JPH0653060A - Transformer for converter - Google Patents

Abstract

PURPOSE:To enable the unbalanced three phase voltage to be avoided by arranging triangular connected windings inside and outside as if holding a star connected windings. CONSTITUTION:The primary windings 1a, 2a, 3a and the secondary windings 1b, 2b, 3b are wound around respective main legs 5-7 taking concentrical circular shape. The primary windings 1a, 2a, 3a are triangular connected while the secondary windings 1b, 2b, 3b are star connected. Next, the tertiary windings 1c, 2c, 3c wound around outside the secondary windings 1b, 2b, 3b are triangular connected. Through these procedures, the zero phase fluxing can be suppressed by the windings triangular connected inside and outside thereby enabling the unbalanced three phase voltage to be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer for a converter.

[0002]

2. Description of the Related Art Conventionally, a three-phase transformer has an iron core and winding structure as shown in Japanese Patent Application Laid-Open No. 53-42318. Further, as a three-phase wiring, Japanese Patent Laid-Open No.
As shown in Japanese Patent Publication No. 3-28226, there are a plurality of star-shaped windings and one triangular winding. As a usage method, there is a method in which one winding is connected to a power source such as a system and the remaining windings are connected to a converter as shown in JP-A-53-28226. Furthermore, as shown in JP-A-53-29525,
There is a combination in which a plurality of transformers for converters are connected in parallel and used.

[0003]

As shown in the above-described winding configuration example, when one triangular connection winding is arranged for a plurality of star connection windings, the star connection winding is zero. When the phase voltage component is included, it is not possible to sufficiently suppress the generation of zero-phase magnetic flux in the iron core with only one triangular connection winding, which causes the problem of the three-phase voltage unbalance phenomenon.

Generally, the triangular connection winding has an effect of suppressing the generation of zero-phase magnetic flux, but when an iron core structure other than the three-phase three-leg core structure is used, the generation of zero-phase magnetic flux is suppressed over the entire iron core region. It is not possible. For example, in a two-winding transformer with a three-phase five-leg iron core, a triangle connection winding from the iron core main leg side,
When arranged in the order of star-shaped windings, the generation of zero-phase magnetic flux of the main leg around which the triangle-shaped windings are wound is suppressed, but the five-leg iron core facing the star-shaped windings is suppressed. Since the zero-phase magnetic flux generated in the side leg is not suppressed, a three-phase voltage imbalance occurs.

The present invention has been made in view of the above points, and an object of the present invention is to provide a transformer for a converter capable of preventing the occurrence of three-phase voltage imbalance.

[0006]

The above object is achieved by arranging the windings which are connected in a triangle inside and outside so as to sandwich the windings which are connected in a star shape.

[0007]

Since the above means is provided, the generation of zero-phase magnetic flux can be suppressed by the triangular connection windings arranged inside and outside.

[0008]

EXAMPLES Next, the present invention will be specifically described with reference to Examples.

[Embodiment 1] FIG. 1 shows an embodiment of the present invention. A transformer transformer comprising a three-phase transformer having at least one star-connected winding (secondary winding) 1b, 2b, 3b, in this embodiment a star-connected winding 1b, Windings (primary winding, tertiary winding) 1a which are triangularly connected to the inside and outside so as to sandwich 2b and 3b,
2a, 3a, 1c, 2c and 3c are arranged. By doing so, the generation of zero-phase magnetic flux is suppressed by the triangular connection windings 1a, 2a, 3a, 1c, 2c, 3c arranged inside and outside, and the unbalance of the three-phase voltage is caused. It is possible to obtain a transformer for a converter capable of preventing the occurrence of

That is, FIG. 1 is a structural diagram of a transformer for a converter having a winding arrangement according to this embodiment. In the figure, the transformer for the converter is a three-phase transformer, and the iron core 4 is a three-phase five-legged structure including main legs 5 to 7 around which the winding is wound and side legs 8 and 9 on which the winding is not wound. It is an iron core. A primary winding 1a, 2a, 3a and a secondary winding 1b, 2b, 3b are wound around each main leg 5-7 concentrically with respect to each main leg 5-7. In this embodiment, the primary windings 1a, 2a and 3a are connected in a triangular shape, and the secondary windings 1b, 2b and 3b are connected in a star shape.

The tertiary windings 1c, 2c and 3c are windings arranged according to the present embodiment, and are wound concentrically outside the star-connected secondary windings 1b, 2b and 3b to form a tertiary winding. The windings 1c, 2c and 3c are connected in a triangular shape.

The primary windings 1a, 2a, 3a are connected to a converter which is a three-phase power source, and the secondary windings 1b, 2b, 3b are connected.
Is connected to a separate three-phase power supply. Tertiary winding 1
c, 2c and 3c are connected in a triangle inside the transformer.

The effect of suppressing the generation of zero-phase magnetic flux in the iron core leg by the winding arrangement of this embodiment will be described below.

FIG. 2 is a diagram showing the flow of magnetic flux flowing through the main leg 5 and the side legs 8 of the three-phase five-leg iron core 4, and one leg portion in FIG. 1 shows one phase. In the figure, the primary winding 1a is connected to the primary windings 2a and 3a (see FIG. 1) of other phases in a triangular manner, so that the primary winding voltages V1a and V2 of each phase are connected.
The sum of a and V3a is V1a + V2a + V3a = 0.
Therefore, there is no zero-phase component of the main leg magnetic flux 5F, and the generation of zero-phase magnetic flux is suppressed. On the other hand, the secondary winding 1b is the secondary winding 2 of the other phase.
b and 3b (see FIG. 1) are connected in a star shape, the secondary winding voltage V1b,
The sum of V2b and V3b does not become zero, that is, V1b +
In some cases, V2b + V3b ≠ 0. At this time, the zero-phase magnetic flux 8F is generated in the side leg 8 of the three-phase five-leg iron core and tries to flow in the iron core.

However, in the winding arrangement of this embodiment,
Outside the star-shaped connection winding 1b, there is a tertiary winding 1c which is triangularly connected to the tertiary winding of another phase. The sum of the voltages V1c, V2c and V3c generated in each phase winding of the tertiary winding is V1c + V2c + V3c = 0 as in the case of the primary winding that is connected in a triangular shape. This means that the zero-phase magnetic flux 8F flowing through the side leg 8 facing the tertiary winding 1c is not generated. Therefore, when the tertiary windings to be connected in a triangular configuration are arranged outside the star connection windings, the generation of the zero-phase magnetic flux 5F in the main landing gear is suppressed by the inner-side triangular connection winding 1a, and the outer-side triangular connection winding 1c is also suppressed.
As a result, the generation of the zero-phase magnetic flux 8F in the side leg is suppressed.

That is, the sum of the voltages of the secondary windings that are star-connected is V1b + V2b + V3b = 0, and imbalance is suppressed.

[Embodiment 2] FIG. 3 shows another embodiment of the present invention. This figure is a diagram showing a configuration example of a conversion device using a converter transformer having a winding arrangement. The converter comprises transformer transformers 11 to 14, and the transformers 11 and 12 are transformers having the structure of FIG. 1 according to this embodiment. The primary windings 11A to 14A of each transformer are respectively connected to the independent converters 15 to 18, and the secondary windings 11B to 14A are connected.
B is connected in series to the system 19. In the figure, 10 is a combination main body of a transformer for a converter, and 11c and 12c are tertiary windings.

FIG. 4 is a detailed connection diagram of the transformer for each converter shown in FIG. Primary winding 11 of transformer for each converter
A, 12A, 13A, 14A phase windings 11A each
u, 11Av, 11Aw, 12Au, 12Av, 12A
w, 13Au, 13Av, 13Aw, 14Au, 14A
Assuming that v and 14 Aw, they are connected in a triangular manner as shown in FIG. Secondary winding 1
11 windings for each phase of 1B, 12B, 13B, 14B
Bu, 11Bv, 11Bw, 12Bu, 12Bv, 12
Bw, 13Bu, 13Bv, 13Bw, 14Bu, 14
Bv, 14Bw, 13Bu, 14Bu, 13B
v, 14Bv, 13Bw, 14Bw form a triangular connection connected in series with each other, and 11Bu and 12Bu, 11B
v and 12Bv, 11Bw and 12Bw are respectively connected in series and connected to each phase of the windings which are connected in a triangle, and the secondary winding as a whole has the connection shown in FIG. The tertiary windings 11c and 12c according to the present embodiment have 11 windings of each phase.
Cu, 12Cv, 11Cw, 12Cu, 12Cv, 12
If it is Cw, it is connected in a triangle as shown in FIG. Further, the relative relationship between each phase winding of each primary winding and each phase winding of each tertiary winding and each phase winding of the secondary winding is as shown in FIG. It corresponds.

According to this application example, the imbalance of the three-phase voltage of the secondary windings of the transformer transformers 11 and 12 having the star-shaped connection is suppressed, so that the case of multiple series connection as shown in FIG. However, the balance of the three-phase voltage is maintained.

As described above, according to this embodiment, since the winding arrangement as shown in FIG. 1 is provided, it has an effect of suppressing the generation of zero-phase magnetic flux in the iron core, and the windings are star-connected. It is possible to stabilize the balance of the three-phase voltage of the line.

[0021]

As described above, according to the present invention, since the windings that are connected in a triangular shape are arranged inside and outside so as to sandwich the windings that are connected in a star shape, the windings that are arranged inside and outside are connected in a triangular shape. Generation of zero-phase magnetic flux is suppressed by the line,
It is possible to obtain a transformer for a converter capable of preventing the occurrence of three-phase voltage imbalance.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a winding arrangement of an embodiment of a transformer for a converter of the present invention.

FIG. 2 is an explanatory diagram showing an effect of one embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an overall configuration of a conversion device of another embodiment of the converter transformer of the present invention.

FIG. 4 shows mutual connections of the transformers for converters shown in FIG. 3, where (a) is a connection diagram showing the connection of the entire secondary winding, and (b) each converter has a triangular connection of the primary winding. Connection diagram, which is connected to
(C) It is a connection diagram in which the tertiary winding is connected in a triangular shape.

[Explanation of symbols]

1a to 3a ... Primary winding (triangular connection), 1b to 3b
… Secondary winding (star connection), 1c to 3c… Tertiary winding (triangular connection), 4… Three-phase five-leg iron core, 5 to 7… Iron core main leg, 8, 9… Iron core side leg 11-14 ... Transformer for converter, 15-18 ... Converter.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shizuo Ichise 1-1-1, Kokubun-cho, Hitachi-shi, Ibaraki Hitachi Kokubun Plant, Ltd.

Claims (2)

[Claims] 1. A transformer transformer comprising a three-phase transformer having at least one star connected winding.
A transformer transformer, wherein windings that are connected in a triangular shape are arranged inside and outside so as to sandwich the windings that are connected in a star shape. 2. A three-phase transformer in which a plurality of star-shaped windings are concentrically arranged, and a triangle-connected winding is arranged inside the innermost star-shaped winding. The transformer transformer according to claim 1, wherein the windings that are connected in a triangular shape are arranged outside the outermost windings that are connected in a star shape.