JPH04109609A - Rolled sheet transformer - Google Patents

Abstract

PURPOSE:To increase the degree of freedom of design by piling sheet conductors consisting of two or more sorts of conductors of different current densities. CONSTITUTION:A sheet conductor 10 is made by laying two or more sorts of conductors of different current densities on top of each other. For example, the sheet conductor 10 is made of low-current-density, wide first sheet conductors 10a and high-current-density, narrow second sheet conductors 10b, with a plurality of narrow second sheet conductors 10b arranged in parallel at the outside of each of the wide first sheet conductors 10a to approximately the same width. Thereby the thickness of the component conductor can be changed according to a current value required by a rolled sheet transformer and the thickness of the sheet conductor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a sheet-wound transformer formed by winding a sheet conductor and an insulating film.

(Prior art) Sheet-wound transformers using sheet windings in which sheet conductors and insulating films are layered and wound around core legs have a good space factor for the wound conductors, so Compared to transformers using conductors, it is suitable for being smaller and lighter, and is widely used mainly for relatively low voltage and small capacity transformers of about 100 KVA. . In addition, recently, in view of its characteristics, research has been conducted into applying it to higher voltage, larger-sized transformers.

In such a sheet-wound transformer, as shown in FIG. 4, a sheet conductor 2 and an insulating film 1 are wound in an overlapping manner. In addition, the upper and lower ends of the insulating film 1 are connected to the sheet conductor 2.
Its width is wide so that it protrudes outward from the upper and lower ends. Furthermore, at the upper and lower ends of the insulating film 1, gaps between adjacent insulating films are filled with an insulator 3.

(Problems to be Solved by the Invention) However, the conventional sheet-wound transformer as described above has the following problems to be solved. That is, since the thickness of the sheet conductor 2 is usually five times or more thicker than the insulating film 1, it greatly influences the dimensions of the entire winding.

Moreover, once the material of the sheet conductor 2 is determined, the maximum current density that the material allows is also determined, and therefore the permissible value of the sheet-wound transformer is also limited. Further, when it becomes necessary to change the dimensions of the winding, even if an attempt is made to change the material used for the sheet conductor, a sheet conductor of the required width or thickness may not be available.

In this way, when designing a sheet-wound transformer, once the current is determined, the thickness of the sheet conductor is determined, which naturally determines the size and impedance of the transformer winding, which limits the degree of freedom in design. It had the disadvantage of becoming a nuisance.

Furthermore, in recent years, ribbon-shaped or narrow-width superconducting sheets have been proposed, but since these superconducting sheets are made of ceramic, it is extremely difficult to obtain wide ones like the conventionally used aluminum sheets. It is difficult to On the other hand, since the current density is high, it is clear that it greatly contributes to making the transformer more compact.

Therefore, it is possible to construct the winding using a copper sheet with a high current density like the superconducting sheet mentioned above, but it is not possible to obtain a wide copper sheet, so a narrow copper sheet is used together with an insulating film. It was very difficult to wind it to form a sheet-wound transformer.

The present invention was made to solve the above-mentioned problems, and its purpose is to make it possible to change the thickness of the sheet conductor as appropriate even when the current is determined when designing a transformer. The object of the present invention is to provide a sheet-wound transformer that can be used with a large degree of freedom in design.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a sheet-wound transformer in which a sheet conductor and an insulating film are wound in a layered manner, in which the sheet conductor is made of two or more types of conductors having different current densities. It is characterized by being constructed by overlapping the two.

(Function) According to the sheet-wound transformer of the present invention having the above configuration,
By configuring the sheet conductor by overlapping two or more types of conductors with different current densities, the thickness of the constituent conductors can be changed as appropriate depending on the current value required for the sheet-wound transformer and the thickness of the sheet conductor. You can respond accordingly.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIG. Incidentally, the same members as those of the conventional type shown in FIG. 4 are given the same reference numerals, and the description thereof will be omitted.

In this embodiment, as shown in FIG. 1, the sheet conductor 10 is a first sheet conductor 1 having a low current density but a wide width.
0a and a second sheet conductor 1 with a high current density but a narrow width.
0b.

Then, a plurality of narrow second sheet conductors 10b are arranged in parallel outside the wide first sheet conductor 10a so that they have approximately the same width.
0 is configured. Further, the sheet conductor 10 and the insulating film 1 are alternately wound to form a sheet-wound transformer.

An aluminum sheet is used as the first sheet conductor 10a, which has a low current density but a wide width, and a copper sheet is used as the second sheet conductor 10b, which has a high current density but a narrow width.

The sheet-wound transformer of this embodiment having such a configuration operates as described below. That is, the resistivity of the copper used as the narrow second sheet conductor 10b is about 1/3 that of the aluminum used as the wide first sheet conductor 10a, so the copper sheet is made of an aluminum sheet. It is possible to flow approximately three times the current. Moreover, this aluminum sheet allows the potentials of the plurality of copper sheets wound in parallel on the outside to be kept equal.

Then, by appropriately changing the thickness of the first sheet conductor 10a and the second sheet conductor 10b based on the current value required for the sheet-wound transformer and the thickness of the sheet conductor, the thickness of the entire sheet conductor is adjusted to a predetermined thickness. Since the current can be changed and a predetermined current can be obtained, the degree of freedom in designing the transformer can be increased.

Note that the present invention is not limited to the embodiments described above, and as shown in FIG. Wind the second sheet conductor 1 so that it protrudes.
The copper sheet with a high current density of 0b may be wound several cm apart from the end of the winding. In this case, the eddy current loss generated at the end of the winding can be reduced compared to the case where the copper sheet is wound together with the aluminum sheet up to the end of the winding. In this case, an insulator may be filled between the aluminum sheets protruding from the ends of the winding.

Furthermore, in the present invention, not only a copper sheet and an aluminum sheet are used in an overlapping manner, but also a copper sheet with a high current density may be covered with an aluminum sheet with a low current density, as shown in FIG. In this case, the thickness of the entire sheet conductor can be changed to a predetermined thickness, and not only can a predetermined current be obtained, but also the upper and lower ends of the winding can be coated with copper sheets. Eddy current loss generated at the wire ends can also be reduced.

Furthermore, the present invention can be constructed not only by using two types of sheet conductors having different current densities as described above, but also by appropriately combining a plurality of sheet conductors.

In addition, when two or more types of sheet conductors are appropriately stacked to form one sheet conductor, part or all of the stacked sheet conductors may be crimped, and then an insulating film may be stacked and wound. The winding may be constructed by overlapping all the constituent members from the beginning.

[Effects of the Invention] As explained above, according to the present invention, by configuring the sheet conductor by overlapping two or more types of conductors with different current densities, the current can be determined easily when designing a transformer. However, it is possible to provide a sheet-wound transformer in which the thickness of the sheet conductor can be changed as appropriate, and the degree of freedom in design can be increased.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a main part of an embodiment of a sheet-wound transformer according to the present invention, FIGS. 2 and 3 are enlarged cross-sectional views of main parts showing other embodiments of the present invention, and FIG. FIG. 2 is a cross-sectional view showing the main parts of a conventional sheet-wound transformer. 1... Insulating film, 2... Sheet conductor, 3...
Insulator, 10... Sheet conductor, 10a... First sheet conductor, 10b... Second sheet conductor.

Claims (1)

[Scope of Claims] A sheet-wound transformer formed by overlapping and winding a sheet conductor and an insulating film, characterized in that the sheet conductor is formed by overlapping two or more types of conductors having different current densities. sheet-wound transformer.