Reactors, converters, and power conversion devices

Abstract

To provide a reactor capable of reducing loss of a coil.SOLUTION: A reactor includes a coil and a magnetic core, wherein the magnetic core includes a first core and a second core, the first core includes a first end core part and a side core part, the second core includes a second end core part, at least one of the first core and the second core includes at least a part of a middle core part, the middle core part is arranged in the coil, the side core part is arranged in parallel with the middle core part so as to sandwich the coil, the relative permeability of the first core is lower than the relative permeability of the second core, the side core part has a first end bonded to the first end core part and has a second end bonded to the second end core part, a second interval between the side core part and the coil at the second end is larger than a first interval between the side core part and the coil at the first end, and a ratio of the first interval to the second interval is 0.32 or more and 0.70 or less.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a reactor, a converter, and a power conversion device.

Background Art

[0002] A reactor is included in a component of a converter mounted on a vehicle such as a hybrid vehicle. The reactor includes a coil and a magnetic core. The reactor described in FIGS. 5 to 8 of Patent Document 1 includes one coil and a magnetic core formed by combining two core pieces. This magnetic core is a so-called E-E type core composed of two E-shaped core pieces. This magnetic core is configured in a θ shape by combining the end faces of the two core pieces to face each other. The magnetic core has an end core portion, a middle core portion, and a side core portion. The end core portion is arranged to face the end face of the coil. The middle core portion is arranged inside the coil. The side core portion is arranged in parallel with the middle core portion so as to sandwich the coil.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is desirable to reduce the loss of the coil due to leakage magnetic flux from the magnetic core.

[0005] One object of the present disclosure is to provide a reactor capable of reducing the loss of the coil.

Means for Solving the Problems

[0006] The reactor of the present disclosure includes a coil having a cylindrical shape and a magnetic core having a θ shape, The coil has a first end face and a second end face, 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 includes a second end core portion, At least one of the first core and the second core includes at least a part of the middle 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 middle core portion is arranged within the coil. The side core portion has a first side core portion and a second side core portion that are arranged in parallel with the middle core portion so as to sandwich the coil. The relative permeability of the first core is lower than that of the second core. The first side core portion and the second side core portion each have a first end connected to the first end core portion and a second end connected to the second end core portion, The distance between the first side core portion and the coil, and the distance between the second side core portion and the coil, are such that the second distance at the second end is greater than the first distance at the first end. The ratio of the first interval to the second interval is 0.32 or more and 0.70 or less. [Effects of the Invention]

[0007] The reactor of this disclosure can reduce coil losses. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic perspective view showing a reactor according to Embodiment 1. [Figure 2] Figure 2 is a schematic plan view showing a reactor according to Embodiment 1. [Figure 3]FIG. 3 is a schematic plan view showing half of the reactor shown in FIG. 2. [Figure 4] FIG. 4 is a schematic plan view showing the reactor according to Embodiment 2. [Figure 5] FIG. 5 is a schematic plan view showing half of the reactor shown in FIG. 4. [Figure 6] FIG. 6 is a configuration diagram schematically showing a power supply system of a hybrid vehicle. [Figure 7] FIG. 7 is a circuit diagram schematically showing a power conversion device including a converter.

Mode for Carrying Out the Invention

[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described.

[0010] (1) The reactor of the present disclosure includes a coil having a cylindrical shape and a magnetic core having 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 a middle 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 middle 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 middle core portion so as to sandwich the coil, the relative permeability of the first core is lower than the relative permeability of the second core, The first side core portion and the second side core portion each have a first end coupled to the first end core portion and a second end coupled to the second end core portion. The distance between the first side core portion and the coil, and the distance between the second side core portion and the coil are each larger at the second end than at 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.

[0011] The reactor of the present disclosure can reduce the loss of the coil. When the relative permeability of the side core portion is low and the relative permeability of the second end core portion is high, there is a possibility that leakage magnetic flux that short-circuits from the side core portion to the second end core portion may occur in the vicinity of the second end. When this leakage magnetic flux links with the coil, loss occurs in the coil. According to the reactor of the present disclosure, since the second interval at the second end is larger than the first interval at the first end, leakage magnetic flux linking with the coil can be suppressed. Since the leakage magnetic flux to the coil decreases, the loss of the coil can be reduced. Since the ratio of the first interval to the second interval is 0.70 or less, the leakage magnetic flux to the coil is sufficiently suppressed, so that the loss of the coil can be effectively reduced. In particular, when the ratio of the first interval to the second interval is 0.32 or more and 0.70 or less, the loss of the coil can be effectively reduced while suppressing a decrease in inductance.

[0012] Since the magnetic characteristics of the first core and the second core are different, the magnetic characteristics of the entire magnetic core can be adjusted. Since the relative permeability of the first core is lower than the relative permeability of the second core, a predetermined inductance can be easily obtained.

[0013] (2) In the reactor according to (1) above, The middle core portion has a first middle core portion and a second middle core portion. The first middle core portion is coupled to the first end core portion. The second middle core portion may be coupled to the second end core portion.

[0014] The configuration described in (2) above allows for different magnetic properties between the first middle core and the second middle core. This configuration allows for adjustment of the overall magnetic properties of the magnetic core.

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

[0016] The configuration described in (3) above allows the magnetic properties of the entire magnetic core to be adjusted by the gap.

[0017] (4) In any of the reactors described in (1) to (3) above, The first side core portion and the second side core portion may each have a tapered shape, becoming narrower in width from the first end to the second end.

[0018] The configuration described in (4) above makes it easier to reduce coil losses.

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

[0020] The configuration described in (5) above makes it easier to reduce coil losses.

[0021] (6) In any of the reactors described in (1) to (5) above, The relative permeability of the first core may be 5 or more and 50 or less.

[0022] The configuration described in (6) above makes it easy to obtain the desired inductance.

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

[0024] Generally, the relative permeability of molded composite materials is low. The configuration described in (7) above makes it easy to create a magnetic core in which the relative permeability of the first core is lower than that of the second core. Because the first core is made of a molded composite material, it is easy to adjust the relative permeability of the first core to, for example, between 5 and 50.

[0025] (8) In any of the reactors described in (1) to (7) above, The relative permeability of the second core may be 100 or more and 500 or less.

[0026] The configuration described in (8) above makes it easy to obtain the desired inductance.

[0027] (9) In any of the reactors described in (1) to (8) above, The second core may be made of a compacted powder body.

[0028] Generally, compacted powder bodies have high relative permeability. The configuration described in (9) above makes it easy to create a magnetic core in which the relative permeability of the first core is lower than that of the second core. Because the second core is made of compacted powder, it is easy to adjust the relative permeability of the second core to, for example, between 100 and 500.

[0029] (10) The converters of this disclosure It comprises a reactor as described in any one of (1) to (9) above.

[0030] The converter of this disclosure has low losses because it is equipped with the reactor of this disclosure.

[0031] (11) The power converter of the present disclosure is The device is equipped with the converter described in (10) above.

[0032] The power conversion device of this disclosure has low losses because it is equipped with a converter of this disclosure.

[0033] [Details of the embodiments of this disclosure] Specific examples of embodiments of the present disclosure will be described below with reference to the drawings. Identical reference numerals in the drawings indicate identical parts. The present invention is not limited to these examples, but is as defined by the claims, and all modifications within the meaning and scope equivalent to the claims are intended.

[0034] [Embodiment 1] [Reactor] The reactor 1a of Embodiment 1 will be described with reference to Figures 1 to 3. The reactor 1a comprises a coil 2 and a magnetic core 3. The magnetic core 3 comprises a first core 3a and a second core 3b. As shown in Figure 2, 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 a middle core portion 31, a side core portion 33, and an end core portion 35. Figure 1 is a perspective view of the reactor 1a seen from above. Figure 2 is a plan view of the reactor 1a seen from above. Figure 3 is a partial plan view showing only half of the reactor 1a shown in Figure 2.

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

[0036] In reactor 1a, the loss of coil 2 can be reduced because the second spacing D2 is larger than the first spacing D1. In particular, by having a ratio D1 / D2 of 0.32 to 0.70 between the first spacing D1 and the second spacing D2, the loss of coil 2 can be effectively reduced while suppressing the decrease in inductance. The configuration of reactor 1a will be described in detail below.

[0037] <coil> As shown in Figures 1 and 2, coil 2 is positioned in the middle core portion 31 of the magnetic core 3. Coil 2 has a cylindrical shape. Coil 2 has a first end face 2a and a second end face 2b. In this embodiment, coil 2 is an edgewise coil formed by winding a flat wire edgewise.

[0038] The shape of coil 2 may be polygonal or cylindrical. A polygonal shape means that the contour shape of the end face of coil 2 is polygonal. Polygonal shapes include, for example, quadrilaterals, hexagons, and octagons. A quadrilateral includes a rectangular shape. A rectangular shape includes a square shape. A quadrilateral is not limited to geometric quadrilaterals, but also includes shapes formed by connecting four corners. That is, it includes quadrilaterals with modifications to the details, such as shapes where the four corners are rounded by chamfering, or shapes where the four corners are chamfered in a straight line. A cylindrical shape means that the contour shape of the end face of coil 2 is circular. A circular shape includes not only a perfect circle but also an ellipse. In this embodiment, the shape of coil 2 is rectangular.

[0039] <Magnetic core> As shown in Figures 1 and 2, the magnetic core 3 has a middle core portion 31, a side core portion 33, and an end core portion 35. In Figures 2 and 3, the boundaries between the middle core portion 31 and the end core portion 35, and the boundaries between the side core portion 33 and the end core portion 35 are shown by dashed lines. This is also the case in Figures 4 and 5, which will be described later. As shown in Figure 2, the magnetic core 3 has a θ-shaped form in plan view.

[0040] In the following explanation, the X-axis, Y-axis, and Z-axis directions are defined as follows: The X-axis direction is the direction along the axis of coil 2, from the first end face 2a to the second end face 2b. The Y-axis direction is the direction in which the middle core portion 31 and the side core portion 33 are arranged in parallel, from the middle core portion 31 to the side core portion 33. The Y-axis direction is perpendicular to the X-axis direction. The direction from the middle core portion 31 to the first side core portion 331 is defined as the Y1 direction. The direction from the middle core portion 31 to the second side core portion 332 is defined as the Y2 direction. The Z-axis direction is perpendicular to both the X-axis and Y-axis directions. shaft The direction is from bottom to top, assuming the XY plane, which includes the X and Y axes, is horizontal.

[0041] The magnetic core 3 forms a θ-shaped closed magnetic path. When coil 2 is energized, magnetic flux flows through the magnetic core 3. The magnetic flux generated by coil 2 flows from the middle core section 31, through the end core section 35 and the side core section 33, and back to the middle core section 31. The dashed arrows in Figure 2 indicate the flow of magnetic flux. This is also true in Figure 4, which will be described later.

[0042] (Middle core section) The middle core portion 31 is positioned inside the coil 2, as shown in Figure 2. There is one middle core portion 31. The middle core portion 31 extends in the X-axis direction. The direction along the length of the middle core portion 31 coincides with the direction along the axis of the coil 2. The length of the middle core portion 31 is the same as or greater than the length of the coil 2. Here, length refers to the distance along the X-axis direction. Both ends of the middle core portion 31 may protrude from both end faces of the coil 2. These protruding portions are also part of the middle core portion 31. The shape of the middle core portion 31 corresponds to the shape of the inside of the coil 2. In this embodiment, the shape of the middle core portion 31 is approximately a rectangular parallelepiped.

[0043] The middle core portion 31 is positioned 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 middle core portion 31 has a first end 32a and a second end 32b. The first end 32a is connected to the first end core portion 35a. The second end 32b is connected to the second end core portion 35b.

[0044] In this embodiment, the middle core portion 31 has a first middle core portion 31a and a second middle core portion 31b. The first middle core portion 31a and the second middle core portion 31b are arranged in series along the X-axis direction. The boundary between the first middle core portion 31a and the second middle core portion 31b is located within the coil 2. The first middle core portion 31a includes a first end 32a that is coupled to the first end core portion 35a. The second middle core portion 31b includes a second end 32b that is coupled to the second end core portion 35b. Coupled means that they are attached and cannot be separated. The first middle core portion 31a and the first end core portion 35a may be molded as a single unit. If the first middle core portion 31a and the first end core portion 35a are separate independent parts, for example, the first end 32a may be bonded to the first end core portion 35a, or at least parts of the first middle core portion 31a and the first end core portion 35a may be integrated by being covered with a resin mold. The second middle core portion 31b and the second end core portion 35b may be molded as a single unit. If the second middle core portion 31b and the second end core portion 35b are separate independent parts, for example, the second end 32b may be bonded to the second end core portion 35b, or at least a portion of the second middle core portion 31b and the second end core portion 35b may be integrated by being covered by a resin mold. The resin mold is a series of molded members formed to cover at least a portion of each of the first core 3a and the second core 3b. In this embodiment, the first middle core portion 31a and the first end core portion 35a are molded as a single unit. The second middle core portion 31b and the second end core portion 35b are molded as a single unit.

[0045] The lengths of the first middle core section 31a and the second middle core section 31b can be set as appropriate. In this embodiment, the lengths of the first middle core section 31a and the second middle core section 31b are different. The first middle core section 31a may be longer than the second middle core section 31b. The first middle core section 31a may be shorter than the second middle core section 31b. The lengths of the first middle core section 31a and the second middle core section 31b may be the same.

[0046] In this embodiment, the middle core portion 31 has a gap portion 31g. The gap portion 31g is provided between the first middle core portion 31a and the second middle core portion 31b. The inductance can be adjusted by having a gap portion 31g in the middle core portion 31. The gap portion 31g is located inside the coil 2. When the gap portion 31g is located inside the coil 2, the leakage flux from the gap portion 31g is reduced compared to when the gap portion 31g is exposed from the coil 2. Therefore, it is easier to suppress the leakage flux from the gap portion 31g from linking with the coil 2. Losses caused by leakage flux from the gap portion 31g can be reduced. The length of the gap portion 31g is set appropriately so that a predetermined inductance can be obtained. The length of the gap portion 31g is, for example, 0.1 mm to 3 mm, 0.3 mm to 2.5 mm, and further 0.5 mm to 2 mm. The gap portion 31g may be an air gap. The gap portion 31g may be made of a non-magnetic material, such as resin or ceramics. When the middle core portion 31 has a gap portion 31g, the length of the middle core portion 31 is the sum of the length of the first middle core portion 31a, the length of the second middle core portion 31b, and the length of the gap portion 31g. The gap portion 31g is optional. When there is no gap portion 31g, the first middle core portion 31a and the second middle core portion 31b are in contact with each other, and there is substantially no gap between the first middle core portion 31a and the second middle core portion 31b.

[0047] (End core section) The end core portion 35 is positioned outside the coil 2, as shown in Figure 2. The end core portion 35 is positioned to face both end faces of the coil 2. There are two end core portions 35. The end core portion 35 has 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 spaced apart in the X-axis direction. The first end core portion 35a and the second end core portion 35b each have inner surfaces that face each other. The first end core portion 35a faces the first end face 2a of the coil 2. The first end 32a of the middle core portion 31 is connected 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 middle core portion 31 is connected 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 form a predetermined magnetic path. In this embodiment, the shapes of the first end core portion 35a and the second end core portion 35b are substantially rectangular parallelepipeds.

[0049] (Side core section) The side core section 33 is positioned outside the coil 2, as shown in Figure 2. The side core section 33 is positioned in parallel with the middle core section 31, sandwiching the coil 2. There are two side core sections 33. The side core section 33 extends in the X-axis direction. The direction along the length of the side core section 33 is parallel to the direction along the length of the middle core section 31. The length of the side core section 33 is equal to the length of the middle core section 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 spaced apart in the Y-axis direction. The first side core portion 331 is positioned away from the middle core portion 31 in the Y1 direction. The second side core portion 332 is positioned away from the middle core portion 31 in the Y2 direction. In this embodiment, the first side core portion 331 and the second side core portion 332 are positioned symmetrically with respect to the center line of the middle core portion 31.

[0051] The first side core portion 331 and the second side core portion 332 are positioned 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 connected to the first end core portion 35a. The second end 34b is connected to the second end core portion 35b.

[0052] In this embodiment, the side core portion 33 and the first end core portion 35a are molded together. The side core portion 33 and the first end core portion 35a may be separate parts. In this case, for example, the first end 34a may be bonded to the first end core portion 35a, or at least a portion of the side core portion 33 and the first end core portion 35a may be integrated by being covered with a resin mold. In this embodiment, the side core portion 33 and the second end core portion 35b are separate parts. The side core portion 33 and the second end core portion 35b are integrated by a resin mold (not shown). The second end 34b of the side core portion 33 may be bonded to the second end core portion 35b.

[0053] <Spacing between the side core and the coil> In this embodiment, the distance between the first side core portion 331 and the coil 2, and the distance between the second side core portion 332 and the coil 2, are not constant along the X-axis. That is, the distance between the side core portion 33 and the coil 2 is not constant along the entire length of the side core portion 33. The distance between the side core portion 33 and the coil 2 increases from the first end 34a to the second end 34b. The distance between the side core portion 33 and the coil 2 refers to the distance between the inner surface of the side core portion 33 and the outer surface of the coil 2. The inner surface of the side core portion 33 is the surface facing the outer surface of the coil 2.

[0054] Referring to Figure 3, the spacing between the side core portion 33 and the coil 2 will be explained in detail. Figure 3 shows only half of the reactor 1a shown in Figure 2, divided into two parts by the center line of the middle core portion 31, including the first side core portion 331. Here, referring to Figure 3, the spacing between the first side core portion 331 and the coil 2 will be explained, but the spacing between the second side core portion 332 and the coil 2 is similar. The spacing between the first side core portion 331 and the coil 2 is such that the second spacing D2 at the second end 34b is larger than the first spacing D1 at the first end 34a. The first spacing D1 refers to the spacing between the inner surface of the first side core portion 331 located at the first end 34a and the virtual surface that is an extension of the outer surface of the coil 2. If the corner between the end face and the inner surface of the first end 34a is chamfered, it is considered as if there is no chamfer. In other words, the spacing between the corner between the extended surface of the end face and the extended surface of the inner surface of the first end 34a and the above-mentioned virtual surface is considered to be the first spacing D1. The second interval D2 refers to the distance between the inner surface of the first side core portion 331 located at the second end 34b and a virtual surface that is an extension of the outer surface of the coil 2. If the corner between the end face of the second end 34b and the inner surface is chamfered, it is considered as if there is no chamfer. In other words, the distance between the corner between the extended surface of the end face of the second end 34b and the extended surface of the inner surface and the above-mentioned virtual surface is considered to be the second interval D2.

[0055] The ratio of the first spacing D1 to the second spacing D2 is between 0.32 and 0.70. The ratio of the first spacing D1 to the second spacing D2 is expressed as D1 / D2. The smaller the ratio D1 / D2, the larger the second spacing D2. The larger the second spacing D2, the larger the gap between the side core portion 33 and the coil 2 in the region near the second end 34b. Therefore, it is possible to suppress leakage flux that short-circuits from the side core portion 33 towards the second end core portion 35b in the region near the second end 34b, linking with the coil 2. Since the leakage flux to the coil 2 is reduced, the losses of the coil 2 can be reduced. Because the ratio D1 / D2 is 0.70 or less, the leakage flux to the coil 2 is sufficiently suppressed, and the losses of the coil 2 can be effectively reduced. If the ratio D1 / D2 becomes too small, i.e., the second spacing D2 becomes too large, the inductance may decrease, and it may become difficult to obtain the desired inductance. Ratio D1 / D2 but A ratio of 0.32 or higher makes it easier to suppress the decrease in inductance. The ratio D1 / D2 may also be between 0.35 and 0.70, or between 0.40 and 0.60.

[0056] <Shape of the side core section> The side core portion 33 has a shape in which the width of the side core portion 33 tapers from the first end 34a to the second end 34b. The side core portion 33 only needs to have a width at the second end 34b that is narrower than the width at the first end 34a. The side core portion 33 only needs to have a portion between the first end 34a and the second end 34b in which the width tapers, and may also have a portion between the first end 34a and the second end 34b in which the width is constant. The width of the side core portion 33 is the dimension of the side core portion 33 in the Y-axis direction. In this embodiment, the shape of the first side core portion 331 and the shape of the second side core portion 332 are symmetrical with respect to the center line of the middle core portion 31.

[0057] Referring to Figure 3, the shape of the side core portion 33 in this 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. A tapered shape is a shape that has a portion that becomes continuously narrower in width from the first end 34a to the second end 34b. In this embodiment, the first side core portion 331 is formed in a tapered shape along 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 circumferential surface of the coil 2. The inclined surface 33t is inclined so as to move away from the outer circumferential surface of the coil 2 from the first end 34a to the second end 34b. The angle of the inclined surface 33t with respect to the outer circumferential surface of the coil 2 is set appropriately so that the ratio of the first interval D1 to the second interval D2 satisfies a predetermined range. The angle of the inclined surface 33t is the angle between the inclined surface 33t and the outer circumferential surface of the coil 2. corner This refers to degrees. The outer surface of 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 moreover, 2° or more and 4° or less.

[0058] (First core, second core) As shown in Figure 2, the magnetic core 3 is composed of a first core 3a and a second core 3b. In this embodiment, the first core 3a has an E-shape, and the second core 3b has a T-shape. In other words, the magnetic core 3 is an ET type consisting of an E-shaped first core 3a and a 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 this embodiment, the first core 3a has a first end core portion 35a, a first middle core portion 31a, a first side core portion 331, and a second side core portion 332. The first middle core portion 31a, the first end core portion 35a, the first side core portion 331, and the second side core portion 332 are integrally molded. Since the first core 3a is an integrally molded product, each core portion constituting the first core 3a is made of the same material. That is, the magnetic properties of each core portion constituting the first core 3a are substantially the same. The shape of the first core 3a is E-shaped in plan view.

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

[0061] At least one of the first core 3a and the second core 3b includes at least a portion of the middle core portion 31. The first core 3a may have the entire middle core portion 31. If the first core 3a has the entire middle core portion 31, the second core 3b has only the second end core portion 35b. In this case, the shape of the second core 3b is I-shaped in plan view. The second core 3b may have the entire middle core portion 31. If the second core 3b has the entire middle core portion 31, the first core 3a consists 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 plan view.

[0062] <First core, second relative permeability> The relative permeability of the first core 3a is lower than that of the second core 3b. In other words, in the magnetic core 3, the relative permeability of the side core portion 33 is lower than that of the second end core portion 35b. The relative permeability of the first core 3a and the second core 3b are set appropriately so that a predetermined inductance can be obtained while satisfying the above relationship. For example, the relative permeability of the first core 3a is 5 or more and 50 or less. For example, the relative permeability of the second core 3b is 50 or more and 500 or less. If the relative permeability of the first core 3a is within the range of 5 or more and 50 or less, and the relative permeability of the second core 3b is within the range of 50 or more and 500 or less, a predetermined inductance can be easily obtained. The relative permeability of the first core 3a may 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 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 be between 50 and 450, or even between 100 and 400.

[0063] The relative permeability can be determined as follows: 。 Ring-shaped measurement samples are cut from the first core 3a and the second core 3b, respectively. Each measurement sample is wound with 300 turns on the primary side and 20 turns on the secondary side. The initial magnetization curve of the backbone (BH) is measured in the range H=0 (Oe) to 100 (Oe), and the maximum value of B / H in this initial BH magnetization curve is determined. This maximum value is taken as the relative permeability. The magnetization curve referred to here is the so-called DC magnetization curve.

[0064] <Materials of the first and second cores> The first core 3a and the second core 3b are each composed of molded bodies of soft magnetic material. The molded bodies are, for example, powder compacts or molded bodies of composite materials. The first core 3a and the second core 3b are composed of molded bodies of different materials. Different materials include not only cases where the materials of the individual components in each molded body constituting the first core 3a and the second core 3b are different, but also cases where the materials of the individual components are the same, but the content of the components is different. For example, even if the first core 3a and the second core 3b are composed of powder compacts, they are different materials if at least one of the materials and content of the soft magnetic powder constituting the powder compacts is different. Similarly, even if the first core 3a and the second core 3b are composed of molded bodies of composite materials, they are different materials if at least one of the materials and content of the soft magnetic powder constituting the composite material is different.

[0065] The compacted article is formed by compressing and molding raw material powder containing soft magnetic powder. The compacted article has a higher soft magnetic powder content compared to molded articles made of composite materials. Therefore, the compacted article has higher magnetic properties compared to molded articles made of composite materials. Magnetic properties include, for example, relative permeability and saturation magnetic flux density. The compacted article may contain, for example, at least one of a binder resin and a molding aid. The soft magnetic powder content in the compacted article is, for example, 85% to 99.99% by volume when the compacted article is considered to be 100% by volume.

[0066] A molded composite material is formed by dispersing soft magnetic powder in a resin. The molded composite material is obtained by filling a mold with a fluid material containing dispersed soft magnetic powder in an unsolidified resin, and then solidifying the resin. The content of soft magnetic powder in the molded composite material can be easily adjusted. Therefore, the magnetic properties of the molded composite material are easily controlled. The content of soft magnetic powder in the molded composite material is, for example, 20% to 80% by volume, when the molded composite material is considered to be 100% by volume.

[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 on the outer circumference of the soft magnetic metal particles, and soft magnetic nonmetal 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 is, for example, a phosphate. The soft magnetic nonmetal is, for example, ferrite.

[0068] In this embodiment, the first core 3a is made of a molded composite material, and the second core 3b is made of a compacted powder molded body. By having the first core 3a made of a molded composite material and the second core 3b made of a compacted powder molded body, the magnetic properties of the entire magnetic core 3 can be adjusted. Furthermore, when the first core 3a is made of a molded composite material, the relative permeability of the first core 3a is more likely to be between 5 and 50. When the second core 3b is made of a compacted powder molded body, the relative permeability of the second core 3b is more likely to be between 100 and 500.

[0069] [Embodiment 2] The reactor 1b of Embodiment 2 will be described with reference to Figures 4 and 5. The reactor 1b of Embodiment 2 differs from the reactor 1a of Embodiment 1 in that the shape of the side core portion 33 is stepped. The following description will focus on the differences from Embodiment 1. Components similar to those in Embodiment 1 are denoted by the same reference numerals and their description is omitted.

[0070] Referring to Figure 5, the shape of the side core portion 33 in this embodiment will be described in detail. Here, the shape of the first side core portion 331 will be described. The side core portion 33 has a stepped shape. A stepped shape is a shape that has a portion in which the width gradually narrows from the first end 34a to the second end 34b. The inner surface of the first side core portion 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 portion 331. The first side core portion 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 narrower 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 parallel to the outer surface of the coil 2. The distance between the inner surface of the second region 342 and the outer surface of the coil 2 is greater than the distance between the inner surface of the first region 341 and the outer surface of the coil 2. The width of the stepped portion 33s is set appropriately 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 corresponds to 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 surface of the coil 2 to the inner surface of the second region 342 and the distance from the outer surface of the coil 2 to the inner surface of the first region 341. In other words, the width of the stepped portion 33s is expressed as D2-D1. The width of the stepped portion 33s is, for example, 1 mm or more and less than 5 mm, and moreover, 1.25 mm or more and 4 mm or less.

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

[0072] The shape of the side core portion 33 may be a combination of a tapered shape and a stepped shape. Examples of variations in the shape of the side core portion 33 include the following shapes. (1) In Figure 5, the first region 341 may be tapered, and the second region 342 may have no step portion 33s relative to the first region 341 and have a constant width. (2) In Figure 5, the first region 341 may be tapered, and the second region 342 may have a stepped portion 33s relative to the first region 341 and a constant width. (3) In Figure 5, the first region 341 has a shape with a constant width, and the second region 342 does not have a stepped portion 33s relative to the first region 341 and may have a tapered shape. (4) In Figure 5, the first region 341 has a shape with a constant width, and the second region 342 may have a stepped portion 33s relative to the first region 341 and may also have a tapered shape.

[0073] [Embodiment 3] [Converter / Power Conversion Device] The reactor of this embodiment can be used for applications that meet the following energizing conditions. These conditions include, for example, a maximum DC current of approximately 100A to 1000A, an average voltage of approximately 100V to 1000V, and an operating frequency of approximately 5kHz to 100kHz. The reactor of this embodiment can typically be used as a component of a converter mounted on vehicles such as electric vehicles and hybrid vehicles, and as a component of a power conversion device equipped with this converter.

[0074] As shown in Figure 6, a vehicle 1200 such as a hybrid vehicle or electric vehicle includes a main battery 1210, a power converter 1100 connected to the main battery 1210, and a motor 1220 that is driven by power supplied from the main battery 1210 and used for driving. The motor 1220 is typically a three-phase AC motor. The motor 1220 drives the wheels 1250 when driving and functions as a generator during regeneration. In the case of a hybrid vehicle, the vehicle 1200 is equipped with an engine 1300 in addition to the motor 1220. In Figure 6, an inlet is shown as the charging point of the vehicle 1200, but it can also be equipped with a plug.

[0075] The power converter 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. In this example, the converter 1110 boosts the input voltage of the main battery 1210, which is approximately 200V to 300V, to approximately 400V to 700V when the vehicle 1200 is running, and supplies power to the inverter 1120. During regeneration, 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, thereby charging the main battery 1210. The input voltage is a DC voltage. When the vehicle 1200 is running, the inverter 1120 converts the DC voltage boosted by the converter 1110 into a predetermined AC voltage and supplies power to the motor 1220. During regeneration, it converts the AC output from the motor 1220 into DC voltage and outputs it to the converter 1110.

[0076] As shown in Figure 7, the converter 1110 comprises a plurality of switching elements 1111, a drive circuit 1112 that controls the operation of the switching elements 1111, and a reactor 1115, and converts the input voltage by repeatedly switching ON / OFF. In this case, the input voltage conversion is step-up or step-down. Power devices such as field-effect transistors and insulated-gate bipolar transistors are used as switching elements 1111. The reactor 1115 utilizes the property of a coil that tries to oppose changes in the current that is about to flow through the circuit, and has the function of smoothing the change when the current tries to increase or decrease due to the switching operation. The reactor 1115 is the reactor of the embodiment. By including the reactor of the embodiment, the losses of the power converter 1100 and the converter 1110 are small.

[0077] Vehicle 1200 includes, in addition to converter 1110, a power supply device converter 1150 connected to the main battery 1210, and an auxiliary power converter 1160 connected to the main battery 1210 and a sub-battery 1230 which serves as a power source for auxiliary equipment 1240, and which converts the high voltage of the main battery 1210 to low voltage. Converter 1110 typically performs DC-DC conversion, while the power supply device converter 1150 and the auxiliary power converter 1160 perform AC-DC conversion. Some power supply device converters 1150 also perform DC-DC conversion. The reactors of the power supply device converter 1150 and the auxiliary power converter 1160 have the same configuration as the reactor in the embodiment, and reactors with appropriately changed size or shape can be used. Furthermore, the reactor in the embodiment can also be used in a converter that converts input power, such as a converter that only boosts voltage or a converter that only bucks voltage.

[0078] <Test Example 1> The inductance and loss were evaluated for a reactor with a configuration similar to reactor 1a of Embodiment 1.

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

[0080] (Magnetic core size) • Magnetic core 3 length L: 80mm • Magnetic core 3 width: W: 65mm • Height of magnetic core 3: H: 25mm Length L is the dimension of the magnetic core 3 in the X-axis direction, as shown in Figure 1. Width W is the dimension of the magnetic core 3 in the Y-axis direction. Height H is the dimension of the magnetic core 3 in the Z-axis direction. (Size of each core section) • Middle core section 31 Length: 53mm • Width of the middle core section 31: 25mm • Length of each of the first side core section 331 and the second side core section 332: 53 mm • Width of each of the first side core section 331 and the second side core section 332: 9 mm • Length of the first end core section 35a and the second end core section 35b: 13.5 mm • Width of each of the first end core section 35a and the second end core section 35b: 65 mm • Length of gap section (31g): 2mm The length of each core section is the dimension in the X-axis direction. The width of each core section is the dimension in the Y-axis direction. The height of each core section, 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] Table 1 shows the angles of the inclined surfaces for samples No. 1-0 to No. 1-7. Table 1 also shows the first interval D1, the second interval D2, and the ratio of the first interval D1 to the second interval D2 (D1 / D2) for each sample. In sample No. 1-0, where the angle of the inclined surface 33t is 0°, the distance between the side core section 33 and the coil 2 is constant along the entire length of the side core section 33. That is, in sample No. 1-0, the ratio of the first interval D1 to the second interval D2 is 1. In sample No. 1-0, both the first interval D1 and the second interval D2 are 2 mm.

[0083] For each sample reactor, the inductance and loss were analyzed. For the inductance and loss analysis, JMAG-Designer 21.0, a commercially available electromagnetic field analysis software from JSOL Corporation, was used to perform magnetic field transient response analysis.

[0084] (Analysis of inductance) The inductance was analyzed when a current from 0A to 400A was passed through a coil. The maximum inductance was determined from the flux linkage of the coil when the current value was 0A. The inductance for each sample is shown in Table 1. The inductances shown in Table 1 are expressed as a ratio with the inductance of sample No. 1-0 as the reference (100%).

[0085] (Analysis of losses) The losses were analyzed when a DC current of 0A, input voltage of 300V, output voltage of 600V, and frequency of 20kHz were applied to a coil. The coil losses were determined from the magnetic flux density distribution and current density distribution. The coil losses for each sample are shown in Table 1. The coil losses shown in Table 1 are expressed as a ratio with the coil loss of sample No. 1-0 as the baseline (100%).

[0086] [Table 1]

[0087] As shown in Table 1, the coil losses of samples No. 1-1 to No. 1-7 are reduced by more than 1% compared to the coil loss of sample No. 1-0. For samples No. 1-1 to No. 1-7, the second spacing D2 is larger than the first spacing D1, and the ratio of the first spacing D1 to the second spacing D2 is 0.70 or less. From the results for samples No. 1-1 to No. 1-7, it can be seen that the larger the second spacing D2, that is, the smaller the ratio of the first spacing D1 to the second spacing D2, the easier it is to reduce coil losses. However, it can be seen that when the ratio of the first spacing D1 to the second spacing D2 becomes smaller, the inductance decreases compared to the inductance of sample No. 1-0. The inductance of samples No. 1-1 to No. 1-4 is less than 5% lower than the inductance of sample No. 1-0. If the decrease in inductance is less than 5%, it can be considered to be approximately the same inductance as sample No. 1-0. Samples No. 1-1 to No. 1-4 have a ratio of 0.32 or higher between the first spacing D1 and the second spacing D2. It is considered that the ratio of the first spacing D1 to the second spacing D2 that maintains good inductance while reducing coil losses is between 0.32 and 0.70.

[0088] <Test Example 2> The inductance and loss were evaluated for a reactor with a configuration similar to reactor 1b of Embodiment 2.

[0089] In Test Example 2, reactors for samples No. 2-0 to No. 2-4, shown in Table 2, were designed. Samples No. 2-0 to No. 2-4 are models in which the width of the stepped portion 33s on the inner surface of the side core portion 33 is changed within a range from 0 mm to 5 mm. The basic configuration of the designed reactor is the same as in Test Example 1.

[0090] Table 2 shows the width of the stepped sections in the reactors of samples No. 2-0 to No. 2-4. For each sample, the first interval D1, the second interval D2, and the ratio of the first interval D1 to the second interval D2 (D1 / D2) are also shown. 2 As shown below, in sample No. 2-0, where the width of the stepped portion 33s is 0 mm, the distance between the side core portion 33 and the coil 2 is constant along the entire length of the side core portion 33. In other words, in sample No. 2-0, the ratio of the first distance D1 to the second distance D2 is 1. In sample No. 2-0, the first distance D1 and the second distance D2 are both 2 mm.

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

[0092] [Table 2]

[0093] As shown in Table 2, the coil losses of samples No. 2-1 to No. 2-4 are reduced by more than 1%, and even more than 2%, compared to the coil loss of sample No. 2-0. For samples No. 2-1 to No. 2-4, the ratio of the first spacing D1 to the second spacing D2 is 0.70 or less. The inductance of samples No. 2-1 to No. 2-3 is reduced by less than 5% compared to the inductance of sample No. 2-0. From the results of Test Example 2, it is considered that the ratio of the first spacing D1 to the second spacing D2 that maintains good inductance while reducing coil losses is between 0.32 and 0.70. [Explanation of symbols]

[0094] 1a, 1b Reactor 2 coils 2a first end face, 2b second end face 3 Magnetic core 3a First core, 3b Second core 31 Middle Core Section 31a First middle core section, 31b Second middle core section 31g gap 32a first end, 32b second end 33 Side core section 331 First side core section, 332 Second side core section 33t slope, 33s step 34a first end, 34b second end 341 first area, 342 second area 35 End core section 35a First end core section, 35b Second end core section D1 first interval, D2 second interval L Length, W Width, H Height 1100 Power converter 1110 Converter, 1111 Switching element, 1112 Drive circuit 1115 Reactor, 1120 Inverter 1150 Converter for power supply equipment, 1160 Converter for auxiliary power supply equipment 1200 vehicles 1210 Main battery, 1220 Motor, 1230 Sub-battery 1240 Auxiliary equipment, 1250 Wheels 1300 engine

Claims

1. It comprises a coil having a cylindrical shape and a magnetic core having a θ-shaped shape, The coil has a first end face and a second end face, 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 includes a second end core portion, At least one of the first core and the second core includes at least a part of the middle 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 middle core portion is arranged within the coil. The side core portion has a first side core portion and a second side core portion that are arranged in parallel with the middle core portion so as to sandwich the coil. The relative permeability of the first core is lower than that of the second core. The first side core portion and the second side core portion each have a first end connected to the first end core portion and a second end connected to the second end core portion, The distance between the first side core portion and the coil, and the distance between the second side core portion and the coil, are such that the second distance at the second end is greater than the first distance at the first end. The ratio of the first interval to the second interval is 0.32 or more and 0.70 or less. Reactor.

2. The middle core section comprises a first middle core section and a second middle core section. The first middle core portion is coupled to the first end core portion. The reactor according to claim 1, wherein the second middle core portion is coupled to the second end core portion.

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

4. The reactor according to claim 1, wherein the first side core portion and the second side core portion each have a tapered shape that narrows in width from the first end to the second end.

5. The reactor according to claim 1, wherein the first side core portion and the second side core portion each have a stepped shape that narrows in width from the first end to the second end.

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

7. The reactor according to claim 1, wherein the first core is composed of a molded body of a composite material in which soft magnetic powder is dispersed in a resin.

8. The reactor according to claim 1, wherein the relative permeability of the second core is 100 or more and 500 or less.

9. The reactor according to claim 1, wherein the second core is made of a compacted powder molded body.

10. A reactor comprising the reactor described in any one of claims 1 to 9, converter.

11. A converter according to claim 10, Power converter.

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