Current Sensor

Abstract

An electric current sensor (1) has four or more even numbers of magnetosensitive elements (20a-20j). Said even numbers of magnetosensitive elements include: magnetosensitive elements constituting first pairs that are each axisymmetic with respect to a first straight line (Z); and magnetosensitive elements constituting second pairs that are each axisymmetic with respect to a second straight line (X). One of the magnetosensitive elements constituting each of the first pairs has a sensitivity axis that coincides with: a sensitivity axis obtained by mirror-inverting the sensitivity axis of the other of the magnetosensitive elements with respect to the first straight line (Z) and by reversing the direction of the mirror-inverted sensitivity axis; or a sensitivity axis obtained by mirror-inverting the sensitivity axis of the other magnetosensitive element with respect to the first straight line. One of the magnetosensitive elements constituting each of the second pairs has a sensitivity axis that coincides with: a sensitivity axis obtained by mirror-inverting the sensitivity axis of the other of the magnetosensitive elements constituting the second pair with respect to the second straight line and by reversing the direction of the mirror-inverted sensitivity axis; or a sensitivity axis obtained by mirror-inverting the sensitivity axis of the other magnetosensitive element with respect to the second straight line. One or more pairs of magnetosensitive elements have sensitivity axes that are inclined with respect to both of the first straight line (Z) and the second straight line (X).

Description

[Technical Field]

[0001] The present disclosure relates to a current sensor. [Background technology]

[0002] A current sensor has been proposed that uses multiple magnetic sensing elements to detect the magnetic field created in the surrounding space by the current flowing through the current path under test, and calculates the current value based on the detected magnetic field (see, for example, Patent Document 1). In this type of current sensor, the magnetic field created at the position of each magnetic sensing element by the current flowing through the current path under test varies depending on the relative positional relationship between the current path under test and the magnetic sensing elements, so the measured current value also varies depending on the relative positional deviation between the current path under test and the magnetic sensing elements. Therefore, the current sensor is required to have high tolerance (i.e., high robustness) to relative positional deviation between the current path under test and the magnetic sensing elements. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6232080 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional current sensor has a problem in that it is not robust enough to withstand relative positional deviation between the current path to be measured and the magnetic sensing element.

[0005] An object of the present disclosure is to provide a current sensor that is highly robust against misalignment of a current path to be measured. [Means for solving the problem]

[0006] The current sensor of the present disclosure has an even number of magnetic sensitive elements, four or more, arranged side by side in a reference plane orthogonal to a reference line extending in a predetermined reference direction, the even number of magnetic sensitive elements including a first pair of magnetic sensitive elements arranged at positions that are line-symmetrical with respect to a first straight line that passes through an intersection of the reference line and the reference plane and is orthogonal to the reference line, the even number of magnetic sensitive elements including a second pair of magnetic sensitive elements arranged at positions that are line-symmetrical with respect to a second straight line that is orthogonal to both the reference line and the first straight line and passes through the intersection, and each of the sensitivity axes of one of the magnetic sensitive elements of the first pair is aligned with the sensitivity axis of the other of the magnetic sensitive elements of the first pair relative to the first straight line. The sensitivity axis of one of the first pair of magnetic sensitive elements coincides with the sensitivity axis obtained by mirroring and inverting the sensitivity axis of the other of the first pair of magnetic sensitive elements with respect to the first line, or the sensitivity axis obtained by mirroring and inverting the sensitivity axis of the other of the second pair of magnetic sensitive elements with respect to the first line, and each of the sensitivity axes of one of the second pair of magnetic sensitive elements coincides with the sensitivity axis obtained by mirroring and inverting the sensitivity axis of the other of the second pair of magnetic sensitive elements with respect to the second line, or the sensitivity axis obtained by mirroring and inverting the sensitivity axis of the other of the second pair of magnetic sensitive elements with respect to the second line, and the sensitivity axes of one or more pairs of magnetic sensitive elements among the even number of magnetic sensitive elements are inclined with respect to both the first line and the second line. [Effects of the Invention]

[0007] The current sensor of the present disclosure has high robustness, and therefore, when used, the current value can be measured accurately. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a circuit breaker (including a breaker body and a terminal cover) including a current sensor according to a first embodiment. [Figure 2] FIG. 2 is a plan view showing the main part of the circuit breaker shown in FIG. [Figure 3] FIG. 2 is a side view showing the main part of the circuit breaker shown in FIG. [Figure 4] 2 is a perspective view showing a circuit breaker body and a board inside a terminal cover according to the first embodiment. FIG. [Figure 5] 3 is a diagram showing the arrangement of magnetic sensitive elements and sensitivity axes of the current sensor according to the first embodiment. FIG. [Figure 6] 1 is a block diagram showing a configuration of a current sensor according to a first embodiment. [Figure 7] FIG. 7 is a block diagram showing an arithmetic circuit shown in FIG. 6. [Figure 8] 6 is a diagram showing the arrangement and sensitivity axes of the magnetic sensitive elements of the second magnetic sensitive element group in the current sensor shown in FIG. 5. FIG. [Figure 9] 9 is a diagram showing the parameter dependency of the current measurement error of the second group of magnetically sensitive elements shown in FIG. 8. FIG. [Figure 10] 6 is a diagram showing the arrangement and sensitivity axes of the magnetic sensitive elements of the first magnetic sensitive element group in the current sensor shown in FIG. 5. FIG. [Figure 11] 11 is a diagram showing the parameter dependency (when w1 / w0=0.9) of the current measurement error of the first group of magneto-sensitive elements shown in FIG. 10. FIG. [Figure 12] 11 is a diagram showing the parameter dependency (when w1 / w0=1.2) of the current measurement error of the first group of magneto-sensitive elements shown in FIG. 10. FIG. [Figure 13] 11 is a diagram showing the parameter dependency (when w1 / w0=1.5) of the current measurement error of the first group of magneto-sensitive elements shown in FIG. 10. FIG. [Figure 14] 6A and 6B are diagrams illustrating the principle of cancellation of a disturbance magnetic field in the current sensor shown in FIG. 5. [Figure 15] 10 is a diagram showing the arrangement of magnetic sensitive elements and sensitivity axes of the current sensor according to the second embodiment. FIG. [Figure 16] FIG. 10 is a block diagram showing a configuration of a current sensor according to a second embodiment. [Figure 17] FIG. 17 is a block diagram showing the arithmetic circuit shown in FIG. 16. [Figure 18] 16A and 16B are diagrams illustrating the principle of cancellation of a disturbance magnetic field in the current sensor shown in FIG. 15. [Figure 19] 10 is a diagram showing the arrangement of magnetic sensitive elements and sensitivity axes of a current sensor according to a third embodiment. FIG. [Figure 20]FIG. 10 is a block diagram showing a configuration of a current sensor according to a third embodiment. [Figure 21] FIG. 21 is a block diagram showing the arithmetic circuit shown in FIG. 20. [Figure 22] 10 is a diagram showing the arrangement of magnetic sensitive elements and sensitivity axes of a current sensor according to a fourth embodiment. FIG. [Figure 23] FIG. 10 is a block diagram showing a configuration of a current sensor according to a fourth embodiment. [Figure 24] FIG. 24 is a block diagram showing the arithmetic circuit shown in FIG. 23. [Figure 25] 10 is a diagram showing the arrangement of magnetic sensitive elements and sensitivity axes of a current sensor according to a fifth embodiment. FIG. [Figure 26] FIG. 10 is a block diagram showing the configuration of a current sensor according to a fifth embodiment. [Figure 27] FIG. 27 is a block diagram showing the arithmetic circuit shown in FIG. 26. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, current sensors according to embodiments will be described with reference to the drawings. The following embodiments are merely examples, and the embodiments can be appropriately combined and modified.

[0010] 1. First embodiment 1-1 Circuit breaker FIG. 1 is a perspective view showing a circuit breaker 2 (including a circuit breaker body 3 and a terminal cover 4) including a current sensor according to a first embodiment. FIG. 2 is a plan view showing the main parts of the circuit breaker 2 shown in FIG. 1. FIG. 3 is a side view showing the main parts of the circuit breaker shown in FIG. 1. FIG. 4 is a perspective view showing the circuit breaker body 3 and a board 40 inside the terminal cover 4. FIGS. 1 to 4 show coordinate axes of an xyz Cartesian coordinate system showing the appearance of the circuit breaker 2. The x-axis is the coordinate axis in the horizontal direction of the circuit breaker 2, the y-axis is the coordinate axis in the vertical direction of the circuit breaker 2, and the z-axis is the coordinate axis in the depth direction (or thickness direction) of the circuit breaker 2.

[0011] The circuit breaker 2 includes a circuit breaker body 3 and a terminal cover 4. The circuit breaker body 3 includes three-phase current paths 11 (U phase), 12 (V phase), and 13 (W phase) and an operating handle 6 that a user uses to turn the current paths on and off (i.e., conduct and interrupt). The circuit breaker body 3 has a front surface 7 and a bottom surface 8, and the terminal cover 4 is attached to the front surface 7 of the circuit breaker body 3. The terminal cover 4 includes an end portion 4a located outside (on the -x side) of the current path 11, a line-to-line portion 4b located between the current paths 11 and 12, a line-to-line portion 4c located between the current paths 12 and 13, and an end portion 4d located outside (on the +x side) of the current path 13. As shown in FIG. 3 , the terminal cover 4 includes a substrate 40 on which multiple magnetically sensitive elements (i.e., magnetic sensors) constituting a current sensor are mounted. The substrate 40 has a shape that matches the shape of the housing 5. The substrate 40 has an end region 41 which is the region outside (-x side) the current path 11, an inter-line region 42 which is the region between the current paths 11 and 12, an inter-line region 43 which is the region between the current paths 12 and 13, and an end region 44 which is the region outside (+x side) the current path 13.

[0012] The terminal cover 4 has a function of covering the terminals of the current paths 11, 12, and 13 of the circuit breaker body 3. The terminal cover 4 has a function of measuring the current value of the current flowing through the current path, the voltage of the current path, the amount of power supplied through the current path, and the like. A measurement unit that measures values ​​indicating the current flowing through the current path is provided inside the housing 5 of the terminal cover 4. For example, in the first embodiment, the measurement unit includes two current sensors 1. The two current sensors 1 measure a U-phase current that is a current flowing through the U-phase current path 11 and a W-phase current that is a current flowing through the W-phase current path 13. The V-phase current that is a current flowing through the V-phase current path 12 is calculated based on the measured values ​​of the U-phase current and the W-phase current. The measurement unit also includes multiple voltage sensors (not shown) that measure the voltages of the current paths 11, 12, and 13, and calculates the power supplied to the load device through the circuit breaker 2 based on the measured voltage values ​​and the measured current values ​​by the two current sensors 1. In the first embodiment, the circuit breaker 2 only needs to have at least one current sensor 1, and does not necessarily have to have two current sensors 1.

[0013] An even number of magnetic sensing elements, four or more, are mounted on the substrate 40 of the terminal cover 4. The magnetic sensing elements are elements that can detect magnetic fields, and there is no limitation on the type. For example, the magnetic sensing elements are magnetoresistive effect elements and Hall elements. The magnetoresistive effect elements are, for example, giant magnetoresistance (GMR) elements, tunnel magnetoresistance (TMR) elements, or anisotropic magnetoresistance (AMR) elements.

[0014] 1-2 Current sensor 1 FIG. 5 is a diagram illustrating the arrangement of the magnetically sensitive elements and the sensitivity axes of the current sensor 1 according to the first embodiment. In FIG. 5, a reference line Y is a straight line parallel to the y-axis in FIGS. 1 to 4. A current path to be measured 10, which is a current line to be measured (e.g., one of current paths 11, 12, or 13), is arranged on the reference line Y so as to extend in a reference direction parallel to the y-axis. In reality, there may be a positional deviation between the position of the current path to be measured 10 and the position of the reference line Y. Also, in FIG. 5, a first line Z intersects with the reference line Y at an intersection point and is a straight line parallel to the z-axis in FIGS. 1 to 4. Also, a second line X intersects both the reference line Y and the first line Z and is a straight line parallel to the x-axis in FIGS. 1 to 4. The X-, Y-, and Z-axes are coordinate axes of an XYZ Cartesian coordinate system used to explain the arrangement of the multiple magnetically sensitive elements and the orientation of the sensitivity axes.

[0015] The current sensor 1 according to the first embodiment has an even number of magnetically sensitive elements, four or more, arranged side by side in a reference plane XZ perpendicular to a reference line Y extending in a predetermined reference direction (i.e., the Y-axis direction). In the example of FIG. 5, the current sensor 1 has ten magnetically sensitive elements 20a, 20b, 20c, 20d, 20e, 20f, 20g, 20h, 20i, and 20j (also referred to as "magnetically sensitive elements 20" or "magnetically sensitive elements 20a to 20j"). In the first embodiment, the magnetically sensitive elements 20a to 20j include a row of magnetically sensitive elements 20g, 20c, 20a, 20d, and 20h arranged parallel to the Z-axis, and a row of magnetically sensitive elements 20j, 20f, 20b, 20e, and 20i. Although two rows of magnetically sensitive elements are shown in FIG. 5, the arrangement of the magnetically sensitive elements is not limited to two rows.

[0016] The magnetic sensitive elements 20a, 20b, 20c, 20d, 20e, 20f, 20g, 20h, 20i, and 20j each have a sensitivity axis 30a, 30b, 30c, 30d, 30e, 30f, 30g, 30h, 30i, and 30j (also referred to as "sensitivity axis 30" or "sensitivity axes 30a to 30j"). The magnetic sensitive elements 20 detect a magnetic field in the direction of the sensitivity axis 30 (the direction of the arrow in FIG. 5, also referred to as the "magnetic sensing direction") at the position of the magnetic sensitive element 20, and output a signal having a value corresponding to the strength of the magnetic field in the direction of the sensitivity axis 30. There is no limit to the number of magnetic sensitive elements 20, as long as it is an even number of four or more. To improve measurement accuracy, it is desirable to increase the even number of magnetic sensitive elements 20. To simplify the structure, it is desirable to reduce the even number of magnetic sensitive elements 20.

[0017] The magnetic sensitive elements 20a to 20j include a first pair of magnetic sensitive elements arranged at positions that are line symmetrical with respect to a first line Z that passes through the intersection of the reference line Y and the reference plane XZ and is perpendicular to the reference line Y. The first pair is a pair of magnetic sensitive elements that are arranged at positions that are line symmetrical with respect to the first line Z. In the example of FIG. 5, the magnetic sensitive elements that make up the first pair are magnetic sensitive elements 20a and 20b, magnetic sensitive elements 20c and 20f, magnetic sensitive elements 20d and 20e, magnetic sensitive elements 20g and 20j, and magnetic sensitive elements 20h and 20i. However, the magnetic sensitive elements that make up the first pair are not limited to the example of FIG. 5.

[0018] Furthermore, the magnetic sensitive elements 20a to 20j include a second pair of magnetic sensitive elements arranged at positions that are line-symmetrical with respect to a second line X that is perpendicular to both the reference line Y and the first line Z and passes through the intersection point. In the example of FIG. 5, the second pair of magnetic sensitive elements are magnetic sensitive elements 20c and 20d, magnetic sensitive elements 20f and 20e, magnetic sensitive elements 20g and 20h, and magnetic sensitive elements 20j and 20i. In this way, the magnetic sensitive elements 20c to 20j, which are part of the magnetic sensitive elements 20a to 20j, form the first pair of magnetic sensitive elements and also form the second pair of magnetic sensitive elements. However, the second pair of magnetic sensitive elements is not limited to the example of FIG. 5.

[0019] The sensitivity axis of one of the first pair of magnetic sensitive elements coincides with the sensitivity axis obtained by mirror-reflecting and inverting (rotating 180 degrees) the sensitivity axis of the other of the first pair of magnetic sensitive elements with respect to the first straight line Z. For example, the sensitivity axes 30a, 30c, 30d, 30g, 30h of the magnetic sensitive elements 20a, 20c, 20d, 20g, 20h of one of the first pair of magnetic sensitive elements coincide with the sensitivity axis obtained by mirror-reflecting and inverting the sensitivity axes 30b, 30f, 30e, 30j, 30i of the other of the first pair of magnetic sensitive elements 20b, 20f, 20e, 20j, 20i with respect to the first straight line Z. In other words, the sensitivity axes 30a, 30c, 30d, 30g, and 30h, which are mirror images of the sensitivity axes 30a, 30c, 30d, 30g, and 30h with respect to the first line Z, are antiparallel to the sensitivity axes 30b, 30f, 30e, 30j, and 30i. "Antiparallel" means that the sensitivity axes are parallel to each other and have opposite directions (i.e., sensitivity directions).

[0020] The sensitivity axis of one of the second pair of magnetic sensitive elements coincides with the sensitivity axis obtained by mirroring and inverting the sensitivity axis of the other of the second pair of magnetic sensitive elements with respect to the second line X. For example, the sensitivity axes 30c, 30f, 30g, and 30j of one of the second pair of magnetic sensitive elements 20c, 20f, 20g, and 20j coincide with the sensitivity axis obtained by mirroring and inverting the sensitivity axes 30d, 30e, 30h, and 30i of the other of the second pair of magnetic sensitive elements 20d, 20e, 20h, and 20i with respect to the second line X. In other words, the sensitivity axes obtained by mirroring the sensitivity axes 30c, 30f, 30g, and 30j with respect to the second line X are antiparallel to the sensitivity axes 30d, 30e, 30h, and 30i.

[0021] The sensitivity axes of one or more pairs of magnetic sensing elements among the even number of magnetic sensing elements are inclined with respect to both the first line Z and the second line X. In the example of Fig. 5, the sensitivity axes 30c, 30d, 30e, 30f, 30g, 30h, 30i, and 30j of the magnetic sensing elements 20c, 20d, 20e, 20f, 20g, 20h, 20i, and 20j are inclined with respect to both the first line Z and the second line X.

[0022] 5, the magnetic sensitive elements 20a to 20j include a first magnetic sensitive element group 21 and a second magnetic sensitive element group 22 that is arranged farther from the second straight line X than the first magnetic sensitive element group 21. The first magnetic sensitive element group 21 includes four magnetic sensitive elements 20c, 20d, 20e, and 20f that are arranged farther from the second straight line X, and two magnetic sensitive elements 20a and 20b that are arranged on the second straight line X. The second magnetic sensitive element group 22 includes four magnetic sensitive elements 20g, 20h, 20i, and 20j.

[0023] 6 is a block diagram showing the configuration of the current sensor 1 according to the first embodiment. The current sensor 1 outputs an output voltage V a ,V b ,V c ,V d ,V e ,V f ,V g ,V h ,V i ,V j The arithmetic circuit 200 further includes an arithmetic circuit 200 that calculates a value indicating the current flowing through the current path to be measured 10, which is a conductor arranged on the reference line Y so as to extend in the reference direction (i.e., a direction parallel to the reference line Y), based on the above. The arithmetic circuit 200 is provided on, for example, the substrate 40. The arithmetic circuit 200 is configured by, for example, a semiconductor integrated circuit, a microprocessor, etc. The arithmetic circuit 200 may be arranged anywhere. The arithmetic circuit 200 may be an external observation device or an external computer. The arithmetic circuit 200 calculates an output voltage V, which is the output of the even number of magnetic sensing elements 20a to 20j. a ,V b ,V c ,V d ,V e ,V f ,V g ,V h ,V i ,V j Based on the weighted sum of the above, a value indicating the current flowing through the current path 10 to be measured, which is arranged on the reference line Y so as to extend in the reference direction, is calculated, and a voltage signal V corresponding to the instantaneous value of the current flowing through the current path 10 to be measured is generated. det Output.

[0024] Fig. 7 is a block diagram showing the arithmetic circuit 200 shown in Fig. 6. The arithmetic circuit 200 calculates the output voltage V a ,V b ,V c ,V d ,V e ,V f ,V g ,V h ,V i ,V j The output voltage V is calculated by adding weights using weighting coefficients w0, w1, and w2. a ,V b ,V c ,V d ,V e ,V f ,V g ,V h ,V i ,V j and use this as the voltage signal V det The voltage signal V det corresponds to the instantaneous value of the current flowing through the current path 10 to be measured and is given by the following equation (1). In this way, the outputs of at least one of the first and second pairs of magnetic sensing elements are multiplied by the same weighting coefficient. In this case, as clearly shown in equation (1), the block diagram of FIG. 7 may be modified so that the outputs of at least one of the first and second pairs of magnetic sensing elements are summed, multiplied by a common weighting coefficient, and finally summed. On the other hand, if there is variation in the sensitivity of the magnetic sensing elements 20a to 20j, the sensitivity may be corrected by incorporating a correction coefficient into the weighting coefficient to make the net sensitivity uniform. In this case, the value of the weighting coefficient may be different for each of the magnetic sensing elements 20a to 20j.

[0025]

number

[0026] 1-3 Second magnetic sensing element group 22 Fig. 8 is a diagram showing the arrangement of the magnetic sensitive elements 20g, 20h, 20i, and 20j of the second magnetic sensitive element group 22 and the sensitivity axes 30g, 30h, 30i, and 30j in the current sensor 1 shown in Fig. 5. In an XZ coordinate system in which the second line X and the first line Z are the coordinate axes (X axis and Z axis), the coordinates of the positions of the magnetic sensitive elements 20g, 20h, 20i, and 20j are expressed as (x0, z2), (x0, -z2), (-x0, -z2), and (-x0, z2). In addition, the weighting coefficient of the magnetic sensitive elements 20g, 20h, 20i, and 20j is expressed as w2. In addition, the orientation of the sensitive axes 30g, 30h, 30i, and 30j of the magnetic sensing elements 20g, 20h, 20i, and 20j, that is, the angle θ of the magnetic sensing direction when the +Z direction is taken as 0° and the rotation direction when the right-handed screw advances in the +Y direction is taken as positive. g ,θ h ,θ i ,θ j are θ2, -θ2, θ2+180°, and -θ2-180°, respectively. Also, the output voltages of the magnetic sensing elements 20g, 20h, 20i, and 20j are V g ,V h ,V i ,V j In this case, the weighted sum V2 of the outputs of the magnetic sensing elements 20g, 20h, 20i, and 20j is given by the following equation (2).

[0027]

number

[0028] Fig. 9 is a diagram showing the parameter dependency of the current measurement error of the second magnetic sensing element group 22 shown in Fig. 8. Here, the design parameters that determine the characteristics of the current sensor 1 are z2 / x0 and θ2. The weighting coefficient w2 is a value that is determined when combining with the first magnetic sensing element group 21, and therefore does not need to be included in the design parameters of the second magnetic sensing element group 22.

[0029] In general, when the current path 10 to be measured is displaced (i.e., shifted) from its reference position on the reference line Y (i.e., the coordinates (0,0) of the origin in the XZ coordinate system), the value of the weighted sum V2 of the outputs of the magnetic sensing elements changes depending on the displacement (i.e., deviation) of the current path 10 to be measured from the reference line Y. The displacement of the current path 10 to be measured is represented by the vector r e and the vector r e =(x e ,z e ) depending on

[0030] Vector r indicates the deviation from the reference line Y, which is the reference position of the current path 10 to be measured. e =(x e ,z e ) is the weighted sum V2(x e ,z e It is desirable to select the values ​​of the design parameters z2 / x0 and θ2 so that the fluctuation of θ2 is sufficiently small. e ≦δx and -δz≦z e The weighted sum V2(x e ,z e ) is defined as the maximum value E2(δx, δz) of the error rate, and is used as an index for selecting the parameter z2 / x0, which is the aspect ratio, and θ2 [°], which is the angle indicating the direction of the sensitivity axis. In this case, the maximum value E2(δx, δz) of the error rate of the weighted sum is given by the following equation (3).

[0031]

number

[0032] FIG. 9 shows the dependence of E2(δx, δz) on the parameters z2 / x0 and θ2 when δx = δz = 0.3x0. Note that advancing θ2 by 180° (i.e., θ2 + 180°) or delaying θ2 by 180° (i.e., θ2 - 180°) is equivalent and results in the same E2(δx, δz). As can be seen from FIG. 9, the value of θ2 that minimizes the maximum weighted sum error rate E2(δx, δz) varies depending on the value of parameter z2 / x0. That is, the larger the value of z2 / x0, the smaller the value of θ2 that minimizes E2(δx, δz). Therefore, E2(δx, δz) can be reduced by appropriately selecting the value of θ2 according to the desired aspect ratio z2 / x0. We can also see that the minimum value of E2(δx, δz) that can be achieved by adjusting the value of θ2 becomes smaller as the value of z2 / x0 becomes larger. In the example in Figure 9, z2 / x0 = 2.25, and the maximum value of the weighted sum error rate E2(δx, δz) becomes minimum when θ2 = approximately 70°.

[0033] As an index for selecting the parameters z2 / x0 and θ2, the value E2′(δx, δz) given by the following equation (4) may be used instead of E2(δx, δz) given by equation (3).

[0034]

number

[0035] 1-4 First magnetic sensing element group 21 Fig. 10 is a diagram showing the arrangement of the magnetic sensing elements 20a, 20b, 20c, 20d, 20e, and 20f of the first magnetic sensing element group 21 and the sensitivity axes 30a, 30b, 30c, 30d, 30e, and 30f in the current sensor 1 shown in Fig. 5. In the XZ coordinate system, the coordinates of the positions of the magnetic sensing elements 20a, 20b, 20c, 20d, 20e, and 20f are expressed as (x0, 0), (-x0, 0), (x0, z1), (x0, -z1), (-x0, -z1), and (-x0, z1). Furthermore, the weighting coefficient of the magnetic sensing elements 20a and 20b is expressed as w0, and the weighting coefficient of the magnetic sensing elements 20c, 20d, 20e, and 20f is expressed as w1. The orientation of the sensitivity axes 30a, 30b, 30c, 30d, 30e, and 30f of the magnetic sensing elements 20a, 20b, 20c, 20d, 20e, and 20f, that is, the angle θ of the magnetic sensing direction when the +Z direction is taken as 0° and the rotation direction when the right-handed screw advances in the +Y direction is taken as positive. a ,θ b ,θ c ,θ d ,θ e ,θ f are 180°, 0°, θ1, -θ1, θ1+180°, and -θ1-180°, respectively. The output voltages of the magnetic sensing elements 20a, 20b, 20c, 20d, 20e, and 20f are V a ,V b ,V c ,V d ,V e ,V f In this case, the weighted sum V1 of the outputs of the magnetic sensing elements 20a, 20b, 20c, 20d, 20e, and 20f is given by the following equation (5).

[0036]

number

[0037] The design parameters that determine the characteristics of the current sensor 1 are z1 / x0, w1 / w0, and θ1. Fig. 11 is a diagram showing the parameter dependency of the current measurement error of the first magnetic sensing element group 21 shown in Fig. 10 (when w1 / w0=0.9). Fig. 12 is a diagram showing the parameter dependency of the current measurement error of the first magnetic sensing element group 21 shown in Fig. 10 (when w1 / w0=1.2). Fig. 13 is a diagram showing the parameter dependency of the current measurement error of the first magnetic sensing element group 21 shown in Fig. 10 (when w1 / w0=1.5).

[0038] In general, when the current path 10 to be measured is displaced (i.e., shifted) from its reference position on the reference line Y (i.e., the coordinates (0,0) of the origin in the XZ coordinate system), the value of the weighted sum V1 of the outputs of the magnetic sensing elements is changed depending on the displacement (i.e., shift) of the current path 10 to be measured from the reference line Y (vector r e =(x e ,z e ) and varies depending on ).

[0039] Vector r indicates the deviation from the reference line Y, which is the reference position of the current path 10 to be measured. e =(x e ,z e ) is the weighted sum V1(x e ,z e It is desirable to select the values ​​of the design parameters z1 / x0 (i.e., aspect ratio), w1 / w0, and θ1 so that the fluctuation of δx is sufficiently small. e ≦δx and -δz≦z e The weighted sum V1(x e ,z e ) is defined as the maximum value E1(δx, δz) of the error rate and used as an index for selecting the parameters z1 / x0, w1 / w0 and θ1. The maximum value E1(δx, δz) of the weighted sum error rate is given by the following equation (6).

[0040]

number

[0041] Figures 11 to 13 show the dependence of E1(δx, δz) on the parameters z1 / x0 and θ1 when δx = δz = 0.3x0, corresponding to the cases of w1 / w0 = 0.9, w1 / w0 = 1.2, and w1 / w0 = 1.5, respectively. These figures reveal that the combination of z1 / x0 and θ1 values ​​that minimizes the maximum weighted sum error rate E1(δx, δz) varies depending on the selection of parameter w1 / w0. That is, the larger the value of w1 / w0, the larger the value of z1 / x0 and the smaller the value of θ1 that achieves a small E1(δx, δz). In the example of Figure 11 (w1 / w0 = 0.9), z1 / x0 = 0.5, and θ1 = approximately 240°, the maximum weighted sum error rate E1(δx, δz) is minimized. In the example shown in Figure 12 (w1 / w0 = 1.2), z1 / x0 = 0.6, and the maximum weighted sum error rate E1(δx, δz) is minimized when θ1 = 220°. In the example shown in Figure 13 (w1 / w0 = 1.5), z1 / x0 = 0.7, and the maximum weighted sum error rate E1(δx, δz) is minimized when θ1 = 200°. It can also be seen that the minimum value of E1(δx, δz) obtained by appropriately selecting the combination of z1 / x0 and θ1 is almost independent of the value of the parameter w1 / w0. Thus, just as there are many selectable values ​​of the parameter w1 / w0, there are countless combinations of w1 / w0, z1 / x0, and θ1 that minimize the value of E1(δx, δz).

[0042] As an index for selecting the parameters z1 / x0, w1 / w0 and θ1, the value E1'(δx, δz) given by the following equation (7) may be used instead of E1(δx, δz) given by equation (6).

[0043]

number

[0044] 1-5 Sensitivity axis direction In the first quadrant of the XZ coordinate system (shown in FIGS. 8 and 10) with the second straight line X as the X-axis, the first straight line Z as the Z-axis, and the intersection of the X-axis and the Z-axis as the origin, it is desirable that the angles θ1 and θ2 satisfy the following conditions:

[0045] The angle θ1 of the sensitivity axis 30c of the magnetic sensing element 20c of the first magnetic sensing element group 21 in the first quadrant from the +Z direction is 180°≦θ1≦270°, and the angle θ2 of the sensitivity axis 30g of the magnetic sensing element 20g of the second magnetic sensing element group 22 in the first quadrant from the +Z direction is 60°≦θ2≦120°. By specifying the angle in the first quadrant, the directions of the sensitivity axes in the second, third, and fourth quadrants are determined.

[0046] Note that a similar effect can be obtained in a configuration in which the sensitivity axes 30a to 30j of all of the magnetic sensitive elements 20a to 20j constituting the current sensor 1 are rotated 180°. In this case, the angle θ1 of the sensitivity axis 30c of the magnetic sensitive element 20c of the first magnetic sensitive element group 21 in the first quadrant from the +Z direction is 0°≦θ1≦90°, and the angle θ2 of the sensitivity axis 30g of the magnetic sensitive element 20g of the second magnetic sensitive element group 22 in the first quadrant from the +Z direction is 240°≦θ2≦300°.

[0047] Furthermore, a similar effect can be obtained by rotating one or more of the sensitivity axes 30a-30j of the magnetic sensitive elements 20a-20j constituting the current sensor 1 by 180° and adding a negative weighting coefficient to the output of each of the elements. In this case, the angle θ1 of the sensitivity axis 30c of the magnetic sensitive element 20c of the first magnetic sensitive element group 21 in the first quadrant from the +Z direction is 180°≦θ1≦270° or 0°≦θ1≦90°, and the angle θ2 of the sensitivity axis 30g of the magnetic sensitive element 20g of the second magnetic sensitive element group 22 in the first quadrant from the +Z direction is 60°≦θ2≦120° or 240°≦θ2≦300°.

[0048] 1-6. Stray magnetic fields Fig. 14 is a diagram showing the principle of cancellation of a disturbance magnetic field in the current sensor 1 shown in Fig. 5. Fig. 14 shows an example in which an adjacent current path 14 parallel to the reference line Y is located in the +X direction of the current path 10 to be measured, and an adjacent current path 15 parallel to the reference line Y is located in the +Z direction of the current path 10 to be measured. Fig. 14 shows how a disturbance magnetic field 104 is generated by the current flowing through the adjacent current path 14, and a disturbance magnetic field 105 is generated by the current flowing through the adjacent current path 15.

[0049] In Figure 14, the magnetically sensitive elements that are most affected by the disturbance magnetic field 104 generated by the adjacent current path 14 are the five magnetically sensitive elements 20a, 20c, 20d, 20g, and 20h that are closest to the adjacent current path 14. This is because the magnitude of the magnetic field is inversely proportional to the distance from the current path. The disturbance magnetic field 104 has a positive contribution to the magnetically sensitive elements 20a, 20c, and 20d that belong to the first magnetically sensitive element group 21, which increases the detected value, while it has a negative contribution to the magnetically sensitive elements 20g and 20h that belong to the second magnetically sensitive element group 22, which decreases the detected value. In this way, by selecting a combination of the first magnetically sensitive element group 21 and the second magnetically sensitive element group 22 and adjusting the weighting coefficient w2 / w0, the contribution of the first magnetically sensitive element group 21 from the adjacent current path 14 and the contribution of the second magnetically sensitive element group 22 from the adjacent current path 14 can be made to cancel each other out when a weighted sum is calculated. Therefore, in the first embodiment, the influence of the disturbance magnetic field from the adjacent current path 14 can be reduced.

[0050] In FIG. 14, the magnetic sensing elements that are significantly affected by the disturbance magnetic field 105 generated by the adjacent current path 15 are the four magnetic sensing elements 20c, 20f, 20g, and 20j that are close to the adjacent current path 15. The disturbance magnetic field 105 makes a negative contribution to the magnetic sensing elements 20c and 20f that belong to the first magnetic sensing element group 21, which contributes to reducing the detected value, while it makes a positive contribution to the magnetic sensing elements 20g and 20j that belong to the second magnetic sensing element group 22, which contributes to increasing the detected value. In this way, the contribution that the first magnetic sensing element group 21 receives from the adjacent current path 15 and the contribution that the second magnetic sensing element group 22 receives from the adjacent current path 15 can be made to cancel each other out. In other words, by selecting a combination of the first and second magnetic sensing element groups and further adjusting the weighting coefficient w2 / w0, the voltage signal V det This reduces the influence of the disturbance magnetic field from the adjacent current path 15 that appears in the -X direction. Due to the symmetry of the magnetic sensing element group, the influence of the disturbance magnetic field can also be reduced for the adjacent current path in the -X direction and the adjacent current path in the -Z direction using the same principle.

[0051] 1-7 Effects (Effect 1) According to the current sensor 1 of embodiment 1, the first group of magnetically sensitive elements 21 and the second group of magnetically sensitive elements 22 can be designed independently so as to reduce fluctuations in the measured current value caused by misalignment of the current path to be measured 10. Therefore, even in the current sensor 1 in which the first group of magnetically sensitive elements 21 and the second group of magnetically sensitive elements 22 are combined, fluctuations in the measured current value caused by misalignment of the current path to be measured 10 can be reduced.

[0052] (Effect 2) Since the first group of magnetically sensitive elements 21 and the second group of magnetically sensitive elements 22 each have a degree of freedom in parameter selection, the aspect ratios (i.e., z1 / x0, z2 / x0) of the combined first group of magnetically sensitive elements 21 and second group of magnetically sensitive elements 22 can be flexibly changed depending on the installation target.

[0053] (Effect 3) As shown in FIG. 14, the contribution of the disturbance magnetic field caused by the adjacent current paths 14 and 15 can be canceled between the first magnetic sensing element group 21 and the second magnetic sensing element group 22. Therefore, the voltage signal V det This can reduce the influence of the disturbance magnetic field that appears in the

[0054] 2. Second Embodiment 15 is a diagram showing the arrangement of magnetic sensitive elements and sensitivity axes of a current sensor 1a according to embodiment 2. The current sensor 1a according to embodiment 2 differs from the current sensor 1 according to embodiment 1 in that no magnetic sensitive elements are arranged on the second line X and the number of magnetic sensitive elements is eight.

[0055] In the example of Fig. 15, the current sensor 1a has eight magnetically sensitive elements 20a, 20b, 20c, 20d, 20e, 20f, 20g, and 20h (also referred to as "magnetically sensitive element 20" or "magnetically sensitive elements 20a to 20h"). In the second embodiment, the magnetically sensitive elements 20a to 20h include a row of magnetically sensitive elements 20e, 20a, 20b, and 20f and a row of magnetically sensitive elements 20h, 20d, 20c, and 20g that are aligned parallel to the Z axis. Although Fig. 15 shows two rows of magnetically sensitive elements, the arrangement of the magnetically sensitive elements is not limited to two rows.

[0056] The magnetic sensitive elements 20a to 20h have sensitivity axes 30a to 30h (also referred to as "sensitivity axes 30"). The magnetic sensitive elements 20 detect a magnetic field in the direction of the sensitivity axes 30 (the direction of the arrows in FIG. 15) at the position of the magnetic sensitive element 20, and output a signal having a value corresponding to the strength of the magnetic field in the direction of the sensitivity axes 30.

[0057] The magnetic sensitive elements 20a to 20h include a first pair of magnetic sensitive elements arranged at positions that are line-symmetric with respect to a first line Z that passes through the intersection of the reference line Y and the reference plane XZ and is perpendicular to the reference line Y. The first pair is a pair of magnetic sensitive elements that are arranged at positions that are line-symmetric with respect to the first line Z. In the example of FIG. 15, the first pair of magnetic sensitive elements are magnetic sensitive elements 20a and 20d, magnetic sensitive elements 20b and 20c, magnetic sensitive elements 20e and 20h, and magnetic sensitive elements 20f and 20g. However, the first pair of magnetic sensitive elements is not limited to the example of FIG. 15.

[0058] Furthermore, the magnetic sensitive elements 20a to 20h include a second pair of magnetic sensitive elements arranged at positions that are line-symmetrical with respect to a second line X that is perpendicular to both the reference line Y and the first line Z and passes through the intersection point. In the example of FIG. 15, the second pair of magnetic sensitive elements are magnetic sensitive elements 20a and 20b, magnetic sensitive elements 20e and 20f, magnetic sensitive elements 20d and 20c, and magnetic sensitive elements 20h and 20g. In this way, the magnetic sensitive elements 20a to 20h form a first pair of magnetic sensitive elements as well as a second pair of magnetic sensitive elements. However, the second pair of magnetic sensitive elements is not limited to the example of FIG. 15.

[0059] The sensitivity axis of one of the first pair of magnetic sensitive elements coincides with the sensitivity axis obtained by mirroring and inverting the sensitivity axis of the other of the first pair of magnetic sensitive elements with respect to the first straight line Z. For example, the sensitivity axes 30a, 30b, 30e, 30f of one of the first pair of magnetic sensitive elements 20a, 20b, 20e, 20f coincide with the sensitivity axis obtained by mirroring and inverting the sensitivity axes 30d, 30c, 30h, 30g of the other of the first pair of magnetic sensitive elements 20d, 20c, 20h, 20g with respect to the first straight line Z. In other words, the sensitivity axes obtained by mirroring the sensitivity axes 30a, 30b, 30e, 30f with respect to the first straight line Z and the sensitivity axes 30d, 30c, 30h, 30g are antiparallel to each other.

[0060] The sensitivity axis of one of the second pair of magnetic sensitive elements coincides with the sensitivity axis obtained by mirroring and inverting the sensitivity axis of the other of the second pair of magnetic sensitive elements with respect to the second line X. For example, the sensitivity axes 30a, 30d, 30e, 30h of one of the second pair of magnetic sensitive elements 20a, 20d, 20e, 20h coincide with the sensitivity axis obtained by mirroring and inverting the sensitivity axes 30b, 30c, 30f, 30g of the other of the second pair of magnetic sensitive elements 20b, 20c, 20f, 20g with respect to the second line X. In other words, the sensitivity axes obtained by mirroring and inverting the sensitivity axes 30a, 30d, 30e, 30h with respect to the second line X are antiparallel to the sensitivity axes 30b, 30c, 30f, 30g.

[0061] The sensitivity axes of one or more pairs of magnetic sensing elements among the even number of magnetic sensing elements are inclined with respect to both the first straight line Z and the second straight line X. In the example of Fig. 15, the sensitivity axes 30a, 30b, 30c, 30d, 30e, 30f, 30g, and 30h of the magnetic sensing elements 20a, 20b, 20c, 20d, 20e, 20f, 20g, and 20h are inclined with respect to both the first straight line Z and the second straight line X.

[0062] 15, the magnetic-sensitive elements 20a to 20h include a first magnetic-sensitive element group 21 and a second magnetic-sensitive element group 22 that is disposed farther from the second line X than the first magnetic-sensitive element group 21. The first magnetic-sensitive element group 21 includes four magnetic-sensitive elements 20a, 20b, 20c, and 20d that are disposed farther from the second line X. The second magnetic-sensitive element group 22 includes four magnetic-sensitive elements 20e, 20f, 20g, and 20h. The first magnetic-sensitive element group 21 and the second magnetic-sensitive element group 22 according to the second embodiment are both equivalent to the second magnetic-sensitive element group 22 according to the first embodiment shown in FIG. 8. That is, the current sensor 1a according to the second embodiment corresponds to a combination of two second magnetic-sensitive element groups 22 according to the first embodiment.

[0063] 16 is a block diagram showing the configuration of a current sensor 1a according to embodiment 2. The current sensor 1a outputs an output voltage V a ,V b ,V c ,V d ,V e ,V f ,V g ,V h The calculation circuit 200a further includes a calculation circuit 200a for calculating a value indicating a current flowing through the current path 10 to be measured, which is arranged on the reference line Y so as to extend in the reference direction (i.e., a direction parallel to the reference line Y), based on the output voltage V a ,V b ,V c ,V d ,V e ,V f ,V g ,V hBased on the weighted sum of the above, a value indicating the current flowing through the current path 10 to be measured, which is arranged on the reference line Y so as to extend in the reference direction, is calculated, and a voltage signal V corresponding to the instantaneous value of the current flowing through the current path 10 to be measured is generated. det Output.

[0064] Fig. 17 is a block diagram showing the arithmetic circuit 200a shown in Fig. 16. The arithmetic circuit 200a calculates the output voltage V a ,V b ,V c ,V d ,V e ,V f ,V g ,V h The output voltage V is calculated by adding weighted sums using weighting coefficients w1 and w2. a ,V b ,V c ,V d ,V e ,V f ,V g ,V h and use this as the voltage signal V det The voltage signal V det corresponds to the instantaneous value of the current flowing through the current path 10 to be measured and is given by the following equation (8). In this way, the outputs of at least one of the first and second pairs of magnetic sensing elements are multiplied by the same weighting coefficient. In this case, as clearly shown in equation (8), the block diagram of FIG. 17 may be modified so that the outputs of at least one of the first and second pairs of magnetic sensing elements are summed, multiplied by a common weighting coefficient, and finally summed. On the other hand, if there is variation in the sensitivity of the magnetic sensing elements 20a to 20h, the sensitivity may be corrected by incorporating a correction coefficient into the weighting coefficient to make the net sensitivity uniform. In this case, the value of the weighting coefficient may be different for each of the magnetic sensing elements 20a to 20h.

[0065]

number

[0066] Figure 18 is a diagram showing the principle of cancellation of a disturbance magnetic field in the current sensor 1a shown in Figure 15. Figure 18 shows an example in which an adjacent current path 14 parallel to the reference line Y is located in the +X direction of the current path 10 to be measured, and an adjacent current path 15 parallel to the reference line Y is located in the +Z direction of the current path 10 to be measured. Figure 18 shows how a disturbance magnetic field 104 is generated by the current flowing through the adjacent current path 14, and a disturbance magnetic field 105 is generated by the current flowing through the adjacent current path 15.

[0067] In FIG. 18 , the magnetically sensitive elements that are significantly affected by the disturbance magnetic field 104 generated by the adjacent current path 14 are the four magnetically sensitive elements 20a, 20b, 20e, and 20f located close to the adjacent current path 14. The disturbance magnetic field 104 has a positive contribution to the magnetically sensitive elements 20a and 20b belonging to the first magnetically sensitive element group 21, which increases the detection value, while it has a negative contribution to the magnetically sensitive elements 20e and 20f belonging to the second magnetically sensitive element group 22, which decreases the detection value. In this way, by selecting a combination of the first magnetically sensitive element group 21 and the second magnetically sensitive element group 22 and further adjusting the weighting coefficient w2 / w1, the contribution of the first magnetically sensitive element group 21 from the adjacent current path 14 and the contribution of the second magnetically sensitive element group 22 from the adjacent current path 14 can be canceled out when a weighted sum is calculated. Therefore, in the second embodiment, the influence of the disturbance magnetic field from the adjacent current path 14 can be reduced.

[0068] In FIG. 18, the magnetic sensing elements that are significantly affected by the disturbance magnetic field 105 generated by the adjacent current path 15 are the four magnetic sensing elements 20e, 20h, 20a, and 20d that are close to the adjacent current path 15. The disturbance magnetic field 105 makes a negative contribution to the magnetic sensing elements 20a and 20d that belong to the first magnetic sensing element group 21, which contributes to reducing the detected value, whereas it makes a positive contribution to the magnetic sensing elements 20e and 20h that belong to the second magnetic sensing element group 22, which contributes to increasing the detected value. In this way, the contribution that the first magnetic sensing element group 21 receives from the adjacent current path 15 and the contribution that the second magnetic sensing element group 22 receives from the adjacent current path 15 can be made to cancel each other out. In other words, by selecting a combination of the first and second magnetic sensing element groups and further adjusting the weighting coefficients w2 / w1, the voltage signal V that indicates the weighted sum can be detThis reduces the influence of the disturbance magnetic field from the adjacent current path 15 that appears in the -X direction. Due to the symmetry of the magnetic sensing element group, the influence of the disturbance magnetic field can also be reduced for the adjacent current path in the -X direction and the adjacent current path in the -Z direction using the same principle.

[0069] According to the current sensor 1a of the second embodiment, it is possible to obtain the same effects (Effect 1) to (Effect 3) as in the case of the first embodiment. Furthermore, according to the current sensor 1a, it is possible to simplify the configuration of the current sensor compared to the case of the first embodiment. In other respects, the second embodiment is similar to the first embodiment.

[0070] 3. Third Embodiment FIG. 19 is a diagram showing the arrangement and sensitivity axes of the magnetic sensitive elements of a current sensor 1b according to the third embodiment. The current sensor 1b according to the third embodiment differs from the current sensor 1 according to the first embodiment in that it does not include the second magnetic sensitive element group 22 and has six magnetic sensitive elements. That is, the current sensor 1b according to the third embodiment is composed of the first magnetic sensitive element group 21 of the current sensor 1 according to the first embodiment. The sensitivity axes of one or more pairs of magnetic sensitive elements among these magnetic sensitive elements are inclined with respect to both the first line Z and the second line X. In the example of FIG. 19, the sensitivity axes 30c, 30d, 30e, and 30f of the magnetic sensitive elements 20c, 20d, 20e, and 20f are inclined with respect to both the first line Z and the second line X. In other respects, the third embodiment is similar to the first embodiment.

[0071] 20 is a block diagram showing the configuration of a current sensor 1b according to embodiment 3. The current sensor 1b outputs an output voltage V a ,V b ,V c ,V d ,V e ,V f The calculation circuit 200b further includes an arithmetic circuit for calculating a value indicating a current flowing through the current path 10 to be measured, which is arranged on the reference line Y so as to extend in the reference direction, based on the output voltage V a ,V b,V c ,V d ,V e ,V f Based on the weighted sum of the above, a value indicating the current flowing through the current path 10 to be measured, which is arranged on the reference line Y so as to extend in the reference direction, is calculated, and a voltage signal V corresponding to the instantaneous value of the current flowing through the current path 10 to be measured is generated. det Output.

[0072] Fig. 21 is a block diagram showing the arithmetic circuit 200b shown in Fig. 20. The arithmetic circuit 200b calculates the output voltage V a ,V b ,V c ,V d ,V e ,V f The output voltage V is calculated by adding weighted sums using weighting coefficients w0 and w1. a ,V b ,V c ,V d ,V e ,V f and use this as the voltage signal V det The voltage signal V det corresponds to the instantaneous value of the current flowing through the current path 10 to be measured and is given by the following equation (9). In this way, the outputs of at least one of the first and second pairs of magnetic sensing elements are multiplied by the same weighting coefficient. In this case, as clearly shown in equation (9), the block diagram of FIG. 21 may be modified so that the outputs of at least one of the first and second pairs of magnetic sensing elements are summed, multiplied by a common weighting coefficient, and finally summed. On the other hand, if there is variation in the sensitivity of the magnetic sensing elements 20a to 20f, the sensitivity may be corrected by incorporating a correction coefficient into the weighting coefficient to make the net sensitivity uniform. In this case, the value of the weighting coefficient may be different for each of the magnetic sensing elements 20a to 20f.

[0073]

number

[0074] Current sensor 1b according to embodiment 3 can be designed to reduce fluctuations in the measured current value due to misalignment of current path 10 to be measured, as in embodiment 1. Therefore, fluctuations in the measured current value due to misalignment of current path 10 to be measured can be reduced. Furthermore, current sensor 1b can simplify the configuration of the current sensor compared to embodiment 1. Current sensor 1b can be used when the influence of external magnetic disturbances is sufficiently small.

[0075] 4. Fourth embodiment FIG. 22 is a diagram showing the arrangement and sensitivity axes of the magnetic sensitive elements of a current sensor 1c according to the fourth embodiment. The current sensor 1c according to the fourth embodiment differs from the current sensor 1 according to the first embodiment in that it does not include the first magnetic sensitive element group 21 and has four magnetic sensitive elements. That is, the current sensor 1c according to the fourth embodiment is configured with the second magnetic sensitive element group 22 of the current sensor 1 according to the first embodiment. The sensitivity axes of one or more pairs of magnetic sensitive elements among these magnetic sensitive elements are inclined with respect to both the first line Z and the second line X. In the example of FIG. 22, the sensitivity axes 30g, 30h, 30i, and 30j of the magnetic sensitive elements 20g, 20h, 20i, and 20j are inclined with respect to both the first line Z and the second line X. In other respects, the fourth embodiment is similar to the first embodiment.

[0076] 23 is a block diagram showing the configuration of a current sensor 1c according to embodiment 4. The current sensor 1c detects an output voltage V g ,V h ,V i ,V j The calculation circuit 200c further includes an arithmetic circuit for calculating a value indicating a current flowing through the current path to be measured 10, which is arranged on the reference line Y so as to extend in the reference direction, based on the output voltage V g ,V h ,V i ,V jBased on the weighted sum of the above, a value indicating the current flowing through the current path 10 to be measured, which is arranged on the reference line Y so as to extend in the reference direction, is calculated, and a voltage signal V corresponding to the instantaneous value of the current flowing through the current path 10 to be measured is generated. det Output.

[0077] Fig. 24 is a block diagram showing the arithmetic circuit 200c shown in Fig. 23. The arithmetic circuit 200c calculates the output voltage V g ,V h ,V i ,V j The output voltage V g ,V h ,V i ,V j and use this as the voltage signal V det The voltage signal V det corresponds to the instantaneous value of the current flowing through the current path 10 under measurement and is given by the following equation (10). In this way, the outputs of at least one of the first and second pairs of magnetic sensing elements are multiplied by the same weighting coefficient. In this case, as clearly shown in equation (10), the block diagram of FIG. 24 may be modified so that the outputs of at least one of the first and second pairs of magnetic sensing elements are summed and then multiplied by a common weighting coefficient. Furthermore, the value of the weighting coefficient w2 may be selected arbitrarily, and therefore, if the sensitivity of the magnetic sensing elements is equal, the multiplier may be omitted. On the other hand, if there is variation in the sensitivity of the magnetic sensing elements 20g to 20j, a correction coefficient for aligning the net sensitivity may be incorporated into the weighting coefficient to correct the sensitivity. In this case, the value of the weighting coefficient may be different for each of the magnetic sensing elements 20g to 20j.

[0078]

number

[0079] According to the current sensor 1c of the fourth embodiment, similar to the first embodiment, it is possible to design the current sensor 1c so that the fluctuation of the measured current value caused by the positional deviation of the current path 10 to be measured is small. Therefore, it is possible to suppress the fluctuation of the measured current value caused by the positional deviation of the current path 10 to be small. Furthermore, according to the current sensor 1c, it is possible to simplify the configuration of the current sensor more than in the first embodiment. The current sensor 1c can be used when the influence of the disturbance magnetic field is sufficiently small.

[0080] 5. Fifth embodiment Fig. 25 is a diagram showing the arrangement of magnetically sensitive elements and sensitivity axes of a current sensor 1d according to embodiment 5. In Fig. 25, parts that are the same as or correspond to parts shown in Fig. 5 (embodiment 1) are assigned the same reference numerals as those shown in Fig. 5. The current sensor 1d according to embodiment 5 differs from the current sensor 1 according to embodiment 1 in that the orientations of the sensitivity axes 30a', 30c', 30d', 30g', and 30h' of the magnetically sensitive elements 20a, 20c, 20d, 20g, and 20h are opposite to the orientations of the sensitivity axes 30a, 30c, 30d, 30g, and 30h of the magnetically sensitive elements 20a, 20c, 20d, 20g, and 20h in the current sensor 1 according to embodiment 1. That is, the sensitivity axes 30a', 30c', 30d', 30g', and 30h' in FIG. 25 and the sensitivity axes 30a, 30c, 30d, 30g, and 30h in FIG. 5 (first embodiment) are in an anti-parallel relationship.

[0081] In other words, in the fifth embodiment, the sensitivity axis of one of the first pair of magnetic sensitive elements (20c and 20f, ...) coincides with the sensitivity axis of the other of the first pair of magnetic sensitive elements (20c and 20f, ...) which is a mirror image of the sensitivity axis of the other of the first pair of magnetic sensitive elements (20c and 20f, ...) with respect to the first straight line Z. Also, in the fifth embodiment, the sensitivity axis of one of the second pair of magnetic sensitive elements (20c and 20d, ...) coincides with the sensitivity axis obtained by mirroring and inverting the sensitivity axis of the other of the second pair of magnetic sensitive elements (20c and 20d, ...) with respect to the second straight line X.

[0082] The sensitivity axes of one or more pairs of magnetic sensing elements among the even number of magnetic sensing elements are inclined with respect to both the first straight line Z and the second straight line X. In the example of Fig. 25, the sensitivity axes 30c', 30d', 30e, 30f, 30g', 30h', 30i, 30j of the magnetic sensing elements 20c, 20d, 20e, 20f, 20g, 20h, 20i, 20j are inclined with respect to both the first straight line Z and the second straight line X.

[0083] FIG. 26 is a block diagram showing the configuration of a current sensor 1d according to the fifth embodiment. The current sensor 1d outputs an output voltage V a ,V b ,V c ,V d ,V e ,V f ,V g ,V h ,V i ,V j The calculation circuit 200d further includes an arithmetic circuit 200d for calculating a value indicating the current flowing through the current path 10 to be measured, which is arranged on the reference line Y so as to extend in the reference direction, based on the output voltage V a ,V b ,V c ,V d ,V e ,V f ,V g ,V h ,V i ,V j Based on the weighted sum of the above, a value indicating the current flowing through the current path 10 to be measured, which is arranged on the reference line Y so as to extend in the reference direction, is calculated, and a voltage signal V corresponding to the instantaneous value of the current flowing through the current path 10 to be measured is generated. det Output.

[0084] Fig. 27 is a block diagram showing the arithmetic circuit 200d shown in Fig. 26. The arithmetic circuit 200d calculates the output voltage V a ,V b ,V c ,V d ,V e ,V f ,V g ,Vh ,V i ,V j The output voltage V is calculated by weighting and adding the weights w0, w1, w2, -w0, -w1, and -w2. a ,V b ,V c ,V d ,V e ,V f ,V g ,V h ,V i ,V j and use this as the voltage signal V det The voltage signal V det corresponds to the instantaneous value of the current flowing through the current path 10 under measurement and is given by the following equation (11). In this way, the outputs of at least one of the first and second pairs of magnetic sensing elements are multiplied by weighting coefficients of the same magnitude. In this case, the block diagram of FIG. 27 may be modified so that the outputs of at least one of the first and second pairs of magnetic sensing elements that are multiplied by the same weighting coefficient (positive or negative) are summed, then multiplied by a common weighting coefficient, and finally summed. On the other hand, if there is variation in the sensitivity of the magnetic sensing elements 20a to 20j, the sensitivity may be corrected by incorporating a correction coefficient into the weighting coefficient to make the net sensitivity uniform. In this case, the magnitude of the weighting coefficient may be different for each of the magnetic sensing elements 20a to 20j.

[0085]

number

[0086] According to the current sensor 1d of the fifth embodiment, it is possible to obtain the same effects (Effect 1) to (Effect 3) as in the case of the first embodiment. Except for the above, the fifth embodiment is similar to the first embodiment. [Explanation of symbols]

[0087] 1, 1a to 1d current sensor, 2 circuit breaker, 3 breaker body, 4 terminal cover, 5 housing, 10 current path to be measured, 11, 12, 13 current path, 20a to 20j magnetic sensing element, 21 first magnetic sensing element group, 22 second magnetic sensing element group, 30a to 30j sensitivity axis, 30a', 30c', 30d', 30g', 30h' sensitivity axis, 40 substrate, 200, 200a to 200d calculation circuit, Y reference line, Z first straight line, X second straight line, XZ reference plane, V a ~V j Output voltage, V det Voltage signal (weighted sum), w0,w1,w2,-w0,-w1,-w2 weighting coefficients.

Claims

1. an even number of magnetic sensing elements, four or more, arranged side by side in a reference plane perpendicular to a reference line extending in a predetermined reference direction; the even number of magnetic sensitive elements include a first pair of magnetic sensitive elements arranged at positions that are line-symmetric with respect to a first straight line that passes through an intersection of the reference line and the reference plane and is perpendicular to the reference line; the even number of magnetic sensitive elements include a second pair of magnetic sensitive elements arranged at positions that are line-symmetric with respect to a second line that is perpendicular to both the reference line and the first line and passes through the intersection point; Each of the sensitivity axes of one of the first pair of magnetic sensitive elements coincides with a sensitivity axis obtained by mirror-inverting and inverting the sensitivity axis of the other of the first pair of magnetic sensitive elements with respect to the first straight line, or with a sensitivity axis obtained by mirror-inverting the sensitivity axis of the other of the first pair of magnetic sensitive elements with respect to the first straight line, Each of the sensitivity axes of one of the second pair of magnetic sensitive elements coincides with a sensitivity axis obtained by mirror-inverting and inverting the sensitivity axis of the other of the second pair of magnetic sensitive elements with respect to the second straight line, or with a sensitivity axis obtained by mirror-inverting the sensitivity axis of the other of the second pair of magnetic sensitive elements with respect to the second straight line, The sensitivity axes of one or more pairs of magnetic sensitive elements among the even number of magnetic sensitive elements are inclined with respect to both the first straight line and the second straight line. A current sensor characterized by:

2. The even number of magnetic sensitive elements includes four magnetic sensitive elements arranged at positions away from the second straight line.

2. The current sensor according to claim 1.

3. The even number of magnetic sensing elements are four magnetic sensing elements arranged at positions spaced apart from the second straight line; Two magnetic sensing elements arranged on the second straight line; Contains 2. The current sensor according to claim 1.

4. The even number of magnetic sensing elements are a first group of magnetic sensing elements; a second group of magnetic sensitive elements arranged at a position farther from the second straight line than the first group of magnetic sensitive elements; Including, the first magnetic sensing element group includes four magnetic sensing elements arranged at positions away from the second straight line, The second group of magnetically sensitive elements includes four magnetically sensitive elements.

2. The current sensor according to claim 1.

5. The even number of magnetic sensing elements are a first group of magnetic sensing elements; a second group of magnetic sensitive elements arranged at a position farther from the second straight line than the first group of magnetic sensitive elements; Including, The first group of magnetic sensing elements includes: four magnetic sensing elements arranged at positions spaced apart from the second straight line; Two magnetic sensing elements arranged on the second straight line; Including, The second group of magnetically sensitive elements includes four magnetically sensitive elements.

2. The current sensor according to claim 1.

6. In the first quadrant of an XZ coordinate system having the second straight line as the X axis, the first straight line as the Z axis, and the intersection of the X axis and the Z axis as the origin, the +Z direction is set as 0° as the reference direction, and in a right-handed XYZ coordinate system having the X axis, the Z axis, and the Y axis perpendicular to both the X axis and the Z axis as its coordinate axes, when the rotation direction when a right-handed screw advances in the +Y direction is taken as positive, the angle θ of the sensitivity axis of the magnetic sensing element of the first magnetic sensing element group from the reference direction is １ is 180°≦θ １ ≦270° or 0°≦θ １ ≦90°, and the angle θ of the sensitivity axis of the magnetic sensing element of the second magnetic sensing element group in the first quadrant from the reference direction ２ is 60°≦θ ２ ≦120° or 240°≦θ ２ ≦300° 6. The current sensor according to claim 5.

7. The measuring device further includes an arithmetic circuit that calculates, based on the outputs of the even number of magnetic sensing elements, a value indicating a current flowing through a current path to be measured that is disposed on the reference line so as to extend in the reference direction.

7. The current sensor according to claim 1, wherein the current sensor is a current sensor.

8. The present invention further includes an arithmetic circuit for calculating a value indicating a current flowing through a current path to be measured, which is disposed on the reference line so as to extend in the reference direction, based on a weighted sum of the outputs of the even number of magnetic sensing elements.

7. The current sensor according to claim 1, wherein the current sensor is a current sensor.

9. The outputs of at least one of the first pair and the second pair of magnetic sensing elements are multiplied by weighting coefficients of equal magnitude.

9. The current sensor according to claim 8.

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