RU2777051C1 - Magnetic core of a three-phase magnetic induction apparatus and magnetic core frame - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to three-phase magnetic induction apparatus, in particular, to cores with a magnetic circuit, used in transformers, coils, throttle valves. Magnetic core of a three-phase magnetic induction apparatus comprises three frames, wherein each frame is made of a strip of a magnetic material. Said frames are arranged in the magnetic core so that the external surfaces of the frames face each other, structurally forming a triangular prism. Each of the frames is formed by a multilayer structure, each layer whereof is represented by a rectangular spiral with a pitch of 0.1 to 0.3 of the thickness of the strip laid so as to form such stepped structures on the internal and external surfaces of the frame that the internal part of said structure forms an approximated circumference and the external part thereof forms a plane at an angle of 30 degrees to the plane of the frame, displaced from the centre of said circumference. The stepped structures of one frame do not come into contact with the stepped structures of the adjacent frames, forming a gap between said frames.

EFFECT: increase in the manufacturability and reduction in losses in the loop closure gaps.

2 cl, 4 dwg

Description

The present invention relates to three-phase magnetic induction devices, in particular to cores with a magnetic circuit used in devices such as transformers, coils, chokes.

From European Patent Publication No. EP 2395521 a method is known for manufacturing triangular cores of transformers from an amorphous metal strip, wherein the arms of the magnetic core are in the form of a triangle, and the cross section of the arms of the core has a round or polygonal shape. In order to obtain core frame arms with the required cross-sectional shape, said core frames are made from layers of continuously wound tape, the tape width being adjusted depending on the dimensions of the respective core arm layer by means of laser cutting.

The disadvantage is that the molten material, usually formed during such laser cutting of an amorphous tape, leads to the formation of melted defects on the cut edge, which, in turn, leads to the appearance of unnecessary gaps between the layers of the magnetic tape during its winding, which reduces the density winding. In addition, such defects can create conditions for the occurrence of short circuits during the operation of the magnetic system, which increases the eddy current losses. It should also be noted that such a method of manufacturing a magnetic core with a variable cross section is extremely complicated, and its implementation is difficult.

The closest are the magnetic core of a three-phase magnetic induction device and its frames (RU No. 2635098, publ. 11/09/2017), moreover, the specified magnetic core contains three frames of the magnetic core, forming the arms of the magnetic core for installing coils of the induction device on them, each of the frames core is made of a wound tape of magnetic material, characterized in that:

- each of the frames of the core is made of several separate multilayer loops, the width of each of which is different from the width of other loops in the specified frame;

wherein each loop of the frame is individually made from a wound tape of magnetic material having a predetermined tape width defining the thickness of said loop;

- moreover, several loops forming the frame are coaxially stacked on top of each other so as to ensure the formation of stepped structures on the inner and outer surfaces of the frame,

- moreover, the frames of the magnetic core are located in the specified magnetic core so that the inner surfaces of the frames face each other, thereby forming a structure having the shape of a triangular prism, and the stepped structure of each frame is engaged with the stepped structures of the frames locally adjacent to it, thereby forming three arm of the magnetic core for installing the coils of the specified device.

The disadvantage is that a perturbation of the magnetic flux occurs at the junctions of the loops, which entails increased magnetic losses during operation of the device. Also, the formation of individual loops requires the use of an additional tool and increased time consumption, which reduces manufacturability.

It is also a disadvantage that in order to close two independent stepped structures, it is necessary to repeat the step of the layers on both structures. In addition, clamping requires the manufacture of these surfaces with increased accuracy, which entails an increase in manufacturing time, the complexity of tooling for manufacturing, and a general decrease in manufacturability.

The technical result consists in increasing manufacturability and reducing losses in the gaps of closing the loops by creating such a design of the device in which each frame of the magnetic core will be made of a continuous tape, and each layer of the magnetic core will be a rectangular spiral with rounded corners. Continuity will help avoid joints along the length of the loops, and will also speed up the production of magnetic core layers.

The same, pre-formed, width of the tape along the entire length of the spiral will avoid the formation of defects during the formation of the layer.

The use of several frames for the production of magnetic induction devices that do not involve engagement with each other, but have an air gap between them, provided by the design of the device, also entails an increase in manufacturability and a decrease in transverse losses in the core.

The technical result is achieved:

- a magnetic core of a three-phase magnetic induction device having three magnetic core frames, each of the core frames being made of a strip of magnetic material, the magnetic core frames being located in said magnetic core so that the outer surfaces of the frames face each other, thereby forming a structure having the shape of a triangular prism. Each of the frames of the core is formed by a multilayer structure, each layer of which is represented by a rectangular spiral with a step of 0.1-0.3 of the thickness of the tape, laid so as to ensure the formation of such stepped structures on the inner and outer surfaces of the frame that the inner part of this structure forms an approximate circle , and the outer part forms a plane at an angle of 30 degrees to the plane of the frame, offset from the center of this circle. The stepped structures of one frame do not contact with the stepped structures of the frames adjacent to it, forming a gap between them, and also forming a figure tending to the shape of a circle in the cross section of a triangular prism rib and three arms of the magnetic core.

- a magnetic core frame made of a tape of magnetic material, the frame being formed by a multilayer structure, each layer of which is represented by a rectangular helix with a step of 0.1-0.3 of the tape thickness, laid so as to ensure the formation of such stepped structures on the inner and outer surfaces of the frame that the inner part of this structure forms an approximate circle, and the outer part forms a plane at an angle of 30 degrees to the plane of the frame, offset from the center of this circle.

The design of the device implies the absence of direct engagement of the magnetic core frames. The frames have an air gap in the place of their convergence, provided constructively. The air gap prevents the occurrence of transverse currents in the magnetic core, which reduces the remagnetization losses of the device. In addition, this solution makes it possible to avoid the need to repeat the step of layers on independent structures, reduces the requirement for the accuracy of their manufacture, which entails a reduction in manufacturing time and an increase in manufacturability.

The proposed utility model is illustrated by drawings, where Fig. 1 shows the magnetic core of a three-phase magnetic induction device, Fig. 2 - frame of the core of the magnetic induction device, in Fig. 3 is a diagram of the formation of the frame of the core of the magnetic induction device, in Fig. 4 is a schematic representation of the frame layer of a continuously wound tape magnetic core.

The device consists of three frames 1, the frames 1 being located in the magnetic core so that the outer surfaces of the frames face each other, thereby forming a structure having the shape of a triangular prism.

Each of the frames 1 is formed by a multilayer structure, each layer 2 of which is represented by a rectangular spiral with a step of 0.1-0.3 of the thickness of the tape, laid so as to ensure the formation on the inner and outer surfaces of the frame 1 such stepped structures that the inner part of this structure forms an approximate circle, and the outer part forms a plane at an angle of 30 degrees to the plane of the frame with an offset from the center of this circle, and the stepped structures of one frame do not contact with the stepped structures of the frames locally adjoining it, forming a gap between them and three arms of the magnetic core.

The device is manufactured as follows. A tape made of amorphous metal, providing tension with the help of a mechanical tensioner, is wound on a rectangular tooling, with dimensions corresponding to the calculated data. Thus, alternately forming the required number of layers. A schematic representation of such a layer is shown in Fig. 4. The number of layers is calculated based on the width of the tape and the required total cross section of the core. Then heat treatment is carried out to relieve internal stresses in the tape after winding. After that, the layers are laid symmetrically to each other, in accordance with the calculated data, forming the frame of the core. An example of laying is shown in Fig. 3. The frame of the core thus formed is impregnated with varnish. After the varnish dries, the frame becomes fully formed. An example of the formed frame is shown in Fig. 2.

For the manufacture of various electromagnetic devices, it is necessary to produce a different number of such frames. For example, for the manufacture of a three-phase distribution network transformer, three such cores are needed. Frames are arranged in space using various design solutions. The mutual arrangement of the frames is shown in Fig. one.

Claims (2)

1. A magnetic core of a three-phase magnetic induction device having three magnetic core frames, each of the core frames being made of a strip of magnetic material, the magnetic core frames being disposed in said magnetic core so that the outer surfaces of the frames face each other, thereby forming a structure, having the shape of a triangular prism, characterized in that each of the frames of the core is formed by a multilayer structure, each layer of which is represented by a rectangular helix with a step of 0.1-0.3 of the thickness of the tape, laid so as to ensure the formation of such stepped structures on the inner and outer surfaces of the frame that the inner part of this structure forms an approximate circle, and the outer part forms a plane at an angle of 30 degrees to the plane of the frame with an offset from the center of this circle, and the stepped structures of one frame do not contact with the stepped structures of adjacent frames, forming a gap between n them, as well as forming a figure with a total cross section, tending to the shape of a circle in the cross section of the rib of a triangular prism, and three arms of the magnetic core. 2. The frame of the magnetic core, made of a tape of magnetic material, characterized in that the frame is formed by a multilayer structure, each layer of which is represented by a rectangular spiral with a step of 0.1-0.3 of the thickness of the tape, laid so as to ensure the formation on the inner and outer surfaces frames are such stepped structures that the inner part of this structure forms an approximate circle, and the outer part forms a plane at an angle of 30 degrees to the plane of the frame with an offset from the center of this circle.

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