JP2011129728A - Core for magnetic component, reactor, and core block - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a core for a magnetic component reducing a loss due to an eddy current to reduce a power ion loss, a reactor using the same, and a core block configuring the core for the magnetic component. <P>SOLUTION: The core 20 includes the plurality of core blocks 21 made of a magnetic material and a magnetic gap 22 made of a nonmagnetic material and disposed at least in one place. Each of the core blocks 21 positioned on the both sides of the magnetic gap 22 is a laminated core block configured by laminating a copper plate 51 and high-resistance layers 52 made of a magnetic material larger than the copper plate in electric resistance are disposed on uppermost and lowermost surfaces oriented in a laminating direction of the laminated core block. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a magnetic component core used for a power source of an electric vehicle or the like, a reactor using the same, and a core block constituting the magnetic component core.

  In recent years, automobiles that run by driving a motor with a DC power source, such as hybrid vehicles and fuel cell vehicles, have been developed due to environmental problems. In these automobiles, a DC-DC converter that boosts the voltage of a battery that is a DC power supply is mounted, and a reactor is a main part of the DC-DC converter.

  The reactor generally includes an annular core and a coil wound around a predetermined portion of the core. In an in-vehicle reactor, a core configured by assembling a plurality of core blocks is often employed due to restrictions on mounting space and manufacturing method. Further, in order to satisfy a predetermined electrical specification, a magnetic gap formed of a nonmagnetic member is often provided between two adjacent core blocks. By passing a current through the coil, an annular magnetic circuit is formed in the core.

  As the core block of the reactor, one formed by laminating steel plates as described in Patent Document 1 or one formed by a dust magnetic material as described in Patent Document 2 is adopted. ing.

  In a core having a magnetic gap and a core block formed by laminating steel plates as anisotropic magnetic bodies, magnetic flux spreads in the magnetic gap portion, so that a magnetic flux oblique to the laminating direction of the steel plates is generated. Eddy current is generated in the steel plate. The generation of this eddy current is concentrated on the uppermost surface and the lowermost surface in the laminating direction of the steel plates, and the loss due to this eddy current accounts for most of the iron loss generated in the core, causing local overheating and burnout accidents. In Non-Patent Document 1, the loss due to the eddy current is reduced by forming the core block in the stacking direction uppermost surface and the lowermost end at an oblique angle.

JP 2004-327479 A JP 2005-347626 A

Nakaaki Takaaki et al., “Reduction of Eddy Current Loss in Multi-Stage Core Reactor by Beveled Edge”, 2007 IEEJ National Conference 5-203

  As described in Non-Patent Document 1, if the end portions of the uppermost surface and the lowermost surface in the stacking direction of the core block are cut off obliquely, even if magnetic flux is generated in an oblique direction with respect to the stacking direction of the steel plates, Since the magnetic flux enters at an angle closer to the perpendicular to the steel plate, some eddy current loss can be reduced. However, since the amount of eddy current generated increases or decreases depending on the shape of the portion to be cut off, it is difficult to suppress eddy current, and there is a problem that loss cannot be sufficiently reduced. There is also a problem that the manufacturing cost is high because the processing is not easy.

  On the other hand, in the case of a core block formed of an isotropic magnetic material such as dust, the loss due to eddy current is small, but when comparing the power loss of the reactor using the core block, the steel plate is There exists a problem that it is large compared with the reactor using the core block formed by lamination | stacking.

  The present invention has been made in view of the above problems, and a purpose thereof is to reduce a loss due to an eddy current and reduce a power loss, a core for a magnetic component, a reactor using the same, and a magnetic component It is to provide a core block constituting the core.

  The core for a magnetic component according to the present invention has a plurality of core blocks that are magnetic materials and at least one magnetic gap that is made of a nonmagnetic material. The core blocks located on both sides of the magnetic gap are laminated core blocks each formed by laminating steel plates, and magnetism having a higher electric resistance than the steel plates is provided on the top and bottom surfaces in the lamination direction of the laminated core blocks. A high resistance layer made of a material is provided. (Claim 1)

  In this way, even if an oblique magnetic flux is generated on the uppermost and lowermost surfaces in the stacking direction of the core block, since it is a high-resistance layer made of a magnetic material having a high electrical resistance, eddy currents are generated. Can be suppressed.

  In the above-described magnetic component core, the thickness of the high resistance layer (the uppermost surface and the lowermost surface) is preferably 0.5 times or more the width of the magnetic gap. (Claim 2)

  If the thickness of the high-resistance layer is 0.5 times or more the width of the magnetic gap, the high-resistance layer may occupy a region where an oblique magnetic flux that causes eddy currents is present. it can. Therefore, the effect of suppressing the generation of eddy current is great.

  On the other hand, since the iron loss of the steel sheet is larger than the iron loss of the high resistance layer, the core loss of the entire core increases as the thickness of the high resistance layer increases. Therefore, the upper limit of the thickness of the high resistance layer is determined by the value of the iron loss of the materials (steel plate and high resistance layer) used for the core block.

Moreover, it is preferable that the resistivity of the said high resistance layer of the core for magnetic components mentioned above is 0.1 ohm * m or more. (Claim 3)
If the resistivity of the high resistance layer is 0.1 Ω · m or more, generation of eddy current can be more effectively suppressed. Note that the resistivity of the high resistance layer may be as high as long as it is made of a magnetic material.

  Moreover, it is preferable that the said high resistance layer of the core for magnetic components mentioned above is comprised with the powder magnetic body which consists of magnetic powder of a metal or an alloy, or a ferrite. (Claim 4)

  A magnetic powder made of magnetic powder of metal or alloy has a high saturation magnetic flux density among isotropic magnetic materials generally used. Therefore, the high resistance layer is made of magnetic powder made of magnetic powder of metal or alloy. By configuring the body, it is possible to reduce the size of the core and the reactor.

  In addition, since ferrite has a small loss among generally used isotropic magnetic materials, a core and a reactor with a small power loss can be provided if the high resistance layer is made of ferrite. Moreover, the cost is lower than other isotropic magnetic bodies.

  A reactor with low power loss can be supplied by extrapolating at least one coil to the above-described core for magnetic parts according to the present invention. (Claim 5)

The core block according to the present invention is configured by laminating steel plates, and a high resistance layer made of a magnetic material having an electric resistance larger than that of the steel plate is provided on the uppermost surface and the lowermost surface in the stacking direction. (Claim 6)
In this way, as described above, even if a magnetic flux in an oblique direction is generated on the uppermost and lowermost surfaces in the stacking direction of the core block, because it is a high resistance layer made of a magnetic material having a large electric resistance, Generation of eddy current can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the loss by the eddy current of the core for magnetic components and a core block can be reduced. Moreover, a reactor with small power loss can be supplied by extrapolating at least one coil to the magnetic component core of the present invention.

It is a top view of the reactor which concerns on this invention. It is a side view of the reactor which concerns on this invention. It is the schematic diagram which expanded and showed the surface of the powder magnetic body. It is sectional drawing which shows typically the state of the magnetic flux in a core. FIG. 5 is an enlarged view of a region “A” surrounded by a dotted line in FIG. 4. It is the perspective view which showed typically the state of the magnetic flux of the magnetic gap part vicinity in the core which concerns on this invention. It is the perspective view which showed typically the state of the magnetic flux near the magnetic gap part in the conventional core.

  Hereinafter, the present invention will be described based on embodiments. Note that the present invention is not limited to the following embodiments. Various modifications can be made to the following embodiments within the same and equivalent scope as the present invention.

  1 and 2 are a plan view and a side view of a reactor according to the present invention. However, for the sake of explanation, the coil is not shown, and only that region is represented by a two-dot chain line. The reactor 10 includes a core 20 configured in an annular shape and two coils 30 that are extrapolated at two locations of the core 20.

  As shown in FIG. 1, the core 20 has a substantially rectangular annular shape in plan view, and includes eight core blocks 21a and 21b made of a magnetic material and four magnetic gaps 22 made of a nonmagnetic material. ing. Here, the core has a substantially rectangular annular shape in a plan view, but it does not necessarily have an annular shape, and may have a rod shape (a substantially I shape in a plan view).

  As shown in FIG. 1, the core blocks 21 a located on both sides of the magnetic gap are configured by stacking steel plates 51, and the electrical resistance is higher than that of the steel plates 51 on the uppermost surface and the lowermost surface in the stacking direction. A high resistance layer 52 made of a large magnetic material is provided. Note that FIG. 1 schematically shows a laminated structure, and the number of steel plates 51 and high resistance layers 52 is not limited to the number in the drawing. Further, the stacking direction is not limited to the direction shown in FIG. In FIG. 1, the layers are stacked in the vertical direction on the plane of the plan view, but may be stacked in the vertical direction on the plane of the side view (FIG. 2), for example.

  The high resistance layer 52 is made of a magnetic material having an electric resistance larger than that of the steel plate 51, and can be formed of an isotropic magnetic material such as a dust magnetic material or ferrite.

  In the present embodiment, the core block 21 b that is not located on both sides of the magnetic gap 22 is configured by the dust magnetic material 55. However, the core block 21b may be made of an isotropic magnetic material other than the powder magnetic material such as ferrite, or may be formed of an anisotropic magnetic material such as a steel plate. Further, similarly to the core block 21 a located on both sides of the magnetic gap 22, a high resistance layer 52 made of a magnetic material having an electric resistance higher than that of the steel plate 51 may be provided on the uppermost surface and the lowermost surface in the stacking direction.

  As shown in FIG. 3, the dust magnetic body is composed of a plurality of dust particles 61 and an organic substance 67 interposed between the plurality of dust particles 61. Each of the dust particles 61 is joined by an organic substance 67 or joined by meshing unevenness of the dust particles 61. The dust particles 61 include metal magnetic particles 63 and an insulating coating 65 surrounding the surface of the metal magnetic particles 63.

  The metal magnetic particles 63 include, for example, iron (Fe), iron (Fe) -silicon (Si) alloy, iron (Fe) -nitrogen (N) alloy, iron (Fe) -nickel (Ni) alloy, iron (Fe) -carbon (C) alloy, iron (Fe) -boron (B) alloy, iron (Fe) -cobalt (Co) alloy, iron (Fe) -phosphorus (P) alloy, iron (Fe ) -Nickel (Ni) -cobalt (Co) alloy, iron (Fe) -aluminum (Al) -silicon (Si) alloy, and the like. The metal magnetic particles 63 may be a single metal or an alloy.

  The insulating coating 65 is formed by subjecting the metal magnetic particles 63 to phosphoric acid treatment. Preferably, the insulating coating 65 contains an oxide. As the insulating coating 65 containing this oxide, in addition to iron phosphate containing phosphorus and iron, manganese phosphate, zinc phosphate, calcium phosphate, aluminum phosphate, silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, etc. The oxide insulator can be used. The insulation coating 65 may be formed in one layer as shown in FIG. 3 or may be formed in multiple layers.

  Examples of the organic substance 67 include thermoplastic resins such as thermoplastic polyimide, thermoplastic polyamide, thermoplastic polyamideimide, polyphenylene sulfide, polyamideimide, polyethersulfone, polyetherimide, or polyetherethylketone, wholly aromatic polyester, or all Non-thermoplastic resins such as aromatic polyimides and higher fatty acids such as zinc stearate, lithium stearate, calcium stearate, lithium palmitate, calcium palmitate, lithium oleate or calcium oleate can be used. Moreover, these can also be mixed and used for each other.

  Ferrite is a general term for ceramics mainly composed of iron oxide. For example, in the case of spinel ferrite having a spinel crystal structure, it can be formed from manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), etc. as components other than iron oxide. Further, in the case of hexagonal ferrite having a magnetoplumbite-type hexagonal crystal structure, it can be formed of barium (Ba), strontium (Sr), lead (Pb), etc. as components other than iron oxide. In the case of garnet ferrite having a garnet type crystal structure, it can be formed from a rare earth element such as yttrium (Y) as a component other than iron oxide.

  Next, the present invention will be described in more detail based on examples.

Example 1
In the Example of this invention, the reactor was comprised similarly to FIG. The reactor 10 includes a core 20 configured in an annular shape and two coils 30. The core 20 includes six magnetic gaps 22, four core blocks 21 a positioned on both sides of the magnetic gap 22, and two core blocks 21 b not positioned on both sides of the magnetic gap 22. .

  As the magnetic gap 22, a ceramic plate is used, and its width is 2 mm. The core block 21a is formed by laminating 200 steel plates 51 each having a length of 10 mm, a width of 20 mm, and a thickness of 0.1 mm, and a dust magnetic material having a length of 10 mm, a width of 20 mm, and a thickness of 2 mm is formed on the top and bottom surfaces in the stacking direction. It is composed. Moreover, the core block 21b is comprised with the powder magnetic body, and has a planar-view substantially U-shaped form.

  The dust magnetic material used in the core blocks 21a and 21b is composed of the metal magnetic particles 63, the insulating coating 65, and the organic substance 67 as described above. In the embodiment of the present invention, the metal magnetic particles 63 include iron. The insulating coating 65 is made of iron phosphate and the organic substance 67 is made of thermoplastic polyimide.

  The thickness of the dust magnetic body (high resistance layer) of the core block 21 a is one time the width of the magnetic gap 22. The resistivity of the high resistance layer is 1 Ω · m.

  FIG. 4 is a cross-sectional view schematically showing the state of the magnetic flux 70 in the core 20 when a current is passed through the coil 35. The magnetic flux 70 proceeds in a smooth curve inside the core blocks 21a and 21b, which are magnetic materials, but spreads outward in the magnetic gap portion, which is a nonmagnetic material. FIG. 5 is an enlarged view of a region “A” surrounded by a dotted line in FIG. The magnetic flux 70 is ideally a straight straight line without the magnetic gap 22, but is curved on the surface side of the core block (the surface facing the coil 35 in FIG. 5) in order to spread by the magnetic gap 22. It has become. Therefore, in the region “B” in FIG. 5 in particular, magnetic flux in an oblique direction is generated with respect to the stacking direction (vertical direction in FIGS. 4 and 5).

  In the reactor configured as in Example 1, a high resistance layer (a dust magnetism) made of a magnetic material having an electric resistance higher than that of a steel plate is formed on the uppermost and lowermost layers in the stacking direction of the core blocks located on both sides of the magnetic gap. Therefore, in the region “B” in FIG. 5, the generation of eddy currents is suppressed even when magnetic flux is generated in an oblique direction with respect to the stacking direction.

  In the reactor configured as in Example 1, the loss was measured when an alternating current 30 A having a frequency of 10 kHz was passed through the coil 35. As a result, the loss was 100W.

(Comparative Example 1)
As a comparative example, the core block 21a in the first embodiment (core blocks located on both sides of the magnetic gap) is configured by stacking 240 steel plates 51 from the uppermost surface to the lowermost surface in the stacking direction. A reactor having the same configuration as in Example 1 was prepared.

  In the reactor configured as in Comparative Example 1, when a magnetic flux in an oblique direction with respect to the stacking direction is generated in the region “B” in FIG. 5, the reactor is stacked on the uppermost surface and the lowermost surface as shown in FIG. 7. Eddy currents are generated in the steel sheet.

  With a reactor configured as in Comparative Example 1, loss was measured under the same conditions as in Example 1. As a result, the loss was 90W.

  From the results of Example 1 and Comparative Example 1, it is shown that the loss in Example 1 using the core according to the present invention is smaller than the loss in Comparative Example 1, and the core according to the present invention has an eddy current. It has been confirmed that the loss due to the iron can be reduced and the iron loss can be reduced.

  The present invention is particularly excellent as a technique for reducing the loss due to eddy current in the magnetic component core and reducing the power iron loss of the reactor, and is therefore suitable for a power source for an electric vehicle or the like.

  10 reactors, 20 cores, 21a, 21b core blocks, 22 magnetic gaps, 30, 35 coils, 51 steel plates, 52 high resistance layers, 55 powdered magnetic bodies, 61 pressure divided particles, 63 metal magnetic particles, 65 insulation coating, 67 Organic matter, 70 magnetic flux, 80 eddy current

Claims (6)

A magnetic component core having a plurality of core blocks made of a magnetic material and at least one magnetic gap made of a non-magnetic material,
The core blocks located on both sides of the magnetic gap are each a laminated core block configured by laminating steel plates,
The magnetic component core according to claim 1, wherein a high resistance layer made of a magnetic material having an electric resistance larger than that of the steel plate is provided on an uppermost surface and a lowermost surface in the stacking direction of the stacked core block.   The magnetic component core according to claim 1, wherein a thickness of the high resistance layer is 0.5 times or more a width of the magnetic gap.   The magnetic component core according to claim 1, wherein the resistivity of the high resistance layer is 0.1 Ω · m or more.   The core for a magnetic component according to any one of claims 1 to 3, wherein the high resistance layer is made of a powder magnetic material made of a magnetic powder of metal or alloy, or ferrite.   A reactor, wherein at least one coil is extrapolated to the magnetic component core according to claim 1. A core block used for the magnetic component core according to any one of claims 1 to 4,
Constructed by laminating steel plates,
A core block characterized in that a high resistance layer made of a magnetic material having a larger electric resistance than the steel plate is provided on the uppermost surface and the lowermost surface in the stacking direction.

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