JP2723322B2 - Transformer for cyclo converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention] (Industrial application field) The present invention relates to a primary winding connected to an AC power supply, and a primary winding connected to a positive group converter and a negative group converter of a cyclo converter, respectively. The present invention relates to a transformer for a cycloconverter, comprising a plurality of secondary windings.

(Prior Art) FIGS. 4 and 5 show an example of this type of cycloconverter transformer. FIG. 4 is a diagram showing a schematic electrical configuration for a single phase of the cycloconverter. In FIG. 4, a transformer 1 for a cycloconverter has a primary winding 2 and two secondary windings 3,4. The primary winding 2 is connected to an AC power supply, for example, a commercial three-phase AC power supply 5. One secondary winding 3 is connected to the positive group converter 7 of the cycloconverter 6, and the other secondary winding 4 is connected to the negative group converter 8 of the cycloconverter 6. Positive group converter 7 and negative group converter 8
Are connected in anti-parallel via the circulating current suppressing reactors 9 and 10 as shown in FIG. Each converter 7,
8, for example, a thyristor is configured as a three-phase bridge control circuit. Then, each midpoint 9a of the reactors 9 and 10
And 10a are output terminals of the cycloconverter 6. The positive half-wave of the single-phase alternating current output from this output terminal is supplied by the positive group converter 7, and the negative half-wave is supplied by the negative group converter 8.

Here, the general winding arrangement of the transformer 1 will be described in detail with reference to FIG. As shown in FIG.
The one secondary winding 3 is wound around the iron core 11a of the eleventh winding, the primary winding 2 is wound around the outer periphery of the secondary winding 3, and the other secondary winding is wound around the outer periphery of the primary winding 2. Wire 4 is wound. The primary winding 2 includes a tap winding 12 and a primary main winding 13 for responding to voltage fluctuations of the commercial three-phase AC power supply 5. The tap winding 12 is provided outside the primary main winding 13 and is disposed between the primary main winding 13 and the secondary winding 4.

In the above configuration, the positive half-wave of the single-phase AC output from the output terminal of the cycloconverter 6 is supplied by the positive group converter 7 and the negative half-wave is supplied by the negative group converter 8. For this reason, in order to make the AC output waveform symmetrical between positive and negative, it is necessary to make the positive group impedance and the negative group impedance equal. In this case, both secondary windings 3, 4
Since they have the same capacitance and voltage, they can have the same winding configuration such as conductor size and layer configuration. On the other hand, the distance between the inner circumferential surface of the primary winding 2 and the outer circumferential surface of the secondary winding 3 (hereinafter referred to as the inner main gap) is determined by the outer circumferential surface of the primary winding 2 and the outer circumferential surface of the tap winding 12 in this case. When the distance between the magnetic flux and the inner peripheral surface of the secondary winding 4 (hereinafter referred to as the outer main gap) is made equal to make the distribution of the leakage magnetic flux affecting the positive group impedance and the negative group impedance equal, the secondary Since the winding diameter of the winding 4 is larger than the winding diameter of the secondary winding 3, the negative group impedance is larger than the positive group impedance. For this reason, by making the inner main gap larger than the outer main gap, increasing the leakage magnetic flux on the inner main gap side, and increasing the positive group impedance, the values of the positive group impedance and the negative group impedance are made equal. ing.

(Problems to be Solved by the Invention) Now, in the above-described conventional configuration, how each value of the positive group impedance and the negative group impedance changes depending on whether or not current is supplied to the tap winding 12 of the primary winding 2 is not supplied. Consider the effect.

In the above configuration, the positive half wave is supplied to the secondary winding 3,
The secondary winding 4 is energized with a negative half-wave, and the primary winding 2 is energized with a full wave. In this case, the distribution of the leakage magnetic flux affecting the positive group impedance and the negative group impedance is as shown in FIG. In FIG. 6, the leakage magnetic flux distribution when the entire tap winding 12 is energized, that is, the leakage flux distribution at the time of the highest tap is indicated by a solid line. . In addition, the inner main gap and the outer main gap are set to be equal in order to easily compare the leakage magnetic flux distributions for the positive group and the negative group impedance. As is clear from FIG. 6, the leakage flux for the positive group impedance decreases as the taps are sequentially switched from the highest tap to the lowest tap, so that the positive group impedance decreases. On the other hand, the leakage flux for the negative group impedance increases as the taps are sequentially switched, so that the negative group impedance increases. Accordingly, there is a problem that the positive group impedance and the negative group impedance greatly differ according to the tap switching, and the distortion of the output waveform of the cycloconverter 6 increases.

Accordingly, an object of the present invention is to provide a voltage for a cycloconverter capable of minimizing a difference between a positive group impedance and a negative group impedance associated with tap switching and preventing distortion of a cycloconverter output waveform as much as possible. To provide a vessel.

[Effect of the Invention] (Means for Solving the Problems) A transformer for a cycloconverter according to the present invention includes a primary winding composed of a primary main winding and a tap winding and connected to an AC power supply. In a device provided with two secondary windings provided inside and outside the wire and connected respectively to a positive group converter and a negative group converter of a cycloconverter, the tap winding of the primary winding is referred to as the primary main winding. It has a feature in that it is disposed between the secondary winding and the secondary winding located on the inner side.

(Action) In order to make the positive group impedance and the negative group impedance equal, the inner main gap is originally made larger than the outer main gap. In such an arrangement,
In the conventional configuration, the tap winding of the primary winding is disposed between the primary main winding and the secondary winding located outside the primary winding, that is, on the outer main gap side. On the other hand, according to the above means, the tap winding of the primary winding is disposed between the primary main winding and the secondary winding located inside the primary winding, that is, on the inner main gap side. Therefore, since the tap winding with the same number of turns is originally arranged on the wide side of the gap, the rate of change of the leakage magnetic flux due to the tap switching is smaller than that of the conventional case where the tap winding is originally arranged on the narrow side of the gap. Become smaller. Therefore, the fluctuation of the impedance is reduced. As a result, the difference between the positive group impedance and the negative group impedance associated with the tap switching can be reduced as compared with the related art.

(Embodiment) Hereinafter, a first embodiment of the present invention will be described with reference to FIG. 1 and FIG.

First, in FIG. 1, one secondary winding 22 is wound around an iron core leg 21a of an iron core 21, a primary winding 23 is wound around the outer periphery of the secondary winding 22, and the primary winding 23 is further wound. The other secondary winding 24 is wound around the outer periphery of. Thus, two secondary windings 22 and 24 are provided inside and outside the primary winding 23. In this case, the inner secondary winding 22 is connected to a positive group converter of a cyclo converter (not shown), and the outer secondary winding 24 is connected to a negative group converter of a cyclo converter.
The primary winding 23 includes a primary main winding 25 and a tap winding 26, and is connected to a commercial three-phase AC power supply (not shown). By changing the number of turns of the primary winding 23 by switching the taps of the tap winding 26, it is possible to cope with the voltage fluctuation of the commercial three-phase AC power supply.

Here, the tap winding 26 is provided inside the primary main winding 25 and is disposed between the primary main winding 25 and the secondary winding 22 located inside the primary main winding 25. The inner main gap d1, which is the distance between the inner peripheral surface of the primary winding 23, in this case, the inner peripheral surface of the tap winding 26, and the outer peripheral surface of the secondary winding 22, is referred to as the outer peripheral surface of the primary winding 23. In this case, the outer main gap d2, which is the distance between the outer peripheral surface of the primary main winding 25 and the inner peripheral surface of the secondary winding 24, is set to be larger. Thereby, the values of the positive group impedance and the negative group impedance are made equal.

According to the present embodiment having such a configuration, the tap winding 26 of the primary winding 23 is provided between the primary main winding 25 and the secondary winding 22 located inside the primary winding 25, that is, the inner main winding having an originally large gap. Since the tap winding 12 is disposed on the gap d1 side, the number of turns of the tap winding is the same, that is, in the radial direction, as compared with the conventional configuration (see FIG. 5) in which the tap winding 12 is disposed on the outer main gap side having a small gap. Considering that the thickness dimensions are the same, the rate of change of the leakage magnetic flux accompanying the tap switching becomes small. For this reason, the fluctuation of the impedance is reduced. Therefore,
The difference between the positive group impedance and the negative group impedance associated with the tap switching can be reduced as compared with the related art. As a result, it is possible to prevent distortion of the output waveform of the cycloconverter from increasing as much as possible. In this embodiment, the distribution of the leakage magnetic flux affecting the positive group impedance and the negative group impedance is as shown in FIG. In FIG. 2, the leakage flux distribution when the entire tap winding 26 is energized, that is, the leakage flux distribution at the time of the highest tap is indicated by a solid line. .

By the way, in the conventional configuration (see FIG. 5), since the tap winding 12 is originally disposed on the outer main gap side having a small gap, the outer peripheral surface of the tap winding 12 and the inner peripheral surface of the outer secondary winding are provided. Between the tap and the tap lead, the tap lead cannot be passed through.
Had to be provided on both upper and lower ends. For this reason, the work of connecting the lead wire to the tap portion of the tap must be performed at both the upper and lower ends of the tap winding 12, and there is a disadvantage that workability is poor. On the other hand, in the above embodiment, the tap winding 26 is arranged between the primary main winding 25 and the secondary winding 22 located inside the primary main winding 25.
The gap between the inner peripheral surface and the outer peripheral surface of the inner secondary winding is set large, so that the lead wire of the tap can pass through the gap. Accordingly, the tap portion of the tap can be provided only on the upper end side of the tap winding, for example, and the workability of connecting a lead wire to the tap portion of the tap can be improved.

In the above embodiment, the inner main gap is the same as the conventional one (see FIG. 5). In this case, when the tap winding 26 is not energized, the thickness of the tap winding 26 in the radial direction is reduced. Only the inner main gap is wider than before,
The leakage magnetic flux increases and the impedance increases. Therefore, paying attention to this, instead of the above embodiment,
When the tap winding is not energized, that is, the gap between the inner peripheral surface of the primary main winding and the outer peripheral surface of the inner secondary winding is set to the conventional value (the fifth type).
(See the figure). In this case, the inner main gap (gap between the inner peripheral surface of the tap winding and the outer peripheral surface of the inner secondary winding) can be made smaller than before, so that the primary winding and the secondary winding outside the primary winding can be reduced. The diameter of each winding of the winding can be reduced, the overall configuration can be reduced in size and weight, the amount of conductors used can be reduced, and the loss can be reduced.

FIG. 3 shows a second embodiment of the present invention, and points different from the first embodiment will be described. As shown in FIG. 3, the secondary winding 27 in place of the secondary winding 22 is composed of two partial secondary windings 27a and 27b arranged vertically. The primary winding 28 replacing the primary winding 23 includes a primary main winding 29 and a tap winding 30. The primary main winding 29 is composed of two partial primary main windings 29a and 29b arranged vertically.
Further, the tap winding 30 is composed of two partial tap windings 30a and 30b which are also arranged vertically. Further, the secondary winding 31 replacing the secondary winding 24 is composed of two partial secondary windings 31a and 31b arranged vertically. This is equivalent to the configuration in which two transformers for the cycloconverter shown in the first embodiment are provided on the upper and lower sides.

Therefore, the same operation and effect as in the first embodiment can be obtained in the second embodiment, but in particular, when the two cycloconverter transformers shown in the first embodiment are used, the above-described operation is performed. A single transformer according to the second embodiment can handle this.

[Effects of the Invention] As is apparent from the above description, the present invention has a configuration in which the tap winding of the primary winding is arranged between the primary main winding and the secondary winding located inside the primary winding. In addition, the difference between the positive group impedance and the negative group impedance due to the tap switching can be reduced as much as possible, and there is an excellent effect that distortion of the output waveform of the cycloconverter can be prevented as much as possible.

[Brief description of the drawings]

1 and 2 show a first embodiment of the present invention. FIG. 1 is a partial longitudinal sectional view, and FIG. 2 is a view showing the distribution of leakage magnetic flux. FIG. 3 is a diagram corresponding to FIG. 1 showing a second embodiment of the present invention. 4 to 6 show a conventional configuration, FIG. 4 is an electrical configuration diagram, and FIG.
FIG. 6 and FIG. 6 are equivalent to FIG. 1 and FIG. 2, respectively. In the drawings, 22 and 27 indicate secondary windings, 23 and 28 indicate primary windings, 24 and 31 indicate secondary windings, 25 and 29 indicate primary main windings, and 26 and 30 indicate tap windings.

Claims (1)

(57) [Claims] 1. A primary winding composed of a primary main winding and a tap winding and connected to an AC power supply, and connected to a positive group converter and a negative group converter of a cycloconverter provided inside and outside of the primary winding. In a device provided with two secondary windings, a tap winding of the primary winding is arranged between the primary main winding and a secondary winding located inside the primary main winding. Transformer for cyclo converter.