JP2001169566A - Transformer for converter of ac-dc converter system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transformer for a converter of an AC-DC converter system capable of facilitating transportation to reduce the transportation cost, by averaging the sizes of the profiles of the transformers for the converters of respective stages and reducing the profiles of the transformers. SOLUTION: The secondary windings 2A to 2D of the transformers for the converters of the order of lower potentials are arranged to the primary windings 3 of the transformers for the converters connected in series of the order of higher potentials. That is, the primary winding 3A of the transformer of the highest potential corresponds to the secondary winding 2A of the transformer of the lowest potential, while the primary winding 3D of the transformer of the lowest potential corresponds to the secondary winding 2D of the transformer of the highest potential.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer for an AC / DC converter in which AC outputs of a plurality of unit converters are connected in series by a transformer and DC outputs are connected in series. .

[0002]

2. Description of the Related Art Generally, when a DC power supply is connected to an AC system, an AC / DC converter is employed. This AC / DC converter includes a plurality of unit converters connected in multiple stages in series, and a converter transformer having a primary winding and a secondary winding. Here, the main circuit configuration of the AC / DC converter will be specifically described with reference to FIG. Note that the number of serial stages of the unit converter can be any number according to the specification, but in FIG. 4, the number of serial stages is expressed as four.

As shown in FIG. 4, a ground circuit 5 is connected to a DC power supply 4, and unit converters 1A to 1D are connected in four stages in series. These unit converters 1A to 1D
Is constructed by connecting a plurality of self-extinguishing switching elements in a bridge. Converter secondary windings 2A to 2D are connected to the AC outputs of unit converters 1A to 1D, respectively, and corresponding to converter secondary windings 2A to 2D of each stage, the Y-connection is made. A configured transformer primary winding 3 is provided. Transformer primary winding 3 is composed of series-connected primary windings 3A to 3D.

In the above-described AC / DC converter, the AC voltage outputs of the unit converters 1A to 1D at each stage appear as voltages of the converter secondary windings 2A to 2D at each stage. It appears in each stage primary winding 3A-3D. As described above, since the primary windings 3A to 3D of the respective stages are connected in series, the AC voltage outputs of the AC / DC converter are added and appear in the transformer primary winding 3 for the converter.

FIG. 5 is a schematic external view of a transformer for a converter used in the AC / DC converter of FIG. In FIG. 5, 6A
To 6D are transformer main bodies for each stage, 7A to 7C are connection circuits for serially connecting the primary windings 3A to 3D at each stage, 8
Is a primary side bushing, and 9A to 9D are secondary side bushings. At this time, the insulation class of the connection circuits 7A to 7C and the secondary side bushings 9A to 9D is 7A, 7B,
7C, 9A, 9B, 9C, and 9D, and the sizes of the connection circuits 7A to 7C and the secondary bushings 9A to 9D correspond to this order.

[0006]

In the above prior art, the primary winding 3A of the transformer for the converter having the highest potential is used.
Corresponds to the transformer secondary winding 2D having the highest potential, and the transformer primary winding 3D having the lowest potential corresponds to the transformer secondary winding 2A having the lowest potential. The level of the potential is the level of the insulation class, and the higher the potential, the larger the outer shape to secure insulation. Therefore, the larger the outer shape of the primary winding 3 is, the larger the outer shape of the secondary windings 2A to 2D is, and the transformer main bodies 6A to 6D for the converter as shown in FIG.
The size of the outer shape of 6A is the largest, and hereinafter, 6B,
6C, 6D.

That is, in the prior art, the transformer main body connected to the unit converter at the high voltage stage is larger than the transformer main body connected to the unit converter at the low voltage stage. The size of the vessel body varied.
In recent years, the number of stages of unit converters has tended to increase with the increase in capacity of AC / DC converters, and the variation in the size of converter transformers has widened. For this reason, the outer shape of the largest transformer for a converter has become large, and transportation has become difficult, resulting in an increase in transportation costs.

The present invention has been proposed to solve the above-mentioned problems, and an object of the present invention is to average the size of the outer shape of the transformer for each stage and reduce the outer shape of the transformer for the converter. Accordingly, it is an object of the present invention to provide a transformer for a converter of an AC / DC converter that can facilitate transportation and reduce transportation costs.

[0009]

In order to achieve the above object, the present invention relates to a plurality of unit converters each having a plurality of self-extinguishing type switching elements connected in a bridge and connected in series in a multistage manner. The AC output of the transformer is connected to the transformer secondary winding for the converter, and the transformer primary winding for each converter is connected in series and connected to the AC system.
The transformer for a converter has the following technical features.

According to the first aspect of the present invention, the voltage applied to the primary winding having the highest potential appears on the secondary winding having the lowest potential as a voltage corresponding to the transformation ratio. It is characterized in that the secondary windings in the order of lower potential correspond to each other. According to the first aspect of the present invention, a transformer for one stage is configured by combining a primary winding having a high insulation class and a secondary winding having a low insulation class, and the primary winding has a low insulation class. A transformer for one stage can be configured by combining a wire and a secondary winding with a high insulation class. Therefore, the size of the outer shape of the transformer main body in each stage can be averaged, and the outer shape of the transformer main body, which is the largest as compared with the related art, can be reduced. Thereby, the transportation of the transformer main body for the converter is facilitated, and the transportation cost can be reduced.

According to a second aspect of the present invention, in the transformer for an AC / DC converter according to the first aspect, a primary winding of each of the transformers for the converter is constituted by a Y-connection. According to the second aspect of the present invention, the same effect as that of the first aspect of the invention can be exerted in a transformer for a converter in which the primary winding is formed by Y connection.

According to a third aspect of the present invention, in the transformer for a converter of the AC / DC converter according to the first aspect, the primary winding of each transformer for the converter is configured by a combination of a Y connection and a Δ connection. And According to the third aspect of the present invention, in a transformer for a converter in which a primary winding is configured by a combination of a Y-connection and a Δ-connection, the same operation and effect as those of the first aspect of the invention can be exhibited. it can.

According to a fourth aspect of the present invention, in the transformer for an AC / DC converter according to the first aspect, the primary winding of each transformer for the converter is formed by a staggered connection. According to the fourth aspect of the present invention, in a transformer for a converter in which the primary winding is formed in a staggered connection, the same function and effect as the first aspect of the present invention can be exhibited.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to FIGS. 1 to 3, the same reference numerals are given to the components having the same functions as those in FIG. (1) First Embodiment [Configuration] The first embodiment corresponds to the second aspect of the present invention, and FIG. 1 is a configuration diagram of the first embodiment.
The feature of the configuration of the first embodiment is that the transformer primary windings 3A to 3D constituting the Y-connection correspond to the transformer secondary windings 2A to 2D, respectively. That is, the voltage applied to the primary winding 3A having the highest potential appears on the secondary winding 2A having the lowest potential as a voltage corresponding to the transformation ratio. Are configured to correspond.

More specifically, the transformer primary winding 3A having the highest potential corresponds to the transformer secondary winding 2A having the lowest potential, and the transformer primary primary having the second highest potential. The winding 3B corresponds to the second lowest potential transformer secondary winding 2B, and the third highest potential transformer primary winding 3C has the third lowest potential transformer secondary. The transformer primary winding 3D having the fourth highest potential, ie, the lowest potential, corresponds to the winding 2C, and the transformer secondary winding 2D having the fourth lowest potential, ie, the highest potential. Corresponding to

[Operation and Effect] In the first embodiment having the above configuration, the larger the outer shape is on the primary winding 3 side, the smaller the outer shape is on the secondary windings 2A to 2D side. It has become. Therefore, there is no variation in the size of the outer shape of the transformer main body in each stage, and the size of the outer shape can be averaged. Therefore, it is possible to reduce the maximum outer shape of the transformer main body. Thereby, the transformer main body for the converter can be easily transported, which can contribute to a reduction in transportation costs.

(2) Second Embodiment [Configuration] A second embodiment corresponds to the third aspect of the present invention, and FIG. 2 is a configuration diagram of the second embodiment.
The second embodiment is characterized in that the primary winding 3 of the transformer for a converter is constituted by a combination of a Y connection and a Δ connection, and the other parts are the same as those of the first embodiment. . That is, the transformer primary winding 3A with the highest potential corresponds to the transformer secondary winding 2A with the lowest potential, and conversely, the transformer primary windings 3D and 3C with the lowest potential are Transformer secondary winding 2D having the highest potential and transformer secondary winding 2D having the second highest potential
C.

[Operation and Effect] According to the above-described second embodiment, in the transformer for a converter in which the primary winding 3 is configured by combining the Y-connection and the Δ-connection, As in the embodiment, the transformer main body for the converter can be reduced in size, and the transportation cost can be reduced.

(3) Third Embodiment [Configuration] A third embodiment corresponds to the invention of claim 4, and FIG. 3 is a configuration diagram of the third embodiment.
The third embodiment is characterized in that the transformer primary winding 3 for the converter is formed by a staggered connection, and the other parts are the same as those of the first and second embodiments. That is,
The transformer primary winding 3A having the highest potential corresponds to the transformer secondary winding 2A having the lowest potential, and conversely, the transformer primary windings 3D and 3C having the lowest potential have the highest potential. , And a converter secondary winding 2C having the second highest potential.

[Operation and Effect] According to the above-described third embodiment, a transformer for a converter in which the primary winding 3 is formed in a staggered connection is different from the first and second embodiments. Similarly, the transformer main body for the converter can be downsized, and the transportation cost can be reduced.

[0021]

As described above, according to the transformer for a converter of an AC / DC converter according to the present invention, conversion is performed in the order of higher potential in the order of higher potential of the primary winding of the transformer connected in series. Corresponding secondary transformers for transformers make it possible to average the size of the outer shape of the transformer for each stage and reduce the maximum outer shape of the transformer for the transformer. Can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a transformer for a converter of a conventional AC / DC converter.

FIG. 5 is a schematic external view of a transformer for a converter used in the AC / DC converter of FIG. 4;

[Explanation of symbols]

 1A to 1D: Unit converter 2A to 2D: Transformer secondary winding for converter 3 ... Transformer primary winding 3A to 3D: Transformer transformer primary winding for each stage 4: DC power supply 5: Grounding circuit 6A -6D ... Transformer main body for converter 7A-7C-Primary winding series connection circuit 8-Primary side bushing 9A-9D-Secondary side bushing

Claims (4)

[Claims] 1. A plurality of unit converters each having a plurality of self-extinguishing type switching elements connected in a bridge configuration are connected in multiple stages in series, and the AC outputs of the plurality of unit converters are connected to a secondary winding of a transformer for a converter. In an AC / DC converter in which the primary windings of each transformer are connected in series and connected to an AC system, the voltage applied to the primary winding with the highest potential is transformed into the secondary winding with the lowest potential. A transformer for an AC / DC converter, wherein a secondary winding which appears as a voltage corresponding to a ratio and has a lower potential corresponds to a primary winding having a higher potential. 2. The transformer for an AC / DC converter according to claim 1, wherein the primary winding of the transformer for the converter comprises a Y connection. 3. The transformer for a converter of an AC / DC converter according to claim 1, wherein the primary winding of the transformer for the converter is constituted by a connection obtained by combining a Y connection and a Δ connection. 4. The transformer for an AC / DC converter according to claim 1, wherein the primary winding of the transformer for the converter is formed in a staggered connection.