of 160mm and a level thickness of 142mm, and the initial m = 0 to enter the main level sheet width optimization design.

[0050] Step 5: Determine whether Bm belongs to the optimized level width group subset.

[0051] Step 6: If Bm does not belong to the optimized level width group, then m=m+1, and return to step 5.

[0052] Step 7: If Bm belongs to the optimized step width group, then Bm=Bm+5, and calculate its step thickness Hm.

[0053] Step 8: Calculate whether the effective cross-sectional area satisfies the preset safety margin. If the calculated effective cross-sectional area is less than or equal to the safety margin, return the value Bm=Bm-5, m=m+1 and re-enter step 4. If the calculated effective cross-sectional area is greater than the safety margin, proceed to step 9.

[0054] Step 9: Determine whether the m-level width and thickness exceed the maximum morphological size. If the m-level width and thickness exceed the maximum morphological size, the width of the level does not need to be changed, and go to step 10; if one of the m-level width and thickness does not exceed the maximum morphological size, return the value Bm=Bm-5, m=m+1 and go to step 4.

[0055] Step 10: Determine if m < n, and output the width and thickness of the iron core cross-section levels. Finally, output the widths of the newly designed iron core cross-section levels as 160 mm, 155 mm, 150 mm, 140 mm, 110 mm, 100 mm, and 90 mm, and the thicknesses as 14.2 mm, 19.5 mm, 14 mm, 9 mm, 10 mm, 9.5 mm, and 5.5 mm. The corresponding pole pitch from the outside to the inside is 277 mm, 266 mm, 247 mm, 227 mm, 209 mm, 181 mm, and 142 mm in sequence. The reference for the optimized iron core cross-section shape is attached Figure 3 。

[0056] Compared with the original design, the optimized iron core design, on the basis of the original design,

[0057] the cross-sectional area of the iron core increases, and at the same time, it does not interfere with the winding assembly and is easier to process.

[0058] On the other hand, the increase in the cross-sectional area of the iron core improves the no-load loss performance of the transformer. The main reasons are as follows.

[0059] The magnetic flux density decreases: When the cross-sectional area of the iron core increases, the magnetic flux density decreases accordingly. This is because the magnetic flux is distributed over a larger cross-section, thus reducing the magnetic flux density per unit area. The decrease in the magnetic flux density can reduce the eddy current loss and hysteresis loss in the iron core, and thus reduce the no-load loss.

[0060] The iron loss decreases: The iron loss is the main part of the no-load loss and consists of eddy current loss and hysteresis loss. The eddy current loss is caused by the induced current generated by the change of the magnetic flux in the iron core, and the hysteresis loss is the energy loss due to the magnetization process of the iron core material. When the cross-sectional area of the iron core increases, the magnetic flux per unit volume decreases, thus reducing the eddy current loss and hysteresis loss, and further reducing the no-load loss.

[0061] Calculation method of no-load loss, loss = K * P * G

[0062] K is the process coefficient, P is the loss of silicon steel per unit weight, and G is the weight of the iron core. Taking the example as an example, G increases by 1.2%, P is a non-linear curve related to the magnetic flux density, P decreases by 3%, and the overall loss decreases by 2%. Therefore, the no-load performance is better.

[0063] Example 2:

[0064] The difference from Example 1 is:

[0065] Before optimization, the widths of the laminations are 140 mm, 130 mm, 120 mm, 115 mm, 100 mm, 90 mm, and the corresponding thicknesses of the levels are 140 mm, 25 mm, 10 mm, 5 mm, 9 mm, 5 mm.

[0066] The lamination width group to be optimized is 115, with an oval cross-section design and a design margin of 3 mm.

[0067] After output optimization, the sheet widths of 140mm, 130mm, 120mm, 100mm, and 90mm correspond to grade thicknesses of 140mm, 25mm, 15mm, 9mm, and 5mm.

[0068] To sum up, after placing an order, we will make a judgment based on its specific size and select raw materials with a width ending in 5 or a width ending in 0 in the inventory to make full use of the materials, maximize the utilization rate of the raw materials and reduce inventory backlogs.

[0069] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0070] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A core section optimization method with integrated cutting process and its matching design margin, characterized in that: It includes the following steps: The first step: Collect data on the required core widths B0, B1, ... Bn, core thicknesses H0, H1, ... Hn, and order quantity, compare with the inventory, and select the cores with non-compliant sheet widths; The second step: Based on the core widths B0, B1, ... Bn and core thicknesses H0, H1, ... Hn, judge the core cross-section morphology parameters including the core diameter and shape; The third step: Determine the assembly allowance between the core and the winding and the process margin available for winding assembly; The fourth step: Confirm that the design level is n levels, the n levels are cores, the m levels correspond to the core widths Bm and core thicknesses Hm, m corresponds to the cycle level, and the initial m = 0; The fifth step: Judge whether Bm belongs to the subset of the optimized core width group; The sixth step: If Bm does not belong to the optimized core width group, then m = m + 1, and return to the fifth step; The seventh step: If Bm belongs to the optimized core width group, then Bm = Bm + 5, and calculate its core thickness Hm; The eighth step: Calculate whether the effective cross-sectional area meets the preset safety margin. If it meets the preset safety margin, proceed to the next step. Otherwise, return to the fourth step; In the eighth step, when the calculated effective cross-sectional area is greater than the safety margin, proceed to the ninth step; In the eighth step, when the calculated effective cross-sectional area is less than or equal to the safety margin, change and return the value Bm = Bm - 5, m = m + 1 and re-enter the fourth step; The ninth step: Judge whether the core width and core thickness of the m level exceed the maximum morphology size. If they meet the maximum morphology size requirements, proceed to the next step. Otherwise, adjust the value of Bm and return to the fourth step; In the ninth step, if one of the core width and core thickness of the m level does not exceed the maximum morphology size, return the value Bm = Bm - 5, m = m + 1 and enter the fourth step; The tenth step: Judge whether m < n, and output the core cross-section width and core thickness; In the tenth step, if m < n is satisfied, return m = m + 1. Otherwise, the loop ends, and output the core cross-section widths B0, B1…Bn and core thicknesses H0, H1…Hn.

2. The integrated set-cutting process and the method for optimizing the core cross-section with the matching design margin according to claim 1 are characterized in that: In the first step, the inventory comparison data are occupancy rate, occupation duration, maximum and minimum sheet widths for nesting; 3. The integrated set-cutting process and the method for optimizing the core cross-section with the matching design margin according to claim 1 are characterized in that: In the second step, the shape of the core is a perfect circle, or an oblong circle, or an ellipse; 4. The integrated cutting process and the method for optimizing the core cross section with the matching design margin according to claim 1 are characterized in that: In the third step, the assembly allowance between the core and the winding ranges from 1 to 3 mm; 5. The integrated set-cutting process and the method for optimizing the core cross-section with the matching design margin according to claim 1 are characterized in that: In the third step, the process margin ranges from 1 to 3 mm.

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