Magnetic sensor, correction circuit, magnetic sensor module, electrical control device, and correction method

Abstract

A magnetic sensor capable of correcting a hysteresis error caused by a residual magnetic flux from a soft magnetic body, and including a soft magnetic body including a first soft magnetic body and a second soft magnetic body, and a magnetic detection section that detects a physical quantity using an applied detection magnetic flux, the magnetic detection section including a first magnetic detection section and a second magnetic detection section. The detection magnetic flux includes a first detection magnetic flux applied to the first magnetic detection section and a second detection magnetic flux applied to the second magnetic detection section, and the residual magnetic flux generated from the soft magnetic body includes a first residual magnetic flux that can be applied to the first magnetic detection section and a second residual magnetic flux that can be applied to the second magnetic detection section. The first and second magnetic detection sections are arranged at positions where a ratio of the first residual magnetic flux to the first detection magnetic flux and a ratio of the second residual magnetic flux to the second detection magnetic flux are different, and a corrected physical quantity corrected for the hysteresis error caused by the residual magnetic flux is obtained based on a difference between first and second output values from the first and second magnetic detection sections.

Description

Technical Field

[0001] This invention relates to magnetic sensors, calibration circuits, magnetic sensor modules, electrical control devices, and calibration methods. Background Technology

[0002] In recent years, physical quantity detection devices (position detection devices) have been used for various applications to detect physical quantities (e.g., position caused by linear movement of a moving body, amount of movement (change), etc.). For example, such position detection devices are used to detect the position of clutches in automobile transmissions, or to detect the amount of pressure applied to various pedals. As such position detection devices, magnetic sensors are known, comprising a magnetic sensor element capable of detecting changes in an external magnetic field and a magnetic field generating part (e.g., a magnet or coil) capable of changing the relative position with respect to the magnetic sensor. In a magnetic sensor, a sensor signal corresponding to the change in the external magnetic field is output from the magnetic sensor element.

[0003] As magnetic sensors, those having a yoke and magnetic shield made of a soft magnetic material are known. The yoke applies magnetic flux generated by the magnetic field generating part to the magnetic sensor element. The magnetic shield suppresses so-called interfering magnetic flux other than the magnetic flux generated by the magnetic field generating part from being applied to the magnetic sensor element. By having such a yoke and magnetic shield, a sensor signal with reduced output error can be achieved.

[0004] Furthermore, current sensors are used in power control equipment such as hybrid electric vehicles (HEVs) and electric vehicles (EVs) for measuring battery capacity, measuring motor drive current, and in converters and inverters. These current sensors utilize magnetic sensors that include magnetic sensor elements capable of detecting the magnetic flux generated by current flowing through conductors such as busbars. For example, current sensors employ magnetic sensor elements such as magnetoresistive elements (AMR elements, GMR elements, TMR elements, etc.) and Hall effect elements to detect the current flowing through conductors such as busbars in a non-contact state.

[0005] Currently, known current sensors include an annular soft magnetic core with a gap, in which a magnetic sensor element is disposed (see Patent Document 1). By having such a structure, magnetic flux generated from a current-flowing conductor can be concentrated into the soft magnetic core, and the magnetic flux concentrated by the soft magnetic core can be applied to the magnetic sensor element disposed within the gap.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent No. 4321412 Summary of the Invention

[0009] The technical problem that the invention aims to solve

[0010] In the magnetic sensors described above, the core, yoke, and magnetic shield, all made of soft magnetic materials, are magnetized by the detection flux and external disturbance flux to be detected by the magnetic sensor element. Even in a zero magnetic field where these fluxes are absent, a relatively weak magnetization remains. Due to this residual magnetization in the soft magnetic material, a residual flux is generated even in a zero magnetic field. The magnetic detection element detects this residual flux, resulting in a so-called hysteresis error. This hysteresis error leads to a decrease in the detection accuracy of the magnetic sensor.

[0011] In view of the above problems, the object of the present invention is to provide a magnetic sensor, a correction circuit, a magnetic sensor module, an electrical control device, and a correction method capable of correcting hysteresis errors caused by residual magnetic flux from soft magnetic materials.

[0012] Technical solutions for solving technical problems

[0013] To address the aforementioned problems, the present invention provides a magnetic sensor comprising a soft magnetic body and a magnetic detection unit. The soft magnetic body includes a first soft magnetic body and a second soft magnetic body. The magnetic detection unit detects a physical quantity using an applied detection magnetic flux. The magnetic detection unit includes a first magnetic detection unit and a second magnetic detection unit. The detection magnetic flux includes a first detection magnetic flux applied to the first magnetic detection unit and a second detection magnetic flux applied to the second magnetic detection unit. A residual magnetic flux generated from the soft magnetic body includes a first residual magnetic flux that can be applied to the first magnetic detection unit and a second residual magnetic flux that can be applied to the second magnetic detection unit. The first and second magnetic detection units are disposed at positions where the ratio of the first residual magnetic flux to the first detection magnetic flux differs from the ratio of the second residual magnetic flux to the second detection magnetic flux. A correction physical quantity is obtained based on the difference between a first output value from the first magnetic detection unit and a second output value from the second magnetic detection unit. The correction physical quantity is a physical quantity that corrects the hysteresis error caused by the residual magnetic flux of the soft magnetic body included in the physical quantity detected by the magnetic detection unit.

[0014] In the above-mentioned magnetic sensor, the first residual magnetic flux and the second residual magnetic flux may be different, and the first detection magnetic flux and the second detection magnetic flux may also be different.

[0015] In the above-mentioned magnetic sensor, the correction physical quantity, which corrects the hysteresis error contained in the physical quantity detected by the magnetic detection unit, can also be obtained by the following formulas (1) to (4).

[0016] I exp =c×I′…(1)

[0017] I′=I1-K×Δ…(2)

[0018] K=a×Br1 / (a×Br1-b×Br2)…(3)

[0019] Δ=(a×B1-b×B2)+(a×Br1-b×Br2)…(4)

[0020] In the above equations (1) to (4), I exp denoted as “correction physical quantity”, c represents “conversion factor”, △ represents “difference between the first output value and the second output value”, I1 represents “first output value”, Br1 represents “first residual magnetic flux”, Br2 represents “second residual magnetic flux”, B1 represents “first detection magnetic flux”, B2 represents “second detection magnetic flux”, a represents “conversion rate of the first detection magnetic flux to a physical quantity”, and b represents “conversion rate of the second detection magnetic flux to a physical quantity”.

[0021] In the aforementioned magnetic sensor, the first magnetic detection unit and the second magnetic detection unit may also be disposed in a magnetic flux interference region where the first residual magnetic flux and the second residual magnetic flux interfere with each other.

[0022] In the aforementioned magnetic sensor, the first soft magnetic body may be a magnetic core comprising a first portion, a second portion connected to a first end of the first portion, and a third portion connected to a second end of the first portion. The first and second ends are opposite each other at a distance from each other in a second direction orthogonal to the first direction. The second and third portions are respectively connected to the first and second ends along a third direction orthogonal to the first and second directions. The magnetic detection unit is located in the core gap between the second and third portions. The second soft magnetic body comprises a first magnetic shield and a second magnetic shield, wherein the first and second magnetic shields are positioned to overlap with the core gap when viewed along the third direction, and the magnetic detection unit is positioned sandwiched between the first and second magnetic shields. Alternatively, the detection magnetic flux may be generated by the flow of current in a conductor.

[0023] The present invention provides a correction circuit that corrects the output from the aforementioned magnetic sensor and includes a correction unit, wherein the correction unit corrects the hysteresis error caused by the residual magnetic flux of the soft magnetic body included in the physical quantity detected by the aforementioned magnetic detection unit, and the correction unit corrects the hysteresis error based on a first output value from the aforementioned first magnetic detection unit and a second output value from the aforementioned second magnetic detection unit.

[0024] In the above correction circuit, the correction unit may also correct the hysteresis error by the following formulas (1) to (4).

[0025] I exp =c×I′…(1)

[0026] I′=I1-K×Δ…(2)

[0027] K=a×Br1 / (a×Br1-b×Br2)…(3)

[0028] Δ=(a×B1-b×B2)+(a×Br1-b×Br2)…(4)

[0029] The present invention provides a magnetic sensor module having the above-described magnetic sensor and the above-described correction circuit.

[0030] The present invention provides an electrical control device including the above-mentioned magnetic sensor; and provides an electrical control device including the above-mentioned magnetic sensor module.

[0031] The present invention provides a correction method for correcting a physical quantity detected by the magnetic sensor, comprising: obtaining a first output value from the first magnetic detection unit and a second output value from the second magnetic detection unit; and correcting, based on the first output value and the second output value, the hysteresis error caused by the residual magnetic flux of the soft magnetic body contained in the physical quantity detected by the magnetic detection unit to obtain the corrected physical quantity.

[0032] In the above correction method, the above hysteresis error can be corrected by the following formulas (1) to (4).

[0033] I exp =c×T…(1)

[0034] I′=I1-K×Δ…(2)

[0035] K=a×Br1 / (a×Br1-b×Br2)…(3)

[0036] Δ=(a×B1-b×B2)+(a×Br1-b×Br2)…(4)

[0037] Invention Effects

[0038] According to the present invention, a magnetic sensor, a correction circuit, a magnetic sensor module, an electrical control device, and a correction method are provided that can correct hysteresis errors caused by residual magnetic flux from soft magnetic materials. Attached Figure Description

[0039] Figure 1This is a perspective view showing a schematic structure of a current sensor according to one embodiment of the present invention.

[0040] Figure 2 This is a schematic diagram showing the schematic structure of a current sensor in one embodiment of the present invention with the cut end face shown.

[0041] Figure 3 This is a schematic diagram showing the schematic structure of a current sensor in one embodiment of the present invention with the cut end face shown.

[0042] Figure 4 This is a schematic diagram showing the schematic structure of a current sensor in one embodiment of the present invention with the cut end face shown.

[0043] Figure 5 This is a schematic diagram showing the schematic structure of a current sensor in one embodiment of the present invention with the cut end face shown.

[0044] Figure 6 This is a schematic diagram showing the schematic structure of a current sensor in one embodiment of the present invention with the cut end face shown.

[0045] Figure 7 This is a schematic diagram showing the schematic structure of a current sensor in one embodiment of the present invention with the cut end face shown.

[0046] Figure 8 This is a perspective view showing a schematic structure of a current sensor according to one embodiment of the present invention.

[0047] Figure 9 This is a block diagram illustrating the schematic structure of a current sensor in one embodiment of the present invention.

[0048] Figure 10 This is a block diagram illustrating a structural example of an electrical control device in one embodiment of the present invention. Detailed Implementation

[0049] The magnetic sensor according to an embodiment of the present invention will be described with reference to the accompanying drawings. In this embodiment, a current sensor as a magnetic sensor is used as an example for description, but the magnetic sensor of this embodiment is not limited to a current sensor.

[0050] In describing this embodiment, "first direction, second direction, and third direction" are specified in several figures as needed. Here, the first direction is the direction of the current flowing in the conductor. The second direction is a direction orthogonal to the first direction and is the width direction of the conductor. The third direction is a direction orthogonal to the first and second directions and is the thickness direction of the conductor. Furthermore, in this specification and figures, the first direction is sometimes referred to as the "Z direction", the second direction as the "X direction", and the third direction as the "Y direction".

[0051] like Figures 1-4 As shown, the current sensor 1 in this embodiment includes a magnetic detection unit 2 capable of detecting magnetic flux, a magnetic core 3 (first soft magnetic body), a magnetic shield 4 (second soft magnetic body), and a conductor 5 in which current flows in the Z direction.

[0052] The magnetic core 3 is a soft magnetic material that concentrates magnetic flux through which magnetic flux generated by the flow of current in the conductor 5 passes. The magnetic core 3 is arranged to surround the conductor 5 along an XY plane orthogonal to the Z direction. The concept of surrounding the conductor 5 includes not only a ring-shaped form around the conductor 5, but also a partially missing form opposite to a portion of the conductor 5's perimeter, referred to as a so-called C-shaped core. The magnetic core 3 includes a first core 31, a second core 32, a third core 33, a fourth core 34, and a fifth core 35. The first core 31, fourth core 34, and fifth core 35 all extend in, for example, the width direction of the conductor 5, i.e., the X direction. The second core 32 and third core 33 both extend in, for example, the thickness direction of the conductor 5, i.e., the Y direction. The first core 31 is arranged opposite to the fourth core 34 and the fifth core 35 in the Y direction. The second core 32 and third core 33 are arranged opposite to each other in the X direction. The second core 32 is configured such that the first end portion 311 in the X direction of the first core 31 is connected to the first end portion 341 in the X direction of the fourth core 34. The second end portion 342 opposite to the first end portion 341 in the X direction of the fourth core 34 has a first end face S34. The third core 33 is configured such that the second end portion 312 opposite to the first end portion 311 in the X direction of the first core 31 is connected to the first end portion 351 in the X direction of the fifth core 35. The second end portion 352 opposite to the first end portion 351 in the X direction of the fifth core 35 has a second end face S35. The first end face S34 and the second end face S35 are spaced apart from each other in the X direction. The space between the first end face S34 and the second end face S35 is a core gap CG. The core gap CG has a predetermined width in the X direction. Furthermore, in Figures 1-6 The diagram shows the first core 31, the second core 32, the third core 33, the fourth core 34, and the fifth core 35 connected to each other in a physical contact manner, but the magnetic core 3 in this embodiment is not limited to this method. For example, the first core 31, the second core 32, the third core 33, the fourth core 34, and the fifth core 35 may not be in physical contact, as long as they are magnetically connected to each other.

[0053] In this embodiment, the connection portions of the first core portion 31 and the second core portion 32, the connection portion of the first core portion 31 and the third core portion 33, the connection portion of the second core portion 32 and the fourth core portion 34, and the connection portion of the third core portion 33 and the fifth core portion 35 of the magnetic core 3 all have curved shapes (rounded corner shapes), but are not limited to this method. For example, these connection portions can be bent shapes (shapes with corners), or they can be C-shaped with corners chamfered.

[0054] The length of the core gap CG in the X direction (the distance in the X direction between the first end face S34 of the fourth core 34 and the second end face S35 of the fifth core 35) can be appropriately set so that the current sensor 1 can perform the desired characteristics, for example, 6 mm or more.

[0055] The magnetic detection unit 2 includes a first magnetic detection unit 21 and a second magnetic detection unit 22. The first magnetic detection unit 21 and the second magnetic detection unit 22 are disposed near or within the core gap CG. When current flows in the conductor 5, magnetic flux is generated from the conductor 5, and this magnetic flux is concentrated into the magnetic core 3 having the core gap CG. Since the magnetic core 3 is annular with the core gap CG, the entire magnetic core 3, including the core gap CG, becomes a path (magnetic circuit) for the magnetic flux. The magnetic flux concentrated into the magnetic core 3 is the detection magnetic flux applied to the magnetic detection unit 2, including a first detection magnetic flux B1 applied to the first magnetic detection unit 21 and a second detection magnetic flux B2 applied to the second magnetic detection unit 22. Furthermore, since "magnetic flux" (detection flux, residual flux, etc.) and "magnetic flux density" can be substantially synonymous in this invention, "magnetic flux" can also be referred to as "magnetic flux density".

[0056] The first detection magnetic flux B1 applied to the first magnetic detection unit 21 and the second detection magnetic flux B2 applied to the second magnetic detection unit 22 are different from each other (B1 ≠ B2). In other words, the first magnetic detection unit 21 and the second magnetic detection unit 22 are respectively located at positions where different detection magnetic fluxes (first detection magnetic flux B1 and second detection magnetic flux B2) are applied. Preferably, the first magnetic detection unit 21 is located at the position where the magnetic flux generated by the current flowing in the conductor 5 and concentrated in the magnetic core 3 is at its maximum (maximum efficiency position), and the second magnetic detection unit 22 is located at a position other than this maximum efficiency position. For example, such as Figure 1 and Figure 2 As shown, the first magnetic detection unit 21 and the second magnetic detection unit 22 can be disposed within the core gap CG, at positions with different lengths from the conductor 5 in the Y direction, with the first magnetic detection unit 21 disposed at the position of maximum efficiency. Additionally, as... Figure 5 and Figure 6As shown, the first magnetic detection unit 21 can also be located at the maximum efficiency position within the core gap, and the second magnetic detection unit 22 can be located outside the core gap CG.

[0057] The magnetic shielding member 4 includes a first magnetic shielding member 41 and a second magnetic shielding member 42 that overlap with the core gap CG when viewed along the Y direction. The second magnetic shielding member 42 is located closer to the conductor 5 than the first magnetic shielding member 41. When viewed along the Y direction, the magnetic detection units 2 (first magnetic detection unit 21 and second magnetic detection unit 22) are arranged between the first magnetic shielding member 41 and the second magnetic shielding member 42. The first magnetic shielding member 41 and the second magnetic shielding member 42 are connected in the +Z direction via a third magnetic shielding member 43. That is, when viewed along the X direction, the magnetic shielding member 4 has a substantially C-shaped form.

[0058] Both the magnetic core 3 and the magnetic shield 4 can be made of soft magnetic materials such as silicon steel, electromagnetic steel, pure iron (SUY), and permalloy, but from the perspective of cost reduction, silicon steel, electromagnetic steel, and pure iron are preferred. The iron loss of the material constituting the magnetic shield 4 only needs to be greater than that of the material constituting the magnetic core 3. The magnetic flux generated from the conductor 5 due to the flow of a specified current in the conductor 5 is concentrated in the magnetic core 3 and the magnetic shield 4. When the frequency of the current flowing in the conductor 5 increases, the frequency characteristics of the magnetic shield 4, which is made of a material with relatively high iron loss, deteriorate, and the magnetic flux concentrated in the magnetic shield 4 relatively decreases. Although the frequency characteristics of the magnetic core 3, which is made of a material with relatively low iron loss, also deteriorate, and the magnetic flux is difficult to concentrate, the magnetic flux concentrated in the magnetic core 3 increases relatively by the amount by which the magnetic flux concentrated in the magnetic shield 4 decreases. As a result, compared with the current sensor 1 without the magnetic shield 4, the detection magnetic flux applied to the magnetic detection unit 2 is considered stable, which can stabilize the response characteristics of the current sensor 1 to alternating current. Furthermore, the material used to construct the magnetic core 3 only needs to be a material with lower iron loss than the material used to construct the magnetic shield 4. It can be the same type of material as the material used to construct the magnetic shield 4, or it can be a different type of material. For example, both the magnetic core 3 and the magnetic shield 4 are made of electromagnetism, but the iron loss of the electromagnetism constituting the magnetic shield 4 only needs to be greater than the iron loss of the electromagnetism constituting the magnetic core 3.

[0059] The conductor 5, made of copper or the like, is a plate-like body with its long side direction substantially parallel to the Z-direction and its thickness direction substantially parallel to the Y-direction. It is arranged such that it passes through a ring-shaped magnetic core 3 with a core gap CG in the Z-direction. The long side direction of the conductor 5 only needs to be substantially parallel to the Z-direction; for example, the axis of the conductor 5 (the line passing through the center of the conductor 5) only needs to intersect the Z-direction at an angle of 2° or less. Similarly, the thickness direction of the conductor 5 only needs to be substantially parallel to the Y-direction; for example, it only needs to intersect the Y-direction at an angle of 2° or less.

[0060] The magnetic flux generated in conductor 5 by the current flowing through it is concentrated into a magnetic core 3 with a core gap CG. Since the magnetic core 3 is annular with a core gap CG, the entire magnetic core 3, including the core gap CG and the magnetic shield 4, constitutes the path (magnetic circuit) of the magnetic flux. The magnetic flux generated from conductor 5 varies depending on the distance from conductor 5. Figures 1-6 In the manner shown, the first magnetic detection unit 21 and the second magnetic detection unit 22 are positioned at locations where different detection magnetic fluxes (first detection magnetic flux B1 and second detection magnetic flux B2) are applied to each other.

[0061] When current flows through conductor 5 and magnetic flux is generated from conductor 5, the magnetic core 3 and magnetic shield 4, made of soft magnetic material, are magnetized. Even in the state where no magnetic flux is generated from conductor 5, i.e., when no current flows through conductor 5 (zero magnetic field state), the magnetic core 3 and magnetic shield 4 are still magnetized and have residual magnetization M, generating residual magnetic flux. Since the residual magnetic flux from the magnetic core 3 and magnetic shield 4 is applied to the magnetic detection unit 2, hysteresis error may occur in the output from the current sensor 1. The residual magnetic flux includes at least a first residual magnetic flux Br1 that can be applied to the first magnetic detection unit 21 and a second residual magnetic flux Br2 that can be applied to the second magnetic detection unit 22. The first residual magnetic flux Br1 is, for example, a magnetic flux in the +X direction generated from the magnetic core 3. The second residual magnetic flux Br2 is, for example, a magnetic flux in the -X direction generated from the magnetic shield 4. The first residual magnetic flux Br1 and the second residual magnetic flux Br2 are different from each other (Br l ≠Br2). In other words, the first magnetic detection unit 21 and the second magnetic detection unit 22 are respectively disposed at positions where different residual magnetic fluxes (first residual magnetic flux Br1 and second residual magnetic flux Br2) are applied. The residual magnetic flux can cause interference in the region between the first magnetic shield 41 and the second magnetic shield 42 in the core gap CG. That is, in Figure 1 In the illustrated configuration, this region can be a flux interference region where the first residual magnetic flux Br1 and the second residual magnetic flux Br2 interfere with each other. Within this flux interference region, the ratio of the first residual magnetic flux Br1 to the first detected magnetic flux B1 (Br1 / B1) differs from the ratio of the second residual magnetic flux Br2 to the second detected magnetic flux B2 (Br2 / B2). By arranging the first magnetic detection unit 21 and the second magnetic detection unit 22 at positions within the flux interference region where these ratios (Br1 / B1 and Br2 / B2) differ from each other, it is possible to correct for hysteresis errors that may arise from the detection of residual magnetic flux by the first magnetic detection unit 21 and the second magnetic detection unit 22.

[0062] In the current sensor 1 with the above-described structure, the magnetic flux generated by the current flowing in the conductor 5 is concentrated in the magnetic core 3. The flow of the magnetic flux concentrated in the magnetic core 3 forms a ring-shaped magnetic flux loop centered on the conductor 5 in the XY plane. In this embodiment, the first magnetic detection unit 21 and the second magnetic detection unit 22 are provided on magnetic flux loops with different magnetic fluxes. Furthermore, the first magnetic detection unit 21 is provided at the position where the first residual magnetic flux Br1 is applied, and the second magnetic detection unit 22 is provided at the position where a second residual magnetic flux Br2 with a different magnetic flux density than the first residual magnetic flux Br1 is applied. Thus, as will be described later, hysteresis errors that may occur in the first magnetic detection unit 21 and the second magnetic detection unit 22 due to the detection of residual magnetic flux can be corrected. Therefore, the current sensor 1 according to this embodiment can detect the current flowing through the conductor 5 with high accuracy.

[0063] like Figure 9 As shown, the current sensor 1 in this embodiment may also include a signal processing unit 6. The signal processing unit 6 only needs to include an A / D (analog-to-digital) converter 61 and an arithmetic unit 62. The A / D converter 61 converts the analog signal output from the magnetic detection unit 2 into a digital signal, and the arithmetic unit 62 performs arithmetic processing on the digital signal converted by the A / D converter 61. Furthermore, when the arithmetic processing result obtained by the arithmetic unit 62 is output as an analog signal, the signal processing unit 6 only needs to include a D / A (digital-to-analog) converter (not shown) downstream of the arithmetic unit 62. Furthermore, the current sensor 1 in this embodiment may also be configured together with the signal processing unit 6 to form a current sensor module.

[0064] In this embodiment, the magnetic detection unit 2 may include one element unit or multiple element units (e.g., the first to fourth element units). When multiple element units are included, a Wheatstone bridge circuit composed of multiple element units may be constructed (a full-bridge circuit composed of the first to fourth element units, or a half-bridge circuit composed of the first and second element units). The element unit may include a single magnetoresistive element (AMR element, GMR element, TMR element, etc.) or a Hall element, or it may include multiple magnetoresistive elements or Hall elements.

[0065] The A / D converter 61 converts the sensor signal (an analog signal related to current) output from the current sensor 1 into a digital signal, which is then input to the arithmetic unit 62. The arithmetic unit 62 performs correction processing to correct hysteresis errors contained in the digital signal converted from the analog signal by the A / D converter 61, or performs arithmetic processing. This arithmetic unit 62 is, for example, a microcomputer or an ASIC (Application Specific Integrated Circuit). In this embodiment, the arithmetic unit 62 or the signal processing unit 6 containing the arithmetic unit 62 constitutes a correction circuit.

[0066] The correction process for hysteresis error in the arithmetic unit 62 is explained.

[0067] The conversion rate for converting the first detection magnetic flux B1 applied to the first magnetic detection unit 21 into a current value is "a", and the conversion rate for converting the second detection magnetic flux B2 applied to the second magnetic detection unit 22 into a current value is "b". Furthermore, conversion rate a represents the ratio of the maximum rated current value Im obtained from the output of the first magnetic detection unit 21 to the maximum rated value Bm1 of the first detection magnetic flux B1 applied to the first magnetic detection unit 21. Conversely, conversion rate b represents the ratio of the maximum rated current value Im obtained from the output of the second magnetic detection unit 22 to the maximum rated value Bm2 of the second detection magnetic flux B2 applied to the second magnetic detection unit 22. In relation to the first detection magnetic flux B1, the second detection magnetic flux B2, the first residual magnetic flux Br1, and the second residual magnetic flux Br2, the current value I1 obtained from the output of the first magnetic detection unit 21 and the current value I2 obtained from the output of the second magnetic detection unit 22 can be obtained using the following equations (5) and (6).

[0068] I1=a×B1+a×Br1…(5)

[0069] I2=b×B2+b×Br2…(6)

[0070] Furthermore, if the difference between the current value I1 obtained from the output of the first magnetic detection unit 21 and the current value I2 obtained from the output of the second magnetic detection unit 22 is set as “△”, then the difference △ can be obtained by the following formula (7).

[0071] Δ=I1-I2

[0072] =(a×B1-b×B2)+(a×Br1-b×Br2)…(7)

[0073] In the above formula (7), “a×B1” and “b×B2” are the actual current values ​​I flowing in conductor 5 when no first residual magnetic flux Br1 and second residual magnetic flux Br2 are applied to the first magnetic detection unit 21 and the second magnetic detection unit 22. expTherefore, we can say that a × B1 = b × B2 = I exp .

[0074] In the above formula (7), “a×Br1-b×Br2” represents a value that depends on the magnetization state of the magnetic core 3 and the magnetic shield 4, which are made of soft magnetic materials. Here, the current value I' obtained by subtracting the difference Δ multiplied by the constant K from the current value I1 obtained from the output of the first magnetic detection unit 21 is represented by the following formulas (8) and (9).

[0075] I'=11-K×Δ

[0076] =a×B1+a×Br1-K{(a×B1-b×B2)+(a×Br1-b×Br2)}

[0077] = a×B1-K×a×B1+K×b×B2

[0078] = a×B1(1-K)-b×K×B2…(8)

[0079] K=a×Br1 / (a×Br1-b×Br2)…(9)

[0080] In the above equation (8), since there are no terms related to the first residual magnetic flux Br1 and the second residual magnetic flux Bt2, it can be understood that the current value I' does not include the hysteresis error that may be caused by the residual magnetic flux. Moreover, by pre-calculating the above current value I' into the true current value I flowing in conductor 5, the current value I' can be converted into the actual current value I in conductor 5. exp The conversion factor c can be used to calculate the true current value I flowing in conductor 5 using the following formula (10). exp .

[0081] I exp =c×I'…(10)

[0082] The constant K and coefficient c mentioned above can be calculated in advance using the correct measurement system of the current sensor 1 in this embodiment. The constant K can be calculated based on the maximum magnetization state using the following formula (11) in relation to the first detection magnetic flux (maximum rated value Bm1) and the first residual magnetic flux Br1max detected by the first magnetic detection unit 21 when the current of the maximum rated value Im flows through the conductor 5, the second detection magnetic flux (maximum rated value Bm2) and the second residual magnetic flux Br2max detected by the second magnetic detection unit 22.

[0083]

[0084] Thus, in the current sensor 1 of this embodiment, the first magnetic detection unit 21 and the second magnetic detection unit 22 are disposed on magnetic flux loops with different magnetic flux densities. The first magnetic detection unit 21 is disposed at the position where the first residual magnetic flux Br1 is applied, and the second magnetic detection unit 22 is disposed at the position where a second residual magnetic flux Br2, which is different from the first residual magnetic flux Br1, is applied. Therefore, the hysteresis error contained in the output of the current sensor 1 can be corrected using the following formulas (1) to (4), and the true current value I can be detected with high accuracy. exp .

[0085] I exp =c×I'…(1)

[0086] I'=I1-K×Δ…(2)

[0087] K=a×Br1 / (a×Br1-b×Br2)…(3)

[0088] Δ=(a×B1-b×B2)+(a×Br1-b×Br2)…(4)

[0089] The current sensor 1 in this embodiment can be installed in an electrical control device. Furthermore, examples of electrical control devices in this embodiment include battery management systems, inverters, and converters for hybrid electric vehicles (HEVs) and electric vehicles (EVs). The current sensor 1 in this embodiment is used to measure the input and output current from the power source and output information related to the measured current to the electrical control device. Figure 10 As shown, for example, the electrical control device 10 only needs to include a current sensor 1, a power supply device 11, and a control circuit 12. The current sensor 1 detects the current output from or input to the power supply device 11. Information related to the current value detected by the current sensor 1 is sent to the control circuit 12. The control circuit 12, for example, controls the operation of the current sensor 1 and the operation of the power supply device 11. The control circuit 12, for example, adjusts the output current from the power supply device 11 based on the information from the current sensor 1.

[0090] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit the present invention. Therefore, the essence of the elements disclosed in the above embodiments is to also include all design modifications and equivalents that fall within the technical scope of the present invention.

[0091] In the above embodiment, the magnetic core 3 is described as an example comprising a first core 31, a second core 32, a third core 33, a fourth core 34, and a fifth core 35, but it is not limited to this method. For example, it may also be as follows: Figure 5 and Figure 6 As shown, the magnetic core 3 includes a first core portion 31, a second core portion 32, and a third core portion 33, but does not include a fourth core portion 34 and a fifth core portion 35. In this case, the first magnetic detection unit 21 only needs to be disposed within the core gap CG between the end of the second core portion 32 and the end of the third core portion 33. The second magnetic detection unit 22 can be disposed outside the core gap CG and at a position along the Y direction further away from the conductor 5 than the first magnetic detection unit 21 (see reference). Figure 5 Alternatively, it can be positioned between the end of the second core 32 and the magnetic shield 4 (see reference). Figure 6 Additionally, for example, it can also be like... Figure 7 As shown, the magnetic core 3 is not provided, and the conductor 5, the first magnetic detection unit 21, and the second magnetic detection unit 22 are located between the two magnetic shields 4, 4.

[0092] In the above embodiment, an example was described that includes a magnetic core 3 and two magnetic detection units 2 (a first magnetic detection unit 21 and a second magnetic detection unit 22), but the embodiment is not limited to this. For example, it may also be as follows: Figure 8 As shown, the current sensor 1 includes a first magnetic core 3A and a second magnetic core 3B composed of different types of soft magnetic materials. A first magnetic detection unit 21 is provided in the core gap CG1 of the first magnetic core 3A, and a second magnetic detection unit 22 is provided in the core gap CG2 of the second magnetic core 3B. In this case, it is sufficient that the residual magnetic flux of the soft magnetic material constituting the first magnetic core 3A is different from that of the soft magnetic material constituting the second magnetic core 3B. For example, the soft magnetic material constituting the first magnetic core 3A can be a silicon steel plate with a relatively large residual magnetic flux, and the soft magnetic material constituting the second magnetic core 3B can be a permalloy with a relatively small residual magnetic flux.

[0093] In the above embodiment, a current sensor 1 for detecting the current flowing in the conductor 5 was used as an example, but it is not limited to this method. For example, it could also be a magnetic sensor for detecting the position of a moving body that moves linearly or rotationally.

[0094] Example

[0095] The present invention will be described in more detail below with examples, but the present invention is not limited to the examples described below.

[0096] [Experimental Example]

[0097] Use with Figure 1 and Figure 2The current sensor 1 with the structure shown is used to vary the current flowing in the conductor 5 within the range of 20 to 600 A. The hysteresis error contained in the output of the current sensor 1 is calculated. As a result, it is confirmed that by performing hysteresis error correction processing using the arithmetic unit 62, a reduction in hysteresis error of more than 80% can be obtained compared with the case where no correction processing is performed.

[0098] Explanation of reference numerals in the attached figures

[0099] 1… Current sensor

[0100] 2…Magnetic Detection Department

[0101] 21…First Magnetic Detection Department

[0102] 22…Second Magnetic Detection Section

[0103] 3…Magnetic core

[0104] 4…Magnetic shielding components

[0105] 5… conductor.

Claims

1. A magnetic sensor, characterized in that: It includes a soft magnetic body and a magnetic detection unit, wherein the soft magnetic body comprises a first soft magnetic body and a second soft magnetic body, and the magnetic detection unit uses an applied detection magnetic flux to detect a physical quantity. The magnetic detection unit includes a first magnetic detection unit and a second magnetic detection unit. The detection magnetic flux includes a first detection magnetic flux applied to the first magnetic detection unit and a second detection magnetic flux applied to the second magnetic detection unit. The residual magnetic flux generated from the soft magnetic material includes a first residual magnetic flux that can be applied to the first magnetic detection unit and a second residual magnetic flux that can be applied to the second magnetic detection unit. Each of the first magnetic detection unit and the second magnetic detection unit is positioned at a different location within the magnetic flux interference region where the first residual magnetic flux and the second residual magnetic flux interfere with each other. The ratio of the first residual magnetic flux to the first detected magnetic flux is different from the ratio of the second residual magnetic flux to the second detected magnetic flux. The first residual magnetic flux is different from the second residual magnetic flux. The first residual magnetic flux is mainly generated by the first soft magnetic body, and the second residual magnetic flux is mainly generated by the second soft magnetic body. Based on the difference between the first output value from the first magnetic detection unit and the second output value from the second magnetic detection unit, a correction physical quantity is obtained, wherein the correction physical quantity is a physical quantity that corrects the hysteresis error caused by the residual magnetic flux of the soft magnetic body contained in the physical quantity detected by the magnetic detection unit.

2. The magnetic sensor according to claim 1, characterized in that: The first detection magnetic flux is different from the second detection magnetic flux.

3. The magnetic sensor according to claim 1, characterized in that: The corrected physical quantity, after correcting the hysteresis error contained in the physical quantity detected by the magnetic detection unit, is obtained by the following formulas (1) to (4). In the above equations (1) to (4), I exp denoted as "correction physical quantity", c represents "conversion factor", △ represents "difference between the first output value and the second output value", I1 represents "first output value", Br1 represents "first residual magnetic flux", Br2 represents "second residual magnetic flux", B1 represents "first detection magnetic flux", B2 represents "second detection magnetic flux", a represents "conversion rate of the first detection magnetic flux to a physical quantity", and b represents "conversion rate of the second detection magnetic flux to a physical quantity".

4. The magnetic sensor according to claim 1, characterized in that: The first soft magnetic material is a magnetic core comprising a first part, a second part connected to a first end of the first part, and a third part connected to a second end of the first part. The first end and the second end are opposite each other at a distance from each other in the second direction orthogonal to the first direction. The second part and the third part are respectively connected to the first end and the second end along a third direction orthogonal to the first direction and the second direction, The magnetic detection unit is located in the core gap between the second part and the third part. The second soft magnetic material includes a first magnetic shield and a second magnetic shield, wherein the first magnetic shield and the second magnetic shield are positioned to overlap with the core gap when viewed along the third direction. The magnetic detection unit is positioned between the first magnetic shield and the second magnetic shield.

5. The magnetic sensor according to claim 1, characterized in that: The detection magnetic flux is generated by the flow of current in a conductor.

6. A correction circuit, characterized in that: The correction circuit corrects the output from the magnetic sensor of claim 1, and includes a correction unit, wherein the correction unit corrects the hysteresis error caused by the residual magnetic flux of the soft magnetic body contained in the physical quantity detected by the magnetic detection unit. The correction unit corrects the hysteresis error based on a first output value from the first magnetic detection unit and a second output value from the second magnetic detection unit.

7. The correction circuit according to claim 6, characterized in that: The correction unit corrects the hysteresis error using the following formulas (1) to (4). In the above equations (1) to (4), I exp denoted as "correction physical quantity", c represents "conversion factor", △ represents "difference between the first output value and the second output value", I1 represents "first output value", Br1 represents "first residual magnetic flux", Br2 represents "second residual magnetic flux", B1 represents "first detection magnetic flux", B2 represents "second detection magnetic flux", a represents "conversion rate of the first detection magnetic flux to a physical quantity", and b represents "conversion rate of the second detection magnetic flux to a physical quantity".

8. A magnetic sensor module, characterized in that: It has the magnetic sensor as described in claim 1 and the correction circuit as described in claim 6 or 7.

9. An electrical control device, characterized in that: Includes the magnetic sensor as described in claim 1.

10. An electrical control device, characterized in that: Includes the magnetic sensor module as described in claim 8.

11. A calibration method, characterized in that: The calibration method is a method for calibrating the physical quantity detected by the magnetic sensor of claim 1, and includes: The steps of acquiring a first output value from the first magnetic detection unit and a second output value from the second magnetic detection unit; and The step of obtaining the corrected physical quantity by correcting the hysteresis error caused by the residual magnetic flux of the soft magnetic body contained in the physical quantity detected by the magnetic detection unit based on the first output value and the second output value.

12. The correction method according to claim 11, characterized in that: The hysteresis error is corrected by the following equations (1) to (4). In the above equations (1) to (4), I exp denoted as "correction physical quantity", c represents "conversion factor", △ represents "difference between the first output value and the second output value", I1 represents "first output value", Br1 represents "first residual magnetic flux", Br2 represents "second residual magnetic flux", B1 represents "first detection magnetic flux", B2 represents "second detection magnetic flux", a represents "conversion rate of the first detection magnetic flux to a physical quantity", and b represents "conversion rate of the second detection magnetic flux to a physical quantity".

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