JPS5929133B2 - Rectifier transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a DC winding of a double star-connected rectifier transformer with an interphase reactor.

In a double star-connected rectifier circuit with an interphase reactor, the two three-phase groups operate like independent three-phase rectifiers, and each anode (2
It operates for a period of π/3+u), and overlap commutation of the anode current due to the leakage reactance of each group of transformers is performed. Here, u indicates the overlapping angle. Therefore, if the leakage reactance of each group is different, the anode current becomes unbalanced, causing problems such as direct current bias magnetization of the interphase reactor. Therefore, the DC winding of this type of transformer must be constructed to minimize the difference in leakage reactance between each group. FIG. 1 and FIG. 2a show cross sections of concentrically arranged windings of a conventionally used double star-connected rectifier transformer.

Reference numeral 1 indicates an iron J-ray; 2 indicates an AC winding; 3a and 3b indicate a first group of DC windings; and 4a and 4b indicate a second group of DC windings.

The DC winding shown in FIG. 1 has a structure in which the windings 3a and 4a of each group are finely divided into disk shapes, arranged alternately, and connected in parallel.

The DC winding shown in FIG. 2a has a structure in which two groups of windings 3b and 4b are wound together into a cylindrical shape.

FIG. 2b is a front view showing the DC winding of FIG. 2a. There are two things mentioned above.

In other words, the winding structure shown in Figure 1 is often used for large current, low voltage windings, but it requires a lot of effort to connect externally to the windings, and generally, due to the external connection of DC windings, AC windings 2. Because the DC winding is placed inside, it is difficult to install a voltage adjustment tap on the AC side, and the DC winding has a winding capacity that is V1 times that of the AC winding 2. The disadvantage is that the material is bulky. The structure shown in Fig. 2 is a structure used for windings of medium and small currents, but since the two groups of windings 3b and 4b of the DC winding are adjacent to each other, the two groups of windings 3b and 4b are adjacent to each other.
The insulation between 4b must be performed using a solid insulator, which has the drawback of requiring a lot of effort and insulation material.

On the other hand, as a winding structure in which the secondary windings of a transformer are divided into two groups, there is one in which a first group and a second group of windings 3c and 4c are arranged concentrically as shown in FIG. This structure simplifies the processing of the windings, but for the reasons explained below, there is a large difference in leakage reactance between the windings 3c and 4c of the first group and the second group. It cannot be applied to windings. In other words, the leakage reactance of a concentrically arranged transformer is expressed by the following equation.

x■ku■X1+X2・・・・・・(1)496・f
k
gk) (2) In the Ik equation, k: Ampere turns per layer h: Height of the winding Rk: Average radius of the air gap Rk': Average radius of the winding Gk: Width of the air gap Dk: Width of the winding.

Figure 3a shows a winding structure in which the ampere turns (n-1)k of each layer of the two groups of windings 3c and 4c of the DC winding are equally wound, and Figure 3b shows the winding structure of the AC winding 2 and 4c. FIG. 3c shows the magnetomotive force distribution between the AC winding 2 and the winding 4c of the second group of DC windings. (1),
From equations (2) and (3), the leakage reactance is proportional to the leakage magnetic flux, and the magnetic flux distribution inside the windings and the air gap between the windings is similar to the magnetomotive force distribution. This is because the leakage reactances of the windings are not equal. The present invention aims to provide a rectifier transformer that improves the drawbacks of conventional DC windings by manipulating the magnetomotive force distribution of the DC windings, and will be explained below with reference to the drawings. FIG. 4 shows an embodiment of the present invention. FIG. 4a shows two groups of DC windings 13 and 14 arranged concentrically, and the number of turns of each layer is changed to give an ampere turn (n- 1) Winding structures in which k is different and the width Gk of the gap between the two groups of windings 13 and 14 is different.

FIG. 4b shows a magnetomotive force distribution diagram between the AC winding 2 and the first group of DC windings 13, and FIG. 4c shows a magnetomotive force distribution diagram between the AC winding 2 and the second DC winding group 14. In the above formulas (1), (2), and (3), since the average radii Rk' and Rk of each layer winding and air gap are different in the concentrically arranged windings 13 and 14, the magnetomotive force distribution is adjusted according to the values. . That is, by adjusting the values of (n-1)K and gk, the leakage reactances of the two groups of windings 13 and 14 can be made equal. In this way, the present invention, which is configured to equalize the leakage reactance of the two groups by changing the number of turns in each layer of the DC winding and the width of the gap between the windings, simplifies the insulation process of the DC winding and improves the winding. It is possible to obtain a winding wire that has fewer connection points and is easy to work with.

Although the above explanation was based on the case where the DC winding is on the inside, it goes without saying that it can also be applied to a case where the DC winding is on the outside.

[Brief explanation of the drawing]

Figures 1 and 2a are cross-sectional views showing conventional windings, Figure 2b
is a front view showing the DC winding of No. 2a, FIG. 3a is a cross-sectional view of the winding without consideration of magnetomotive force distribution, FIG. 3b is a magnetomotive force distribution diagram of the first group, and FIG. 3c is a diagram of the second group. Group magnetomotive force distribution diagram, Figure 4a
4B is a sectional view of a winding according to an embodiment of the present invention, FIG. 4B is a magnetomotive force distribution diagram of the first group, and FIG. 4C is a magnetomotive force distribution diagram of the second group. 1...Iron core, 2...AC winding, 13.
...Winding of the first group of DC windings, 14... Winding of the second group of DC windings.

Claims (1)

[Claims] 1. When the two groups of DC windings in a double star connection with an interphase reactor are each divided into multiple layers and these are arranged concentrically, the number of turns in each layer of the two groups of windings may be made different. A rectifier transformer characterized in that the leakage reactances of the two groups of windings are equalized by making the widths between the layers different.