阅读说明：本技术 电抗器以及电力转换装置 (Reactor and power conversion device ) 是由 朝日俊行 小谷淳一 稻垣繁之 于 2020-03-19 设计创作，主要内容包括：电抗器具备：芯体；和卷绕于芯体而相互磁耦合的第一至第四线圈。第一与第二线圈的耦合系数K12、第一与第三线圈的耦合系数K13、第一与第四线圈的耦合系数K14满足K13＞K12且K13＞K14的关系,第二与第三线圈的耦合系数K23、第二与第四线圈的耦合系数K24、第三与第四线圈的耦合系数K34满足K24＞K23且K24＞K34的关系。或者,芯体的第一轴部的第二方向的宽度比第一轴部的第三方向的宽度短,第二轴部的第二方向的宽度比第二轴部的第三方向的宽度短,第三轴部的第二方向的宽度比第三轴部的第三方向的宽度短,第四轴部的第二方向的宽度比第四轴部的第三方向的宽度短。或者,从第一方向来看,交叉于第一线圈的中心轴和第四线圈的中心轴的直线与交叉于第二线圈的中心轴和第三线圈的中心轴的直线在芯体的柱部相交。该电抗器即使为低负载也难以产生电力转换效率的降低。(The reactor is provided with: a core body; and first to fourth coils wound around the core and magnetically coupled to each other. The coupling coefficient K12 of the first and second coils, the coupling coefficient K13 of the first and third coils, the coupling coefficient K14 of the first and fourth coils satisfy the relationship of K13 > K12 and K13 > K14, and the coupling coefficient K23 of the second and third coils, the coupling coefficient K24 of the second and fourth coils, the coupling coefficient K34 of the third and fourth coils satisfy the relationship of K24 > K23 and K24 > K34. Alternatively, the width of the first shaft portion of the core body in the second direction is shorter than the width of the first shaft portion in the third direction, the width of the second shaft portion in the second direction is shorter than the width of the second shaft portion in the third direction, the width of the third shaft portion in the second direction is shorter than the width of the third shaft portion in the third direction, and the width of the fourth shaft portion in the second direction is shorter than the width of the fourth shaft portion in the third direction. Alternatively, when viewed from the first direction, a straight line intersecting the central axis of the first coil and the central axis of the fourth coil intersects a straight line intersecting the central axes of the second coil and the third coil at the pillar portion of the core. This reactor is less likely to cause a reduction in power conversion efficiency even with a low load.)

1. A reactor is provided with:

a core body; and

a first coil, a second coil, a third coil and a fourth coil wound around the core and magnetically coupled to each other,

a coupling coefficient K12 of the first coil and the second coil, a coupling coefficient K13 of the first coil and the third coil, a coupling coefficient K14 of the first coil and the fourth coil satisfy the relationships of K13 > K12 and K13 > K14,

a coupling coefficient K23 of the second coil and the third coil, a coupling coefficient K24 of the second coil and the fourth coil, and a coupling coefficient K34 of the third coil and the fourth coil satisfy the relationships of K24 > K23 and K24 > K34.

2. The reactor according to claim 1, wherein,

the coupling coefficient K12, the coupling coefficient K13, and the coupling coefficient K14 satisfy the relationship of K13 > (K12+ K13+ K14)/2.

3. The reactor according to claim 1 or 2, wherein,

the coupling coefficient K12, the coupling coefficient K13, and the coupling coefficient K14 satisfy the relationship of 0.3 < (K12+ K13+ K14) < 0.7.

4. The reactor according to any one of claims 1 to 3,

a center axis of the first coil, a center axis of the second coil, a center axis of the third coil, and a center axis of the fourth coil extend in a first direction,

the first coil and the third coil are arranged in a second direction at right angles to the first direction,

the second coil and the fourth coil are arranged in the second direction,

the first coil and the second coil are arranged along a third direction at right angles to the first direction and the second direction,

the third coil and the fourth coil are arranged in the third direction,

a width of the first shaft portion in the second direction is shorter than a width of the first shaft portion in the third direction,

a width of the second shaft portion in the second direction is shorter than a width of the second shaft portion in the third direction,

a width of the third shaft portion in the second direction is shorter than a width of the third shaft portion in the third direction,

the fourth shaft portion has a width in the second direction that is shorter than a width in the third direction of the fourth shaft portion.

5. The reactor according to any one of claims 1 to 4, wherein,

a center axis of the first coil, a center axis of the second coil, a center axis of the third coil, and a center axis of the fourth coil extend in a first direction,

the first coil and the second coil are arranged in a direction at right angles to the first direction,

the first coil and the third coil are arranged in a direction at right angles to the first direction,

the first coil and the fourth coil are arranged in a direction at right angles to the first direction,

the core has:

a first shaft portion disposed inside the first coil;

a second shaft portion disposed inside the second coil;

a third shaft portion disposed inside the third coil;

a fourth shaft portion disposed inside the fourth coil; and

a columnar portion disposed outside any one of the first coil, the second coil, the third coil, and the fourth coil,

a straight line intersecting the central axis of the first coil and the central axis of the fourth coil and a straight line intersecting the central axis of the second coil and the central axis of the third coil intersect at the pillar portion, as viewed in the first direction.

6. The reactor according to claim 5, wherein,

the first coil is opposed to the third coil without interposing a magnetic body therebetween,

the second coil is opposed to the fourth coil without interposing a magnetic body therebetween,

the second coil and the fourth coil are each opposed to the first coil and the third coil with the pillar portion of the core interposed therebetween.

7. The reactor according to claim 5 or 6, wherein,

the pillar portion extends in the first direction,

the core further has:

a first connecting portion connected to one end portion in the first direction of the first shaft portion, the second shaft portion, the third shaft portion, the fourth shaft portion, and the pillar portion; and

and a second connecting portion connected to the first shaft portion, the second shaft portion, the third shaft portion, the fourth shaft portion, and the other end portion of the pillar portion in the first direction.

8. A reactor is provided with:

a core body; and

a first coil, a second coil, a third coil and a fourth coil wound around the core and magnetically coupled to each other,

a center axis of the first coil, a center axis of the second coil, a center axis of the third coil, and a center axis of the fourth coil extend in a first direction,

the first coil and the third coil are arranged in a second direction at right angles to the first direction,

the second coil and the fourth coil are arranged in the second direction,

the first coil and the second coil are arranged along a third direction at right angles to the first direction and the second direction,

the third coil and the fourth coil are aligned in the third direction,

a width of the first shaft portion in the second direction is shorter than a width of the first shaft portion in the third direction,

a width of the second shaft portion in the second direction is shorter than a width of the second shaft portion in the third direction,

a width of the third shaft portion in the second direction is shorter than a width of the third shaft portion in the third direction,

the fourth shaft portion has a width in the second direction that is shorter than a width in the third direction of the fourth shaft portion.

9. The reactor according to claim 8, wherein,

a center axis of the first coil, a center axis of the second coil, a center axis of the third coil, and a center axis of the fourth coil extend in a first direction,

the first coil and the second coil are arranged in a direction at right angles to the first direction,

the first coil and the third coil are arranged in a direction at right angles to the first direction,

the first coil and the fourth coil are arranged in a direction at right angles to the first direction,

the core has:

a first shaft portion disposed inside the first coil;

a second shaft portion disposed inside the second coil;

a third shaft portion disposed inside the third coil;

a fourth shaft portion disposed inside the fourth coil; and

a columnar portion disposed outside any one of the first coil, the second coil, the third coil, and the fourth coil,

a straight line intersecting the central axis of the first coil and the central axis of the fourth coil and a straight line intersecting the central axis of the second coil and the central axis of the third coil intersect at the pillar portion, as viewed in the first direction.

10. The reactor according to claim 9, wherein,

the first coil is opposed to the third coil without interposing a magnetic body therebetween,

the second coil is opposed to the fourth coil without interposing a magnetic body therebetween,

the second coil and the fourth coil are each opposed to the first coil and the third coil with the pillar portion of the core interposed therebetween.

11. The reactor according to claim 9 or 10, wherein,

the pillar portion extends in the first direction,

the core further has:

a first connecting portion connected to one end portion in the first direction of the first shaft portion, the second shaft portion, the third shaft portion, the fourth shaft portion, and the pillar portion; and

and a second connecting portion connected to the first shaft portion, the second shaft portion, the third shaft portion, the fourth shaft portion, and the other end portion of the pillar portion in the first direction.

12. The reactor according to any one of claims 8 to 11, wherein,

the core further has:

a first connecting portion connected to one end portion in the first direction of the first shaft portion, the second shaft portion, the third shaft portion, and the fourth shaft portion; and

and a second connecting portion connected to the other end portions of the first shaft portion, the second shaft portion, the third shaft portion, and the fourth shaft portion in the first direction.

13. The reactor according to any one of claims 8 to 12, wherein,

the shape of the core has a quadratic rotational symmetry with respect to an axis along the first direction.

14. A reactor is provided with:

a core body; and

a first coil, a second coil, a third coil and a fourth coil wound around the core and magnetically coupled to each other,

a center axis of the first coil, a center axis of the second coil, a center axis of the third coil, and a center axis of the fourth coil extend in a first direction,

the first coil and the second coil are arranged in a direction at right angles to the first direction,

the first coil and the third coil are arranged in a direction at right angles to the first direction,

the first coil and the fourth coil are arranged in a direction at right angles to the first direction,

the core has:

a first shaft portion disposed inside the first coil;

a second shaft portion disposed inside the second coil;

a third shaft portion disposed inside the third coil;

a fourth shaft portion disposed inside the fourth coil; and

a columnar portion disposed outside any one of the first coil, the second coil, the third coil, and the fourth coil,

a straight line intersecting the central axis of the first coil and the central axis of the fourth coil and a straight line intersecting the central axis of the second coil and the central axis of the third coil intersect at the pillar portion, as viewed in the first direction.

15. The reactor according to claim 14, wherein,

the first coil is opposed to the third coil without interposing a magnetic body therebetween,

the second coil is opposed to the fourth coil without interposing a magnetic body therebetween,

the second coil and the fourth coil are each opposed to the first coil and the third coil with the pillar portion of the core interposed therebetween.

16. The reactor according to claim 14 or 15, wherein,

the pillar portion extends in the first direction,

the core further has:

a first connecting portion connected to one end portion in the first direction of the first shaft portion, the second shaft portion, the third shaft portion, the fourth shaft portion, and the pillar portion; and

and a second connecting portion connected to the first shaft portion, the second shaft portion, the third shaft portion, the fourth shaft portion, and the other end portion of the pillar portion in the first direction.

17. The reactor according to any one of claims 14 to 16, wherein,

the shape of the core has a quadratic rotational symmetry with respect to an axis along the first direction.

18. A power conversion device is provided with:

the reactor of any one of claims 1 to 17; and

and a control device that controls energization to the first coil, the second coil, the third coil, and the fourth coil of the reactor.

19. The reactor according to claim 18, wherein,

the control device is configured to:

controlling energization to the first coil, the second coil, the third coil, and the fourth coil in a 2-phase drive mode in which energization is performed only to the first coil and the third coil among the first coil, the second coil, the third coil, and the fourth coil,

controlling energization of the first coil, the second coil, the third coil, and the fourth coil in a 4-phase drive mode in which energization is performed for all of the first coil, the second coil, the third coil, and the fourth coil.

Technical Field

The present disclosure relates to a reactor having a core and a power conversion device provided with the reactor.

Background

For example, patent document 1 discloses a conventional composite transformer (reactor) including a single transformer and a plurality of inductors.

Patent document 1 discloses a 3-phase magnetic coupling reactor in which 3-phase reactors are magnetically coupled to each other. The 3-phase magnetic coupling reactor includes a 3-axis core, 3 coils of each phase, and a 6-face core. The 3-axis core has projections projecting in 6 directions from the central portion along 3 axes orthogonal to each other. Each of the 3 coils of each phase is wound around each of the 3-axis cores. The 6-sided body core has a housing space capable of housing therein the 3-axis cores around which the phase coils are wound, and has 6 inner wall surfaces facing the 6 protrusions of the 3-axis cores. Patent document 1 discloses that in the 3-phase magnetic coupling reactor, space utilization efficiency can be improved.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2011-204946

Disclosure of Invention

The reactor is provided with: a core body; and first to fourth coils wound around the core and magnetically coupled to each other. The coupling coefficient K12 of the first and second coils, the coupling coefficient K13 of the first and third coils, the coupling coefficient K14 of the first and fourth coils satisfy the relationship of K13 > K12 and K13 > K14, and the coupling coefficient K23 of the second and third coils, the coupling coefficient K24 of the second and fourth coils, the coupling coefficient K34 of the third and fourth coils satisfy the relationship of K24 > K23 and K24 > K34. Alternatively, the width of the first shaft portion of the core body in the second direction is shorter than the width of the first shaft portion in the third direction, the width of the second shaft portion in the second direction is shorter than the width of the second shaft portion in the third direction, the width of the third shaft portion in the second direction is shorter than the width of the third shaft portion in the third direction, and the width of the fourth shaft portion in the second direction is shorter than the width of the fourth shaft portion in the third direction. Alternatively, when viewed in the first direction, a straight line intersecting the central axis of the first coil and the central axis of the fourth coil and a straight line intersecting the central axes of the second coil and the third coil intersect each other at the pillar portion of the core.

The reactor is less likely to cause a reduction in power conversion efficiency even with a low load.

Drawings

Fig. 1A is an external perspective view showing a state in which a part of a reactor according to an embodiment of the present disclosure is seen through.

Fig. 1B is an external perspective view of a reactor according to an embodiment.

Fig. 2 is an external perspective view of a core of a reactor according to an embodiment.

Fig. 3 is a cross-sectional view of the core shown in fig. 2 at line III-III.

Fig. 4 is a sectional view at a line IV-IV of the reactor shown in fig. 1B.

Fig. 5A is a sectional view at a line VA-VA of the reactor shown in fig. 4.

Fig. 5B is a sectional view at line VB-VB of the reactor shown in fig. 4.

Fig. 5C is a sectional perspective view of the reactor shown in fig. 4 at line VC-VC.

Fig. 6A is a sectional view of the reactor shown in fig. 4 taken along line VIA-VIA.

Fig. 6B is a cross-sectional view at line VIB-VIB of the reactor shown in fig. 4.

Fig. 6C is a sectional perspective view of the reactor shown in fig. 4 taken along line VIC-VIC.

Fig. 7A is a side view of a reactor in the embodiment.

Fig. 7B is a front view of the reactor in the embodiment.

Fig. 8 is a circuit diagram of the power conversion device according to the embodiment.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, the embodiment described below is only one of various embodiments of the present disclosure. The following embodiments may be variously modified according to design and the like if the purpose of the cost disclosure can be achieved.

(1) Summary of the invention

Fig. 1A and 1B are external perspective views of a reactor 1 according to the present embodiment. Fig. 1A shows a state in which a part of the reactor 1 is seen through. Fig. 2 is an external perspective view of the core 3 of the reactor 1. The reactor 1 includes a core 3 and a plurality of coils 2 wound around the core 3. The plurality of coils 2 includes 4 coils 21 to 24.

The reactor 1 of the present embodiment is a multiphase magnetic coupling type reactor having 2 or more phases, and has a magnetic coupling function of magnetically coupling 4 coils 2 and an inductor function of accumulating magnetic energy.

Fig. 3 is a sectional view at the line III-III of the core 3 shown in fig. 2. Fig. 4 is a sectional view at a line IV-IV of the reactor 1 shown in fig. 1B. Fig. 5A is a sectional view at a line VA-VA of the reactor 1 shown in fig. 4. Fig. 5B is a sectional view of the reactor 1 shown in fig. 4 at the line VB-VB. Fig. 5C is a sectional perspective view of the reactor 1 shown in fig. 4 at line VC-VC. Fig. 6A is a sectional view of the reactor 1 shown in fig. 4 taken along line VIA-VIA. Fig. 6B is a sectional view at line VIB-VIB of the reactor 1 shown in fig. 4. Fig. 6C is a sectional perspective view of the reactor 1 shown in fig. 4 taken along line VIC-VIC. Fig. 7A and 7B are side views of a reactor in the embodiment.

The core 3 has a rectangular frame shape, and 4 coils 2(21 to 24) are wound. The core 3 forms a magnetic circuit and magnetically couples 2 or more coils 2 to each other. The core 3 is configured to store magnetic flux generated by current flowing through the coil 2 as magnetic energy. The core 3 may be a closed magnetic circuit or may be an open magnetic circuit instead of a closed magnetic circuit.

As shown in fig. 5A to 5C and fig. 6A to 6C, the core 3 has a plurality of coupled magnetic paths. In detail, the core 3 has: a coupling magnetic path L12 passing through the inside of the coil 21 and the inside of the coil 22, a coupling magnetic path L13 passing through the inside of the coil 21 and the inside of the coil 23, and a coupling magnetic path L14 passing through the inside of the coil 21 and the inside of the coil 24. Further, the core 3 further includes: a coupling magnetic path L23 passing through the inside of the coil 22 and the inside of the coil 23, and a coupling magnetic path L24 passing through the inside of the coil 22 and the inside of the coil 24. Further, the core 3 has a coupling magnetic path L34 passing through the inside of the coil 23 and the inside of the coil 24.

In the reactor 1 of the present embodiment, the coupling coefficient K12 between the coil 21 and the coil 22, the coupling coefficient K13 between the coil 21 and the coil 23, and the coupling coefficient K14 between the coil 21 and the coil 24 satisfy the following equation (1).

K13 > K12, and K13 > K14 (1)

Further, in the reactor 1, the coupling coefficient K23 between the coil 22 and the coil 23, the coupling coefficient K24 between the coil 22 and the coil 24, and the coupling coefficient K34 between the coil 23 and the coil 24 satisfy the relationship of the following expression (2).

K24 > K23, and K24 > K34 (2)

In the reactor 1 of the present embodiment, the coupling coefficients K12, K13, K14, K23, K24, and K34 satisfy the above-described relationship, and thus even when a current flows through 2 coils 2 among the coils 21, 22, 23, and 24 in the 2-phase drive mode, the power conversion efficiency is less likely to decrease. This is because the reactor 1 obtains a high dc superposition effect by using 2 coils having a high coupling coefficient when the reactor 1 is driven in the 2-phase. Therefore, the reactor 1 can prevent the power conversion efficiency from being lowered even when a current does not flow through one or more of the plurality of coils 2, that is, even when the reactor is driven with a low load. Even if the reactor 1 of the present embodiment is driven by 4-phase driving in which the reactor is driven with a high load, that is, even if the reactor 1 is driven by currents flowing through the coils 21, 22, 23, and 24, respectively, switching loss of the semiconductor switch is less likely to occur. Therefore, the reactor 1 can obtain a magnetic coupling effect even when a large current flows, and can obtain a high dc superposition effect. Therefore, the reactor 1 can achieve high power conversion efficiency. In addition, the reactor 1 can also obtain an effect that the inductance is difficult to reduce by obtaining a direct current superposition effect.

The loss of the power conversion device includes a loss generated even in a no-load state accompanied by a loss of the switch or the like, and a loss due to the load. In a power conversion device driven by multiple phases, the number of coils driven by a current flow (hereinafter referred to as "the number of drive phases") is reduced at the time of low load, thereby reducing no-load loss and improving efficiency. The multiphase reactor cancels magnetic fluxes generated by the direct currents, thereby improving the direct current superposition characteristics and reducing the size of the reactor. However, in the reactor disclosed in patent document 1, when the load is low, if the number of coils driven by a current flowing therethrough is reduced in accordance with the load, the magnetic flux is not sufficiently cancelled, and there is a concern that the dc superimposition characteristics deteriorate and the power conversion efficiency decreases.

In contrast, as described above, the reactor 1 of the present embodiment can prevent the power conversion efficiency from being lowered even when the number of drive phases is reduced, that is, when the reactor is driven with a low load.

The coupling coefficient is a coupling coefficient of magnetic coupling between 2 coils. The ratio of the magnetic flux passing through the coupling magnetic circuit L12 to the total magnetic flux among the total magnetic fluxes generated by the coil 21 is a coupling coefficient K12 of the magnetic coupling of the coils 21 and 22. The ratio of the magnetic flux passing through the coupling magnetic circuit L13 to the total magnetic flux among the total magnetic flux generated by the coil 21 is a coupling coefficient K13 of the magnetic coupling of the coils 21 and 23. The ratio of the magnetic flux passing through the coupling magnetic circuit L14 to the total magnetic flux among the total magnetic flux generated by the coil 21 is a coupling coefficient K14 of the magnetic coupling of the coils 21 and 24. Similarly, the ratio of the magnetic flux passing through the coupling magnetic circuit L23 to the total magnetic flux among the total magnetic fluxes generated by the coil 22 is the coupling coefficient K23 of the magnetic coupling of the coils 22 and 23. The ratio of the magnetic flux passing through the coupling magnetic circuit L24 to the total magnetic flux among the total magnetic fluxes generated by the coil 22 is the coupling coefficient K24 of the magnetic coupling of the coils 22 and 24. The ratio of the magnetic flux passing through the coupling magnetic circuit L34 to the total magnetic flux among the total magnetic flux generated by the coil 24 is the coupling coefficient K34 of the magnetic coupling of the coils 23 and 24.

(2) Detailed description of the invention

(2-1) reactor

Hereinafter, the detailed configuration of the reactor 1 of the present embodiment will be described in detail with reference to fig. 1A to 7B. In fig. 1A to 7B, the structure of the coil 2 (coils 21, 22, 23, and 24) is schematically shown, and may be different from the actual number of turns. In fig. 1A to 7B, both end portions of the coil 2 (coils 21, 22, 23, 4) are not shown.

The 4 coils 2, i.e., the coils 21, 22, 23, and 24, are wound around the central axes 21C, 22C, 23C, and 24C, respectively. The central axes 21C, 22C, 23C, 24C extend in the direction D1. The coils 21, 23 are arranged in a direction D2 perpendicular to the direction D1. The coils 22, 24 are aligned in the direction D2. The coils 21, 22 are arranged in a direction D3 perpendicular to the directions D1, D2. The coils 23, 24 are arranged in the direction D3.

First, the structure of the core 3 will be described with reference to fig. 2. The core 3 has: shaft portions 301, 302, 303, 304, connecting portions 341, 342, and a column portion 35. As shown in fig. 2, the shaft portions 301, 302, 303, and 304 and the pillar portion 35 extend along the direction D1. The shaft portions 301 and 303 are aligned in the direction D2, and the shaft portions 302 and 304 are aligned in the direction D2. The shaft portions 301 and 302 are aligned in the direction D3, and the shaft portions 303 and 304 are aligned in the direction D3. The pillar portion 35 is disposed from a position between the shaft portion 301 and the shaft portion 303 to a position between the shaft portion 302 and the shaft portion 304. The column portion 35 and the shaft portion 301 are arranged in a direction perpendicular to the direction D1.

The connection portions 341, 342 are arranged at intervals along the direction D1. One end of each of the shaft portions 301, 302, 303, and 304 and the column portion 35 in the direction D1 is connected to the connection portion 341, and the other end is connected to the connection portion 342. That is, the connecting portion 341 is connected to the connecting portion 342 via the shaft portions 301, 302, 303, 304 and the pillar portion 35.

In the core 3, the coil 21 is wound around the shaft 301, the coil 22 is wound around the shaft 302, the coil 23 is wound around the shaft 303, and the coil 24 is wound around the shaft 304. The shaft portion 301 is provided inside the coil 21 and extends along the central axis 21C. The shaft portion 302 is provided inside the coil 22 and extends along the central axis 22C. The shaft portion 303 is provided inside the coil 23 and extends along the central axis 23C. The shaft portion 304 is provided inside the coil 24 and extends along the central axis 24C.

As shown in fig. 1A and 2 to 4, the shaft portions 301, 302, 303, and 304 have a cross-sectional shape perpendicular to the direction D1, which is an oblong shape extending long in the direction D3 and having arc-shaped ends in the direction D2. The cross-sectional shape of each of the shaft portions 301 to 304 is not limited to the above, and may be, for example, a rectangular shape having a peripheral edge portion at least a part of which has an arc, or other shapes such as a circular shape. Further, for example, as shown in fig. 1B, when viewed from the direction D1, the connection portions 341 and 342 each have a flat plate shape having a rectangular shape with 4 corners having circular arcs, but the present invention is not limited thereto.

The pillar portion 35 is formed from a position between the shaft portions 301 and 302 to a position between the shaft portions 303 and 304 along the direction D2. The shaft portions 301 and 303 are aligned in the direction D2, and the shaft portions 302 and 304 are aligned in the direction D2. The shaft portion 301, the pillar portion 35, and the shaft portion 302 are aligned in the direction D3, and the shaft portion 303, the pillar portion 35, and the shaft portion 304 are aligned in the direction D3.

The column portions 35 have a function of weakening magnetic coupling between the coils 2 disposed so as to sandwich the column portions 35. The pillar portion 35 can contribute to the realization of the relationship of the coupling coefficient in the present embodiment. As will be described in detail later.

In the present embodiment, the central axis 22C of the coil 22, the central axis 23C of the coil 23, and the central axis 24C of the coil 24 all extend along the direction D1 together with the central axis 21C of the coil 21. The coils 21, 22 are arranged in a direction D3 perpendicular to the direction D1, the coils 21, 23 are arranged in a direction D2 perpendicular to the direction D1, the coils 21, 24 are arranged in a direction D4 perpendicular to the direction D1, and the coils 22, 23 are arranged in a direction D5 perpendicular to the direction D1 and different from the directions D2, D3. The coils 21 and 22 are arranged in the direction D3, and the coils 23 and 24 are arranged in the direction D3. Further, the coils 21 and 23 are arranged in the direction D2, and the coils 22 and 24 are arranged in the direction D2. As shown in fig. 3, the width W1 of the shaft portions 301, 302, 303, 304 in the direction D2 is shorter than the width W2 of the shaft portions D3. Therefore, the coupling coefficients K12, K13, K14, K23, K24, and K34 of the reactor 1 can be easily adjusted, and thus, even if the number of drive phases of the plurality of coils is reduced and the reactor 1 is driven with a low load, the power conversion efficiency is less likely to decrease.

The core body 3 has, in the direction D3, an opening 351 surrounded by the shaft portions 301 and 303 and the connection portions 341 and 342 and opening in the direction D3, and an opening 352 surrounded by the shaft portions 302 and 304 and the connection portions 341 and 342 and opening in the direction D3. The openings 351, 352 are aligned in the direction D3, and the pillar portion 35 is formed between the opening 351 and the opening 352. In the opening 351, a part of the coil 21 wound around the shaft 301 passes through, and a part of the coil 23 wound around the shaft 303 passes through. In addition, in opening portion 352, part of coil 22 wound around shaft portion 302 passes through, and part of coil 24 wound around shaft portion 304 passes through.

The core 3 has through holes 361 and 362 penetrating in the direction D2. The through holes 361 and 362 are aligned in the direction D3 with the pillar portion 35 interposed therebetween. The through hole 361 is a part of the space surrounded by the shaft portions 301 and 303, the pillar portion 35, and the connection portions 341 and 342, and the through hole 362 is a part of the space surrounded by the shaft portions 302 and 304, the pillar portion 35, and the connection portions 341 and 342. Through hole 361, a part of coil 21 wound around shaft 301 and a part of coil 23 wound around shaft 303 pass. In the through hole 362, a part of the coil 22 wound around the shaft portion 302 and a part of the coil 24 wound around the shaft portion 304 pass.

In the present embodiment, the core 3 is integrally formed. The integration is not limited to the one-piece structure, and includes a structure in which a plurality of members are joined together with an adhesive or the like. Preferably, the core 3 contains a metal magnetic material. Specifically, the core 3 is formed by a magnetic powder core (dust core) made of an alloy such as iron/silicon/aluminum (Fe/Si/Al), iron/nickel (Fe/Ni), or iron/silicon (Fe/Si).

The column portion 35 of the core 3 is disposed not inside any of the coils 21, 22, 23, and 24 but outside any of the coils 21, 22, 23, and 24. The coils 21 and 23 intersect the pillar portion 35 of the core 3 and are located on the same side with respect to a plane P35 perpendicular to the direction D3. The coils 22, 24 are located on the same side and on the opposite side to the coils 21, 23 with reference to the plane P35. The coil 21 faces the coil 23 without interposing a magnetic body such as the core 3 therebetween. The coil 22 faces the coil 24 without interposing a magnetic body such as the core 3 therebetween. The coils 22 and 24 are opposed to the coils 21 and 23 with the column portions 35 interposed therebetween. Further, as shown in fig. 4, when viewed from the direction D1, a straight line S14 intersecting the central axis 21C of the coil 21 and the central axis 24C of the coil 24 intersects a straight line S23 intersecting the central axis 22C of the coil 22 and the central axis 23C of the coil 23 at the column portion 35. The straight lines S14, S23 are at right angles to the direction D1. That is, when viewed from the direction D1, a straight line S14 crossing the central axis 21C of the coil 21 and the central axis 24C of the coil 24 and perpendicular to the direction D1 and a straight line S23 crossing the central axis 22C of the coil 22 and the central axis 23C of the coil 23 and perpendicular to the direction D1 intersect at the column portion 35. Therefore, the coupling coefficients K12, K13, K14, K23, K24, and K34 of the reactor 1 can be easily adjusted, and thus, even if the reactor 1 is driven with a low load, it can be difficult to reduce the power conversion efficiency.

Further, the coupling coefficients K12, K13, K14, K23, K24, and K34 in the reactor 1 are not limited as long as the above-described expressions (1) and (2) are satisfied, and the position of the column portion 35 is not limited. In this case, a straight line intersecting the central axis 21C of the coil 21 and the central axis 24C of the coil 24 and a straight line intersecting the central axis 22C of the coil 22 and the central axis 23C of the coil 23 may not intersect with the pillar portion 35 when viewed from the direction D1.

Next, the configuration of the coils 2 (coils 21 to 24) in the reactor 1 of the present embodiment will be described.

The coil 21 is formed of a flat-angle conductive wire wound around the shaft 301 with the center axis 21C as the center. The coil 22 is formed of a flat-angle conductive wire wound around the shaft portion 302 with the center axis 22C as the center. The coil 23 is formed of a flat-angle conductive wire wound around the shaft portion 303 with the center axis 23C as the center. The coil 24 is formed of a flat-angle conductive wire wound around the shaft portion 304 with the center axis 24C as the center.

The coils 21, 22, 23, and 24 are wound in an oblong shape when viewed in the direction D1 of the center axes 21C, 22C, 23C, and 24C (see fig. 4). The number of turns of the coil 21, the number of turns of the coil 22, the number of turns of the coil 23, and the number of turns of the coil 24 are the same number as each other. The number of turns of the coil 21, the number of turns of the coil 22, the number of turns of the coil 23, and the number of turns of the coil 24 can be appropriately changed according to design. The number of turns of the coil 21, the number of turns of the coil 22, the number of turns of the coil 23, and the number of turns of the coil 24 may be different from each other. The coils 21, 22, 23, and 24 are not limited to the square conductive wires, and may be formed of conductive wires having a circular cross section.

When a current flows through at least one of the coils 2 (coils 21, 22, 23, and 24), a magnetic flux (dc magnetic flux) is generated from the coil 2 through which the current flows. The directions of the dc magnetic fluxes generated by the coils 21, 22, 23, and 24 are determined according to the winding directions of the coils 21, 22, 23, and 24 and the directions of the currents flowing through the coils 21, 22, 23, and 24, respectively. The dc magnetic flux here refers to magnetic flux generated by dc currents flowing through the coils 21, 22, 23, and 24, respectively. In the embodiment, the coils 21 and 22 are wound in the same direction.

Core 3 forms coupled magnetic paths L12, L13, L14, L23, L24, and L34 through which magnetic flux generated when coils 21, 22, 23, and 24 are energized, respectively. These coupled magnetic circuits include shaft portions 301, 302, 303, 304 and connecting portions 341, 342. The coils 21, 22 are magnetically coupled to each other by a coupling magnetic circuit L12 in the core 3. The coils 21, 23 are magnetically coupled to each other by a coupling magnetic circuit L13 in the core 3. The coils 21, 24 are magnetically coupled to each other by a coupling magnetic circuit L14 in the core 3. Further, the coils 22, 23 are magnetically coupled to each other by a coupling magnetic circuit L23 in the core 3. The coils 22, 24 are magnetically coupled to each other through a coupling magnetic circuit L24 in the core 3. The coils 23, 24 are magnetically coupled to each other by a coupling magnetic circuit L34 in the core 3. In other words, the core 3 magnetically couples the coils 21, 22 to each other, the coils 21, 23 to each other, the coils 21, 24 to each other, the coils 22, 23 to each other, the coils 22, 24 to each other, and the coils 23, 24 to each other. Therefore, in the reactor 1, at least one of the shaft portions 301, 302, 303, and 304 of the core 3 can realize an inductor function of accumulating and releasing magnetic energy generated in at least one of the coils 21, 22, 23, and 24.

Coils 21, 22, 23, and 24 are wound around shaft portions 301, 302, 303, and 304, respectively. Therefore, the magnetic flux generated by the coils 21, 22, 23, 24 passes through the plurality of magnetic paths (the shaft portions 301, 302, 303, 304, the connection portions 341, 342, and the column portions 35) in the core 3. Thus, for example, when a current flows through the coil 21 and a magnetic flux is generated from the coil 21, the coils 21 and 22 are magnetically coupled to each other, the coils 21 and 23 are magnetically coupled to each other, and the coils 21 and 24 are magnetically coupled to each other. When a current flows through the coil 22 and a magnetic flux is generated from the coil 22, the coils 22 and 23 are magnetically coupled to each other, the coils 22 and 24 are magnetically coupled to each other, and the coils 22 and 21 are magnetically coupled to each other. When a current flows through the coil 23 and a magnetic flux is generated from the coil 23, the coils 23 and 21 are magnetically coupled to each other, the coils 23 and 22 are magnetically coupled to each other, and the coils 23 and 24 are magnetically coupled to each other. When a current flows through the coil 24 and a magnetic flux is generated from the coil 24, the coils 24 and 21 are magnetically coupled to each other, the coils 24 and 22 are magnetically coupled to each other, and the coils 24 and 23 are magnetically coupled to each other. In other words, by the core 3, a magnetic coupling function of magnetically coupling 2 coils among the plurality of coils 2 to each other can be realized.

The core 3 in the reactor 1 has a plurality of magnetic paths that are paths through which magnetic fluxes from the coils 2 (the coils 21, 22, 23, and 24) pass. The core 3 has a magnetic circuit including a coupled magnetic circuit and a non-coupled magnetic circuit. The coupled magnetic circuit is a path generated by coupling of magnetic fluxes generated by the coils 21, 22, 23, and 24 with magnetic fluxes formed by other coils. The coupled magnetic circuit includes: a coupling magnetic path L12 passing through the inside of the coil 21 and the inside of the coil 22, a coupling magnetic path L13 passing through the inside of the coil 21 and the inside of the coil 23, and a coupling magnetic path L14 passing through the inside of the coil 21 and the inside of the coil 24. Furthermore, the coupled magnetic circuit further includes: a coupling magnetic path L23 passing through the inside of the coil 22 and the inside of the coil 23, a coupling magnetic path L24 passing through the inside of the coil 22 and the inside of the coil 24, and a coupling magnetic path L34 passing through the inside of the coil 23 and the inside of the coil 24. The non-coupled magnetic path is a path in which a magnetic flux generated by one coil 2 among the plurality of coils 2 is not generated and a magnetic flux formed between the coil 2 and any other coil 2 is not generated.

Specifically, for example, a magnetic path P1 (see, for example, fig. 5A to 5C) is formed in the core 3, through which magnetic flux generated when the coil 21 is energized passes in the shaft portion 301. That is, the magnetic circuit P1 is a path through which the magnetic flux generated by the coil 21 passes. Magnetic circuit P1 includes coupled magnetic circuits L12, L13, and L14.

The magnetic path P1 passes through, for example, the shaft portion 301 and the connection portion 341 inside the coil 21, the shaft portion 303 and the connection portion 342 inside the coil 23. For example, when a current flows through the coil 21, a magnetic flux Y13 is generated as shown in fig. 5A. The magnetic path P1 passes through, for example, the shaft portion 301, the connection portion 341, and the column portion 35 inside the coil 21, the shaft portion 302, and the connection portion 342 inside the coil 22. For example, when a current flows through the coil 21, magnetic fluxes Y11 and Y12 are generated as shown in fig. 5B. The magnetic path P1 passes through, for example, the shaft portion 301, the connection portion 341, and the column portion 35 inside the coil 21, the shaft portion 304, and the connection portion 342 inside the coil 24. For example, when a current flows through the coil 21, magnetic fluxes Y10 and Y14 are generated as shown in fig. 5C. That is, the path through which magnetic flux Y10, Y11, Y12, Y13, and Y14 passes is included in magnetic circuit P1. The magnetic fluxes Y10, Y11, Y12, Y13, and Y14 are conceptually illustrated, and the magnetic flux passing through the magnetic circuit P1 is not limited to this.

Further, in the core 3, a magnetic path P2 through which magnetic flux generated when the coil 22 is energized passes is formed in the shaft portion 302. That is, the magnetic circuit P2 is a path through which the magnetic flux generated by the coil 22 passes. Magnetic circuit P2 includes coupled magnetic circuits L12, L23, and L24. Magnetic path P2 passes through shaft 302, connecting portion 341, and pillar portion 35 on the inner side of coil 22, and shaft 301, and connecting portion 342 on the inner side of coil 21. The magnetic path P2 passes through the shaft portion 302, the connection portion 341, and the column portion 35 inside the coil 22, the shaft portion 303, and the connection portion 342 inside the coil 23. The magnetic path P2 passes through the shaft portion 302 and the connection portion 341 inside the coil 22, the shaft portion 304 and the connection portion 342 inside the coil 24.

Further, the core 3 forms a magnetic path P3 through which magnetic flux generated when the coil 23 is energized passes in the shaft portion 303. That is, the magnetic circuit P3 is a path through which the magnetic flux generated by the coil 23 passes. Magnetic circuit P3 includes coupled magnetic circuits L13, L24, and L34. The magnetic path P3 passes through the shaft portion 303 and the connection portion 341 inside the coil 23, the shaft portion 301 and the connection portion 342 inside the coil 21. The magnetic path P3 passes through the shaft portion 303, the connection portion 341, and the column portion 35 on the inner side of the coil 23, the shaft portion 302, and the connection portion 342 on the inner side of the coil 22. The magnetic path P3 passes through the shaft 303 and the connection portion 341 inside the coil 23, the shaft 304 and the connection portion 342 inside the coil 24.

Further, the core 3 forms a magnetic path P4 through which magnetic flux generated when the coil 24 is energized passes in the shaft portion 304. That is, the magnetic circuit P4 is a path through which the magnetic flux generated by the coil 24 passes. Magnetic circuit P4 includes coupled magnetic circuits L14, L24, and L34. Magnetic path P4 passes through shaft portion 304, connecting portion 341, and column portion 35 on the inner side of coil 24, and shaft portion 301 and connecting portion 342 on the inner side of coil 21. The magnetic path P4 passes through the shaft portion 304 and the connection portion 341 inside the coil 24, the shaft portion 302 and the connection portion 342 inside the coil 22. The magnetic path P4 passes through the shaft portion 304 and the connection portion 341 inside the coil 24, the shaft portion 303 and the connection portion 342 inside the coil 23.

Here, in the reactor 1 of the present embodiment, as described above, the coupling coefficients K12, K13, and K14 satisfy the above expression (1), and the coupling coefficients K12, K23, and K24 satisfy the above expression (2).

The coupling coefficient K13 of the coils 21, 23 is greater than the coupling coefficient K12 of the coils 21, 22 and the coupling coefficient K14 of the coils 21, 24. The coupling coefficient K24 of the coils 22 and 24 is larger than the coupling coefficients K12 of the coils 21 and 22 and K34 of the coils 23 and 24. That is, the magnetic coupling of the coils 21, 23 is stronger than the magnetic coupling of the coils 21, 22 and the coupling coefficient of the coils 21, 24. The magnetic coupling of the coils 22, 24 is stronger than the magnetic coupling of the coils 21, 22 and the coupling coefficient of the coils 23, 24. Therefore, when the reactor 1 drives the plurality of coils 2, even if the number of coils 2 to be driven is reduced and the coils 2 through which current flows are switched, a magnetic coupling effect can be obtained, a high direct current superposition effect can be obtained, and a decrease in power efficiency due to switching loss can be suppressed.

Further, the coupling coefficients K13 and K34 may satisfy the relationship of K13 > K34. Further, the coupling coefficients K24, K12 may also satisfy the relationship of K24 > K12.

In the reactor 1, the coupling coefficients K12, K13, and K14 preferably satisfy formula (3).

K13＞(K12+K13+K14)/2···(3)

In this case, the reactor 1 can further control the magnetic coupling, and can further contribute to making it difficult to reduce the power conversion efficiency. In the reactor 1, when the relation of the formula (3) is satisfied, the coupling coefficients K12, K23, and K24 satisfy the formula (3').

K24＞(K12+K23+K24)/2···(3’)

Preferably, the coupling coefficients K12, K13, K14 satisfy formula (4).

0.3＜(K12+K13+K14)＜0.7···(4)

In this case, the reactor 1 can control the magnetic coupling between the plurality of coils 2, and can contribute to further reducing the power conversion efficiency. In the reactor 1, when the formula (4) is satisfied, the coupling coefficient K12, the coupling coefficients K23, and K24 also satisfy the formula (4').

0.3＜(K12+K23+K24)＜0.7···(4’)

In the reactor 1, as the coupling coefficient increases, the magnetic flux passing through the magnetic paths P1, P2, P3, and P4 decreases, and the substantial inductance of each coil 2 decreases. Therefore, in the power conversion device described later, in order to boost the input voltage to a predetermined voltage value, it is necessary to increase the number of turns of each coil 2 (coils 21, 22, 3, and 24) and increase the inductance, for example. Further, the volume of the core 3 needs to be increased so that the core 3 (the shaft portions 301, 302, 03, 304, the connecting portions 341, 342, the pillar portion 35) is not magnetically saturated. As a result, the reactor 1 may become large.

As described above, in the reactor 1 of the present embodiment, the coupling coefficients K12, K13, K14, K23, K24, and K34 are set to satisfy the expressions (1) and (2), and thus the respective coupling coefficients can be set to be greater than 0.3 and less than 0.7. Therefore, in the reactor 1, the reduction of the inductance of each coil 2 can be suppressed, and the size of the reactor 1 can be suppressed. The parameters for determining the coupling coefficient include the length of the magnetic circuit (each coupled magnetic circuit, magnetic circuits P1 to P4), the cross-sectional area of the magnetic circuit (each coupled magnetic circuit, magnetic circuits P1 to P4), and the material forming core 3.

In the reactor 1, the coupling coefficient between the coils 2 can be adjusted by the following adjustment method, for example. However, the method of adjusting the coupling coefficient described below is an example, and is not limited thereto.

Since the coupled magnetic path L12 of the coil 21 and the coil 22 passes through the insides of both the coils 21 and 22, the magnetic path is longer than the magnetic path passing through the inside of only one coil 2 (the coils 21 and 22) of the magnetic paths P1 and P2 through which the magnetic flux generated by the coils 21 and 22 passes. Therefore, a long magnetic path length is an important factor for reducing the coupling coefficient. In the present embodiment, as described above, the reactor 1 has the coils 21 and 22 arranged in the direction D3 perpendicular to the central axes 21C and 22C of the coils 21 and 22. The coils 23 and 24 are arranged in a direction D2 perpendicular to the central axes 23C and 24C of the coils 23 and 24. The coils 22 and 24 are arranged in a direction D2 perpendicular to the central axes 22C and 24C of the coils 22 and 24. In this case, the width W2 in the direction D2 is preferably shorter than the width W1 in the direction D3 of the shaft portions 301, 302, 303, and 304.

Specifically, as shown in fig. 3, the width W1 of the shaft portions 301, 302, 303, 304 in the direction D2 is shorter than the width W2 in the direction D3. In other words, the magnetic resistance of the coupling magnetic circuit L13 is reduced by making the interval between the shaft portions 301 and 302 and the interval between the shaft portions 301 and 304 longer than the interval between the shaft portions 301 and 303, and making the coupling magnetic circuits L12 and L14 longer than the coupling magnetic circuit L13. Similarly, the magnetic resistance of the coupling magnetic circuit L23 is reduced by making the interval between the shaft portions 301 and 302 and the interval between the shaft portions 302 and 304 longer than the interval between the shaft portions 302 and 304 and making the coupling magnetic circuits L12 and L24 longer than the coupling magnetic circuit L23. This suppresses the coupling coefficients K13 and K24 from becoming too low.

The column portions 35 have a function of reducing magnetic coupling between the coils 2 disposed so as to sandwich the column portions 35, as described above. Therefore, by providing the core 3 with the pillar portions 35, for example, the coupling of the coils 21, 22 can be weakened, and the coupling of the coils 21, 24 can be weakened. The post 35 can attenuate the coupling of the coils 23, 24 and can also attenuate the coupling with the coils 22, 23. The pillar portion 35 may also contain a different material from the shaft portions 301, 302, 303, 304 in the core body 3.

(3) Modification example

Modifications are listed below. The modifications described below can be applied in appropriate combination with the above-described embodiments and modifications.

In the reactor 1 of the above embodiment, at least one of the connection portions 341 and 342, the shaft portions 301, 302, 303, and 304, and the column portion 35 are integrally formed in the core 3, but may be independent of each other. For example, in the above example, the shaft 301 is configured to serve as both the coupling magnetic circuit L12 and the magnetic circuit P1, but may be configured to be divided into a shaft forming the coupling magnetic circuit L12 and a shaft forming the magnetic circuit P1. For example, the shaft portion 302 is configured to serve as both the coupling magnetic path and the magnetic path P2, but may be configured to be divided into a shaft portion forming the coupling magnetic path and a shaft portion forming the magnetic path. In this case, the 2 shaft portions constituting the shaft portions 301(302) may be electrically joined by an adhesive or the like. Similarly, each of the shaft portions 303 and 304 may be divided into a shaft portion forming a coupling magnetic path and a shaft portion forming a magnetic path. The shaft portion 303 and the shaft portion 304 may be configured to be divided into a coupled magnetic circuit and a non-coupled magnetic circuit in the same manner.

The shaft portions 301, 302, 303, and 304 of the core 3 may be made of different materials. For example, when designing the reactor 1, the coupling coefficient may be adjusted by making the magnetic permeabilities of the material forming the shaft portions 301 and 302 and the material forming the shaft portions 303 and 304 different from each other.

The reactor 1 may further include a bobbin (bobbin). The bobbin is designed to wind the coil 2 (at least one coil selected from the group consisting of the coils 21, 22, 23, 24) and to pass at least one shaft selected from the group consisting of the shafts 301, 302, 303, 304 of the core 3.

The reactor 1 may be configured such that the coils 21, 22, 23, and 24 and the core 3 are integrally sealed by a sealing member such as resin. This can suppress winding displacement of the coils 21, 22, 23, and 24.

Further, it is preferable that the core 3 has 180 ° rotational symmetry centered on the axis along the direction D1, that is, the shape of the core 3 coincides with the shape of the core 3 rotated 180 ° centered on the axis AX3 along the direction D1. That is, the shape of the core 3 has quadratic rotational symmetry with respect to the axis AX 3. In this case, it is easy to adjust each coupling coefficient to satisfy the expressions (1) to (4). Thus, even if the number of drive phases of the plurality of coils 2 is switched, the reactor 1 can further improve the effect of suppressing the reduction in the efficiency of power conversion.

The core 3 may not have the through holes 361 and 362. For example, the core 3 may have a rectangular tubular shape without an opening portion such as the through holes 361 and 362. In the core 3, the through holes 361 and 362 may be connected to each other.

The core 3 may not have the openings 351 and 352. For example, the core 3 may have the connection portions 341 and 342, the shaft portions 301, 302, 303, and 304, and a side wall surrounding the periphery of these portions.

The number of the plurality of coils 2 is not limited to 4, and may be 5 or more.

(4) Power conversion device

Fig. 8 is a circuit diagram of a power conversion device 100 including the reactor 1 of the present embodiment. The power conversion device 100 is installed in an automobile, a residential or non-residential power conditioner, an electronic device, and the like.

The power conversion device 100 of the present embodiment includes the reactor 1 described above, and a control device 141 that controls energization of the opposing coils 21, 22, 23, and 24. The configuration of the power converter 100 is not limited to the following description.

The power conversion device 100 of the present embodiment is a multi-phase boost chopper circuit that outputs an output voltage Vo obtained by boosting an input voltage Vi. The power conversion device 100 includes: reactor 1, 4 switching elements 111, 112, 113, 114, 4 diodes 121, 122, 123, 124, capacitor 131, and control device 141. A higher potential is applied to the input terminal 151 than to the input terminal 152.

In the power converter 100 of the present embodiment, a dc input voltage Vi is applied between the pair of input terminals 151 and 152. Between the pair of input terminals 151, 152, 4 series circuits 71A to 74A are electrically connected in parallel with each other. The series circuit 71A includes the coil 21 of the reactor 1 and the switching element 111 connected in series with each other. The series circuit 72A includes the coil 22 of the reactor 1 and the switching element 112 connected in series with each other. The series circuit 73A includes the coil 23 of the reactor 1 and the switching element 113 connected in series with each other. The series circuit 74A includes the coil 24 of the reactor 1 and the switching element 114 connected in series with each other. In the embodiment, the coils 21 and 22 are wound in the same direction. One end of each of the coils 21 and 22 is electrically connected to the high-potential-side input terminal 151 of the power conversion device 100.

As described above, the coils 21, 22, 23, and 24 are magnetically coupled to each other via the core 3.

The switching elements 111, 112, 113, and 114 include, for example, a mosfet (metal Oxide Semiconductor Field Effect transistor). One end of the switching element 111 is electrically connected to the high-potential-side input terminal 151 via the coil 21, and the other end is electrically connected to the low-potential-side input terminal 152. One end of the switching element 112 is electrically connected to the high-potential-side input terminal 151 via the coil 22, and the other end is electrically connected to the low-potential-side input terminal 152. One end of the switching element 113 is electrically connected to the high-potential-side input terminal 151 via the coil 23, and the other end is electrically connected to the low-potential-side input terminal 152. One end of the switching element 114 is electrically connected to the high-potential-side input terminal 151 via the coil 24, and the other end is electrically connected to the low-potential-side input terminal 152. The switching elements 111, 112, 113, and 114 are turned on and off in accordance with a signal transmitted from the control device 141.

A series circuit 71B including a diode 121 and a capacitor 131 connected in series with each other is electrically connected between both ends of the switching element 111. Between both ends of the switching element 112, a series circuit 72B including a diode 122 and a capacitor 131 connected in series with each other is electrically connected. Between both ends of the switching element 113, a series circuit 73B including a diode 123 and a capacitor 131 connected in series with each other is electrically connected. Between both ends of the switching element 114, a series circuit 74B including a diode 124 and a capacitor 131 connected in series with each other is electrically connected. In other words, between both ends of the capacitor 131, a series circuit 71C including the switching element 111 and the diode 121 connected in series with each other, a series circuit 72C including the switching element 112 and the diode 122 connected in series with each other, a series circuit 73C including the switching element 113 and the diode 123 connected in series with each other, and a series circuit 74C including the switching element 114 and the diode 124 connected in series with each other are electrically connected in parallel with each other.

The capacitor 131 is a smoothing capacitor and is electrically connected between the pair of output terminals 161 and 162. Diode 121 has an anode electrically connected to connection point N1 at which coil 21 is connected to switching element 111, and a cathode electrically connected to capacitor 131. Diode 122 has an anode electrically connected to connection point N2 at which coil 22 is connected to switching element 112, and a cathode electrically connected to capacitor 131. The anode of the diode 123 is electrically connected to a connection point N3 at which the coil 23 is connected to the switching element 113, and the cathode is electrically connected to the capacitor 131. Diode 124 has an anode electrically connected to connection point N4 at which coil 24 is connected to switching element 114, and a cathode electrically connected to capacitor 131.

The control device 141 is configured to control the switching elements 111, 112, 113, and 114 to be turned on or off directly or via a drive circuit. The control device 141 controls the on/off of the switching elements 111, 112, 113, and 114, thereby controlling the currents flowing through the coils 21, 22, 23, and 24, respectively.

When the switching element 111 is turned on, a current flows through the coil 21, and magnetic energy is accumulated in the core 3. When the switching element 111 is turned off, the magnetic energy stored in the core 3 is released, and a current flows through the capacitor 131, thereby charging the capacitor 131.

The operation when the switching elements 112, 113, and 114 are turned on and off is the same as the operation when the switching element 111 is turned on and off, and magnetic energy is accumulated in the core 3 to charge the capacitor 131. The switching elements 111, 112, 113, and 114 are turned on and off, thereby generating an output voltage Vo that boosts the input voltage Vi between both ends of the capacitor 131.

The control device 141 of the present embodiment has a drive mode including a 2-phase drive mode and a 4-phase drive mode. That is, the drive modes of the control device 141 include, for example, a 2-phase drive mode and a 4-phase drive mode.

In the 4-phase drive mode, the control device 141 performs control of energizing all of the coils 21, 22, 23, and 24. Specifically, the control device 141 controls the switching elements such that the switching elements 111, 112, 113, and 114 are turned on in sequence, for example. In this case, the controller 141 controls the switching elements 111, 112, 113 and the element 114 so that the phases of the currents flowing through the coils 21, 22, 23 and 24 are shifted by 90 °. Thereby, the control device 141 can realize a 4-phase drive mode for driving the 4 coils 21, 22, 23, and 24.

The power conversion device 100 of the present embodiment can reduce the number of coils to be driven from the 4-phase drive mode described above. The power conversion apparatus 100 can be driven in a 2-phase drive mode, for example.

In the 2-phase drive mode, the controller 141 can perform control such that only the coils 21, 23 among the coils 21, 22, 23, 24 are alternately energized and the coils 23, 24 are not energized. Further, although the coils 21, 23 are alternately energized, a time period may be generated in which both the coils 21, 23 are energized simultaneously. Thereby, the control device 141 can realize the 2-phase drive mode. In this case, the control device 141 may select 2 coils 2 of the 4 coils 2 having a strong magnetic coupling. For example, although the control device 141 has been described as performing control such that only the coils 21 and 23 among the coils 21 to 24 are alternately energized and no current is applied to the coils 22 and 24, the control device may perform control such that only the coils 22 and 24 among the coils 21 to 24 are alternately energized and no current is applied to the coils 21 and 23. The combination of coils to be energized by the control device 141 can be selected as appropriate.

In the 2-phase drive mode, controller 141 may turn on an element group including 2 switching elements among 4 switching elements 111, 112, and 113 alternately. The control device 141 may turn on 2 switching elements 111 and 112 among 4 switching elements 111 to 114 and turn off the other 2 switching elements 113 and 114, for example. Next, the switching elements 111, 112 are turned off, and 2 switching elements 113, 114 are turned on while the other 2 switching elements 111, 112 are turned off. These operations are alternately repeated, and the control device 141 controls the switching elements 111, 112, 113, and 114. In this case, the controller 141 controls the switching elements 111, 112, 113, and 114 so that the phases of the currents flowing through the coils 21 and 22 are shifted by 180 ° from the phases of the currents flowing through the coils 23 and 24. Thus, the control device 141 can realize 2-phase driving for driving 2 coils in the group of coils 21 and 22 and the group of coils 23 and 24.

In the power conversion device 100 including the reactor 1 having 4 coils 2, for example, the control device 141 that controls the currents flowing through the 4 coils is preferably configured such that the phases of the currents flowing through the 4 coils 2 are shifted by 90 ° from each other.

The configuration of the electric circuit in the power conversion device 100 including the reactor 1 is not limited to the multi-phase boost chopper circuit (see fig. 8).

As described above, in the power conversion device 100 of the present embodiment, in the case of the 2-phase driving, the capacitor 131 is repeatedly charged and discharged at a period 2 times as long as the switching period of the switching elements 111 and 112. In the case of 4-phase driving, the power conversion device 100 can repeatedly charge and discharge the capacitor 131 at a period 4 times the switching period of the switching elements 111 and 112. This enables the power conversion device 100 to reduce the size of the capacitor 131. Further, the power conversion device 100 of the present embodiment is difficult to reduce the power conversion efficiency even in the case of 2-phase driving. Therefore, the power conversion device 100 including the reactor 1 can be suitably used for applications such as automobiles, power regulators for residential use or non-residential use, and electronic devices.

The reactor 1 can suppress an increase in size, and the power conversion device 100 can obtain inductance of each coil 2 that boosts the input voltage Vi to a predetermined voltage value.

-description of symbols-

1 reactor

2 coil

21 Loop (first loop)

22 coil (second coil)

23 coil (third coil)

24 coil (fourth coil)

3 core body

35 column part

301 shaft part (first shaft part)

302 axle part (second axle part)

303 shaft part (third shaft part)

304 shaft part (fourth shaft part)

100 power conversion device

141 control the device.