JPH0442887Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a common mode chiyoke coil in which a pair of windings are applied so that the magnetic cores are wound in opposite directions to each other.
In particular, the present invention relates to a chiyoke coil used as a noise filter coil applied in a wide frequency range including a frequency range of 5KHz to 150KHz.

Conventionally, in this type of noise filter noise filter coil, a ferrite or powder magnetic core has been used as the magnetic core. Ferrite has a relatively high magnetic permeability and good frequency characteristics, so when used as a noise filter coil, high attenuation can be expected, but in a relatively low frequency range (e.g.
It has been difficult to obtain a noise filter with high attenuation in the frequency range (5KHz to 150KHz). The reason for this is thought to be that ferrite has low magnetic permeability in the low frequency range, making it impossible to obtain high inductance. On the other hand, powder magnetic cores have poor frequency characteristics, and when used as noise filter coils, they have the disadvantage that, like ferrite, they cannot ensure a large amount of attenuation in a relatively low frequency range.

The purpose of this invention is to create a chiyoke coil that can construct a noise filter with high attenuation in a wide frequency range, including the frequency range of 5 KHz to 150 KHz, by using an amorphous magnetic alloy with specific frequency characteristics as a magnetic core. It is about providing.

According to the present invention, in a chiyoke coil for a noise filter in which a pair of winding wires are wound oppositely to each other on a magnetic core, the initial magnetic permeability of the magnetic core is 10 KHz.
A chiyoke coil for a noise filter, characterized in that it uses an amorphous magnetic alloy that has a frequency characteristic of substantially 100,000 in the frequency range of 100,000 or more in the frequency range of 10KHz or less, and that is inversely proportional to the frequency in the frequency range of approximately 10KHz or more. is obtained.

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 shows an embodiment of a chiyoke coil for a noise filter according to the present invention, which is made of a cobalt-iron amorphous magnetic alloy (material name: ACF-2).
A thin ribbon 1 of
4 are wound in opposite directions.

Here, the amorphous magnetic alloy (ACF-2 material) that is the material of ribbon 1 has a saturation magnetic flux density of B ₁₀ (magnetizing force of 10 Oe
magnetic flux density) is 5.5KGauss, coercive force Hc is
It has excellent magnetic properties with an effective magnetic permeability μe of 55,000 at 0.01Oe and 1KHz.

Further, FIG. 2 shows the frequency characteristics of the initial magnetic permeability μ _i of the amorphous magnetic alloy (ACF-2 material) that is the material of the ribbon 1. At a frequency of 10KHz, the initial permeability μ _i
is 100,000 in nature, and in the frequency range where the frequency is approximately 10 KHz or less, the initial magnetic permeability μ _i is extremely large, approximately 100,000 or more, and in the frequency range where the frequency is approximately 10 KHz or more, the initial magnetic permeability μ _i is When it goes up by one digit, it goes down by one digit, that is, μ _i ×=K (K: constant, in this example
10) Shows characteristics that satisfy ⁹ .

Generally, the inductance L of the coil is proportional to the magnetic permeability μ of the magnetic core 2 (L = K′ μ (K′: constant)), and the inductive reactance X _L is X _L = 2πL, so μ×
= _{K, the inductive reactance X L is} constant as It should be.

In fact, FIG. 3 shows an example of measuring the frequency characteristics of the absolute value |Z| of the impedance Z of the coil shown in FIG. The value |Z| exhibits almost flat characteristics in a frequency range of 10 KHz or higher. In addition, impedance Z
It goes without saying that the size of the noise filter is set to a value that can ensure the required amount of attenuation as a noise filter.

As described above, the present invention has a characteristic that the impedance L of the coil is inversely proportional to the frequency in a frequency range of approximately 10 KHz or more. Furthermore, the attenuation characteristic of the noise filter using the Chiyork coil according to the present invention provides an almost constant amount of attenuation over the entire frequency range, so it has a stable amount of attenuation against external noise.

Figure 4 shows the frequency characteristics of the attenuation amount A when the Chiyork coil according to the present invention and the Chiyork coil using a conventional Mn/Zn ferrite core are used as the inductance L of a noise filter as shown in the equivalent circuit of Figure 5. A diagram is shown, showing an example where C _x in FIG. 5 is 0.47 μF and C _y is 3300 pF. In Fig. 4, the solid line shows the case where the inductance L (Fig. 5) is the case where the Chi-Yoke coil according to the present invention is used, and the broken line shows the case where the inductance L (Fig. 5) is the case where the Chi-Yoke coil with the conventional Mn/Zn ferrite core is used. There is.
As is clear from Figure 4, the noise filter using the chiyoke coil of this invention is different from the conventional 150K noise filter.
Compared to noise filters using chiyok coils with ferrite cores that were used above Hz, high attenuation can be obtained in the low frequency range (5KHz to 150KHz) and can be used from low to high frequency ranges.

In the embodiment shown in Fig. 1, an example is shown in which the winding of the magnetic core 2 is a single phase, but it goes without saying that it can be easily realized and the same effect can be obtained even in the case of three or more phases. stomach.

As is clear from the above explanation, according to the present invention,
As for the magnetic core of a chiyoke coil with a pair of windings wound in opposite directions, the initial magnetic permeability μ _i is practically 100,000 at a frequency of 10 KHz, and when the frequency is approximately
Approximately 100,000 or more in the frequency range below 10KHz,
Moreover, since it uses an amorphous magnetic alloy that has characteristics that satisfy μ _i ×=K in a frequency range of approximately 10 KHz or higher, it provides a noise filter that can be applied to a wide frequency range including the frequency range of 5 KHz to 150 KHz. There is an effect that can be done.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing the structure of an embodiment of the Chiyoke coil according to the present invention, Fig. 2 is a frequency characteristic diagram of the initial magnetic permeability of the amorphous magnetic alloy used as the magnetic core of the present invention, and Fig. Figure 4 is a frequency characteristic diagram of the absolute value of the impedance of the Chiyork coil shown in the figure, Figure 4 is an attenuation characteristic diagram of a noise filter using the Chiyork coil of the present invention and a conventional Chiyork coil,
This figure is an equivalent circuit diagram of the noise filter used to measure the attenuation characteristics shown in FIG. 4. 1...Amorphous magnetic alloy ribbon, 2...Magnetic core, 3,
4... Winding wire.

Claims (1)

[Scope of utility model registration request] In a noise filter noise filter coil in which a pair of windings are wound in opposite directions around a magnetic core, the magnetic core has an initial magnetic permeability of 10 KHz and substantially
100,000 in the frequency range of 10KHz or less, and has frequency characteristics that are inversely proportional to the frequency in the frequency range of approximately 10KHz or more.