Current sensor

Abstract

To provide a current sensor capable of suppressing magnetic saturation of a magnetic flux concentrating plate while suppressing an increase in size, using a bent bus bar.SOLUTION: A current sensor 1 includes: a bus bar 11 in which a second part 112 protrudes from one end edge 111a of a first part 111; a magnetic flux concentrating plate 12 that surrounds an intermediate portion 111b of the first part 111 of the bus bar 11 so that a cross-sectional shape thereof is C-shaped and concentrates magnetic flux generated when a current I flows through the bus bar 11 around the intermediate portion 111b, the magnetic flux concentrating plate 12 being arranged such that an opening 12a of the C shape opens toward a protruding direction D11 of the second part 112; and a sensor unit 13 for detecting the current I with a Hall element 131 via the magnetic flux concentrated by the magnetic flux concentrating plate 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a current sensor that uses a Hall element to detect the current of an object to be measured. [Background technology]

[0002] Conventionally, current sensors that use a Hall element to detect the current of a measurement target are known (see, for example, Patent Document 1). In many cases, current sensors such as those described in Patent Document 1 pass the current of the measurement target through a bus bar, and a Hall element disposed near the bus bar detects the current via magnetic flux generated when the current flows through the bus bar. In addition, to concentrate the magnetic flux around the Hall element and increase the current measurement sensitivity, a magnetic flux concentrator plate made of a soft magnetic material is provided to surround the Hall element and the middle portion of the bus bar. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-232246 Summary of the Invention [Problem to be solved by the invention]

[0004] In some current sensors, a curved busbar having a strip-shaped first portion and a strip-shaped second portion protruding from one edge of the first portion is used. When the above-described magnetic flux concentrator is provided on such a curved busbar, magnetic saturation of the magnetic flux concentrator is more likely to occur than when a straight busbar is used, which can result in reduced measurement accuracy. While it is possible to suppress magnetic saturation by increasing the size of the magnetic flux concentrator, this is not particularly desirable because it would increase the size of the sensor itself.

[0005] Therefore, in view of the above-mentioned problems, an object of the present invention is to provide a current sensor that uses a curved bus bar, while preventing an increase in size and suppressing magnetic saturation of a flux concentrator plate. [Means for solving the problem]

[0006] In order to achieve the above object, a current sensor includes: a busbar, which is made of a conductive metal and through which a current to be measured flows, and which has a strip-shaped first portion and a strip-shaped second portion protruding from one end edge of the first portion in a protruding direction that intersects with the front and back surfaces of the first portion; a magnetic flux concentrator, which is made of a soft magnetic material and has a bent plate shape that surrounds a midpoint in the longitudinal direction of the first portion of the busbar so that its cross section orthogonal to the longitudinal direction of the busbar forms a C-shape, and which converges magnetic flux generated by a current when the current flows through the busbar around the midpoint, the magnetic flux concentrator being arranged so that an opening of the C-shape faces in the protruding direction; and a sensor unit which has a Hall element for detecting current, the Hall element being arranged between the opening and the midpoint so as to be surrounded by the magnetic flux concentrator, and which detects the current via the magnetic flux converged by the magnetic flux concentrator. [Effects of the Invention]

[0007] According to the current sensor described above, it is possible to suppress magnetic saturation of the flux concentrator plate while using a curved bus bar and preventing an increase in size. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a current sensor according to an embodiment; [Figure 2] 2 is a side view of the current sensor shown in FIG. 1 as viewed in the direction of arrow V11 in FIG. [Figure 3] 2 is a cross-sectional view of the current sensor shown in FIG. 1 taken along line V12-V12 in FIG. 1. [Figure 4]FIG. 4 is a perspective view showing a current sensor as a comparative example to the current sensor shown in FIGS. 1 to 3. [Figure 5] 5 is a side view of the current sensor shown in FIG. 4, as viewed in the direction of arrow V51 in FIG. [Figure 6] 6 is a schematic diagram showing how magnetic flux generated when a current flows through a bus bar is absorbed by a magnetic flux concentrator plate in the current sensor of the comparative example shown in FIGS. 4 and 5. FIG. [Figure 7] 4 is a schematic diagram showing how absorption of magnetic flux by a flux concentrator plate is suppressed when a current flows through a bus bar in the current sensor of the embodiment shown in FIGS. 1 to 3. FIG. [Figure 8] 6 is a graph showing the magnetic flux density at the magnetic flux concentrator plates of the current sensors of the embodiments shown in Figures 1 to 3 and the current sensors of the comparative examples shown in Figures 4 and 5, together with a current sensor of a standard form using a straight-shaped bus bar. [Figure 9] FIG. 9 is a perspective view of a current sensor in a reference configuration in which the magnetic flux density at the flux concentrator plate is shown in the graph of FIG. 8. [Figure 10] This is a graph showing that the magnetic flux density at the position where the Hall element is arranged is approximately the same among the current sensors of the embodiment shown in Figures 1 to 3, the current sensors of the comparative examples shown in Figures 4 and 5, and the current sensor of the reference form shown in Figure 9. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the current sensor will now be described.

[0010] Fig. 1 is a perspective view showing a current sensor according to an embodiment, and Fig. 2 is a side view of the current sensor shown in Fig. 1 as seen from the direction of arrow V11 in Fig. 1. Also, Fig. 3 is a cross-sectional view of the current sensor shown in Fig. 1 taken along line V12-V12 in Fig. 1.

[0011] The current sensor 1 of this embodiment detects a current I to be measured using a Hall element 131, and includes a bus bar 11, a magnetic flux concentrator plate 12, and a sensor portion 13.

[0012] The busbar 11 is made of a conductive metal and is a component through which a current I to be measured flows. The busbar 11 has a first portion 111 and a second portion 112. The first portion 111 is a long, strip-shaped portion, and the second portion 112 is a short, strip-shaped portion that protrudes from one end edge 111a of the first portion 111 in the busbar longitudinal direction D12 in a protruding direction D11 that intersects with the front and back surfaces of the first portion 111 and is shorter than the first portion 111. In this embodiment, the busbar 11 is a bent component formed only by the first portion 111 and the second portion 112 so as to form an L shape in a side view from a direction (direction of arrow V11) perpendicular to the protruding direction D11 and the busbar longitudinal direction D12. Each end of the L-shaped busbar 11 has a through-hole 113 for connecting to the component to be measured by a screw or the like.

[0013] The magnetic flux concentrator plate 12 is a member made of a soft magnetic material and has a bent plate shape that surrounds a middle portion 111b of the first portion 111 of the busbar 11 in the busbar longitudinal direction D12, such that the cross section perpendicular to the busbar longitudinal direction D12 forms a C-shape. The magnetic flux concentrator plate 12 converges magnetic flux φ11 ( FIG. 2 ), which is generated by a current I when the current I flows through the busbar 11, around the middle portion 111b of the first portion 111. The magnetic flux concentrator plate 12 is disposed at the middle portion 111b of the first portion 111 such that an opening 12a of the C-shape opens toward the protruding direction D11 of the second portion 112. The magnetic flux concentrator plate 12 is disposed at a position closer to the one edge 111a of the first portion 111 from which the second portion 112 protrudes, or at an opposite edge 111c thereof, in the busbar longitudinal direction D12. More specifically, magnetic flux concentrator plate 12 is disposed at a position closer to one end edge 111a than to the center of first portion 111 in busbar longitudinal direction D12.

[0014] In this embodiment, the magnetic flux concentrator plate 12 is a rectangular cylindrical folded member with a portion of the peripheral wall cut out as an opening 12a, and comprises a bottom plate portion 121, a pair of arm plate portions 122, and a pair of top plate portions 123.

[0015] The bottom plate portion 121 of the magnetic flux concentrator 12 is a portion that faces one of the front and rear surfaces of the intermediate portion 111b of the first portion 111, opposite the surface on which the Hall element 131 is disposed. The bottom plate portion 121 is a rectangular plate-shaped portion that extends longer than the width dimension T11 of the first portion 111 in a flux concentrator longitudinal direction D14 along the busbar width direction D13 of the first portion 111. The pair of arm plate portions 122 are a pair of rectangular plate-shaped portions that protrude from both end edges of the bottom plate portion 121 in the flux concentrator longitudinal direction D14 in the protruding direction D11 of the second portion 112. The pair of top plate portions 123 are a pair of rectangular plate-shaped portions that extend from the protruding end edges of the pair of arm plate portions 122 along the flux concentrator longitudinal direction D14 so as to face the surface of the intermediate portion 111b of the first portion 111 on the side on which the Hall element 131 is disposed. The extending edges of the pair of top plate portions 123 are spaced apart from each other so as to form an opening 12a in the magnetic flux concentrator plate 12.

[0016] The sensor unit 13 has a Hall element 131 for detecting current, and is disposed so that the Hall element 131 is located between the opening 12a and the intermediate portion 111b of the first portion 111 and is surrounded by the magnetic flux concentrator plate 12. In this case, the Hall element 131 is disposed closer to the opening 12a in the magnetic flux concentrator plate 12 than the first portion 111 in the protruding direction D11 of the second portion 112. The sensor unit 13 detects the current I via the magnetic flux φ11 converged by the magnetic flux concentrator plate 12 using the Hall element 131. The sensor unit 13 includes the Hall element 131 and a sensor substrate 132. The Hall element 131 is a rectangular flat-plate element that detects the current I flowing through the busbar 11 via the magnetic flux φ11. The sensor substrate 132 is a rectangular flat-plate circuit board on which the Hall element 131 is mounted and on which a circuit for amplifying the detection result of the Hall element 131 is formed.

[0017] Before continuing with the description of the current sensor 1 of this embodiment, a comparative example to the current sensor 1 will be described.

[0018] Fig. 4 is a perspective view showing a current sensor that is a comparative example to the current sensors shown in Figs. 1 to 3, and Fig. 5 is a side view of the current sensor shown in Fig. 4 as seen from the direction of arrow V51 in Fig. 4. In Figs. 4 and 5, only components that are equivalent to the components shown in Figs. 1 to 3 and that are necessary for explanation are assigned the same reference numerals as in Figs. 1 to 3. Furthermore, current sensor 5 of the comparative example has a sensor unit that is the same as sensor unit 13 shown in Figs. 1 and 3, but this sensor unit is not shown in Fig. 4.

[0019] The current sensor 5 of the comparative example shown in FIGS. 4 and 5 includes an L-shaped bus bar 11 and a C-shaped magnetic flux concentrator 12 similar to those in FIGS. 1 to 3, but the arrangement of the magnetic flux concentrator 12 relative to the bus bar 11 is different. In this current sensor 5 of the comparative example, the magnetic flux concentrator 12 is arranged so that the opening 12a of the C-shape faces away from the protruding direction D11 of the second portion 112. In addition, in the current sensor 5 of the comparative example, the magnetic flux concentrator 12 is arranged in the center of the first portion 111 with respect to the bus bar longitudinal direction D12. Note that in FIGS. 4 and 5, the current sensor 5 of the comparative example is shown with its up-down orientation in the figures reversed from that in FIGS. 1 and 2, i.e., the protruding direction D11 of the second portion 112 faces downward in the figures.

[0020] In current sensor 5 of the comparative example, magnetic flux φ11 generated when current I flows through bus bar 11 is absorbed by flux concentrator plate 12 as follows.

[0021] Fig. 6 is a schematic diagram showing how the magnetic flux generated when a current flows through the busbar is absorbed by the flux concentrator plates in the current sensor of the comparative example shown in Fig. 4 and Fig. 5. Fig. 6 shows the current sensor 5 of the comparative example in a plan view seen from the direction V52 in Fig. 4 and a plan view seen from the direction V53 in Fig. 6. The direction V53 in Fig. 6 is the direction in which the current sensor 5 of the comparative example is viewed from the protruding side of the second portion 112 of the busbar 11.

[0022] In the current sensor 5 of the comparative example, the magnetic flux concentrator plate 12 is arranged such that the bottom plate portion 121 faces the protruding side of the second portion 112. In this arrangement, when a current I flows through the bus bar 11, the bottom plate portion 121 of the magnetic flux concentrator plate 12 is placed in the magnetic flux φ11 generated around each of the first portion 111 and the second portion 112. In this case, in the C-shaped magnetic flux concentrator plate 12, the continuous bottom plate portion 121 is on the side that absorbs the magnetic flux φ11, and therefore the magnetic flux φ11 around each of the first portion 111 and the second portion 112 is absorbed by the bottom plate portion 121, increasing the magnetic flux density in the magnetic flux concentrator plate 12.

[0023] 5, in the current sensor 5 of the comparative example, the magnetic flux concentrator plate 12 is disposed in the center of the first portion 111 in the busbar longitudinal direction D12. As a result, of the magnetic flux φ11 generated around the first portion 111 surrounded by the magnetic flux concentrator plate 12, the magnetic flux φ11a from the one end edge 111a side where the second portion 112 protrudes is also absorbed by the bottom plate portion 121, and the magnetic flux density in the magnetic flux concentrator plate 12 is further increased.

[0024] In contrast to this comparative current sensor 5, in the current sensor 1 of the embodiment shown in Figures 1 to 3, absorption of magnetic flux φ11 by magnetic flux concentrator plate 12 when current I flows through bus bar 11 is suppressed as follows.

[0025] 7 is a schematic diagram showing how the flux concentrator plates suppress absorption of magnetic flux when a current flows through the busbar in the current sensor of the embodiment shown in FIGS. 1 to 3. Fig. 7 shows the current sensor 1 of this embodiment in a plan view as seen from the V13 direction in FIG. 1 and a plan view as seen from the V14 direction in FIG. 7. The V14 direction in FIG. 7 is the direction in which the current sensor 1 of this embodiment is viewed from the protruding side of the second portion 112 of the busbar 11. Note that, in FIG. 7, the flux concentrator plates 12 are shown disposed at the center of the first portion 111 in the busbar longitudinal direction D12, for easy comparison with the current sensor 5 of the comparative example shown in FIG. 6.

[0026] In the current sensor 1 of this embodiment, the magnetic flux concentrator 12 is disposed such that the opening 12a between the pair of top plate portions 123 faces the protruding side of the second portion 112. In this arrangement, when a current I flows through the busbar 11, the opening 12a side of the magnetic flux concentrator 12 is placed in the magnetic flux φ11 generated around each of the first portion 111 and the second portion 112. In this case, in the C-shaped magnetic flux concentrator 12, the bottom plate portion 121 facing the opening 12a is the absorption side of the magnetic flux φ11, and the opening 12a side is the emission side of the magnetic flux φ11, as described above. The magnetic flux φ11 emitted from the opening 12a side blocks the magnetic flux φ11 around the second portion 112 from flowing toward the magnetic flux concentrator 12. Furthermore, even if the magnetic flux φ11 around the second portion 112 is absorbed by the opening 12a side, it is immediately emitted from the opening 12a side. As a result, the absorption by the flux concentrator plate 12 of the magnetic flux φ11 around the second portion 112 is suppressed, and the magnetic flux density at the flux concentrator plate 12 is reduced accordingly.

[0027] 1 and 2, in the current sensor 1 of this embodiment, the magnetic flux concentrator plate 12 is disposed in a position, in the busbar longitudinal direction D12, that is closer to one end edge 111a, from which the second portion 112 protrudes, of the two end edges of the first portion 111. As a result, of the magnetic flux φ11 generated around the first portion 111, absorption of the magnetic flux φ11 from the one end edge 111a side is suppressed, and the magnetic flux density at the magnetic flux concentrator plate 12 is further reduced accordingly.

[0028] FIG. 8 is a graph showing the magnetic flux density at the flux concentrator plates of the current sensors of the embodiments shown in FIGS. 1 to 3 and the current sensors of the comparative examples shown in FIGS. 4 and 5, together with a current sensor of a reference configuration using a straight busbar. FIG. 9 is a perspective view showing the current sensor of the reference configuration, whose magnetic flux density at the flux concentrator plates is shown in the graph of FIG. 8. Note that in FIG. 9, only those components equivalent to those shown in FIGS. 1 to 5 that are necessary for explanation are assigned the same reference numerals as in FIGS. 1 to 5. Furthermore, although the current sensor 6 of the reference configuration includes a sensor unit that is the same as the sensor unit 13 shown in FIGS. 1 and 3, this sensor unit is not shown in FIG. 9.

[0029] First, the current sensor 6 of the standard configuration shown in Fig. 9 will be described. In this current sensor 6 of the standard configuration, the bus bar 61 through which the current I to be measured flows has a simple straight shape, unlike the L-shaped bus bar 11 shown in Figs. 1 to 5. The magnetic flux concentrator plate 12 surrounding this straight bus bar 61 is a C-shaped member similar to that shown in Figs. 1 to 5.

[0030] A comparison of the magnetic flux densities at the magnetic flux concentrator plate 12 of the current sensor 6 of the reference configuration, the current sensor 1 of the above-described embodiment, and the current sensor 5 of the comparative example yields the results shown in graph G1 of FIG. 8 . Graph G1 of FIG. 8 shows the magnetic flux density at the magnetic flux concentrator plate 12 of each configuration as the distance from the protruding edge 111a of the second portion 112 to the magnetic flux concentrator plate 12 increases. For the current sensor 6 of the reference configuration using a straight busbar 61, the graph shows the magnetic flux density as the distance from the edge 61a of the busbar 61 to the magnetic flux concentrator plate 12 increases. The horizontal axis of graph G1 represents the distance [mm] to the magnetic flux concentrator plate 12, and the vertical axis represents the magnetic flux density [mT] of the magnetic flux concentrator plate 12. The magnetic flux density in the current sensor 1 of the embodiment is indicated by a solid line L1, and the magnetic flux density in the current sensor 5 of the comparative example is indicated by a dashed line L2. The magnetic flux density in the current sensor 6 of the reference configuration is indicated by a dashed line L3.

[0031] A comparison of the three types of magnetic flux densities in graph G1 of Figure 8 shows that the magnetic flux density is lowest in current sensor 1 of the embodiment in which opening 12a of magnetic flux concentrator plate 12 faces the protruding side of second portion 112. On the other hand, current sensor 5 of the comparative example in which opening 12a faces the side opposite to the protruding side of second portion 112 has the highest magnetic flux density because the magnetic flux around second portion 112 is absorbed by bottom plate portion 121 on the absorbing side, as described above. The magnetic flux density in current sensor 6 of the standard configuration in which second portion 112 does not protrude is approximately intermediate between the magnetic flux densities of these embodiments and the comparative example.

[0032] In the current sensor 1 of the embodiment, the magnetic flux density gradually increases as the distance between the flux concentrator plate 12 and the one edge 111a at which the second portion 112 protrudes increases. This is because an increase in the amount of magnetic flux φ11 absorbed by the bottom plate portion 121 from the portion of the first portion 111 between the one edge 111a and the flux concentrator plate 12 increases. On the other hand, in the current sensor 5 of the comparative example, the magnetic flux density gradually decreases as the distance between the flux concentrator plate 12 and the one edge 111a increases. This is because the decrease in the amount of magnetic flux φ11 absorbed from the second portion 112 exceeds the increase in the amount of magnetic flux φ11 absorbed from the first portion 111. The magnetic flux density in the current sensor 6 of the reference configuration is substantially constant regardless of the position of the flux concentrator plate 12.

[0033] As described above, in the three types of configurations including the embodiment, there are differences in the magnetic flux density at the magnetic flux concentrator plate 12, but on the other hand, the magnetic flux density at the position where the Hall element 131 that detects the magnetic flux is arranged is approximately the same value as follows.

[0034] Fig. 10 is a graph showing that the magnetic flux density at the arrangement position of the Hall element is approximately the same among the current sensor of the embodiment shown in Figs. 1 to 3, the current sensor of the comparative example shown in Figs. 4 and 5, and the current sensor of the reference configuration shown in Fig. 9. In graph G2 of Fig. 10, the horizontal axis also represents the distance [mm] to the magnetic flux concentrator plate 12. On the other hand, the vertical axis represents the magnetic flux density [mT] at the arrangement position of the Hall element 131. The magnetic flux density in the current sensor 1 of the embodiment is indicated by a solid line L1, the magnetic flux density in the current sensor 5 of the comparative example is indicated by a dashed line L2, and the magnetic flux density in the current sensor 6 of the reference configuration is indicated by a dashed line L3.

[0035] 10, the magnetic flux density at the arrangement position of the Hall element 131 is approximately the same among the current sensor 1 of the embodiment, the current sensor 5 of the comparative example, and the current sensor 6 of the reference configuration. In other words, in the current sensor 1 of the embodiment, the magnetic flux density of the flux concentrator plate 12 is kept lower than in the other configurations, while the magnetic flux for measuring the current detected by the Hall element 131 is ensured to be sufficiently large, approximately the same as in the other configurations.

[0036] 1 to 3, the current sensor 1 according to the embodiment shown in FIGS. 1 to 3 can achieve the following effects. That is, in this embodiment, the C-shaped magnetic flux concentrator 12 surrounds the intermediate portion 111b of the first portion 111 of the curved busbar 11, and is disposed so that the opening 12a of the C-shape opens toward the protruding direction D11 of the second portion 112. In the C-shaped magnetic flux concentrator 12, the side facing the opening 12a is the side that absorbs the magnetic flux φ11, and the side facing the opening 12a is the side that releases the magnetic flux φ11. Because the magnetic flux concentrator 12 is disposed so that the opening 12a faces the protruding direction D11 of the second portion 112, the magnetic flux φ11 generated around the second portion 112 is less likely to be absorbed by the magnetic flux concentrator 12, and magnetic saturation of the magnetic flux concentrator 12 is suppressed. In this way, the arrangement of the C-shaped flux concentrator 12 suppresses magnetic saturation when a curved busbar 11 is used, eliminating the need to increase the size of the flux concentrator 12 and suppressing an increase in the size of the current sensor 1. In other words, according to this embodiment, while using a curved busbar 11, magnetic saturation of the flux concentrator 12 can be suppressed without increasing the size.

[0037] In this embodiment, the bus bar 11 is an L-shaped member, and the magnetic flux concentrator plate 12 is disposed at a position closer to one edge 111a of the first portion 111, between one edge 111a from which the second portion 112 protrudes and the other edge 111c on the opposite side. With this configuration, of the magnetic flux φ11 generated around the first portion 111 surrounded by the magnetic flux concentrator plate 12, absorption of the magnetic flux φ11 from the one edge 111a side from which the second portion 112 protrudes is suppressed, thereby further suppressing magnetic saturation of the magnetic flux concentrator plate 12.

[0038] Furthermore, in this embodiment, magnetic flux concentrator plate 12 is disposed closer to one edge 111a than to the center of first portion 111. With this configuration, the distance between one edge 111a of first portion 111 and magnetic flux concentrator plate 12 is further reduced, which reduces the absorption of magnetic flux φ11 from one edge 111a, thereby further suppressing magnetic saturation of magnetic flux concentrator plate 12.

[0039] In this embodiment, magnetic flux concentrator 12 includes bottom plate 121, a pair of arm plate portions 122, and a pair of top plate portions 123. With this configuration, the distance between the inner surface of magnetic flux concentrator 12 and first portion 111 can be reduced compared to, for example, a case where the magnetic flux concentrator is formed in a C-shape with a portion of the peripheral wall of a cylinder cut out, and therefore, the size of magnetic flux concentrator 12 can be further reduced.

[0040] Furthermore, in this embodiment, the Hall element 131 is disposed at a position closer to the opening 12a of the flux concentrator 12 than the first portion 111 in the protruding direction D11 of the second portion 112. With this configuration, the Hall element 131 is disposed in a pass band of most of the magnetic flux φ11 emitted from the flux concentrator 12 on the opening 12a side, thereby improving the sensitivity of measuring the current by the Hall element 131 via the magnetic flux φ11.

[0041] The above-described embodiment merely shows a typical form of the current sensor, but the current sensor is not limited to this and can be implemented in various modifications.

[0042] For example, in the above-described embodiment, a specific fixing method is not specified, and the current sensor 1 is exemplified as an example of a current sensor in which the sensor unit 13 is fixed with the Hall element 131 positioned relative to the bus bar 11. However, the method for fixing the sensor unit in the current sensor is not limited to a specific method, and any fixing method can be adopted.

[0043] In the above-described embodiment, current sensor 1 including bus bar 11 and magnetic flux concentrator plate 12, each of which is a bent member, is exemplified as an example of a current sensor. However, the current sensor is not limited to this. In other words, the bus bar and magnetic flux concentrator plate in the current sensor may be made of machined materials or welded materials made of multiple metal parts, and the specific processing methods for the bus bar and magnetic flux concentrator plate are not important.

[0044] In the above-described embodiment, the current sensor 1 is illustrated as an example of a current sensor, in which the magnetic flux concentrator 12 is disposed near one end edge 111a of the first portion 111 of the L-shaped busbar 11, from which the second portion 112 protrudes. However, the current sensor is not limited to this. The busbar may be, for example, a U-shaped member in a side view, in which a pair of second portions protrude from both end edges of the first portion. Even when an L-shaped busbar is used, the magnetic flux concentrator 12 may be disposed at any position on the first portion in the longitudinal direction of the busbar. However, as described above, by disposing the magnetic flux concentrator 12 near one end edge 111a of the first portion 111 of the L-shaped busbar 11, from which the second portion 112 protrudes, magnetic saturation of the magnetic flux concentrator 12 can be further suppressed.

[0045] In the above-described embodiment, the current sensor 1 is exemplified as an example of a current sensor, in which the magnetic flux concentrator plate 12 is disposed at a position closer to one edge 111a than to the center of the first portion 111 of the L-shaped bus bar 11. However, the current sensor is not limited to this. Even when an L-shaped bus bar is used, the magnetic flux concentrator plate may be disposed, for example, at the center of the first portion. However, as described above, by disposing the magnetic flux concentrator plate 12 at a position closer to one edge 111a than to the center of the first portion 111, magnetic saturation of the magnetic flux concentrator plate 12 can be further suppressed.

[0046] Furthermore, in the above-described embodiment, as an example of a C-shaped magnetic flux concentrator plate, magnetic flux concentrator plate 12 including bottom plate portion 121, a pair of arm plate portions 122, and a pair of top plate portions 123 is exemplified. However, the C-shaped magnetic flux concentrator plate is not limited to this, and may be, for example, a C-shaped magnetic flux concentrator plate formed by cutting out a portion of the peripheral wall of a cylinder. However, as described above, magnetic flux concentrator plate 12 including bottom plate portion 121, a pair of arm plate portions 122, and a pair of top plate portions 123 can further prevent magnetic flux concentrator plate 12 from becoming large.

[0047] In the above-described embodiment, the current sensor 1 in which the Hall element 131 is disposed near the opening 12a of the flux concentrator 12 is exemplified as an example of a current sensor. However, the current sensor is not limited to this, and the Hall element can be disposed at any position between the first portion of the bus bar and the inner surface of the flux concentrator as long as it is possible to detect magnetic flux for current measurement. However, as described above, by disposing the Hall element 131 near the opening 12a of the flux concentrator 12, the current measurement sensitivity can be increased. [Explanation of symbols]

[0048] 1,5 Current sensor 11,61 Busbar 12 Magnetic flux concentrator 12a opening 13 Sensor section 111 Part 1 111a,61a One edge 111b Middle part 111c Other edge 112 Part 2 113 Through hole 121 Bottom plate part 122 Arm plate part 123 Top plate 131 Hall element 132 Sensor board D11 Projection direction D12 Busbar longitudinal direction D13 Busbar width direction D14 Convergence plate longitudinal direction G1,G2 graphs L1 solid line L2 dash-dot line L3 dashed line I current T11 width dimension φ11,φ11a magnetic flux

Claims

1. a bus bar, which is made of a conductive metal and through which a current to be measured flows, and which has a strip-shaped first portion and a strip-shaped second portion protruding from one end edge of the first portion in a protruding direction that intersects with the front and back surfaces of the first portion; a magnetic flux concentrator plate made of a soft magnetic material and having a bent plate shape that surrounds a midway portion of the first portion of the bus bar in the longitudinal direction of the bus bar so that its cross section orthogonal to the longitudinal direction of the bus bar forms a C-shape, and which converges magnetic flux generated by a current when the current flows through the bus bar around the midway portion, the magnetic flux concentrator plate being arranged so that an opening of the C-shape faces the protruding direction; a sensor unit having a Hall element for detecting current, the Hall element being positioned between the opening and the intermediate portion and surrounded by the magnetic flux concentrator plate, and detecting the current via the magnetic flux converged by the magnetic flux concentrator plate; A current sensor comprising:

2. the bus bar is a member formed only by the first portion and the second portion so as to form an L-shape in a side view from a direction perpendicular to the protruding direction and the longitudinal direction of the bus bar, 2. The current sensor according to claim 1, wherein the magnetic flux concentrator plate is disposed at a position closer to the one end edge of the first portion from which the second portion protrudes or the other end edge on the opposite side in the longitudinal direction of the bus bar.

3. 3. The current sensor according to claim 2, wherein the magnetic flux concentrator plate is disposed at a position closer to the one end edge than to a center of the first portion in the longitudinal direction of the bus bar.

4. The magnetic flux concentrator plate is a bottom plate portion extending in a longitudinal direction of a bundling plate along a width direction of the busbar of the first portion, the bottom plate portion being longer than a width dimension of the first portion, so as to face one of the front and rear surfaces of the intermediate portion of the first portion opposite to the side where the Hall element is arranged; a pair of arm plate portions protruding from both end edges of the bottom plate portion in the longitudinal direction of the bundling plate in the protruding direction of the second portion; a pair of top plate portions extending from the protruding end edges of the pair of arm plate portions along the longitudinal direction of the converging plate so as to face the surface of the intermediate portion on which the Hall element is disposed, and spaced apart from each other so that the extending end edges form the opening; 2. The current sensor according to claim 1, further comprising:

5. 2. The current sensor according to claim 1, wherein the Hall element is disposed at a position closer to the opening in the magnetic flux concentrator plate than the first portion in the protruding direction.

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