JPH06333754A - Transformer for cycloconverter - Google Patents

Abstract

PURPOSE:To provide a transformer with equal factors of resistance and leakage reactance in positive and negative group windings. CONSTITUTION:In a first constitution, a conductor L15 in a positive group winding 15 and a conductor L16 in a negative group winding 16 are turned double in an axial direction on a core leg 14 at the same time. In a second constitution, the positive group winding 15 and the negative group winding 16 are put on separated divisions in an axial direction of the core leg 14. Then, a power-supply winding 17 is split into two and they are mounted around each outer boundary of the positive and negative group windings 15 and 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cycloconverter transformer suitable for use as a power source for a circulating current type cycloconverter.

[0002]

2. Description of the Related Art A conventional structure of a circulating current type cycloconverter using a transformer of this type will be described with reference to FIG.
In this figure, 1 is a three-phase AC power supply, 2 is a three-phase transformer consisting of a power supply winding (primary winding) 3, a positive group winding 4 and a negative group winding 5 (all are secondary windings), Reference numeral 6 is a positive group converter in which a thyristor 7 is connected in a three-phase bridge, 8 is a negative group converter in which a thyristor 9 is connected in a three-phase bridge, 10
Reference numerals and 11 are circulating current limiting reactors connected between the positive and negative DC output terminals of both converters 6 and 8, and 12 is a load connected between the neutral points of both reactors 10 and 11.

In such a cycloconverter,
When a gate signal of a predetermined pattern is given to the gates of the thyristors 7 and 9 of each converter 6 and 8, the positive group converter 6
Between the output terminals of the negative group converter 8, between the output terminals of the negative group converter 8 and between the terminals of the load 12, the voltage eo having a waveform indicated by a thick line in FIG.
p, eon and eo are obtained. Where eo is eop
And the average value of eon. The thin line shows the output voltage waveform of the three-phase AC power supply I, and the dotted line shows the fundamental wave components of the voltages eop, eon, and eo. In this way, the cycloconverter is used as a frequency conversion circuit that directly converts the power supply frequency to an arbitrary frequency within a lower range by controlling the gate signal of the thyristor. FIG. 6 shows a winding arrangement of a conventional three-phase transformer 2 used in a cycloconverter for one iron core leg. As shown in FIG. 6, the positive group winding 4 is wound around the iron core leg 13, the power supply winding 3 is wound around the outer circumference thereof, and the negative group winding 5 is further wound around the outer circumference thereof. .

In the above structure, of the frequency-converted single-phase AC voltage output from the output terminal of the cycloconverter, the positive half-wave is output through the positive group converter 6 and the negative half-wave is output through the negative group converter 8. Is output. Therefore, in order to make the AC output waveform symmetrical in positive and negative directions, it is necessary to make the positive group winding impedance and the negative group winding impedance equal. Therefore, conventionally, in order to make the leakage flux of the positive group winding 4 close to the iron core leg 13 the same as the leakage flux of the negative group winding 5 far from the iron core leg 13, the outer peripheral surface of the positive group winding 4 and the power winding The distance (hereinafter, referred to as an inner main gap) L1 between the inner peripheral surface of the wire 3 and the inner peripheral surface of the negative group winding 5 and the outer peripheral surface of the power supply winding 3 (hereinafter referred to as an outer main gap). L2)
The leakage magnetic flux was adjusted by making it larger than that in (1), and the positive group winding impedance and the negative group winding impedance were made equal.

[0005]

However, in the above-mentioned conventional configuration, since the winding diameters of the positive group winding 4 and the negative group winding 5 are different, a difference in resistance loss occurs due to a difference in circumferential length. In other words, although the positive group winding impedance and the negative group winding impedance are made almost equal by adjusting the inner main gap and the outer main gap, the ratio of the resistance component and the reactance component is significantly different, and this is the output of the cycloconverter. This is a factor that reduces the accuracy of the positive / negative symmetry of the waveform.

Further, as described above, in order to equalize the positive group winding impedance and the negative group winding impedance, the inner main gap needs to be made larger than the minimum dimension required for insulation. However, there is a problem in that the size of the device becomes large and the size of the entire device becomes large. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a positive group winding impedance and a negative group winding impedance including the resistance component and the reactance component, and to provide a compact and low loss transformer for a cycloconverter.

[0007]

According to a first aspect of the present invention, there is provided a cycloconverter transformer in which a conductor of a positive group winding and a conductor of a negative group winding are wound around an iron core leg in the axial direction so as to be adjacent to each other. It is characterized by being. In the cycloconverter transformer according to the second aspect of the present invention, the positive group winding and the negative group winding are arranged in a form adjacent to the iron core leg in the axial direction thereof, and the power supply winding is the positive group winding and the negative group winding. It is characterized in that it is divided into first and second winding portions so as to be arranged concentrically with respect to the wire.

[0008]

In the cycloconverter transformer according to the first aspect of the invention, the conductor of the positive group winding and the conductor of the negative group winding are wound around the iron core leg in a state of being adjacent to each other in the axial direction of the iron core leg. Because of the configuration, the positive group winding and the negative group winding have the same radial distance with respect to the iron core leg, and the relative positional relationship with respect to the power source winding, that is, the condition of the magnetic path is also the same. , The leakage reactances between the positive and negative group windings and the power supply winding are the same, the lengths of the positive and negative group windings are the same, and the winding resistances are the same.

According to the cycloconverter transformer of the second aspect of the present invention, the positive group winding and the negative group winding are arranged so as to be adjacent to the iron core leg in the axial direction thereof, and the power supply winding is the positive group winding. Since the first and second winding portions are divided so as to be arranged concentrically with respect to the line and negative group windings, the positive and negative group windings have the same length. As a result, the winding resistance becomes the same, the relative positional relationship becomes the same with respect to the first and second winding portions that are the divided power supply windings, and the leakage reactance becomes the same.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment (first invention) of the present invention will be described with reference to FIGS. The iron core leg 14 shown in FIG. 2 represents one of the three-leg iron cores for a three-phase transformer, and the positive and negative windings 15 and 1 are provided on the outer periphery of the iron core leg 14.
6 is arranged, and the power supply winding 17 is arranged on the outer periphery thereof.
As shown in FIG. 1, the positive and negative group windings 15 and 16 are wound around the iron core leg 14 by forming a positive group winding conductor L15 shown in white and a negative group winding conductor L16 shown in diagonal lines. The conductors L15 and L16 are, for example, superposed so as to be adjacent to each other in the axial direction of the core leg 14, and the conductors L15 and L16 are wound around the core leg 14 at the same time. The example of FIG. 1 shows an example in which the conductor is wound in two layers in the radial direction.
The dislocation is performed so that the vertical relation of 16 is reversed when the first layer is transferred to the second layer. In FIG. 1, L15i and L16i
Is the winding start end of the positive group winding 15 and the negative group winding 16,
L15o and L16o indicate the winding end ends of the positive group winding 15 and the negative group winding 16, respectively. On the other hand, the power supply winding 17 is concentrically wound around the outer periphery of the winding body composed of the positive and negative group windings 15 and 16 which are simultaneously wound in parallel on the iron core leg 14 as described above.

As described above, the conductor L15 of the positive group winding 15
And the conductor L16 of the negative group winding 16 are wound around the iron core leg 14 so as to be adjacent to each other in the axial direction of the iron core leg 14, the positive group winding 15 and the negative group winding 16 are The radial distances to the iron core legs 14 are the same, and the relative positional relationship to the power supply winding 17, that is, the condition of the magnetic path is also the same. As a result, positive and negative group windings 15 and 16
The leakage reactance between the power supply winding 17 and the power supply winding 17 is the same, the lengths of the positive and negative group windings 15 and 16 are the same, and the winding resistances thereof are the same.

A second embodiment (second invention) of the present invention will be described with reference to FIG. 3. A mode in which the positive group winding 15 and the negative group winding 16 are adjacent to the core leg 14 in the axial direction thereof. The positive group winding 15 is wound in the upper half region of the iron core leg 14, and the negative group winding 16 is wound in the lower half thereof. The power supply winding 17 is divided into first and second winding portions 17a and 17b, and their outer circumferences are arranged so as to be concentric with the positive group winding 15 and the negative group winding 16, respectively. Wrapped around.

Also in this configuration, the positive and negative group windings 1
5 and 16 have the same length and the same winding resistance, and the relative positional relationship to the first and second winding parts 17a and 17b which are the divided power supply windings 17. Also become identical to each other, and the leak reactances become identical to each other.

[0014]

In the cycloconverter transformer according to the first aspect of the present invention shown in FIG. 1, the positive group windings and the negative group windings have the same radial distance to the iron core leg, and the relative distance to the power source winding. The positional relationship is also the same, and as a result,
The leak reactance between each of the positive and negative group windings and the power supply winding becomes the same, and the length of each positive and negative group winding becomes the same, and the winding resistance becomes the same.

This means that not only the impedances of the positive group windings and the negative group windings are the same as each other, but also the ratios of the leak reactance component and the resistance component are the same, so that the output from the cycloconverter is performed. The accuracy of the positive / negative symmetry of the waveform is improved. Further, since the conductor of the positive group winding and the conductor of the negative group winding are wound around the iron core leg in a state of being adjacent to each other in the axial direction of the iron core leg, the main insulating gap is positive or negative. It suffices to have one place between the outer circumference of the winding and the inner circumference of the power supply winding, and it is not necessary to enlarge the insulating main gap for adjusting the leak reactance.

By reducing the insulating main gap, the winding is downsized, so that the amount of iron and the amount of copper are reduced, and it is possible to obtain a small-sized, lightweight and low-loss transformer.
In particular, since both positive and negative group winding conductors can be wound at the same time, the efficiency of winding forming work is improved. Also in the cycloconverter transformer according to the second aspect of the present invention, the positive and negative group windings have the same length, and the first and second winding portions that are divided power supply windings are provided. The relative positional relationship is also the same as each other, as a result, the winding resistance and the leakage reactance are the same, the accuracy of the positive and negative symmetry of the output waveform is improved, and a compact, lightweight and low loss transformer can be obtained. it can.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a winding configuration of positive and negative group winding conductors around one iron core leg of a transformer according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing an arrangement configuration of positive and negative group windings and power supply windings with respect to one iron core leg of the transformer according to the first embodiment of the present invention.

FIG. 3 is a view corresponding to FIG. 2 showing a second embodiment.

FIG. 4 is a circuit diagram showing a general single-phase cycloconverter.

5 is a voltage waveform diagram of each part of the cycloconverter shown in FIG.

FIG. 6 is a diagram showing an arrangement configuration of windings in a conventional cycloconverter transformer.

[Explanation of symbols]

14 is an iron core leg, 15 is a positive group winding, 16 is a negative group winding, 17
Is a power supply winding, 17a is a first winding portion, 17b is a second winding portion, L15 is a positive group winding conductor, and L16 is a negative group winding conductor.

Claims (2)

[Claims] 1. A power supply winding connected to an AC power supply and a positive group winding and a negative group winding respectively connected to a positive group winding converter and a negative group winding converter of a cycloconverter are wound around an iron core leg. In the transformer, the cycloconverter is characterized in that the conductor of the positive group winding and the conductor of the negative group winding are wound around the core leg in a state of being adjacent to each other in the axial direction of the core leg. Transformer. 2. A power supply winding connected to an AC power supply and a positive group winding and a negative group winding respectively connected to a positive group winding converter and a negative group winding converter of a cycloconverter are wound around an iron core leg. In the transformer consisting of, the positive group winding and the negative group winding are arranged in a form adjacent to each other in the axial direction of the iron core leg,
And a power supply winding, which is divided into first and second winding portions so as to be arranged concentrically with respect to the positive group winding and the negative group winding, respectively.