JP5247756B2 - Transformer for converter - Google Patents

Description

  The present invention relates to a transformer for a converter used for voltage and power conversion, and more particularly to a transformer for a converter used in an AC / DC conversion system.

  In an AC / DC conversion system that performs conversion between direct current and alternating current using a power converter such as an inverter, the voltage or The capacity is shared.

  A transformer for a converter used in an AC / DC conversion system excites an iron core by a DC side winding connected to the converter, and induces an AC voltage in the AC side winding. Moreover, in a transformer for a converter, it is common for a plurality of converters to have a parallel multi-winding configuration of a DC side winding connected to the converter, and a high voltage such as a frequency converter station. In a large-capacity system, an operation mode is used in which a plurality of transformers for converters are installed and the DC side windings of each transformer are connected in parallel and the AC side windings are connected in series.

  On the other hand, in a transformer for a converter used in a low-voltage medium- and small-capacity system for a distribution system such as a factory or a commercial facility, the transformer for the transformer can be configured as shown in FIG. Many.

  In other words, in FIG. 11, the transformer includes a magnetic iron core 5, DC side windings 2 and 3 wound around the outer periphery of the magnetic iron core 5, and an alternating current disposed on the outer circumference of the DC side windings 2 and 3. Side winding 1 is provided. The first DC side winding 2 and the second DC side winding 3 are respectively connected to different AC / DC converters. Further, a metal iron core abutment plate 4 is disposed outside the magnetic iron core 5 in order to hold the magnetic iron core 5.

  Further, at this time, in order to eliminate variations in excitation characteristics between the DC side windings 2 and 3 connected in parallel, the DC side windings 2 and 3 are configured as winding blocks having substantially the same dimensions. Arranged vertically.

  As a related technique, there is Patent Document 1.

JP-A-9-120919

  In an AC / DC conversion system, to prevent harmonic current generated by converter operation from flowing into the AC system, instead of using a harmonic elimination filter, multiple harmonic components are canceled out by multiple converters. A method of operating with multiple phases to fit may be taken.

  In the transformer for transformer disclosed in Patent Document 1, a plurality of DC side windings 2 and 3 are arranged in the vertical direction of the same iron core leg 5 to achieve a small size and light weight. During wave multiplex phase operation, harmonic currents 22 and 23 having opposite phases are applied to the DC side windings 2 and 3, respectively.

  Therefore, the harmonic leakage magnetic fluxes 32 and 33 generated around the DC side windings 2 and 3 are opposite to each other, but the DC side windings 2 and 3 are in the same direction and strengthen each other.

  As a result, almost all harmonic leakage magnetic flux generated in the DC side windings 2 and 3 is superimposed on the iron core plate 4 arranged facing the position between the DC side windings 2 and 3 and flows into the iron core abutment plate 4. As a result, a large eddy current is induced, resulting in problems such as increased loss and local overheating.

  In order to avoid this, the material of the iron core abutting plate 4 is changed to an insulator or a high-resistance conductor, or slit processing is performed, but there is a problem that both increase the cost.

  An object of the present invention is to provide a transformer for a converter capable of suppressing local overheating and reducing loss during harmonic multiple phase operation of the converter while suppressing an increase in cost of the transformer.

  In order to achieve the above object, a transformer for one phase of the present invention includes a magnetic iron core and a converter-side winding wound around the magnetic iron core, and a plurality of transformers that perform multi-phase operation. One converter side winding connected to an AC / DC converter and connected to one AC / DC converter is composed of a plurality of winding blocks, and a plurality of multiple phase operations are performed. The plurality of winding blocks of the plurality of converter-side windings connected to the AC / DC converter include a portion in which winding blocks connected to different AC / DC converters are arranged at positions adjacent to each other.

  A plurality of winding blocks are arranged in the radial direction and the vertical direction around the magnetic iron core, and the winding blocks adjacent to the radial direction and the vertical direction are separate from the converter to which the self-winding block is connected. Connected to the converter.

  Further, a plurality of winding blocks are arranged in a row in the radial direction around the magnetic core or in the vertical direction, and the winding blocks adjacent to the radial direction or the vertical direction are connected to the self-winding block. Is connected to another converter.

  In order to achieve the above object, a transformer for one phase of the present invention includes a magnetic iron core and a converter-side winding wound around the magnetic iron core, and a plurality of transformers that perform multi-phase operation. One converter-side winding connected to an AC / DC converter and connected to one AC / DC converter is composed of a plurality of winding blocks, and a plurality of AC / DC converters performing multi-phase operation. The number of winding blocks of the plurality of converter side windings connected to the DC converter is 6 or multiples thereof, and a plurality of winding blocks are arranged in the radial direction and the vertical direction around the magnetic core, and multiple phase operation is performed. The connection terminals of the winding blocks are externally connected in accordance with the number of multiplexing.

  Further, when externally connecting between the connection terminals of the winding blocks according to the number of multiplexing in the multiple phase operation, the plurality of winding blocks of the plurality of converter side windings are different from each other in the AC / DC. The part which arrange | positioned the winding block connected to the converter is included.

  As described above, according to the present invention, it is possible to obtain a transformer capable of suppressing local overheating and reducing loss during harmonic multiple phase operation without causing an increase in cost. Moreover, the leakage magnetic flux generated from the winding can be controlled only by changing the connection combination between the winding blocks.

The schematic longitudinal cross-sectional view for 1 phase of the transformer for transformers of the transformer by this invention. The figure which shows the connection relation of a transformer and an AC / DC converter. The figure which shows the condition of the harmonic leakage magnetic flux when two windings are arranged in series up and down. The figure which shows the condition of the harmonic leakage magnetic flux when two windings are divided into two and arranged vertically and horizontally. The figure which shows the example in a transformer connection when 2 times of converters are drive | operated. The figure which shows the example in a transformer connection when a converter carries out 3 multiplex operation. The figure which shows the example in a transformer connection when a converter carries out 6 multiplex operation. The figure which shows the other connection example in a transformer when 2 times of converters are drive | operated. The figure which shows the example of another connection in a transformer when 3 times of converters are drive | operated. The figure which shows the transformer structure which divided | segmented two windings into 2 and arranged in series up and down. The figure which shows the condition of the harmonic leakage magnetic flux when dividing two windings into two and arranging them vertically in series. The figure which shows the transformer structure which divided | segmented two windings into 2 and arranged in series on right and left. The figure which shows the condition of the harmonic leakage magnetic flux when two windings are divided into two and arranged in series on the left and right. The conventional longitudinal cross-sectional view for 1 phase of transformer for transformers of a transformer.

  Hereinafter, the present invention will be described with reference to the drawings.

  Hereinafter, an example of the transformer according to the present invention will be described based on a schematic cross-sectional view of one phase of the transformer for transformer shown in FIG.

  The transformer in this embodiment includes a magnetic iron core 5, a DC side winding group 10 wound around the outer periphery of the magnetic iron core 5, and an AC side winding 1 arranged on the outer periphery of the DC side winding group 10. And. The DC side winding group 10 includes a first DC side winding 12 and a second DC side winding 13, and the first DC side winding 12 and the second DC side winding 13 are configured. Are connected to different AC / DC converters. Further, a metal iron core abutment plate 4 is disposed outside the magnetic iron core 5 in order to hold the magnetic iron core 5.

  FIG. 2 is a diagram showing a connection relationship between the transformer of FIG. 1 and the AC / DC converter. FIG. 2 also shows a one-phase transformer transformer according to FIG. In this figure, the right side is provided with an AC side winding 1 on the AC system side. The left side is the converter side (DC power supply side), and includes a first DC side winding 12 and a second DC side winding 13 as the DC side winding group 10, and the first DC side. The winding 12 and the second DC side winding 13 are connected to different AC / DC converters 14 and 15, respectively. Note that the plurality of DC-side windings or the plurality of converters may be connected in series or in parallel. Further, although the number of windings and converters on the DC side is two in the figure, it can be increased.

  Here, an orthogonal conversion operation is performed in which the DC side winding group 10 is excited from the converter side (DC power supply side) and the AC side winding 1 generates AC power. Although the AC / DC conversion operation may be performed, the effect of the present invention is obtained when the converter side operates as the power source side (when the transformer is excited). It is assumed that this is done.

  The local overheating and loss increase of the transformer, which is a problem to be solved by the present invention, occurs when the converter is operated in multiple phases. Multiple phase operation of the converter means that two converters are operated in the same phase at the commercial frequency during excitation by the converter, but two converters are operated in reverse phase (180 degree delay) in the harmonics. This is an operation to cancel and take measures to prevent harmonics from appearing in the AC side winding 1. In addition, when performing multi-phase operation with three converters, they are operated with a 120-degree delay from each other. Although this operation has an effect that harmonics do not appear in the AC side winding 1, it causes a problem in the DC side winding group 10 of the transformer.

  In light of the above problems, the present invention is characterized in that the DC side winding 12 and the DC side winding 13 are each composed of a winding block group divided in the radial direction. That is, the DC side winding 12 is constituted by the winding blocks 2 a and 2 b having the winding block connecting terminals 6, and the DC side winding 13 is similarly formed by the winding block 3 a having the winding block connecting terminals 6. 3b respectively. And each is electrically connected in series via the connection block 6 between winding blocks.

  Thus, in the example of the figure, the DC side winding 12 and the DC side winding 13 are each constituted by two pieces, and are constituted by a total of four winding blocks. In addition, in the DC side windings 12 and 13, the vertical positional relationship between the winding block 2a and the winding block 3a disposed on the inner peripheral side, and the vertical positional relationship between the winding blocks 2b and 3b disposed on the outer peripheral side. Arrange and connect each winding block so that is reversed. This prevents the winding blocks belonging to the same DC side winding from being arranged adjacent to each other in the vertical direction and the radial direction.

  FIG. 1 shows that harmonic currents 22a, 22b and 23a having opposite phases are respectively applied to the DC side windings 12 and 13 so that the harmonic current generated on the converter side in the AC / DC conversion system does not transfer to the AC side winding 1. , 23b are applied (multi-phase operation with two converters, and therefore the harmonics are in reverse phase). Harmonic leakage magnetic fluxes 32a, 32b and 33a, 33b are generated in the directions of the arrows around the winding blocks 2a, 2b and 3a, 3b.

  FIG. 3 is a diagram showing the situation of harmonic leakage magnetic flux due to the winding arrangement. FIG. 3A shows a state where the DC side winding 12 and the DC side winding 13 are arranged vertically without being divided, and FIG. The harmonic leakage magnetic flux when it is set as the four winding block arrangement | positioning of FIG.

  If the harmonic leakage magnetic fluxes generated by the DC side winding 12 and the DC side winding 13 are 2 respectively when they are arranged vertically without being divided (FIG. 3A), the winding adjacent portions Then, it turns out that the harmonic leakage magnetic flux concentration of the magnitude | size of 4 arises. On the other hand, the harmonic leakage magnetic flux in the divided winding of FIG. 3B divides the DC side winding 12 and the DC side winding 13 into two, so that the harmonics from one winding block. It can be seen that the leakage flux has a magnitude of 1, and thus a harmonic leakage flux concentration of magnitude 2 occurs in the adjacent portion of the winding.

  As described above, according to the present invention, the harmonic leakage magnetic fluxes 32a and 32b generated around the winding blocks 2a and 2b are approximately ½ of the case where the winding blocks 2a and 2b are arranged adjacent to each other. The same applies to the harmonic leakage magnetic fluxes 13a and 13b generated around the winding blocks 3a and 3b.

  Thereby, the amount of harmonic leakage magnetic flux concentrated between the DC side windings 12 and 13 is also about 1 when the winding blocks 2a and 2b and the winding blocks 3a and 3b are arranged adjacent to each other. Relaxed to a size of / 2.

  The amount of harmonic leakage magnetic flux concentrated between the DC side windings 12 and 13 is about ½, so that the harmonics generated in the iron core plate 4 and the AC side winding 1 into which the harmonic leakage magnetic flux flows. The eddy current also becomes about ½, and as a result, the harmonic stray loss generated in the iron core plate 4 and the AC side winding 1 is reduced to about ¼.

  In the embodiment of FIG. 1, the winding blocks 2a and 2b constituting the DC side winding 12 and the winding blocks 3a and 3b constituting the DC side winding 13 are respectively connected in series. However, the same effect can be obtained even in the case of parallel connection.

  Further, by making the winding blocks 2a and 3a and the winding blocks 2b and 3b have the same size and shape, only the connection state of the connection terminals between the winding blocks is changed without changing the arrangement of the winding blocks. Thus, it is possible to arbitrarily change whether or not the winding blocks belonging to the same DC side winding are arranged adjacently, and further whether the winding blocks are connected in series or in parallel.

  Further, the gap between the inner diameter side winding blocks 2a and 3a and the outer diameter side winding blocks 2b and 3b can also serve as a flow path for the insulating cooling medium, improving the cooling efficiency of the winding and increasing the temperature. The rise can be suppressed.

  Furthermore, in the first embodiment, the DC side windings 12 and 13 are each divided into two winding blocks. However, further loss reduction effect can be achieved by dividing the windings into more winding blocks. Can be obtained.

  Further, the same effect can be obtained even when the iron core abutting plate 4 is not made of metal or when the iron core abutting plate 4 itself is not present.

  As described above, according to the present invention, it is possible to alleviate the concentration of the harmonic leakage magnetic flux between the two windings when the anti-phase harmonic current is applied to the DC side windings 12 and 13. . As a result, the material of the iron core abutment plate 4 does not need to be an insulator or a high-resistance conductor, suppresses local overheating, and significantly reduces harmonic stray loss without taking a costly measure such as slitting. It becomes possible.

  The effects of the present invention described above are achieved by preventing the winding blocks belonging to the same DC side winding from being arranged adjacent to each other in the vertical direction and the radial direction, but are simply divided into four blocks. So this effect cannot be achieved.

  For example, when two winding blocks of winding 2 on the inner side and winding 3 on the outer side are arranged two by two, it is the same as in the case of non-dividing, and instead of causing magnetic flux concentration to the iron core side, up and down The leakage flux is the same as in the case of non-dividing, and the effect of dividing cannot be obtained. Further, when the winding 2 and the winding 3 are arranged in the radial direction, it is assumed that it is difficult to make the impedance and the like the same.

  Next, in manufacturing the transformer of the present invention, it will be described that the transformer is configured in consideration of the circumstances of the converter connected to the transformer and used. Here, the situation on the converter side means that, in the operation of the converter, it is possible to carry out 2-multiplex, 3-multiplex, and 6-multiplex operations. On the transformer side, When changing the operation mode, it is desirable not to prepare a product each time but to deal with it as standard.

  4, 5 and 6 are schematic cross-sectional views of one phase of a transformer for a transformer, showing a configuration example of a transformer according to the present invention which can cope with this problem as standard.

  In this embodiment, in the embodiment shown in FIG. 1, the winding block is made up of 6 blocks of 7a, 7b, 7c, 7d, 7e, and 7f, so that the converters are operated in 2 multiplex, 3 multiplex, 6 multiplex operations. On the other hand, a state is shown in which it is possible to cope only by changing the electrical connection of the inter-winding block connection terminals 6. Therefore, when manufacturing a transformer, a transformer having the configuration shown in FIG. 6 is typically manufactured, and when the multiple operation mode of the converter is determined, one of the connections shown in FIGS. Standardization is possible by deciding and executing the connection externally.

  Of these connections, FIG. 4 shows an example of the connection between winding blocks for double multiplex operation of the converter. The winding blocks 7a, 7e and 7c are connected to the one converter side. 7d, 7b, 7f are connected and connected to the other converter side. Here, as for the position of the connection terminal 6 shown in the winding block 7, the side close to the iron core 5 starts winding, and the side far from the iron core 5 shows the end of winding.

  Here, an example is shown in which the winding blocks are connected so that all the winding blocks connected to the same converter are not adjacent to each other. However, as shown in FIG. 7, the winding blocks 7a and 7e are connected. , 7f connected to one converter side, winding blocks 7d, 7b, 7c connected to the other converter side, etc. Even in this case, the leakage magnetic flux flowing into the iron core abutment plate 4 can be reduced, and stray loss generated in the iron core abutment plate 4 can be reduced.

  FIG. 5 shows an example of connection between winding blocks for the converter 3 multiplex operation. The winding blocks 7a and 7f are connected and the winding blocks 7d and 7c are connected to the first converter side. Winding blocks 7b and 7e are connected to the second converter side and connected to the third converter side. In this case, the winding blocks 7d and 7c of the portion connected to the second converter side by connecting the winding blocks 7d and 7c are in a vertical relationship, but other portions are adjacent to each other. The effect of the present invention is achieved.

  In addition, in the case of the converter 3 multiplex operation, in addition to the combination of connections between winding blocks shown here, any combination of connections between winding blocks is possible. For example, in order not to make all the windings adjacent to each other, as shown in FIG. 8, the winding blocks 7a and 7e are connected and the winding blocks 7b and 7e are connected to the first converter side. It is conceivable to connect the winding blocks 7c and 7a to the second converter side and connect to the third converter side.

  FIG. 6 shows an example of the connection between the winding blocks for the converter 6 multiplex operation, and the winding blocks 7a, 7b, 7c, 7d, 7e, and 7f are not connected to each other and are different from each other. Connected to the converter side.

  In this way, by setting the number of winding blocks equal to the common multiple of the assumed number of converters, even after the installation of the transformer, changes in operating conditions on the converter side, changes in the number of multiplexing, etc. However, it is possible to cope with this by simply changing the connection state between the winding blocks.

  In the embodiment shown in FIG. 1 described above, the winding 2 and the winding 3 are each divided into two, and a total of 4 winding blocks are configured as row / column 2 winding blocks, which are adjacent to the top and bottom or left and right positions. The winding block is made of different windings. Further, in the embodiment of FIGS. 4 to 8, a total of 6 winding blocks are configured in 2 rows and 3 columns, and winding blocks adjacent to the top and bottom or left and right positions are connected to different converters as much as possible. .

  The configurations described above all have the winding blocks in the left / right / up / down relationship. However, in other embodiments of the present invention, multiple winding blocks can be arranged vertically or left / right to provide higher harmonics. Reduce the concentration of magnetic flux leakage.

  FIG. 9 shows an embodiment of the present invention in which a plurality of winding blocks are vertically arranged. In this example, the winding blocks obtained by dividing the winding 2 and the winding 3 are sequentially arranged in the order of 2a, 3a, 2b, 3b from the top as shown in FIG. 9A. FIG. 9B is a diagram showing the state of magnetic flux concentration at this time, and the magnetic flux concentrated between the winding blocks is 2 in the same manner as in FIG. It can be seen that is relaxed.

  FIG. 10 shows an embodiment of the present invention in which a plurality of winding blocks are arranged one above the other. In this example, the winding blocks obtained by dividing the winding 2 and the winding 3 are sequentially arranged in the order of 2a, 3a, 2b, 3b from the left as shown in FIG. 10 (a). FIG. 10B is a diagram showing the state of magnetic flux concentration at this time. In this case, the direction of the magnetic flux concentration is not the direction of the iron core abutment plate 4 but up and down. Except for this point, the magnetic flux concentrated between the winding blocks is the same as in the case of FIG. Since the size is 2, it can be seen that the concentration is relaxed.

  The above description has been given by way of example of a transformer for a converter in which an AC side winding is arranged on the outer peripheral side of the DC side winding. However, the present invention is not limited to this, and the DC side is connected to the outer peripheral side of the AC side winding. The present invention can also be applied to a transformer for a transformer in which windings are arranged and a transformer for normal power or distribution.

  The above explanation has been given by taking an example of a transformer for a converter used in a power distribution system. However, the present invention is also applicable to a transformer for a converter used in an AC / DC conversion system, and also to a transformer for a substation or a power distribution in general. Can be applied.

DESCRIPTION OF SYMBOLS 1 ... AC side winding 2, 3 ... DC side winding 4 ... Iron core abutment plate 5 ... Magnetic iron core 6 ... Interwinding block connection terminal 10 ... DC side winding group 12, 13 ... DC side winding 2a, 2b, 3a, 3b... Winding blocks 7a to 7f constituting the DC side winding group. Winding blocks 22 and 23 constituting the DC side winding group. Harmonic currents 22a, 22b, 23a and 23b flowing in the DC side winding. ... Harmonic currents 32a, 32b, 33a, 33b flowing through the winding block ... Harmonic leakage magnetic flux generated around the winding block.

Claims (4)

Transformer for one phase of converter comprising a magnetic iron core and a converter-side winding wound around the magnetic iron core and used by being connected to a plurality of AC / DC converters that perform multi-phase operation The one converter-side winding connected to the one AC / DC converter is composed of a plurality of winding blocks, and a plurality of AC / DC conversions that perform the multi-phase operation. The plurality of winding blocks of the plurality of converter-side windings connected to the converter are connected to different AC / DC converters in a phase relationship in which at least one harmonic component cancels each other at positions adjacent to each other. A transformer for a converter characterized by including a portion where a winding block is disposed. The transformer for a converter according to claim 1,
The plurality of winding blocks are arranged in the radial direction and the vertical direction around the magnetic iron core, and the winding block adjacent to the radial direction and the vertical direction is the converter to which the self-winding block is connected. A converter transformer, wherein at least one higher harmonic component is connected to a converter having a phase opposite to that of the converter. The transformer for a converter according to claim 1,
The plurality of winding blocks are arranged in a row in the radial direction or the vertical direction around the magnetic iron core, and the winding blocks adjacent to the radial direction or the vertical direction are connected to the self-winding block. A transformer for converter, characterized in that at least one harmonic component different from the transformer is connected to a converter having a phase opposite to that of the converter. In the transformer for a converter according to any one of claims 1 to 3,
The number of winding blocks of the plurality of converter-side windings connected to the plurality of AC / DC converters performing the multi-phase operation is 6 or a multiple thereof, and the winding block is a radial direction around the magnetic iron core. A transformer for a converter, wherein a plurality of coils are arranged in the vertical direction, and the connection terminals of the winding blocks are externally connected in accordance with the number of multiplexed phases.

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