Current detection device

Abstract

A current detection device is provided. The current detection device is provided with at least two bus bars, each bus bar is provided with 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 which sandwich the magnetic detection element, and the at least two bus bars are arranged such that the first current paths face each other. Further, another bus bar disposed between the at least two bus bars may be provided, and the other bus bar is provided with 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 that sandwich the magnetic detection element.

Description

Technical Field

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

[0002] Patent Document 1 discloses a "current sensor capable of performing high-precision measurements even when the frequency of the current being measured varies." Patent Document 2 discloses a "current sensor capable of minimizing the influence of adjacent current paths." Patent Document 3 discloses a "current sensor capable of suppressing measurement errors caused by the influence of current flowing through other conductors adjacent to the conductor through which the current being measured flows, and capable of expanding the frequency band of the current that can be measured."

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-055790

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2013-170878

[0007] Patent Document 3: International Publication No. 2016 / 148022 Summary of the Invention

[0008] A first aspect of the present invention provides a current detection device. The current detection device includes at least two bus bars, each of the bus bars including a magnetic detection element, a first current path with a large cross-sectional area, and a second current path with a small cross-sectional area sandwiching the magnetic detection element. The at least two bus bars are arranged such that the first current paths face each other.

[0009] The current detection device may further include another bus bar arranged between the at least two bus bars, the other bus bar including a magnetic detection element, and a third current path with a large cross-sectional area and a fourth current path with a small cross-sectional area sandwiching the magnetic detection element.

[0010] A second aspect of the present invention provides a current detection device. The current detection device includes at least two bus bars, each bus bar including a magnetic detection element, a first current path with a large cross-sectional area, and a second current path with a small cross-sectional area sandwiching the magnetic detection element, and further including another bus bar disposed between the at least two bus bars, the other bus bar including the magnetic detection element, a third current path with a large cross-sectional area, and a fourth current path with a small cross-sectional area sandwiching the magnetic detection element.

[0011] It can also be that in any of the above-mentioned current detection devices, the other bus bar is configured in such a manner that the distance between the other bus bar and the bus bar on the side facing the fourth current path of the other bus bar is greater than the distance between the other bus bar and the bus bar on the other side facing the third current path of the other bus bar.

[0012] In any of the above-described current detection devices, the at least two bus bars may be arranged so that the first current paths face each other.

[0013] It can also be that in any of the above-mentioned current detection devices, the other bus bar is configured in such a manner that the distance between the other bus bar and the bus bar on the side facing the third current path of the other bus bar is greater than the distance between the other bus bar and the bus bar on the other side facing the fourth current path of the other bus bar.

[0014] In any of the above-described current detection devices, the at least two bus bars may be arranged so that the second current paths face each other.

[0015] Alternatively, in any of the above-mentioned current detection devices, the first current path and the second current path may have the same thickness and different widths.

[0016] Alternatively, in any of the above-described current detection devices, the busbar may include two main bodies connected to the first current path and the second current path. Alternatively, in any of the above-described current detection devices, the first current path and the second current path may be respectively arranged inward of outer edges of the two main bodies in the direction in which the first current path and the second current path are arranged.

[0017] In any of the above-described current detection devices, each of the two main body portions may include a slit into which a substrate supporting the magnetic detection element is inserted.

[0018] A third aspect of the present invention provides a current detection device including at least two bus bars each having a magnetic detection element, a first current path having a large cross-sectional area, and a second current path having a small cross-sectional area, wherein the at least two bus bars are arranged such that the first current paths face each other.

[0019] Any of the above current detection devices may further include another bus bar disposed between the at least two bus bars, the other bus bar 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.

[0020] A fourth aspect of the present invention provides a current detection device. The current detection device includes at least two bus bars, each bus bar including a magnetic detection element, a first current path having a large cross-sectional area, and a second current path having a small cross-sectional area, and further includes another bus bar disposed between the at least two bus bars, the other bus bar 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.

[0021] It can also be that in any of the above-mentioned current detection devices, the other bus bar is configured in such a manner that the distance between the other bus bar and the bus bar on the side facing the fourth current path of the other bus bar is greater than the distance between the other bus bar and the bus bar on the other side facing the third current path of the other bus bar.

[0022] In any of the above-described current detection devices, the at least two bus bars may be arranged so that the first current paths face each other.

[0023] It can also be that in any of the above-mentioned current detection devices, the other bus bar is configured in such a manner that the distance between the other bus bar and the bus bar on the side facing the third current path of the other bus bar is greater than the distance between the other bus bar and the bus bar on the other side facing the fourth current path of the other bus bar.

[0024] In any of the above-described current detection devices, the at least two bus bars may be arranged so that the second current paths face each other.

[0025] In any of the above-described current detection devices, the magnetic detection element may be arranged in the at least two bus bars so as to overlap with the second current path in a plan view.

[0026] In any of the above-described current detection devices, the magnetic detection elements may be arranged in the at least two bus bars so as to overlap with a gap between the first current path and the second current path in a plan view.

[0027] The above summary of the invention does not list all the features of the present invention, and subcombinations of these feature groups may also constitute inventions. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a perspective view showing an example of a schematic structure of the current measuring conductor 10 in the first embodiment.

[0029] Figure 2 It is a plan view showing an example of the schematic structure of the current measuring conductor 10 in the first embodiment.

[0030] Figure 3 This is a side view showing an example of the schematic structure of the current measuring conductor 10 in the first embodiment.

[0031] Figure 4 1 is a plan view showing a schematic configuration of a current detection device 101 in a reference example.

[0032] Figure 5 It is a plan view showing a schematic configuration of the current detection device 102 in the first embodiment.

[0033] Figure 6 Graphs showing the performance of the current detection device 101 of the reference example.

[0034] Figure 7 Graphs showing the performance of the current detection device 102 according to the first embodiment.

[0035] Figure 8 Graphs showing the performance of the current detection device 101 of the reference example.

[0036] Figure 9 Graphs showing the performance of the current detection device 102 according to the first embodiment.

[0037] Figure 10 1 is a plan view showing a schematic configuration of a current detection device 103 in a comparative example.

[0038] Figure 11 Graphs showing the performance of the current detection device 103 of the comparative example.

[0039] Figure 12 Graphs showing the performance of the current detection device 103 of the comparative example.

[0040] Figure 13 Graphs showing the relationship between the phase difference between the alternating currents flowing through the two current-measuring conductors 10 and the error in the detected magnetic flux density in the first embodiment, the comparative example, and the reference example.

[0041] Figure 14 1 is a diagram showing the distribution of current density of the current detection device 103 in the comparative example.

[0042] Figure 15 1 is a diagram showing the distribution of current density of the current detection device 103 in the comparative example.

[0043] Figure 16 This is a graph showing the range in which the arrangement configuration of the current detection device 102 according to the first embodiment is effective.

[0044] Figure 17This is a graph showing the range in which the arrangement configuration of the current detection device 102 according to the first embodiment is effective.

[0045] Figure 18 It is a plan view showing a schematic configuration of a current detection device 104 in the first example of the second embodiment.

[0046] Figure 19 It is a plan view showing a schematic configuration of a current detection device 106 in a second example of the second embodiment.

[0047] Figure 20 Graphs showing the performance of the current detection device 104 according to the first example of the second embodiment.

[0048] Figure 21 Graphs showing the performance of the current detection device 106 according to the second example of the second embodiment.

[0049] Figure 22 This is a graph comparing the performance when the distance A and the distance B are varied in the second embodiment.

[0050] Figure 23 It is a plan view showing a schematic configuration of a current detection device 107 in a comparative example of the second embodiment.

[0051] Figure 24 Graphs showing the performance of the current detection device 107 according to a comparative example of the second embodiment.

[0052] Figure 25 Graphs showing the performance of the current detection device 107 according to a comparative example of the second embodiment.

[0053] Figure 26 Graphs showing the performance of the current detection device 107 according to a comparative example of the second embodiment.

[0054] Figure 27 It is a plan view showing a schematic configuration of a current detection device 105 in the first example of the third embodiment.

[0055] Figure 28 This is a graph comparing the performance of the current detection device 104 according to the first example of the second embodiment and the current detection device 105 according to the first example of the third embodiment.

[0056] Figure 29 This is a graph comparing the performance of the current detection device 104 according to the first example of the second embodiment and the current detection device 105 according to the first example of the third embodiment.

[0057] Figure 30This is a graph comparing the performance of the current detection device 104 according to the first example of the second embodiment and the current detection device 105 according to the first example of the third embodiment.

[0058] Figure 31 This is a graph comparing the performance of the current detection device 104 according to the first example of the second embodiment and the current detection device 105 according to the first example of the third embodiment.

[0059] Figure 32 It is a plan view showing a schematic configuration of a current detection device 108 in a second example of the third embodiment.

[0060] Figure 33 This is a plan view showing a schematic structure of a current measuring conductor 10a in another first embodiment.

[0061] Figure 34 This is a perspective view showing a schematic structure of a current measuring conductor 10b in another second embodiment.

[0062] Figure 35 This is a plan view showing an example of a schematic structure of a current measuring conductor 10b in another second embodiment.

[0063] Figure 36 This is a side view showing an example of the schematic structure of the current measuring conductor 10b in another second embodiment.

[0064] Figure 37 This is a graph comparing the performance of the current detection device 101 of the reference example and the current detection device 102 of the first embodiment when using the current measuring conductor 10 b of the second embodiment.

[0065] Figure 38 This is a graph comparing the performance of the current detection device 101 of the reference example and the current detection device 102 of the first embodiment when using the current measuring conductor 10 b of the second embodiment. DETAILED DESCRIPTION

[0066] The present invention will be described below by way of embodiments of the invention, but the following embodiments are not intended to limit the invention as defined in the claims. Furthermore, not all combinations of features described in the embodiments are necessarily essential to the solution provided by the invention.

[0067] [Structure of the first embodiment]

[0068] Figure 1 It is a perspective view showing an example of a schematic structure of the current measuring conductor 10 in the first embodiment. Figure 2It is a plan view showing an example of the schematic structure of the current measuring conductor 10 in the first embodiment. Figure 3 1 is a side view showing an example of the schematic structure of the current measuring conductor 10 in the first embodiment. In each figure, an xyz coordinate system is shown. Figures 1 to 3 As shown, the current measuring conductor 10 includes a gap 11, two magnetic detection elements 12, two current paths 13 and 14, and two main body portions 15. The current measuring conductor 10 is also called a bus bar.

[0069] like Figures 1 to 3 As shown, two current paths 13 and 14 are arranged between two main bodies 15 and extend parallel to each other. A gap 11 is provided between the two current paths 13 and 14. The length of gap 11 is, for example, 8 mm. The measured current flows in the same direction in each of the two current paths 13 and 14. In this embodiment, the two current paths 13 and 14 are conductors having a rectangular cross-section and extending in a straight line. Furthermore, the cross-sectional shape of the two current paths 13 and 14 can be any other shape, such as a circle or an ellipse.

[0070] The two current paths 13 and 14 have different cross-sectional areas. In the first embodiment, the two current paths 13 and 14 have the same thickness but different widths. Here, the width of current path 13 is smaller than that of current path 14. In the first embodiment, the width of current path 13 in the x-direction is 3.5 mm, and the width of current path 14 in the x-direction is 6.5 mm. Thus, the current measuring conductor 10 has a non-lineasymmetric shape in the x-direction.

[0071] exist Figures 1 to 3 In the illustrated current measuring conductor 10, two magnetic detection elements 12 are arranged above and below the gap 11 with a gap 11 interposed therebetween. The two magnetic detection elements 12 are fixed to the current measuring conductor 10 via a substrate. Figure 2 The arrow A shown in FIG. 1 indicates the range of positional deviation of the magnetic detection element 12 when it is mounted on the current measuring conductor 10. Figure 2 As shown, the magnetic detection element 12 may be mounted in a state where the position thereof is shifted by the width of the arrow A in the x direction.

[0072] The magnetic detection element 12 detects the strength of the magnetic field generated on each magnetically sensitive surface due to the measured current flowing through the two current paths 13 and 14, and outputs a detection signal corresponding to the detected strength. The magnetic detection element 12 is configured so that the magnetic field generated by the measured current flowing in the same direction in the two current paths 13 and 14 passes through the magnetically sensitive surface in opposite directions. In other words, the magnetic detection element 12 is configured so that the directions of the magnetically sensitive surfaces are aligned between the two current paths 13 and 14. Figures 1 to 3 In the example of , the orientation of the magnetically sensitive surface, that is, the normal direction of the surface is the x direction.

[0073] As the magnetic detection element 12, a magnetoelectric conversion element can be used. For example, a Hall element that can generate a detection signal proportional to the magnitude of the magnetic flux density can be used as the magnetoelectric conversion element. In addition to Hall elements, magnetoresistive elements, magnetoimpedance elements, and the like can also be used as magnetoelectric conversion elements. Furthermore, if a structure such as a magnetic sensor IC that combines these magnetoelectric conversion elements with an IC processing circuit and that uniquely determines the detection signal for the applied magnetic flux density is used, it can be used as the magnetic detection element 12.

[0074] Figure 4 1 is a top view showing the schematic structure of the current detection device 101 in the reference example. Figure 4 As shown, a current detection device 101 of the reference example includes two current measuring conductors 10. The two current measuring conductors 10 are arranged side by side in the x-direction, with narrow current paths 13 facing each other. If the current measuring conductors 10 have the same shape, they can be said to be arranged side by side in the x-direction. They are arranged in alignment in the y- and z-directions.

[0075] Figure 5 1 is a top view showing the schematic structure of the current detection device 102 in the first embodiment. Figure 5 As shown in FIG. 1 , the current detection device 102 of the first embodiment includes two current measuring conductors 10. The two current measuring conductors 10 are arranged side by side in the x direction so that the wide current paths 14 thereof face each other.

[0076] Figure 6 is a graph showing the performance of the current detection device 101 of the reference example, Figure 7 Graphs showing the performance of the current detection device 102 according to the first embodiment. Figure 6 and Figure 7 FIG. 1 shows a change in the magnetic flux density detected by the magnetic detection element 12 with respect to frequency when the phases of the alternating currents flowing through the two current-measuring conductors 10 differ by 180°. Figure 6 and Figure 7 The magnetic detection element 12 is positioned along Figure 2 The arrow A in FIG. 1 shows the magnetic flux density detected by the magnetic detection element 12 when the magnetic detection element 12 is shifted in the x direction by a predetermined interval.

[0077] Figure 6 and Figure 7The vertical axis shows the rate of change (%) of magnetic flux density based on a frequency of 100 Hz of the alternating current flowing through the current-measuring conductor 10 , and the horizontal axis shows the frequency. Figure 6 FIG. 2 shows the magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 on the left side of the current detection device 101 of the reference example. Figure 7 The magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 on the left side of the current detection device 102 according to the first embodiment is shown.

[0078] Figure 6 and Figure 7 The line connecting the points of the white circle shows that the distance between the left end of the gap 11 and the magnetic detection element 12 (referring to the distance from the center of the magnetic detection element 12, the same below) is 7.2 mm, the line connecting the points of the quadrilateral shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 5.2 mm, the line connecting the points of the triangle shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 4.0 mm, the line connecting the points of the diamond shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 2.8 mm, and the line connecting the points of the asterisk shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 0.8 mm.

[0079] like Figure 6 As shown by the line connecting the white circled points, when the magnetic detection element 12 is positioned near the right end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to increase as the frequency of the AC current flowing through the current measuring conductor 10 increases. For example, at a frequency of 1000 Hz, the magnetic flux density increases by 20% compared to a frequency of 100 Hz, and at a frequency of 10,000 Hz, the magnetic flux density increases by 18%. On the other hand, Figure 6 As shown by the line connecting the points marked with asterisks, when magnetic detection element 12 is positioned near the left end of gap 11, the magnetic flux density detected by magnetic detection element 12 tends to decrease as the frequency of the alternating current flowing through current measuring conductor 10 increases. For example, at a frequency of 1000 Hz, the magnetic flux density decreases by 12% compared to a frequency of 100 Hz, and at a frequency of 10,000 Hz, the magnetic flux density decreases by 14%.

[0080] like Figure 6As shown, for example, at a frequency of 10,000 Hz, in reference example current detection device 101, there is a 32% difference in the magnetic flux density detected by magnetic detection element 12 between when magnetic detection element 12 is positioned near the right end of gap 11 and when magnetic detection element 12 is positioned near the left end of gap 11. This indicates that the error in the magnetic flux density detected by magnetic detection element 12 is large when the mounting position of magnetic detection element 12 is offset. Similarly, large errors occur in other cases, such as those at frequencies of 1,000 Hz and 100,000 Hz.

[0081] like Figure 7 As shown by the line connecting the white circle points, when the magnetic detection element 12 is located 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 measuring conductor 10 increases. For example, at a frequency of 1000 Hz, the magnetic flux density decreases by 5% compared to a frequency of 100 Hz, and at a frequency of 10000 Hz, the magnetic flux density decreases by 7%. In addition, as Figure 7 As shown by the line connecting the points marked with asterisks, when magnetic detection element 12 is positioned near the left end of gap 11, the magnetic flux density detected by magnetic detection element 12 tends to decrease gradually as the frequency of the alternating current flowing through current measuring conductor 10 increases. For example, at a frequency of 1000 Hz, the magnetic flux density decreases by 2% compared to a frequency of 100 Hz, and at a frequency of 10,000 Hz, the magnetic flux density decreases by 5%.

[0082] like Figure 7 As shown, for example, at a frequency of 10,000 Hz, in current detection device 102 of the first embodiment, there is a 2% error in the magnetic flux density detected by magnetic detection element 12 between when magnetic detection element 12 is positioned near the right end of gap 11 and when magnetic detection element 12 is positioned near the left end of gap 11. This indicates that the error in the magnetic flux density detected by magnetic detection element 12 is small even when the mounting position of magnetic detection element 12 is offset. The same small error is also observed in other cases, such as those at frequencies of 1,000 Hz and 100,000 Hz.

[0083] As can be seen from the above, when the phases of the alternating currents flowing through the two current-measuring conductors 10 differ by 180°, the current detection device 102 of the first embodiment exhibits a smaller error in magnetic flux density detection due to positional deviation of the magnetic detection element 12 than the current detection device 101 of the reference example. Therefore, from the perspective of magnetic flux density detection error due to positional deviation of the magnetic detection element 12, it is clear that a configuration in which the two current-measuring conductors 10 are arranged in the x-direction with their wide current paths 14 facing each other is superior.

[0084] Figure 8 is a graph showing the performance of the current detection device 101 of the reference example, Figure 9 Graphs showing the performance of the current detection device 102 according to the first embodiment. Figure 8 and Figure 9 FIG. 1 shows a change in magnetic flux density detected by the magnetic detection element 12 due to frequency when the phases of the alternating currents flowing through the two current-measuring conductors 10 are the same. Figure 8 and Figure 9 The magnetic detection element 12 is positioned along Figure 2 The arrow A in FIG. 1 indicates the magnetic flux density detected by the magnetic detection element 12 when the magnetic detection element 12 is shifted by a predetermined interval in the x direction.

[0085] Figure 8 and Figure 9 The vertical axis shows the rate of change (%) of magnetic flux density based on a frequency of 100 Hz of the alternating current flowing through the current-measuring conductor 10 , and the horizontal axis shows the frequency. Figure 8 FIG. 2 shows the magnetic flux density detected by the current measuring conductor 10 on the left side of the current detection device 101 of the reference example. Figure 9 The magnetic flux density detected by the current measuring conductor 10 on the left side of the current detection device 102 according to the first embodiment is shown.

[0086] Figure 8 and Figure 9 The line connecting the points of the white circles shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 7.2 mm, the line connecting the points of the quadrilateral shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 5.2 mm, the line connecting the points of the triangle shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 4.0 mm, the line connecting the points of the diamond shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 2.8 mm, and the line connecting the points of the asterisk shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 0.8 mm.

[0087] like Figure 8As shown by the line connecting the white circled points, when the magnetic detection element 12 is positioned 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 alternating current flowing through the current measuring conductor 10 increases. For example, at a frequency of 1000 Hz, the magnetic flux density decreases by 3% compared to a frequency of 100 Hz, and at a frequency of 10,000 Hz, the magnetic flux density decreases by 3%. In addition, as Figure 8 As shown by the line connecting the points marked with asterisks, when magnetic detection element 12 is positioned near the left end of gap 11, the magnetic flux density detected by magnetic detection element 12 tends to gradually decrease as the frequency of the alternating current flowing through current measuring conductor 10 increases. For example, at a frequency of 1000 Hz, the magnetic flux density decreases by 3% compared to a frequency of 100 Hz, and at a frequency of 10,000 Hz, the magnetic flux density decreases by 3%.

[0088] like Figure 8 As shown, for example, at a frequency of 10,000 Hz, in reference example current detection device 101, there is a 0% error in the magnetic flux density detected by magnetic detection element 12 between when magnetic detection element 12 is positioned near the right end of gap 11 and when magnetic detection element 12 is positioned near the left end of gap 11. This indicates that the error in the magnetic flux density detected by magnetic detection element 12 is small even when the mounting position of magnetic detection element 12 is offset. The same small error is also observed in other cases, such as those at frequencies of 1,000 Hz and 100,000 Hz.

[0089] like Figure 9 As shown by the line connecting the white circled points, when the magnetic detection element 12 is positioned near the right end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease as the frequency of the AC current flowing through the current measuring conductor 10 increases. For example, at a frequency of 1000 Hz, the magnetic flux density decreases by 11% compared to a frequency of 100 Hz, and at a frequency of 10,000 Hz, the magnetic flux density decreases by 9%. In addition, as Figure 9 As shown by the line connecting the points marked with asterisks, when magnetic detection element 12 is positioned near the left end of gap 11, the magnetic flux density detected by magnetic detection element 12 tends to increase with the frequency of the alternating current flowing through current measuring conductor 10. For example, at a frequency of 1000 Hz, the magnetic flux density increases by 20% compared to a frequency of 100 Hz, and at a frequency of 10,000 Hz, the magnetic flux density increases by 22%.

[0090] like Figure 9 As shown, for example, at a frequency of 10,000 Hz, in current detection device 102 of the first embodiment, there is a 31% difference in the magnetic flux density detected by magnetic detection element 12 between when magnetic detection element 12 is positioned near the right end of gap 11 and when magnetic detection element 12 is positioned near the left end of gap 11. This indicates that the error in the magnetic flux density detected by magnetic detection element 12 is large when the mounting position of magnetic detection element 12 is offset. Similarly, large errors occur in other cases, such as those at frequencies of 1,000 Hz and 100,000 Hz.

[0091] It can be seen that when the phases of the AC currents flowing through the two current-measuring conductors 10 are the same, the current detection device 101 of the reference example has a smaller detection error in the magnetic flux density due to positional offset of the magnetic detection element 12 than the current detection device 102 of the first embodiment. Therefore, when the phases of the AC currents flowing through the two current-measuring conductors 10 are the same, from the perspective of reducing the detection error in the magnetic flux density due to positional offset of the magnetic detection element 12, the two current-measuring conductors 10 can be arranged side by side in the x-direction with their narrow current paths 13 facing each other.

[0092] Figure 10 1 is a top view showing the schematic structure of the current detection device 103 in the comparative example. Figure 10 As shown in FIG. 1 , the current detection device 103 of the comparative example includes two current measuring conductors 10. Figure 1 The structure shown has two current measuring conductors 10 arranged in the same direction. That is, the current measuring conductors 10 are arranged in the same manner, with the smaller current path 13 being on the right side and the larger current path 14 being on the left side. Therefore, the smaller current path 13 and the larger current path 14 are arranged so as to face each other.

[0093] Figure 11 and Figure 12 Graphs showing the performance of the current detection device 103 of the comparative example. Figure 11 and Figure 12 FIG. 1 shows a change in the magnetic flux density detected by the magnetic detection element 12 with respect to frequency when the phases of the alternating currents flowing through the two current-measuring conductors 10 differ by 180°. Figure 11 and Figure 12 The magnetic detection element 12 is positioned along Figure 2 Magnetic flux density detected by the magnetic detection element 12 when the arrows A in FIG. 5 are shifted at predetermined intervals in the x direction.

[0094] Figure 11 and Figure 12 The vertical axis shows the rate of change (%) of magnetic flux density based on a frequency of 100 Hz of the alternating current flowing through the current-measuring conductor 10 , and the horizontal axis shows the frequency. Figure 11 FIG. 2 shows the magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 on the left side of the current detection device 103 of the comparative example. Figure 12 The magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 on the right side of the current detection device 103 of the comparative example is shown.

[0095] Figure 11 and Figure 12 The line connecting the points of the white circles shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 7.2 mm, the line connecting the points of the quadrilateral shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 5.2 mm, the line connecting the points of the triangle shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 4.0 mm, the line connecting the points of the diamond shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 2.8 mm, and the line connecting the points of the asterisk shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 0.8 mm.

[0096] like Figure 11 and Figure 12 As shown, 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 measuring conductor 10 on the left side is large, while the error in the magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 on the right side is small. Therefore, it can be seen that when the current measuring conductors 10 are arranged in the same orientation, there is a deviation between the current measuring conductors 10 with large errors and the current measuring conductors 10 with small errors.

[0097] Figure 13 Graph showing the relationship between the phase difference of the alternating current flowing through the two current measuring conductors 10 and the error in the detected magnetic flux density in the first embodiment, the reference example, and the comparative example. Figure 13 In FIG, a dotted line connecting the points of the squares shows a graph of the current detection device 102 of the first embodiment, and a solid line connecting the points of the white circles shows a graph of the current detection device 101 of the reference example. Figure 13 In FIG. 1 , a dotted line connected by triangular points shows a graph of the current measuring conductor 10 on the left side of the current detection device 103 of the comparative example, and a solid line connected by asterisk points shows a graph of the current measuring conductor 10 on the right side of the current detection device 103 of the comparative example. Figure 13The vertical axis shows the error in the detected magnetic flux density caused by the arrangement of the magnetic detection element 12 when the frequency of the alternating current is 2000 Hz. Figure 13 The horizontal axis of represents the phase difference between the alternating currents flowing through the two current measuring conductors 10 .

[0098] As described above, for the two current measuring conductors 10, by selecting the configuration of the reference example or the configuration of the first embodiment according to the phase of the AC current, the detection error of the magnetic flux density caused by the positional deviation of the magnetic detection element 12 can be reduced compared with the configuration of the comparative example.

[0099] like Figure 13 As shown, when the phase difference between the AC currents flowing through the two current-measuring conductors 10 is within the range of 0° to 80°, the error in the detected magnetic flux density of the current detection device 101 of the reference example due to the arrangement of the magnetic detection elements 12 is smaller than that of the current detection device 103 of the comparative example. Therefore, the current detection device 101 of the reference example, in which the current paths 13 of narrow width face each other, can be used. On the other hand, it can be seen that when the phase difference between the AC currents flowing through the two current-measuring conductors 10 is within the range of 100° to 180°, the error in the detected magnetic flux density of the current detection device 102 of the first embodiment due to the arrangement of the magnetic detection elements 12 is smaller than that of the current detection device 103 of the comparative example.

[0100] The following describes the distribution of the current density of the current measuring conductor 10. Figure 13 The reason why the magnitude of the error in the detected magnetic flux density varies due to the arrangement of the magnetic detection element 12 is that the phase difference between the alternating currents flowing through the two current measuring conductors 10 is different as shown. Figure 14 and Figure 15 : is a graph showing the distribution of current density of the current detection device 103 in the comparative example. Figure 14 and Figure 15 In FIG. 1 , the current density is shown by shading in the narrow current path 13 and the wide current path 14. The portion with high current density has dark shading, and the portion with low current density has light shading. Figure 14 The figure shows a case where the phases of the alternating currents flowing through the two current measuring conductors 10 differ by 180°. Figure 15 The case where the phases of the alternating currents flowing through the two current-measuring conductors 10 are the same is shown.

[0101] like Figure 14As shown, when the phase difference is 180°, the current density in the current path closer to the other current measuring conductor 10 becomes higher. Specifically, in the left current measuring conductor 10, the current concentrates on the right side of the narrow current path 13 on the right, while in the right current measuring conductor 10, the current concentrates on the left side of the wide current path 14 on the left. This is because the magnetic flux generated by the current flowing through one current measuring conductor 10 generates eddy currents in the other current measuring conductor 10. For example, if current flows in the +y direction (inward on the page) through the left current measuring conductor 10 and current flows in the -y direction (frontward on the page) through the right current measuring conductor 10, the magnetic flux generated by the current flowing through the right current measuring conductor 10 generates eddy currents in the +y direction, particularly near the narrow current path 13 of the left current measuring conductor 10. Consequently, the current density increases on the right side of the narrow current path 13 on the right.

[0102] In contrast, Figure 15As shown, when the phases are the same, the current density in the current path farther from the other current measuring conductor 10 is higher. That is, in the left current measuring conductor 10, the current concentrates on the left side of the wide current path 14 on the left, while in the right current measuring conductor 10, the current concentrates on the right side of the narrow current path 13 on the right. This is because the magnetic flux generated by the current flowing through one current measuring conductor 10 generates eddy currents in the other current measuring conductor 10. For example, when current flows in the +y direction (inward on the page) through the left current measuring conductor 10, current flows in the +y direction (inward on the page) through the right current measuring conductor 10. The magnetic flux generated by the current flowing through the right current measuring conductor 10 generates eddy currents in the -y direction, particularly near the narrow current path 13 of the left current measuring conductor 10. As a result, the current flowing in the narrow current path 13 of the left current measuring conductor 10 is offset by the eddy current from the other side. As a result, the current density on the left side of the wide current path 14 on the left side increases. When the current density in either the left or right current path of the other current measuring conductor 10 increases due to the influence of the other current measuring conductor 10, arranging the current measuring conductor 10 in an orientation that increases the current density in the wide current path 14 can reduce the error in the magnetic flux density detected by the magnetic detection element 12. As described above, the current density of the left or right current path of the current measuring conductor 10 increases depending on the phase difference with the current flowing in the other current measuring conductor 10. Therefore, whether the current detection device 101 of the reference example or the current detection device 102 of the first embodiment should be adopted also varies depending on the phase difference with the current flowing in the other current measuring conductor 10.

[0103] Above, such as Figure 14 and Figure 15 As shown, when using two asymmetric current measuring conductors 10 having a narrow current path 13 and a wide current path 14, an imbalance in current density occurs due to the phase difference between the currents flowing through the left and right current measuring conductors 10. When the phases differ by 180°, the current concentrates on the inner current path, while when the phases are the same, the current concentrates on the outer current path.

[0104] Figure 16 This is a graph showing the range in which the arrangement configuration of the current detection device 102 according to the first embodiment is effective. Figure 16The points in the rectangles show the errors in the magnetic flux density detected by the current measuring conductor 10 on the left side of the current detection device 101 of the reference example, the points in the white circles show the errors in the magnetic flux density detected by the current measuring conductor 10 on the left side of the current detection device 102 of the first embodiment, the points in the triangles show the errors in the magnetic flux density detected by the current measuring conductor 10 on the right side of the current detection device 103 in the comparative example, the points with asterisks show the errors in the magnetic flux density detected by the current measuring conductor 10 on the left side of the current detection device 103 in the comparative example, and the dotted line shows the errors in the magnetic flux density detected by the current measuring conductor 10 of the single-phase current detection device. Figure 16 The vertical axis in represents the maximum value of the error in the detected magnetic flux density caused by the arrangement of the magnetic detection element 12, and the horizontal axis represents the distance (mm) between the left and right current measurement conductors 10. Figure 16 An example is shown in which the frequency of the alternating current flowing through the two current-measuring conductors 10 is 2000 Hz and the phase difference is 180°.

[0105] like Figure 16 As shown, within the range where the distance between the left and right current measuring conductors 10 is 10 mm or less, the magnetic flux density error of the current detecting device 101 of the reference example is large. In contrast, the magnetic flux density error of the current detecting device 102 of the first embodiment is small, resulting in a large difference in the magnetic flux density errors between the two. However, this difference gradually decreases as the distance between the left and right current measuring conductors 10 increases. When the distance between the left and right current measuring conductors 10 approaches 100 mm, the magnetic flux density errors of the current detecting device 101 of the reference example and the magnetic flux density errors of the current detecting device 102 of the first embodiment both approach those of single-phase current detecting devices. When the distance between the left and right current measuring conductors 10 exceeds 100 mm, the difference between the two becomes almost zero. This is because the farther one current measuring conductor 10 is from the other current measuring conductor 10, the less the influence of eddy currents on the other current measuring conductor 10 becomes.

[0106] Therefore, as described above, when the phases of the AC currents flowing through the two current-measuring conductors 10 differ by 180°, the current detection device 102 of the first embodiment can reduce the detection error of the magnetic flux density caused by the positional offset of the magnetic detection element 12 compared to the current detection device 103 of the comparative example. Furthermore, when the phases of the AC currents flowing through the two current-measuring conductors 10 differ by 180°, the current detection device 102 of the first embodiment can reduce the detection error of the magnetic flux density caused by the positional offset of the magnetic detection element 12 compared to 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 decreases as the distance between the current-measuring conductors 10 increases.

[0107] In addition, if Figure 16 As shown, when the phases of the alternating currents flowing in the two current measuring conductors 10 differ by 180°, the error in the magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 on the right side of the current detection device 103 of the comparative example is close to the value of the error in the magnetic flux density detected by the current measuring conductor 10 on the left side of the current detection device 102 of the first embodiment, and the error in the magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 on the left side of the current detection device 103 of the comparative example becomes a value close to the value of the error in the magnetic flux density detected by the current measuring conductor 10 on the left side of the current detection device 101 of the reference example.

[0108] Figure 17 This is a graph showing the range in which the arrangement configuration of the current detection device 102 according to the first embodiment is effective. Figure 17 The white circle points in the figure show the error of the magnetic flux density detected by the current measuring conductor 10 on the left side of the current detection device 101 of the reference example, the quadrilateral points show the error of the magnetic flux density detected by the current measuring conductor 10 on the left side of the current detection device 102 of the first embodiment, the triangular points show the error of the magnetic flux density detected by the current measuring conductor 10 on the right side of the current detection device 103 in the comparative example, the asterisk points show the error of the magnetic flux density detected by the current measuring conductor 10 on the left side of the current detection device 103 in the comparative example, and the dotted line shows the error of the magnetic flux density detected by the current measuring conductor 10 of the single-phase current detection device. Figure 17 The vertical axis in represents the maximum value of the error in the detected magnetic flux density caused by the arrangement of the magnetic detection element 12, and the horizontal axis represents the distance (mm) between the left and right current measurement conductors 10. Figure 17 An example is shown in which the frequency of the alternating current flowing through the two current-measuring conductors 10 is 2000 Hz and the phase difference is 120°.

[0109] As according to Figure 17 As can be understood, even when the phases of the AC currents flowing through the two current-measuring conductors 10 differ by 120°, the current detection device 102 of the first embodiment can reduce the detection error of the magnetic flux density caused by the positional shift of the magnetic detection element 12 compared to the current detection device 103 of the comparative example, similarly to the case where the phases differ by 180°. Furthermore, even when the phases of the AC currents flowing through the two current-measuring conductors 10 differ by 120°, the current detection device 102 of the first embodiment can reduce the detection error of the magnetic flux density caused by the positional shift of the magnetic detection element 12 compared to the current detection device 101 of the reference example.

[0110] [Effects of the First Embodiment]

[0111] According to the current detection device in the first embodiment, when the phase difference between the alternating currents flowing in the two current measuring conductors 10 is 100° to 180°, by arranging the current paths 14 with large widths in the x-direction so as to face each other, the error in the magnetic flux density detected by the magnetic detection element 12 when the installation position of the magnetic detection element 12 is offset can be reduced, and a decrease in performance caused by positional offset in the installation of the magnetic detection element 12 can be prevented.

[0112] [First Example of Second Embodiment]

[0113] Figure 18 1 is a top view showing the schematic structure of the current detection device 104 in the first example of the second embodiment. Figure 18 As shown, the current detection device 104 includes three current measuring conductors 10. The two outer current measuring conductors 10 of the three current measuring conductors 10 are arranged side by side in the x-direction so that their wide current paths 14 face each other. The central current measuring conductor 10 of the three current measuring conductors 10 is arranged so that its wide current path 14 is on the right. The current measuring conductors 10 are arranged so that the distance A between the left current measuring conductor 10 and the central current measuring conductor 10 is the same as the distance B between the central current measuring conductor 10 and the right current measuring conductor 10 (A = B).

[0114] [Second Example of Second Embodiment]

[0115] Figure 19 1 is a top view showing the schematic structure of the current detection device 106 in the second example of the second embodiment. Figure 19As shown, the current detection device 106 has three current measuring conductors 10. The two current measuring conductors 10 arranged on the outside of the three current measuring conductors 10 are arranged in the x direction in such a manner that the current paths 14 with a large width face each other. The current measuring conductor 10 arranged in the center of the three current measuring conductors 10 is arranged in such a manner that the current path 14 with a large width is on the right. The current measuring conductors 10 are arranged in such a manner that the distance A between the current measuring conductor 10 on the left and the current measuring conductor 10 in the center is larger than the distance B between the current measuring conductor 10 in the center and the current measuring conductor 10 on the right. In this example, the three current measuring conductors 10 can be configured to correspond to the U phase, V phase, and W phase in the three-phase AC, respectively, and the phases of the AC currents flowing in the three current measuring conductors 10 differ by 120°. Figure 19 In the diagram, the current measuring conductor 10 on the left side may correspond to the U phase, the current measuring conductor in the center may correspond to the V phase, and the current measuring conductor 10 on the right side may correspond to the W phase.

[0116] Figure 20 is a graph showing the performance of the current detection device 104 according to the first example of the second embodiment. Figure 21 is a graph showing the performance of the current detection device 106 according to the second example of the second embodiment. Figure 20 and Figure 21 In the example, the performance based on distance A and distance B is compared. Figure 20 A graph showing the frequency-dependent rate of change of the magnetic flux density detected by the magnetic detection element 12 of the V-phase current measuring conductor 10 of the current detection device 104 of the first example is shown. Figure 21 The graph shows the frequency-dependent rate of change of the magnetic flux density detected by the magnetic detection element 12 of the V-phase current measuring conductor 10 of the current detection device 106 of the second example.

[0117] like Figure 20 and Figure 21 As shown, compared to Figure 20 In terms of the situation, Figure 21 Therefore, it can be seen that the error in the magnetic flux density detected by the magnetic detection element 12 is smaller when the distance A>the distance B than when the distance A=the distance B.

[0118] Figure 22 This is a graph comparing the performance when the distance A and the distance B are varied in the second embodiment. Figure 22The horizontal axis shows the movement distance of the central V-phase current measuring conductor 10 from an evenly spaced point (i.e., A=B) in the current detection device of the second embodiment. When the V-phase current measuring conductor 10 is moved closer to the current measuring conductor 10 on the left, the movement distance is negative, and when the V-phase current measuring conductor 10 is moved closer to the current measuring conductor 10 on the right, the movement distance is positive. Figure 22 The vertical axis shows the error in the magnetic flux density detected by the magnetic detection element 12 of the U-phase current measuring conductor 10 .

[0119] Figure 22 The line connecting the points of the quadrilateral shows the case where the frequency of the AC current is 10000 Hz, the line connecting the points of the white circle shows the case where the frequency of the AC current is 5000 Hz, the line connecting the points of the asterisk shows the case where the frequency of the AC current is 2000 Hz, and the line connecting the points of the triangle shows the case where the frequency of the AC current is 1000 Hz.

[0120] like Figure 22 As shown, it can be seen that as the V-phase current measuring conductor 10 approaches the right-hand W-phase current measuring conductor 10, the error in the magnetic flux density detected by the magnetic detection element 12 of the U-phase current measuring conductor 10 decreases. Therefore, the second example current detection device 106 is more preferable than the first example current detection device 104 for the arrangement of the V-phase current measuring conductor 10.

[0121] Figure 23 1 is a plan view showing a schematic structure of a current detection device 107 in a comparative example of the second embodiment. Figure 23 As shown, the current detection device 107 of the comparative example includes three current measuring conductors 10. Each of the three current measuring conductors 10 has a narrow current path 13 on the left and a wide current path 14 on the right. In other words, the three current measuring conductors 10 are arranged so as to face the same direction. The distance A between the left current measuring conductor 10 and the center current measuring conductor 10 is the same as the distance B between the center current measuring conductor 10 and the right current measuring conductor 10 (A = B). The three current measuring conductors 10 are configured to correspond to the U phase, V phase, and W phase of the three-phase AC current, respectively, and the AC currents flowing through the three current measuring conductors 10 differ in phase by 120°.

[0122] Figures 24 to 26 Graphs showing the performance of the current detection device 107 of the comparative example. Figure 24 FIG. 2 shows the frequency-dependent change rate of the magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 on the left side of the current detection device 107 of the comparative example. Figure 25FIG. 2 shows the frequency-dependent change rate of the magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 at the center of the current detection device 107 of the comparative example. Figure 26 The frequency-dependent change rate of the magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 on the right side of the current detection device 107 of the comparative example is shown.

[0123] Figures 24 to 26 The vertical axis shows the rate of change (%) of magnetic flux density based on a frequency of 100 Hz of the alternating current flowing through the current-measuring conductor 10 , and the horizontal axis shows the frequency. Figures 24 to 26 The magnetic detection element 12 is positioned along Figure 2 The arrow A in FIG. 1 represents the rate of change of the magnetic flux density detected by the magnetic detection element 12 when the magnetic detection element 12 is shifted by a predetermined interval in the x direction.

[0124] Figures 24 to 26 The line connecting the points of the white circles shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 7.2 mm, the line connecting the points of the quadrilateral shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 5.2 mm, the line connecting the points of the triangle shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 4.0 mm, the line connecting the points of the diamond shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 2.8 mm, and the line connecting the points of the asterisk shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 0.8 mm.

[0125] like Figures 24 to 26 As shown, the detection error of the magnetic flux density of the magnetic detection element 12 of the current measuring conductor 10 on the left side of the current detection device 107 of the comparative example is small, and the detection error of the magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 in the center and the magnetic detection element 12 of the current measuring conductor 10 on the right side becomes a large value.

[0126] [Effects of the Second Embodiment]

[0127] According to the first example of the second embodiment, current detection device 104 includes three current measuring conductors 10. Two of the three current measuring conductors 10, located on the outer sides, are arranged side by side in the x-direction with wide current paths 14 facing each other. This reduces errors in the magnetic flux density detected by magnetic detection element 12 if the mounting position of magnetic detection element 12 is shifted, thus preventing performance degradation caused by positional shifts in the mounting of magnetic detection element 12.

[0128] According to the second example of current detection device 106 in the second embodiment, current detection device 106 includes three current measuring conductors 10, and the center V-phase current measuring conductor 10 is arranged closer to the right-hand W-phase current measuring conductor 10. This reduces errors in the magnetic flux density detected by magnetic detection element 12 when the mounting position of magnetic detection element 12 is shifted, thereby preventing performance degradation caused by positional shifts in the mounting of magnetic detection element 12.

[0129] [First Example of the Third Embodiment]

[0130] Figure 27 1 is a top view showing the schematic structure of the current detection device 105 in the first example of the third embodiment. Figure 27 As shown, a current detection device 105 according to the first example of the third embodiment includes three current measuring conductors 10. The two outermost current measuring conductors 10 of the three current measuring conductors 10 are arranged side by side in the x-direction so that their smaller current paths 13 face each other. The central current measuring conductor 10 of the three current measuring conductors 10 is arranged so that its wider current path 14 is on the right. The current measuring conductors 10 are arranged so that the distance A between the left current measuring conductor 10 and the central current measuring conductor 10 is the same as the distance B between the central current measuring conductor 10 and the right current measuring conductor 10 (A = B).

[0131] Figures 28 to 31 This graph compares the performance of the current detection device 104 of the first example of the second embodiment and the current detection device 105 of the first example of the third embodiment when the phases of the AC currents flowing through the three current measuring conductors 10 are different by 120 degrees. Figure 28 The frequency-dependent change rate of the magnetic flux density detected by the magnetic detection element 12 of the left-side current measuring conductor 10 of the first example of the current detection device 104 of the second embodiment is shown. Figure 29 FIG4 shows the frequency-dependent change rate of the magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 on the right side of the current detection device 104 of the first example of the second embodiment. Figure 30 FIG4 shows the frequency-dependent change rate of the magnetic flux density detected by the magnetic detection element 12 of the left-side current measuring conductor 10 of the first example of the current detection device 105 of the third embodiment. Figure 31 The frequency-dependent change rate of the magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 on the right side of the current detection device 105 of the first example of the third embodiment is shown.

[0132] Figures 28 to 31The vertical axis shows the rate of change (%) of magnetic flux density based on a frequency of 100 Hz of the alternating current flowing through the current-measuring conductor 10 , and the horizontal axis shows the frequency. Figures 28 to 31 The magnetic detection element 12 is positioned along Figure 2 The arrow A in FIG. 1 represents the rate of change of the magnetic flux density detected by the magnetic detection element 12 when the magnetic detection element 12 is shifted by a predetermined interval in the x direction.

[0133] Figures 28 to 31 The line connecting the points of the white circles shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 7.2 mm, the line connecting the points of the quadrilateral shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 5.2 mm, the line connecting the points of the triangle shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 4.0 mm, the line connecting the points of the diamond shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 2.8 mm, and the line connecting the points of the asterisk shows that the distance between the left end of the gap 11 and the magnetic detection element 12 is 0.8 mm.

[0134] like Figure 28 As shown in FIG. 1 , in the current measuring conductor 10 on the left side of the current detecting device 104 of the first example of the second embodiment, when the magnetic detection element 12 is arranged near the right end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to gradually decrease in accordance with the frequency of the alternating current flowing through the current measuring conductor 10. Similarly, when the magnetic detection element 12 is arranged near the left end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to further gradually decrease in accordance with the frequency of the alternating current flowing through the current measuring conductor 10.

[0135] like Figure 29 As shown, in the current measuring conductor 10 on the right side of the current detecting device 104 of the first example of the second embodiment, when the magnetic detection element 12 is arranged near the right end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to gradually decrease in accordance with the frequency of the alternating current flowing through the current measuring conductor 10. Similarly, when the magnetic detection element 12 is arranged near the left end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to gradually decrease in accordance with the frequency of the alternating current flowing through the current measuring conductor 10.

[0136] like Figure 30As shown in FIG. 1 , in the current measuring conductor 10 on the left side of the current detecting device 105 of the first example of the third embodiment, when the magnetic detection element 12 is positioned near the right end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to increase within a range of +15% to +20% in accordance with the frequency of the alternating current flowing through the current measuring conductor 10. On the other hand, when the magnetic detection element 12 is positioned near the left end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease within a range of -10% to -15% in accordance with the frequency of the alternating current flowing through the current measuring conductor 10.

[0137] like Figure 31 As shown in FIG. 1 , in the current measuring conductor 10 on the right side of the current detecting device 105 of the first example of the third embodiment, when the magnetic detection element 12 is positioned near the right end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to decrease within a range of -10% to -15% in accordance with the frequency of the AC current flowing through the current measuring conductor 10. On the other hand, when the magnetic detection element 12 is positioned near the left end of the gap 11, the magnetic flux density detected by the magnetic detection element 12 tends to increase within a range of +15% to +20% in accordance with the frequency of the AC current flowing through the current measuring conductor 10.

[0138] like Figure 28 and Figure 29 As shown, in current detection device 104 according to the first example of the second embodiment, the width of the error in the magnetic flux density detected by magnetic detection element 12 is smaller when magnetic detection element 12 is positioned near the right end of gap 11 than when magnetic detection element 12 is positioned near the left end of gap 11. This indicates that the error in the magnetic flux density detected by magnetic detection element 12 is smaller even when the mounting position of magnetic detection element 12 is offset.

[0139] like Figure 30 and Figure 31 As shown, in current detection device 105 according to the first example of the third embodiment, the error width of the magnetic flux density detected by magnetic detection element 12 is greater when magnetic detection element 12 is positioned closer to the right end of gap 11 than when magnetic detection element 12 is positioned closer to the left end of gap 11. This indicates that the error in the magnetic flux density detected by magnetic detection element 12 is greater when the mounting position of magnetic detection element 12 is offset.

[0140] As can be seen from the above, when the phases of the alternating currents flowing through the three current measuring conductors 10 differ by 120°, the current detecting device 104 of the first example of the second embodiment exhibits a smaller error in detecting the magnetic flux density due to positional deviation of the magnetic detecting element 12 than the current detecting device 105 of the first example of the third embodiment. Therefore, from the perspective of detecting the magnetic flux density due to positional deviation of the magnetic detecting element 12, the current detecting device 104 of the first example of the second embodiment, in which the two outermost current measuring conductors 10 of the three current measuring conductors 10 are arranged side by side in the x-direction with the wide current paths 14 facing each other, is superior.

[0141] As described above, in the first example of the second embodiment, when the phase difference of the AC current between adjacent current-measuring conductors 10 is close to 120°, it is preferable to arrange the current-measuring conductor 10 so that the distance A between the left current-measuring conductor 10 and the center current-measuring conductor 10 is greater than the distance B between the center current-measuring conductor 10 and the right current-measuring conductor 10. This is presumably because, when focusing on the center current-measuring conductor 10 and the right current-measuring conductor 10, the same effects as those of the first embodiment are achieved. Therefore, the arrangement of the second embodiment is preferably used when the phase difference of the AC current between adjacent current-measuring conductors 10 is 120°.

[0142] Therefore, in the first example of the second embodiment, the three current measuring conductors 10 may correspond to the U phase, V phase, and W phase of the three-phase AC, respectively, and the AC currents flowing through the three current measuring conductors 10 may differ in phase by 120°.

[0143] On the other hand, in the third embodiment, when the phase difference of the AC current between adjacent current measuring conductors 10 is within the range of 0° to 80°, it is preferable to arrange the current measuring conductors 10 so that the distance A between the left current measuring conductor 10 and the center current measuring conductor 10 is smaller than the distance B between the center current measuring conductor 10 and the right current measuring conductor 10. This is presumably because, when focusing on the center current measuring conductor 10 and the left current measuring conductor 10, the same effect as in the reference example can be achieved.

[0144] Therefore, the first example of the third embodiment is preferably used when the phase difference of the alternating current between adjacent current-measuring conductors 10 is within a range of 0° to 80°.

[0145] In addition, the configuration of the second and third embodiments is not limited to the case of configuring three current measuring conductors 10, that is, it is not limited to the case of using three-phase AC using three current measuring conductors 10. When configuring four or more current measuring conductors 10, it can be applied to any three adjacent current measuring conductors 10.

[0146] [Second Example of the Third Embodiment]

[0147] Figure 32 1 is a top view showing the schematic structure of the current detection device 108 in the second example of the third embodiment. Figure 32 As shown, the current detection device 108 includes three current measuring conductors 10. The two outer current measuring conductors 10 of the three current measuring conductors 10 are arranged side by side in the x-direction so that their narrow current paths 13 face each other. The central current measuring conductor 10 of the three current measuring conductors 10 is arranged so that its narrow current path 13 is on the left. The current measuring conductors 10 are arranged so that the distance A between the left current measuring conductor 10 and the central current measuring conductor 10 is smaller than the distance B between the central current measuring conductor 10 and the right current measuring conductor 10.

[0148] [Effects of the Third Embodiment]

[0149] according to Figure 27 The first example of a current detecting device 105 in the third embodiment shown in the figure includes three current measuring conductors 10. Two of the three current measuring conductors 10, located on the outer sides, are arranged side by side in the x-direction with narrow current paths 13 facing each other. This arrangement reduces errors in the magnetic flux density detected by the magnetic detecting element 12 when the mounting position of the magnetic detecting element 12 is misaligned, preventing performance degradation caused by misalignment of the magnetic detecting element 12.

[0150] according to Figure 32 In the second example of the third embodiment shown, current detection device 108 includes three current measuring conductors 10, with the center V-phase current measuring conductor 10 positioned closer to the left U-phase current measuring conductor 10. This reduces errors in the magnetic flux density detected by magnetic detection element 12 when the mounting position of magnetic detection element 12 is shifted, thus preventing performance degradation caused by positional shifts in the mounting of magnetic detection element 12.

[0151] [Other embodiment 1]

[0152] Figure 33 A top view schematically illustrates the structure of a current measuring conductor 10a in another embodiment 1. The current measuring conductor 10a in another embodiment 1 includes a gap 11, a magnetic detection element 12, a narrow current path 13, a wide current path 14, two main bodies 15, and a slit 16. The magnetic detection element 12 is supported by the substrate in a manner fixed thereto. The substrate is inserted into the slit 16 and fixed to the current measuring conductor 10a. The two current paths 13 and 14 are respectively arranged inwardly of the outer edges of the two main bodies 15 in the direction in which the two current paths 13 and 14 are arranged. The current measuring conductor 10a in another embodiment 1 may be used in place of the current measuring conductor 10 in the first embodiment described above.

[0153] [Other embodiment 2]

[0154] Figure 34 This is a perspective view showing a schematic structure of a current measuring conductor 10b in another second embodiment. Figure 35 This is a plan view showing an example of a schematic structure of a current measuring conductor 10b in another second embodiment. Figure 36 1 is a side view showing an example of the schematic structure of the current measuring conductor 10b in another embodiment 2. In the first embodiment described above, as Figure 2 As shown in FIG. 1 , the magnetic detection element 12 is arranged inside the gap 11 in a top view. However, the magnetic detection element 12 may be arranged above or below the current path 13 having a small width. Figures 34 to 36 As shown, in the current measuring conductor 10 b according to another second embodiment, the magnetic detection element 12 is arranged above the current path 13 having a small width. Figure 35 The arrow L shown in FIG. 1 indicates the range of positional deviation of the magnetic detection element 12 when it is mounted on the current measuring conductor 10 b. Figure 35 As shown, the magnetic detection element 12 is sometimes mounted offset in the x-direction by the width of the arrow L. Thus, in the current measuring conductor 10 or the like, the magnetic detection element 12 may be arranged so as to overlap with the narrow current path 13 in a plan view, or so as to overlap with the wide current path 14 in a plan view, or so as to overlap with the gap 11 between the wide current path 14 and the narrow current path 13 in a plan view, or so as to be positioned to the side of the wide current path 14 in a plan view, or so as to be positioned to the side of the narrow current path 13 in a plan view.

[0155] Figure 37 and Figure 38This is a graph comparing the performance of the current detection device 101 of the reference example and the current detection device 102 of the first embodiment when using the current measuring conductor 10 b of the second embodiment. Figure 37 and Figure 38 FIG. 1 shows a change in the magnetic flux density detected by the magnetic detection element 12 due to frequency when the phases of the alternating currents flowing through the two current measuring conductors 10 b differ by 180°. Figure 37 and Figure 38 The magnetic detection element 12 is positioned along Figure 35 The arrows L in FIG. 1 are shifted at predetermined intervals in the x-direction and represent the rate of change of the magnetic flux density detected by the magnetic detection element 12 .

[0156] Figure 37 and Figure 38 The vertical axis shows the rate of change (%) of the magnetic flux density when the frequency of the alternating current flowing through the current measuring conductor 10 b is 100 Hz, and the horizontal axis shows the frequency. Figure 37 FIG. 2 shows the magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 on the left side of the current detection device 101 of the reference example. Figure 38 The magnetic flux density detected by the magnetic detection element 12 of the current measuring conductor 10 on the left side of the current detection device 102 according to the first embodiment is shown.

[0157] Figure 37 and Figure 38 The line connecting the points marked with × shows a 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 points marked with white circles shows a 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 points marked with quadrilateral shows a 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 points marked with triangles shows a 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 points marked with diamonds shows a 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 points marked with asterisks shows a case where the distance between the left end of the current path 13 and the magnetic detection element 12 is 0 mm.

[0158] like Figure 37 As shown, in reference example current detection device 101, the error width of the magnetic flux density detected by magnetic detection element 12 is greater when magnetic detection element 12 is positioned closer to the right end of current path 13 than when magnetic detection element 12 is positioned closer to the left end of current path 13. This indicates that the error in the magnetic flux density detected by magnetic detection element 12 is greater when the mounting position of magnetic detection element 12 is offset.

[0159] like Figure 38 As shown, in the current detection device 102 of the first embodiment, the width of the error in the magnetic flux density detected by the magnetic detection element 12 is smaller when the magnetic detection element 12 is positioned closer to the right end of the current path 13 than when the magnetic detection element 12 is positioned closer to the left end of the current path 13. This indicates that the error in the magnetic flux density detected by the magnetic detection element 12 is smaller even when the mounting position of the magnetic detection element 12 is offset.

[0160] As described above, even when the current measuring conductor 10b of the second embodiment is used instead of the current measuring conductor 10 of the first embodiment, even when the AC currents flowing through the two current measuring conductors 10 differ in phase by 180°, the current detecting device 102 of the first embodiment, arranged in the x-direction with wide current paths 14 facing each other, shows a small detection error in the magnetic flux density caused by positional deviation of the magnetic detecting element 12. Therefore, it can be seen that the same principle as in the first embodiment holds true.

[0161] [Other embodiment 3]

[0162] In the first and second embodiments described above, the two current paths 13 and 14 have the same thickness but different widths. However, the two current paths 13 and 14 only need to have different cross-sectional areas; for example, they may have the same width but different thicknesses. In this case, the thickness of the current path 14 may be thicker than that of the current path 13. Alternatively, 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 greater than that of the current path 13, and the thickness of the current path 14 may be thicker than that of the current path 13. Furthermore, in the first and second embodiments described above, the two or three current measuring conductors 10 have the same shape. However, different shapes may be employed. Furthermore, in the various other embodiments described above, each current measuring conductor 10a, etc., is described as having a single magnetic detection element 12. However, the current measuring conductor 10a, etc., may alternatively have two or more magnetic detection elements 12 arranged in the x-axis direction.

[0163] While the present invention has been described above using embodiments, the scope of protection of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications or improvements can be made to the above embodiments. As can be seen from the claims, embodiments resulting from such modifications or improvements are also encompassed within the scope of protection of the present invention.

[0164] It should be noted that the order in which actions, processes, steps, and stages, etc., are executed in the apparatus, system, program, or method described in the claims, specifications, and drawings may be implemented in any order unless otherwise expressly stated, such as "before," "prior to," or "before," and the output of a previous process is used for a subsequent process. Even if the action flow in the claims, specifications, and drawings is described using phrases such as "first," "next," or "next," for convenience, it does not necessarily mean that the actions must be executed in that order.

[0165] Description of Reference Numerals

[0166] 10, 10a, 10b: current measuring conductors; 11: gap; 12: magnetic detection element; 13: current path; 14: current path; 15: main body; 16: slit; 101-108: current detection device.

Claims

1. A current detection device, characterized in that: The invention comprises at least two bus bars, wherein the bus bars include a magnetic detection element, a first current path with a large cross-sectional area and a second current path with a small cross-sectional area sandwiching the magnetic detection element, The at least two bus bars are arranged so that the first current paths face each other.

2. The current detection device according to claim 1, characterized in that: Another bus bar is further provided between the at least two bus bars, and the other bus bar includes a magnetic detection element, a third current path with a large cross-sectional area and a fourth current path with a small cross-sectional area that sandwich the magnetic detection element.

3. A current detection device, characterized in that: The invention comprises at least two bus bars, wherein the bus bars include a magnetic detection element, a first current path with a large cross-sectional area and a second current path with a small cross-sectional area sandwiching the magnetic detection element, Another bus bar is further provided between the at least two bus bars, and the other bus bar includes a magnetic detection element, a third current path with a large cross-sectional area and a fourth current path with a small cross-sectional area that sandwich the magnetic detection element.

4. The current detection device according to claim 3, characterized in that: The other bus bar is arranged such that a distance between the other bus bar and the bus bar facing the fourth current path of the other bus bar is greater than a distance between the other bus bar and the bus bar facing the third current path of the other bus bar.

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

6. The current detection device according to claim 3, characterized in that: The other bus bar is arranged such that a distance between the other bus bar and the bus bar facing the third current path of the other bus bar is greater than a distance between the other bus bar and the bus bar facing the fourth current path of the other bus bar.

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

8. The current detection device according to any one of claims 1 to 7, characterized in that: The first current path and the second current path have the same thickness and different widths.

9. The current detection device according to any one of claims 1 to 7, characterized in that: The bus bar includes two main body parts connected to the first current path and the second current path. The first current path and the second current path are respectively arranged at positions inside of outer edges of the two main body portions in the direction in which the first current path and the second current path are arranged.

10. The current detection device according to claim 9, characterized in that: Each of the two main body parts includes a slit into which a substrate for supporting the magnetic detection element is inserted.

11. A current detection device, characterized in that: At least two bus bars are provided, each bus bar having a magnetic detection element, a first current path with a large cross-sectional area, and a second current path with a small cross-sectional area, The at least two bus bars are arranged so that the first current paths face each other.

12. The current detection device according to claim 11, characterized in that: Another bus bar disposed between the at least two bus bars is further provided, and the other bus bar includes 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.

13. A current detection device, characterized in that: At least two bus bars are provided, each bus bar having a magnetic detection element, a first current path with a large cross-sectional area, and a second current path with a small cross-sectional area, Another bus bar disposed between the at least two bus bars is further provided, and the other bus bar includes 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.

14. The current detection device according to claim 13, characterized in that: The other bus bar is arranged such that a distance between the other bus bar and the bus bar facing the fourth current path of the other bus bar is greater than a distance between the other bus bar and the bus bar facing the third current path of the other bus bar.

15. The current detection device according to claim 14, characterized in that: The at least two bus bars are arranged so that the first current paths face each other.

16. The current detection device according to claim 13, characterized in that: The other bus bar is arranged such that a distance between the other bus bar and the bus bar facing the third current path of the other bus bar is greater than a distance between the other bus bar and the bus bar facing the fourth current path of the other bus bar.

17. The current detection device according to claim 16, characterized in that: The at least two bus bars are arranged so that the second current paths face each other.

18. The current detection device according to any one of claims 11 to 17, characterized in that: In the at least two bus bars, the magnetic detection element is arranged so as to overlap with the second current path in a plan view.

19. The current detection device according to any one of claims 11 to 17, characterized in that: In the at least two bus bars, the magnetic detection element is arranged so as to overlap with a gap between the first current path and the second current path in a plan view.

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