Conductor for high-frequency current

Abstract

To provide a conductor for a high-frequency current capable of further reducing a resistance loss per mass.SOLUTION: A conductor for a high frequency current includes: a tabular first conductor part extending in a predetermined direction; a tabular second conductor part extending in the predetermined direction, and disposed aligned with the first conductor part with a spacing in a width direction; a tabular third conductor part extending in the predetermined direction, and disposed at the upside of the first conductor part with a spacing in a vertical direction; and a tabular fourth conductor part extending in the predetermined direction, disposed aligned with the third conductor part with a spacing in the width direction, and disposed at the upside of the second conductor part with a spacing in the vertical direction, where the third conductor part intersects the first conductor part at the upside of the first conductor part, and the fourth conductor part intersects the second conductor part at the upside of the second conductor part.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a conductor for high-frequency current.

Background Art

[0002] In a high-power power converter accompanied by high-frequency current, the cross-sectional area of the conductor used in the main circuit is designed from the viewpoint of current-carrying capacity in consideration of resistance loss mainly due to the skin effect. For this reason, a thin and wide conductor is used for the purpose of reducing the skin effect.

[0003] However, in a thin and wide conductor, it is difficult for high-frequency current to flow in the middle part in the width direction of the conductor, and there is still room for improvement in the resistance loss per unit mass of the conductor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Embodiments of the present invention provide a conductor for high-frequency current that can further reduce the resistance loss per unit mass.

Means for Solving the Problems

[0006] According to an embodiment of the present invention, a plate-shaped first conductor part extending in a predetermined direction, a plate-shaped second conductor part extending in the predetermined direction and arranged side by side with the first conductor part at an interval in the width direction, a plate-shaped third conductor part extending in the predetermined direction and arranged above the first conductor part at an interval in the vertical direction, and a plate-shaped fourth conductor part extending in the predetermined direction, arranged side by side with the third conductor part at an interval in the width direction, and arranged above the second conductor part at an interval in the vertical direction are provided. The first conductor part, the second conductor part, the third conductor part, and the fourth conductor part extend in the predetermined direction and have a bent part that bends in the width direction. The bending direction of the bent part of the second conductor part is opposite to the bending direction of the bent part of the first conductor part. The first conductor part and the second conductor part have a first part in which the interval in the width direction between the first conductor part and the second conductor part is set to a first interval, and a second part in which the interval in the width direction between the first conductor part and the second conductor part is set to a second interval wider than the first interval. The bending direction of the bent part of the fourth conductor part is opposite to the bending direction of the bent part of the third conductor part. The third conductor part and the fourth conductor part have a third part in which the interval in the width direction between the third conductor part and the fourth conductor part is set to a third interval, and a fourth part in which the interval in the width direction between the third conductor part and the fourth conductor part is set to a fourth interval narrower than the third interval. The third conductor part and the fourth conductor part arrange the third part above the first part and the fourth part above the second part. The third conductor part intersects the first conductor part above the first conductor part, and the fourth conductor part intersects the second conductor part above the second conductor part. A conductor for high-frequency current is provided.

Effect of the Invention

[0007] A conductor for high-frequency current that can further reduce the resistance loss per unit mass is provided.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

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Figure 4

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Figure 8

Figure 9

Figure 10

[0009] Hereinafter, each embodiment will be described with reference to the drawings. Note that the drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of the sizes between parts, etc. are not necessarily the same as those in reality. Also, even when representing the same part, the dimensions and ratios may be represented differently in the drawings. In the present specification and each drawing, the same reference numerals are given to the same elements as those described above with respect to the already shown drawings, and the detailed description will be omitted as appropriate.

[0010] FIG. 1 is a perspective view schematically showing a conductor for high-frequency current according to an embodiment. FIG. 2 is a plan view schematically showing a conductor for high-frequency current according to an embodiment. As shown in FIGS. 1 and 2, the conductor 10 for high-frequency current includes a first conductor portion 11, a second conductor portion 12, a third conductor portion 13, and a fourth conductor portion 14. Note that the high-frequency current is, for example, an alternating current of 100 Hz or more.

[0011] The first conductor portion 11 is a plate-shaped conductor extending in a predetermined direction. The second conductor portion 12 is a plate-shaped conductor that extends in the same predetermined direction as the first conductor portion 11 and is arranged side by side with the first conductor portion 11 with a gap in the width direction.

[0012] The third conductor portion 13 is a plate-shaped conductor that extends in the same predetermined direction as the first conductor portion 11 and the second conductor portion 12 and is arranged above the first conductor portion 11 with a gap in the vertical direction. The fourth conductor portion 14 extends in the same predetermined direction as the first conductor portion 11 to the third conductor portion 13, is arranged side by side with the third conductor portion 13 with a gap in the width direction, and is arranged above the second conductor portion 12 with a gap in the vertical direction.

[0013] Note that in this specification, the vertical direction is, in other words, the thickness direction of the plate-shaped first conductor portion 11 to the fourth conductor portion 14. The vertical direction is, in other words, the direction orthogonal to the widest surface (main surface) of the plate-shaped first conductor portion 11 to the fourth conductor portion 14. The width direction is, more specifically, the direction in which the first conductor portion 11 to the fourth conductor portion 14 extend and the direction orthogonal to the vertical direction. The width direction is, in other words, the short-side direction when the direction in which the first conductor portion 11 to the fourth conductor portion 14 extend is taken as the longitudinal direction.

[0014] The plate shape means, for example, a shape in which the length in the predetermined direction in which the first conductor portion 11 to the fourth conductor portion 14 extend is longer than the length in the width direction, and the length in the width direction (width) is longer than the length in the thickness direction (thickness). In the first conductor portion 11 to the fourth conductor portion 14, the length in the predetermined direction in which they extend is, for example, more than twice as long as the length in the width direction. Also, in the first conductor portion 11 to the fourth conductor portion 14, the length in the width direction is, for example, more than twice as long as the length in the thickness direction.

[0015] The conductor 10 further includes, for example, a pair of supports 21 and 22. The support 21 supports one end of each of the first conductor part 11 to the fourth conductor part 14 in the longitudinal direction (a predetermined direction). The support 22 supports the other end of each of the first conductor part 11 to the fourth conductor part 14 in the longitudinal direction. The supports 21 and 22 are, for example, plate-like members having substantially the same thickness. The first conductor part 11 and the second conductor part 12 are, for example, attached to the lower surfaces of the supports 21 and 22. The third conductor part 13 and the fourth conductor part 14 are, for example, attached to the upper surfaces of the supports 21 and 22. Thereby, each of the first conductor part 11 to the fourth conductor part 14 can be held in a state of being arranged at intervals as described above.

[0016] For the first conductor part 11 to the fourth conductor part 14 and the pair of supports 21 and 22, a metal material with high conductivity such as copper is used, for example. However, the materials of the first conductor part 11 to the fourth conductor part 14 and the pair of supports 21 and 22 are not limited to this, and any material having at least conductivity may be used.

[0017] However, the conductor 10 does not necessarily have to include the pair of supports 21 and 22. The first conductor part 11 to the fourth conductor part 14 may be configured to be attached to a device such as another conductor or a power converter in a state of being arranged at intervals as described above.

[0018] The first conductor part 11 to the fourth conductor part 14 extend in a predetermined direction and have bent portions 11a to 14a that bend in the width direction. The first conductor part 11 to the fourth conductor part 14 have bent portions 11a to 14a that bend in the width direction between a pair of plate-like portions extending in a predetermined direction. In other words, the shape of the first conductor part 11 to the fourth conductor part 14 is a shape in which a pair of plate-like portions extending in a predetermined direction are connected by a portion extending in the width direction.

[0019] The first conductor part 11 to the fourth conductor part 14 are, for example, plate-shaped and bent in a substantially S shape in the width direction. In other words, the first conductor part 11 to the fourth conductor part 14 are plate-shaped and bent in a crank shape in the width direction. In other words, when viewed from above, the first conductor part 11 to the fourth conductor part 14 are plate-shaped and have a portion bent (curved or bent) in the width direction.

[0020] The bending direction of the bent portion 12a of the second conductor part 12 is opposite to the bending direction of the bent portion 11a of the first conductor part 11. As a result, the first conductor part 11 and the second conductor part 12 have a first portion P1 in which the widthwise interval between the first conductor part 11 and the second conductor part 12 is set to a first interval S1, and a second portion P2 in which the widthwise interval between the first conductor part 11 and the second conductor part 12 is set to a second interval S2 wider than the first interval S1.

[0021] Similarly, the bending direction of the bent portion 14a of the fourth conductor part 14 is opposite to the bending direction of the bent portion 13a of the third conductor part 13. As a result, the third conductor part 13 and the fourth conductor part 14 have a third portion P3 in which the widthwise interval between the third conductor part 13 and the fourth conductor part 14 is set to a third interval S3, and a fourth portion P4 in which the widthwise interval between the third conductor part 13 and the fourth conductor part 14 is set to a fourth interval S4 narrower than the third interval S3.

[0022] The third conductor part 13 and the fourth conductor part 14 arrange the third portion P3 above the first portion P1 and the fourth portion P4 above the second portion P2. In this way, the third conductor part 13 and the fourth conductor part 14 are arranged by interchanging the positional relationship between the narrow part and the wide part with the first conductor part 11 and the second conductor part 12.

[0023] As a result, the third conductor part 13 intersects the first conductor part 11 above the first conductor part 11. The fourth conductor part 14 intersects the second conductor part 12 above the second conductor part 12. The third conductor part 13 intersects the bent portion 11a of the first conductor part 11, for example, at the bent portion 13a. The fourth conductor part 14 intersects the bent portion 12a of the second conductor part 12, for example, at the bent portion 14a.

[0024] The fourth interval S4 is, for example, substantially the same as the first interval S1. The third interval S3 is, for example, substantially the same as the second interval S2. The shapes of the first conductor portion 11 to the fourth conductor portion 14 are, for example, substantially the same. For example, by arranging the conductors formed in the same shape with their directions reversed, the first conductor portion 11 to the fourth conductor portion 14 are configured. In this way, by enabling the use of a common member for the first conductor portion 11 to the fourth conductor portion 14, the manufacturing of the conductor 10 can be facilitated as compared with the case where the shapes of the first conductor portion 11 to the fourth conductor portion 14 are different. For example, the manufacturing cost of the conductor 10 can be suppressed.

[0025] However, the shapes of the first conductor portion 11 to the fourth conductor portion 14 do not necessarily have to be the same. The fourth interval S4 may be different from the first interval S1. The third interval S3 may be different from the second interval S2.

[0026] FIG. 3 is a cross-sectional view schematically showing a part of a conductor for high-frequency current according to an embodiment. FIG. 3 schematically shows a cross-section taken along line A1 - A2 in FIG. 2. As shown in FIG. 3, in the first portion P1, the outer end S11 in the width direction of the first conductor portion 11 is disposed at a position overlapping the third conductor portion 13 in the vertical direction. In other words, in the first portion P1, the outer end S11 in the width direction of the first conductor portion 11 is located below the third conductor portion 13.

[0027] Here, the outer end S11 in the width direction of the first conductor portion 11 is an end located on the side opposite to the second conductor portion 12 in the first conductor portion 11. Conversely, the inner end in the width direction of the first conductor portion 11 is an end located on the side of the second conductor portion 12 (the side facing the second conductor portion 12) in the first conductor portion 11. The relationship between the inner and outer sides in the second conductor portion 12 to the fourth conductor portion 14 is the same.

[0028] In the first part P1, the outer end S21 in the width direction of the second conductor part 12 is arranged at a position overlapping with the fourth conductor part 14 in the vertical direction. In other words, in the first part P1, the outer end S21 in the width direction of the second conductor part 12 is located below the fourth conductor part 14.

[0029] In the third part P3, the inner end S31 in the width direction of the third conductor part 13 is arranged at a position overlapping with the first conductor part 11 in the vertical direction. In other words, in the third part P3, the inner end S31 in the width direction of the third conductor part 13 is located above the first conductor part 11.

[0030] In the third part P3, the inner end S41 in the width direction of the fourth conductor part 14 is arranged at a position overlapping with the second conductor part 12 in the vertical direction. In other words, in the third part P3, the inner end S41 in the width direction of the fourth conductor part 14 is located above the second conductor part 12.

[0031] FIG. 4 is a cross-sectional view schematically showing a part of the conductor for high-frequency current according to the embodiment. FIG. 4 schematically shows a cross-section taken along line B1 - B2 in FIG. 2. As shown in FIG. 4, in the second part P2, the inner end S12 in the width direction of the first conductor part 11 is arranged at a position overlapping with the third conductor part 13 in the vertical direction. In other words, in the second part P2, the inner end S12 in the width direction of the first conductor part 11 is located below the third conductor part 13.

[0032] In the second part P2, the inner end S22 in the width direction of the second conductor part 12 is arranged at a position overlapping with the fourth conductor part 14 in the vertical direction. In other words, in the second part P2, the inner end S22 in the width direction of the second conductor part 12 is located below the fourth conductor part 14.

[0033] In the fourth part P4, the outer end S32 in the width direction of the third conductor part 13 is arranged at a position overlapping the first conductor part 11 in the vertical direction. In other words, in the fourth part P4, the outer end S32 in the width direction of the third conductor part 13 is located above the first conductor part 11.

[0034] In the fourth part P4, the outer end S42 in the width direction of the fourth conductor part 14 is arranged at a position overlapping the second conductor part 12 in the vertical direction. In other words, in the fourth part P4, the outer end S42 in the width direction of the fourth conductor part 14 is located above the second conductor part 12.

[0035] However, the configuration of each end of the first conductor part 11 to the fourth conductor part 14 is not limited to the above. Each end S11, S12 of the first conductor part 11 does not necessarily have to be located below the third conductor part 13. Each end S21, S22 of the second conductor part 12 does not necessarily have to be located below the fourth conductor part 14. Each end S31, S32 of the third conductor part 13 does not necessarily have to be located above the first conductor part 11. Each end S41, S42 of the fourth conductor part 14 does not necessarily have to be located above the second conductor part 12.

[0036] FIG. 5 is an explanatory diagram schematically showing an example of the simulation result of the conductor for high-frequency current according to the embodiment. FIGS. 6 to 9 are explanatory diagrams schematically showing an example of the simulation result of the reference conductor. FIGS. 5 to 9 schematically show an example of the simulation result of the current density distribution when a current is passed through the conductor. In FIGS. 5 to 9, the current density distribution is represented by shading, with the portion having a high current density flowing through the conductor shown in a light color and the portion having a low current density flowing through the conductor shown in a dark color.

[0037] For the conductor of a large power converter, a copper flat plate with a substantially rectangular cross-section is usually used from the viewpoints of the manufacturing cost and assembly cost of the conductor, and it has a high current-carrying capacity in low-frequency current and is designed to have low losses.

[0038] FIG. 6 is an example of a simple simulation of the current density distribution when a low-frequency current flows through a reference conductor with a substantially rectangular cross-section. FIG. 7 is an example of a simple simulation of the current density distribution when a high-frequency current flows through the same reference conductor. The reference conductors in FIGS. 6 and 7 are, in other words, wide and thin flat plate-shaped conductors.

[0039] In a power converter with high-frequency current, the main circuit conductor is also required to have low loss. However, as shown in FIG. 7, due to the high-frequency current, the skin effect occurs inside the conductor, and the current concentrates at the ends in the width direction of the conductor. In the flat plate-shaped conductors shown in FIGS. 6 and 7, when a high-frequency current flows, the resistance loss per unit mass of the conductor increases.

[0040] For example, by using a flat plate that is as thin and wide as possible, the increase in resistance due to the skin effect is reduced, and the resistance loss per unit mass of the conductor is improved. However, since it is difficult for current to flow near the center in the width direction of the conductor, it is difficult to significantly improve the resistance loss per unit mass of the conductor only by adjusting the width and thickness.

[0041] As shown in FIG. 8, it has also been considered to stack two flat plate-shaped conductors with a gap. In this case, the edges where the current flows can be increased to four sides, and it is possible to somewhat suppress the increase in resistance. However, in the method of stacking conductors, the skin effect also acts in the stacking direction, and it becomes difficult for current to flow through the conductors in the intermediate layers for three or more layers, making it difficult to obtain the effect of reducing resistance.

[0042] As shown in FIG. 9, it has also been considered to cut out the intermediate portion where current hardly flows. In other words, it has also been considered to arrange two sets of two stacked flat plate-shaped conductors side by side in the width direction. In this case, the resistance loss per unit mass of the conductor can be improved compared to the configuration shown in FIG. 8 by the mass of the cut-out intermediate portion.

[0043] Thus, in the method using a flat conductor, as shown in FIG. 9, a structure that improves the resistance loss mass ratio by using a two-layer structure of a flat conductor with a middle portion where current hardly flows removed was considered to be the limit of efficient improvement of resistance loss per mass.

[0044] In addition to this, there is a method of improving the loss at high frequencies by bundling a plurality of conductor plates and applying twisting to give a Litz wire structure, but since it has a complex shape, it is only suitable for mounting on a printed circuit board or the like.

[0045] As shown in FIG. 9, the inventor of the present application found that even when two stacked flat conductors are arranged side by side in the width direction in two sets, current hardly flows at the inner ends in the width direction of a pair of conductors arranged in the width direction. Therefore, the inventor of the present application considered improving the resistance loss per mass by allowing high-frequency current to flow also at the inner ends in the width direction of a pair of conductors arranged in the width direction. As a result of intensive studies, the inventor of the present application found a configuration in which the first conductor portion 11 to the fourth conductor portion 14 bent in a substantially S shape in the width direction are arranged side by side as shown in FIGS. 1 to 4.

[0046] As shown in FIG. 5, in the configuration of the conductor 10 according to the present embodiment, compared with the configuration shown in FIG. 9, current can also flow more easily at the inner ends in the width direction of each of the first conductor portion 11 to the fourth conductor portion 14. The skin effect also occurs in the configuration of the conductor 10 according to the present embodiment, but as shown in FIG. 5, the current density distribution at the center of the conductor (the inner ends in the width direction of each of the first conductor portion 11 to the fourth conductor portion 14) can be improved, and the increase in resistance accompanying the increase in frequency can be improved. Compared with the configuration shown in FIG. 9, the resistance loss per mass can be further improved.

[0047] Also, as described above, in the first portion P1, the outer end portion S11 in the width direction of the first conductor portion 11 is arranged at a position overlapping the third conductor portion 13 in the vertical direction. Thereby, it is possible to make it easier for a high-frequency current to flow to the inner end portion of the third conductor portion 13. This is considered to be because, for example, the third conductor portion 13 is affected by the high-frequency current flowing through the outer end portion S11 of the first conductor portion 11.

[0048] Therefore, by arranging the end portions in the width direction of each of the first conductor portion 11 to the fourth conductor portion 14 as described above, it is possible to make it easier for a high-frequency current to flow to the inner end portions in the width direction of each of the first conductor portion 11 to the fourth conductor portion 14, and to further improve the resistance loss per unit mass.

[0049] FIG. 10 is a graph schematically showing an example of the characteristics of the conductor for high-frequency current according to the embodiment. FIG. 10 schematically shows, as frequency characteristic FC1, an example of the simulation result of the frequency characteristics of the resistance value normalized by the DC resistance value of the conductor 10. Further, in FIG. 10, an example of the simulation result of the frequency characteristics of the resistance value of the flat plate-shaped reference conductor shown in FIGS. 6 and 7 is schematically shown as frequency characteristic FC2.

[0050] As shown in FIG. 10, when compared with the resistance value of the flat plate-shaped reference conductor having a substantially rectangular cross section, in the configuration of the conductor 10 according to the present embodiment, the rate of increase in the resistance value with the increase in frequency is improved. The rate of increase in the resistance value can be further improved, for example, by performing dimensional optimization calculations of the first conductor portion 11 to the fourth conductor portion 14.

[0051] As described above, in the conductor 10 according to the present embodiment, the resistance loss per unit mass can be further reduced. Further, thereby, for example, while suppressing an increase in resistance, the width of the conductor 10 can be narrowed and the conductor 10 can be miniaturized. It becomes possible to apply a conductor 10 having a narrower width while suppressing an increase in resistance. Furthermore, the aspect ratio of the conductor 10 can be improved and the utilization efficiency of the space of the conductor 10 can be enhanced.

[0052] Although some embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0053] 10... conductor, 11... first conductor portion, 12... second conductor portion, 13... third conductor portion, 14... fourth conductor portion, 21, 22... support

Claims

1. a plate-shaped first conductor portion extending in a predetermined direction; a plate-shaped second conductor portion extending in the predetermined direction and arranged side by side with the first conductor portion at an interval in the width direction; a plate-shaped third conductor portion extending in the predetermined direction and arranged above the first conductor portion at an interval in the vertical direction; a plate-shaped fourth conductor portion extending in the predetermined direction, arranged side by side with the third conductor portion at an interval in the width direction, and arranged above the second conductor portion at an interval in the vertical direction; comprising the first conductor portion, the second conductor portion, the third conductor portion, and the fourth conductor portion extend in the predetermined direction and have a bent portion that bends in the width direction; the bending direction of the bent portion of the second conductor portion is opposite to the bending direction of the bent portion of the first conductor portion; the first conductor portion and the second conductor portion have a first portion in which the interval in the width direction between the first conductor portion and the second conductor portion is set to a first interval, and a second portion in which the interval in the width direction between the first conductor portion and the second conductor portion is set to a second interval wider than the first interval; the bending direction of the bent portion of the fourth conductor portion is opposite to the bending direction of the bent portion of the third conductor portion; the third conductor portion and the fourth conductor portion have a third portion in which the interval in the width direction between the third conductor portion and the fourth conductor portion is set to a third interval, and a fourth portion in which the interval in the width direction between the third conductor portion and the fourth conductor portion is set to a fourth interval narrower than the third interval; the third conductor portion and the fourth conductor portion arrange the third portion above the first portion and the fourth portion above the second portion; the third conductor portion intersects the first conductor portion above the first conductor portion; the fourth conductor portion is a conductor for high-frequency current that intersects the second conductor portion above the second conductor portion.

2. In the first portion, the outer end portion of the first conductor portion in the width direction is arranged at a position overlapping the third conductor portion in the vertical direction; In the first portion, the outer end portion of the second conductor portion in the width direction is arranged at a position overlapping the fourth conductor portion in the vertical direction; In the third portion, the inner end portion of the third conductor portion in the width direction is arranged at a position overlapping the first conductor portion in the vertical direction; In the third part, the inner end portion of the fourth conductor portion in the width direction is disposed at a position overlapping the second conductor portion in the vertical direction. In the second part, the inner end portion of the first conductor portion in the width direction is disposed at a position overlapping the third conductor portion in the vertical direction. In the second part, the inner end portion of the second conductor portion in the width direction is disposed at a position overlapping the fourth conductor portion in the vertical direction. In the fourth part, the outer end portion of the third conductor portion in the width direction is disposed at a position overlapping the first conductor portion in the vertical direction. The conductor for high-frequency current according to claim 1, wherein in the fourth part, the outer end portion of the fourth conductor portion in the width direction is disposed at a position overlapping the second conductor portion in the vertical direction. **Claim 3** The conductor for high-frequency current according to claim 1 or 2, wherein the first conductor portion, the second conductor portion, the third conductor portion, and the fourth conductor portion are configured by arranging conductors having the same shape with their orientations switched.

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