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

Abstract

To provide a magnetic sensor capable of correcting hysteresis errors due to a residual magnetic flux from a soft magnetic body.SOLUTION: The magnetic sensor includes: a soft magnetic body that includes a first soft magnetic body and a second soft magnetic body; and a magnetic detection unit that detects a physical quantity by a detection magnetic flux to be applied. The magnetic detection unit includes a first magnetic detection unit and a second magnetic detection unit. The detection magnetic flux includes: a first detection flux that is applied to the first magnetic detection unit; and a second detection flux that is applied to the second magnetic detection unit. A residual magnetic flux generated from the soft magnetic body includes: a first residual flux that may be applied to the first magnetic detection unit; and a second residual flux that may be applied to the second magnetic detection unit. The first magnetic detection unit and the second magnetic detection unit are arranged at positions so that a ratio of the first residual magnetic flux to the first detection flux and a ratio of the second residual flux to the second detection flux are different. On the basis of a difference between first and second output values from the first and second magnetic detection units, a corrected physical quantity obtained by correcting a hysteresis error due to the residual magnetic flux is acquired.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a magnetic sensor, a correction circuit, a magnetic sensor module, an electric control device, and a correction method.

Background Art

[0002] In recent years, in various applications, a physical quantity detection device (position detection device) for detecting a physical quantity (for example, a position or a movement amount (change amount) due to linear movement of a moving object, etc.) has been used. For example, the above position detection device is used to detect the position of a clutch or the like in an automobile transmission or the depression amount of various pedals. As this position detection device, a magnetic sensor including a magnetic sensor element capable of detecting a change in an external magnetic field and a magnetic field generation unit (for example, a magnet or a coil) capable of changing the relative position with respect to the magnetic sensor is known. In the magnetic sensor, a sensor signal corresponding to a change in an external magnetic field is output from the magnetic sensor element.

[0003] As the magnetic sensor, those having a yoke made of a soft magnetic material, a magnetic shield, or the like are known. The yoke serves to apply the magnetic flux generated from the magnetic field generation unit to the magnetic sensor element. The magnetic shield serves to suppress the application of a so-called disturbance magnetic flux other than the magnetic flux generated from the magnetic field generation unit to the magnetic sensor element. By having such a yoke, a magnetic shield, or the like, a sensor signal with reduced error can be output.

[0004] Current sensors are also used to measure the remaining battery charge of hybrid electric vehicles (HEVs) and electric vehicles (EVs), measure the drive current of motors, and in power control equipment such as converters and inverters. These current sensors include magnetic sensors that contain magnetic sensor elements capable of detecting the magnetic flux generated when current flows through conductors such as busbars. In current sensors, for example, magnetic sensor elements such as magnetoresistive elements (AMR elements, GMR elements, TMR elements, etc.) and Hall elements detect the current flowing through conductors such as busbars in a non-contact manner.

[0005] Conventionally, current sensors are known to have a ring-shaped soft magnetic core with an air gap, in which a magnetic sensor element is arranged (see Patent Document 1). With such a structure, the magnetic flux generated from the conductor through which the current flows can be focused onto the soft magnetic core, and the magnetic flux focused by the soft magnetic core can be applied to the magnetic sensor element arranged in the air gap. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 4321412 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] In the magnetic sensor described above, the core, yoke, magnetic shield, etc., which are made of soft magnetic material, are magnetized by the detection flux and disturbance flux that are to be detected by the magnetic sensor element, and a relatively weak magnetization remains even in a zero magnetic field where the detection flux and disturbance flux do not exist. Due to the residual magnetization remaining in the soft magnetic material, residual magnetic flux is generated from the soft magnetic material even in a zero magnetic field. When the magnetic detection element detects this residual magnetic flux, a so-called hysteresis error occurs. This hysteresis error causes a problem in that the detection accuracy of the magnetic sensor decreases.

[0008] In view of the above issues, the present invention aims 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. [Means for solving the problem]

[0009] To solve the above problems, the present invention provides a magnetic sensor comprising a soft magnetic material including a first soft magnetic material and a second soft magnetic material, and a magnetic detection unit that detects a physical quantity by an applied detection magnetic flux, wherein 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, the first magnetic detection unit and the second magnetic detection unit are arranged in positions such that the ratio of the first residual magnetic flux to the first detection magnetic flux and the ratio of the second residual magnetic flux to the second detection magnetic flux are different, and a corrected physical quantity is obtained in which the hysteresis error due to the residual magnetic flux of the soft magnetic material included in the physical quantity detected by the magnetic detection unit is corrected 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.

[0010] In the magnetic sensor described above, the first residual magnetic flux and the second residual magnetic flux may be different, and the first detected magnetic flux and the second detected magnetic flux may be different.

[0011] In the above-described magnetic sensor, the corrected physical quantity obtained by correcting the hysteresis error included in the physical quantity detected by the magnetic detection unit may be obtained using the following formulas (1) to (4).

[0012]

number

[0013] In the above formulas (1) to (4), I exp ∫ represents the "corrected physical quantity", c represents the "conversion factor", Δ represents the "difference between the first output value and the second output value", I1 represents the "first output value", Br1 represents the "first residual flux", Br2 represents the "second residual flux", B1 represents the "first detected flux", B2 represents the "second detected flux", a represents the "conversion rate for converting the first detected flux into a physical quantity", and b represents the "conversion rate for converting the second detected flux into a physical quantity".

[0014] In the magnetic sensor described above, the first magnetic detection unit and the second magnetic detection unit may be arranged within a magnetic flux interference region in which the first residual magnetic flux and the second residual magnetic flux interfere with each other.

[0015] In the magnetic sensor described above, the first soft magnetic material is a magnetic collecting core including a first portion, a second portion continuous with the first end of the first portion, and a third portion continuous with the second end of the first portion, the first end and the second end are ends that are spaced apart from each other and facing each other in a second direction perpendicular to the first direction, the second portion and the third portion are each continuous with the first end and the second end along the first direction and the third direction perpendicular to the second direction, the magnetic detection unit is located in the core gap sandwiched between the second portion and the third portion, the second soft magnetic material includes a first magnetic shield and a second magnetic shield that are positioned to overlap the core gap when viewed along the third direction, and the magnetic detection unit may be positioned sandwiched between the first magnetic shield and the second magnetic shield. The detected magnetic flux may be generated by an electric current flowing through a conductor.

[0016] The present invention provides a correction circuit for correcting the output from the magnetic sensor, comprising a correction unit for correcting a hysteresis error due to the residual magnetic flux of the soft magnetic material included in the physical quantity detected by the magnetic detection unit, wherein 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.

[0017] In the above-described correction circuit, the correction unit may correct the hysteresis error using the following formulas (1) to (4).

[0018]

number

[0019] The present invention provides a magnetic sensor module characterized by having the above-mentioned magnetic sensor and the above-mentioned correction circuit. The present invention provides an electrical control device characterized by comprising the above-mentioned magnetic sensor, and an electrical control device characterized by comprising the above-mentioned magnetic sensor module.

[0020] The present invention provides a method for correcting the physical quantity detected by the magnetic sensor, the method including: a step of obtaining a first output value from the first magnetic detection unit and a second output value from the second magnetic detection unit; and a step of correcting a hysteresis error due to the residual magnetic flux of the soft magnetic material included in the physical quantity detected by the magnetic detection unit based on the first output value and the second output value, thereby obtaining the corrected physical quantity.

[0021] In the above correction method, the hysteresis error can be corrected by the following mathematical formulas (1) to (4).

[0022]

Equation

Advantages of the Invention

[0023] According to the present invention, it is possible to provide a magnetic sensor, a correction circuit, a magnetic sensor module, an electric control device, and a correction method capable of correcting a hysteresis error due to residual magnetic flux from a soft magnetic material.

Brief Description of the Drawings

[0024] [Figure 1] FIG. 1 is a perspective view showing a schematic configuration of a current sensor in an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing a schematic configuration of a current sensor in an embodiment of the present invention as a cut end face. [Figure 3] FIG. 3 is a schematic diagram showing a schematic configuration of a current sensor in an embodiment of the present invention as a cut end face. [Figure 4] FIG. 4 is a schematic diagram showing a schematic configuration of a current sensor in an embodiment of the present invention as a cut end face. [Figure 5] FIG. 5 is a schematic diagram showing a schematic configuration of a current sensor in an embodiment of the present invention as a cut end face. [Figure 6]Figure 6 is a schematic diagram showing the general configuration of a current sensor in one embodiment of the present invention, as seen from a cross-section. [Figure 7] Figure 7 is a schematic diagram showing the general configuration of a current sensor in one embodiment of the present invention, as seen from a cross-section. [Figure 8] Figure 8 is a perspective view showing a schematic configuration of a current sensor in one embodiment of the present invention. [Figure 9] Figure 9 is a block diagram showing a schematic configuration of a current sensor in one embodiment of the present invention. [Figure 10] Figure 10 is a block diagram showing an example configuration of an electrical control device in one embodiment of the present invention. [Modes for carrying out the invention]

[0025] A magnetic sensor according to an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a current sensor is used as an example of a magnetic sensor, but the magnetic sensor according to this embodiment is not limited to a current sensor.

[0026] In describing this embodiment, the terms "first direction, second direction, and third direction" are defined in some drawings as needed. Here, the first direction is the direction of the current flowing through the conductor. The second direction is perpendicular to the first direction and is the width direction of the conductor. The third direction is perpendicular to both the first and second directions and is the thickness direction of the conductor. In this specification and drawings, the first direction may be referred to as the "Z direction," the second direction as the "X direction," and the third direction as the "Y direction."

[0027] As shown in Figures 1 to 4, the current sensor 1 in this embodiment comprises a magnetic detection unit 2 capable of detecting magnetic flux, a magnetic collecting core 3 (first soft magnetic material), a magnetic shield 4 (second soft magnetic material), and a conductor 5 through which current flows in the Z direction.

[0028] The magnetic collecting core 3 is a soft magnetic material that focuses the magnetic flux generated by the flow of current through the conductor 5 so that the magnetic flux passes through it. The magnetic collecting core 3 is provided so as to surround the conductor 5 along the XY plane perpendicular to the Z direction. Surrounding the conductor 5 is a concept that includes not only an annular shape that encircles the conductor 5, but also a shape in which a part of the periphery of the conductor 5 and a part facing it are missing, a so-called C-shaped core. The magnetic collecting core 3 includes a first core portion 31, a second core portion 32, a third core portion 33, a fourth core portion 34, and a fifth core portion 35. The first core portion 31, the fourth core portion 34, and the fifth core portion 35 all extend in the X direction, which is the width direction of the conductor 5, for example. The second core portion 32 and the third core portion 33 all extend in the Y direction, which is the thickness direction of the conductor 5, for example. The first core portion 31 and the fourth core portion 34 and the fifth core portion 35 are arranged to face each other in the Y direction. The second core portion 32 and the third core portion 33 are arranged to face each other in the X direction. The second core portion 32 is provided to connect the first end portion 311 of the first core portion 31 in the X direction and the first end portion 341 of the fourth core portion 34 in the X direction. The second end portion 342 of the fourth core portion 34, opposite to the first end portion 341 in the X direction, has a first end face S34. The third core portion 33 is provided to connect the second end portion 312 of the first core portion 31 in the X direction and the first end portion 351 of the fifth core portion 35 in the X direction. The second end portion 352 of the fifth core portion 35, opposite to the first end portion 351 in the X direction, has a second end face S35. The first end face S34 and the second end face S35 are spaced apart from each other and face each other in the X direction. The space between the first end face S34 and the second end face S35 is the core gap CG. The core gap CG has a predetermined width in the X direction. Although Figures 1 to 6 show an embodiment in which the first core portion 31, the second core portion 32, the third core portion 33, the fourth core portion 34, and the fifth core portion 35 are connected in physical contact with each other, the magnetic collecting core 3 in this embodiment is not limited to this embodiment. For example, the first core portion 31, the second core portion 32, the third core portion 33, the fourth core portion 34, and the fifth core portion 35 do not need to be in physical contact with each other as long as they are magnetically connected to each other.

[0029] In this embodiment, the continuous portions of the first core portion 31 and the second core portion 32, the continuous portions of the first core portion 31 and the third core portion 33, the continuous portions of the second core portion 32 and the fourth core portion 34, and the continuous portions of the third core portion 33 and the fifth core portion 35 of the magnetic collecting core 3 all have a curved shape (rounded corner shape), but the embodiment is not limited to this. For example, these continuous portions may have a bent shape (shape with corners), or they may have a chamfered shape with beveled corners.

[0030] 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 portion 34 and the second end face S35 of the fifth core portion 35) can be set appropriately so that the current sensor 1 can exhibit the desired characteristics, for example, it should be 6 mm or more.

[0031] 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 provided in or near the core gap CG. When current flows through the conductor 5, a magnetic flux is generated from the conductor 5, and this magnetic flux is focused on the magnetic collecting core 3 having the core gap CG. Because the magnetic collecting core 3 is annular with a core gap CG, the entire magnetic collecting core 3, including the core gap CG, becomes a path for the magnetic flux (magnetic path). The magnetic flux focused on the magnetic collecting core 3 is the detected magnetic flux applied to the magnetic detection unit 2, and includes a first detected magnetic flux B1 applied to the first magnetic detection unit 21 and a second detected magnetic flux B2 applied to the second magnetic detection unit 22. In this invention, "magnetic flux" and "magnetic flux density" are substantially synonymous, so "magnetic flux" can be replaced with "magnetic flux density".

[0032] The first magnetic flux B1 applied to the first magnetic detection unit 21 and the second magnetic flux B2 applied to the second magnetic detection unit 22 are different (B1 ≠ B2). In other words, the first magnetic detection unit 21 and the second magnetic detection unit 22 are positioned such that different magnetic fluxes (first magnetic flux B1 and second magnetic flux B2) are applied to them, respectively. Preferably, the first magnetic detection unit 21 is provided at the position where the magnetic flux generated by the flow of current through the conductor 5 and focused on the magnetic collecting core 3 is at its maximum (maximum efficiency position), and the second magnetic detection unit 22 is provided at a position other than the maximum efficiency position. For example, as shown in Figures 1 and 2, the first magnetic detection unit 21 and the second magnetic detection unit 22 are provided within the core gap CG at positions where their lengths in the Y direction from the conductor 5 are different, and the first magnetic detection unit 21 may be provided at the maximum efficiency position. Furthermore, as shown in Figures 5 and 6, the first magnetic detection unit 21 may be located at the position of maximum efficiency within the core gap, while the second magnetic detection unit 22 may be located outside the core gap CG.

[0033] The magnetic shield 4 includes a first magnetic shield 41 and a second magnetic shield 42 that overlap the core gap CG when viewed along the Y direction. The second magnetic shield 42 is located closer to the conductor 5 than the first magnetic shield 41. When viewed along the Y direction, the magnetic detection unit 2 (first magnetic detection unit 21 and second magnetic detection unit 22) is positioned between the first magnetic shield 41 and the second magnetic shield 42. The first magnetic shield 41 and the second magnetic shield 42 are connected in the +Z direction via a third magnetic shield 43. That is, when viewed along the X direction, the magnetic shield 4 has a substantially U-shape (C-shape).

[0034] The magnetic collecting core 3 and magnetic shield 4 can both be made of soft magnetic materials such as silicon steel, electrical steel, pure iron (SUY), or permalloy, but silicon steel, electrical steel, or pure iron are preferred from the viewpoint of cost reduction. The iron loss of the constituent materials of the magnetic shield 4 should be greater than the iron loss of the constituent materials of the magnetic collecting core 3. When a predetermined current flows through the conductor 5, the magnetic flux generated from the conductor 5 is focused on the magnetic collecting core 3 and magnetic shield 4. When the frequency of the current flowing through 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 focused on the magnetic shield 4 decreases relatively. The frequency characteristics of the magnetic collecting core 3, which is made of a material with relatively low iron loss, also deteriorate, and it becomes more difficult to focus the magnetic flux, but the magnetic flux focused on the magnetic collecting core 3 increases relatively as the magnetic flux focused on the magnetic shield 4 decreases relatively. As a result, the detected magnetic flux applied to the magnetic detection unit 2 is considered to be more stable compared to the current sensor 1 without the magnetic shield 4, and the response characteristics of the current sensor 1 to the AC current can be stabilized. The constituent material of the magnetic collecting core 3 may be the same type of material as the constituent material of the magnetic shield 4, or it may be a different type of material, as long as the iron loss is smaller than that of the constituent material of the magnetic shield 4. For example, both the magnetic collecting core 3 and the magnetic shield 4 are made of electromagnetic steel, but it is sufficient that the iron loss of the electromagnetic steel constituting the magnetic shield 4 is greater than the iron loss of the electromagnetic steel constituting the magnetic collecting core 3.

[0035] The conductor 5, made of copper or the like, is a plate-like body with its longitudinal direction substantially parallel to the Z direction and its thickness direction substantially parallel to the Y direction, and is provided penetrating the ring-shaped magnetic collecting core 3 having a core gap CG in the Z direction. The longitudinal 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) intersects the Z direction at an angle of 2° or less. The thickness direction of the conductor 5 only needs to be substantially parallel to the Y direction; for example, it intersects the Y direction at an angle of 2° or less.

[0036] When an electric current flows through the conductor 5, the magnetic flux generated from the conductor 5 is focused onto the magnetic collecting core 3, which has a core gap CG. Because the magnetic collecting core 3 is annular in shape with a core gap CG, the entire magnetic collecting core 3, including the core gap CG and the magnetic shield 4, constitutes a path for the magnetic flux (magnetic path). The magnetic flux generated from the conductor 5 varies depending on the distance from the conductor 5. In the embodiments shown in Figures 1 to 6, the first magnetic detection unit 21 and the second magnetic detection unit 22 are positioned to which different detection magnetic fluxes (first detection magnetic flux B1 and second detection magnetic flux B2) are applied.

[0037] When an electric current flows through the conductor 5 and a magnetic flux is generated from the conductor 5, the magnetic collecting core 3 and magnetic shield 4, which are made of soft magnetic material, become magnetized. Even when no magnetic flux is generated from the conductor 5, i.e., when no electric current flows through the conductor 5 (zero magnetic field state), the magnetic collecting core 3 and magnetic shield 4 remain magnetized and have residual magnetization M, generating residual magnetic flux. The residual magnetic flux from the magnetic collecting core 3 and magnetic shield 4 is applied to the magnetic detection unit 2, which can cause a hysteresis error 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, the magnetic flux in the +X direction generated from the magnetic collecting core 3. The second residual magnetic flux Br2 is, for example, the magnetic flux in the -X direction generated from the magnetic shield 4. The first remanent magnetic flux Br1 and the second remanent magnetic flux Br2 are different from each other (Br1 ≠ Br2). In other words, the first magnetic detection unit 21 and the second magnetic detection unit 22 Each of them is positioned at a different location from the other, so that the first magnetic detection unit 21 and the second magnetic detection unit 22 Each teeth Different residual magnetic fluxes (first residual magnetic flux Br1 and second residual magnetic flux Br2) are applied. The residual magnetic fluxes can interfere within the region sandwiched between the first magnetic shield 41 and the second magnetic shield 42 in the core gap CG. That is, in the embodiment shown in Figure 1, this region can be described as a magnetic flux interference region where the first residual magnetic flux Br1 and the second residual magnetic flux Br2 interfere with each other. Then, the first magnetic detection unit 21 and the second magnetic detection unit 22 each... In the region of magnetic flux interference, different That rank PlaceBy doing so, the ratio of the first remanent magnetic flux Br1 to the first detected magnetic flux B1 (Br1 / B1) and the ratio of the second remanent magnetic flux Br2 to the second detected magnetic flux B2 (Br2 / B2) are obtained. They are different from each other. This makes it possible to correct hysteresis errors that may occur when the first magnetic detection unit 21 and the second magnetic detection unit 22 detect residual magnetic flux.

[0038] In the current sensor 1 having the configuration described above, the magnetic flux generated by the flow of current through the conductor 5 is focused on the magnetic collecting core 3. The flow of magnetic flux focused on the magnetic collecting core 3 forms an annular 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. The first magnetic detection unit 21 is provided at a position where a first residual magnetic flux Br1 is applied, and the second magnetic detection unit 22 is provided at a position where a second residual magnetic flux Br2, which has a different magnetic flux density from the first residual magnetic flux Br1, is applied. As a result, as will be described later, hysteresis errors that may occur when the first magnetic detection unit 21 and the second magnetic detection unit 22 detect residual magnetic flux can be corrected. Therefore, the current sensor 1 in this embodiment can detect the current flowing through the conductor 5 with high accuracy.

[0039] As shown in Figure 9, the current sensor 1 in this embodiment may include a signal processing unit 6. The signal processing unit 6 may include an A / D (analog-to-digital) conversion unit 61 that converts the analog signal output from the magnetic detection unit 2 into a digital signal, and a calculation unit 62 that performs calculations on the digital signal converted by the A / D conversion unit 61. If the calculation results processed by the calculation unit 62 are to be output as an analog signal, the signal processing unit 6 may further include a D / A (digital-to-analog) conversion unit (not shown) downstream of the calculation unit 62. In this embodiment, the current sensor 1 may also constitute a current sensor module together with the signal processing unit 6.

[0040] In this embodiment, the magnetic detection unit 2 may include, for example, one element unit, or it may include multiple element units (for example, first to fourth element units). If multiple element units are included, a Wheatstone bridge circuit (a full bridge circuit by the first to fourth element units, or a half-bridge circuit by the first and second element units) may be formed by the multiple 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.

[0041] The A / D conversion unit 61 converts the sensor signal (analog signal related to current) output from the current sensor 1 into a digital signal, and this digital signal is input to the calculation unit 62. The calculation unit 62 performs correction processing to correct hysteresis errors contained in the digital signal converted from the analog signal by the A / D conversion unit 61, and also performs calculation processing. This calculation unit 62 is composed of, for example, a microcomputer, an ASIC (Application Specific Integrated Circuit), etc. In this embodiment, the calculation unit 62 or the signal processing unit 6 including the calculation unit 62 constitutes the correction circuit.

[0042] The hysteresis error correction process in the calculation unit 62 will now be explained. Let "a" be the conversion rate for converting the first detected magnetic flux B1 applied to the first magnetic detection unit 21 into a current value, and let "b" be the conversion rate for converting the second detected magnetic flux B2 applied to the second magnetic detection unit 22 into a current value. The conversion rate a is expressed as the ratio of the maximum rated value Im of the current value obtained from the output of the first magnetic detection unit 21 to the maximum rated value Bm1 of the first detected magnetic flux B1 applied to the first magnetic detection unit 21. The conversion rate b is expressed as the ratio of the maximum rated value Im of the current value obtained from the output of the second magnetic detection unit 22 to the maximum rated value Bm2 of the second detected magnetic flux B2 applied to the second magnetic detection unit 22. In relation to the first detected magnetic flux B1, the second detected 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 determined by the following formulas (5) and (6).

[0043]

number

[0044] Then, if we define "Δ" as 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, the difference Δ can be calculated using the following formula (7).

[0045]

number

[0046] In the above formula (7), "a × B1" and "b × B2" represent the true current I flowing through the conductor 5, which is determined when the first residual magnetic flux Br1 and the second residual magnetic flux Br2 are not applied to the first magnetic detection unit 21 and the second magnetic detection unit 22. exp Therefore, a × B1 = b × B2 = I exp It can be said that...

[0047] In the above formula (7), "a × Br1 - b × Br2" represents a value that depends on the magnetization state of the magnetic core 3 and magnetic shield 4, which are made of soft magnetic material. Here, the current value I' obtained by subtracting the difference Δ multiplied by a constant K from the current value I1 obtained from the output of the first magnetic detection unit 21 is expressed by the following formulas (8) and (9).

[0048]

number

[0049] In the above equation (8), since there are no terms relating to the first remanent magnetic flux Br1 and the second remanent magnetic flux Br2, it can be understood that the current value I' does not include the hysteresis error that may occur due to the remanent magnetic flux. Then, the true current value I flowing through conductor 5 is calculated by subtracting the above current value I' from the true current value I exp By pre-determining the conversion factor c, the true current value I flowing through conductor 5 can be calculated using the following formula (10): exp This may be required.

[0050]

number

[0051] The constant K and coefficient c mentioned above can be calculated in advance using an accurate measurement system with 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 detected magnetic flux (maximum rated value Bm1) detected by the first magnetic detection unit 21, the first residual magnetic flux Br1max, the second detected magnetic flux (maximum rated value Bm2) detected by the second magnetic detection unit 22, and the second residual magnetic flux Br2max, when a current of maximum rated value Im flows through the conductor 5.

[0052]

number

[0053] Thus, in the current sensor 1 of this embodiment, the first magnetic detection unit 21 and the second magnetic detection unit 22 are provided on magnetic flux loops with different magnetic flux densities. The first magnetic detection unit 21 is provided at a position where a first residual magnetic flux Br1 is applied, and the second magnetic detection unit 22 is provided at a position where a second residual magnetic flux Br2, which is different from the first residual magnetic flux Br1, is applied. As a result, the hysteresis error included in the output from the current sensor 1 can be corrected using the following formulas (1) to (4), and the true current value I exp It can detect them with high accuracy.

[0054]

number

[0055] The current sensor 1 in this embodiment may be provided in an electrical control device. Examples of electrical control devices in this embodiment include battery management systems for hybrid electric vehicles (HEVs) and electric vehicles (EVs), inverters, and converters. The current sensor 1 in this embodiment is used to measure the input and output current from a power supply and to output information about the measured current to the electrical control device. As shown in Figure 10, for example, the electrical control device 10 may include the current sensor 1, a power supply 11, and a control circuit 12. The current sensor 1 detects the current output from or input to the power supply 11. Information about the current value detected by the current sensor 1 is transmitted to the control circuit 12. The control circuit 12 controls, for example, the operation of the current sensor 1 and the operation of the power supply 11. The control circuit 12 adjusts the output current from the power supply 11 based on the information from the current sensor 1.

[0056] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit it. Accordingly, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0057] In the above embodiment, the magnetic collecting core 3 was described as including a first core portion 31, a second core portion 32, a third core portion 33, a fourth core portion 34, and a fifth core portion 35 as an example, but the embodiment is not limited to this. For example, as shown in Figures 5 and 6, the magnetic collecting core 3 may include a first core portion 31, a second core portion 32, and a third core portion 33, but not include a fourth core portion 34 and a fifth core portion 35. In this case, the first magnetic detection unit 21 may be provided in 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 may be provided outside the core gap CG, at a position further from the conductor 5 than the first magnetic detection unit 21 along the Y direction (see Figure 5), or it may be provided between the end of the second core portion 32 and the magnetic shield 4 (see Figure 6). Alternatively, as shown in Figure 7, for example, the magnetic collecting core 3 may be omitted, and the conductor 5 and the first magnetic detection unit 21 and the second magnetic detection unit 22 may be sandwiched between two magnetic shields 4, 4.

[0058] In the above embodiment, an example was described in which the current sensor comprises one magnetic collecting core 3 and two magnetic detection units 2 (a first magnetic detection unit 21 and a second magnetic detection unit 22), but the current sensor is not limited to this embodiment. For example, as shown in Figure 8, the current sensor 1 may comprise a first magnetic collecting core 3A and a second magnetic collecting core 3B made of different types of soft magnetic materials, with the first magnetic detection unit 21 provided in the core gap CG1 of the first magnetic collecting core 3A and the second magnetic detection unit 22 provided in the core gap CG2 of the second magnetic collecting core 3B. In this case, it is sufficient that the residual magnetic flux of the soft magnetic material constituting the first magnetic collecting core 3A and the residual magnetic flux of the soft magnetic material constituting the second magnetic collecting core 3B are different. For example, the soft magnetic material constituting the first magnetic collecting core 3A may be a silicon steel plate with a relatively large residual magnetic flux, and the soft magnetic material constituting the second magnetic collecting core 3B may be permalloy with a relatively small residual magnetic flux.

[0059] In the above embodiment, a current sensor 1 for detecting the current flowing through the conductor 5 was used as an example, but the embodiment is not limited to this. For example, a magnetic sensor for detecting the position of a moving body that is moving linearly or rotating may also be used. [Examples]

[0060] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to the examples described below.

[0061] [Example Test] Using a current sensor 1 having the configuration shown in Figures 1 and 2, the current value flowing through the conductor 5 was varied within the range of 20 to 600 A, and the hysteresis error included in the output of the current sensor 1 was determined. As a result, it was confirmed that by performing hysteresis error correction processing by the calculation unit 62, a reduction effect of more than 80% in hysteresis error could be obtained compared to when no correction processing was performed. [Explanation of Symbols]

[0062] 1…Current sensor 2...Magnetic detection unit 21...First magnetic detection unit 22...Second magnetic detection unit 3… Magnetic collecting core 4…Magnetic shielding 5...Conductor

Claims

1. A first soft magnetic material and a second soft magnetic material from which the magnetic flux is focused, A first magnetic detection unit that can detect at least a portion of the magnetic flux focused on the first soft magnetic material and the second soft magnetic material as a first detected magnetic flux when the magnetic flux can be focused on the first soft magnetic material and the second soft magnetic material, and can detect at least a portion of the magnetic flux remaining in the first soft magnetic material and the second soft magnetic material as a first residual magnetic flux when the magnetic flux cannot be focused on the first soft magnetic material and the second soft magnetic material, A second magnetic detection unit that can detect at least a portion of the magnetic flux focused on the first soft magnetic material and the second soft magnetic material as a second detectable magnetic flux when the magnetic flux can be focused on the first soft magnetic material and the second soft magnetic material, and can detect at least a portion of the magnetic flux remaining in the first soft magnetic material and the second soft magnetic material as a second remanent magnetic flux when the magnetic flux cannot be focused on the first soft magnetic material and the second soft magnetic material, The system includes a correction unit that corrects the signals based on the detection results of the first magnetic detection unit and the second magnetic detection unit, The first magnetic detection unit and the second magnetic detection unit are each positioned at different locations within the magnetic flux interference region where the first remanent magnetic flux and the second remanent magnetic flux interfere with each other. The ratio of the first remanent magnetic flux to the first detected magnetic flux is different from the ratio of the second remanent magnetic flux to the second detected magnetic flux. The correction unit calculates the difference between a first output value, which is the output value of the first magnetic detection unit based on the first detected magnetic flux and the first remanent magnetic flux, and a second output value, which is the output value of the second magnetic detection unit based on the second detected magnetic flux and the second remanent magnetic flux, and corrects the hysteresis error caused by at least one of the first remanent magnetic flux and the second remanent magnetic flux due to the first soft magnetic material and the second soft magnetic material based on this difference, and is characterized by being a magnetic sensor.

2. The magnetic sensor according to claim 1, characterized in that the first residual magnetic flux and the second residual magnetic flux are different.

3. The magnetic sensor according to claim 1 or 2, characterized in that the first detected magnetic flux and the second detected magnetic flux are different.

4. The magnetic sensor according to any one of claims 1 to 3, characterized in that the correction unit calculates a current in which the hysteresis error has been corrected using a constant K determined in advance by the following formulas (1) to (4) and formula (11). [Math 1] [Math 2] In the above formulas (1) to (4), I ｅｘｐ is the "corrected current", c is the "conversion factor", Δ is the "difference between the first output value and the second output value", I １ is "First output value", Br １ is the "first residual magnetic flux", Br ２ B is the "second residual magnetic flux". １ B is the "first detected magnetic flux". ２ represents the "second detected magnetic flux," a represents the "conversion rate for converting the first detected magnetic flux into electric current," and b represents the "conversion rate for converting the second detected magnetic flux into electric current." In the above formula (11), K represents "constant", Im represents "maximum value of current", and when the current at the maximum rated value flows through the conductor, Bm １ represents "maximum rated value of the first detected magnetic flux", Br １ max represents "maximum rated value of the first residual magnetic flux", Bm ２ represents "maximum rated value of the second detected magnetic flux", Br ２ max represents "maximum rated value of the second residual magnetic flux".

5. The first soft magnetic material is a magnetic collecting core including a first portion, a second portion continuous with the first end of the first portion, and a third portion continuous with the second end of the first portion. The two ends of the first soft magnetic material are spaced apart from each other and facing each other in a second direction perpendicular to the first direction which is the direction in which the current that generates the magnetic flux flows when the magnetic flux can be focused on the first soft magnetic material and the second soft magnetic material. The second and third portions are continuous with the first and second ends, respectively, along a third direction perpendicular to the first and second directions. At least one of the first magnetic detection unit and the second magnetic detection unit is located in the core gap sandwiched between the second and third portions. The second soft magnetic material includes a first magnetic shield and a second magnetic shield positioned to overlap the core gap when viewed along the third direction, The magnetic sensor according to any one of claims 1 to 4, characterized in that the first magnetic detection unit and the second magnetic detection unit are positioned between the first magnetic shield and the second magnetic shield.

6. The magnetic sensor according to claim 5, characterized in that the magnetic flux interference region is a region sandwiched between the first magnetic shield and the second magnetic shield in the core gap.

7. The magnetic sensor according to any one of claims 1 to 6, wherein each of the first detected magnetic flux and the second detected magnetic flux is generated by the flow of current through a conductor.

8. A correction circuit comprising a magnetic sensor according to any one of claims 1 to 7.

9. A magnetic sensor module characterized by having a magnetic sensor according to any one of claims 1 to 7.

10. An electrical control device characterized by comprising a magnetic sensor according to any one of claims 1 to 7.

11. An electrical control device characterized by comprising the magnetic sensor module described in claim 9.

12. A first soft magnetic material and a second soft magnetic material from which the magnetic flux is focused, A first magnetic detection unit that can detect at least a portion of the magnetic flux focused on the first soft magnetic material and the second soft magnetic material as a first detected magnetic flux when the magnetic flux can be focused on the first soft magnetic material and the second soft magnetic material, and can detect at least a portion of the magnetic flux remaining in the first soft magnetic material and the second soft magnetic material as a first residual magnetic flux when the magnetic flux cannot be focused on the first soft magnetic material and the second soft magnetic material, A second magnetic detection unit detects at least a portion of the magnetic flux focused on the first soft magnetic material and the second soft magnetic material as a second detected magnetic flux when the magnetic flux can be focused on the first soft magnetic material and the second soft magnetic material, and detects at least a portion of the magnetic flux remaining in the first soft magnetic material and the second soft magnetic material as a second residual magnetic flux when the magnetic flux cannot be focused on the first soft magnetic material and the second soft magnetic material. The system includes a correction unit that corrects the signals based on the detection results of the first magnetic detection unit and the second magnetic detection unit, The first magnetic detection unit and the second magnetic detection unit are each positioned at different locations within the magnetic flux interference region where the first remanent magnetic flux and the second remanent magnetic flux interfere with each other. A correction method for correcting a magnetic sensor signal in which 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, A correction method characterized in that the correction unit calculates the difference between a first output value, which is the output value of the first magnetic detection unit based on the first detected magnetic flux and the first remanent magnetic flux, and a second output value, which is the output value of the second magnetic detection unit based on the second detected magnetic flux and the second remanent magnetic flux, and corrects the hysteresis error caused by at least one of the first remanent magnetic flux and the second remanent magnetic flux by the first soft magnetic material and the second soft magnetic material based on this difference.

13. The correction method according to claim 12, characterized in that the current corrected for the hysteresis error is calculated using a constant K obtained in advance by the following formulas (1) to (4) and formula (11). [Math 3] [Math 4] In the above formulas (1) to (4), I ｅｘｐ is the "corrected current", c is the "conversion factor", Δ is the "difference between the first output value and the second output value", I １ is "First output value", Br １ is the "first residual magnetic flux", Br ２ B is the "second residual magnetic flux". １ B is the "first detected magnetic flux". ２ represents the "second detected magnetic flux," a represents the "conversion rate for converting the first detected magnetic flux into electric current," and b represents the "conversion rate for converting the second detected magnetic flux into electric current." In the above formula (11), K represents a "constant", Im represents the "maximum value of the current", and Bm １ Br is defined as the "maximum rated value of the first detected magnetic flux" when the current of the maximum rated value flows through the conductor. １ max is the "maximum rated value of the first residual magnetic flux" when the maximum rated current flows through the conductor, Bm ２ Br is defined as the "maximum rated value of the second detected magnetic flux" when the current of the maximum rated value flows through the conductor. ２ 'max' represents the "maximum rated value of the second residual magnetic flux" when the maximum rated current flows through the conductor.

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