Patent Application
20230298801
The present disclosure relates to a reactor, a converter, and a power conversion device.
This application claims a priority based on Japanese Patent Application No. 2020-141155 filed on Aug. 24, 2020, all the contents of which are hereby incorporated by reference.
Constituent components of a converter to be installed in a vehicle such as a hybrid or electric vehicle include a reactor. The reactor is provided with a coil and a magnetic core.
A reactor of the present disclosure includes a coil and a magnetic core, the magnetic core including a first core and a second core formed into a θ shape by being combined in an X direction, the first core including a first end core part, at least a part of a middle core part and at least parts of both side core parts including a first side core part and a second side core part, the second core including a second end core part, a remaining part of the middle core part and remaining parts of the first and second side core parts, the first end core part facing a first end surface of the coil, the second end core part facing a second end surface of the coil, the middle core part being arranged inside the coil, the first and second side core parts being arranged outside the coil to sandwich the middle core part, a relative magnetic permeability of the second core being higher than that of the first core, each of the first and second side core parts of the first core having a tip surface facing the second core, a surface of the second core having facing surfaces facing the tip surfaces, an outer side edge of the facing surface being located inwardly of that of the tip surface in a Y direction and an inner side edge of the facing surface and that of the tip surface being substantially aligned in the Y direction when the magnetic core is viewed from a Z direction, a width in the Y direction of the facing surface being shorter than that of the tip surface, the X direction being a direction along an axial direction of the middle core part, the Y direction being a parallel direction of the middle core part, the first side core part and the second side core part, and the Z direction being a direction orthogonal to both the X direction and the Y direction.
A converter of the present disclosure includes the reactor of the present disclosure.
A power conversion device of the present disclosure includes the converter of the present disclosure.
In terms of reducing the weight of a reactor, a weight reduction of a magnetic core is required.
Generally, in an E-E type magnetic core, two E-shaped core pieces are symmetrically arranged. The both core pieces are made of the same material and have the same shape and size. If the entire magnetic core is reduced in size, specifically, if the both core pieces are reduced in size for the weight reduction of the magnetic core, electromagnetic performance of a reactor may be affected. Further, if the entire magnetic core is reduced in size, there is a concern for a loss increase. Therefore, it is desired to realize the weight reduction of the magnetic core while maintaining the electromagnetic performance. An inductance can be, for example, cited as the electromagnetic performance.
Accordingly, one object of the present disclosure is to provide a reactor which can be reduced in weight. Another object of the present disclosure is to provide a converter provided with the above reactor. Still another object of the present disclosure is to provide a power conversion device provided with the above converter.
The reactor of the present disclosure can be reduced in weight. Further, the converter and the power conversion device of the present disclosure can be reduced in weight.
First, embodiments of the present disclosure are listed and described.
The reactor can be reduced in weight. The reason for that is that the volume of the second core can be made smaller than that of a comparison core. The comparison core means a core having the same specifications as the second core of the reactor except that the outer side edges of the facing surfaces and those of the tip surfaces are aligned in the Y direction. The tip surfaces are end surfaces in the X direction of the first and second side core parts of the first core. The facing surfaces are surfaces facing the tip surfaces of the first core, out of the surface of the second core. The tip surface of the first core is in contact with at least a partial region of the facing surface of the second core. In the reactor, the width of the facing surface of the second core is shorter than that of the tip surface of the first core. Further, the tip surface of the first core and the facing surface of the second core are in such a positional relationship that the outer side edge of the facing surface is located inwardly of that of the tip surface in the Y direction and the inner side edge of the facing surface and that of the tip surface are substantially aligned in the Y direction. If the tip surface and the facing surface satisfy the above positional relationship, an outer width of the second core is narrower than that of the first core, whereby the volume of the second core can be reduced. Thus, the weight of the second core is reduced, wherefore the magnetic core can be reduced in weight. The width of the tip surface or that of the facing surface is a length of the corresponding surface along the Y direction, and equal to a distance in the Y direction between the outer and inner side edges of the tip surface or facing surface. An outer width of the first core or that of the second core is a maximum length along the Y direction of the first or second core. The outer width of the first core or that of the second core is typically a width, i.e. a length along the Y direction, of the first or second end core part.
The reactor can maintain electromagnetic performance even if the width of the facing surface of the second core is shorter than that of the tip surface of the first core. This is because, in the reactor, the first and second cores have different magnetic properties, specifically, the relative magnetic permeability of the second core is higher than that of the first core. If the width of the facing surface of the second core is shorter than that of the tip surface of the first core, a magnetic path area of the magnetic core is locally reduced in a contact part of the tip surface and the facing surface. Since the respective relative magnetic permeabilities of the second and first cores satisfy the above relationship, a magnetic flux which can pass between the tip surface and the facing surface is easily balanced. In other words, a balance of the magnetic flux can be substantially maintained between the first and second cores. If the first and second cores have the same relative magnetic permeability, but an area of the facing surface is smaller than that of the tip surface, the magnetic flux flowing in the second core becomes smaller than that flowing in the first core near the contact part of the tip surface and the facing surface. If the first and second cores have different relative magnetic permeabilities although the area of the facing surface is smaller than that of the tip surface, an influence on the magnetic flux flowing in the first and second cores is minor if the magnetic flux is in a substantially balanced range. Thus, due to a high relative magnetic permeability of the second core, the width of the facing surface of the second core can be made shorter while the electromagnetic performance such as an inductance is maintained.
In this aspect, a weight reduction is easily realized while the magnetic performance is maintained. The magnetic performance can be maintained since the contact area of the tip surface and the facing surface is easily secured by the width of the facing surface being 60% or more of that of the tip surface. By securing the contact area of the tip surface and the first core, the magnetic flux is easily balanced between the tip surface and the facing surface. That is, since a balance of the magnetic flux can be substantially maintained between the first and second cores, the magnetic performance such as an inductance is easily maintained. The weight reduction can be realized since the width of the facing surface is sufficiently short by being set to 92% or less of the width of the tip surface. Since the width of the facing surface is sufficiently short, the weight of the second core can be effectively reduced.
In this aspect, a predetermined inductance is easily obtained. This is because magnetic properties of the entire magnetic core can be adjusted by the magnetic core including the compact of the composite material having a lower relative magnetic permeability than the powder compact. Further, in this aspect, the magnetic properties of the entire magnetic core can be adjusted even if the magnetic core is not provided with a gap part. Since it is not necessary to provide the magnetic core with the gap part, a leakage magnetic flux from the gap part can be suppressed. Thus, a loss due to the leakage magnetic flux can be reduced. Further, if the first core is constituted by the compact of the composite material and the second core is constituted by the powder compact, the respective relative magnetic permeabilities of the first and second cores easily satisfy the above relationship.
In this aspect, the predetermined inductance is easily obtained.
In this aspect, the predetermined inductance is easily obtained.
In this aspect, the weight reduction is easily realized while the magnetic performance is maintained. This is because the width of the facing surface can be made sufficiently shorter than that of the tip surface by having the relative magnetic permeability ratio of 1.1 or more. Further, if the relative magnetic permeability ratio is 12 or less, the predetermined inductance is easily obtained.
In this aspect, a reduction in the magnetic performance can be efficiently suppressed. This is because a magnetic flux which can pass between the tip surface and the facing surface can be set in a substantially balanced range by the relative magnetic permeability of the first core and the width of the tip surface, and the relative magnetic permeability of the second core and the width of the facing surface satisfying the above relational expression. Since a balance of the magnetic flux can be substantially maintained between the first and second cores, a reduction in the magnetic performance such as an inductance can be suppressed.
In this aspect, the magnetic core of an E-T type or E-I type is typically obtained. In this aspect, the width of the second end core part of the second core is shorter than that of the first end core part of the first core. The width of each end core part is a width in the Y direction of each end core part.
In this aspect, the magnetic core of an E-E type or E-U type is typically obtained. In this aspect, the width of the remaining part of each of the first and second side core parts of the second core is shorter than that of the remaining part of each of the first and second side core parts of the first core. The width of the part of each side core part is a width in the Y direction of each part. The width of the remaining part of each side core part is a width in the Y direction of each remaining part.
The converter can be reduced in weight since including the above reactor.
The power conversion device can be reduced in weight since including the above converter.
Specific embodiments of the present disclosure are described in detail below with reference to the drawings. The same reference signs in figures denote the same components. Note that the present invention is not limited to these illustrations and is represented by claims and intended to include all changes in the scope of claims and in the meaning and scope of equivalents.
[Reactor]
A reactor 1 of a first embodiment is described with reference to
One of features of the reactor 1 of this embodiment is to satisfy the following requirements (a) to (c).
The configuration of the reactor 1 is described in detail below. The coil 2 is shown by a two-dot chain line for the convenience of description in
(Coil)
As shown in
The winding portion 21 of this embodiment has a rectangular tub shape. Rectangular shapes include square shapes. That is, the end surface shape of the winding portion 21 is a rectangular frame shape. The winding portion 21 may have a hollow cylindrical shape. Since the winding portion 21 has a rectangular tube shape, a contact area of the winding portion 21 and an installation target is easily increased as compared to the case where the winding portion 21 has a cylindrical tube shape having the same inner area. The inner area is an opening area of a space surrounded by the inner periphery of the winding portion 21. Since the contact area is increased, heat is easily dissipated to the installation target via the winding portion 21. Moreover, the winding portion 21 is easily disposed on the installation target. Corner parts of the winding portion 21 are rounded.
An end part 21a and an end part 21b of the winding portion 21 are respectively pulled out to an outer peripheral side of the winding portion 21 on one and the other end sides in an axial direction of the winding portion 21. The insulation coating is stripped to expose the conductor in the first and second end parts 21a, 21b of the winding portion 21. Unillustrated terminal members are attached to the end parts 21a, 21b. An external device is connected to the coil 2 via these terminal members. The external device is not shown. A power supply for supplying power to the coil 2 can be cited as the external device.
(Magnetic Core)
As shown in
The magnetic core 3 has a θ shape when viewed from the Z direction as shown in
<Middle Core Part>
The middle core part 30 is a part of the magnetic core 3 to be arranged inside the coil 2. In this embodiment, both end parts in the X direction of the middle core part 30 project from both end surfaces 2a, 2b of the coil 2. These projecting parts are also parts of the middle core part 30.
The shape of the middle core part 30 is not particularly limited as long as corresponding to the inner shape of the winding portion 21. As shown in
The middle core part 30 may be divided or may not be divided in the X direction. The middle core part 30 of this embodiment is divided into two in the X direction and includes a first middle core part 30a and a second middle core part 30b. The first middle core part 30a is located on one side in the X direction of the middle core part 30, specifically, on the side of the first end core part 31. The second middle core part 30b is located on the other side in the X direction of the middle core part 30, specifically, on the side of the second end core part 32. In this embodiment, the first and second middle core parts 30a, 30b are in contact and there is substantially no clearance between the first and second middle core parts 30a, 30b. That is, the middle core part 30 includes no gap part between the first and second middle core parts 30a, 30b. A length of each of the first and second middle core parts 30a, 30b may be appropriately set to obtain desired magnetic properties. The length mentioned here means a length in the X direction. The first middle core part 30a may be longer or shorter than the second middle core part 30b. In this embodiment, the first middle core part 30a is longer than the second middle core part 30b. The first and second middle core parts 30a, 30b have an equal width in the Y direction.
The middle core part 30 may include a gap part. The gap part may be provided between the first and second middle core parts 30a, 30b. The gap part is preferably positioned inside the winding portion 21. By locating the gap part inside the winding portion 21, a leakage magnetic flux from a gap 3g is easily suppressed. Thus, a loss due to the leakage magnetic flux is easily reduced. A length of the gap part may be appropriately set to obtain desired magnetic properties. The length of the gap part is, for example, 0.1 mm or more, further 0.3 mm or more. An upper limit of the length of the gap part is, for example, 2 mm or less, further 1.5 mm or less or 1.0 mm or less. The gap part may be an air gap or a non-magnetic body such as a resin or ceramic may be arranged as such.
<First End Core Part, Second End Core Part>
The first end core part 31 is a part of the magnetic core 3 facing the end surface 2a of the coil 2. The second end core part 32 is a part facing the end surface 2b of the coil 2. Here, facing means that the respective end core parts 31, 32 and the respective end surfaces 2a, 2b of the coil are facing each other. The first and second end core parts 31, 32 are arranged at an interval in the X direction to sandwich the both end surfaces 2a, 2b of the coil 2.
The shapes of the respective first and second end core parts 31, 32 are not particularly limited as long as predetermined magnetic paths are formed. As shown in
<First Side Core Part, Second Side Core Part>
The first and second side core parts 33, 34 are parts of the magnetic core 3 to be arranged outside the coil 2 to sandwich the middle core part 30. That is, the first and second side core parts 33, 34 are arranged at an interval in the Y direction to sandwich both side surfaces along the axial direction of the coil 2. In this embodiment, out of the both side core parts 33, 34, the side core part arranged on one side in the Y direction, i.e. on an upper side, is referred to as the first side core part 33 and the side core part arranged on the other side in the Y direction, i.e. on a lower side, is referred to as the second side core part 34 when viewed from the Z direction as shown in
The first and second side core parts 33, 34 may have lengths to link the first and second end core parts 31, 32. The shapes of the respective side core parts 33, 34 are not particularly limited. As shown in
Widths in the Y direction of the respective first and second side core parts 33, 34 may be equal or different. In this embodiment, the respective widths of the first and second side core parts 33, 34 are equal. Further, the sum of the width of the first side core part 33 and that of the second side core part 34 is equal to the width of the middle core part 30. That is, the sum of a cross-sectional area of the first side core part 33 and that of the second side core part 34 is equal to a cross-sectional area of the middle core part 30.
At least one of the first and second side core parts 33, 34 may be divided or may not be divided in the X direction. Neither of the both side core parts 33, 34 of this embodiment is divided.
If the middle core part 30 includes the aforementioned gap part, the middle core part 30 is shorter than the both side core parts 33, 34. If the sum length of the first and second middle core parts 30a, 30b is shorter than the lengths of the respective side core parts 33, 34, a clearance serving as the gap part can be provided between the first and second middle core parts 30a, 30b.
(First Core, Second Core)
As shown in
<First Core>
The first core 3a may include the first end core part 31, at least a part of the middle core part 30 and at least parts of the both side core parts 33, 34 including the first side core part 33 and the second side core part 34. In this embodiment, as shown in
Each of the first and second side core parts 33, 34 of the first core 3a has the tip surface 3af facing the second core 3b as shown in
<Second Core>
The second core 3b may include the second end core part 32, a remaining part of the middle core part 30 and remaining parts of the first and second side core parts 33, 34. In this embodiment, as shown in
A surface of the second core 3b has the facing surfaces 3bf facing the tip surfaces 3af of the first core 3a in the X direction. That is, the facing surfaces 3bf are regions overlapping the tip surfaces 3af in the X direction, out of the surface of the second core 3b. In this embodiment, the facing surfaces 3bf are provided on the second end core part 32 of the second core 3b. The facing surface 3bf includes a contact region to be brought into contact with the tip surface 3af.
(Positional Relationship of Tip Surface and Facing Surface)
The tip surface 3af and the facing surface 3bf satisfy a specific positional relationship. Specifically, as shown in
(Width Relationship of Facing Surface and Tip Surface)
The width Ws2 of the facing surface 3bf is shorter than the width Ws1 of the tip surface 3af. The width mentioned here means a width in the Y direction. Since the width Ws2 of the facing surface 3bf is shorter than the width Ws1 of the tip surface 3af, the volume of the second core 3b is reduced as compared to the case where width Ws2 of the facing surface 3bf and the width Ws1 of the tip surface 3af are equal. Thus, the weight of the second core 3b is reduced, wherefore the magnetic core 3 can be reduced in weight. In this embodiment, when viewed from the Z direction as shown in
The width Ws2 of the facing surface 3bf is, for example, 60% or more and 92% or less, further 65% or more and 90% or less, or 70% or more and 85% or less of the width Ws1 of the tip surface 3af. Since the width Ws2 of the facing surface 3bf is 60% or more of the width Ws1 of the tip surface 3af, a contact area of the tip surface 3af and the facing surface 3bf is easily secured. By securing the contact area of the tip surface 3af and the facing surface 3bf, a magnetic flux which can pass between the tip surface 3af and the facing surface 3bf is easily set in a substantially balanced range. Within the range in which the magnetic flux is substantially balanced, a balance of the magnetic flux can be substantially maintained between the first and second cores 3a, 3b when magnetic paths are formed in the magnetic core 3. Thus, electromagnetic performance such as an inductance can be maintained. Since the width Ws2 of the facing surface 3bf is 92% or less of the width Ws1 of the tip surface 3af, the width Ws2 of the facing surface 3bf is sufficiently short. Thus, the weight of the second core 3b can be effectively reduced.
(Relative Magnetic Permeability Relationship of First and Second Cores)
The first and second cores 3a, 3b have different relative magnetic permeabilities. Specifically, the relative magnetic permeability of the second core 3b is higher than that of the first core 3a. That is, if μs1 denotes the relative magnetic permeability of the first core 3a and μs2 denotes the relative magnetic permeability of the second core 3b, a relationship of μs1<μs2 is satisfied. Since the relative magnetic permeability of the second core 3b is higher than that of the first core 3a, the magnetic flux is easily balanced between the tip surface 3af and the facing surface 3bf even if the width Ws2 of the facing surface 3bf is shorter than the width Ws1 of the tip surface 3af. Thus, a balance of the magnetic flux can be substantially maintained between the first and second cores 3a, 3b. Therefore, the width Ws2 of the facing surface 3bf can be made shorter than the width Ws1 of the tip surface 3af while the electromagnetic performance such as an inductance is maintained.
The relative magnetic permeability of the first core 3a is, for example, 5 or more and 50 or less. The relative magnetic permeability of the second core 3b is, for example, 50 or more and 500 or less. The relative magnetic permeability of each of the first and second cores 3a, 3b can be appropriately set after satisfying the above relative magnetic permeability relationship. If the respective relative magnetic permeabilities of the first and second cores 3a, 3b are within the respective ranges, a predetermined inductance is easily obtained. The relative magnetic permeability of the first core 3a may be further 10 or more and 45 or less, or 15 or more and 40 or less. The relative magnetic permeability of the second core 3b may be further 100 or more, or 150 or more.
Further, a ratio of the relative magnetic permeability of the second core 3b to that of the first core 3a is preferably 1.1 or more and 12 or less. That is, a relationship of 1.1≤μr2/μr1≤12 is satisfied. If the relative magnetic permeability ratio is 1.1 or more, the relative magnetic permeability of the second core 3b is sufficiently higher than that of the first core 3a. Thus, the width Ws2 of the facing surface 3bf can be made sufficiently shorter than the width Ws1 of the tip surface 3af. If the relative magnetic permeability ratio is 12 or less, a predetermined inductance is easily obtained. The relative magnetic permeability ratio may be further 1.5 or more, 2 or more, or 2.5 or more.
The relative magnetic permeability can be obtained as follows. Ring-shaped measurement samples are cut out respectively from the first and second cores 3a, 3b. Primary winding: 300 turns and secondary winding: 20 turns are applied to each of the measurement samples. A B-H initial magnetization curve is measured in a range of H=0 (Oe) or more and 100 (Oe) or less, and a maximum value of a gradient of this B-H initial magnetization curve is obtained. This maximum value is set as a relative magnetic permeability. The magnetization curve mentioned here is a so-called direct-current magnetization curve.
(Materials)
The first and second cores 3a, 3b are constituted by compacts. Powder compacts, compacts of composite materials and the like can be, for example, cited as the compacts. The first and second cores 3a, 3b are compacts made of mutually different materials. The mutually different materials mean not only a case where materials of individual constituent elements of the respective compacts constituting the first and second cores 3a, 3b are different, but also a case where contents of the respective constituent elements are different even if the materials of the respective constituent elements are the same. For example, even if the first and second cores 3a, 3b are constituted by powder compacts, these cores 3a, 3b are made of mutually different materials if the materials and contents of soft magnetic powders constituting the powder compacts are different. Further, even if the first and second cores 3a, 3b are constituted by compacts of composite materials, these cores 3a, 3b are made of mutually different materials if the materials and contents of soft magnetic powders constituting the composite materials are different.
The powder compact is obtained by compression-forming a raw powder containing a soft magnetic powder. The powder compact has a higher content of the soft magnetic powder as compared to composite materials. Thus, the powder compact easily enhances magnetic properties. A relative magnetic permeability and a saturated magnetic flux density can be cited as the magnetic properties. The powder compact may contain a binder resin, a molding aid and the like. A content of the magnetic powder in the powder compact is, for example, 85% by volume or more and 99.99% by volume or less if the powder compact is 100% by volume.
In the composite material, the soft magnetic powder is dispersed in the resin. The compact of the composite material is obtained by filling a fluid raw material, in which the soft magnetic powder is dispersed in the uncured resin, into a mold and solidifying the resin. The composite material can easily adjust a content of the soft magnetic powder in the resin. Thus, the composite material easily adjusts magnetic properties. A content of the soft magnetic powder in the composite material is, for example, 20% by volume or more and 80% by volume or less if the composite material is 100% by volume.
Particles of soft magnetic metals, coated particles including insulation coatings on the outer peripheries of particles of soft magnetic metals, particles of soft magnetic nonmetals and the like can be cited as particles constituting the soft magnetic powder. Pure iron and iron-based alloys can be cited as the soft magnetic metal. Fe (iron)-Si (silicon) alloys, Fe—Ni (nickel) alloys and the like can be cited as the iron-based alloys. Phosphates and the like can be cited as materials of the insulation coatings. Ferrite and the like can be cited as the soft magnetic nonmetals.
Thermosetting resins and thermoplastic resins can be, for example, cited as the resin of the composite material. An unsaturated polyester resin, an epoxy resin, a urethane resin, a silicone resin and the like can be, for example, cited as the thermosetting resins. A polyphenylene sulfide resin, a polytetrafluoroethylene resin, a liquid crystal polymer, a polyamide resin, a polybutylene terephthalate resin, an acrylonitrile-butadiene-styrene resin and the like can be cited as the thermoplastic resins. Nylon 6, nylon 66, nylon 9T and the like can be cited as the polyimide resin. Besides, a BMC (Bulk Molding Compound) in which calcium carbonate and a glass fiber are mixed in an unsaturated polyester, millable type silicone rubber, millable type urethane rubber and the like can also be used.
The composite material may contain a filler in addition to the soft magnetic powder and the resin. Ceramic fillers such as alumina and silica can be, for example, cited as the filler. By containing the filler in the composite material, heat dissipation can be enhanced. A content of the filler is 0.2% by mass or more and 20% by mass or less, further 0.3% by mass or more and 15% by mass or less, or 0.5% by mass or more and 10% by mass or less when the composite material is 100% by volume.
The content of the soft magnetic powder in the powder compact or the compact of the composite material is regarded as equivalent to an area ratio of the soft magnetic powder in a cross-section of the compact. The content of the soft magnetic powder is obtained as follows. An observation image is obtained by observing the cross-section of the compact by a SEM (Scanning Electron Microscope). A magnification of the SEM is, for example, 200× or more and 500× or less. 10 or more observation images are obtained. A total cross-sectional area is 0.1 cm2 or more. One observation image may be obtained for one cross-section or a plurality of observation images may be obtained for one cross-section. An image processing is applied to each obtained observation image and the contours of the particles are extracted. A binarization processing can be, for example, cited as the image processing. An area ratio of the soft magnetic particles is calculated in each observation image and an average value of the area ratios is obtained. That average value is regarded as the content of the soft magnetic powder.
In this embodiment, the first core 3a is constituted by a compact of a composite material, and the second core 3b is constituted by a powder compact. By constituting the first core 3a by the compact of the composite material and constituting the second core 3b by the powder compact, magnetic properties of the entire magnetic core 3 can be adjusted. Thus, a predetermined inductance is easily obtained even if the magnetic core 3 is not provided with the gap part as in this embodiment. Even if the first and second cores 3a, 3b are made of mutually different materials, the gap part may be provided if necessary. Further, if the first core 3a is constituted by the compact of the composite material and the second core 3b is constituted by the powder compact, the respective relative magnetic permeabilities of the first and second cores 3a, 3b easily satisfy the above relationship. In this embodiment, the relative magnetic permeability of the first core 3a is 20 and that of the second core 3b is 150.
(Relationship of Relative Magnetic Permeability and Tip Surface Width of First Core and Relative Magnetic Permeability and Facing Surface Width of Second Core)
If μs1 denotes the relative magnetic permeability of the first core 3a, Ws1 denotes the width of the tip surface 3af, μs2 denotes the relative magnetic permeability of the second core 3b and Ws2 denotes the width of the facing surface 3bf, {(μr1×Ws1)/(μr2×Ws2)} preferably satisfies a condition of being 0.1 or more and 1.6 or less. If the relative magnetic permeability μs1 and the width Ws1, and the relative magnetic permeability μs2 and the width Ws2 satisfy the above relational expression, a magnetic flux which can pass between the tip surface 3af and the facing surface 3bf can be set in a substantially balanced range. If {(μr1×Ws1)/(μr2×Ws2)} is 0.1 or more and 1.6 or less, a balance of the magnetic flux can be substantially maintained between the first and second cores 3a, 3b since the magnetic flux is in the substantially balanced range. Therefore, a reduction in inductance can be effectively suppressed. {(μr1×Ws1)/(μr2×Ws2)} may be further 0.1 or more and 1.4 or less, or 0.15 or more or 1.2 or less.
(Size)
For example, if the reactor 1 is for vehicle, the size of the magnetic core 3 is as follows as shown in
Further, the sizes of main parts of the magnetic core 3 are as follows. A width of the middle core part 30, i.e. widths of the first and second middle core parts 30a, 30b, is, for example, 10 mm or more and 50 mm or less. Lengths of the first and second end core parts 31, 32 are, for example, 5 mm or more and 40 mm or less. Widths of the first and second side core parts 33, 34 are, for example, 5 mm or more and 40 mm or less. The widths of the first and second side core parts 33, 34 are equivalent to the width Ws1 of the tip surface 3af. The size of each core part is related to a magnitude of a magnetic path area of the magnetic core 3.
(Miscellaneous)
The reactor 1 may include at least one of a case, an adhesive layer, a holding member and a molded resin portion as another component. The case is a member for accommodating an assembly of the coil 2 and the magnetic core 3 inside. The assembly accommodated in the case may be embedded by a sealing resin portion. The adhesive layer fixes the assembly to a placing surface, fixes the assembly to the inner bottom surface of the case and fixes the case to the placing surface or the like. The holding member is interposed between the coil 2 and the magnetic core 3 to ensure electrical insulation between the coil 2 and the magnetic core 3. The molded resin portion integrates the coil 2 and the magnetic core 3 by covering the outer periphery of the assembly.
[Functions and Effects]
The reactor 1 of the first embodiment can be reduced in weight. This is because the width Ws2 of the facing surface 3bf of the second core 3b is shorter than the width Ws1 of the tip surface 3af of the first core 3a. Since the width Ws2 of the facing surface 3b is shorter than the width Ws1 of the tip surface 3af, the width W32 of the second end core part 32 becomes shorter than the width W31 of the first end core part 31 as compared to the case where the width Ws2 of the facing surface 3bf and the width Ws1 of the tip surface 3af are equal. That is, the volume of the second core 3b is reduced. Thus, the weight of the second core 3b is reduced, wherefore the magnetic core 3 can be reduced in weight.
Further, the reactor 1 can maintain the electromagnetic performance such as an inductance. This is because the relative magnetic permeability μs2 of the second core 3b is higher than the relative magnetic permeability μs1 of the first core 3a. Since the relative magnetic permeability μs2 of the second core 3b is higher than the relative magnetic permeability μs1 of the first core 3a, a magnetic flux which can pass between the tip surface 3af and the facing surface 3bf is easily balanced even if the width Ws2 of the facing surface 3b is shorter than the width Ws1 of the tip surface 3af. That is, a balance of the magnetic flux can be substantially maintained between the first and second cores 3a, 3b, and a reduction in inductance can be suppressed. Thus, the width Ws2 of the facing surface 3bf can be made shorter while the inductance is maintained.
Particularly, the reactor 1 easily realizes a weight reduction while maintaining the electromagnetic performance since a ratio of the width Ws2 of the facing surface 3bf to the width Ws1 of the tip surface 3af is in a specific range and a ratio of the relative magnetic permeability μs2 of the second core 3b to the relative magnetic permeability μr1 of the first core 3a is in a specific range. Further, the relative magnetic permeability μr1 and the width Ws1, and the relative magnetic permeability μs2 and the width Ws2 satisfy the specific relationship, whereby a reduction in inductance can be effectively suppressed.
Since the first core 3a is constituted by the compact of the composite material and the second core 3b is constituted by the powder compact, the relative magnetic permeabilities of the first and second cores 3a, 3b are respectively easily set in the predetermined ranges in the reactor 1. Further, if the first core 3a is constituted by the compact of the composite material and the second core 3b is constituted by the powder compact, a predetermined inductance is easily obtained even if the magnetic core 3 is not provided with the gap part.
A reactor 1 of the second embodiment is described with reference to
A first core 3a includes a first end core part 31, an entire middle core part 30 and entire first and second side core parts 33, 34. The middle core part 30 extends in the X direction toward a second end core part 32 from an intermediate part in the Y direction of the first end core part 31. The first core 3a is E-shaped. The first core 3a is a compact of a composite material.
The second core 3b includes only the second end core part 32. The second core 3b does not include the middle core part 30 and the first and second side core parts 33, 34. The second core 3b is I-shaped. The second core 3b is a powder compact.
In this embodiment, an end part of the middle core part 30 on the side of the second end core part 32 is in contact with the second end core part 32. Thus, there is substantially no clearance between the middle core part 30 and the second end core part 32 and a gap part is not present. Unlike this embodiment, a gap part can be provided between the middle core part 30 and the second end core part 32. In the case of providing the gap part between the middle core part 30 and the second end core part 32, the middle core part 30 is shorter than the both side core parts 33, 34. In this way, a clearance serving as the gap part can be provided between the middle core part 30 and the second end core part 32.
A positional relationship of a facing surface 3bf and a tip surface 3af, a relationship of a width Ws2 of the facing surface 3bf and a width Ws1 of the tip surface 3af and a relationship of a relative magnetic permeability μs1 of the first core 3a and a relative magnetic permeability μs2 of the second core 3b are the same as in the first embodiment. As in the first embodiment, the relative magnetic permeability μs1 and the width Ws1, and the relative magnetic permeability μs2 and the width Ws2 satisfy the above relational expression. That is, {(μr1×Ws1)/(μr2×Ws2)} is 0.1 or more and 1.6 or less.
[Functions and Effects]
The reactor 1 of the second embodiment can be reduced in weight while an inductance is maintained similarly to the reactor 1 of the first embodiment.
A reactor 1 of the third embodiment is described with reference to
Each of the first and second side core parts 33, 34 of this embodiment is divided into two in the X direction as shown in
The first parts 33a, 34a and the second parts 33b, 34b are in contact, and there is substantially no clearance between the first parts 33a, 34a and the second parts 33b, 34b. That is, the both side core parts 33, 34 include no gap part between the first parts 33a, 34a and the second parts 33b, 34b. A length of each of the first parts 33a, 34a and the second parts 33b, 34b may be appropriately set to obtain predetermined magnetic properties. The first parts 33a, 34a may be longer or shorter than the second parts 33b, 34b. Further, the respective lengths of the first parts 33a, 34a may be equal or different. The respective lengths of the second parts 33b, 34b may be equal or different. In this embodiment, the first parts 33a, 34a are longer than the second parts 33b, 34b. Further, the respective lengths of the first parts 33a, 34a are equal. The respective lengths of the second parts 33b, 34b are equal.
As shown in
Each of the first parts 33a, 34a in the both side core parts 33, 34 of the first core 3a has the tip surface 3af facing the second core 3b as shown in
A second core 3b includes the second end core part 32, a second middle core part 30b and the second parts 33b, 34b, which are remaining parts of the first and second side core parts 33, 34. The second end core part 32, the second middle core part 30b and the second parts 33b, 34b of the both side core parts 33, 34 are integrally molded. The second parts 33b, 34b extend in the X direction toward the first parts 33a, 34a from both end parts in the Y direction of the second end core part 32. The second core 3b is E-shaped when viewed from the Z direction. The second core 3b is a powder compact.
In this embodiment, the facing surface 3bf is provided on the second part 33b, 34b of each of the first and second side core parts 33, 34. A width Ws2 of the facing surface 3bf of this embodiment is equal to the widths of the second parts 33b, 34b.
The tip surface 3af and the facing surface 3bf satisfy a specific positional relationship as in the first embodiment. Specifically, as shown in
Further, as in the first embodiment, the width Ws2 of the facing surface 3bf is shorter than the width Ws1 of the tip surface 3af. In this embodiment, outer parts in the Y direction of the first parts 33a, 34a project further outward than the second parts 33b, 34b when viewed from the Z direction as shown in
A relationship of a relative magnetic permeability μs1 of the first core 3a and a relative magnetic permeability μs2 of the second core 3b is the same as in the first embodiment. Further, as in the first embodiment, the relative magnetic permeability psi and the width Ws1, and the relative magnetic permeability μs2 and the width Ws2 satisfy the above relational expression. That is, {(μr1×Ws1)/(μr2×Ws2)} is 0.1 or more and 1.6 or less.
[Functions and Effects]
The reactor 1 of the third embodiment can be reduced in weight while an inductance is maintained similarly to the reactor 1 of the first embodiment.
A reactor 1 of the fourth embodiment is described with reference to
A first core 3a includes a first end core part 31, an entire middle core part 30 and first parts 33a, 34a of first and second side core parts 33, 34. The first core 3a is E-shaped. The first core 3a is a compact of a composite material.
A second core 3b includes the first end core part 31, second parts 33b, 34b of the first and second side core parts 33, 34. The second core 3b does not include the middle core part 30. The second core 3b is U-shaped. The second core 3b is a powder compact.
In this embodiment, an end part of the middle core part 30 on the side of the second end core part 32 is in contact with the second end core part 32. Thus, there is substantially no clearance between the middle core part 30 and the second end core part 32 and a gap part is not present. It is also possible to provide a gap part between the middle core part 30 and the second end core part 32 as in the second embodiment.
A positional relationship of a facing surface 3bf and a tip surface 3af, a relationship of a width Ws2 of the facing surface 3bf and a width Ws1 of the tip surface 3af and a relationship of a relative magnetic permeability μs1 of the first core 3a and a relative magnetic permeability μs2 of the second core 3b are the same as in the third embodiment. As in the first embodiment, the relative magnetic permeability μs1 and the width Ws1, and the elative magnetic permeability μs2 and the width Ws2 satisfy the above relational expression. That is, {(μr1×Ws1)/(μr2×Ws2)} is 0.1 or more and 1.6 or less.
[Functions and Effects]
The reactor 1 of the fourth embodiment can be reduced in weight while an inductance is maintained similarly to the reactor 1 of the first embodiment.
[Converter, Power Conversion Device]
The reactors 1 of the first to fourth embodiments can be used in an application satisfying the following energizing conditions. The energizing conditions include, for example, a maximum direct current of about 100 A or more and 1000 A or less, an average voltage of about 100 V or more and 1000 V or less and a use frequency of about 5 kHz or more and 100 kHz or less. The reactor 1 of the first to fourth embodiments can be typically used as a constituent component of a converter to be installed in a vehicle such as an electric or hybrid vehicle and a constituent component of a power conversion device provided with this converter.
A vehicle 1200 such as a hybrid or electric vehicle is, as shown in
The power conversion device 1100 includes a converter 1110 to be connected to the main battery 1210 and an inverter 1120 connected to the converter 1110 for the mutual conversion of a direct current and an alternating current. The converter 1110 shown in this example steps up an input voltage of the main battery 1210 of about 200 V or more and 300 V or less to about 400 V or more and 700 V or less and supplies the stepped-up voltage to the inverter 1120 during the travel of the vehicle 1200. The converter 1110 steps down an input voltage output from the motor 1220 via the inverter 1120 to a direct-current voltage suitable for the main battery 1210 and charges the direct-current voltage to the main battery 1210 during regeneration. The input voltage is a direct-current voltage. The inverter 1120 converts the direct current stepped up by the converter 1110 into a predetermined alternating current and supplies the converted current to the motor 1220 during the travel of the vehicle 1200 and converts an alternating current from the motor 1220 into a direct current and outputs the direct current to the converter 1110 during regeneration.
The converter 1110 includes a plurality of switching elements 1111, a drive circuit 1112 for controlling the operation of the switching elements 1111 and a reactor 1115 as shown in
Besides the converter 1110, the vehicle 1200 is provided with a power supply device converter 1150 connected to the main battery 1210 and an auxiliary power supply converter 1160 connected to a sub-battery 1230 serving as a power source of auxiliary devices and the main battery 1210 and configured to convert a high voltage of the main battery 1210 into a low voltage. The converter 1110 typically performs DC-DC conversion, but the power supply device converter 1150 and the auxiliary power supply converter 1160 perform AC-DC conversion. The power supply device converter 1150 may perform DC-DC conversion. Reactors configured similarly to the reactor 1 of any one of the first to fourth embodiments and appropriately changed in size, shape and the like can be used as reactors of the power supply device converter 1150 and the auxiliary power supply converter 1160. Further, the reactor 1 of any one of the first to fourth embodiments can also be used as a converter for converting input power and only stepping up or only stepping down a voltage.
An influence on electromagnetic performance and a magnetic core weight reduction effect were evaluated for a reactor configured similarly to that of the first embodiment described above. A sample of the reactor used in Test Example 1 includes a magnetic core 3 of an E-T type. A relative magnetic permeability μs1 of a first core 3a is 20. A relative magnetic permeability μr2 of a second core 3b is 150.
In Test Example 1, Sample No. 1-1 in which a width Ws2 of a facing surface 3bf was shorter than a width Ws1 of a tip surface 3af and Sample No. 10 in which a width Ws2 of a facing surface 3bf and a width Ws1 of a tip surface 3af were equal were evaluated. The sizes of the magnetic core 3 and each main part are shown below.
(Size of Magnetic Core)
<Sample No. 10>
<Sample No. 1-1>
In Sample No. 10, the width W32 of the second end core part 32 is 75 mm equal to the width W31 of the first end core part 31. Sample No. 10 is a comparison model. In Sample No. 1-1, the width Ws2 of the facing surface 3bf is shorter than the width Ws1 of the tip surface 3af by 2 mm
(Evaluation of Electromagnetic Performance)
An inductance and a loss were analyzed by computer simulation for the reactor of each sample. JMAG-Designer 19.0 produced by JSOL Corporation, which is a commercially available electromagnetic field analysis software, was used for analysis. For the analysis of the inductance, an inductance when a direct current was caused to flow in a coil was obtained. A current was varied in a range of 0 A to 400 A. Inductances when a current value was 0 A, 100 A, 200 A and 300 A are shown in Table 1. In Table 1, the inductance at each current value in Sample No. 1-1 is shown as a ratio of difference from the inductance at each current value in Sample No. 10. This ratio is shown in percentage with the inductance at each current value in Sample No. 10 set at 100. Further, a graph of inductance obtained by the analysis is shown in
In the analysis of the loss, a total loss was obtained when the reactor was driven under conditions including a direct current of 0 A, an input voltage of 300 V, an output voltage of 600 V and a frequency of 20 kHz. The total loss includes an iron loss of the magnetic core, a loss in the coil and the like. A result of that is shown in Table 1. In Table 1, the total loss of Sample No. 1-1 is shown as a ratio of difference from the total loss of Sample No. 10. This ratio is shown in percentage with the loss of Sample No. 10 set to 100.
(Evaluation of Weight Reduction Effect)
A reduction amount of the volume of the second core in Sample No. 1-1 from the volume of the second core in Sample No. 10 was calculated. A volume reduction amount is obtained by subtracting the volume of the second core of Sample No. 1-1 from that of the second core of Sample No. 10. A result of that is shown in Table 1. Further, a mass ratio of the second core of Sample No. 1-1 to the second core of Sample No. 10 was calculated. The mass ratio shows a ratio of the mass of the second core of Sample No. 1-1 to that of the second core of Sample No. 10 in percentage. The mass ratio is also shown in Table 1.
As shown in Table 1 and
Further, Sample No. 1-1 can reduce the weight of the second core by 4% as compared to Sample No. 10.
In Test Example 2, an influence on electromagnetic performance given by a reduction amount of the width Ws2 of the facing surface 3bf from the width Ws1 of the tip surface 3af was examined while changing the width Ws2. Specifically, evaluations similar to those of Test Example 1 were conducted for reactors of Samples No. 2-1 to No. 2-5 in which the width Ws2 of the facing surface 3bf was made shorter than the width Ws1 of the tip surface 3af in a range of 1 mm to 5 mm Sample No. 2-2 is the same as Sample No. 1-1 of Test Example 1. Samples No. 2-1 to No. 2-5 are different only in the width Ws2 of the facing surface 3bf. A difference (Ws1−Ws2) between the widths Ws1 and Ws2 in each sample and a ratio (Ws2/Ws1) of the width Ws2 to the width Ws1 are respectively shown in Table 2.
An inductance and a total loss were obtained in the same manner as in Test Example 1 for the reactor of each sample. A result of that is shown in Table 2. In Table 2, the inductances at each current value in Samples No. 2-1 to No. 2-5 are shown as ratios of difference from the inductance at each current value in Sample No. 10. The total losses of Samples No. 2-1 to No. 2-5 are shown as ratios of difference from the total loss of Sample No. 10. Further, as in Test Example 1, volume reduction amounts and mass ratios of the second cores in Samples No. 2-1 to No. 2-5 from and to the second core in Sample No. 10 are shown in Table 2.
As shown in Table 2, the volume reduction amount of the second core increases as the width Ws2 of the facing surface 3bf becomes shorter than the width Ws1 of the tip surface 3af, i.e. as the difference (Ws1−Ws2) between the width Ws1 of the tip surface and the width Ws2 of the facing surface becomes larger. That is, the weight reduction effect increases. However, if the width Ws2 of the facing surface becomes even shorter, the deterioration of the inductance characteristic accordingly becomes notable. Specifically, a variation from the inductance at each current value of 0 A to 300 A in Sample No. 10 becomes larger. That is, it becomes difficult to maintain an inductance characteristic equivalent to that of Sample No. 10. As is understood from Table 2, as the width Ws2 of the facing surface is made shorter, the volume reduction amount of the second core increases at a constant rate, whereas an inductance variation range becomes larger than an increasing rate of the volume reduction amount. Since a variation range from the inductance at each current value of 0 A to 300 A in Sample No. 10 is within ±2.5% in Samples No. 2-1 to No. 2-4, it can be said that a predetermined inductance characteristic is substantially maintained. Particularly, since the variation range from the inductance at each current value of 0 A to 300 A in Sample No. 10 is within ±2.0% in Samples No. 2-1 to No. 2-3, the predetermined inductance characteristic can be more satisfactorily maintained. From this, the ratio (Ws2/Ws1) of the width Ws2 of the facing surface to the width Ws1 of the tip surface is thought to be preferably 60% or more, further 70% or more. Further, if not only the weight reduction effect, but also a loss reduction effect is considered, the ratio (Ws2/Ws1) is thought to be preferably 92% or less, further 90% or less.
An influence on electromagnetic performance and a magnetic core weight reduction effect were evaluated for reactors configured similarly to that of the third embodiment described above. Samples of the reactors used in Test Example 3 include a magnetic core 3 of an E-E type. A relative magnetic permeability μs1 of a first core 3a is 20. A relative magnetic permeability μr2 of a second core 3b is 150.
In Test Example 3, Samples No. 3-1 to No. 3-5 in which a width Ws2 of a facing surface 3bf was shorter than a width Ws1 of a tip surface 3af and Sample No. 30 in which a width Ws2 of a facing surface 3bf and a width Ws1 of a tip surface 3af were equal were evaluated. In Samples No. 3-1 to No. 3-5, the width Ws2 of the facing surface 3bf was made shorter than the width Ws1 of the tip surface 3af in a range of 1 mm to 5 mm Samples No. 3-1 to No. 3-5 are different from Sample No. 30 only in the width Ws2 of the facing surface 3bf. The sizes of the magnetic core 3 and each main part are shown below.
(Size of Magnetic Core)
<Sample No. 30>
<Sample No. 3-1>
<Sample No. 3-2>
<Sample No. 3-3>
<Sample No. 3-4>
<Sample No. 3-5>
An inductance was obtained in the same manner as in Test Example 1 for the reactor of each sample. A result of that is shown in Table 3. In Table 3, the inductances at each current value in Samples No. 3-1 to No. 3-5 are shown as ratios of difference from the inductance at each current value in Sample No. 30. Further, volume reduction amounts and mass ratios of the second cores in Samples No. 3-1 to No. 3-5 from and to the second core in Sample No. 30 are shown in Table 3.
As shown in Table 3, even if the magnetic core is of the E-E type, the volume reduction amount of the second core increases as the width Ws2 of the facing surface 3bf becomes shorter than the width Ws1 of the tip surface 3af as in the case of the E-T type of Test Example 2 described above. That is, the weight reduction effect increases. Further, in the sample of the E-E type, as the width Ws2 of the facing surface 3bf becomes shorter, the volume reduction amount becomes larger than that of the sample of the E-T type shown in Table 2 of Test Example 2, but the deterioration of the inductance characteristic becomes more notable. Specifically, a variation from the inductance at each current value of 0 A to 300 A in Sample No. 30 becomes larger. That is, it becomes difficult to maintain the inductance characteristic equivalent to that of Sample No. 30. Since a variation range from the inductance at each current value of 0 A to 300 A in Sample No. 30 is within ±2.5% in Samples No. 3-1 to No. 3-3, it can be said that a predetermined inductance characteristic is substantially maintained. Particularly, since the variation range from the inductance in Sample No. 30 is within ±2.0% in Samples No. 3-1 and No. 3-2, the predetermined inductance characteristic can be more satisfactorily maintained. From this, the ratio (Ws2/Ws1) of the width Ws2 of the facing surface to the width Ws1 of the tip surface is thought to be preferably 70% or more, further 80% or more in the magnetic core of the E-E type. Further, if the weight reduction effect is considered, the ratio (Ws2/Ws1) is thought to be preferably 92% or less, further 90% or less.
Further, total losses were obtained in the same manner as in Test Example 1 for the reactors of Samples No. 3-1 to No. 3-5. The loss of each sample was comparable to the loss of Sample No. 30.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-141155 | Aug 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/028621 | 8/2/2021 | WO |
