JPH10163046A - Noise filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the characteristics and lessen the leakage flux by forming one coil round one of a center and outside the magnetic legs of a twin slot core and the other coil round the center and one outside magnetic legs together. SOLUTION: The noise film has a twin slot core 1 composed of combined ferrite EE cores with a magnetic gap at a center magnetic leg 3. A first coil 6 is wound round the center magnetic leg 3 of the core 1 and one outside magnetic legs 2a together. A second coil 7 is wound round the center magnetic leg 3 of the core 1 are the other outside magnetic legs 2b together. The sectional area ratio of the center leg 3 of the core 1: outside legs 2a, 2b: common magnetic leg 4 is 1:0.4-0.6:0.4-0.6. It is composed, using combined square cores and I type cores.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise filter used for consumer or industrial electronic equipment.

[0002]

2. Description of the Related Art As a conventional noise filter used for a power supply line, the one shown in FIGS. 16 and 17 is known. FIGS. 16 and 17 are schematic diagrams of a magnetic circuit configuration of a conventional noise filter. In the figure, 30 is a square-shaped core, 31 is an I-shaped core, 32, 3
3 is a coil, 34 is a UU core, 35 is an EI core, 3
6, 37 are coils, A is AC line current, B is normal mode noise, C is common mode noise, φA is magnetic flux generated by AC line current, φB is magnetic flux generated by normal mode noise, φC is common mode noise The generated magnetic flux is shown.

A conventional noise filter having a magnetic circuit configuration shown in FIG. 16 has a square-shaped core 30 made of a magnetic material having a high magnetic permeability such as a ferrite material on the outside, and a dust core material or the like provided on a central magnetic leg. A different type of magnetic material having a high magnetic flux saturation density
The coils 32 and 33 are wound around each of the side magnetic legs of the square-shaped core 30 by using the sun-shaped core combined with the square-shaped core 31.

At this time, the magnetic flux φA generated for the AC line current A winds the respective coils 32 and 33 so as to be in the direction shown by the solid line. As a result, the magnetic flux φA generated by the AC line current A flows through the magnetic path in which the I-shaped magnetic core 31 having excellent magnetic saturation characteristics is present, so that the magnetic flux φA can be prevented from causing magnetic saturation in use.

In this state, for the component of the normal mode noise B, the magnetic flux φB is generated in the direction shown by the dotted line, and the normal mode inductance can be secured.

Further, with respect to the component of the common mode noise C, a magnetic flux φC is generated in the direction indicated by the dashed line, and the common mode inductance can be secured. Here, the magnetic flux φC is the I-shaped magnetic core 31 of the central magnetic leg having a high magnetic resistance.
Therefore, a large inductance value is obtained with respect to the common mode noise C component since the current flows through the outer square-shaped magnetic core 30 without flowing.

As described above, the conventional noise filter having the magnetic circuit shown in FIG. 16 can obtain a noise attenuating effect on common and normal mode noise with one component.

A conventional noise filter having a magnetic circuit configuration shown in FIG. 17 comprises a UU-shaped core 34 made of a magnetic material having a high magnetic permeability such as a ferrite material and a magnetic material having a high magnetic flux saturation density such as a dust core material. Combining the EI type magnetic core 35,
Coils 36 and 37 so as to straddle the three magnetic cores 34 and 35
Is wound.

At this time, the magnetic flux φA generated by the AC line current A is wound around the coils 36 and 37 in the directions indicated by solid lines in the respective magnetic cores 34 and 35. As a result, the EI type magnetic core 35 made of a magnetic material having a high magnetic flux saturation density has excellent magnetic saturation characteristics, so that magnetic saturation in use of the magnetic flux φA can be prevented.

On the other hand, in the UU type magnetic core 34 made of a magnetic material having a high magnetic permeability, the magnetic flux φA is generated in a direction in which the magnetic flux φA cancels out in this magnetic path, so that magnetic saturation does not occur in use.

In this state, with respect to the component of normal mode noise B, a magnetic flux φB is generated in a direction indicated by a dotted line in the EI type magnetic core 35 made of a magnetic material having a high magnetic flux saturation density, and the normal mode inductance is secured. be able to.

Further, with respect to the component of the common mode noise C, a magnetic flux φC is generated in the direction indicated by a dashed line within the UU-shaped magnetic core 34 made of a magnetic material having a high magnetic permeability, and the common mode inductance can be secured. . Here, since the magnetic core used is made of a magnetic material having a high magnetic permeability, a large inductance value is obtained for the common mode noise C component.

As described above, the conventional noise filter having the magnetic circuit shown in FIG. 17 can obtain a noise attenuating effect on common and normal mode noise with one component.

[0014]

However, any conventional noise filter can cope with the common and normal noise B and C components with one component. However, in the configuration shown in FIG. 17, two completely independent noise filters are provided. Since the magnetic cores 34 and 35 are required, an increase in cost cannot be avoided. Further, in terms of manufacturing, the use of the two types of magnetic cores 34 and 35 has a problem that the process becomes complicated.

On the other hand, the configuration shown in FIG. 16 is a relatively simple configuration only by combining one kind of square core 30 and an I-shaped core 31 having a simple shape. Since the common and the normal mode inductance are combined in the magnetic core, the magnetic path of the normal mode in the common mode is a magnetic flux φA generated by the AC line current A.
However, there is a problem that the magnetic flux becomes a path magnetic path and the magnetic saturation characteristics are greatly deteriorated.

The I-shaped magnetic core 31 made of a magnetic material having a high magnetic flux saturation density has a completely exposed structure despite the generation of leakage flux. It is also a problem.

Further, in the conventional noise filter shown in FIGS. 16 and 17, in order to constitute a specification for changing the balance between the inductance of the common mode and the normal mode, the sectional area and the material of the magnetic material must be changed. There was a problem that it was practically impossible to respond to such a specification change.

An object of the present invention is to eliminate the above-mentioned conventional disadvantages and to provide a noise filter having stable characteristics and low leakage flux.

[0019]

A noise filter according to the present invention comprises a sun-shaped magnetic core, a first coil, and a second coil, and one of the coils is a sun-shaped magnetic core. And a coil wound around at least one of the center magnetic leg and both outer magnetic legs, and the other coil wound over either the center magnetic leg or both outer magnetic legs. It is.

With this configuration, the reliability is high,
High quality can be obtained at low cost.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a sun-shaped magnetic core, a first coil and a second coil, and one of the coils is a central magnetic core of the sun-shaped magnetic core. And a coil wound around at least one of the leg and both outer magnetic legs, and the other coil wound around one of the center magnetic leg and both outer magnetic legs. The noise attenuating effect on the noise is obtained, and the leakage flux can be suppressed at low cost.

According to a second aspect of the present invention, the first coil is wound so as to straddle the central magnetic leg and one of the outer magnetic legs,
Since the second coil is wound so as to straddle the center magnetic leg and the other outer magnetic leg, a large common and normal mode inductance can be obtained.

According to a third aspect of the present invention, in addition to the configuration of the second aspect, both the first coil and the second coil are wound around the outer magnetic leg more than the central magnetic leg. By changing the turns ratio of the coil, it is possible to flexibly cope with the change of the inductance specification.

According to a fourth aspect of the present invention, the first coil is wound around one of the outer magnetic legs, and the second coil is wound around the central magnetic leg and the one outer magnetic leg around the first coil. In this configuration, the magnetic saturation characteristics can be prevented from greatly deteriorating.

According to a fifth aspect of the present invention, the first coil is wound only on the center magnetic leg, and the second coil is wound on the center magnetic leg and one of the outer magnetic legs. With this configuration, a large inductance can be obtained and the leakage flux can be suppressed.

According to the sixth aspect of the present invention, an EE-shaped magnetic core is combined as a sun-shaped magnetic core. Since the magnetic core is made of one kind of material, the cost can be reduced and the manufacturing process can be simplified.

The seventh aspect of the present invention uses a combination of a square-shaped magnetic core and an I-shaped magnetic core as a sun-shaped magnetic core, which also facilitates assembly at low cost.

The eighth aspect of the present invention is a combination of an I-shaped core and a shape in which a common magnetic leg of a square-shaped core is extended to one side as a sun-shaped core. Assembly is easy at low cost.

According to the ninth aspect of the present invention, a square-shaped magnetic core and a square-shaped magnetic core are combined as a sun-shaped magnetic core, and this configuration is also easy to assemble at low cost.

According to a tenth aspect of the present invention, the ratio of the cross-sectional area of the center magnetic leg, the cross-sectional areas of both outer magnetic legs, and the cross-sectional area of the common magnetic leg of the sun-shaped magnetic core is 1: 0.4 to 0.6. : 0.4 to 0.6, the magnetic flux in the magnetic core can be made uniform, and the size and cost of the magnetic core can be reduced.

According to an eleventh aspect of the present invention, in addition to the configuration of the fifth aspect, the cross-sectional area of one outer magnetic leg around which the second coil is wound, and the first coil and the second coil are formed. The ratio of the cross-sectional area of the wound center magnetic leg, the cross-sectional area of the other outer magnetic leg where the coil is not wound, and the cross-sectional area of the common magnetic leg is 1: 0.56.
-1: 0.25-0.66: 0.56-1, the magnetic flux in the magnetic core can be made uniform, and the size and cost of the magnetic core can be reduced.

Hereinafter, specific embodiments of the present invention will be described. (Embodiment 1) Embodiment 1 of the present invention will be described below with reference to the drawings. 1 to 5 showing Embodiment 1 of the present invention will not be described.

FIGS. 1, 2, 4 and 5 are schematic views showing a magnetic circuit configuration of a noise filter according to the first embodiment of the present invention, which can cope with normal and common noise components with one component. FIG. 3 shows the result of simulating the magnetic flux density distribution amount of the magnetic core of the noise filter of the present invention by an index.

In the figure, reference numeral 1 denotes a sun-shaped magnetic core, 2a denotes one outer magnetic leg of the sun-shaped magnetic core 1, 2b denotes the other outer magnetic leg of the sun-shaped magnetic core 1, and 3 denotes a sun-shaped magnetic core 1. Central magnetic leg,
4 is a common magnetic leg of the sun-shaped magnetic core 1, 5 is a magnetic gap,
6, 6a is the first coil, 7, 7a is the second coil, 8
Indicates a square-shaped magnetic core, and 9 indicates an I-shaped magnetic core.

The noise filter shown in FIG. 1 will be described below. The noise filter shown in FIG. 1 is composed of a sun-shaped magnetic core 1 formed by combining an EE type magnetic core made of a ferrite material having a high magnetic permeability with a magnetic gap 5 provided in a center magnetic leg 3. Is wound so as to straddle the first coil 6 on the center magnetic leg 3 and one outer magnetic leg 2a, and the second coil 7 is further wound on the center magnetic leg 3 of the sun-shaped magnetic core 1 and the other outer magnetic leg 2b. Wind over the wire.

In the noise filter shown in FIG. 2, in the magnetic circuit configuration shown in FIG. 1, the first and second coils 6, 7 are respectively connected to the center magnetic leg 3 and the outer magnetic legs 2a, 2b of the sun-shaped magnetic core 1.
The first and second coils 6 and 7 that are wound so as to extend over the outer magnetic legs 2a and 2b at the same time.
a, 7a.

At this time, the magnetic flux φA generated by the AC line current A winds the first and second coils 6, 7, 6a, 7a so as to be in the directions shown by the solid lines.

As a result, the magnetic flux φA generated in the outer magnetic legs 2a and 2b due to the AC line current A cancels each other, and the magnetic flux φA generated in the central magnetic leg 3 is
Since the magnetic flux flows through the magnetic path in which the central magnetic leg 3 having excellent magnetic saturation characteristics exists, magnetic saturation in the use state with respect to the magnetic flux φA can be prevented.

In this state, for the component of the normal mode noise B, the magnetic flux φB is generated in the direction shown by the dotted line, and the normal mode inductance can be secured.

Further, with respect to the component of the common mode noise C, the magnetic flux φC is generated in the direction indicated by the dashed line, and the common mode inductance can be secured. Here, since the magnetic flux φC does not flow through the central magnetic leg 3 having a high magnetic resistance, but flows through the outer magnetic legs 2a and 2b and the common magnetic leg 4, a large inductance value is obtained for the common mode noise C component.

As described above, FIGS. 1 and 2 of the first embodiment
The noise filter having the magnetic circuit shown in (1) can obtain a noise attenuating effect on common and normal mode noise with one component as in the related art.

In terms of characteristics, the same day-shaped magnetic core 1
Although the common mode and the normal mode inductance are combined, the magnetic path of the normal mode in the common mode is unlikely to be a path circuit of the magnetic flux φA generated by the AC line current A as in the related art. Significant deterioration is suppressed.

The first and second coils 6, 6a and 7, 7a wound around the center magnetic leg 3 and the outer magnetic legs 2a, 2b of the sun-shaped magnetic core 1 are composed of the center magnetic leg 3, This is because the magnetic circuit in the normal mode hardly becomes a magnetic flux path circuit because of the magnetic circuit configuration in which the magnetic flux φA is generated from the magnetic field.

A leakage flux is generated from the magnetic gap 5 provided for improving the magnetic saturation characteristics. However, since the core has a core-type winding structure completely covered by a coil, the leakage flux is reduced. Suppression is also possible.

On the other hand, the structure is constituted by one kind of sun-shaped magnetic core 1, so that the cost can be reduced and the manufacturing process can be simplified.

Further, in order to configure a specification for changing the balance between the inductance of the common mode and the normal mode by configuring the winding structure as shown in FIG. 2, the first coil 6, 6a and the second coil 7 , 7a wound around the center magnetic leg 3 and the outer magnetic legs 2a, 2b of the sun-shaped magnetic core 1, and the outer magnetic legs 2a, 2b.
It becomes possible only by changing the ratio of the number of turns of the coils 6a and 7a wound only on the coil 2b.

Therefore, it is not necessary to change the cross-sectional area and the material of the magnetic material used as in the prior art, and there is an advantage that the change in the balance specification of the inductance can be flexibly performed.

Next, FIG. 3 simulates the distribution of the magnetic flux density flowing in the magnetic path of the sun-shaped magnetic core 1 of the first embodiment, and shows the result as an index.

Here, the ratio of the cross-sectional area of the center magnetic leg 3 of the sun-shaped magnetic core 1: the cross-sectional area of the outer magnetic legs 2 a and 2 b: the cross-sectional area of the common magnetic leg 4 is 2: 1: 1 and the magnetic flux density distribution is assumed. A quantity simulation was performed.

As a result, from the magnetic flux density distribution index of each magnetic leg, the cross-sectional area of the center magnetic leg 3 of the sun-shaped magnetic core 1: the cross-sectional area of both outer magnetic legs 2 a and 2 b: the cross-sectional area of the common magnetic leg 4 The ratio of 1: 0.4 to 0.6: 0.4 to 0.6 constitutes a magnetic core, whereby the magnetic flux in the magnetic core in the first embodiment is made uniform, and It has been clarified that the size and cost can be reduced.

That is, the noise filter formed by using the magnetic core can be reduced in size and cost.

In the first embodiment, ferrite is described as an example of the material of the L-shaped magnetic core 1. However, other magnetic core materials may be used. This is the same in the following embodiments.

Further, as shown in FIGS. 4 and 5, without forming the magnetic gap 5 in the central magnetic leg 3 of the sun-shaped magnetic core 1,
A square-shaped magnetic core made of a magnetic material having a high magnetic permeability such as a ferrite material 8
It goes without saying that the same effect can be obtained by combining and using a different type of I-shaped magnetic core 9 made of a magnetic material having a high magnetic flux saturation density such as a dust core.

(Embodiment 2) FIGS. 6 to 9 show schematic diagrams of a magnetic circuit configuration of a noise filter according to Embodiment 2 of the present invention which can cope with normal and common noise components with one component. ing.

In the figure, reference numeral 10 denotes a first coil, 1
1, 11a indicates a second coil. The noise filter shown in FIG. 6 is provided with a first magnetic pole 2a of a sun-shaped magnetic core 1 made of a ferrite material having a high magnetic permeability in which a magnetic gap 5 is provided in a central magnetic leg 3. The coil 10 is wound, and the second coil 11 is further wound so as to straddle the one outer magnetic leg 2 a around which the first coil 10 of the sun-shaped magnetic core 1 is wound and the center magnetic leg 3.

In the noise filter shown in FIG. 7, in the magnetic circuit configuration shown in FIG. 6, the second coil extends over the outer magnetic leg 2a around which the first coil 10 of the sun-shaped magnetic core 1 is wound and the center magnetic leg 3. The coil 11a that winds only the outer magnetic leg 2a is provided at the same time as the coil 11 that winds.

At this time, the first and second magnetic fluxes φA generated by the AC line current A are directed in the directions indicated by solid lines.
Are wound, respectively.

As a result, the magnetic fluxes φA generated in one outer magnetic leg 2a by the AC line current A cancel each other, and
The magnetic flux φA generated in the center magnetic leg 3 flows through the magnetic path in which the center magnetic leg 3 having the magnetic gap 5 and having excellent magnetic saturation characteristics exists, so that the magnetic flux φA can be prevented from causing magnetic saturation in use. .

In this state, the magnetic flux φB is generated in the direction indicated by the dotted line with respect to the component of the normal mode noise B, and the normal mode inductance can be secured.

Further, for the component of the common mode noise C, the magnetic flux φC is generated in the direction indicated by the dashed line, and the common mode inductance can be secured. here,
Since the magnetic flux φC does not flow through the central magnetic leg 3 having a high magnetic resistance, but flows through the outer magnetic legs 2a and 2b and the common magnetic leg 4, a large inductance value is obtained for the common mode noise C component.

As described above, FIGS. 6 and 7 of the second embodiment
The noise filter having the magnetic circuit shown in (1) can obtain a noise attenuating effect on common and normal mode noise with one component as in the related art.

From the viewpoint of characteristics, the first coil 10 and the second coils 11 and 11a have an upper and lower winding structure with high coupling, and the magnetic flux φA is canceled by one outer magnetic leg 2a. The magnetic path in the normal mode is unlikely to be a path circuit for the magnetic flux φA generated by the AC line current A as in the conventional example, and a large deterioration of the magnetic saturation characteristic is suppressed.

In particular, the second embodiment differs from the system shown in the first embodiment in that the first coil 10 and the second coil 11,
Since the winding structure of 11a has a higher coupling, the suppression of the magnetic saturation characteristic is more effective.

This means that the common mode inductance value can be increased.

Although a leakage flux is generated from the magnetic gap 5 provided for improving the magnetic saturation characteristic, the magnetic gap 5 is completely covered with the second coil 11 so as to form a core-shaped winding structure. Leakage flux can be suppressed.

On the other hand, in terms of structure, one kind of day-shaped magnetic core 1
, The cost can be reduced and the manufacturing process can be simplified.

Further, in order to configure a specification for changing the balance between the inductance of the common mode and the normal mode by configuring the winding structure as shown in FIG. It becomes possible only by changing the winding ratio of the coil 11 wound around the leg 3 and one outer magnetic leg 2a and the coil 11a wound only on the outer magnetic leg 2a.

Therefore, it is not necessary to change the cross-sectional area and the material of the magnetic material used as in the prior art, and there is an advantage that the change in the balance specification of the inductance can be flexibly performed.

Next, a simulation of the amount of magnetic flux density distribution flowing in the magnetic path of the sun-shaped magnetic core 1 used in the same manner as in the first embodiment of the present invention was performed. Here, the ratio of the cross-sectional area of the central magnetic leg 3 of the sun-shaped magnetic core 1: the cross-sectional area of the outer magnetic legs 2 a and 2 b: the cross-sectional area of the common magnetic leg 4 is also the same as in the first embodiment in which the ratio is 2: 1: 1. The simulation of the magnetic flux density distribution was performed as follows.

As a result, the same result as that of the first embodiment shown in FIG. 3 was obtained in the second embodiment. Accordingly, the ratio of the cross-sectional area of the center magnetic leg 3 of the sun-shaped magnetic core 1: the cross-sectional area of the outer magnetic legs 2 a and 2 b: the cross-sectional area of the common magnetic leg 4 is 1: 0.4 to 0.6: 0.4. It has been clarified that by configuring the magnetic core within the range of 0.6, the magnetic flux in the magnetic core according to the second embodiment can be made uniform, and the magnetic core can be reduced in size and cost.

That is, the noise filter formed by using this magnetic core can be reduced in size and cost.

Further, as shown in FIGS. 8 and 9, the magnetic gap 5 is not formed on the center magnetic leg 3 of the sun-shaped magnetic core 1.
A square-shaped magnetic core made of a magnetic material having a high magnetic permeability such as a ferrite material 8
It goes without saying that the same effect can be obtained by combining and using a different type of I-shaped magnetic core 9 made of a magnetic material having a high magnetic flux saturation density such as a dust core.

(Embodiment 3) FIGS. 10, 12, and 14
(A), (b) and FIGS. 15 (a), (b) are schematic diagrams of a magnetic circuit configuration of a noise filter according to a third embodiment of the present invention, which can cope with normal and common noise components with one component. FIG. 11 is an assembly diagram of FIG. 10, and FIG. 13 is a graph showing the results of simulation of the magnetic flux density distribution of the magnetic core of the noise filter of the present invention.

In the figure, reference numeral 12 denotes a sun-shaped magnetic core;
Is an outer magnetic leg of the sun-shaped core 12, 14 is a center magnetic leg of the sun-shaped core 12, 15 is another outer magnetic leg of the sun-shaped core 12, and 16 is a common magnetic leg of the sun-shaped core 12. , 17 are a first coil, 18 and 18a are second coils, 19 is a sun-shaped core having a partially opened magnetic path, 20 is an I-shaped core,
Numeral 1 denotes a square-shaped core, and numeral 22 denotes a square-shaped core.

The noise filter shown in FIG. 10 is provided on the center magnetic leg 14 of the sun-shaped magnetic core 12 made of a ferrite material having a high magnetic permeability in which a magnetic gap 5 is provided on one outer magnetic leg 13. , The first coil 17 is wound, and the second coil 18 is wound on the first
Magnetic leg 14 and the magnetic gap 5
Is wound so as to straddle one of the outer magnetic legs 13 provided with.

More specifically, as shown in FIG. 11, the bobbin on which the first coil 17 is wound is inserted and fitted into the bobbin on which the second coil 18 is wound, and thereafter, a bobbin of the EE type is used. The figure-shaped magnetic core 12 is inserted and completed. Here, each winding employs a split winding in order to improve characteristics in a high frequency region.

In the noise filter shown in FIG. 12, the second coil in the magnetic circuit configuration shown in FIG.
Simultaneously with the coil 18 wound so as to straddle the center magnetic leg 14 and the outer magnetic leg 13 wound with the second first coil 17,
A coil 18a for winding only the center magnetic leg 14 is provided.

At this time, the first and second magnetic fluxes φA generated by the AC line current A are directed in the directions indicated by the solid lines.
Are wound, respectively.

As a result, the magnetic flux φA generated in the center magnetic leg 14 due to the AC line current A cancels each other, and the magnetic flux φA generated in the one outer magnetic leg 13 has the magnetic gap 5 and the outer magnetic leg having excellent magnetic saturation characteristics. Since the magnetic flux flows through the magnetic path in which the magnetic flux 13 exists, it is possible to prevent the magnetic flux φA from causing magnetic saturation in a use state.

In this state, the magnetic flux φB is generated in the direction indicated by the dotted line with respect to the component of the normal mode noise B, and the normal mode inductance can be secured.

Further, with respect to the component of the common mode noise C, the magnetic flux φC is generated in the direction shown by the dashed line, and the common mode inductance can be secured. Here, the magnetic flux φC does not flow through the outer magnetic leg 13 having a high magnetic resistance,
Since the magnetic flux flows through the center magnetic leg 14, the common magnetic leg 16, and the other outer magnetic leg 15, a large inductance value is obtained for the common mode noise C component.

As described above, the noise filter having the magnetic circuit shown in FIGS. 10 and 12 according to the third embodiment can obtain a noise attenuating effect on common and normal mode noise with one component as in the related art.

From the viewpoint of characteristics, the first coil 17 and the second coils 18 and 18a have an upper and lower winding structure with high coupling, and the magnetic flux φA is canceled by the center magnetic leg 14, so that the common mode is different from the conventional example. Normal mode magnetic path is AC
It is difficult to form a path circuit for the magnetic flux φA generated by the line current A, and a large deterioration of the magnetic saturation characteristic is suppressed.

In particular, as compared with the system described in the second embodiment, the length of the magnetic path forming the common mode inductance is shorter, so that a larger inductance can be secured.

Although a leakage flux is generated from the magnetic gap 5 provided for improving the magnetic saturation characteristic, the leakage flux is suppressed because the core-type winding structure is completely covered with the coil 18. Is also possible.

On the other hand, in terms of structure, one kind of day-shaped magnetic core 1
2, the cost can be reduced and the manufacturing process can be simplified.

Further, in order to configure a specification for changing the balance between the inductance of the common mode and the normal mode by configuring the winding structure as shown in FIG.
It is possible only by changing the winding ratio of the coil 18 wound around the central magnetic leg 14 and the outer magnetic leg 13 of the sun-shaped magnetic core 12 and the coil 18a wound only on the central magnetic leg 14 Becomes Therefore, it is not necessary to change the cross-sectional area and the material of the magnetic material used as in the related art, and there is an advantage that it is possible to flexibly cope with the change of the inductance specification.

Next, FIG. 13 simulates the amount of distribution of the magnetic flux density flowing in the magnetic path of the sun-shaped magnetic core 12 according to the third embodiment described above, and the result is shown as an index. Here, the ratio of the cross-sectional area of one outer magnetic leg 13 of the sun-shaped magnetic core 12: the cross-sectional area of the central magnetic leg 14: the cross-sectional area of the other outer magnetic leg 15: the cross-sectional area of the common magnetic leg 16 is 2: 1. 0.5: 1: 1.5.

As a result, the cross-sectional area of one outer magnetic leg 13 of the sun-shaped magnetic core 12: the cross-sectional area of the central magnetic leg 14: the cross-sectional area of the other outer magnetic leg 15 from the magnetic flux density distribution index of each magnetic leg. : The ratio of the cross-sectional area of the common magnetic leg 16 is 1: 0.56 to 1:
By configuring the magnetic core within the range of 0.25 to 0.66: 0.56 to 1, the magnetic flux in the magnetic core according to the third embodiment is made uniform, and the core is reduced in size and cost is reduced. It was clarified that this could be achieved. That is, it is possible to reduce the size and cost of the noise filter configured using the magnetic core.

Further, as shown in FIGS. 14 and 15, a magnetic gap 5 is not formed in the outer magnetic leg 13 of the sun-shaped magnetic core 12, and a part of a magnetic material having a high magnetic permeability such as a ferrite material is opened. The I-shaped core 20 made of a magnetic material having a high magnetic flux saturation density, such as a powdered iron core, or a square-shaped magnetic core 21 made of a magnetic material having a high magnetic permeability, such as a ferrite material, is used. It goes without saying that the same effect can be obtained by combining and using a U-shaped magnetic core 22 made of a magnetic material having a high magnetic flux saturation density such as a dust core.

[0091]

As described above, according to the noise filter of the present invention, in a noise filter comprising a sun-shaped magnetic core and a first coil and a second coil, one of the coils is formed by the center magnetic leg of the sun-shaped magnetic core. And at least one of the outer magnetic legs, and the other coil is wound so as to straddle either the center magnetic leg or the outer magnetic legs of the sun-shaped core. And the common magnetic leg can secure common mode inductance, and the magnetic path consisting of the central magnetic leg, common magnetic leg, and outer magnetic leg can secure normal mode inductance. Is obtained.

Further, from the characteristic point of view, despite the fact that common and normal mode inductances are combined in the same magnetic core, the magnetic path of the normal mode in the common mode becomes a magnetic flux path circuit for the AC line current. Therefore, it is possible to suppress large deterioration of the magnetic saturation characteristics.

Further, it is possible to change the balance between the inductances of the common mode and the normal mode simply by changing the turns ratio of the coils.

Further, the magnetic core can be reduced in size and cost.
It is possible to reduce the size and cost of the noise filter configured using this magnetic core.

As described above, a highly reliable noise filter can be provided at low cost and with high quality, which is of great industrial value.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a magnetic circuit configuration of a noise filter according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of a magnetic circuit configuration of another noise filter.

FIG. 3 is a diagram showing a simulation result of a magnetic flux density distribution amount flowing in a magnetic path of a magnetic core of the noise filter, and showing the result as an index.

FIG. 4 is a schematic diagram of a magnetic circuit configuration of another noise filter.

FIG. 5 is a schematic diagram of a magnetic circuit configuration of another noise filter.

FIG. 6 is a schematic diagram of a magnetic circuit configuration of a noise filter according to a second embodiment of the present invention.

FIG. 7 is a schematic diagram of a magnetic circuit configuration of another noise filter.

FIG. 8 is a schematic diagram of a magnetic circuit configuration of another noise filter.

FIG. 9 is a schematic diagram of a magnetic circuit configuration of another noise filter.

FIG. 10 is a schematic diagram of a magnetic circuit configuration of a noise filter according to a third embodiment of the present invention.

FIG. 11 is an assembly diagram of the noise filter.

FIG. 12 is a schematic diagram of a magnetic circuit configuration of another noise filter.

FIG. 13 is a diagram showing a simulation result of a magnetic flux density distribution amount flowing in a magnetic path of a magnetic core of the noise filter, and showing the result as an index.

FIG. 14 is a schematic diagram of a magnetic circuit configuration of another noise filter.

FIG. 15 is a schematic diagram of a magnetic circuit configuration of another noise filter.

FIG. 16 is a schematic diagram of a magnetic circuit configuration of a conventional noise filter.

FIG. 17 is a schematic diagram of a magnetic circuit configuration of a conventional noise filter.

[Explanation of symbols]

 1 day-shaped magnetic core 2a one outer magnetic leg 2b the other outer magnetic leg 3 central magnetic leg 4 common magnetic leg 5 magnetic gap 6,6a first coil 7,7a second coil 8 square-shaped core 9 I-shaped Magnetic core 10 First coil 11, 11a Second coil 12 Sun-shaped magnetic core 13 One outer magnetic leg 14 Central magnetic leg 15 The other outer magnetic leg 16 Common magnetic leg 17 First coil 18, 18a Second coil 19 Sun-shaped core with a partially open magnetic path 20 I-shaped core 21 B-shaped core 22 U-shaped core

Claims (11)

[Claims] 1. A sun-shaped core, a first coil, and a second coil, wherein one of the coils is at least one of a center magnetic leg and both outer magnetic legs of the sun-shaped core. And a coil wound so that the other coil extends over one of the center magnetic leg and both outer magnetic legs. 2. The method according to claim 1, wherein the first coil is wound so as to straddle the central magnetic leg and one outer magnetic leg, and the second coil is wound so as to straddle the central magnetic leg and the other outer magnetic leg. Item 1
The noise filter according to 1. 3. The noise filter according to claim 2, wherein both the first coil and the second coil are wound around the outer magnetic leg more than the central magnetic leg. 4. A first coil is wound around one of the outer magnetic legs, and a second coil is wound around the center magnetic leg and the one outer magnetic leg around which the first coil is wound. Claim 1
The noise filter according to 1. 5. The noise according to claim 1, wherein the first coil is wound around the center magnetic leg only, and the second coil is wound so as to straddle the center magnetic leg and one of the outer magnetic legs. filter. 6. The noise filter according to claim 1, wherein an EE-shaped magnetic core is combined as the sun-shaped magnetic core. 7. The noise filter according to claim 1, wherein a square-shaped core and an I-shaped core are combined as the sun-shaped core. 8. The noise filter according to claim 1, wherein the I-shaped magnetic core is combined with an I-shaped magnetic core having a common magnetic leg extending to one side as a sun-shaped magnetic core. 9. The noise filter according to claim 1, wherein a square-shaped core and a square-shaped core are combined as the sun-shaped core. 10. The ratio of the cross-sectional area of the center magnetic leg, the cross-sectional areas of both outer magnetic legs, and the cross-sectional area of the common magnetic leg of the sun-shaped magnetic core is 1: 0.4.
The noise filter according to claim 1, wherein -0.6: 0.4-0.6. 11. A cross-sectional area of one outer magnetic leg around which the second coil is wound, a cross-sectional area of a center magnetic leg around which the first coil and the second coil are wound, and the other of which the coil is not wound The ratio of the cross-sectional area of the outer magnetic leg to the cross-sectional area of the common magnetic leg is 1: 0.56.
The noise filter according to claim 5, wherein the ratio is set to １ ： 1: 0.25 to 0.66: 0.56 to 1.