JPS5929132B2 - 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 takes place. Here, u indicates the overlapping angle. Therefore, if the leakage reactance of each group is different, the anode currents become 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. FIGS. 1 and 2a show cross sections of concentrically arranged windings of a conventionally used double star-connected rectifier transformer.

1 is the iron wire, 2 is the AC winding, and 3a and 3b are the first DC windings.
Group windings 4a, 4b are windings of the 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. The structure described above has advantages and disadvantages depending on the capacity of the DC winding and the insulation level cooling method, and has the following characteristics. The structure shown in Figure 1 is often used for high current, low voltage windings, but it requires a lot of effort to connect externally to the windings, and generally the AC winding 2 is connected inside because of the external connection of the DC winding. Therefore, it is difficult to install a voltage adjustment tap on the AC side, and the DC winding is J
Since the winding capacity is i times larger, there is a disadvantage that the winding material is larger than when the DC winding is arranged inside. The second structure is a structure used for windings of medium and small currents, but since the two groups of windings 3b and 4b are adjacent to each other, the second group of windings 3b and 4b are adjacent to each other.
The insulation treatment between the sections 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, the two groups of windings 3c and 4c are divided into multiple layers and these are arranged concentrically, as shown in Fig. 3. be. This structure simplifies the processing of the windings, but due to the reasons explained below, there is a large difference in leakage reactance between the first and second group windings. cannot be carried out. In other words, the leakage reactance of the concentrically arranged transformer windings is expressed by the following equation.

X-HXI+X2... (1)X1■■■■
6, 're', Imonkama ((n-i)ι・rk-gk)...
...... (2) In the construction type A, X゜Leakage reactance Xl゜Leakage reactance generated in the gap X2: Leakage reactance generated inside the coil Eg. Induced voltage I due to leakage magnetic flux Winding current F. Frequency (n-1)k: Ampere turns per layer h: Height of the winding Rk: Average radius of the gap Rk': Average radius of the winding Gk: Width of the gap Dk: Width of the winding.

Figure 3a shows a winding structure in which two groups of windings 3c and 4c of the DC winding are wound with equal ampere turns (n 1) k in each layer, and Figure 3b shows the winding structure of the AC winding 2 and FIG. 3c shows a magnetomotive force distribution diagram between the AC winding 2 and the winding 4c of the second DC winding group. (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. Winding wire 3c
, 4c are not equal. An object of the present invention is 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, in which FIG. Make the number of times different.

That is, the ampere turns (n-1)k are made different. Figure 4b is a magnetomotive force distribution diagram between the AC winding 2 and the winding 13 of the first group of DC windings, and Figure 4c is a diagram of the magnetomotive force distribution between the AC winding 2 and the winding 14 of the second group of DC windings. A magnetic force distribution diagram is shown. In Equations 1, 2, and 3, since the average radius Rk' of the windings in each layer and the average radius Rk of the air gaps are different in the concentrically arranged windings, the magnetomotive force distribution is adjusted according to these values.

In other words, by adjusting the value of (n-1)k, the second group of windings 13
, 14 can be made equal.
The present invention, which is configured to equalize the leakage reactance of two groups of windings by changing the number of turns in each layer of the DC winding, simplifies the insulation treatment of the DC winding and reduces the number of connections between the windings. It is possible to obtain a winding wire that is easy to work with.

It should be noted that although the description has been based on the case where the DC winding is located on the inside, it goes without saying that it can also be applied to a case where the DC winding is located on the outside.

[Brief explanation of drawings]

Figures 1 and 2a are cross-sectional views showing conventional windings, Figure 2b
is a front view showing the DC winding in Fig. 2a, Fig. 3a is a cross-sectional view of the winding without considering the magnetomotive force distribution, Fig. 3b is a magnetomotive force distribution diagram of the first group of windings, Figure c is the magnetomotive force distribution diagram of the second group.
FIG. 4a 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 of windings, and FIG. 4c is a magnetomotive force distribution diagram of the second group. 1... Iron collection 2... AC winding, 13.
...DC winding 1st group, 14...DC winding 2nd group.

Claims (1)

[Claims] 1. 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, by varying the number of turns in each layer of the two groups of windings. A rectifier transformer characterized in that two groups of windings have equal leakage reactance.