CN113436873B - A manufacturing process of three-dimensional winding transformer core - Google Patents

Abstract

The invention belongs to the technical field of transformers, and particularly relates to a manufacturing process of a three-dimensional wound transformer core. A manufacturing process of a three-dimensional winding transformer iron core mainly comprises two parts: firstly, manufacturing a single-frame iron core, and then combining the single-frame iron cores into a three-phase three-dimensional wound iron core. Two parts are required for manufacturing the single-frame iron core: 1. selecting a proper strip with a conventional width, and winding the strip on a die with a certain outline dimension through an arc surface to form a basic shape of the iron core; 2. and performing linear cutting on the wound strip to finish the final single-frame iron core molding. The invention provides a manufacturing process of a three-dimensional wound transformer iron core, which has the advantages of low cost and simple process.

Description

A manufacturing process of a three-dimensional wound transformer core

technical field

The invention belongs to the technical field of transformers, and in particular relates to a manufacturing process of a three-dimensional winding transformer core.

Background technique

With the continuous improvement of the technical level, amorphous alloy transformers have been widely used in the field of power distribution, and the technology of amorphous alloy three-dimensional wound core transformers has developed rapidly. The three-dimensional wound core transformer is a high-efficiency and energy-saving transformer developed in recent years, and the processing technology of the wound core is more suitable for the use of magnetic steel strips with thin specifications, high magnetic induction, and ultra-low loss. With favorable conditions, it can reach the first-level and second-level energy efficiency of the latest national "Power Transformer Energy Efficiency Limits and Energy Efficiency Grades 20052-2020" standard.

The amorphous three-dimensional wound core is mainly composed of a number of trapezoidal strips of different sizes that are successively wound to obtain three rectangular core frames 1 with approximately semicircular cross-sections and identical geometric dimensions (see Figure 1). The same side of the core frame 1 is spliced in pairs. After splicing, the three core columns of the core are arranged in an equilateral triangle. The cross-section of the core core is close to a circle. The lengths of the magnetic circuits of the three cores are the same, and the length of the iron yoke is the shortest. Therefore, the core is light in weight and the no-load loss is small. The production process from the core to the coil is quite different from the traditional laminated core, requiring special manufacturing equipment, and the degree of automation has also made significant progress.

At present, the single-frame core of the three-dimensional winding transformer on the market needs to be successively wound with trapezoidal materials of different sizes, and the acquisition of these trapezoidal strips of different sizes needs to be cut obliquely first, and then through special winding equipment and The mold is coiled. The process is complicated, and special non-standard oblique shear equipment needs to be designed. The winding process requires high control precision, and the winding equipment is complicated, which invisibly increases the manufacturing cost of the three-dimensional winding transformer. Therefore, it is necessary to propose a brand-new solution that can realize the three-dimensional winding transformer solution, but the requirements for control accuracy and equipment in the process do not need to be too high, and at the same time, the production cost of the three-dimensional winding transformer can be reduced as a whole.

Contents of the invention

In order to solve the problems existing in the above-mentioned background technology, the present invention proposes a three-dimensional winding transformer core manufacturing process, which makes the three-dimensional winding transformer core manufacturing process simpler and lower in cost; the three-dimensional winding transformer core has the same weight as its yoke The cross-sectional area is larger than the magnetic density of the yoke of the three-dimensional wound core of the traditional solution, which will make the overall iron loss smaller.

The invention has the advantages of low cost and simple process.

A three-dimensional winding transformer core, its special feature is that,

It includes three single-frame iron cores with the same structure. The single-frame iron core includes left-right symmetrical iron core posts and up-and-down symmetrical iron yokes. The left-right symmetrical iron core posts and up-down symmetrical iron yokes together form a rectangular window.

The single-frame iron core is formed by coiling strips, and two adjacent layers of strips are misplaced and wound. The strips are wound so that both sides of the single-frame iron core are curved surfaces, and the inner side of the core column of the single-frame iron core is a slope.

Each single-frame core is connected with the other two single-frame cores through core columns to form a three-phase three-dimensional wound core structure, and the inclined surfaces of the core columns of two adjacent single-frame cores are bonded together.

Further, the above-mentioned single-frame iron core is formed by winding strips of the same width.

Further, the above strip is an amorphous alloy strip.

Further, the above-mentioned single-frame iron core needs to be dipped in paint.

Further, the slope inside the core column of the single-frame iron core is processed by wire cutting.

A transformer, which is special in that it includes any one of the above-mentioned three-dimensional wound transformer cores.

The technical solution of the present invention to solve the above problems is: a manufacturing process of a three-dimensional wound transformer core, which is special in that it includes the following steps:

S1: Install the inner mold of the winding core on the core winding machine;

S2: Introduce strips of appropriate width (according to the specific core design size);

S3: The winding machine automatically winds according to the design size of the iron core;

S4: After the single-frame iron core is wound to meet the design requirements, the strip is cut, and it is lifted from the winding machine together with the winding inner mold and the iron core;

S5: Make the ring-shaped core into a rectangular shape, and fix it with an external mold to complete the production of a single-frame core;

S6: Repeat operations S2-S5 to complete the other two single-frame cores;

S7: Select a special annealing furnace, and anneal the iron core with the mold. Its advantage is that the single frame is heat-treated separately, the operation is simple, and it can be produced on a large scale.

S8: Select the appropriate impregnating material and impregnate the single-frame iron core. The advantage is to realize the structural strength of the single-frame iron core, which is convenient for wire cutting, and does not worry about the gap between strip layers and rust. Moreover, the probability of mechanical damage to the iron core during transportation and transformer assembly is greatly reduced, ensuring product quality.

S9: According to the design requirements of the core structure, the core column of the core is cut with a bevel to meet the requirements of three-phase core splicing. Compared with the traditional three-dimensional iron core for oblique shearing of the strip, this process method has higher production efficiency, better core size control accuracy, and simple operation.

S10: Use a special core combination device to combine three single-frame cores into a three-phase three-dimensional wound core structure.

Further, in the above step S2, the width of the strip is fixed.

Further, in the above step S3, during winding, the requirements for tight and smooth winding of the strip are achieved through control of the tension force of the strip and the control of the pressing force of the core winding strip.

Further, in the above step S2, the strip is an amorphous strip.

Further, in the above step S4, two adjacent layers of strips are wound in a dislocation, and the strips are wound so that both sides of the single-frame iron core are arcuate surfaces.

Advantages of the present invention:

The invention discloses a method for manufacturing a three-dimensional winding transformer iron core, which adopts strips of the same width for winding, and then conducts wire cutting as a whole after the core column of the iron core is wound into an arc surface. Compared with the traditional three-dimensional iron core, the strip is obliquely cut, and the production efficiency is improved. Higher, better core size control accuracy, and simple operation; this new method of winding and wire cutting amorphous three-dimensional wound core is simpler than the traditional three-dimensional winding process, reducing the complexity of the process and equipment , which further reduces production costs and contributes to the country's energy saving, emission reduction, and environmental pollution reduction.

The present invention is a three-dimensional wound transformer core. The maximum output power of the iron core with the same weight is equivalent to that of the three-dimensional wound iron core of the traditional solution; Under the same current density, the amount of copper used is smaller; under the same amount of copper used, the output power is greater; the cross-sectional area of the yoke of the iron core with the same weight is larger than the magnetic density of the yoke of the three-dimensional wound core of the traditional solution, which is It will make the overall iron loss smaller.

Description of drawings

Fig. 1 is the existing traditional three-dimensional winding transformer core;

Fig. 2 is a schematic diagram of the workflow of the present invention;

Fig. 3 is the structural representation of the single frame iron core that the inventive method makes;

Fig. 4 is another direction view of Fig. 3;

Fig. 5 is a schematic diagram of a three-dimensional volume transformer core made by the method of the present invention;

Fig. 6 is the existing traditional three-dimensional wound core magnetic circuit;

Fig. 7 is a software simulation diagram of the cross-sectional area of a traditional three-dimensional winding transformer core and the three-dimensional winding transformer core of the present invention;

Fig. 8 is a window area diagram of a traditional three-dimensional winding transformer core and the three-dimensional winding transformer iron core of the present invention;

Fig. 9 is a simulation diagram of the magnetic flux density of a traditional three-dimensional winding transformer core and the three-dimensional winding transformer core of the present invention;

Fig. 10 is a simulation diagram of the current density of the traditional three-dimensional wound transformer core and the three-dimensional wound transformer core of the present invention.

Among them, 1-single-frame iron core, 2-iron yoke, 3-iron core column, 4, arc surface, 5, inclined plane.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments It is some embodiments of the present invention, but not all of them. Based on the implementation manners in the present invention, all other implementation manners obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention. Accordingly, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention.

Referring to FIG. 2 , a manufacturing method of a three-dimensional coiled transformer core includes two parts: first manufacturing a single-frame core 1 , and then combining the single-frame cores 1 into a three-phase three-dimensional coiled core.

Two parts are required to make the single-frame iron core 1: 1. Select a strip material with a suitable conventional width, and wind it on a mold with a certain external size through the arc surface 4 to form the basic shape of the iron core; 2. The strip is wire-cut to complete the final forming of the single-frame iron core 1 .

Making the single-frame iron core 1 specifically includes the following steps:

S1: Install the inner mold of the winding core on the core winding machine;

S2: Introduce strips of appropriate width (according to the specific core design size); by selecting an appropriate bandwidth, the control of winding positioning and shape and the design of the inner window mold are important guarantees for this step;

S3: The winding machine automatically winds according to the design size of the iron core;

S4: After the single-frame core 1 is wound to meet the design requirements, the strip is cut, and it is lifted from the winding machine together with the winding inner mold and the core;

S5: Making the annular iron core into a rectangular shape, forming left-right symmetrical iron core columns 3 and up-and-down symmetrical iron yokes 2, and fixing them with an external mold to complete the production of a single-frame iron core 1;

S6: Repeat operations S2-S5 to complete the other two single-frame cores 1;

S7: Select the special annealing furnace for alloy iron core, and anneal the iron core with the mold. Its advantage is that the single frame is heat-treated separately, the operation is simple, and it can be produced on a large scale.

S8: Select a suitable impregnating material and impregnate the single-frame iron core 1 with varnish. The advantage is to realize the structural strength of the single-frame iron core 1, which is convenient for wire cutting, and there is no need to worry about the gap between layers of the strip and rust. Moreover, the probability of mechanical damage to the iron core during transportation and transformer assembly is greatly reduced, ensuring product quality.

S9: According to the design requirements of the core structure, the bevel 5 is cut for each core column of the single-frame core 1 to meet the requirements of three-phase core assembly. Compared with the traditional three-dimensional iron core for oblique shearing of the strip, this process method has higher production efficiency, better core size control accuracy, and simple operation.

As a preferred embodiment of the present invention, in the above step S2, the width of the strip is fixed.

As a preferred embodiment of the present invention, in the above step S3, during winding, the requirements for tight and smooth winding of the strip are achieved through the control of the tension force of the strip and the control of the pressing force of the core winding strip. .

As a preferred embodiment of the present invention, in the above step S2, the strip is an amorphous strip.

As a preferred embodiment of the present invention, in the above step S4, two consecutive layers of strips are wound in dislocation, and the strips are wound into a single-frame iron core 1 with arc surfaces 4 on both sides, see Fig. 3 and Fig. 4 .

Compared with the traditional three-dimensional rolling process, the present invention adopts the same width of the strip, saves the process time and cost of oblique cutting of the strip, and reduces the technical difficulty of the winding machine.

Finally, the single-frame core 1 is combined into a three-phase three-dimensional wound core, specifically:

The core posts 3 of two adjacent single-frame cores 1 are bonded together by cutting inclined surfaces 5 , and the three single-frame cores 1 are combined into a three-phase three-dimensional wound core structure by using a special core assembly device.

Structural Performance Test of Three-Phase Three-Dimensional Wound Core

The performance test of the finished amorphous three-dimensional wound core made by the above method mainly involves a B value test on three different sections, including qualitative test and quantitative test. Including testing whether the curve of B is smooth, whether there are distortion points, and whether the three phases are symmetrical. And quantitative testing, that is, whether the B value at a given voltage meets the design requirements.

The process method of this new type of winding and wire cutting amorphous three-dimensional wound core is simpler than the traditional three-dimensional winding process, which reduces the complexity of the process and equipment, which further reduces the production cost and contributes to the country's energy saving and emission reduction. Contribute to the reduction of environmental pollution.

Referring to Fig. 5, a three-dimensional winding transformer core is made by the above-mentioned method, and includes three single-frame cores 1 with the same structure. The symmetrical iron core column 3 and the up-and-down symmetrical iron yoke 2 together form a rectangular window. The single-frame iron core 1 is formed by winding a strip, and two adjacent layers of strip are wound in dislocation, and the strip is wound into a single-frame iron core. The two sides of 1 are curved surfaces 4, and the inner side of the core column 3 of the single-frame iron core 1 is a slope 5. Each single-frame core 1 is connected with other two single-frame cores 1 through core columns 3 to form a three-phase three-dimensional wound core structure, and the inclined surfaces of the core columns of two adjacent single-frame cores 1 are bonded together.

As a preferred embodiment of the present invention, the above-mentioned single-frame iron core 1 is formed by winding strips of the same width.

As a preferred embodiment of the present invention, the above strip is an amorphous alloy strip.

As a preferred embodiment of the present invention, the above-mentioned single-frame iron core 1 needs to be dipped in paint.

As a preferred embodiment of the present invention, the slope inside the core column 3 of the above-mentioned single-frame iron core 1 is processed by wire cutting.

A transformer comprising any one of the above-mentioned three-dimensional wound transformer cores.

Traditional three-dimensional wound core magnetic circuit: The traditional three-phase three-dimensional wound core is composed of three planar wound cores with mutually independent magnetic circuits, and the core column 3 of each phase winding is composed of two wound cores connected in parallel, as shown in Figure 6. The cross-sectional area of the yoke and the core of the traditional three-dimensional roll are equal, but a larger magnetic flux flows in. This part of the magnetic flux does not contribute to the excitation voltage, but will cause greater iron loss. The calculation method is :

Obviously, when calculating the loss and excitation current in the core, the core flux density Bm(AB) should be used instead of the flux density Bm. Otherwise, the calculated no-load loss and excitation current will be significantly smaller than the actual value.

However, in the solution of the three-dimensional wound transformer iron core provided by the present invention, since wire cutting with a certain degree of freedom can be performed, the relative section ratio of the yoke is larger.

Taking a traditional three-dimensional wound amorphous transformer core with a capacity of 400KVA and the three-dimensional wound amorphous transformer core provided by the present invention as an example, with reference to Figures 7-10, their parameters are calculated, and the parameters of the two are compared in Table 1:

Table 1

Table 2 shows the test results of a given pure resistive load for the traditional three-dimensional wound amorphous transformer core. Table 3 shows the test results of a given pure resistance load for the iron core of the three-dimensional wound amorphous transformer provided by the present invention.

Table 2

given load resistance input power Output Power copper loss Iron loss efficiency 0.38 398307.824 387867.803 5702 256 0.959437528 0.5R 306556.26 297050.6748 3450 211 0.95755689

table 3

given load resistance input power Output Power copper loss Iron loss efficiency 0.38 398407.835 387868.9 5695 242 0.959437528 0.5R 306756.45 297050.8 3436 206 0.95755689

Under the same given conditions, the three-dimensional wound amorphous transformer core provided by the invention and the traditional three-dimensional wound amorphous transformer core have equivalent output power and efficiency, and the copper loss and iron loss of the wire-cut three-dimensional wound are slightly smaller. The three-dimensional rolls of the two schemes have the same weight, the three-dimensional rolls of the wire-cut method and the traditional winding method have almost the same performance, but the cross-section of the core column of the wire-cut method is relatively small, which can effectively reduce the number of windings. The amount of copper used reduces the overall cost. In addition, the wire cutting method has simple process and high forming precision. The finished product saves materials, reduces production costs, and contributes to the country's energy saving, emission reduction, and environmental pollution reduction.

The above is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process conversion made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related systems fields, all of which are equally included in the scope of patent protection of the present invention.

Claims (4)

1. A manufacturing process for a three-dimensional winding transformer core, characterized in that, comprising the following steps: S1: Install the inner mold of the winding core on the core winding machine; S2: introduction of strips of fixed width; S3: The winding machine automatically winds a circular core according to the design size of the core; S4: Two layers of connected strips are wound in dislocation. The strips are wound into a single-frame iron core with arc surfaces on both sides. After the ring-shaped iron core is wound to meet the design requirements, the strips are cut, together with the winding inner mold and The iron core is hoisted away from the winding machine together; S5: Make the ring-shaped core into a rectangular shape, and fix it with an external mold to complete the production of a single-frame core; S6: Repeat steps S2-S5 to complete the other two single-frame cores; S7: using the annealing furnace to anneal the iron core with the mold; S8: impregnating the single-frame iron core; S9: Cut the inner side of the iron core column of the single-frame iron core into a bevel to meet the requirements of three-phase iron core splicing; S10: The inclined surfaces of the core columns of two adjacent single-frame cores are laminated, and the three single-frame cores are combined into a three-phase three-dimensional wound core structure. 2. A three-dimensional wound transformer core manufacturing process according to claim 1, characterized in that: In the step S3, during winding, the requirement of tight and smooth winding of the strip is achieved by controlling the tension force of the strip and the pressing force of the core winding strip. 3. A three-dimensional wound transformer core manufacturing process according to claim 1 or 2, characterized in that: In the step S2, the strip is an amorphous alloy strip. 4. A three-dimensional wound transformer core manufacturing process according to claim 3, characterized in that: The annealing furnace in step S7 is a dedicated annealing furnace for amorphous alloy cores.

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