Reactor, converter, and power conversion device

Abstract

A reactor is provided with a coil and a magnetic core, the magnetic core is provided with a first core and a second core, the first core comprises a first end core part and a side core part, the second core comprises a second end core part, at least one of the first core and the second core comprises at least a part of an intermediate core part, the intermediate core part is arranged in the coil, and the side core part is arranged in the coil. The side core portion is arranged in parallel with the middle core portion across the coil, the relative permeability of the first core is lower than the relative permeability of the second core, the side core portion is provided with a first end combined with the first end core portion and a second end combined with the second end core portion, and the distance between the side core portion and the coil is larger than the distance between the side core portion and the coil. The second interval of the second end is larger than the first interval of the first end, and the ratio of the first interval to the second interval is 0.32 or more and 0.70 or less.

Description

Technical Field

[0001] The present invention relates to a reactor, a converter, and a power conversion device. This application claims priority based on Japanese Patent Application No. 2022-208307 filed on December 26, 2022, and incorporates by reference all the descriptions recited in the said Japanese application. Background Art

[0002] Among the components of a converter mounted on a vehicle such as a hybrid vehicle, there is a reactor. The reactor includes a coil and a magnetic core. The reactor described in Patent Document 1 Figure 5 to FIG. 8 includes a magnetic core formed by combining one coil and two magnetic chip pieces. The magnetic core is a so-called E-E core type formed by two E-shaped magnetic chip pieces. The magnetic core is formed in a θ shape by combining the end faces of the two magnetic chip pieces facing each other. The magnetic core has an end core portion, an intermediate core portion, and a side core portion. The end core portion is arranged to face the end face of the coil. The intermediate core portion is arranged inside the coil. The side core portion is arranged in parallel with the intermediate core portion with the coil therebetween. Prior Art Documents Patent Documents

[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-201509 Summary of the Invention

[0004] The reactor of the present invention includes a coil and a magnetic core, the coil has a cylindrical shape, and the magnetic core has a θ shape, the coil has a first end face and a second end face, the magnetic core includes a first core and a second core, the first core includes a first end core portion and a side core portion, the second core includes a second end core portion, at least one of the first core and the second core includes at least a part of the intermediate core portion, the first end core portion is arranged to face the first end face of the coil, the second end core portion is arranged to face the second end face of the coil, the intermediate core portion is arranged inside the coil, the side core portion has a first side core portion and a second side core portion arranged in parallel with the intermediate core portion with the coil therebetween, the relative magnetic permeability of the first core is lower than that of the second core, the first side core portion and the second side core portion respectively have a first end combined with the first end core portion and a second end combined with the second end core portion, Regarding the intervals between the first side core portion and the coil and between the second side core portion and the coil, the second interval at the second end is greater than the first interval at the first end, The ratio of the first interval to the second interval is 0.32 or more and 0.70 or less. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 It is a schematic perspective view showing the reactor of Embodiment 1. Figure 2 It is a schematic top view showing the reactor of Embodiment 1. Figure 3 It shows Figure 2 A schematic top view of half of the shown reactor. Figure 4 It is a schematic top view showing the reactor of Embodiment 2. Figure 5 It shows Figure 4 A schematic top view of half of the shown reactor. Figure 6 It is a schematic diagram showing the configuration of the power supply system of a hybrid vehicle. Figure 7 It is a circuit diagram schematically showing a power conversion device including a converter. DETAILED DESCRIPTION OF THE INVENTION

[0006] [Problems to be Solved by the Invention] It is desired to reduce the coil loss caused by the leakage magnetic flux from the magnetic core.

[0007] One object of the present invention is to provide a reactor capable of reducing coil loss.

[0008] [Effects of the Invention] The reactor of the present invention can reduce coil loss.

[0009] [Description of Embodiments of the Invention] First, embodiments of the present invention will be listed and described.

[0010] (1) The reactor of the present invention includes a coil and a magnetic core, The coil has a cylindrical shape, and the magnetic core has a θ shape, The coil has a first end face and a second end face, The magnetic core includes a first core and a second core, The first core includes a first end core portion and a side core portion, The second core includes a second end core portion, At least one of the first core and the second core includes at least a part of the intermediate core portion, The first end core portion is arranged to face the first end surface of the coil, The second end core portion is arranged to face the second end surface of the coil. The intermediate core is arranged in the coil, The side core portion includes a first side core portion and a second side core portion arranged in parallel with the middle core portion with the coil interposed therebetween. The relative magnetic permeability of the first core is lower than the relative magnetic permeability of the second core, The first side core portion and the second side core portion respectively have a first end coupled to the first end core portion and a second end coupled to the second end core portion. Regarding the interval between the first side core and the coil and the interval between the second side core and the coil, the second interval at the second end is larger than the first interval at the first end. A ratio of the first interval to the second interval is greater than or equal to 0.32 and less than or equal to 0.70.

[0011] The reactor of the present invention can reduce coil loss. When the relative magnetic permeability of the side core is low and the relative magnetic permeability of the second end core is high, leakage flux that takes a shortcut from the side core to the second end core may be generated in the vicinity of the second end. The leakage flux is linked with the coil, so that the coil generates loss. According to the reactor of the present invention, the second interval at the second end is larger than the first interval at the first end, so that the leakage flux linked with the coil can be suppressed. Since the leakage flux to the coil is reduced, the coil loss can be reduced. By making the ratio of the first interval to the second interval less than 0.70, the leakage flux to the coil can be fully suppressed, so the coil loss can be effectively reduced. In particular, when the ratio of the first interval to the second interval is greater than 0.32 and less than 0.70, the reduction in inductance can be suppressed and the coil loss can be effectively reduced.

[0012] The first core and the second core have different magnetic properties, so that the magnetic properties of the entire magnetic core can be adjusted. The first core has a lower relative magnetic permeability than the second core, so that a predetermined inductance can be easily obtained.

[0013] (2) In the reactor described in (1) above, it is also possible that: The intermediate core has a first intermediate core and a second intermediate core, The first intermediate core portion is combined with the first end core portion, The second intermediate core portion is combined with the second end core portion.

[0014] The structure of (2) above can make the magnetic properties of the first intermediate core portion and the second intermediate core portion different. With this structure, the magnetic properties of the entire magnetic core can be adjusted.

[0015] (3) In the reactor described in (2) above, it may also be that The middle core portion has a gap portion between the first middle core portion and the second middle core portion.

[0016] The structure of (3) above can adjust the magnetic characteristics of the entire magnetic core through the gap portion.

[0017] (4) In the reactor described in any one of (1) to (3) above, it may also be that The first side core portion and the second side core portion each have a tapered shape with a width that tapers from the first end toward the second end.

[0018] The structure of (4) above is liable to reduce coil loss.

[0019] (5) In the reactor described in any one of (1) to (3) above, it may also be that The first side core portion and the second side core portion each have a stepped shape with a width that tapers from the first end toward the second end.

[0020] The structure of (5) above is liable to reduce coil loss.

[0021] (6) In the reactor described in any one of (1) to (5) above, it may also be that The relative magnetic permeability of the first core is 5 or more and 50 or less.

[0022] The structure of (6) above is liable to obtain a predetermined inductance.

[0023] (7) In the reactor described in any one of (1) to (6) above, it may also be that The first core is composed of a formed body of a composite material in which soft magnetic powder is dispersed in resin.

[0024] Generally, the relative magnetic permeability of a formed body of a composite material is low. The structure of (7) above is liable to form a magnetic core in which the relative magnetic permeability of the first core is lower than that of the second core. By forming the first core of a formed body of a composite material, it is easy to adjust the relative magnetic permeability of the first core to, for example, 5 or more and 50 or less.

[0025] (8) In the reactor described in any one of (1) to (7) above, it may also be that The relative magnetic permeability of the second core is 100 or more and 500 or less.

[0026] The structure of (8) above is liable to obtain a predetermined inductance.

[0027] (9)In the reactor described in any one of the above (1) to (8), it is also possible that the second core is composed of a powder-compacted body.

[0028] Generally, the relative magnetic permeability of the powder-compacted body is high. The structure of the above (9) easily forms a magnetic core in which the relative magnetic permeability of the first core is lower than that of the second core. By forming the second core of a powder-compacted body, it is easy to adjust the relative magnetic permeability of the second core to, for example, 100 or more and 500 or less.

[0029] (10) The converter of the present invention includes the reactor described in any one of the above (1) to (9).

[0030] The converter of the present invention has small losses because it includes the reactor of the present invention.

[0031] (11) The power conversion device of the present invention includes the converter described in the above (10).

[0032] The power conversion device of the present invention has small losses because it includes the converter of the present invention.

[0033] [Details of Embodiments of the Present Invention] The following describes specific examples of embodiments of the present invention with reference to the drawings. The same reference numerals in the drawings denote the same objects. In addition, the present invention is not limited to these examples, but is shown by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0034] [Embodiment 1] [Reactor] Refer to Figures 1 to 3 to describe the reactor 1a of Embodiment 1. The reactor 1a includes a coil 2 and a magnetic core 3. The magnetic core 3 includes a first core 3a and a second core 3b. As Figure 2 shown, the magnetic core 3 is formed by combining the first core 3a and the second core 3b. The magnetic core 3 is formed in a θ shape by an intermediate core portion 31, side core portions 33, and end core portions 35. Figure 1 is a perspective view of the reactor 1a viewed from above. Figure 2 is a top view of the reactor 1a viewed from above. Figure 3 is only showing Figure 2 a partial top view of half of the reactor 1a shown in

[0035] The reactor 1a of Embodiment 1 is characterized in that it satisfies the following aspects of requirements (a) and (b). (a) The relative magnetic permeability of the first core 3a is lower than that of the second core 3b (b) As Figure 3As shown, the second interval D2 is greater than the first interval D1, and the ratio D1 / D2 of the first interval D1 to the second interval D2 is 0.32 or more and 0.70 or less.

[0036] Since the second interval D2 of the reactor 1a is greater than the first interval D1, the loss of the coil 2 can be reduced. In particular, since the ratio D1 / D2 of the first interval D1 to the second interval D2 is 0.32 or more and 0.70 or less, the reduction of the inductance can be suppressed and the loss of the coil 2 can be effectively reduced. Hereinafter, the structure of the reactor 1a will be described in detail.

[0037] <Coil> As Figure 1 and Figure 2 shown, the coil 2 is disposed in the intermediate core portion 31 of the magnetic core 3. The coil 2 has a cylindrical shape. The coil 2 has a first end face 2a and a second end face 2b. In the present embodiment, the coil 2 is a flat-standing coil formed by flat-standing winding of a flat wire.

[0038] The shape of the coil 2 may be a polygonal cylindrical shape or a cylindrical shape. The polygonal cylindrical shape means that the contour shape of the end face of the coil 2 is a polygon. The polygon is, for example, a quadrilateral, a hexagon, or an octagon. The quadrilateral includes a rectangle. The rectangle includes a square. The quadrilateral is not limited to a geometric quadrilateral, but includes a shape formed by connecting four corner portions. That is, it also includes a shape in which the four corner portions are rounded by chamfering, or a shape in which the four corner portions are chamfered into a straight shape, etc., in which a slight change is applied to the fine portion. The cylindrical shape means that the contour shape of the end face of the coil 2 is a circle. The circle includes not only a perfect circle shape but also an elliptical shape. In the present embodiment, the shape of the coil 2 is a rectangular cylindrical shape.

[0039] <Magnetic Core> As Figure 1 and Figure 2 shown, the magnetic core 3 has an intermediate core portion 31, side core portions 33, and end core portions 35. In Figure 2 and Figure 3 , the boundaries between the intermediate core portion 31 and the end core portions 35 and the boundaries between the side core portions 33 and the end core portions 35 are indicated by double-dashed lines. The same applies to the following Figure 4 and Figure 5 . As Figure 2 shown, the magnetic core 3 has a θ shape when viewed from above.

[0040] In the following description, the X-axis direction, Y-axis direction, and Z-axis direction are defined as follows. The X-axis direction is the direction along the axis of the coil 2, and is the direction from the first end face 2a toward the second end face 2b. The Y-axis direction is the direction in which the intermediate core portion 31 and the side core portions 33 are arranged side by side, and is the direction from the intermediate core portion 31 toward the side core portions 33. The Y-axis direction is orthogonal to the X-axis direction. The direction from the intermediate core portion 31 toward the first side core portion 331 is defined as the Y1 direction. The direction from the intermediate core portion 31 toward the second side core portion 332 is defined as the Y2 direction. The Z-axis direction is orthogonal to both the X-axis direction and the Y-axis direction. When the XY plane including the X-axis and the Y-axis is set to be horizontal, the Z-axis direction is the direction from bottom to top.

[0041] The magnetic core 3 forms a θ-shaped closed magnetic circuit. When the coil 2 is energized, magnetic flux flows through the magnetic core 3. The magnetic flux generated by the coil 2 flows in such a way as to return from the intermediate core portion 31 via the end core portions 35 and the side core portions 33 to the intermediate core portion 31. Figure 2 The dashed arrows in [Figure] indicate the flow of magnetic flux. The same applies to the [Figure] described later. Figure 4 The same also applies in the following.

[0042] (Intermediate core portion) As Figure 2 shown, the intermediate core portion 31 is disposed inside the coil 2. The number of the intermediate core portions 31 is one. The intermediate core portion 31 extends in the X-axis direction. The direction along the length of the intermediate core portion 31 coincides with the direction along the axis of the coil 2. The length of the intermediate core portion 31 is the same as or greater than the length of the coil 2. The length referred to here means the distance along the X-axis direction. The both end portions of the intermediate core portion 31 may protrude from the both end faces of the coil 2. The protruding portions are also part of the intermediate core portion 31. The shape of the intermediate core portion 31 is a shape corresponding to the inner shape of the coil 2. In the present embodiment, the shape of the intermediate core portion 31 is substantially rectangular parallelepiped.

[0043] The intermediate core portion 31 is disposed between the first end core portion 35a and the second end core portion 35b. The first end core portion 35a and the second end core portion 35b will be described later. The intermediate core portion 31 has a first end 32a and a second end 32b. The first end 32a is joined to the first end core portion 35a. The second end 32b is joined to the second end core portion 35b.

[0044] In the present embodiment, the intermediate core portion 31 has a first intermediate core portion 31a and a second intermediate core portion 31b. The first intermediate core portion 31a and the second intermediate core portion 31b are arranged in series along the X-axis direction. The boundary between the first intermediate core portion 31a and the second intermediate core portion 31b is located within the coil 2. The first intermediate core portion 31a includes a first end 32a that is joined to the first end core portion 35a. The second intermediate core portion 31b includes a second end 32b that is joined to the second end core portion 35b. By "joined" it means being adhered together without separation. The first intermediate core portion 31a and the first end core portion 35a may also be integrally formed. In the case where the first intermediate core portion 31a and the first end core portion 35a are respectively independent separate components, for example, the first end 32a may be bonded to the first end core portion 35a, and they may also be integrated by at least a part of the first intermediate core portion 31a and the first end core portion 35a being covered by a resin molded part. The second intermediate core portion 31b and the second end core portion 35b may also be integrally formed. In the case where the second intermediate core portion 31b and the second end core portion 35b are respectively independent separate components, for example, the second end 32b may be bonded to the second end core portion 35b, and they may also be integrated by at least a part of the second intermediate core portion 31b and the second end core portion 35b being covered by a resin molded part. The resin molded part is a formed member that is successively formed in such a way as to cover at least a part of each of the first core 3a and the second core 3b. In the present embodiment, the first intermediate core portion 31a and the first end core portion 35a are integrally formed. The second intermediate core portion 31b and the second end core portion 35b are integrally formed.

[0045] The lengths of the first intermediate core portion 31a and the second intermediate core portion 31b can be appropriately set. In the present embodiment, the length of the first intermediate core portion 31a is different from the length of the second intermediate core portion 31b. The first intermediate core portion 31a is longer than the second intermediate core portion 31b. The first intermediate core portion 31a may also be shorter than the second intermediate core portion 31b. The lengths of the first intermediate core portion 31a and the second intermediate core portion 31b may also be the same.

[0046] In the present embodiment, the intermediate core portion 31 has a gap portion 31g. The gap portion 31g is provided between the first intermediate core portion 31a and the second intermediate core portion 31b. By having the gap portion 31g in the intermediate core portion 31, the inductance can be adjusted. The gap portion 31g is located within the coil 2. When the gap portion 31g is located within the coil 2, compared with the case where the gap portion 31g is exposed from the coil 2, the leakage magnetic flux from the gap portion 31g is reduced. Therefore, it is easy to suppress the linking of the leakage magnetic flux from the gap portion 31g with the coil 2. The loss caused by the leakage magnetic flux from the gap portion 31g can be reduced. The length of the gap portion 31g is appropriately set to obtain a predetermined inductance. The length of the gap portion 31g is, for example, 0.1 mm or more and 3 mm or less, 0.3 mm or more and 2.5 mm or less, and further 0.5 mm or more and 2 mm or less. The gap portion 31g may be an air gap. The gap portion 31g may be made of a non-magnetic material, and the non-magnetic material is made of resin or ceramic. When the intermediate core portion 31 has the gap portion 31g, the length of the intermediate core portion 31 is the total length of the length of the first intermediate core portion 31a, the length of the second intermediate core portion 31b, and the length of the gap portion 31g. There may be no gap portion 31g. When there is no gap portion 31g, the first intermediate core portion 31a and the second intermediate core portion 31b are in contact with each other, and there is substantially no gap between the first intermediate core portion 31a and the second intermediate core portion 31b.

[0047] (End core portion) As Figure 2 shown, the end core portions 35 are arranged outside the coil 2. The end core portions 35 are arranged so as to face the two end faces of the coil 2 respectively. The number of the end core portions 35 is two. The end core portions 35 have a first end core portion 35a and a second end core portion 35b. The first end core portion 35a and the second end core portion 35b are arranged at intervals in the X-axis direction. The first end core portion 35a and the second end core portion 35b each have an inner side face facing each other. The first end core portion 35a faces the first end face 2a of the coil 2. The first end 32a of the intermediate core portion 31 is coupled to the first end core portion 35a. The second end core portion 35b faces the second end face 2b of the coil 2. The second end 32b of the intermediate core portion 31 is coupled to the second end core portion 35b.

[0048] The shapes of the first end core portion 35a and the second end core portion 35b are not particularly limited as long as they are shapes that form a predetermined magnetic path. In the present embodiment, the shapes of the first end core portion 35a and the second end core portion 35b are each substantially rectangular parallelepiped-shaped.

[0049] (Side core portion) As Figure 2As shown, the side core portion 33 is disposed outside the coil 2. The side core portion 33 is arranged in parallel with the intermediate core portion 31 with the coil 2 therebetween. The number of side core portions 33 is two. The side core portions 33 extend in the X-axis direction. The direction along the length of the side core portion 33 is parallel to the direction along the length of the intermediate core portion 31. The length of the side core portion 33 is equal to the length of the intermediate core portion 31.

[0050] The side core portion 33 has a first side core portion 331 and a second side core portion 332. The first side core portion 331 and the second side core portion 332 are arranged at intervals in the Y-axis direction. The first side core portion 331 is arranged to be away from the intermediate core portion 31 in the Y1 direction. The second side core portion 332 is arranged to be away from the intermediate core portion 31 in the Y2 direction. In the present embodiment, the first side core portion 331 and the second side core portion 332 are arranged symmetrically with respect to the center line of the intermediate core portion 31.

[0051] The first side core portion 331 and the second side core portion 332 are disposed between the first end core portion 35a and the second end core portion 35b. The first side core portion 331 and the second side core portion 332 each have a first end 34a and a second end 34b. The first end 34a is joined to the first end core portion 35a. The second end 34b is joined to the second end core portion 35b.

[0052] In the present embodiment, the side core portion 33 and the first end core portion 35a are integrally formed. The side core portion 33 and the first end core portion 35a may also be separate independent components. In this case, for example, the first end 34a may be bonded to the first end core portion 35a, and they may also be integrated by at least a part of the side core portion 33 and the first end core portion 35a being covered by a resin molding. In the present embodiment, the side core portion 33 and the second end core portion 35b are separate independent components. The side core portion 33 and the second end core portion 35b are integrated by a resin molding (not shown). The second end 34b of the side core portion 33 may also be bonded to the second end core portion 35b.

[0053] <The interval between the side core and the coil> In the present embodiment, the interval between the first side core portion 331 and the coil 2 and the interval between the second side core portion 332 and the coil 2 are not constant in the X-axis direction respectively. That is, the interval between the side core portion 33 and the coil 2 is not constant over the entire length of the side core portion 33. The interval between the side core portion 33 and the coil 2 becomes larger from the first end 34a toward the second end 34b. The interval between the side core portion 33 and the coil 2 refers to the interval between the inner side surface of the side core portion 33 and the outer peripheral surface of the coil 2. The inner side surface of the side core portion 33 is the surface facing the outer peripheral surface of the coil 2.

[0054] Refer to Figure 3 , and the interval between the side core portion 33 and the coil 2 will be described in detail. Figure 3 Only showing Figure 2Half of the portion of the intermediate core 31 of the reactor 1a shown that is bisected by the center line, including the first side core 331. Here, refer to Figure 3 The interval between the first side core 331 and the coil 2 will be described, but the interval between the second side core 332 and the coil 2 is the same. Regarding the interval between the first side core 331 and the coil 2, the second interval D2 at the second end 34b is greater than the first interval D1 at the first end 34a. The first interval D1 refers to the interval between the inner surface of the first side core 331 at the first end 34a and the imaginary plane that extends the outer peripheral surface of the coil 2. When the corners of the end face and the inner surface at the first end 34a are chamfered, it is regarded as not being chamfered. That is, the interval between the corner of the extended plane of the end face and the extended plane of the inner surface at the first end 34a and the above-mentioned imaginary plane is regarded as the first interval D1. The second interval D2 refers to the interval between the inner surface of the first side core 331 at the second end 34b and the imaginary plane that extends the outer peripheral surface of the coil 2. When the corners of the end face and the inner surface at the second end 34b are chamfered, it is regarded as not being chamfered. That is, the interval between the corner of the extended plane of the end face and the extended plane of the inner surface at the second end 34b and the above-mentioned imaginary plane is regarded as the second interval D2.

[0055] The ratio of the first interval D1 to the second interval D2 is 0.32 or more and 0.70 or less. The ratio of the first interval D1 to the second interval D2 is expressed as D1 / D2. The smaller the ratio D1 / D2, the larger the second interval D2. The larger the second interval D2, the larger the interval between the side core 33 and the coil 2 in the vicinity of the second end 34b. Therefore, it is possible to suppress the leakage flux that takes a shortcut from the side core 33 toward the second end core 35b from linking with the coil 2 in the vicinity of the second end 34b. The leakage flux to the coil 2 is reduced, so the loss of the coil 2 can be reduced. By the ratio D1 / D2 being 0.70 or less, the leakage flux to the coil 2 can be sufficiently suppressed, so the loss of the coil 2 can be effectively reduced. When the ratio D1 / D2 becomes too small, that is, when the second interval D2 becomes too large, the inductance may decrease, and it may be difficult to obtain the predetermined inductance. By the ratio D1 / D2 being 0.32 or more, it is easy to suppress the decrease in inductance. The ratio D1 / D2 can also be 0.35 or more and 0.70 or less, 0.40 or more and 0.60 or less.

[0056] <Shape of the side core> The side core portion 33 has a shape in which the width of the side core portion 33 tapers from the first end 34a toward the second end 34b. The side core portion 33 only needs to have the width of the second end 34b thinner than the width of the first end 34a. The side core portion 33 only needs to have a portion with a tapered width at least in part between the first end 34a and the second end 34b, and may also have a portion with a constant width between the first end 34a and the second end 34b. The width of the side core portion 33 is the dimension of the side core portion 33 in the Y-axis direction. In the present embodiment, the shapes of the first side core portion 331 and the second side core portion 332 are line-symmetric with respect to the center line of the intermediate core portion 31.

[0057] Refer to Figure 3 , and the shape of the side core portion 33 in the present embodiment will be described in detail. Here, the shape of the first side core portion 331 will be described. The first side core portion 331 has a tapered shape. The so-called tapered shape means a shape having a portion where the width continuously tapers from the first end 34a toward the second end 34b. In the present embodiment, the first side core portion 331 is formed in a tapered shape over its entire length. The inner surface of the first side core portion 331 has an inclined surface 33t that is inclined with respect to the outer peripheral surface of the coil 2. The inclined surface 33t is inclined so as to be away from the outer peripheral surface of the coil 2 from the first end 34a toward the second end 34b. The angle of the inclined surface 33t with respect to the outer peripheral surface of the coil 2 is appropriately set so that the ratio of the first interval D1 to the second interval D2 satisfies a predetermined range. The so-called angle of the inclined surface 33t means the angle formed by the inclined surface 33t and the outer peripheral surface of the coil 2. The outer peripheral surface of the coil 2 is parallel to the X-axis. The angle of the inclined surface 33t can be appropriately set according to the length of the first side core portion 331. The angle of the inclined surface 33t is, for example, 1° or more and less than 5°, and further 2° or more and 4° or less.

[0058] (First core · Second core) As Figure 2 shown, the magnetic core 3 is composed of a first core 3a and a second core 3b. In the present embodiment, the first core 3a has an E-shaped configuration, and the second core 3b has a T-shaped configuration. That is, the magnetic core 3 is an E-T type composed of the E-shaped first core 3a and the T-shaped second core 3b.

[0059] (First core) The first core 3a includes a first end core portion 35a and a side core portion 33. In the present embodiment, the first core 3a has a first end core portion 35a, a first intermediate core portion 31a, a first side core portion 331, and a second side core portion 332. The first intermediate core portion 31a, the first end core portion 35a, the first side core portion 331, and the second side core portion 332 are integrally formed. Since the first core 3a is an integrally formed product, the core portions constituting the first core 3a are of the same material. That is, the magnetic characteristics of the core portions constituting the first core 3a are substantially the same. The shape of the first core 3a is E-shaped when viewed from above.

[0060] (Second core) The second core 3b includes a second end core portion 35b. In the present embodiment, the second core 3b has a second end core portion 35b and a second intermediate core portion 31b. The second end core portion 35b and the second intermediate core portion 31b are integrally formed. Since the second core 3b is an integrally formed product, each core portion constituting the second core 3b is of the same material. That is, the magnetic characteristics of each core portion constituting the second core 3b are substantially the same. The shape of the second core 3b is T-shaped in a top view.

[0061] At least one of the first core 3a and the second core 3b includes at least a part of the intermediate core portion 31. The first core 3a may also have the entire intermediate core portion 31. When the first core 3a has the entire intermediate core portion 31, the second core 3b only has the second end core portion 35b. In this case, the shape of the second core 3b is I-shaped in a top view. The second core 3b may also have the entire intermediate core portion 31. When the second core 3b has the entire intermediate core portion 31, the first core 3a is composed of a first end core portion 35a, a first side core portion 331, and a second side core portion 332. In this case, the shape of the first core 3a is U-shaped in a top view.

[0062] <First core · Second relative permeability> The relative permeability of the first core 3a is lower than the relative permeability of the second core 3b. That is, in the magnetic core 3, the relative permeability of the side core portion 33 is lower than the relative permeability of the second end core portion 35b. The relative permeabilities of the first core 3a and the second core 3b are appropriately set on the basis of satisfying the above relationship to obtain a predetermined inductance. The relative permeability of the first core 3a is, for example, 5 or more and 50 or less. The relative permeability of the second core 3b is, for example, 50 or more and 500 or less. If the relative permeability of the first core 3a is in the range of 5 or more and 50 or less, and the relative permeability of the second core 3b is in the range of 50 or more and 500 or less, it is easy to obtain a predetermined inductance. The relative permeability of the first core 3a may also be 10 or more and 45 or less, and further 15 or more and 40 or less. The relative permeability of the second core 3b may also be 100 or more and 450 or less, and further 150 or more and 400 or less. The difference between the relative permeability of the first core 3a and the relative permeability of the second core 3b is, for example, 50 or more. The difference between the relative permeability of the first core 3a and the relative permeability of the second core 3b may also be 50 or more and 450 or less, and further 100 or more and 400 or less.

[0063] The relative magnetic permeability can be obtained as follows. Annular measurement specimens are cut out from the first core 3a and the second core 3b respectively. Windings are applied to each measurement specimen with 300 turns on the primary side and 20 turns on the secondary side. The B-H initial magnetization curve is measured in the range from H = 0 (Oe) to 100 (Oe), and the maximum value of B / H of the B-H initial magnetization curve is obtained. This maximum value is taken as the relative magnetic permeability. The magnetization curve mentioned here is the so-called DC magnetization curve.

[0064] <Material of the first core and the second core> The first core 3a and the second core 3b are each composed of a formed body of a soft magnetic material. The formed body is, for example, a compacted powder formed body or a formed body of a composite material. The first core 3a and the second core 3b are composed of formed bodies of mutually different materials. By mutually different materials, it goes without saying that in each formed body constituting the first core 3a and the second core 3b, the materials of the respective constituent elements are different, and it also includes the case where even if the materials of the respective constituent elements are the same, the contents constituting the constituent elements are different. For example, even if the first core 3a and the second core 3b are composed of compacted powder formed bodies, if at least one of the material and content of the soft magnetic powder constituting the compacted powder formed body is different, they are also materials of mutually different types. In addition, even if the first core 3a and the second core 3b are composed of formed bodies of composite materials, if at least one of the material and content of the soft magnetic powder constituting the composite material is different, they are also materials of mutually different types.

[0065] The compacted powder formed body is formed by compression molding of raw powder containing soft magnetic powder. Compared with the formed body of the composite material, the content of the soft magnetic powder is large. Therefore, compared with the formed body of the composite material, the magnetic properties are high. The magnetic properties are, for example, relative magnetic permeability and saturation magnetic flux density. The compacted powder formed body may also contain at least one of an adhesive resin and a forming aid. When the compacted powder formed body is set to 100% by volume, the content of the soft magnetic powder in the compacted powder formed body is, for example, 85% by volume or more and 99.99% by volume or less.

[0066] The formed body of the composite material is formed by dispersing soft magnetic powder in resin. The formed body of the composite material is obtained by filling a fluid raw material in which soft magnetic powder is dispersed in uncured resin into a mold and curing the resin. The formed body of the composite material can easily adjust the content of the soft magnetic powder. Therefore, the magnetic properties of the formed body of the composite material can be easily adjusted. When the formed body of the composite material is set to 100% by volume, the content of the soft magnetic powder in the formed body of the composite material is, for example, 20% by volume or more and 80% by volume or less.

[0067] The particles constituting the soft magnetic powder are at least one selected from the group consisting of soft magnetic metal particles, coated particles having an insulating coating portion on the outer periphery of the soft magnetic metal particles, and soft magnetic non-metal particles. The soft magnetic metal is, for example, pure iron or an iron-based alloy. The iron-based alloy is, for example, an Fe (iron)-Si (silicon) alloy or an Fe-Ni (nickel) alloy. The insulating coating portion is, for example, phosphate. The soft magnetic non-metal is, for example, ferrite.

[0068] In the present embodiment, the first core 3a is formed of a formed body of a composite material. The second core 3b is formed of a compacted powder formed body. By forming the first core 3a of a formed body of a composite material and the second core 3b of a compacted powder formed body, the magnetic characteristics of the entire magnetic core 3 can be adjusted. In addition, when the first core 3a is formed of a formed body of a composite material, the relative magnetic permeability of the first core 3a easily satisfies 5 or more and 50 or less. When the second core 3b is formed of a compacted powder formed body, the relative magnetic permeability of the second core 3b easily satisfies 100 or more and 500 or less.

[0069] [Embodiment 2] Refer to Figure 4 and Figure 5 The reactor 1b of Embodiment 2 will be described. The reactor 1b of Embodiment 2 is different from the reactor 1a of Embodiment 1 in that the shape of the side core portion 33 is a stepped shape. The following description will focus on the differences from Embodiment 1. The same reference numerals are given to the same structures as those in Embodiment 1, and the description thereof will be omitted.

[0070] Refer to Figure 5, the shape of the side core part 33 in this embodiment will be described in detail. Here, the shape of the first side core part 331 will be described. The side core part 33 has a stepped shape. The so-called stepped shape means a shape having a part where the width gradually tapers from the first end 34a toward the second end 34b. The inner surface of the first side core part 331 has a stepped portion 33s. In this embodiment, the stepped portion 33s is located at the center of the length of the first side core part 331. The first side core part 331 is divided into two regions by one stepped portion 33s. The region from the first end 34a to the stepped portion 33s is the first region 341. The region from the stepped portion 33s to the second end 34b is the second region 342. The width of the second region 342 is thinner than the width of the first region 341. The inner surface of the first region 341 and the inner surface of the second region 342 are respectively parallel to the outer peripheral surface of the coil 2. The interval between the inner surface of the second region 342 and the outer peripheral surface of the coil 2 is larger than the interval between the inner surface of the first region 341 and the outer peripheral surface of the coil 2. The width of the stepped portion 33s is appropriately set so that the ratio of the first interval D1 to the second interval D2 satisfies a predetermined range. The width of the stepped portion 33s is the distance along the Y-axis direction of the stepped portion 33s. The width of the stepped portion 33s is equal to the difference between the distance from the outer peripheral surface of the coil 2 to the inner surface of the second region 342 and the distance from the outer peripheral surface of the coil 2 to the inner surface of the first region 341. That is, the width of the stepped portion 33s is represented by D2 - D1. The width of the stepped portion 33s is, for example, 1 mm or more and less than 5 mm, and further 1.25 mm or more and 4 mm or less.

[0071] In this embodiment, the number of the stepped portions 33s is one, but there may also be multiple stepped portions 33s. When the number of the stepped portions 33s is n, the number of the regions constituting the side core part 33 is n + 1. The (n + 1)-th region is the region closer to the second end 34b than the n-th region, and the width of the (n + 1)-th region is thinner than the width of the n-th region. The width gradually tapers from the first region toward the (n + 1)-th region.

[0072] The shape of the side core part 33 may also be a shape formed by combining a conical shape and a stepped shape. As a modified example of the shape of the side core part 33, for example, there are the following shapes. (1) In Figure 5 , the first region 341 may be a conical shape, and the second region 342 may be a shape without the stepped portion 33s relative to the first region 341 and having a constant width. (2) In Figure 5 , the first region 341 may be a conical shape, and the second region 342 may be a shape with the stepped portion 33s relative to the first region 341 and having a constant width. (3) In Figure 5In [this], the first region 341 may have a shape with a constant width, and the second region 342 may be a conical shape without a step portion 33s relative to the first region 341. (4) In Figure 5 [this], the first region 341 may have a shape with a constant width, and the second region 342 may have a step portion 33s relative to the first region 341 and be a conical shape.

[0073] [Embodiment 3] [Converter · Power Conversion Device] The reactor of the embodiment can be used for applications that meet the following energization conditions. The energization conditions are, for example: the maximum DC current is on the order of 100 A or more and 1000 A or less, the average voltage is on the order of 100 V or more and 1000 V or less, and the operating frequency is on the order of 5 kHz or more and 100 kHz or less. The reactor of the embodiment can typically be used as a component of a converter mounted on a vehicle such as an electric vehicle or a hybrid vehicle, and as a component of a power conversion device including the converter.

[0074] As Figure 6 shown, vehicles 1200 such as hybrid vehicles and electric vehicles include a main battery 1210, a power conversion device 1100 connected to the main battery 1210, and a motor 1220 that is driven by the supplied power from the main battery 1210 and is used for driving. The motor 1220 is typically a three-phase AC motor. The motor 1220 drives the wheels 1250 during driving and functions as a generator during regeneration. In the case of a hybrid vehicle, the vehicle 1200 further includes an engine 1300 in addition to the motor 1220. In Figure 6 [this], a socket is shown as the charging part of the vehicle 1200, but it can be configured to have a plug.

[0075] The power conversion device 1100 includes a converter 1110 connected to the main battery 1210 and an inverter 1120 connected to the converter 1110 that performs mutual conversion between DC and AC. The converter 1110 shown in this example boosts the input voltage of the main battery 1210 in the range of 200 V or more and 300 V or less to a range of 400 V or more and 700 V or less and supplies power to the inverter 1120 when the vehicle 1200 is driving. The converter 1110 steps down the input voltage output from the motor 1220 via the inverter 1120 to a DC voltage suitable for the main battery 1210 to charge the main battery 1210 during regeneration. The input voltage is a DC voltage. The inverter 1120 converts the DC boosted by the converter 1110 into a predetermined AC and supplies power to the motor 1220 when the vehicle 1200 is driving, and converts the AC output from the motor 1220 into DC and outputs it to the converter 1110 during regeneration.

[0076] AsFigure 7 As shown, the converter 1110 includes a plurality of switching elements 1111, a drive circuit 1112 that controls the operation of the switching elements 1111, and a reactor 1115, and performs conversion of the input voltage by repeating on / off operations. The conversion of the input voltage here is to perform buck-boost conversion. The switching elements 1111 use power devices such as field effect transistors and insulated gate bipolar transistors. The reactor 1115 has the following function: using the coil property that attempts to impede changes in the current flowing through the circuit, when the current attempts to increase or decrease due to the switching operation, making its change smooth. As the reactor of the embodiment, the reactor is provided. By providing the reactor of the embodiment, the losses of the power conversion device 1100 and the converter 1110 are small.

[0077] In addition to the converter 1110, the vehicle 1200 further includes a power supply converter 1150 connected to the main battery 1210, and an auxiliary power supply converter 1160 that converts the high voltage of the main battery 1210 into a low voltage. The auxiliary power supply converter 1160 is connected to the sub-battery 1230 that is the power source of the auxiliary equipment 1240 and the main battery 1210. The converter 1110 typically performs DC-DC conversion, but the power supply converter 1150 and the auxiliary power supply converter 1160 perform AC-DC conversion. There is also a reactor in the power supply converter 1150 that performs DC-DC conversion. In the reactors of the power supply converter 1150 and the auxiliary power supply converter 1160, a reactor having the same structure as the reactor of the embodiment and appropriately changed in size, shape, etc. can be used. In addition, the reactor of the embodiment can also be used in a converter that performs conversion of the input power and is only a boost converter or only a buck converter.

[0078] <Test Example 1> The inductance and losses of a reactor having the same structure as the reactor 1a of Embodiment 1 were evaluated.

[0079] In Test Example 1, reactors of Specimen No. 1-0 to Specimen No. 1-7 shown in Design Table 1 were designed. Specimen No. 1-0 to Specimen No. 1-7 are models in which the angle of the inclined surface 33t on the inner side of the side core portion 33 is changed within the range of 0° to 7°. The basic structure of the designed reactor is shown below.

[0080] (Dimensions of the magnetic core) · The length L of the magnetic core 3: 80 mm · The width W of the magnetic core 3: 65 mm · The height H of the magnetic core 3: 25 mm As Figure 1As shown, the length L is the dimension of the magnetic core 3 in the X-axis direction. The width W is the dimension of the magnetic core 3 in the Y-axis direction. The height H is the dimension of the magnetic core 3 in the Z-axis direction. (Dimensions of each core part) · Length of the middle core part 31: 53 mm · Width of the middle core part 31: 25 mm · Lengths of the first side core part 331 and the second side core part 332: 53 mm · Widths of the first side core part 331 and the second side core part 332: 9 mm · Lengths of the first end core part 35a and the second end core part 35b: 13.5 mm · Widths of the first end core part 35a and the second end core part 35b: 65 mm · Length of the gap part 31g: 2 mm The length of each core part is the dimension in the X-axis direction. The width of each core part is the dimension in the Y-axis direction. The height of each core part, i.e., the dimension in the Z-axis direction, is 25 mm.

[0081] Relative permeability of the first core 3a: 20 Relative permeability of the second core 3b: 200

[0082] The angles of the inclined surfaces of Specimens No. 1-0 to No. 1-7 are shown in Table 1. In addition, for each specimen, the first interval D1, the second interval D2, and the ratio of the first interval D1 to the second interval D2 (D1 / D2) are shown in Table 1. For Specimen No. 1-0 with an angle of 0° for the inclined surface 33t, the interval between the side core part 33 and the coil 2 is constant over the entire length of the side core part 33. That is, for Specimen No. 1-0, the ratio of the first interval D1 to the second interval D2 is 1. The first interval D1 and the second interval D2 of Specimen No. 1-0 are 2 mm each.

[0083] The inductance and loss of the reactor for each specimen are analyzed. In the analysis of inductance and loss, a commercially available electromagnetic field analysis software, namely JMAG-Designer 21.0 manufactured by JSOL Corporation, is used to perform a magnetic field transient response analysis.

[0084] (Analysis of inductance) The inductance when a current of 0 A to 400 A flows through the coil is analyzed. The maximum value of the inductance is obtained from the linked magnetic flux of the coil when the current value is 0 A. The inductance of each specimen is shown in Table 1. The inductance shown in Table 1 is expressed as a ratio with the inductance of Specimen No. 1-0 as the reference (100%).

[0085] (Analysis of loss) Analyze the losses when a DC current of 0 A, an input voltage of 300 V, an output voltage of 600 V, and a voltage with a frequency of 20 kHz are applied to the coil. Calculate the coil losses based on the magnetic flux density distribution and the current density distribution. Show the coil losses of each specimen in Table 1. The coil losses shown in Table 1 are expressed as a ratio with the coil loss of Specimen No. 1-0 as the reference (100%).

[0086] [Table 1] No.1-0 No.1-1 No.1-2 No.1-3 No.1-4 No.1-5 No.1-6 No.1-7 Angle of the inclined surface (°) 0 1 2 3 4 5 6 7 D1 (mm) 2 2 2 2 2 2 2 2 D2 (mm) 2 2.9 3.8 4.7 5.7 6.6 7.5 8.5 D1 / D2 1 0.69 0.53 0.43 0.35 0.31 0.27 0.24 Inductance (%) 100 99.1 98.2 97.2 96.1 94.9 93.6 92.0 Coil loss (%) 100 98.4 97.2 96.4 95.8 95.6 95.7 96.6

[0087] As shown in Table 1, the coil losses of Specimens No. 1-1 to No. 1-7 are reduced by more than 1% compared with the coil loss of Specimen No. 1-0. The second interval D2 of Specimens No. 1-1 to No. 1-7 is larger than the first interval D1, and the ratio of the first interval D1 to the second interval D2 is 0.70 or less. From the results of Specimens No. 1-1 to No. 1-7, it can be seen that the larger the second interval D2, that is, the smaller the ratio of the first interval D1 to the second interval D2, the easier it is to obtain the effect of reducing the coil loss. However, it can be seen that if the ratio of the first interval D1 to the second interval D2 becomes smaller, the inductance decreases compared with the inductance of Specimen No. 1-0. The inductances of Specimens No. 1-1 to No. 1-4 decrease by less than 5% compared with the inductance of Specimen No. 1-0. If the decrease in inductance is less than 5%, it can be regarded as an inductance approximately equal to that of Specimen No. 1-0. The ratio of the first interval D1 to the second interval D2 of Specimens No. 1-1 to No. 1-4 is 0.32 or more. It can be considered that the ratio of the first interval D1 to the second interval D2 that maintains the inductance well and obtains the effect of reducing the coil loss is 0.32 or more and 0.70 or less.

[0088] <Test Example 2> Evaluate the inductance and losses of a reactor having the same structure as the reactor 1b of Embodiment 2.

[0089] In Test Example 2, design reactors of Specimens No. 2-0 to No. 2-4 shown in Table 2. Specimens No. 2-0 to No. 2-4 are models in which the width of the stepped portion 33s on the inner side surface of the side core portion 33 is changed within the range of 0 mm to 5 mm. The basic structure of the designed reactors is the same as that of Test Example 1.

[0090] The widths of the stepped portions of the reactors of Specimens No. 2-0 to No. 2-4 are shown in Table 2. In addition, for each specimen, the first interval D1, the second interval D2, and the ratio of the first interval D1 to the second interval D2 (D1 / D2) are shown in Table 1. The interval between the side core portion 33 and the coil 2 of Specimen No. 2-0, for which the width of the stepped portion 33s is 0 mm, is constant over the entire length of the side core portion 33. That is, in Specimen No. 2-0, the ratio of the first interval D1 to the second interval D2 is 1. The first interval D1 and the second interval D2 of Specimen No. 2-0 are each 2 mm.

[0091] The reactors of each specimen were analyzed for inductance and loss. The inductance and coil loss in each specimen were determined in the same manner as in Test Example 1. The inductance and coil loss in each specimen are shown in Table 2. The inductance shown in Table 2 is expressed as a ratio with the inductance of Specimen No. 2-0 as a reference (100%). The coil loss shown in Table 2 is expressed as a ratio with the coil loss of Specimen No. 2-0 as a reference (100%).

[0092] [Table 2] No.2-0 No.2-1 No.2-2 No.2-3 No.2-4 Width of the stepped portion (mm) 0 1.25 2.5 3.75 5 D1 (mm) 2 2 2 2 2 D2 (mm) 2 3.25 4.5 5.75 7 D1 / D2 1 0.62 0.45 0.35 0.29 Inductance (%) 100 98.7 97.2 95.4 93.2 Coil loss (%) 100 97.7 96.5 96.1 97.5

[0093] As shown in Table 2, the coil losses of Specimens No. 2-1 to No. 2-4, when compared with the coil loss of Specimen No. 2-0, are reduced by 1% or more, and further by 2% or more. The ratio of the first interval D1 to the second interval D2 of Specimens No. 2-1 to No. 2-4 is 0.70 or less. The inductances of Specimens No. 2-1 to No. 2-3, when compared with the inductance of Specimen No. 2-0, are reduced by less than 5%. From the results of Test Example 2, it can also be considered that, in order to maintain good inductance and achieve the effect of reducing the coil loss, the ratio of the first interval D1 to the second interval D2 should be 0.32 or more and 0.70 or less. Description of Reference Numerals

[0094] 1a, 1b Reactors 2 Coil 2a First end face, 2b Second end face 3 Magnetic core 3a First core, 3b Second core 31 Intermediate core portion 31a First intermediate core portion, 31b Second intermediate core portion 31g Gap portion 32a First end, 32b Second end 33 Side core portion 331 First side core portion, 332 Second side core portion 33t Inclined surface, 33s Stepped portion 34a First end, 34b Second end 341 First region, 342 Second region 35 End core part 35a First end core part, 35b Second end core part D1 First interval, D2 Second interval L Length, W Width, H Height 1100 Power conversion device 1110 Converter, 1111 Switching element, 1112 Drive circuit 1115 Reactor, 1120 Inverter 1150 Converter for power supply device, 1160 Converter for auxiliary power supply 1200 Vehicle 1210 Main battery, 1220 Electric motor, 1230 Auxiliary battery 1240 Auxiliary equipment, 1250 Wheel 1300 Engine

Claims

1. A reactor comprising a coil and a magnetic core, The coil has a cylindrical shape, the magnetic core has a θ-shaped shape, The coil has a first end surface and a second end surface, The magnetic core comprises a first core and a second core. The first core includes a first end core portion and a side core portion, The second core comprises a second end core portion, At least one of the first core and the second core includes at least a portion of an intermediate core portion, The first end core portion is arranged to face the first end surface of the coil, The second end core portion is arranged to face the second end surface of the coil. The intermediate core is arranged in the coil, The side core portion includes a first side core portion and a second side core portion arranged in parallel with the middle core portion with the coil interposed therebetween. The relative magnetic permeability of the first core is lower than the relative magnetic permeability of the second core, The first side core portion and the second side core portion respectively have a first end coupled to the first end core portion and a second end coupled to the second end core portion. Regarding the interval between the first side core and the coil and the interval between the second side core and the coil, the second interval at the second end is larger than the first interval at the first end. A ratio of the first interval to the second interval is greater than or equal to 0.32 and less than or equal to 0.

70.

2. The reactor according to claim 1, wherein The intermediate core has a first intermediate core and a second intermediate core, The first intermediate core portion is combined with the first end core portion, The second intermediate core portion is combined with the second end core portion.

3. The reactor according to claim 2, wherein, The intermediate core portion has a gap portion between the first intermediate core portion and the second intermediate core portion.

4. The reactor according to any one of claims 1 to 3, wherein, The first side core portion and the second side core portion each have a tapered shape in which widths become thinner from the first end toward the second end.

5. The reactor according to any one of claims 1 to 3, wherein, The first side core portion and the second side core portion each have a stepped shape in which widths become narrower from the first end toward the second end.

6. The reactor according to any one of claims 1 to 5, wherein, The relative magnetic permeability of the first core is 5 or more and 50 or less.

7. The reactor according to any one of claims 1 to 6, wherein, The first core is formed of a molded body of a composite material in which soft magnetic powder is dispersed in a resin.

8. The reactor according to any one of claims 1 to 7, wherein, The relative magnetic permeability of the second core is 100 or more and 500 or less.

9. The reactor according to any one of claims 1 to 8, wherein, The second core is composed of a powder compact. 10 . A converter comprising the reactor according to claim 1 .

11. A power conversion device comprising the converter according to claim 10.

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