JPH11111538A - Transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transformer, the iron loss of which is reduced to a theoretical value of 0%. SOLUTION: A transformer is constituted to theoretically suppress the primary-side current to zero by inserting a capacitor which makes infinite the equivalent impedance viewed from the primary side at no-load and has a capacitance C. The capacitor can be formed by winding a metal foil between some phases of a secondary winding L2 wound in multiple layers and connecting the metal foil to one of the secondary terminals. The capacitance of the capacitor can be adjusted by adjusting the width or the length of the metal foil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer, and more particularly, to a transformer which eliminates iron loss at no load.

[0002]

2. Description of the Related Art In general, a transformer has a rated capacity of 1 to 3 due to iron loss even when there is no load, regardless of whether it is for power transmission and distribution or equipment.
% Power loss.

For example, when the main power is turned on and power is supplied to the primary side of the transformer, the auxiliary switch is turned on / off.
It is said that, for example, a television transformer, an air conditioner, a stereo, etc., which supplies electric power to the secondary side by operating a remote controller, power equivalent to about 6,600 yen per year per house is consumed by iron loss.

Therefore, conventionally, as a means for reducing the above-mentioned iron loss, research has been carried out by focusing only on the material of the iron core, but in reality, no satisfactory results have been obtained.

[0005]

That is, even when an iron core material which is said to have the least iron loss at present is used, 1 to 3% of iron loss occurs at no load.

The present invention has been proposed based on the above-mentioned conventional circumstances, and has as its object to provide a transformer in which iron loss is reduced to a theoretical value of 0%.

[0007]

The present invention employs the following means to achieve the above object. That is, as shown in FIG. 1, the transformer of the present invention inserts a capacitor having an electrostatic capacitance C, which makes the equivalent impedance as viewed from the primary side at no load to infinity, into the secondary side. The configuration is such that the current on the secondary side is suppressed to zero.

Further, the capacitor is formed by winding a metal foil between any phases of a secondary winding wound in layers and connecting one secondary terminal to the metal foil. You can also. Here, the capacitance of the capacitor can be adjusted by adjusting the width or length of the metal foil.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a transformer according to the present invention, as shown in FIG. 1, a capacitor having a capacitance C represented by the following equation is inserted on the secondary side. That is, the capacitance C is f,
When the equivalent reactance viewed from the primary side is L and the angular frequency is ω,

[0010]

(Equation 1)

That is,

[0012]

(Equation 2)

[0013] Therefore, the impedance of the secondary side when there is no load as viewed from the primary side or the secondary side becomes an infinite theoretical value, and the current on the primary side is theoretically suppressed to zero.

Hereinafter, the present invention will be described in detail with reference to embodiments. First, as shown in FIG. 1, in a television transformer (primary side V ₁ : 100 V, secondary side V ₂ : 30 V) to which the rated voltage is applied from the primary side, the static electricity of the capacitor inserted in the secondary side is set. Table 1 shows the test results of measuring the primary current I ₁ when the capacitance C was changed.

[0015]

[Table 1]

Test No. 1 is a test in the case where no capacitor is provided. In this case, the primary current I ₁ passed by 0.1 A. Test No. 2-7, each have Bei capacitor of capacitance C shown in Table 1, the primary current I ₁ is changed to the V-shape by the capacitance C of the capacitor as shown in FIG. Therefore, the primary current I ₁ may be selected capacitance C of the smallest capacitor.
From FIG. 2, it can be seen that when the capacitance is 50 μF, the primary current I ₁ is the smallest at 0.042 A. This value is the same as the test No. This is less than half of the primary current I ₁ 0.1 A when no capacitor is provided.

Next, as shown in FIG. 3, a transmission / distribution transformer (primary side V ₁ : 6600) to which a rated voltage is applied from the secondary side.
V, the secondary side V ₂ : 210 V), the current I ₂ flowing on the secondary side and the current I _C flowing on the capacitor when the capacitance C of the capacitor inserted on the secondary side is changed.
Table 2 shows the test results of the measurement of.

[0018]

[Table 2]

Test No. 8 is a test without a capacitor. In this case, the current I ₂ flowing on the secondary side flowed 0.4 A. Test No. 9 to 12 are shown in Table 2
And Bei the capacitor capacitance C shown in, the current I ₂ flowing through the secondary side by the electrostatic capacitance C of the capacitor as shown in FIG. 4 is changed to V-shape. Therefore, the current I ₂ flowing through the secondary side may be selected capacitance C of the smallest capacitor. From FIG. 4, when the capacitance is 10 μF, the current I ₂ flowing on the secondary side is 0.2 A
It turns out that it is the smallest. This value is the test N
O. 8 is half the current I ₂ 0.4 A flowing on the secondary side when no capacitor is provided. Also, when the capacitance is 1
At 0 μF, the current I _C flowing through the capacitor is 0.4 A. 8 is equal to the value of the current flowing to the secondary side when the capacitor is not provided, and satisfies Expression 2 above. Therefore, it is only necessary to select a capacitance that makes the current I _C flowing through the capacitor equal to the current I ₂ flowing to the secondary side when no capacitor is provided.

Here, in the secondary winding of the present invention, as shown in FIG. 5, a metal foil 2 is wound around an insulating paper 1 between any layers. Then, as shown in FIG. 6A, the metal foil 2 is connected to one of the secondary terminals at the connection point 5, and functions as a capacitor electrode. Therefore, it can be said that the circuit shown in FIG. 6A is equivalent to the circuit shown in FIG. Here, since it is formed as described above, it is possible to adjust the capacitance C by adjusting the width or length of the metal foil 2.

[0021]

According to the present invention, it is possible to provide a transformer in which iron loss is reduced to a theoretical value of 0%, and it is possible to obtain a transformer having a very small no-load loss in the embodiment.

Further, the capacitance of the capacitor can be adjusted by adjusting the width or length of the metal foil.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of one embodiment of the present invention.

FIG. 2 is a primary current characteristic diagram of the present invention.

FIG. 3 is a circuit diagram of another embodiment of the present invention.

FIG. 4 is a characteristic diagram of a current flowing to a secondary side according to the present invention.

FIG. 5 is a sectional view of a secondary winding according to the present invention.

FIG. 6 is a schematic diagram of a secondary side of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulation paper 2 Metal foil 3 Low voltage winding 4 High voltage winding 5 Connection point C Capacitance of capacitor

Claims (3)

[Claims] 1. A transformer, wherein a capacitor having a capacitance that makes the equivalent impedance viewed from the primary side or the secondary side when no load is applied to infinity is inserted in the secondary side. 2. The capacitor according to claim 1, wherein the capacitor is formed by winding a metal foil between any two phases of a secondary winding wound in layers and connecting one of the secondary terminals to the metal foil. The transformer according to claim 1. 3. The transformer according to claim 2, wherein the capacitance is adjusted by adjusting a width or a length of the metal foil.