Current detection device

Abstract

SOLUTION: Provided is a current detection device including at least two bus bars, each comprising a magnetic detection element, and a first current path whose cross sectional area is large and a second current path whose cross sectional area is small, with the magnetic detection element therebetween, where the at least two bus bars are arranged so that the first current paths face each other. The current detection device may further include other bus bars located between at least the two bus bars and including a magnetic detection element, as well as a third current path whose cross sectional area is large and a fourth current path whose cross sectional area is small, with the magnetic detection element therebetween.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a current detection device. [Background technology]

[0002] Patent Document 1 discloses a "current sensor capable of measuring with high accuracy even if the frequency of the current to be measured changes." Patent Document 2 discloses a "current sensor capable of reducing the influence of adjacent current paths." Patent Document 3 discloses a "current sensor capable of suppressing measurement errors caused by the influence of currents flowing in conductors adjacent to the conductor through which the current to be measured flows, and capable of widening the frequency band of measurable currents." [Prior art document] [Patent documents] [Patent Document 1] JP 2014-055790 A [Patent Document 2] JP 2013-170878 A [Patent Document 3] International Publication No. 2016 / 148022 Summary of the Invention

[0003] A first aspect of the present invention provides a current detection device comprising: a magnetic detection element; and at least two bus bars each including a first current path having a large cross-sectional area and a second current path having a small cross-sectional area, with the magnetic detection element sandwiched therebetween, the at least two bus bars being arranged such that the first current paths face each other.

[0004] The above current detection device may further include another busbar arranged between the at least two busbars and including a magnetic detection element, a third current path having a large cross-sectional area and a fourth current path having a small cross-sectional area sandwiched between the magnetic detection element.

[0005] A second aspect of the present invention provides a current detection device comprising: a magnetic detection element; at least two bus bars each including a first current path having a large cross-sectional area and a second current path having a small cross-sectional area sandwiching the magnetic detection element; and another bus bar disposed between the at least two bus bars and including the magnetic detection element; a third current path having a large cross-sectional area and a fourth current path having a small cross-sectional area sandwiching the magnetic detection element.

[0006] In any of the above current detection devices, the other busbars may be arranged so that a distance between one of the busbars facing the fourth current path of the other busbar is greater than a distance between the other busbar facing the third current path of the other busbar.

[0007] In any of the above current detection devices, the at least two bus bars may be arranged such that the first current paths face each other.

[0008] In any of the above current detection devices, the other busbars may be arranged so that a distance between one of the busbars facing the third current path of the other busbar is greater than a distance between the other busbars facing the fourth current path of the other busbar.

[0009] In any of the above current detection devices, the at least two bus bars may be arranged such that the second current paths face each other.

[0010] In any of the above current detection devices, the first current path and the second current path may have the same thickness but different widths.

[0011] In any of the above current detection devices, the bus bar may include two main bodies to which the first current path and the second current path are connected. In any of the above current detection devices, the first current path and the second current path may be disposed on the inner side of outer edges of the two main bodies in a direction in which the first current path and the second current path are arranged side by side.

[0012] In any of the above current detection devices, each of the two main bodies may have a slit into which a substrate supporting the magnetic detection element is inserted.

[0013] In a third aspect of the present invention, there is provided a current detection device comprising a magnetic detection element and at least two bus bars each including a first current path having a large cross-sectional area and a second current path having a small cross-sectional area, the at least two bus bars being arranged such that the first current paths face each other.

[0014] Any of the above current detection devices may further include another busbar arranged between the at least two busbars and including a magnetic detection element, a third current path having a large cross-sectional area, and a fourth current path having a small cross-sectional area.

[0015] A fourth aspect of the present invention provides a current detection device comprising at least two bus bars each including a magnetic detection element and a first current path having a large cross-sectional area and a second current path having a small cross-sectional area, and further comprising another bus bar disposed between the at least two bus bars and including the magnetic detection element, a third current path having a large cross-sectional area and a fourth current path having a small cross-sectional area.

[0016] In any of the above current detection devices, the other busbars may be arranged so that a distance between one of the busbars facing the fourth current path of the other busbar is greater than a distance between the other busbar facing the third current path of the other busbar.

[0017] In any of the above current detection devices, the at least two bus bars may be arranged such that the first current paths face each other.

[0018] In any of the above current detection devices, the other busbars may be arranged so that a distance between one of the busbars facing the third current path of the other busbar is greater than a distance between the other busbars facing the fourth current path of the other busbar.

[0019] In any of the above current detection devices, the at least two bus bars may be arranged such that the second current paths face each other.

[0020] In any of the above current detection devices, the magnetic detection elements in the at least two bus bars may be arranged so as to overlap the second current path in a top view.

[0021] In any of the above current detection devices, the magnetic detection elements in the at least two bus bars may be arranged so as to overlap a gap between the first current path and the second current path in a top view.

[0022] The above summary of the invention does not list all of the features of the present invention. Also, subcombinations of these features may also be inventions. [Brief description of the drawings]

[0023] [Figure 1] 1 is a perspective view showing an example of a schematic configuration of a current measurement conductor 10 according to a first embodiment. [Diagram 2] 1 is a top view showing an example of a schematic configuration of a current measurement conductor 10 according to a first embodiment. [Diagram 3] 1 is a side view showing an example of a schematic configuration of a current measurement conductor 10 in a first embodiment. [Figure 4] 1 is a top view showing a schematic configuration of a current detection device 101 in a reference example. [Diagram 5] 1 is a top view showing a schematic configuration of a current detection device 102 according to a first embodiment. [Figure 6] 4 is a graph showing the performance of the current detection device 101 of the reference example. [Figure 7] 4 is a graph showing the performance of the current detection device 102 of the first embodiment. [Figure 8] 4 is a graph showing the performance of the current detection device 101 of the reference example. [Figure 9] 4 is a graph showing the performance of the current detection device 102 of the first embodiment. [Figure 10] FIG. 2 is a top view showing a schematic configuration of a current detection device 103 in a comparative example. [Figure 11] 4 is a graph showing the performance of a current detection device 103 of a comparative example. [Figure 12] 4 is a graph showing the performance of a current detection device 103 of a comparative example. [Figure 13] 1 is a graph showing the relationship between the phase difference between alternating currents passed through two current measurement conductors 10 and the error in the detected magnetic flux density in the first embodiment, the comparative example, and the reference example. [Figure 14] FIG. 11 is a diagram showing a current density distribution of a current detection device 103 in a comparative example. [Figure 15] FIG. 11 is a diagram showing a current density distribution of a current detection device 103 in a comparative example. [Figure 16] 4 is a graph showing a range in which the arrangement of the current detection device 102 according to the first embodiment is effective. [Figure 17] 4 is a graph showing a range in which the arrangement of the current detection device 102 according to the first embodiment is effective. [Figure 18] 10 is a top view showing a schematic configuration of a current detection device 104 according to a first example of the second embodiment. FIG. [Figure 19] FIG. 11 is a top view showing a schematic configuration of a current detection device 106 in a second example of the second embodiment. [Figure 20] 10 is a graph showing the performance of a current detection device 104 according to a first example of the second embodiment. [Figure 21]10 is a graph showing the performance of a current detection device 106 according to a second example of the second embodiment. [Figure 22] 13 is a graph comparing performance when distance A and distance B are varied in the second embodiment. [Figure 23] FIG. 11 is a top view showing a schematic configuration of a current detection device 107 in a comparative example of the second embodiment. [Figure 24] 13 is a graph showing the performance of a current detection device 107 as a comparative example of the second embodiment. [Diagram 25] 13 is a graph showing the performance of a current detection device 107 as a comparative example of the second embodiment. [Figure 26] 13 is a graph showing the performance of a current detection device 107 as a comparative example of the second embodiment. [Figure 27] FIG. 13 is a top view showing a schematic configuration of a current detection device 105 according to a first example of the third embodiment. [Figure 28] 11 is a graph comparing the performance of a first example of a current detection device 104 of the second embodiment and a first example of a current detection device 105 of the third embodiment. [Figure 29] 11 is a graph comparing the performance of a first example of a current detection device 104 of the second embodiment and a first example of a current detection device 105 of the third embodiment. [Diagram 30] 11 is a graph comparing the performance of a first example of a current detection device 104 of the second embodiment and a first example of a current detection device 105 of the third embodiment. [Diagram 31] 11 is a graph comparing the performance of a first example of a current detection device 104 of the second embodiment and a first example of a current detection device 105 of the third embodiment. [Diagram 32] FIG. 13 is a top view showing a schematic configuration of a current detection device 108 in a second example of the third embodiment. [Diagram 33] 10 is a top view showing a schematic configuration of a current measurement conductor 10a in another embodiment 1. FIG. [Diagram 34] FIG. 11 is a perspective view showing a schematic configuration of a current measurement conductor 10b in another embodiment 2. [Diagram 35]13 is a top view showing an example of a schematic configuration of a current measurement conductor 10b in another embodiment 2. FIG. [Diagram 36] 11 is a side view showing an example of a schematic configuration of a current measurement conductor 10b in another embodiment 2. FIG. [Figure 37] 13 is a graph comparing the performance of a current detection device 101 of a reference example and a current detection device 102 of the first embodiment when a current measurement conductor 10b of another embodiment is used. [Figure 38] 13 is a graph comparing the performance of a current detection device 101 of a reference example and a current detection device 102 of the first embodiment when a current measurement conductor 10b of another embodiment is used. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0025] [Configuration of the first embodiment] FIG. 1 is a perspective view showing an example of a schematic configuration of a current measurement conductor 10 in the first embodiment. FIG. 2 is a top view showing an example of a schematic configuration of a current measurement conductor 10 in the first embodiment. FIG. 3 is a side view showing an example of a schematic configuration of a current measurement conductor 10 in the first embodiment. An xyz coordinate system is shown in each drawing. As shown in FIG. 1 to FIG. 3, the current measurement conductor 10 has a gap 11, two magnetic detection elements 12, two current paths 13 and 14, and two main bodies 15. The current measurement conductor 10 is also called a bus bar.

[0026] As shown in Figs. 1 to 3, the two current paths 13, 14 are disposed between the two main body portions 15 and extend parallel to each other. A gap 11 is disposed between the two current paths 13, 14. The length of the gap 11 is, for example, 8 mm. A current to be measured flows in the same direction through each of the two current paths 13, 14. In this embodiment, the two current paths 13, 14 are conductors that have a rectangular cross-sectional shape and extend linearly. The cross-sectional shape of the two current paths 13, 14 may be any shape, such as a circle or an ellipse.

[0027] The two current paths 13, 14 have different cross-sectional areas. In the first embodiment, the two current paths 13, 14 have the same thickness but different widths. Here, the width of the current path 13 is smaller than the width of the current path 14. In the first embodiment, the width of the current path 13 in the x direction is 3.5 mm, and the width of the current path 14 in the x direction is 6.5 mm. Thus, the current measurement conductor 10 has an asymmetrical shape with respect to the x direction.

[0028] In the current measurement conductor 10 shown in Figures 1 to 3, two magnetic detection elements 12 are arranged above and below it with a gap 11 between them. The two magnetic detection elements 12 are fixed to the current measurement conductor 10 via a substrate. Arrow A in Figure 2 indicates the range of misalignment of the magnetic detection elements 12 when mounted on the current measurement conductor 10. As shown in Figure 2, the magnetic detection elements 12 may be mounted with a misalignment in the x direction by the width of arrow A.

[0029] The magnetic detection elements 12 detect the strength of the magnetic field generated on each magnetic sensitive surface by the currents to be measured flowing through the two current paths 13, 14, respectively, and output a detection signal according to the detected strength. The magnetic detection elements 12 are arranged so that the magnetic fields generated by the currents to be measured flowing in the same direction through the two current paths 13, 14 penetrate the magnetic sensitive surfaces in opposite directions. In other words, the magnetic detection elements 12 are arranged between the two current paths 13, 14 so that the orientations of the magnetic sensitive surfaces are aligned with each other. In the examples of Figures 1 to 3, the orientation of the magnetic sensitive surfaces, i.e., the normal direction of the surfaces, is the x-direction.

[0030] A magnetoelectric conversion element can be used as the magnetic detection element 12, and as the magnetic detection element, for example, a Hall element that can obtain a detection signal proportional to the magnitude of the magnetic flux density can be used. Note that, in addition to the Hall element, a magnetic resistance element, a magnetic impedance element, etc. may also be used as the magnetic detection element. Furthermore, any element that can uniquely determine a detection signal for an applied magnetic flux density, such as a magnetic sensor IC that combines such a magnetic detection element with an IC processing circuit, can be used as the magnetic detection element 12.

[0031] Fig. 4 is a top view showing a schematic configuration of a current detection device 101 in the reference example. As shown in Fig. 4, the current detection device 101 in the reference example includes two conductors 10 for current measurement. The two conductors 10 for current measurement are arranged side by side in the x direction so that the current paths 13 having smaller widths face each other. If the conductors 10 for current measurement have the same shape, they can also be said to be arranged side by side in the x direction. They are arranged in the same positions in the y and z directions.

[0032] Fig. 5 is a top view showing a schematic configuration of a current detection device 102 in the first embodiment. As shown in Fig. 5, the current detection device 102 in the first embodiment includes two current measurement conductors 10. The two current measurement conductors 10 are arranged side by side in the x direction such that the current paths 14 having larger widths face each other.

[0033] Fig. 6 is a graph showing the performance of the current detection device 101 of the reference example, and Fig. 7 is a graph showing the performance of the current detection device 102 of the first embodiment. Figs. 6 and 7 show the change in magnetic flux density detected by the magnetic detection element 12 depending on the frequency when the phases of the AC currents flowing through the two current measurement conductors 10 are shifted by 180°. Figs. 6 and 7 show the magnetic flux density detected by the magnetic detection element 12 when the position of the magnetic detection element 12 is shifted in the x direction at predetermined intervals along the arrow A in Fig. 2. Note that the same magnitude of AC currents is flowing through the two current measurement conductors 10.

[0034] The vertical axis in Fig. 6 and Fig. 7 indicates the rate of change (%) of magnetic flux density based on a reference frequency of 100 Hz of the AC current flowing through the current measurement conductor 10, and the horizontal axis indicates frequency. Fig. 6 shows the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 on the left side of the current detection device 101 of the reference example, and Fig. 7 shows the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 on the left side of the current detection device 102 of the first embodiment.

[0035] The lines connecting the white circle points in Figures 6 and 7 indicate the case where the distance between the left end of gap 11 and magnetic detection element 12 (meaning the distance from the center of magnetic detection element 12, the same applies below) is 7.2 mm, the lines connecting the square points indicate the case where the distance between the left end of gap 11 and magnetic detection element 12 is 5.2 mm, the lines connecting the triangular points indicate the case where the distance between the left end of gap 11 and magnetic detection element 12 is 4.0 mm, the lines connecting the diamond points indicate the case where the distance between the left end of gap 11 and magnetic detection element 12 is 2.8 mm, and the line connecting the asterisk points indicates the case where the distance between the left end of gap 11 and magnetic detection element 12 is 0.8 mm.

[0036] As shown by the line connecting the open dots in FIG. 6, when the magnetic detection element 12 is disposed near the right end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to increase with an increase in the frequency of the AC current flowing through the current measurement conductor 10. For example, when the frequency is 1000 Hz, the magnetic flux density increases by 20% compared to when the frequency is 100 Hz, and when the frequency is 10000 Hz, the magnetic flux density increases by 18%. On the other hand, as shown by the line connecting the asterisks in FIG. 6, when the magnetic detection element 12 is disposed near the left end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease with an increase in the frequency of the AC current flowing through the current measurement conductor 10. For example, when the frequency is 1000 Hz, the magnetic flux density decreases by 12% compared to when the frequency is 100 Hz, and when the frequency is 10000 Hz, the magnetic flux density decreases by 14%.

[0037] 6, for example, when the frequency is 10,000 Hz, in the current detection device 101 of the reference example, the magnetic flux density detected by the magnetic detection element 12 has an error of 32% between when the magnetic detection element 12 is disposed near the right end of the gap 11 and when the magnetic detection element 12 is disposed near the left end of the gap 11. This indicates that when the mounting position of the magnetic detection element 12 is shifted, the error in the magnetic flux density detected by the magnetic detection element 12 is large. Note that similar large errors occur in other cases, such as when the frequency is 1000 Hz or 100,000 Hz.

[0038] As shown by the line connecting the open dots in FIG. 7, when the magnetic detection element 12 is disposed near the right end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease gradually as the frequency of the AC current flowing through the current measurement conductor 10 increases. For example, when the frequency is 1000 Hz, the magnetic flux density decreases by 5% compared to when the frequency is 100 Hz, and when the frequency is 10000 Hz, the magnetic flux density decreases by 7%. Also, as shown by the line connecting the asterisks in FIG. 7, when the magnetic detection element 12 is disposed near the left end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease even more gradually as the frequency of the AC current flowing through the current measurement conductor 10 increases. For example, when the frequency is 1000 Hz, the magnetic flux density decreases by 2% compared to when the frequency is 100 Hz, and when the frequency is 10000 Hz, the magnetic flux density decreases by 5%.

[0039] 7, for example, when the frequency is 10,000 Hz, in the current detection device 102 of the first embodiment, the magnetic flux density detected by the magnetic detection element 12 has an error of 2% between when the magnetic detection element 12 is disposed near the right end of the gap 11 and when the magnetic detection element 12 is disposed near the left end of the gap 11. This indicates that when the mounting position of the magnetic detection element 12 is shifted, the error in the magnetic flux density detected by the magnetic detection element 12 is small. Note that the error is similarly small in other cases, such as when the frequency is 1000 Hz or 100,000 Hz.

[0040] From the above, it can be seen that when the phases of the AC currents flowing through the two current measurement conductors 10 are shifted by 180°, the current detection device 102 of the first embodiment has a smaller detection error in magnetic flux density due to misalignment of the magnetic detection element 12 than the current detection device 101 of the reference example. Therefore, from the viewpoint of the detection error in magnetic flux density due to misalignment of the magnetic detection element 12, it can be seen that a configuration in which the two current measurement conductors 10 are arranged side by side in the x direction so that the wide current paths 14 face each other is superior.

[0041] Fig. 8 is a graph showing the performance of the current detection device 101 of the reference example, and Fig. 9 is a graph showing the performance of the current detection device 102 of the first embodiment. Fig. 8 and Fig. 9 show the change in magnetic flux density detected by the magnetic detection element 12 depending on the frequency when the phases of the AC currents flowing through the two current measurement conductors 10 are the same. Fig. 8 and Fig. 9 show the magnetic flux density detected by the magnetic detection element 12 when the position of the magnetic detection element 12 is shifted in the x direction at predetermined intervals along the arrow A in Fig. 2.

[0042] The vertical axis in Fig. 8 and Fig. 9 indicates the rate of change (%) of magnetic flux density based on a frequency of 100 Hz of the AC current flowing through the current measurement conductor 10, and the horizontal axis indicates frequency. Fig. 8 shows the magnetic flux density detected by the current measurement conductor 10 on the left side of the current detection device 101 of the reference example, and Fig. 9 shows the magnetic flux density detected by the current measurement conductor 10 on the left side of the current detection device 102 of the first embodiment.

[0043] The line connecting the white circle points in Figures 8 and 9 indicates the case where the distance between the left end of gap 11 and magnetic detection element 12 is 7.2 mm, the line connecting the square points indicates the case where the distance between the left end of gap 11 and magnetic detection element 12 is 5.2 mm, the line connecting the triangular points indicates the case where the distance between the left end of gap 11 and magnetic detection element 12 is 4.0 mm, the line connecting the diamond points indicates the case where the distance between the left end of gap 11 and magnetic detection element 12 is 2.8 mm, and the line connecting the asterisk points indicates the case where the distance between the left end of gap 11 and magnetic detection element 12 is 0.8 mm.

[0044] As shown by the line connecting the open dots in FIG. 8, when the magnetic detection element 12 is disposed near the right end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease gradually as the frequency of the AC current flowing through the current measurement conductor 10 increases. For example, when the frequency is 1000 Hz, the magnetic flux density decreases by 3% compared to when the frequency is 100 Hz, and when the frequency is 10000 Hz, the magnetic flux density decreases by 3%. Also, as shown by the line connecting the asterisks in FIG. 8, when the magnetic detection element 12 is disposed near the left end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease gradually as the frequency of the AC current flowing through the current measurement conductor 10 increases. For example, when the frequency is 1000 Hz, the magnetic flux density decreases by 3% compared to when the frequency is 100 Hz, and when the frequency is 10000 Hz, the magnetic flux density decreases by 3%.

[0045] 8, for example, when the frequency is 10,000 Hz, in the current detection device 101 of the first example, the magnetic flux density detected by the magnetic detection element 12 has an error of 0% width when the magnetic detection element 12 is disposed near the right end of the gap 11 and when the magnetic detection element 12 is disposed near the left end of the gap 11. This indicates that when the mounting position of the magnetic detection element 12 is shifted, the error in the magnetic flux density detected by the magnetic detection element 12 is small. Note that the error is similarly small in other cases, such as when the frequency is 1000 Hz or 100,000 Hz.

[0046] As shown by the line connecting the open dots in FIG. 9, when the magnetic detection element 12 is disposed near the right end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease with an increase in the frequency of the AC current flowing through the current measurement conductor 10. For example, when the frequency is 1000 Hz, the magnetic flux density decreases by 11% compared to when the frequency is 100 Hz, and when the frequency is 10000 Hz, the magnetic flux density decreases by 9%. Also, as shown by the line connecting the asterisks in FIG. 9, when the magnetic detection element 12 is disposed near the left end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to increase with an increase in the frequency of the AC current flowing through the current measurement conductor 10. For example, when the frequency is 1000 Hz, the magnetic flux density increases by 20% compared to when the frequency is 100 Hz, and when the frequency is 10000 Hz, the magnetic flux density increases by 22%.

[0047] 9, for example, when the frequency is 10,000 Hz, in the current detection device 102 of the first embodiment, the magnetic flux density detected by the magnetic detection element 12 has an error of 31% between when the magnetic detection element 12 is disposed near the right end of the gap 11 and when the magnetic detection element 12 is disposed near the left end of the gap 11. This indicates that when the mounting position of the magnetic detection element 12 is shifted, the error in the magnetic flux density detected by the magnetic detection element 12 is large. Note that similar large errors occur in other cases, such as when the frequency is 1000 Hz or 100,000 Hz.

[0048] It can be seen that when the phases of the AC currents flowing through the two current measurement conductors 10 are the same, the current detection device 101 of the reference example has a smaller detection error in magnetic flux density due to misalignment of the magnetic detection elements 12 than the current detection device 102 of the first embodiment. Therefore, when the phases of the AC currents flowing through the two current measurement conductors 10 are the same, from the viewpoint of the detection error in magnetic flux density due to misalignment of the magnetic detection elements 12, the two current measurement conductors 10 may be arranged side by side in the x direction so that the current paths 13 with narrower widths face each other.

[0049] Fig. 10 is a top view showing a schematic configuration of a current detection device 103 in a comparative example. As shown in Fig. 10, the current detection device 103 in the comparative example includes two conductors 10 for current measurement. The current detection device 103 in the comparative example is configured by arranging two conductors 10 for current measurement shown in Fig. 1 in the same direction. That is, two conductors 10 for current measurement are arranged in the same manner, with the narrower current path 13 of the conductor 10 on the right side and the wider current path 14 on the left side, so that the narrower current path 13 and the wider current path 14 face each other.

[0050] Fig. 11 and Fig. 12 are graphs showing the performance of the current detection device 103 of the comparative example. Fig. 11 and Fig. 12 show the change in magnetic flux density detected by the magnetic detection element 12 depending on the frequency when the phases of the AC currents flowing through the two current measurement conductors 10 are shifted by 180°. Fig. 11 and Fig. 12 show the magnetic flux density detected by the magnetic detection element 12 when the position of the magnetic detection element 12 is shifted in the x direction at a predetermined interval along the arrow A in Fig. 2.

[0051] 11 and 12, the vertical axis represents the rate of change (%) of magnetic flux density based on a frequency of 100 Hz of the AC current flowing through current measurement conductor 10, and the horizontal axis represents frequency. Fig. 11 shows the magnetic flux density detected by magnetic detection element 12 of current measurement conductor 10 on the left side of current detection device 103 of the comparative example, and Fig. 12 shows the magnetic flux density detected by magnetic detection element 12 of current measurement conductor 10 on the right side of current detection device 103 of the comparative example.

[0052] The line connecting the white circle points in Figures 11 and 12 indicates the case where the distance between the left end of gap 11 and magnetic detection element 12 is 7.2 mm, the line connecting the square points indicates the case where the distance between the left end of gap 11 and magnetic detection element 12 is 5.2 mm, the line connecting the triangular points indicates the case where the distance between the left end of gap 11 and magnetic detection element 12 is 4.0 mm, the line connecting the diamond points indicates the case where the distance between the left end of gap 11 and magnetic detection element 12 is 2.8 mm, and the line connecting the asterisk points indicates the case where the distance between the left end of gap 11 and magnetic detection element 12 is 0.8 mm.

[0053] 11 and 12, in the current detection device 103 of the comparative example, the error in the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 on the left side is large, and the error in the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 on the right side is small. Therefore, when the current measurement conductors 10 are lined up in the same orientation, it can be seen that there is variation between those with large errors and those with small errors.

[0054] FIG. 13 is a graph showing the relationship between the phase difference of the AC current flowing through the two current measurement conductors 10 and the error of the detected magnetic flux density in the first embodiment, the reference example, and the comparative example. In FIG. 13, the dashed line connected by square points shows the graph of the current detection device 102 of the first embodiment, and the solid line connected by white circles shows the graph of the current detection device 101 of the reference example. In FIG. 13, the dashed line connected by triangular points shows the graph of the left current measurement conductor 10 in the current detection device 103 of the comparative example, and the solid line connected by asterisk points shows the graph of the right current measurement conductor 10 in the current detection device 103 of the comparative example. The vertical axis of FIG. 13 shows the error of the magnetic flux density detected by the arrangement of the magnetic detection element 12 when the frequency of the AC current is 2000 Hz. The horizontal axis of FIG. 13 shows the phase difference of the AC current flowing through the two current measurement conductors 10.

[0055] From the above, by selecting the arrangement of the reference example or the arrangement of the first embodiment for the two current measurement conductors 10 depending on the phase of the AC current, it is possible to reduce the detection error of the magnetic flux density due to the positional misalignment of the magnetic detection element 12 compared to the arrangement of the comparative example.

[0056] 13, when the phase difference between the AC currents flowing through the two current measurement conductors 10 is in the range of 0 to 80°, the current detection device 101 of the reference example has a smaller error in magnetic flux density detected due to the arrangement of the magnetic detection elements 12 than the current detection device 103 of the comparative example, so the current detection device 101 of the reference example in which the current paths 13 with narrow widths face each other may be used. On the other hand, it can be seen that when the phase difference between the AC currents flowing through the two current measurement conductors 10 is in the range of 100 to 180°, the current detection device 102 of the first embodiment has a smaller error in magnetic flux density detected due to the arrangement of the magnetic detection elements 12 than the current detection device 103 of the comparative example.

[0057] The reason why the magnitude of the error in the magnetic flux density detected by the arrangement of the magnetic detection elements 12 changes depending on the phase difference of the AC currents flowing through the two current measurement conductors 10 as shown in FIG. 13 is explained by the distribution of the current density of the current measurement conductors 10, which will be described below. FIGS. 14 and 15 are diagrams showing the distribution of the current density of the current detection device 103 in the comparative example. In FIGS. 14 and 15, the current density is indicated by hatching in the narrow current path 13 and the wide current path 14. The hatching is thick in the areas with high current density, and thin in the areas with low current density. FIG. 14 shows a case where the phases of the AC currents flowing through the two current measurement conductors 10 are shifted by 180°, and FIG. 15 shows a case where the phases of the AC currents flowing through the two current measurement conductors 10 are the same.

[0058] As shown in FIG. 14, when the phases are shifted by 180°, the current density of the current path closer to the other current measurement conductor 10 is higher. That is, in the left current measurement conductor 10, the current is concentrated on the right side of the current path 13 with a smaller width on the right side, and in the right current measurement conductor 10, the current is concentrated on the left side of the current path 14 with a larger width on the left side. This is because an eddy current is generated in the other current measurement conductor 10 by a magnetic flux created by a current flowing in one current measurement conductor 10. For example, when a current flows in the +y direction (toward the back of the paper) in the left current measurement conductor 10, a current flows in the -y direction (toward the front of the paper) in the right current measurement conductor 10, and an eddy current in the +y direction is generated in the left current measurement conductor 10, particularly near the narrow current path 13, by a magnetic flux created by the current flowing in the right current measurement conductor 10. This causes a high current density on the right side of the narrow current path 13 on the right side.

[0059] On the other hand, as shown in FIG. 15, when the phases are the same, the current density of the current path farther from the other current measurement conductor 10 is higher. That is, in the left current measurement conductor 10, the current is concentrated on the left side of the current path 14 that is wider on the left side, and in the right current measurement conductor 10, the current is concentrated on the right side of the current path 13 that is narrower on the right side. This is because an eddy current is generated in the other current measurement conductor 10 by a magnetic flux created by a current flowing in one current measurement conductor 10. For example, when a current flows in the +y direction (into the depth of the paper) in the left current measurement conductor 10, a current flows in the +y direction (into the depth of the paper) in the right current measurement conductor 10, and an eddy current in the -y direction is generated in the left current measurement conductor 10, particularly near the narrow current path 13, by a magnetic flux created by a current flowing in the right current measurement conductor 10. As a result, in the current path 13 with the narrower width of the left current measurement conductor 10, the current flowing through itself is cancelled out by the eddy current coming from the other side, resulting in a higher current density on the left side of the current path 14 with the wider width on the left side. In this way, when the current density of the current path on either the left or right side of the other current measurement conductor 10 becomes higher due to the influence of the other current measurement conductor 10, by arranging the current measurement conductor 10 in a direction in which the current density of the wider current path 14 becomes higher, the error in the magnetic flux density detected by the magnetic detection element 12 can be reduced. As described above, which of the current paths on the left or right side of the current measurement conductor 10 has a higher current density depends on the phase difference with the current flowing through the other current measurement conductor 10, so that whether the current detection device 101 of the reference example or the current detection device 102 of the first embodiment should be adopted also depends on the phase difference with the current flowing through the other current measurement conductor 10.

[0060] 14 and 15, when using two asymmetric current measurement conductors 10 having a narrow current path 13 and a wide current path 14, bias in current density occurs due to the phase difference between the currents flowing through the left and right current measurement conductors 10. When the phases are shifted by 180°, the current concentrates in the inner current path, and when the phases are the same, the current concentrates in the outer current path.

[0061] Fig. 16 is a graph showing the range where the arrangement of the current detection device 102 of the first embodiment is effective. In Fig. 16, square points indicate the error of the magnetic flux density detected by the current measurement conductor 10 on the left side of the current detection device 101 of the reference example, white circle points indicate the error of the magnetic flux density detected by the current measurement conductor 10 on the left side of the current detection device 102 of the first embodiment, triangular points indicate the error of the magnetic flux density detected by the current measurement conductor 10 on the right side of the current detection device 103 of the comparative example, asterisk points indicate the error of the magnetic flux density detected by the current measurement conductor 10 on the left side of the current detection device 103 of the comparative example, and dashed lines indicate the error of the magnetic flux density detected by the current measurement conductor 10 of the single-phase current detection device. The vertical axis in Fig. 16 indicates the maximum value of the error of the magnetic flux density detected by the arrangement of the magnetic detection elements 12, and the horizontal axis indicates the distance (mm) between the left and right current measurement conductors 10. FIG. 16 shows an example in which the frequency of the AC currents flowing through the two current measurement conductors 10 is 2000 Hz and the phases are shifted by 180°.

[0062] As shown in FIG. 16, when the distance between the left and right current measurement conductors 10 is within 10 mm, the error in the magnetic flux density of the current detection device 101 of the reference example is large, whereas the error in the magnetic flux density of the current detection device 102 of the first embodiment is small, and the difference between the errors in the magnetic flux density of the two is large. However, the difference between the two becomes smaller as the distance between the left and right current measurement conductors 10 is increased. When the distance between the left and right current measurement conductors 10 approaches 100 mm, the error in the magnetic flux density of the current detection device 101 of the reference example and the error in the magnetic flux density of the current detection device 102 of the first embodiment both approach that of a single phase, and when the distance between the left and right current measurement conductors 10 exceeds 100 mm, the difference between the two becomes almost zero. This is because the more one current measurement conductor 10 is separated from the other current measurement conductor 10, the smaller the influence of the eddy current from the other current measurement conductor 10.

[0063] Therefore, as described above, when the phases of the AC currents flowing through the two current measurement conductors 10 are shifted by 180°, the current detection device 102 of the first embodiment can reduce the detection error of the magnetic flux density due to the positional deviation of the magnetic detection element 12 more than the current detection device 103 of the comparative example. Also, when the phases of the AC currents flowing through the two current measurement conductors 10 are shifted by 180°, the current detection device 102 of the first embodiment can reduce the detection error of the magnetic flux density due to the positional deviation of the magnetic detection element 12 more than the current detection device 101 of the reference example. However, it can be seen that the effect of reducing the detection error by the above arrangement becomes weaker as the distance between the current measurement conductors 10 increases.

[0064] As shown in FIG. 16, when the phases of the AC currents flowing through the two current measurement conductors 10 are shifted by 180°, the magnetic flux density error detected by the magnetic detection element 12 of the current measurement conductor 10 on the right side of the current detection device 103 of the comparative example is close to the value of the magnetic flux density error detected by the left current measurement conductor 10 of the current detection device 102 of the first embodiment, and the magnetic flux density error detected by the magnetic detection element 12 of the left current measurement conductor 10 of the current detection device 103 of the comparative example is close to the value of the magnetic flux density error detected by the left current measurement conductor 10 of the current detection device 101 of the reference example.

[0065] Fig. 17 is a graph showing the range where the arrangement of the current detection device 102 of the first embodiment is effective. In Fig. 17, the white circle points indicate the error of the magnetic flux density detected by the current measurement conductor 10 on the left side of the current detection device 101 of the reference example, the square points indicate the error of the magnetic flux density detected by the current measurement conductor 10 on the left side of the current detection device 102 of the first embodiment, the triangular points indicate the error of the magnetic flux density detected by the current measurement conductor 10 on the right side of the current detection device 103 of the comparative example, the asterisk points indicate the error of the magnetic flux density detected by the current measurement conductor 10 on the left side of the current detection device 103 of the comparative example, and the dashed line indicates the error of the magnetic flux density detected by the current measurement conductor 10 of the single-phase current detection device. In Fig. 17, the vertical axis indicates the maximum value of the error of the magnetic flux density detected by the arrangement of the magnetic detection element 12, and the horizontal axis indicates the distance (mm) between the left and right current measurement conductors 10. FIG. 17 shows an example in which the frequency of the AC currents flowing through the two current measurement conductors 10 is 2000 Hz and the phases are shifted by 120°.

[0066] 17, even when the phases of the AC currents flowing through the two current measurement conductors 10 are shifted by 120°, as in the case where the phases are shifted by 180°, the current detection device 102 of the first embodiment can reduce detection errors in magnetic flux density caused by misalignment of the magnetic detection element 12 more than the current detection device 103 of the comparative example. Also, when the phases of the AC currents flowing through the two current measurement conductors 10 are shifted by 120°, the current detection device 102 of the first embodiment can reduce detection errors in magnetic flux density caused by misalignment of the magnetic detection element 12 more than the current detection device 101 of the reference example.

[0067] [Advantages of the First Embodiment] According to the current detection device of the first embodiment, when the phase of the AC current flowing through the two current measurement conductors 10 is shifted by 100° to 180°, the current paths 14 with larger widths are arranged side by side in the x direction facing each other, which reduces the error in the magnetic flux density detected by the magnetic detection element 12 when the mounting position of the magnetic detection element 12 is shifted, and prevents a decrease in performance due to a shift in the mounting position of the magnetic detection element 12.

[0068] [First Example of the Second Embodiment] Fig. 18 is a top view showing a schematic configuration of a current detection device 104 in a first example of the second embodiment. As shown in Fig. 18, the current detection device 104 includes three current measurement conductors 10. Of the three current measurement conductors 10, the two current measurement conductors 10 arranged on the outside are arranged side by side in the x direction so that the current paths 14 with larger widths face each other. Of the three current measurement conductors 10, the two current measurement conductors 10 arranged in the center are arranged so that the current path 14 with larger widths is on the right side. The current measurement conductors 10 are arranged so that the distance A between the left current measurement conductor 10 and the center current measurement conductor 10 is the same as the distance B between the center current measurement conductor 10 and the right current measurement conductor 10 (A = B).

[0069] [Second Example of Second Embodiment] FIG. 19 is a top view showing a schematic configuration of a current detection device 106 in a second example of the second embodiment. As shown in FIG. 19, the current detection device 106 includes three current measurement conductors 10. The two current measurement conductors 10 arranged on the outside of the three current measurement conductors 10 are arranged side by side in the x direction so that the current paths 14 with larger widths face each other. The current measurement conductor 10 arranged in the center of the three current measurement conductors 10 is arranged so that the current path 14 with larger width is on the right side. The current measurement conductor 10 is arranged so that the distance A between the left current measurement conductor 10 and the center current measurement conductor 10 is larger than the distance B between the center current measurement conductor 10 and the right current measurement conductor 10. In this example, the three current measurement conductors 10 correspond to the U phase, V phase, and W phase of a three-phase AC current, respectively, and the AC currents flowing through the three current measurement conductors 10 may be configured to have phases that differ from each other by 120°. In FIG. 19, the current measurement conductor 10 on the left side may correspond to the U phase, the current measurement conductor 10 in the center may correspond to the V phase, and the current measurement conductor 10 on the right side may correspond to the W phase.

[0070] Fig. 20 is a graph showing the performance of a current detection device 104 of a first example of the second embodiment, and Fig. 21 is a graph showing the performance of a current detection device 106 of a second example of the second embodiment. Figs. 20 and 21 compare the performance at distances A and B. Fig. 20 shows a graph of the rate of change, depending on frequency, of the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 of the V-phase of the current detection device 104 of the first example, and Fig. 21 shows a graph of the rate of change, depending on frequency, of the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 of the V-phase of the current detection device 106 of the second example.

[0071] 20 and 21, the error in the magnetic flux density detected by the magnetic detection element 12 is smaller in the case of Fig. 21 than in Fig. 20. Therefore, it can be seen that the error in the magnetic flux density detected by the magnetic detection element 12 is smaller when distance A>distance B than when distance A=distance B.

[0072] Fig. 22 is a graph comparing the performance when the distance A and the distance B are varied in the second embodiment. The horizontal axis of Fig. 22 indicates the movement distance of the central V-phase current measurement conductor 10 from an equally spaced point (i.e., A=B) in the current detection device of the second embodiment. When the V-phase current measurement conductor 10 is moved closer to the current measurement conductor 10 on the left, the movement distance becomes negative, and when the V-phase current measurement conductor 10 is moved closer to the current measurement conductor 10 on the right, the movement distance becomes positive. The vertical axis of Fig. 22 indicates the error in the magnetic flux density detected by the magnetic detection element 12 of the U-phase current measurement conductor 10.

[0073] The line connecting the square points in Figure 22 indicates the case where the AC frequency is 10,000 Hz, the line connecting the white circle points indicates the case where the AC frequency is 5,000 Hz, the line connecting the asterisk points indicates the case where the AC frequency is 2,000 Hz, and the line connecting the triangular points indicates the case where the AC frequency is 1,000 Hz.

[0074] 22, it can be seen that the closer the V-phase current measurement conductor 10 is to the W-phase current measurement conductor 10 on the right side, the smaller the error in the magnetic flux density detected by the magnetic detection element 12 of the U-phase current measurement conductor 10. Therefore, the current detection device 106 of the second example is more preferable than the current detection device 104 of the first example in terms of the arrangement of the V-phase current measurement conductor 10.

[0075] FIG. 23 is a top view showing a schematic configuration of a current detection device 107 in a comparative example of the second embodiment. As shown in FIG. 23, the current detection device 107 in the comparative example includes three current measurement conductors 10. In each of the three current measurement conductors 10, the narrow current path 13 is arranged on the left side, and the wide current path 14 is arranged on the right side. That is, the three current measurement conductors 10 are arranged to face in the same direction. The distance A between the left current measurement conductor 10 and the central current measurement conductor 10 is the same as the distance B between the central current measurement conductor 10 and the right current measurement conductor 10 (A=B). The three current measurement conductors 10 correspond to the U phase, V phase, and W phase of a three-phase AC current, respectively, and the AC currents flowing through the three current measurement conductors 10 are configured to have phases that differ from each other by 120°.

[0076] Fig. 24 to Fig. 26 are graphs showing the performance of the comparative current detection device 107. Fig. 24 shows the rate of change with frequency of the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 on the left side of the comparative current detection device 107, Fig. 25 shows the rate of change with frequency of the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 in the center of the comparative current detection device 107, and Fig. 26 shows the rate of change with frequency of the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 on the right side of the comparative current detection device 107.

[0077] 24 to 26, the vertical axis represents the rate of change (%) of magnetic flux density based on a frequency of 100 Hz of the AC current flowing through the current measurement conductor 10, and the horizontal axis represents frequency. Figures 24 to 26 show the rate of change of magnetic flux density detected by the magnetic detection element 12 when the position of the magnetic detection element 12 is shifted in the x direction at specified intervals along the arrow A in Figure 2.

[0078] The lines connecting the white circle points in Figures 24 to 26 indicate the case where the distance between the left end of gap 11 and the magnetic detection element 12 is 7.2 mm, the lines connecting the square points indicate the case where the distance between the left end of gap 11 and the magnetic detection element 12 is 5.2 mm, the lines connecting the triangular points indicate the case where the distance between the left end of gap 11 and the magnetic detection element 12 is 4.0 mm, the lines connecting the diamond points indicate the case where the distance between the left end of gap 11 and the magnetic detection element 12 is 2.8 mm, and the lines connecting the asterisk points indicate the case where the distance between the left end of gap 11 and the magnetic detection element 12 is 0.8 mm.

[0079] As shown in Figures 24 to 26, the detection error of the magnetic flux density of the magnetic detection element 12 of the current measurement conductor 10 on the left side of the current detection device 107 of the comparative example is small, but the detection errors of the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 in the center and the magnetic detection element 12 of the current measurement conductor 10 on the right side are large values.

[0080] [Effects of the second embodiment] According to the first example current detection device 104 of the second embodiment, the current detection device 104 includes three current measurement conductors 10, and of the three current measurement conductors 10, the two current measurement conductors 10 arranged on the outside are arranged side by side in the x direction so that the current paths 14 having larger widths face each other. This makes it possible to reduce an error in the magnetic flux density detected by the magnetic detection element 12 when the mounting position of the magnetic detection element 12 is shifted, and to prevent a decrease in performance due to a position shift of the magnetic detection element 12 when mounted.

[0081] According to the second example current detection device 106 of the second embodiment, the current detection device 106 includes three current measurement conductors 10, and the central V-phase current measurement conductor 10 is disposed close to the W-phase current measurement conductor 10 on the right side. This makes it possible to reduce an error in the magnetic flux density detected by the magnetic detection element 12 when the mounting position of the magnetic detection element 12 is shifted, and prevents a decrease in performance due to a misalignment of the magnetic detection element 12 during mounting.

[0082] [First Example of the Third Embodiment] FIG. 27 is a top view showing a schematic configuration of a current detection device 105 in a first example of the third embodiment. As shown in FIG. 27, the current detection device 105 in the first example of the third embodiment includes three current measurement conductors 10. Of the three current measurement conductors 10, the two current measurement conductors 10 arranged on the outside are arranged side by side in the x direction so that the current paths 13 with smaller widths face each other. Of the three current measurement conductors 10, the two current measurement conductors 10 arranged in the center are arranged so that the current path 14 with larger widths is on the right side. The current measurement conductors 10 are arranged so that the distance A between the left current measurement conductor 10 and the center current measurement conductor 10 is the same as the distance B between the center current measurement conductor 10 and the right current measurement conductor 10 (A=B).

[0083] Figures 28 to 31 are graphs comparing the performance of a first example of a current detection device 104 of the second embodiment and a first example of a current detection device 105 of the third embodiment when the phases of the AC currents flowing through the three current measurement conductors 10 are configured to differ by 120° each. Figure 28 shows the rate of change with frequency of the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 on the left side of the current detection device 104 in the first example of the second embodiment, Figure 29 shows the rate of change with frequency of the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 on the right side of the current detection device 104 in the first example of the second embodiment, Figure 30 shows the rate of change with frequency of the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 on the left side of the current detection device 105 in the first example of the third embodiment, and Figure 31 shows the rate of change with frequency of the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 on the right side of the current detection device 105 in the first example of the third embodiment.

[0084] 28 to 31, the vertical axis represents the rate of change (%) of magnetic flux density based on a frequency of 100 Hz of the AC current flowing through the current measurement conductor 10, and the horizontal axis represents frequency. Figures 28 to 31 show the rate of change of magnetic flux density detected by magnetic detection element 12 when the position of magnetic detection element 12 is shifted in the x direction at specified intervals along arrow A in Figure 2.

[0085] The lines connecting the white circle points in Figures 28 to 31 indicate the case where the distance between the left end of gap 11 and the magnetic detection element 12 is 7.2 mm, the lines connecting the square points indicate the case where the distance between the left end of gap 11 and the magnetic detection element 12 is 5.2 mm, the lines connecting the triangular points indicate the case where the distance between the left end of gap 11 and the magnetic detection element 12 is 4.0 mm, the lines connecting the diamond points indicate the case where the distance between the left end of gap 11 and the magnetic detection element 12 is 2.8 mm, and the lines connecting the asterisk points indicate the case where the distance between the left end of gap 11 and the magnetic detection element 12 is 0.8 mm.

[0086] 28, in the current measurement conductor 10 on the left side of the current detection device 104 of the first example of the second embodiment, when the magnetic detection element 12 is disposed near the right end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease gently according to the frequency of the AC current flowing through the current measurement conductor 10. Similarly, when the magnetic detection element 12 is disposed near the left end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease even more gently according to the frequency of the AC current flowing through the current measurement conductor 10.

[0087] 29, in the current measurement conductor 10 on the right side of the current detection device 104 of the first example of the second embodiment, when the magnetic detection element 12 is disposed near the right end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease gently according to the frequency of the AC current flowing through the current measurement conductor 10. Similarly, when the magnetic detection element 12 is disposed near the left end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease gently according to the frequency of the AC current flowing through the current measurement conductor 10.

[0088] 30 , in the current measurement conductor 10 on the left side of the current detection device 105 of the first example of the third embodiment, when the magnetic detection element 12 is disposed near the right end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to increase in the range of +15% to +20% depending on the frequency of the AC current flowing through the current measurement conductor 10. On the other hand, when the magnetic detection element 12 is disposed near the left end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease in the range of -10% to -15% depending on the frequency of the AC current flowing through the current measurement conductor 10.

[0089] 31 , in the current measurement conductor 10 on the right side of the current detection device 105 of the first example of the third embodiment, when the magnetic detection element 12 is disposed near the right end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease in the range of −10% to −15% depending on the frequency of the AC current flowing through the current measurement conductor 10. On the other hand, when the magnetic detection element 12 is disposed near the left end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to increase in the range of +15% to +20% depending on the frequency of the AC current flowing through the current measurement conductor 10.

[0090] 28 and 29, in the current detection device 104 of the first example of the second embodiment, the margin of error in the magnetic flux density detected by the magnetic detection element 12 is small between when the magnetic detection element 12 is disposed near the right end of the gap 11 and when the magnetic detection element 12 is disposed near the left end of the gap 11. This indicates that when the mounting position of the magnetic detection element 12 is shifted, the error in the magnetic flux density detected by the magnetic detection element 12 is small.

[0091] 30 and 31, in the current detection device 105 of the first example of the third embodiment, the error range of the magnetic flux density detected by the magnetic detection element 12 is large between when the magnetic detection element 12 is disposed in a position close to the right end of the gap 11 and when the magnetic detection element 12 is disposed in a position close to the left end of the gap 11. This indicates that when the mounting position of the magnetic detection element 12 is shifted, the error of the magnetic flux density detected by the magnetic detection element 12 is large.

[0092] From the above, it can be seen that when the phases of the AC currents flowing through the three current measurement conductors 10 differ by 120°, the current detection device 104 of the first example of the second embodiment has a smaller detection error in magnetic flux density due to misalignment of the magnetic detection element 12 than the current detection device 105 of the first example of the third embodiment. Therefore, from the viewpoint of detection error in magnetic flux density due to misalignment of the magnetic detection element 12, it can be seen that the configuration of the current detection device 104 of the first example of the second embodiment in which the two outermost current measurement conductors 10 of the three current measurement conductors 10 are arranged side by side in the x direction so that the current paths 14 with larger widths face each other is superior.

[0093] In the first example of the second embodiment, when the phase difference of the AC current between adjacent current measurement conductors 10 is close to 120°, it is preferable to arrange the current measurement conductors 10 so that the distance A between the left current measurement conductor 10 and the central current measurement conductor 10 is greater than the distance B between the central current measurement conductor 10 and the right current measurement conductor 10. This is presumably because, when focusing on the central current measurement conductor 10 and the right current measurement conductor 10, the same effect as in the first embodiment is obtained. Therefore, the arrangement of the second embodiment is preferably used when the phase difference of the AC current between adjacent current measurement conductors 10 is 120°.

[0094] Therefore, in the first example of the second embodiment, the three current measurement conductors 10 correspond to the U phase, V phase, and W phase, respectively, of a three-phase AC current, and the AC currents flowing through the three current measurement conductors 10 may be configured to have phases differing by 120° from each other.

[0095] On the other hand, in the first example of the third embodiment, when the phase of the AC current between adjacent current measurement conductors 10 is in the range of 0° to 80°, it is preferable that the distance A between the left current measurement conductor 10 and the central current measurement conductor 10 is smaller than the distance B between the central current measurement conductor 10 and the right current measurement conductor 10. This can be presumed to be due to the fact that, when focusing on the central current measurement conductor 10 and the left current measurement conductor 10, an effect similar to that of the reference example is produced.

[0096] Therefore, in the first example of the third embodiment, it is preferable to use a current measurement conductor 10 with a phase difference of AC current between adjacent current measurement conductors 10 in the range of 0° to 80°.

[0097] Furthermore, the arrangements of the second and third embodiments are not limited to the case where three current measurement conductors 10 are arranged, i.e., the case of three-phase AC using three current measurement conductors 10, but may be applied to any three adjacent current measurement conductors 10 when four or more current measurement conductors 10 are arranged.

[0098] [Second Example of the Third Embodiment] Fig. 32 is a top view showing a schematic configuration of a current detection device 108 in a second example of the third embodiment. As shown in Fig. 32, the current detection device 108 includes three current measurement conductors 10. Of the three current measurement conductors 10, the two current measurement conductors 10 arranged on the outside are arranged side by side in the x direction such that the current paths 13 with smaller widths face each other. Of the three current measurement conductors 10, the current measurement conductor 10 arranged in the center is arranged such that the current path 13 with smaller width is on the left side. The current measurement conductors 10 are arranged such that the distance A between the left current measurement conductor 10 and the center current measurement conductor 10 is smaller than the distance B between the center current measurement conductor 10 and the right current measurement conductor 10.

[0099] [Effects of the third embodiment] 27, the current detection device 105 of the first example of the third embodiment includes three current measurement conductors 10, and the two current measurement conductors 10 arranged on the outside of the three current measurement conductors 10 are arranged side by side in the x direction so that the current paths 13 with smaller widths face each other. In this way, when the phase difference of the AC current between adjacent current measurement conductors 10 is in the range of 0 to 80°, it is possible to reduce the error in the magnetic flux density detected by the magnetic detection element 12 when the mounting position of the magnetic detection element 12 is shifted, and it is possible to prevent a decrease in performance due to a misalignment of the mounting position of the magnetic detection element 12.

[0100] 32, the current detection device 108 includes three current measurement conductors 10, and the central V-phase current measurement conductor 10 is disposed close to the U-phase current measurement conductor 10 on the left side. In this way, when the phase difference of the AC current between adjacent current measurement conductors 10 is in the range of 0 to 80°, it is possible to reduce the error in the magnetic flux density detected by the magnetic detection element 12 when the mounting position of the magnetic detection element 12 is shifted, and it is possible to prevent a decrease in performance due to a misalignment of the mounting position of the magnetic detection element 12.

[0101] [Another embodiment 1] FIG. 33 is a top view showing a schematic configuration of the conductor for current measurement 10a in another embodiment 1. The conductor for current measurement 10a in another embodiment 1 has a gap 11, a magnetic detection element 12, a current path 13 with a small width, a current path 14 with a large width, two main parts 15, and a slit 16. The magnetic detection element 12 is fixed to and supported by a substrate. The substrate is inserted into the slit 16 and fixed to the conductor for current measurement 10a. The two current paths 13 and 14 are each disposed inside the outer edges of the two main parts 15 in the direction in which the two current paths 13 and 14 are arranged side by side. The conductor for current measurement 10a in another embodiment 1 may be used instead of the conductor for current measurement 10 in the first embodiment.

[0102] [Another embodiment 2] FIG. 34 is a perspective view showing a schematic configuration of the current measurement conductor 10b in another embodiment 2. FIG. 35 is a top view showing an example of a schematic configuration of the current measurement conductor 10b in another embodiment 2. FIG. 36 is a side view showing an example of a schematic configuration of the current measurement conductor 10b in another embodiment 2. In the first embodiment, the magnetic detection element 12 is disposed inside the gap 11 in the top view as shown in FIG. 2. However, the magnetic detection element 12 may be disposed above or below the current path 13 having a small width. As shown in FIGS. 34 to 36, in the current measurement conductor 10b in another embodiment 2, the magnetic detection element 12 is disposed above the current path 13 having a small width. The arrow L shown in FIG. 35 indicates the range of misalignment of the magnetic detection element 12 in the current measurement conductor 10b in mounting. As shown in FIG. 35, the magnetic detection element 12 may be mounted in a state where it is misaligned by the width of the arrow L in the x direction. Thus, in a current measurement conductor 10, etc., the magnetic detection element 12 may be arranged so as to overlap with the current path 13 which is narrower in top view, or so as to overlap with the current path 14 which is wider in top view, or so as to overlap with the gap 11 between the current path 14 which is wider and the current path 13 which is narrower in top view, or so as to be arranged to the side of the current path 14 which is wider in top view, or so as to be arranged to the side of the current path 13 which is narrower in top view.

[0103] 37 and 38 are graphs comparing the performance of the current detection device 101 of the first example and the current detection device 102 of the second example when the current measurement conductor 10b of the second alternative embodiment is used. Fig. 37 and Fig. 38 show the change in magnetic flux density detected by the magnetic detection element 12 depending on the frequency when the phases of the AC currents flowing through the two current measurement conductors 10b are shifted by 180°. Fig. 37 and Fig. 38 show the magnetic flux density detected by the magnetic detection element 12 when the position of the magnetic detection element 12 is shifted in the x direction at a predetermined interval along the arrow L in Fig. 35.

[0104] The vertical axis of Fig. 37 and Fig. 38 shows the rate of change (%) of magnetic flux density based on a reference frequency of 100 Hz of the AC current flowing through the current measurement conductor 10b, and the horizontal axis shows frequency. Fig. 37 shows the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 on the left side of the current detection device 101 of the first example, and Fig. 38 shows the magnetic flux density detected by the magnetic detection element 12 of the current measurement conductor 10 on the left side of the current detection device 102 of the second example.

[0105] In Figures 37 and 38, the line connecting the x points indicates the case where the distance between the left end of the current path 13 and the magnetic detection element 12 is 3.5 mm, the line connecting the white circle points indicates the case where the distance between the left end of the current path 13 and the magnetic detection element 12 is 2.8 mm, the line connecting the square points indicates the case where the distance between the left end of the current path 13 and the magnetic detection element 12 is 2.1 mm, the line connecting the triangular points indicates the case where the distance between the left end of the current path 13 and the magnetic detection element 12 is 1.4 mm, the line connecting the diamond points indicates the case where the distance between the left end of the current path 13 and the magnetic detection element 12 is 0.7 mm, and the line connecting the asterisk points indicates the case where the distance between the left end of the current path 13 and the magnetic detection element 12 is 0 mm.

[0106] 37, in the current detection device 101 of the first example, the error range of the magnetic flux density detected by the magnetic detection element 12 is large between when the magnetic detection element 12 is arranged in a position close to the right end of the current path 13 and when the magnetic detection element 12 is arranged in a position close to the left end of the current path 13. This indicates that when the mounting position of the magnetic detection element 12 is shifted, the error of the magnetic flux density detected by the magnetic detection element 12 is large.

[0107] 38, in the current detection device 102 of the second example, the margin of error in the magnetic flux density detected by the magnetic detection element 12 is small between when the magnetic detection element 12 is disposed near the right end of the gap 11 and when the magnetic detection element 12 is disposed near the left end of the gap 11. This indicates that when the mounting position of the magnetic detection element 12 is shifted, the error in the magnetic flux density detected by the magnetic detection element 12 is small.

[0108] As described above, even when the current measurement conductor 10b in the second embodiment is used instead of the current measurement conductor 10 in the first embodiment, when the phases of the AC currents flowing through the two current measurement conductors 10 are shifted by 180°, it is found that the detection error of the magnetic flux density due to the positional deviation of the magnetic detection element 12 is smaller when the current detection device 102 in the second example in which the current paths 14 with larger widths are arranged side by side in the x direction so as to face each other is employed. Therefore, it is found that the same rule as in the first embodiment applies.

[0109] [Other embodiment 3] In the first and second embodiments, the two current paths 13 and 14 have the same thickness and different widths. However, the two current paths 13 and 14 may have different cross-sectional areas, for example, the same width and different thicknesses. In this case, the thickness of the current path 14 may be thicker than the thickness of the current path 13. In addition, the two current paths 13 and 14 may have different widths and thicknesses. In this case, the width of the current path 14 may be larger than the width of the current path 13, and the thickness of the current path 14 may be thicker than the thickness of the current path 13. In the first and second embodiments, the two or three current measurement conductors 10 have the same shape. However, different shapes may be adopted. In the other embodiments described above, each of the current measurement conductors 10a, etc. has been described as having one magnetic detection element 12, but instead, the current measurement conductors 10a, etc. may have two or more magnetic detection elements 12 arranged in the x-axis direction.

[0110] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications and improvements can also be included in the technical scope of the present invention.

[0111] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and may be realized in any order unless the output of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is explained using "first," "next," etc. for convenience, it does not mean that it is essential to perform the process in this order. [Explanation of symbols]

[0112] 10, 10a, 10b Current measurement conductor 11 Gap 12 Magnetic sensing element 13 Current Path 14 Current Path 15 Main body 16 Slit 101~108 Current detection device

Claims

1. a magnetic detection element; and at least two bus bars each including a first current path having a large cross-sectional area and a second current path having a small cross-sectional area, the first current path sandwiching the magnetic detection element; The at least two bus bars are arranged so that the first current paths face each other. Current detection device.

2. the at least two bus bars are disposed between the bus bars, and the bus bar includes a magnetic detection element, and a third current path having a large cross-sectional area and a fourth current path having a small cross-sectional area sandwiching the magnetic detection element. The current detection device according to claim 1 .

3. a magnetic detection element; and at least two bus bars each including a first current path having a large cross-sectional area and a second current path having a small cross-sectional area, the first current path sandwiching the magnetic detection element; the at least two bus bars are disposed between the bus bars, and the bus bar includes a magnetic detection element, and a third current path having a large cross-sectional area and a fourth current path having a small cross-sectional area sandwiching the magnetic detection element. Current detection device.

4. the other busbars are arranged such that a distance between the fourth current path of the other busbar and one of the busbars facing the fourth current path is greater than a distance between the third current path of the other busbar and the other of the busbars facing the third current path of the other busbar. The current detection device according to claim 3 .

5. The at least two bus bars are arranged so that the first current paths face each other. The current detection device according to claim 4.

6. the other busbars are arranged such that a distance between one of the busbars facing the third current path of the other busbars is greater than a distance between the other of the busbars facing the fourth current path of the other busbars. The current detection device according to claim 3 .

7. The at least two bus bars are arranged so that the second current paths face each other. The current detection device according to claim 6.

8. 8. The current sensing device of claim 1, wherein the first current path and the second current path have the same thickness and different widths.

9. the bus bar includes two main body portions to which the first current path and the second current path are connected, the first current path and the second current path are each disposed on the inner side of outer edges of the two main body portions in a direction in which the first current path and the second current path are arranged side by side; A current detection device according to any one of claims 1 to 7.

10. Each of the two main bodies has a slit into which a substrate supporting the magnetic detection element is inserted. The current detection device according to claim 9.

11. At least two bus bars each including a magnetic detection element and a first current path having a large cross-sectional area and a second current path having a small cross-sectional area; The at least two bus bars are arranged so that the first current paths face each other. Current detection device.

12. and further comprising: another bus bar disposed between the at least two bus bars and including a magnetic detection element, a third current path having a large cross-sectional area, and a fourth current path having a small cross-sectional area. The current detection device according to claim 11.

13. At least two bus bars each including a magnetic detection element and a first current path having a large cross-sectional area and a second current path having a small cross-sectional area; and further comprising: another bus bar disposed between the at least two bus bars and including a magnetic detection element, a third current path having a large cross-sectional area, and a fourth current path having a small cross-sectional area. Current detection device.

14. the other busbars are arranged such that a distance between the fourth current path of the other busbar and one of the busbars facing the fourth current path is greater than a distance between the third current path of the other busbar and the other of the busbars facing the third current path of the other busbar. The current detection device according to claim 13.

15. The at least two bus bars are arranged so that the first current paths face each other.

15. A current detection device according to claim 14.

16. the other busbars are arranged such that a distance between one of the busbars facing the third current path of the other busbars is greater than a distance between the other of the busbars facing the fourth current path of the other busbars. The current detection device according to claim 13.

17. The at least two bus bars are arranged so that the second current paths face each other.

17. A current sensing device according to claim 16.

18. In the at least two bus bars, the magnetic detection elements are arranged so as to overlap with the second current paths in a top view. A current detection device according to any one of claims 11 to 17.

19. In the at least two bus bars, the magnetic detection elements are arranged so as to overlap with a gap between the first current path and the second current path in a top view. A current detection device according to any one of claims 11 to 17.

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