JPH0127430Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] The present invention relates to a transformer rectifier used in a double star rectifier circuit, and in particular uses a sealed conductor in the secondary winding of a rectifier transformer to improve impedance characteristics. Regarding improvements to .

[Technical background of the invention and its problems]

Rectifiers used in chemical equipment and aluminum electrolysis require particularly low voltage and high current, so double star rectifier circuits are often adopted. This circuit rectifies two sets of three-phase half-waves using the action of an interphase reactor, and the secondary winding of the transformer in this case is composed of two windings corresponding to both three-phase systems. Become.

In such a double star rectifier circuit, if there is a difference in impedance between the two three-phase systems, a current imbalance will occur, which will not only lead to a lack of capacity in the windings with low impedance, but also cause problems in the interphase reactor and rectifier transformer. This may cause DC bias in the iron core of the main body of the device.
Causes problems with characteristics. Therefore, the impedances of both three-phase systems must be made as equal as possible.

Figure 1 shows an example of the secondary winding 1 of a rectifier transformer used in a double star rectifier circuit. 4, 4 and are wound together.
2a, 2b and 3a, 3b are leads for each winding, and a total of four are required, corresponding to the winding start and winding end of the two windings. These openings 2a, 2
b, 3a, and 3b are as shown in part A in Figure 1.
It is firmly connected to the sealed conductors 2 and 3 by MIG welding or the like.

FIG. 2 is a sectional view showing a state in which such a winding is concentrically wound around the iron core 6 together with the primary winding 5, and 7 is the main insulation that separates the primary winding 5 and the secondary winding 1. This is the gap between In the secondary winding 1 using sealed conductors 2 and 3, as shown in FIG. It is composed of a conductor 3 and a winding 1B relatively far from the main insulation 7.
At this time, when comparing the respective windings 1A and 1B, the gaps between the main insulations 7 are d ₁ and d ₂ as shown in FIG. 3, which means that they are different. This causes a difference in the number of interlinking magnetic fluxes, resulting in the above-mentioned impedance mismatch.

As a conventional measure to avoid this, the fourth
As shown in the figure, each winding has leads 2a, 2b and 3.
By shifting a and 3b by half a turn, with respect to the primary winding 5,
There was a way to obtain a completely symmetrical arrangement.

Generally, a large current rectifier is configured as a so-called transformer rectifier that combines a transformer section and a rectifier section into an integral structure. In this case, if the conventional impedance matching by half-turn shift is adopted, a configuration as shown in FIG. 5 will be obtained. In other words, in a low-voltage, high-current type rectifier circuit, the impedance drop in the leads connecting each outlet 9 of the secondary winding of the transformer section and the rectifier section becomes large, and the impedance drop per 1 m becomes: When converted to percent impedance, it reaches several percent. Therefore, as shown in FIG. 5, by dividing the rectifier section 8 into two and disposing them on both sides of the tank that constitutes the transformer section 9, the wiring of the leads 10 can be made completely symmetrical to achieve impedance matching. There used to be. However, such a configuration has the following drawbacks.

(1) Since the rectifier section 10 is divided into two, two sets of rectifying element stacks are required, and two sets of casings to house them are also required, which is extremely uneconomical.

(2) Both sides of the tank of the transformer section 9 are connected to the rectifier section 1.
Since the transformer is covered with zero, there is insufficient space to install a radiator etc. for cooling the transformer section, making it impossible to adopt a self-cooling type and having to change to a water-cooled type or the like. This is inconvenient from a maintenance standpoint.

[Purpose of invention]

The present invention was created in consideration of the above circumstances, and aims to provide a transformer rectifier that can be economically configured by matching the impedance of each three-phase circuit on the secondary side and by rationally arranging the rectifier section. purpose.

[Summary of the idea]

In this invention, the primary winding and the secondary winding are arranged concentrically through the main insulation and wound around the iron core, and the secondary winding is integrated between a pair of sealed conductors through the insulator. A transformer part that is wound to form two windings, and the leads of these two windings are pulled out from the same point in the circumferential direction, and the leads of each winding of the secondary winding of this transformer part. and a rectifier section having a rectifying element stack connected via a lead, the lead of the winding on the side closer to the main insulation of the secondary winding,
The lead on the side farther from the main insulation is longer than the lead, and the impedance of both winding circuits is matched by the impedance drop caused by the longer lead.

[Example of idea]

An embodiment of the present invention will be described below with reference to FIGS. 6 and 7. FIG. 6 is a cross-sectional view showing a plane of the transformer section, and FIG. 7 is a cross-sectional view showing a state in which the transformer section configured as shown in FIG. 6 and the rectifier section are connected.

The secondary winding 1 is wound by alternately stacking sealed conductors 2, 3 and an insulator (not shown), and openings 2a, 2b, 3 at the beginning and end of each sealed conductor 2, 3.
a and 3b are drawn out from the same location in the circumferential direction. The secondary winding 1 and the primary winding 5 are wound around an iron core 6, and stored in a tank to form a transformer section 9.
is configured. On one side of the tank of the transformer section 9, a rectifier section 8 having a rectifier stack housed in a housing is provided. The rectifying element stack of the rectifier section 8 and the appropriate outlet of the secondary winding 1 of the transformer section 9 are connected by leads 10a and 10b, and here the sealed conductor 2 of the secondary winding 1 is connected. The inner winding made up of the sealed conductor 3 is close to the main insulation and has low impedance, so it is connected to the rectifier part 8 using a long lead 10a, whereas the outer winding made of the sealed conductor 3 has a high impedance and is therefore short. It is connected to the rectifier section 8 using the lead 10b. That is, the lead 10a is longer than the lead 10b by L, and the impedance drop due to the length L cancels out the impedance difference due to the difference in the number of interlinked magnetic fluxes of each winding on the secondary side. It is something. Therefore, in FIG. 7, the impedances of each three-phase circuit are perfectly matched, and even if the rectifier section 8 is not divided for the purpose of impedance matching as shown in FIG. It can be placed in a concentrated manner. Therefore, not only can the casing of the rectifier section 8 be configured with one casing, but also a space for attaching a radiator to the tank of the transformer section 9 is created, so that a self-cooling type can be adopted.

[Effect of idea]

As described above, according to the present invention, it is possible to obtain a transformer rectifier that can easily match the impedances of both three-phase circuits and can be constructed economically.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the secondary winding of a rectifier transformer using a sealed conductor, Fig. 2 is a sectional view showing the relative relationship between the core, the primary winding, and the secondary winding, and Fig. 3
The figure is an explanatory diagram showing that impedance mismatch occurs due to the arrangement of sealed conductors, Fig. 4 is an explanatory diagram showing a conventional winding structure for dealing with impedance mismatch, and Fig. 5 is a conventional transformer. FIG. 6 is a sectional plan view of a transformer section used in the transformer rectifier according to the present invention, and FIG. 7 is a cross-sectional view showing an embodiment of the transformer rectifier according to the present invention. 1...Secondary winding, 2, 3...Sealed conductor, 4
... Insulator, 2a, 2b, 3a, 3b ... Lead, 5 ... Primary winding, 6 ... Iron core, 7 ... Main insulation, 8 ... Rectifier section, 9 ... Transformer section, 10, 1
0a, 10b...Read.

Claims (1)

[Scope of utility model registration request] The primary winding and the secondary winding are arranged concentrically through the main insulation and wound around the iron core, and the secondary winding is integrally wound between a pair of sheet-shaped conductors through an insulator. A transformer section consisting of two windings, with the leads of these two windings drawn out from the same point in the circumferential direction, and the leads and leads of each winding of the secondary winding of this transformer part. a rectifier section having a rectifying element stack connected to the secondary winding;
A transformer rectifier characterized in that the lead of the winding closer to the main insulation is longer than the lead of the winding farther from the main insulation.