Electric current sensor

Abstract

An electric current sensor 1 according to the present invention comprises: a substrate 5 which has mounted thereon a bus bar 2 and a magnetic sensor 3 disposed opposite to the bus bar 2, and has an output wiring pattern 4 of the magnetic sensor 3; and a magnetic shield 6 composed of two magnetic shield plates 6a, 6b arranged in parallel in the Z direction. The magnetic shield plates 6a, 6b sandwich the bus bar 2 and the magnetic sensor 3 so that a first magnetic field A is generated between end parts 6E when a high-frequency current flows through the bus bar 2. When viewed along the Z direction, the output wiring pattern 4 has, in a region in which eddy current C is generated by the magnetic field A, an adjustment part 7 extending in a direction including a component in the X direction. The direction of the eddy current C which is generated in the adjustment part 7 by the magnetic field A is the same as the direction of the output current of the magnetic sensor 3 which flows through the adjustment part 7. Accordingly, an electric current sensor which exhibits enhanced responsiveness due to improvement in phase delay of a magnetic field detected by a magnetic detection element and which has excellent high-frequency current measurement accuracy is provided.

Description

Current sensor

[0001] The present invention relates to a current sensor using a magnetic sensor provided with two parallel plate type magnetic shields.

[0002] As a means for controlling the power supply system of various devices in a vehicle or the like, a current sensor that measures a measured current flowing through the device is used. As the current sensor, there is one provided with a magnetic sensor that measures an induced magnetic field based on the measured current flowing through the bus bar. The state of the measured current flowing through the bus bar varies depending on the frequency. In the case of a low-frequency current of about 10 Hz, it flows uniformly throughout the bus bar, whereas in the case of a high-frequency current of about 1 kHz, it flows biased near the surface of the bus bar due to the skin effect. For example, when the bus bar is flat, when the measured current is a high-frequency current, the measured current flows biased near both ends in the width direction due to the skin effect. Therefore, when the measured current is a high-frequency current, there is a problem that a delay occurs in the phase characteristic of the output of the current sensor compared to the low frequency. Therefore, as a current sensor aimed at improving the high-speed responsiveness, there is one in which the magnetic detection element is arranged at a position closer to one magnetic shield than the central position of the magnetic shield (Patent Document 1), or a pair of magnetic shields with the ends of the magnetic shields separated from each other (Patent Document 2), etc. have been proposed.

[0003] Japanese Patent Application Laid-Open No. 2014-6115, Japanese Patent Application Laid-Open No. 2014-25718

[0004] However, the current sensors described in Patent Documents 1 and 2 have a special structure and do not have two parallel plate type magnetic shields. The present invention aims to provide a current sensor having two parallel plate type magnetic shields, which has improved responsiveness by improving the phase delay of the magnetic field detected by the magnetic detection element and is excellent in the measurement accuracy of high-frequency currents.

[0005] As a means to solve the above-mentioned problems, the present invention has the following configuration. The first, second, and third directions are mutually orthogonal directions, and the current sensor comprises a busbar extending in the second direction, a substrate on which a magnetic sensor mounted opposite the busbar is mounted and which has an output wiring pattern for the magnetic sensor, and a magnetic shield consisting of two magnetic shielding plates aligned in the first direction, wherein when a high-frequency current flows through the busbar along the second direction, a first magnet is generated between the ends of the two magnetic shielding plates in the first direction, the busbar and the magnetic sensor are sandwiched in the first direction, and when viewed along the first direction, the output wiring pattern has an adjustment section that extends in a direction including a component of the second direction in a region where eddy currents are generated by the first magnet, and the direction of the eddy currents generated in the adjustment section by the first magnet is equal to the direction of the output current of the magnetic sensor flowing through the adjustment section.

[0006] When a high-frequency current flows through the busbar, a first magnetic field is generated near the ends of the two magnetic shielding plates in a first direction in which the magnetic shielding plates face each other. An adjustment section, which extends to have a component in a second direction, the extension direction of the busbar, is provided in the region where this first magnetic field is generated. Eddy currents are generated in the adjustment section, producing a magnetic field in a direction that cancels out the first magnetic field. When a conductor is placed near the region where this magnetic field is generated, eddy currents are generated in the conductor to produce a magnetic field in a direction that cancels out this magnetic field. Therefore, when the conductor is extended to have a component in the second direction, the extension direction of the busbar, current flows through the conductor. Thus, when an adjustment section, which is a conductor, is placed, current flows through the adjustment section, which can mitigate the phase delay of the output from the magnetic sensor that detects the high-frequency current.

[0007] The adjustment unit may be provided in the magnetic shielding region, which is the area of ​​the substrate sandwiched between the two magnetic shielding plates. The magnetic shielding region has a greater magnetic field strength in the first direction compared to the area not sandwiched between the magnetic shielding plates. Therefore, by providing the adjustment unit in this region, the eddy currents generated in the adjustment unit increase, improving the effect of mitigating the delay in the phase characteristics of the magnetic sensor output when measuring the current value of high-frequency currents.

[0008] When viewed along the first direction, the ends of one magnetic shielding plate in the third direction and the ends of the other magnetic shielding plate in the third direction may be in the same position.

[0009] With the above configuration, the component of the first magnetic field in the first direction, directed from one magnetic shield plate to the other, can be increased near both ends in the third direction. Therefore, by providing an adjustment section in the region between the ends of both magnetic shield plates, the eddy currents generated in the adjustment section increase, improving the effect of mitigating the delay in the phase characteristics of the output of the magnetic sensor that measures the current value of high-frequency currents.

[0010] The adjustment portion may be positioned between the end of the magnetic shield in the third direction and the busbar when viewed along the first direction. In this case, the adjustment portion may be positioned closer to the end than the center line between the end and the busbar when viewed along the first direction.

[0011] Because the current under test flows unevenly across the busbar surface due to the skin effect, if the busbar is a flat plate shape where the third direction (busbar width direction), which is perpendicular to the first and second directions, is larger than the first direction (busbar thickness direction), then large currents flow at both ends in the width direction, generating a relatively large magnetism near the ends of the magnetic shield. Therefore, by placing an adjustment section between the ends of the magnetic shield and the busbar, the eddy currents generated in the adjustment section increase, improving the effect of mitigating the phase delay of the magnetic sensor output.

[0012] When viewed along the first direction, the angle between the extension direction of the adjustment section of the output wiring pattern and the second direction may be 30 degrees or more and 60 degrees or less. By setting the angle between the extension direction of the adjustment section and the extension direction of the busbar within the above range, the delay in the output phase characteristics can be mitigated by the adjustment section without forming a right-angle bend (fold) in the output wiring pattern. Therefore, the impact on electromagnetic compatibility (EMC), such as noise, caused by right-angle bends in the output wiring pattern is suppressed.

[0013] A current sensor comprising a plurality of magnetic shields, each consisting of a plurality of busbars through which a multiphase alternating current flows, a plurality of magnetic sensors mounted one on each of the plurality of busbars facing each other, a substrate having output wiring patterns from each of the plurality of magnetic sensors, and two magnetic shielding plates arranged in a first direction, one on each of the plurality of busbars, wherein when a high-frequency current flows in a second direction, which is the extending direction of the busbars, a first magnet is generated from one of the two magnetic shielding plates toward the other, the two magnetic shielding plates sandwich the busbars and the magnetic sensors in the first direction, and when viewed along the first direction, the output wiring patterns have adjustment portions extending in the second direction to regions where eddy currents are generated by the first magnet.

[0014] By aligning the direction of eddy currents generated in the adjustment section when a high-frequency current flows with the direction of the current flowing through the output wiring pattern, it is possible to mitigate the phase delay of the magnetic sensor's output when measuring high-frequency current values ​​without adding components to the current sensor or performing special processing on the components.

[0015] The plurality of busbars are three busbars through which a three-phase alternating current flows, and the first output wiring pattern from the first magnetic sensor, which is positioned opposite the first busbar to which the first magnetic shield is provided, may have the adjustment section in a region where eddy currents are generated by the first magnetic field from the first magnetic shield that sandwiches the first magnetic sensor to which the output wiring pattern is connected, when viewed along the first direction. By providing the adjustment section in the region where eddy currents are generated by the first magnetic field from the first magnetic shield, the delay in the phase characteristics of the output from the first magnetic sensor can be mitigated when a high-frequency current flows.

[0016] The plurality of busbars are three busbars through which a three-phase alternating current flows, and the first output wiring pattern from the first magnetic sensor, which is positioned opposite the first busbar on which the first magnetic shield is provided, has the adjustment section that extends in a direction including the second direction to a region where the eddy current is generated by the first magnetic field of the second magnetic shield provided on the second busbar other than the first busbar, when viewed along the first direction, and the direction of the eddy current generated in the adjustment section by the first magnetic field may be the same as the direction of the output current of the first magnetic sensor flowing through the adjustment section for a period of more than half of one cycle.

[0017] By providing an adjustment unit in the region where eddy currents are generated by the first magnetic field from the second magnetic shield, the delay in the phase characteristics of the output from the first magnetic sensor can be mitigated.

[0018] A current sensor comprising: a plurality of busbars through which a multiphase alternating current flows; a plurality of magnetic sensors mounted on each of the plurality of busbars, one facing each of the plurality of busbars, and a substrate having output wiring patterns from each of the plurality of magnetic sensors; and a plurality of magnetic shields consisting of two magnetic shield plates arranged in a first direction and provided on each of the plurality of busbars, wherein when a high-frequency current flows in a second direction which is the extending direction of the busbars, a first magnetic field is generated from one of the two magnetic shield plates toward the other, the two magnetic shield plates sandwich the busbars and the magnetic sensors in the first direction, and the output wiring patterns do not have portions extending in a direction that includes a component in the second direction in a region where eddy currents are formed by the magnetic field from one of the two magnetic shield plates toward the other when viewed along the first direction in the magnetic shield. With the above configuration, when measuring the current value of a high-frequency current, the output phase of the first magnetic sensor can be suppressed because the output wiring pattern of the first magnetic sensor is affected by the first magnetic field from the second magnetic shield that sandwiches the second magnetic sensor other than the first magnetic sensor.

[0019] The current sensor of the present invention can suppress the phase delay of the magnetic sensor output when measuring the current value of a high-frequency current by matching the direction of the current flowing to the adjustment section of the output wiring pattern with the direction of the eddy currents generated in the adjustment section when a high-frequency current to be measured flows through the busbar. Therefore, it is possible to provide a current sensor with excellent measurement accuracy for high-frequency currents.

[0020] This is a schematic plan view showing the configuration of the main part of the current sensor according to the first embodiment of the present invention. This is a cross-sectional view of the current sensor in Figure 1 along line AA. This is a schematic cross-sectional view of the current sensor in Figure 1 along line AA, showing the magnetic field formed when a high-frequency current flows through the current sensor in Figure 1. This is a schematic cross-sectional view of the current sensor in Figure 1 along line AA, showing the magnetic field formed when a low-frequency current flows through the current sensor in Figure 1. This is a schematic cross-sectional view showing the current formed near the end of the magnetic shield when a high-frequency current flows through the current sensor in Figure 1. This is a schematic plan view showing the output phase acceleration effect due to eddy currents in the current sensor in Figure 1. This is a schematic plan view showing the output phase delay due to eddy currents in the current sensor in Figure 1. This is a graph showing the simulation result of the relationship between the position in the Z direction and the phase of the magnetic field in the Y direction in the current sensor in Figure 1. This is a schematic perspective view showing the current sensor according to the second embodiment of the present invention. This is a schematic plan view showing the configuration of the main part of the current sensor in Figure 8. This is a cross-sectional view of the current sensor in Figure 9 along line AA. This is a graph showing the simulation results of the relationship between the position of the current sensor in the Y direction and the phase of the magnetic field in the Z direction in Figure 8. This is a graph showing the phase of the current flowing through each busbar in the current sensor in Figure 8. This is a plan view illustrating the effect on the output of high-frequency currents by extending the adjustment section of the output wiring pattern of the magnetic sensor to the vicinity of busbars other than the detection target of the detection sensor. This is a cross-sectional view of the current sensor in Figure 13 along line AA. This is a graph showing the simulation results of the relationship between the position of the current sensor in the Y direction and the phase of the magnetic field in the Z direction in Figure 8. This is a plan view showing the output wiring pattern of the current sensor in Reference Example 1. This is a plan view showing the output wiring pattern of the current sensor in Example 1. This is a plan view showing the output wiring pattern of the current sensor in Example 2. This is a plan view showing the output wiring pattern of the current sensor in Example 3.

[0021] Embodiments of the present invention will be described below with reference to the accompanying drawings. In each drawing, the same components are numbered the same, and descriptions are omitted as appropriate. Reference coordinates are shown in each drawing as appropriate to indicate the positional relationship of each component. In the reference coordinates, the extension direction of the busbar, i.e., the direction of current flow in the portion of the busbar facing the magnetic sensor, is defined as the X direction (second direction), and the width direction of the busbar perpendicular to the X direction is defined as the Y direction (third direction). The direction perpendicular to the X and Y directions is defined as the Z direction (first direction).

[0022] [First Embodiment] Figure 1 is a schematic plan view showing the configuration of the main parts of the current sensor 1 according to this embodiment. Figure 2 is a cross-sectional view of the current sensor 1 along line AA. The current sensor 1 comprises a busbar 2, a magnetic sensor 3, a substrate 5 having an output wiring pattern 4, and a magnetic shield 6.

[0023] Busbar 2 is a conductor through which the current to be measured flows, made of copper, brass, aluminum, or the like, and extends in the X direction. Busbar 2 is not limited to being formed as a plate-like body as a whole; only the portion facing the magnetic sensor 3 may be formed as a plate.

[0024] The magnetic sensor 3 is mounted on the substrate 5 so as to face the main surface of the plate-shaped portion of the busbar 2, and detects the magnetism generated by the current being measured flowing through the busbar 2. The magnetic sensor 3 can be, for example, a Hall element, a giant magnetoresistance element (GMR element), or a tunnel magnetoresistance element (TMR element). The configuration shown in Figures 1 and 2 is an example in which a GMR element with the Y direction as the detection axis is used as the magnetic sensor 3, but when using other magnetic detection elements, the orientation of the detection surface and other aspects should be changed as appropriate. The magnetic sensor 3 may also be a differential type that outputs the difference between the first output and the second output.

[0025] The output wiring pattern 4 is a conductor through which current flows as the magnetic detection output by the magnetic sensor 3, and in the current sensor 1, it is provided on the main surface 5S on the Z2 side of the substrate 5.

[0026] The magnetic shield 6 is a parallel plate type consisting of two flat magnetic shielding plates 6a and 6b aligned in the Z direction. The magnetic shielding plates 6a and 6b can be constructed, for example, by stacking multiple plates of metal of the same shape. The magnetic shield 6 suppresses external magnetic noise to the magnetic sensor 3, thereby improving the measurement accuracy of the current sensor 1.

[0027] Figure 3 is a schematic cross-sectional view along line AA of Figure 1, showing the magnetic field (first magnetic field) A formed when a high-frequency current flows through the current sensor 1 of Figure 1. This figure shows the magnetic field generated when a high-frequency alternating current (AC) of about 1 kHz (referred to as high-frequency current as appropriate) is passed through the busbar 2.

[0028] In the case of high-frequency current, the skin effect makes it difficult for the current to be measured to flow in the center of the cross-section of the busbar 2, so the current to be measured concentrates on the surface of the busbar 2. If the busbar 2 is flat, the current to be measured concentrates at both ends in the Y direction, which is the width direction. For this reason, as shown by the dashed line in the figure, on the Y1 side of the magnetic shield 6, a magnetic field A is generated from near the end 6E of the upper (Z2 side) magnetic shield plate 6b in Figure 3 toward near the Y1 side end 6E of the lower (Z1 side) magnetic shield plate 6a. Also, on the Y2 side, a magnetic field A is generated from near the end 6E of the lower (Z1 side) magnetic shield plate 6a toward near the end 6E of the upper (Z2 side) magnetic shield plate 6b. When a high-frequency current flows through the busbar 2 as the current to be measured, a magnetic field A is applied to the output wiring pattern 4 provided near the end 6E of the magnetic shield plate 6b.

[0029] Figure 4 is a schematic cross-sectional view taken along line AA of Figure 1, showing the magnetic field formed when a low-frequency alternating current flows through the current sensor 1 of Figure 1. This figure shows the magnetic field generated when a low-frequency alternating (AC) current of about 10 Hz (referred to as a low-frequency current as appropriate) is passed through the busbar 2. In the case of a low-frequency current, the current being measured is uniformly distributed within the busbar 2, so an elliptical magnetic field is generated around the busbar 2, and no magnetic field A (see Figure 3) is generated in the region sandwiched between the ends 6E of the magnetic shield 6.

[0030] As shown in Figures 3 and 4, due to the skin effect, the magnetic field formed around the busbar 2 differs depending on the frequency of the current being measured flowing through the busbar 2. Therefore, when the current being measured is a high-frequency current, a delay occurs in the phase characteristics of the output from the magnetic sensor 3.

[0031] Figure 5 is a schematic cross-sectional view showing the eddy currents formed when a high-frequency current flows through the busbar 2. Figure 6A is a schematic plan view showing the effect of eddy currents on accelerating the output phase in the current sensor 1. Figure 6B is a schematic plan view showing the delay of the output phase due to eddy currents in the current sensor 1.

[0032] When the current being measured, flowing from X2 to X1 in the busbar 2, is a high-frequency current, a magnetic field A is generated near the Y1 end 6E of the magnetic shield 6, pointing from top (Z2) to bottom (Z1), as shown by the solid arrow in Figure 5. When a magnetic field A is formed by a high-frequency current, an eddy current C is generated along the circle shown by the thick dashed arrow in the output wiring pattern 4 located near the end 6E, which generates a magnetic field B that is opposite to magnetic field A in order to cancel out magnetic field A.

[0033] If the output wiring pattern 4 extends in the X direction in the same positional relationship as the busbar 2, as shown in Figures 5 and 6A, multiple eddy currents C that generate a magnetic field B will be generated along the output wiring pattern 4. Therefore, as shown in Figure 6A, eddy currents C indicated by the dashed-dotted arrows along the circle that generates the magnetic field B will be generated along the X direction in the output wiring pattern 4.

[0034] As shown in Figure 6A, when viewed along the Z direction, if the output wiring pattern 4 is provided on the Y2 side with reference to the magnetic field B generated by the eddy current C, eddy currents C are generated in the output wiring pattern 4, mainly near the end 6E of the magnetic shield 6. These eddy currents C advance the phase of the output current O flowing through the loop of the output wiring pattern 4 via the output connector, etc.

[0035] As shown in Figure 3, magnetic fields A are generated in opposite directions in the Z direction on both the Y1 (negative) and Y2 (positive) sides. Therefore, when a high-frequency current flows as the current under test through the busbar 2, which has a shape that extends straight along the X axis, regions are formed in which the phase of the magnetic field in the Z direction advances in areas where the distance from the busbar 2 on both the Y1 and Y2 sides is approximately the same.

[0036] As shown in Figure 6B, when the output wiring pattern 4 is placed on the Y1 side with respect to the magnetic field B, the eddy currents C of the magnetic field B delay the phase of the output current O. In other words, when viewed along the Z direction, the effect on the phase of the output current O is reversed depending on whether the output wiring pattern 4 is placed on the Y2 (right) side or the Y1 (left) side of the eddy current C.

[0037] As shown in Figure 6A, when the output wiring pattern 4 is provided on the Y2 side of the magnetic field B, a current D, indicated by the linear dashed arrow, flows through the output wiring pattern 4 as a result of the generation of eddy current C. The flow of current D through the output wiring pattern 4 can advance the phase of the output current O from the magnetic sensor 3. Therefore, the phase delay of the output current O from the magnetic sensor 3, which occurs when the measured current is a high-frequency current and is caused by the phase delay of the induced magnetic field detected by the magnetic sensor 3, can be suppressed (mitigated) by the current D generated by the eddy current C.

[0038] Furthermore, if the output wiring pattern 4 is extended in the Y direction (not shown), the eddy currents C generated in the output wiring pattern 4 by the magnetic field B generated on the X1 side of the output wiring pattern 4 are oriented in the Y1 direction, while the eddy currents C generated in the output wiring pattern 4 by the magnetic field B generated on the X2 side are oriented in the Y2 direction. Since the eddy currents C cancel each other out, no current D is generated, and the output wiring pattern 4 provided between the magnetic shield plates 6a and 6b does not function as an adjustment unit 7.

[0039] The current sensor 1 is positioned such that when a high-frequency current flows through the busbar 2 along the X direction, a magnetic field A is generated between the two magnetic shielding plates 6a and 6b, directed from one to the other. Specifically, the two magnetic shielding plates 6a and 6b sandwich the busbar 2 and the magnetic sensor 3 in the Z direction such that a magnetic field A is generated between the end 6E of magnetic shielding plate 6a and the end 6E of magnetic shielding plate 6b on the same side in the Y direction.

[0040] As shown in Figures 2 to 5, in the current sensor 1, when viewed along the Z direction, both ends 6E in the Y direction of one magnetic shield plate 6a and both ends 6E in the Y direction of the other magnetic shield plate 6b are in the same position. This configuration allows the Z-direction component of the magnetic field A directed from one magnetic shield plate 6a or 6b to the other to be increased in the vicinity of the ends 6E in the Y direction. Therefore, by providing the adjustment section 7 in the region between the ends 6E of the magnetic shield plates 6a and 6b, the eddy current C generated in the adjustment section 7 becomes larger, improving the effect of suppressing the phase delay of the output of the current sensor 1 when measuring the current value of a high-frequency current.

[0041] The output wiring pattern 4 has an adjustment section 7 that extends in a direction that includes a component in a second direction within the region G where eddy currents C are generated by the magnetic field A when viewed along the Z direction. Note that the direction that includes a component in the second direction (X direction) when viewed along the Z direction means a direction that is inclined in the Y direction with respect to the X direction. This direction can be said to be a direction that is not perpendicular to the X direction or parallel to the Y direction. The direction of the eddy currents C generated in the adjustment section 7 by the magnetic field A is equal to the direction of the output current O of the magnetic sensor 3 flowing through the adjustment section 7 (see Figures 1 and 6A).

[0042] The adjustment unit 7 is provided in a magnetic shield region F which is a region sandwiched between two magnetic shield plates 6a and 6b on the substrate 5. More specifically, when viewed along the Z direction, the adjustment unit 7 is provided at a position shifted from the end portion 6E of the magnetic shield plate 6b toward the bus bar 2, between the end portion 6E and the bus bar 2. In the present embodiment, the adjustment unit 7 is proximal to the end portion 6E in the Y direction, that is, the adjustment unit 7 is positioned closer to the end portion 6E than the center line LC between the end portion 6E of the magnetic shield plate 6b and the side surface on the Y1 side of the bus bar 2, and extends parallel to the main surface of the bus bar 2.

[0043] Compared with a region not sandwiched between the magnetic shield plates 6a and 6b, the intensity of the magnetic field A generated in the Z direction is large in the magnetic shield region F. Therefore, by providing the adjustment unit 7 in the magnetic shield region F, the eddy current C generated in the adjustment unit 7 becomes large, and the effect of alleviating the delay in the phase characteristic of the output of the current sensor 1 when measuring the current value of the high-frequency current is improved.

[0044] When the measured current is a high-frequency current, due to the skin effect, the measured current flows biased toward the surface of the bus bar 2. In the case of the flat bus bar 2 whose Y direction (width) is larger than the Z direction (thickness), a large current flows biased to both ends in the width direction, and a relatively large magnetic field A is generated near the end portion 6E of the magnetic shield 6. Therefore, when viewed along the Z direction, by arranging the adjustment unit 7 between the end portion 6E of the magnetic shield plate 6b and the bus bar 2, the eddy current C generated in the adjustment unit 7 becomes large, and the effect of alleviating the delay in the phase characteristic of the output current O of the magnetic sensor 3 is improved.

[0045] FIG. 7 is a graph showing the simulation results of the relationship between the position in the Z direction and the phase of the magnetic field in the Y direction in the current sensor 1 when the measured current flowing through the bus bar 2 is a low-frequency current (10 Hz) and a high-frequency current (1 kHz). On the straight line LZ along the Z axis passing through the center in the Y direction of the bus bar 2, the position of the magnetic sensor 3 was set as the origin in the Z direction, the Z2 direction as minus, and the Z1 direction as plus (see FIG. 2). In the graph of FIG. 7, the position in the Z direction is shown on the horizontal axis, and when the magnetic field in the X direction lags behind the phase of the measured current, it is shown as minus, and when it advances, it is shown as plus. In addition, in the results of FIG. 7 and other simulations, the average value obtained by integrating the entire current sensor 1 is used as the reference (phase 0°).

[0046] From the graph of FIG. 7, it can be seen that at the position of the magnetic sensor 3 (Z = 0), when the measured current is a low-frequency current, there is no phase delay, but when the measured current is a high-frequency current, the phase is delayed by 0.2° (-0.2°). In addition, at the position (-2.5 mm) in the Z direction on the surface (main surface 5S) on the Z2 side of the substrate 5 when the thickness of the substrate 5 is 2.5 mm, the phase delay of the high-frequency current was 0.12° (-0.12°).

[0047] When a high-frequency current flows through the bus bar 2, a magnetic field A is generated in the Z direction near the end portion 6E of the magnetic shield 6. In the region where this magnetic field A is generated, in the adjustment portion 7 extended so as to have a component in the X direction, which is the extending direction of the bus bar 2, an eddy current C is generated that generates a magnetic field in a direction to cancel the generated magnetic field A.

[0048] That is, when the output wiring pattern 4, which is a conductor, is arranged in the region where the magnetic field A is generated near the end portion 6E of the magnetic shield 6, an eddy current C is generated in the output wiring pattern 4 in order to generate a magnetic field B in a direction to cancel this magnetic field A. Therefore, when the output wiring pattern 4 is extended so as to have a component in the X direction, which is the extending direction of the bus bar 2, a current D flows through the output wiring pattern 4 and functions as the adjustment portion 7 (see FIGS. 5 and 6A).

[0049] Therefore, by aligning the direction of the output current O flowing through the adjustment section 7 of the output wiring pattern 4 with the direction of the eddy current C generated in the adjustment section 7, the delay of high-frequency currents can be suppressed. This reduces the delay in the phase characteristics of the output of the magnetic sensor 3 when measuring the current value of high-frequency currents, and provides a current sensor 1 with excellent measurement accuracy for high-frequency currents.

[0050] Furthermore, by providing an adjustment section 7 in a part of the output wiring pattern 4, it becomes possible to improve the phase characteristics of the output of the magnetic sensor 3 without adding any components to the current sensor 1 or performing any special processing on the components.

[0051] [Second Embodiment] Figure 8 is a schematic perspective view showing the current sensor 21 according to this embodiment. In this figure, a part of the case 22 of the current sensor 21 is omitted. Figure 9 is a schematic plan view showing the configuration of the main part of the current sensor 21. Figure 10 is a cross-sectional view of the current sensor 21 of Figure 9 along line AA.

[0052] The current sensor 21 differs from the current sensor 1 of the first embodiment in that it has a configuration that includes multiple busbars 2A to 2C through which multiphase AC current flows. In this embodiment, the case in which three busbars 2A to 2C through which three phase AC current flows will be described, but the number of busbars 2 is not limited to three; for example, there may be two or four or more. Hereafter, if busbars 2A to 2C are not distinguished, they will be referred to as busbar 2 as appropriate. The same applies to the magnetic sensors 3A to 3C, output wiring patterns 4A to 4C, and magnetic shields 6A to 6C.

[0053] Multiple magnetic sensors 3A to 3C are mounted on the circuit board 5, one of each positioned opposite to each of the busbars 2A to 2C, and each of the magnetic sensors 3A to 3C is provided with output wiring patterns 4A to 4C.

[0054] Each of the busbars 2A to 2C is provided with a magnetic shield 6A to 6C consisting of two magnetic shielding plates 6a and 6b aligned in the Z direction. The output wiring patterns 4A to 4C are all arranged so that the current flows in the same direction in the X direction in the portion located in the magnetic shielding region FA to FC sandwiched between the magnetic shielding plates 6a and 6b. In this embodiment, when the current to be measured flows from X2 to X1 in the busbars 2A to 2C, the output current O flowing through the output wiring patterns 4A to 4C is wired so that the direction of the output current O in the X direction is from X1 to X2. That is, the wiring is such that the direction of the output current O in the X direction has a component in the opposite direction to the current to be measured.

[0055] The two magnetic shielding plates 6a and 6b are positioned in the Z direction, sandwiching the busbar 2 and magnetic sensor 3, so that when a high-frequency current flows in the X direction, which is the extension direction of the busbar 2, a magnetic field A is generated from one of the two magnetic shielding plates 6a and 6b toward the other.

[0056] When viewed along the Z direction, the output wiring pattern 4 has an adjustment section 7 that extends in the X direction into region G (see Figure 1) where eddy currents C are generated by the magnetic field A. The output wiring pattern 4 having an adjustment section 7 means that the adjustment section 7 is provided in one of the regions GA to GC within the magnetic shield region FA to FC sandwiched between the magnetic shield plates 6a and 6b of the magnetic shield 6A to 6C.

[0057] The current sensor 21 of this embodiment is equipped with three busbars 2A to 2C, through which a three-phase alternating current flows. The output wiring pattern (first output wiring pattern) 4A from the magnetic sensor (first magnetic sensor) 3A, which is positioned opposite the busbar (first busbar) 2A on which the magnetic shield (first magnetic shield) 6A is provided, is partially located in region GA, and this partially located portion constitutes the adjustment section 7A. In addition, a portion of the output wiring pattern 4C is located in region GC.

[0058] As explained in the first embodiment, by providing an adjustment section 7A extending in the X direction in the output wiring pattern 4A from the magnetic sensor 3A in region GA near busbar 2A, the phase lag of the high-frequency current detected by the magnetic sensor 3A can be mitigated. The same applies when an adjustment section 7C extending in the X direction is provided in region GC near busbar 2C shown in Figure 10 in the output wiring pattern 4C from the magnetic sensor 3C.

[0059] Figure 11 is a graph showing the simulation results of the relationship between the position in the Y direction of the current sensor 1 and the phase of the magnetic field in the Z direction, when the current being measured flowing through the busbar 2C is a low-frequency current (10 Hz) and a high-frequency current (1 kHz). In this graph, the position of the magnetic sensor 3C on the straight line LY along the main surface 5S on the Z2 side of the substrate 5 (the intersection with the straight line LZ) is set as the origin in the Y direction, with the Y1 direction being negative and the Y2 direction being positive (see Figure 10). In the graph shown in this figure, the position in the Y direction is shown on the horizontal axis, and when the magnetic field in the Z direction lags the phase of the current being measured, it is shown as negative, and when it leads, it is shown as positive.

[0060] From the graph shown in Figure 11, it was found that when the measured current is a high-frequency current, the phase of the magnetic field in the Z direction advances in the region where the distance Y from the magnetic sensor 3C on the main surface 5S of the substrate 5 is approximately -14 to -5 mm. From this result, it can be seen that by placing the output wiring pattern 4C of the magnetic sensor 3C in this region, the delay in the measurement phase of the high-frequency current by the magnetic sensor 3C can be mitigated. In other words, by placing the output wiring pattern 4C in the region where the phase of the magnetic field in the Z direction advances, the output wiring pattern 4C functions as an adjustment unit 7.

[0061] In the graph shown in Figure 11, a region where the phase acceleration effect occurs only occurs on the negative (Y1) side of the Y direction, while no region where the phase acceleration effect occurs occurs on the positive (Y2) side. This is thought to be due to the curved shape of the X2 end of the busbar 2C targeted in the simulation in Figure 11, which is bent in the Y1 direction. The phase change due to the shape of the busbar 2C is approximately +0.15° to -0.6°, indicating that the negative effect of delaying the phase of the output current O has a significant influence in that direction.

[0062] Figure 12 is a graph showing the phase of the current flowing through busbars 2A to 2C in the current sensor 21. The figure shows the current waveform of a three-phase AC current, and the measured current flowing through busbars 2A, 2B, and 2C is 120° out of phase with the measured current flowing through the adjacent busbars 2B, 2C, and 2A.

[0063] Focusing on the measured currents flowing through busbars 2A and 2C, the phases of the measured currents are reversed for 2 / 3 of a period. That is, the measured currents flowing through busbars 2A and 2C are the same (either positive or negative) in the 0–60° and 180–240° ranges in Figure 12, and opposite (one positive and the other negative) in the 60–180° and 240–360° ranges.

[0064] Similarly, when focusing on the measured currents flowing through busbars 2A and 2B, the phases of the measured currents are reversed for 2 / 3 of a period. That is, the measured currents flowing through busbars 2A and 2B are the same (either positive or negative) in the 60-120° and 300-360° ranges in Figure 12, and opposite (one positive and the other negative) in the 0-60°, 120-240°, and 300-360° ranges.

[0065] Therefore, when an adjustment unit 7 is provided in the output wiring pattern 4A from the magnetic sensor 3A that detects the magnetic field under measurement of the busbar 2A, whether the eddy current C generated in the adjustment unit 7 when a high-frequency current flows through the busbar 2A suppresses or exacerbates the phase delay of the output of the magnetic sensor 3 depends on whether the adjustment unit 7 is located in the magnetic shielding region FA to FC, and in which direction the output current O flows through the output wiring pattern 4A.

[0066] For example, if the output wiring pattern 4A from magnetic sensor 3A is provided with an adjustment section 7 so that the direction of the output current O of output wiring pattern 4A and output wiring pattern 4C are the same when the current under test flows in the same direction through busbars 2A and 2C in region GC that promotes the output of output wiring pattern 4C from magnetic sensor 3C, then for 2 / 3 of the period, the phase direction of the output will be opposite to that of output wiring pattern 4C. Therefore, when the current under test through busbar 2C is a high-frequency current, the eddy current C caused by busbar 2C will exacerbate the phase lag of the output from magnetic sensor 3A.

[0067] In contrast, when an adjustment section 7 for the output wiring pattern 4A from the magnetic sensor 3A is provided in region GC such that the outputs of output wiring pattern 4A and output wiring pattern 4C are in opposite directions when the current under test flows in the same direction through busbars 2A and 2C, the phase direction of the output of output wiring pattern 4C will be the same for 2 / 3 of the period. Therefore, when the current under test in busbar 2C is a high-frequency current, the eddy current C caused by busbar 2C will suppress the phase lag of the output from the magnetic sensor 3A.

[0068] In the current sensor 21, the adjustment section 7 for the output wiring pattern 4A is not provided in the region that enhances the output of the output wiring pattern 4C from the magnetic sensor 3C. Note that the adjustment section 7C provided in that region is the adjustment section 7 for the output wiring pattern 4C, not the output wiring pattern 4A (see Figures 8 to 10).

[0069] In contrast, when an adjustment section 7 for the output wiring pattern 4A from magnetic sensor 3A is provided in region GC, which promotes the output of the output wiring pattern 4C from magnetic sensor 3C, such that the direction of the output current O of output wiring pattern 4A and output wiring pattern 4C are the same when the measured current flows in the same direction through busbars 2A and 2C, the phase direction of the output of output wiring pattern 4C will be opposite for 2 / 3 of the period. Therefore, by providing the adjustment section 7 for output wiring pattern 4A in region GC, the output from magnetic sensor 3A is delayed.

[0070] As described above, in the current sensor 21 equipped with three busbars 2A to 2C through which three-phase AC current flows, the current under measurement flows in opposite directions for two-thirds of the period of one cycle between busbar 2A and busbars 2B and 2C. Therefore, if the adjustment section 7 of the output wiring pattern 4A from the magnetic sensor 3A, which is positioned opposite busbar 2A, is provided on busbars 2B and 2C, the phase of the output current O will be delayed when the current under measurement is a high-frequency current.

[0071] Therefore, in the current sensor 21, the output wiring pattern 4A from the magnetic sensor 3A, which is positioned opposite the busbar 2A through which the multiphase AC current flows, is arranged so as not to overlap with the magnetic shielding regions FB and FC of the magnetic shields (second magnetic shields) 6B and 6C provided on the magnetic sensors 3B and 3C when viewed along the Z direction. Similarly, the output wiring pattern 4B is also arranged so as not to overlap with the magnetic shielding regions FC and FA sandwiched between the magnetic shields 6C and 6A. Similarly, the output wiring pattern 4C is also arranged so as not to overlap with the magnetic shielding regions FA and FB sandwiched between the magnetic shields 6A and 6B.

[0072] Thus, in the current sensor 21, the output wiring patterns 4A to 4C from the magnetic sensors 3A to 3C, which are positioned opposite each of the busbars 2A to 2C through which the multiphase AC current flows, do not have any portions extending in a direction not perpendicular to the extension direction of the busbars 2A to 2C in the region where eddy currents C are formed when viewed along the Z direction. With this configuration, when measuring the current value of a high-frequency current, it is possible to suppress the delay in the phase characteristics of the output of the magnetic sensors 3A to 3C caused by eddy currents C generated when the current under measurement flows through adjacent busbars 2A to 2C.

[0073] The effect on the output of the high-frequency current detected by the magnetic sensor 3A, caused by extending the adjustment section 7 of the output wiring pattern 4A of the magnetic sensor 3A from the region GA near the busbar 2A, which is the target of detection by the magnetic sensor 3A, to the region GC near the busbar 2C, will be explained below.

[0074] Figure 13 is a plan view of the current sensor 25, in which the adjustment section 7 of the output wiring pattern 4A of the current sensor 25 is provided with an adjustment section 7Aa extending near the busbar 2A which is the detection target of the magnetic sensor 3A to which the output wiring pattern 4A is connected, and an adjustment section 7Ac extending near the other busbars 2C. Figure 14 is a cross-sectional view of the current sensor 25 of Figure 13 along line AA.

[0075] In the examples shown in these figures, the output wiring pattern (first output wiring pattern) 4A from a magnetic sensor (first magnetic sensor) 3A, which is positioned opposite a busbar (first busbar) 2A on which a magnetic shield (first magnetic shield) 6A is provided, has a portion located in region GA, and this portion constitutes an adjustment section 7Aa. In addition, another portion of the output wiring pattern 4A, different from the aforementioned portion, is located in region GC. That is, when viewed along the Z direction, the output wiring pattern 4A has an adjustment section 7Ac that extends in a direction including the X direction as part of the output wiring pattern 4A, into region GC where eddy currents C are generated by the magnetic field A of the magnetic shield 6C provided on the busbar (second busbar) 2C.

[0076] The current sensor 25 has a magnetic shield 6C with an end portion 6CE that generates a magnetic field A when a high-frequency current flows through the busbar 2C. The adjustment portion 7Ac is positioned between the end portion 6CE of the magnetic shield 6C and the busbar 2C when viewed along the Z direction. The direction of the eddy current C generated in the adjustment portion 7Ac, which is provided between the magnetic shield 6C and the busbar 2C due to the magnetic field A, is opposite to the direction of the output current O of the magnetic sensor 3A flowing through the adjustment portion 7Ac. In this respect, it differs from the direction of the eddy current C generated in the adjustment portion 7Aa, which is provided between the magnetic shield 6A and the busbar 2A due to the magnetic field A, which is the same as the direction of the output current O of the magnetic sensor 3A flowing through the adjustment portion 7Aa. Therefore, in the current sensor 25, by providing the adjustment portion 7Ac between the magnetic shield 6C and the busbar 2C in the output wiring pattern 4A of the magnetic sensor 3A, the output of the high-frequency current detected by the magnetic sensor 3A is delayed.

[0077] Figure 15 is a graph showing the simulation results of the relationship between the position in the Y direction of the current sensor 1 and the phase of the magnetic field in the Z direction when a low-frequency current of 10 Hz and a high-frequency current of 1 kHz of three-phase AC are passed through busbars 2A to 2C as the currents to be measured. In this graph, the position of the magnetic sensor 3 on the straight line LY along the main surface 5S on the Z2 side of the substrate 5 (the intersection with the straight line LZ, see Figure 2) is set as the origin in the Y direction, with the Y1 direction being negative and the Y2 direction being positive. In the graph, the position in the Y direction is shown on the horizontal axis, and when the magnetic field in the Z direction lags the phase of the current to be measured, it is shown as negative, and when it leads, it is shown as positive.

[0078] As shown in the figure, when the output wiring pattern 4A from the magnetic sensor 3A facing the busbar 2A is placed in the region sandwiched between the magnetic shield plates 6a and 6b of the magnetic shield 6C provided on the busbar 2C, the induced magnetic field formed by the high-frequency current results in a delay in the measured output current. This is because currents flow in opposite directions through the busbars 2A and 2C for two-thirds of the period of one cycle, which is consistent with the results of the embodiment described later.

[0079] Furthermore, in the graph shown in Figure 15, a region appears where the phase acceleration effect occurs on the positive (Y2) side in the Y direction. This is thought to be because the busbar 2 targeted in the simulation in Figure 15 had a shape in which the end on the X2 side was bent in the Y1 direction (see busbar 2C in Figure 8).

[0080] Furthermore, the output wiring pattern 4A can also be designed such that, for example, when the current to be measured flows in the same direction through busbars 2A and 2C, the output current O flows in opposite directions in the region between magnetic shields 6A and 6C. In this case, by providing the adjustment section 7 in the region between magnetic shields 6C, the phase delay of the output of the high-frequency current from magnetic sensor 3A flowing through the output wiring pattern 4A can be suppressed. The same applies when the adjustment section 7 is provided in the region between magnetic shields 6B in the output wiring pattern 4A. Therefore, by providing the adjustment section 7 in the region between any of the magnetic shields 6A to 6C, the effect of mitigating the phase delay of the output of the high-frequency current can be obtained.

[0081] However, when a three-phase AC current flows through busbars 2A to 2C, the measured current flows in opposite directions through busbars 2A and busbars 2B and 2C for two-thirds of the current cycle. For this reason, in output wiring pattern 4A, providing the adjustment unit 7 in the region sandwiched by the magnetic shield 6A is more effective in mitigating the phase delay of the high-frequency current output.

[0082] Although the case where the adjustment unit 7 is provided in output wiring pattern 4A has been described, the same applies when the adjustment unit 7 is provided in output wiring patterns 4B and 4C.

[0083] (Reference Example 1) Figure 16A is a plan view showing the output wiring patterns 4A to 4C in the current sensor 30 of Reference Example 1. The current sensor 30 has a plurality of busbars 2A to 2C through which a multiphase AC current flows, and magnetic sensors 3A to 3C mounted opposite each of the busbars 2A to 2C. It also has a substrate 5 having output wiring patterns 4A to 4C from each of the magnetic sensors 3A to 3C, and magnetic shields 6A to 6C consisting of two magnetic shielding plates 6a and 6b arranged in the Z direction and provided on each of the plurality of busbars 2A to 2C.

[0084] The magnetic shields 6A to 6C are fundamental components of the current sensor 30, which is necessary not only for detecting high-frequency currents but also for detecting low-frequency currents. The two magnetic shield plates 6a and 6b sandwich the busbar 2 and magnetic sensor 3 in the Z direction. When a high-frequency current that causes the skin effect flows in the X direction, which is the extension direction of the busbar 2, a magnetic field A is generated from one of the two magnetic shield plates 6a and 6b toward the other.

[0085] In the current sensor 30, an output wiring pattern 4A, which outputs the measurement result of the magnetic sensor 3A corresponding to the busbar 2A to the outside, is routed from the Y2 side end of the substrate 5 towards the Y1 side end. Along the route of the output wiring pattern 4A, an adjustment section 7A of the output wiring pattern 4A is extended in the X direction in the area furthest from the busbar 2A between the magnetic shields 6C.

[0086] By arranging an output wiring pattern 4C that outputs the measurement results of the magnetic sensor 3C corresponding to the busbar 2C to the outside in the area of ​​the current sensor 30, when a high-frequency current flows through the busbar 2C, the output of the output wiring pattern 4C is promoted and the delay is suppressed (see Figure 6A).

[0087] However, for two-thirds of the period of one cycle, a current flows through busbar 2A in the opposite direction to that of busbar 2C (see Figure 12). Therefore, when the output wiring pattern 4A is wired in the same direction as output wiring pattern 4C, the portion of output wiring pattern 4A located between the magnetic shields 6C will have its high-frequency current output delayed by the eddy current C generated by the induced magnetic field produced when the measured current flows through busbar 2C.

[0088] (Example 1) Figure 16B is a plan view showing the output wiring patterns 4A to 4C in the current sensor 31 of Example 1. As shown in the figure, in the current sensor 31, the portion of the output wiring pattern 4A that is located between the magnetic shields 6C in the current sensor 30 is moved outside the magnetic shields 6C. As a result, the current sensor 30 is less susceptible to the influence of the magnetic field generated by the three-phase AC current flowing through the busbar 2C, which the output wiring pattern 4A was previously subjected to.

[0089] Therefore, the phase delay caused by the busbar 2C in the output from the magnetic sensor 3A, which measures the magnetic field of the high-frequency current flowing through busbar 2A, is eliminated. As a result, the current sensor 31 has a phase lead in the output of the high-frequency current flowing through the output wiring pattern 4A compared to the current sensor 30.

[0090] The output wiring patterns 4A to 4C of the current sensor 31 do not have any portions that extend in a direction including an X-direction component in the region where eddy currents C are formed by the magnetic field A of the two magnetic shielding plates 6a and 6b of the magnetic shield 6, when viewed along the Z-direction. This configuration differs from that of the current sensor 30. Therefore, the output of the high-frequency current flowing through the output wiring patterns 4A to 4C is not phase-delayed by the high-frequency current flowing through busbars 2 other than the busbar 2 being measured.

[0091] (Example 2) Figure 16C is a plan view showing the output wiring patterns 4A to 4C in the current sensor 32 of Example 2. As shown in the figure, in the current sensor 32, an adjustment section 7A having an X-direction component is provided between the magnetic shields 6A in the output wiring pattern 4A of the current sensor 30. That is, the adjustment section 7A extends in a direction inclined with respect to the extension direction (X-direction) of the busbar 2 (excluding the orthogonal direction). With this configuration, the phase of the current in the output wiring pattern 4A can be advanced by the eddy current C (see Figure 6A) generated in the adjustment section 7A by the magnetic field A formed in the magnetic shield plate 6a. As a result, the current sensor 32 can advance the phase of the output of the high-frequency current flowing through the output wiring pattern 4A compared to the current sensor 30.

[0092] In this embodiment, the current sensor 32 has an extension direction of the adjustment section 7A of the output wiring pattern 4A that is angled R to 30 degrees with respect to the X direction, which is the extension direction of the busbar 2A. By forming an angle R (not bending at a right angle) rather than making the extension direction of the adjustment section 7A parallel to the extension direction of the busbar 2, the current flow in the adjustment section 7A becomes smoother, which is preferable from the viewpoint of countermeasures against EMC (electromagnetic compatibility). The angle R is not particularly limited, but for example, it can be set to about 0 degrees or more and 60 degrees or less. The degree of phase lead / phase lag of the output current O can be adjusted by the size of the angle R.

[0093] Figure 16D is a plan view showing the output wiring patterns 4A to 4C in the current sensor 33 of Embodiment 3. The difference from the current sensor 30 shown in Figure 16A is that, as shown in the same figure, the portion of the output wiring pattern 4A that is located between the magnetic shields 6C in the current sensor 30 is moved outside the magnetic shields 6C in the current sensor 33. In addition, an adjustment section 7A having an X-direction component is provided between the magnetic shields 6A in the output wiring pattern 4A of the current sensor 30. This configuration makes it less susceptible to the influence of the magnetic field generated by the three-phase AC current flowing through the busbar 2C. Furthermore, the eddy current C generated in the adjustment section 7A can advance the phase of the current in the output wiring pattern 4A. As a result, the output phase of the high-frequency current flowing through the output wiring pattern 4A can be advanced more than in Embodiments 1 and 2.

[0094] The following table shows the results of evaluating the phase delay and phase difference when a 1 kHz high-frequency current was applied as the measured current of a three-phase AC current to the busbars 2A to 2C of the current sensors 30 to 33 in Reference Example 1 and Examples 1 to 3. In Reference Example 1 and Examples 1 to 3, measurements were taken by applying a 1 kHz high-frequency current to the same output wiring pattern (a to c) (n=3). As shown in Table 1, in comparison with Reference Example 1, all three Examples 1 to 3 showed improvements in the phase delay and phase delay difference of the output current O. All three Examples 1 to 3 were able to keep the phase delay within -2.00°, and Example 3 was able to keep the phase delay difference within 0.4°.

[0095] According to the measurement results shown in Table 1, the effect of advancing the phase of the output current O compared to Reference Example 1 was +0.3 to 0.4° in Example 1 and +0.3 to 0.4° in Example 2. From these results, it was found that the arrangement of the output wiring pattern has a greater influence on the positive effect of improving the phase delay of the output current O than the shape of the busbar (approximately +0.15°, see Figure 11).

[0096] Therefore, considering the influence on the phase delay of the output current O, designing the position (arrangement) of the output wiring pattern based on the busbar shape is effective in improving the phase delay of the output current O. Furthermore, compared to the busbar shape, which is determined based on the component layout within the inverter, the output wiring pattern offers greater design flexibility, which is also advantageous.

[0097] The present invention is useful, for example, as a current sensor for measuring the current flowing through equipment in order to control a power supply system such as a vehicle equipped with various devices.

[0098] 1 Current sensor 2, 2A-2C Busbar 3, 3A-3C Magnetic sensor 4, 4A-4C Output wiring pattern 5 Circuit board 5S Main surface 6, 6A-6C Magnetic shield 6a, 6b Magnetic shield plate 6E, 6CE End 7, 7A, 7Aa, 7Ac, 7C Adjustment section 21, 25, 30-33 Current sensor 22 Case A, B Magnetic field C Eddy current D Current O Output current F, FA-FC Magnetic shield area G, GA-GC Area LC Centerline LZ Straight line LY Straight line R Angle

Claims

1. A current sensor comprising: a first direction, a second direction, and a third direction which are mutually orthogonal directions; a busbar extending in the second direction; a substrate on which a magnetic sensor mounted opposite the busbar is mounted and which has an output wiring pattern for the magnetic sensor; and a magnetic shield consisting of two magnetic shielding plates aligned in the first direction, wherein when a high-frequency current flows through the busbar along the second direction, a first magnetic field is generated between the ends of the two magnetic shielding plates in the third direction, the two magnetic shielding plates sandwich the busbar and the magnetic sensor in the first direction; and when viewed along the first direction, the output wiring pattern has an adjustment section that extends in a direction including a component of the second direction to a region where eddy currents are generated by the first magnetic field, and the direction of the eddy currents generated in the adjustment section by the first magnetic field is equal to the direction of the output current of the magnetic sensor flowing through the adjustment section.

2. The current sensor according to claim 1, wherein the adjustment unit is provided in a magnetic shielding region which is the region sandwiched between the two magnetic shielding plates on the substrate.

3. The current sensor according to claim 1, wherein, when viewed along the first direction, both ends of one magnetic shielding plate in the third direction and both ends of the other magnetic shielding plate in the third direction are at the same position.

4. The current sensor according to claim 1, wherein the adjustment unit is positioned between the end of the magnetic shield in the third direction and the busbar when viewed along the first direction.

5. The current sensor according to claim 4, wherein the adjustment portion is located closer to the end than the center line between the end and the busbar when viewed along the first direction.

6. The current sensor according to claim 1, wherein, when viewed along the first direction, the angle of the extension direction of the adjustment portion of the output wiring pattern with respect to the second direction is 30 degrees or more and 60 degrees or less.

7. A current sensor comprising: a plurality of busbars through which a multiphase alternating current flows; a plurality of magnetic shields comprising a substrate on which a plurality of magnetic sensors are mounted, one facing each of the plurality of busbars, and having output wiring patterns from each of the plurality of magnetic sensors; and two magnetic shielding plates arranged in a first direction, one of which is provided on each of the plurality of busbars, wherein when a high-frequency current flows in a second direction, which is the direction in which the busbars extend, a first magnetic field is generated from one of the two magnetic shielding plates toward the other, the two magnetic shielding plates sandwich the busbars and the magnetic sensors in the first direction, and when viewed along the first direction, the output wiring patterns have an adjustment portion extending in the second direction to a region in which eddy currents are generated by the first magnetic field.

8. The current sensor according to claim 7, wherein the plurality of busbars are three busbars through which a three-phase alternating current flows, and the first output wiring pattern from a first magnetic sensor positioned opposite a first busbar to which a first magnetic shield is provided has the adjustment section in a region where the eddy current is generated by the first magnetic field from the first magnetic shield that sandwiches the first magnetic sensor to which the output wiring pattern is connected, when viewed along the first direction.

9. The current sensor according to claim 7, wherein the plurality of busbars are three busbars through which a three-phase alternating current flows, and the first output wiring pattern from a first magnetic sensor positioned opposite a first busbar on which a first magnetic shield is provided has an adjustment section that, when viewed along the first direction, extends in a direction including the second direction to a region where eddy currents are generated by the first magnetic field of a second magnetic shield provided on a second busbar other than the first busbar, and the direction of the eddy currents generated in the adjustment section by the first magnetic field is the same as the direction of the output current of the first magnetic sensor flowing through the adjustment section for a period of more than half of one cycle.

10. A current sensor comprising: a plurality of busbars through which a multiphase alternating current flows; a plurality of magnetic sensors mounted on each of the plurality of busbars, one facing each other, and having output wiring patterns from each of the plurality of magnetic sensors; and a plurality of magnetic shields consisting of two magnetic shielding plates arranged in a first direction and provided on each of the plurality of busbars, wherein the two magnetic shielding plates sandwich the busbars and the magnetic sensors in the first direction such that when a high-frequency current flows in the second direction which is the extending direction of the busbars, a first magnetic field is generated from one of the two magnetic shielding plates toward the other; and the output wiring patterns, when viewed along the first direction in the magnetic shield, do not have portions extending in a direction that includes a component in the second direction in a region where eddy currents are formed by the magnetic field from one of the two magnetic shielding plates toward the other.

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