CN116449073A

CN116449073A - Current sensor, electrical control device, current sensor module, and method for producing same

Info

Publication number: CN116449073A
Application number: CN202310066123.4A
Authority: CN
Inventors: 冈祯一郎; 平野裕幸; 毛受良一; 高桥真; 木槫隼人
Original assignee: TDK Corp
Current assignee: TDK Corp
Priority date: 2022-01-17
Filing date: 2023-01-16
Publication date: 2023-07-18
Also published as: JP2023104335A

Abstract

The current sensor of the present invention includes a magnetic detection unit and a first soft magnetic body. The magnetic detection portion is applied with magnetic flux in a second direction, which is generated by current flowing through the conductor in the first direction. The first soft magnetic body has a bottom portion, a first wall portion, and a second wall portion, the bottom portion being located on a side opposite to the conductor as viewed from the magnetic detection portion in a third direction orthogonal to the first direction, the first wall portion and the second wall portion being respectively erected on the bottom portion and facing the magnetic detection portion with the conductor interposed therebetween in the second direction.

Description

Current sensor, electrical control device, current sensor module, and method for producing same

Technical Field

The invention relates to a current sensor, an electrical control device, a current sensor module and a manufacturing method thereof.

Background

In recent years, current sensors have been used for measurement of remaining battery power of hybrid Electric vehicles (HEV: hybrid Electric Vehicle) and Electric Vehicles (EV), measurement of driving current of Electric motors, and power control devices such as converters and inverters. As a current sensor, a magnetic current sensor including a magnetic detection element capable of detecting a magnetic field generated by a current flowing through a primary conductor such as a bus bar is known. The magnetic current sensor includes, as magnetic detection elements, magnetoresistive effect elements such as AMR (Anisotropic Magneto Resistive effect) element, GMR (Giant Magneto Resistive effect) element, and TMR (Tunnel Magneto Resistive effect) element, hall element, and the like. In the current sensor, the magnetic resistance element and the magnetic detection element can detect the current flowing through the primary conductor such as the bus bar in a non-contact state.

For example, patent document 1 discloses a current sensor including: an annular magnetic core having a gap (clearance) and a magnetic sensor including a magnetic detection element disposed in the gap. In the current sensor of patent document 1, the magnetic flux generated from the conductor can be concentrated on the magnetic core, and the magnetic flux concentrated on the magnetic core can be applied to the magnetic detection element disposed in the gap.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2019-78542

Disclosure of Invention

However, for a current sensor having a magnetic sensor, it is desirable to have high measurement accuracy and to be able to be easily mounted by a mounting place.

Accordingly, it is desirable to provide a current sensor that has high measurement accuracy and can be easily mounted by a mounting portion.

The current sensor according to an embodiment of the present invention includes a magnetic detection unit and a first soft magnetic body. The magnetic detection portion is applied with magnetic flux in a second direction, which is generated by current flowing through the conductor in the first direction. The first soft magnetic body has a bottom portion located on the opposite side of the conductor from the magnetic detection portion in a third direction orthogonal to the first direction, and a pair of wall portions each standing on the bottom portion and facing the magnetic detection portion with the conductor therebetween in the second direction.

An electrical control device and a current sensor module according to an embodiment of the present invention include a current sensor according to the above-described embodiment.

A method for manufacturing a current sensor module according to an embodiment of the present invention is a method for manufacturing a current sensor module including a conductor, a magnetic detection unit, a first soft magnetic body, and a case. The magnetic detection portion is applied with a magnetic flux in a second direction generated by a current flowing through the conductor in the first direction. The manufacturing method of the current sensor module comprises the following steps: preparing a first soft magnetic body having a bottom portion, a first wall portion and a second wall portion, the bottom portion being expanded in a first direction and a second direction, the first wall portion and the second wall portion being respectively erected on the bottom portion and facing the magnetic detection portion with the conductor therebetween in the second direction; preparing a housing including a pair of recesses arranged in a first direction and provided with a first soft magnet and a magnetic detection portion; the conductors are fitted in the pair of recesses.

According to the current sensor as an embodiment of the present invention, the conductor through which the current to be detected flows can be attached without changing the relative position between the magnetic detection unit and the first soft magnetic body. Therefore, high measurement accuracy can be ensured, and the mounting can be simplified. The effects of the present invention are not limited to this, and may be any of the effects described below.

Drawings

Fig. 1 is a perspective view showing an example of the overall structure of a current sensor according to a first embodiment of the present invention.

Fig. 2 is a schematic perspective view of the main part of the current sensor shown in fig. 1 and a conductor.

Fig. 3 is a schematic cross-sectional view of the current sensor shown in fig. 1.

Fig. 4 is a block diagram showing a schematic configuration of the magnetic detection unit shown in fig. 1.

Fig. 5 is a schematic circuit diagram showing a circuit configuration of the magnetic detection element unit shown in fig. 4.

Fig. 6 is a schematic cross-sectional view of a current sensor as a first modification of the first embodiment of the present invention.

Fig. 7 is a schematic cross-sectional view of a current sensor as a second modification of the first embodiment of the present invention.

Fig. 8 is a schematic cross-sectional view of a current sensor as a third modification of the first embodiment of the present invention.

Fig. 9 is a schematic cross-sectional view of a current sensor as a fourth modification of the first embodiment of the present invention.

Fig. 10 is a schematic cross-sectional view of a current sensor as a fifth modification of the first embodiment of the present invention.

Fig. 11 is a block diagram showing a configuration example of an electric control device according to a second embodiment of the present invention.

Fig. 12 is a schematic cross-sectional configuration of the current sensor of embodiment 1-1 of the present invention.

FIG. 13 is an explanatory view illustrating examples 1-1 to 1-5 of the present invention.

FIG. 14 is an explanatory view illustrating examples 2-1 to 2-3 of the present invention.

FIG. 15 is an explanatory view illustrating examples 3-1 to 3-2 of the present invention.

FIG. 16 is an explanatory view illustrating examples 4-1 to 4-2 of the present invention.

Symbol description

1. Current sensor

2. Magnetic detection unit

20. Magnetic detection element part

60. Signal processing unit

3. Shell body

4. Magnetic shielding body

41. Bottom part

42A first wall portion

42B second wall portion

5. Conductor

6. Screw

7. Magnetic yoke

Bm magnetic flux

Im current

Detailed Description

Embodiments for carrying out the present invention are described in detail below with reference to the accompanying drawings. The following embodiments are all preferred examples of the present invention. Accordingly, the numerical values, shapes, materials, components, arrangement positions of components, connection modes, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Therefore, among the constituent elements of the following embodiments, constituent elements not described in the independent claims showing the uppermost concept of the present invention will be described as arbitrary constituent elements. The drawings are schematic and are not necessarily strict. In the drawings, substantially the same components are denoted by the same reference numerals, and overlapping description is omitted or simplified. The following procedure is described.

0. Background

1. First embodiment

An example of a current sensor disposed near a conductor.

2. Modification of the first embodiment

2.1 modification 1

2.2 modification 2

2.3 modification 3

2.4 modification 4

2.5 modification 5

3. Second embodiment

An example of an electrical control device provided with a current sensor.

4. Examples

<0. Background >

The measurement accuracy of a magnetic current sensor is affected by variations in the shapes and relative position of a primary conductor (bus bar) through which a current to be detected flows, a magnetic detection element, a yoke, and a magnetic shield. The measurement accuracy of the magnetic current sensor is also further affected by the sensitivity of the magnetic detection element and the magnetic characteristics of the yoke. Therefore, in order to achieve high measurement accuracy of the current sensor, it is necessary to adjust factors that affect the measurement accuracy, such as the deviation of the plurality of magnetic detection elements and the deviation of sensitivity, during the manufacturing process of the current sensor and the installation process of the current sensor. Currently, a mainstream method of adjusting such an element affecting measurement accuracy is performed electrically by, for example, an integrated circuit integrated with a magnetic detection element.

However, as a previous stage of such electric adjustment, it is desirable to fix the relative positions of the primary conductor, the magnetic detection element, and the magnetic shield (or the yoke). However, in the conventional magnetic current sensor, the primary conductor, the magnetic detection element, and the magnetic shield (or the yoke) are interposed therebetween. Therefore, it is necessary to insert the primary conductor into the opening of the current sensor in which the magnetic detection element and the magnetic shield (or the yoke) are integrated, and it is necessary to perform an operation such as partially removing the primary conductor once. Or, in the case where the primary conductor cannot be moved or the primary conductor cannot be partially removed, it is necessary for the user to electrically adjust the above-described elements that affect the measurement accuracy after individually disposing the magnetic detection element and the magnetic shield (or the yoke) so as to face each other with the primary conductor interposed therebetween. As described above, in the conventional current sensor, the program for setting the vicinity of the primary conductor is limited, and it is necessary for the user to perform electric adjustment or the like related to the measurement accuracy of the current sensor, and it is difficult to secure high measurement accuracy because of poor workability.

In view of the above problems, the present applicant has repeatedly studied and improved a current sensor having high measurement accuracy and capable of being easily mounted at a mounting position, and an electric control device including the current sensor.

<1 > first embodiment

[ Structure of current sensor 1 ]

First, a structure of a current sensor 1 according to a first embodiment of the present invention will be described with reference to fig. 1 to 3. Fig. 1 is a perspective view showing an example of the overall structure of a current sensor 1. As shown in fig. 1, the current sensor 1 includes, for example, a magnetic detection unit 2 and a magnetic shield 4. The current sensor 1 is disposed, for example, in the vicinity of the conductor 5. The conductor 5 extends in the Z-axis direction, for example. In the conductor 5, a current Im flows along the Z-axis direction, and the current Im is a detection target of the current sensor 1. The module provided with the current sensor 1 and the conductor 5 corresponds to the current sensor module of the present invention.

The current sensor 1 may further include a housing 3. The case 3 is made of an insulating material such as resin, for example, and includes a pair of recesses 31,32 aligned in the Z-axis direction in which the conductor 5 extends. The pair of recesses 31,32 are configured to be capable of fitting with the conductor 5. Holes are provided in the conductor 5 at positions corresponding to the pair of recesses 31,32, for example, and the conductor 5 is fixed to the pair of recesses 31,32 by a screw 6, for example. In addition, the magnetic detection portion 2 and the magnetic shield 4 are provided on the housing 3. A part of the magnetic shield 4 is buried in the case 3. Therefore, the conductor 5 is fixed to the housing 3, and the relative positions of the conductor 5 and the magnetic detection portion 2 and the magnetic shield 4 are fixed. The conductor 5 is electrically insulated from the magnetic detection portion 2 and the magnetic shield 4 by the housing 3. The magnetic detection unit 2 is a device driven with a low voltage, for example, about several V, with respect to the application of a high voltage, for example, several hundred V or more, to the conductor 5. However, the voltages applied to the conductor 5 and the magnetic detector 2 are not limited to the above voltages, and may be arbitrarily selected. In fig. 1, the conductor 5 is indicated by a broken line for the purpose of clearly showing the case 3 and the magnetic detection unit 2. In the present embodiment, the case where the conductor 5 is not included in the constituent elements of the current sensor 1 is exemplified.

Fig. 2 is a schematic perspective view of the main part of the current sensor 1 and the conductor 5. Specifically, fig. 2 shows the positional relationship between the conductor 5 and the magnetic detection portion 2 and the magnetic shield 4 in the current sensor 1, and the appearance of the magnetic shield 4. Fig. 3 is a schematic cross-sectional view of the XY plane of the current sensor 1 perpendicular to the Z axis direction. In fig. 2 and 3, illustration of the housing 3 is omitted.

As shown in fig. 3, in the current sensor 1, if the current Im flows through the conductor 5 in the +z direction along the Z-axis direction, a magnetic flux Bm is induced around the conductor 5. The magnetic flux Bm passes through the magnetic shield 4 and the inside of the magnetic detection section 2, for example. The magnetic flux Bm is applied to the magnetic detection section 2 in, for example, the +x direction along the X-axis direction. That is, when the current Im flows in the +z direction, the magnetic detection unit 2 is disposed at a position where the magnetic flux Bm passes in the +x direction. In the present embodiment, the direction along the width of the conductor 5 is defined as the X-axis direction, and the thickness direction of the conductor 5 is defined as the Y-axis direction. The "Z-axis direction", "X-axis direction", and "Y-axis direction" of the present embodiment are one specific example corresponding to the "first direction", "second direction", and "third direction" of the present invention, respectively.

(conductor 5)

The conductor 5 is made of a highly conductive nonmagnetic material such as Cu (copper). The conductor 5 is, for example, a substantially plate-like body extending in the Z-axis direction as a long direction and in the Y-axis direction as a thickness direction. The conductor 5 is disposed so as to be inserted into a space surrounded by the substantially U-shaped magnetic shield 4.

(magnetic shield 4)

The magnetic shield 4 magnetically protects the magnetic detection unit 2 from the disturbing magnetic field. That is, the magnetic shield 4 is a soft magnetic body, and can reduce the influence of an unnecessary magnetic field (magnetic flux) from the outside other than the magnetic flux Bm to be detected on the magnetic detection unit 2. The magnetic shield 4 plays a role of avoiding disturbance of the magnetic flux Bm induced by the current Im flowing through the conductor 5 by the disturbing magnetic field. As shown in fig. 3, the magnetic shield body 4 has a substantially U-shape as a whole in an XY section. The magnetic shield 4 is disposed apart from the conductor 5 without physical contact. The magnetic shield 4 is electrically insulated from the conductor 5.

The magnetic shield body 4 includes a bottom portion 41, a first wall portion 42A, and a second wall portion 42B. The bottom 41 is, for example, a plate-like portion extending along the XZ plane. The first wall portion 42A and the second wall portion 42B are, for example, plate-like portions each extending along the YZ plane. The first wall 42A and the second wall 42B are respectively erected on the bottom 41 and face the magnetic detection portion 2 with the conductor 5 interposed therebetween in the X-axis direction. The magnetic shield body 4 is made of a soft magnetic material such as silicon steel, electromagnetic steel, pure iron (SUY), permalloy, ferrite, or the like as a main constituent material. The magnetic shield body 4 is a specific example corresponding to the "first soft magnet" of the present invention. The bottom 41 is a specific example corresponding to the "bottom" of the present invention. The first wall portion 42A is a specific example corresponding to the "first wall portion" of the present invention. The second wall portion 42B is a specific example corresponding to the "second wall portion" of the present invention.

(magnetic detection section 2)

The magnetic detection portion 2 is provided between the conductor 5 and the bottom portion 41 of the magnetic shield body 4 in the Y-axis direction. That is, the magnetic detection portion 2 is provided at a position overlapping both the conductor 5 and the bottom portion 41 of the magnetic shield body 4 in the Y-axis direction. Therefore, the bottom 41 is located on the opposite side of the conductor 5 from the magnetic detection section 2 in the Y-axis direction. In the present embodiment, the center position of the magnetic detector 2 in the X-axis direction preferably coincides with the center position of the conductor 5 in the X-axis direction and coincides with the center position of the magnetic shield 4 in the X-axis direction. However, the present invention is not limited thereto. In fig. 3, the magnetic detection unit 2 is shown separately from the magnetic shield 4, but the magnetic detection unit 2 and the magnetic shield 4 may be in contact. However, the magnetic detection section 2 and the conductor 5 are separated from each other without physical contact and are electrically insulated from each other. The current Im flows through the conductor 5, and the magnetic flux Bm induced around the conductor 5 is applied to the magnetic detection unit 2. The magnetic detection unit 2 detects the magnitude and direction of the magnetic flux Bm. The detailed structure of the magnetic detection unit 2 will be described later.

In the current sensor 1, as shown in fig. 3, each of the first distance H42A from the bottom 41 to the first top 42AT of the first wall portion 42A and the second distance H42B from the bottom 41 to the second top 42BT of the second wall portion 42B may be 2 times or more the third distance H5 of the bottom 41 from the conductor 5. That is, the center position of the conductor 5 is located at a position less than half the height of the first wall portion 42A and less than half the height of the second wall portion 42B with reference to the upper surface of the bottom portion 41. This is because the influence of an unnecessary disturbing magnetic field (particularly, a disturbing magnetic field in the Y-axis direction) on the magnetic detection section 2 can be further reduced. In fig. 3, the case where the first distance H42A, which is the height of the first wall portion 42A, is equal to the second distance H42B, which is the height of the second wall portion 42B, is illustrated, but the present invention is not limited thereto. The first distance H42A and the second distance H42B may also be different.

Further, in the current sensor 1, as shown in fig. 3, the fourth distance H2 between the bottom 41 and the magnetic detection portion 2 may be less than half the third distance H5 between the bottom 41 and the conductor 5. This is because the shielding effect against the disturbing magnetic field of the magnetic detection unit 2 can be further improved.

Fig. 4 is a block diagram showing a schematic configuration of the magnetic detection unit 2. As shown in fig. 4, the magnetic detection unit 2 includes a magnetic detection element unit 20 and a signal processing unit 60. The signal processing section 60 includes, for example, an a/D (analog-digital) conversion section 61 and an arithmetic section 62. The a/D conversion section 61 converts the analog signal output from the magnetic detection element section 20 into a digital signal. The arithmetic unit 62 performs arithmetic processing on the digital signal digitally converted by the a/D conversion unit 61. The signal processing unit 60 may further include a D/a (digital-analog) conversion unit on the downstream side of the calculation unit 62. By including the D/a conversion unit, the signal processing unit 60 can output the result of the arithmetic processing by the arithmetic unit 62 as an analog signal.

Fig. 5 is a schematic circuit diagram showing the circuit configuration of the magnetic detection element unit 20 shown in fig. 4. As shown in fig. 5, the magnetic detection element portion 20 includes a wheatstone bridge circuit C formed by, for example, bridging four resistor portions of a first resistor portion R1, a second resistor portion R2, a third resistor portion R3, and a fourth resistor portion R4. However, the magnetic detection element portion 20 may have a circuit formed by half-bridging two resistor portions of the first resistor portion R1 and the second resistor portion R2. The first to fourth resistor portions R1 to R4 may each include one magnetoresistance element (MR element) or may include a plurality of magnetoresistance elements. The magneto-resistance effect element is, for example, an AMR element, a GMR element, a TMR element, or the like.

The wheatstone bridge circuit C in the magnetic detection element portion 20 includes, for example, a power supply port V, a ground port G, 2 output ports E1, E2, a first resistance portion R1 and a second resistance portion R2 connected in series, and a third resistance portion R3 and a fourth resistance portion R4 connected in series. One end of each of the first resistor R1 and the third resistor R3 is connected to the power supply port V. The other end of the first resistor R1 is connected to one end of the second resistor R2 and the output port E1. The other end of the third resistor R3 is connected to one end of the fourth resistor R4 and the output port E2. The other ends of the second resistor R2 and the fourth resistor R4 are connected to the ground port G. A power supply voltage of a predetermined magnitude is applied to the power supply port V, and the ground port G is grounded.

The magnetoresistance effect elements constituting the first to fourth resistor portions R1 to R4 include, for example, a lower electrode, an upper electrode, and a magnetoresistance effect film interposed between the lower electrode and the upper electrode. The magnetoresistance effect film includes, for example, a free layer, a nonmagnetic layer, a magnetization pinned layer, and an antiferromagnetic layer laminated in this order from the lower electrode side. In the case of a TMR element, the nonmagnetic layer is a tunnel barrier layer. In the case of GMR elements, the nonmagnetic layer is a nonmagnetic conductive layer.

When the first to fourth resistor portions R1 to R4 are constituted by TMR elements or GMR elements, the wheatstone bridge circuit C (fig. 5) of the magnetic detection element portion 20 changes in the magnetic field strength of the magnetic field in the X-axis direction generated from the conductor 5, the potential difference of the output ports E1 and E2 changes, and a signal corresponding to the potential difference of the output ports E1 and E2 is outputted as the sensor signal S to the signal processing portion 60. The signal corresponding to the potential difference of the output ports E1, E2 may be amplified by a differential detector and output to the a/D conversion section 61 of the signal processing section 60 as the sensor signal S.

The a/D conversion section 61 converts the sensor signal S (analog signal on the current) output from the magnetic detection section 2 into a digital signal, and the digital signal is input to the operation section 62. The arithmetic unit 62 performs arithmetic processing on the digital signal converted from the analog signal by the a/D conversion unit 61. The arithmetic unit 62 is constituted by, for example, a microcomputer, ASIC (Application Specific Integrated Circuit), or the like.

In the current sensor 1 of the present embodiment, the magnetic sensor unit 20 is not limited to the case where the magnetic sensor unit includes a magnetoresistance effect element. For example, hall elements may also be included. The hall element has a structure in which electrodes are provided on 4 sides of a semiconductor film having high carrier mobility, such as InSb, inAs, or GaAs.

[ method of manufacturing Current sensor Module ]

Further, the current sensor module may be manufactured by the following method. First, the conductor 5, the magnetic shield 4, and the magnetic detection section 2 are prepared, respectively. Next, the housing 3 is prepared. Specifically, the housing 3 is formed by molding, for example, so as to embed a part of the magnetic shield body 4 and include a pair of concave portions 31, 32. Then, the magnetic detection portion 2 is placed on the housing 3 at a position corresponding to the bottom portion 41 of the magnetic shield 4. Finally, the conductor 5 is fitted into the pair of recesses 31,32, and the conductor 5 is fixed to the housing 3 by tightening with a screw 6 or the like (see fig. 1). Thus, a current sensor module including the current sensor 1 is completed.

[ Effect of the current sensor 1 ]

According to the current sensor 1 of the present embodiment, the magnetic shield 4 has the bottom portion 41, the first wall portion 42A, and the second wall portion 42B, the bottom portion 41 being located on the opposite side of the conductor 5 from the magnetic detection portion 2 in the Y-axis direction, the first wall portion 42A and the second wall portion 42B being respectively erected on the bottom portion 41 and facing the magnetic detection portion 2 with the conductor 5 interposed therebetween in the X-axis direction. Therefore, the current sensor 1 can be mounted on the conductor 5 through which the current Im to be detected flows without changing the relative position of the magnetic detection unit 2 and the magnetic shield 4. Therefore, the current sensor 1 can ensure high measurement accuracy and can be easily attached to the conductor 5. Alternatively, the conductor 5 can be easily attached to the current sensor 1 provided in advance.

In particular, in the current sensor 1 of the present embodiment, the magnetic detection portion 2 and the magnetic shield 4 are provided in the case 3, and the magnetic detection portion 2 and the magnetic shield 4 are integrated by the case 3. Therefore, in the manufacturing stage of the current sensor 1, the relative position of the magnetic detection portion 2 and the magnetic shield body 4 is fixed, and no positional deviation occurs thereafter. Further, in the current sensor 1, the fixed conductor 5 is fitted to the pair of recesses 31,32 formed in the housing 3 in advance with a predetermined accuracy. Therefore, the relative positions of the magnetic detection unit 2 and the magnetic shield 4 can be maintained in the state of the manufacturing stage, and the error in the relative positions of the conductor 5 and the magnetic detection unit 2 and the magnetic shield 4 due to the installation work of the current sensor 1 can be made extremely small. That is, since the conductors 5 can be attached to the recesses 31,32 of the case 3 to which the magnetic detection portion 2 and the magnetic shield body 4 are fixed with a predetermined accuracy with good reproducibility and a predetermined accuracy, it is not necessary for the user to perform electric adjustment of the measurement accuracy of the relevant current sensor 1 in the stage of attaching the current sensor 1.

In the current sensor 1 of the present embodiment, if the height of the first wall portion 42A of the magnetic shield body 4, that is, the first distance H42A and the height of the second wall portion 42B, that is, the second distance H42B is 2 times or more the third distance H5 between the bottom portion 41 and the conductor 5, the measurement accuracy of the current Im can be further improved. This is because the influence of the unwanted disturbing magnetic field in the Y-axis direction on the magnetic detection unit 2 can be further reduced. Further, by setting the third distance H5 to be equal to or less than half the first distance H42A and the second distance H42B, the distance between the conductor 5 and the magnetic detection unit 2 in the Y-axis direction can be shortened. Therefore, the intensity of the magnetic flux Bm applied to the magnetic detection unit 2 can be increased, the detection sensitivity of the current Im of the current sensor 1 can be improved, and the measurement error due to the relative positional deviation between the magnetic detection unit 2 and the conductor 5 can be reduced.

In the current sensor 1 of the present embodiment, if the fourth distance H2 between the bottom 41 and the magnetic detection portion 2 is less than half the third distance H5 between the bottom 41 and the conductor 5, the shielding effect of the magnetic shield 4 on the interfering magnetic field of the magnetic detection portion 2 can be further improved.

<2 > modification of the first embodiment

[2.1 modification 1]

Fig. 6 is a schematic cross-sectional view of a current sensor 1A as a first modification (modification 1) of the first embodiment. As shown in fig. 6, the current sensor 1A further includes a yoke 7 between the conductor 5 and the magnetic detection unit 2. The structure of the current sensor 1A is substantially the same as that of the current sensor 1 except that it further has a yoke 7. The yoke 7 is a soft magnet, and gathers the magnetic flux Bm so that the magnetic flux Bm passes through itself. The yoke 7 is a plate-like member having a main surface along the XZ plane and extending in the Z-axis direction, for example. However, the shape of the yoke 7 is not limited to a plate shape. In addition, in the current sensor 1A, the dimension W7 of the yoke 7 in the X-axis direction is preferably larger than the dimension W5 of the conductor 5 in the X-axis direction (W7 > W5). The yoke 7 is made of a soft magnetic material such as silicon steel, electromagnetic steel, pure iron (SUY), permalloy, or the like as a main constituent material, similarly to the magnetic shield 4. The yoke 7 is a specific example of the "second soft magnetic body" according to the present invention.

As described above, in the current sensor 1A (fig. 6) as the first modification example, since the yoke 7 is further provided, a measurement error due to a relative positional deviation between the magnetic detection unit 2 and the conductor 5 can be reduced more than in the current sensor 1 (fig. 1, etc.) without the yoke 7.

[2.2 modification 2]

Fig. 7 is a schematic cross-sectional view of a current sensor 1B as a second modification (modification 2) of the first embodiment. As shown in fig. 7, the current sensor 1B has 2 separate magnetic shields 4a,4B as a first soft magnetic body. The structure of the current sensor 1B is substantially the same as that of the current sensor 1 except that the current sensor 1 has magnetic shields 4a,4B instead of the magnetic shield 4. The magnetic shield 4A and the magnetic shield 4B are spaced apart from each other in the X-axis direction. The magnetic detection portion 2 is located at a position corresponding to the gap 41S between the magnetic shield body 4A and the magnetic shield body 4B in the Y-axis direction. The gap 41S extends in the Z-axis direction. That is, the magnetic shield 4A and the magnetic shield 4B are not in physical contact and are disposed apart from each other. The magnetic shield 4A is a specific example corresponding to the "first portion" of the present invention, and the magnetic shield 4B is a specific example corresponding to the "second portion" of the present invention.

As described above, the current sensor 1B (fig. 7) according to the second modification includes the magnetic shield 4A and the magnetic shield 4B facing each other with the gap 41S therebetween, instead of the magnetic shield 4. Therefore, as shown in fig. 7, the magnetic flux Bm leaks from the facing portion of the magnetic shield body 4A and the magnetic shield body 4B, and the magnetic flux density of the magnetic flux Bm detected by the magnetic detection unit 2 increases. Therefore, the detection sensitivity of the current Im of the magnetic detection unit 2 can be further improved as compared with the current sensor 1 (fig. 1, etc.). Further, since the magnetic flux density of the magnetic flux Bm applied to the magnetic detection section 2 is increased, a hall element or the like having a sensitivity lower than that of a general MR element can be used as the magnetic detection element section 20 of the magnetic detection section 2 instead of the MR element, and the degree of freedom of design is increased. In the current sensor 1B, a part of the magnetic shield 4A and a part of the magnetic shield 4B may be connected. However, in such a case, the effect of increasing the density of the magnetic flux Bm detected by the magnetic detection unit 2 is limited.

[2.3 modification 3]

Fig. 8 is a schematic cross-sectional view of a current sensor 1C as a third modification (modification 3) of the first embodiment. As shown in fig. 8, the current sensor 1C has a structure in which the current sensor 1A of fig. 6 is combined with the current sensor 1B of fig. 7. That is, there is further provided a yoke 7, and as the first soft magnetic body, there are provided 2 separate magnetic shields 4a,4b in place of the magnetic shield 4.

As described above, in the current sensor 1C (fig. 8) as the third modification, a measurement error due to a relative positional deviation between the magnetic detection unit 2 and the conductor 5 can be reduced more than in the current sensor 1 (fig. 1 and the like). Further, the detection sensitivity of the current Im of the magnetic detection unit 2 can be further improved. Further, since the magnetic flux density of the magnetic flux Bm applied to the magnetic detection section 2 is increased, a hall element or the like having a sensitivity lower than that of a general MR element can be used as the magnetic detection element section 20 of the magnetic detection section 2 instead of the MR element, and the degree of freedom of design is increased. In addition, in the current sensor 1C (fig. 8), the effect of reducing the influence of magnetic noise (disturbing magnetic field) in the Y-axis direction on the magnetic detection unit 2 was also confirmed. In the current sensor 1C, a part of the magnetic shield 4A and a part of the magnetic shield 4B may be connected. However, in such a case, the effect of increasing the density of the magnetic flux Bm detected by the magnetic detection unit 2 is limited.

[2.4 modification 4]

Fig. 9 is a schematic cross-sectional view of a current sensor 1D as a fourth modification (modification 4) of the first embodiment. As shown in fig. 9, the current sensor 1D has a first upper end 43A on the opposite side of the bottom 41 in the first wall portion 42A and a second upper end 43B on the opposite side of the bottom 41 in the second wall portion 42B curved inward in the direction of approaching each other. The structure of the current sensor 1D is substantially the same as that of the current sensor 1 except that the shape of the first wall portion 42A and the shape of the second wall portion 42B are different. The distance W43 between the first upper end 43A and the second upper end 43B is preferably larger than the width W5 (W43 > W5). This is because the current sensor 1D is easily mounted in the vicinity of the conductor 5. Here, the first upper end 43A is a specific example corresponding to the "first upper end" of the present invention, and the second upper end 43B is a specific example corresponding to the "second upper end" of the present invention.

As described above, in the current sensor 1D (fig. 9) as the fourth modification, the first upper end portion 43A of the first wall portion 42A and the second upper end portion 43B of the second wall portion 42B are bent inward. Therefore, compared with the current sensor 1 (fig. 1, etc.), particularly, the influence of magnetic noise (disturbing magnetic field) in the X-axis direction on the magnetic detection unit 2 can be reduced, and the measurement accuracy can be further improved.

[2.5 modification 5]

Fig. 10 is a schematic cross-sectional view of a current sensor 1E as a fifth modification (modification 5) of the first embodiment. The current sensor 1E corresponds to the structure of the current sensor 1D of fig. 9 in which a yoke 7 is further added, and as the first soft magnetic body, 2 separate magnetic shields 4a,4b are used instead of the magnetic shield 4. Therefore, compared to the current sensor 1 (fig. 1, etc.), the influence of magnetic noise (disturbing magnetic field) in both the X-axis direction and the Y-axis direction on the magnetic detection unit 2 can be reduced, and the measurement accuracy can be further improved. Further, since the gap 41S is provided, the detection sensitivity of the current Im of the magnetic detection unit 2 can be further improved.

<3 > second embodiment

Fig. 11 is a block diagram showing a configuration example of an electrical control device including the current sensor 1 and the like. The current sensors 1,1a to 1E according to the first embodiment and the several modifications can be all mounted in the electric control device 110 shown in fig. 11, for example.

The electrical control device 110 includes, for example, a current sensor 111, a power supply device 112, and a control circuit 113. The current sensor 111 measures a current Iout output from the power supply device 112 or a current Iin input to the power supply device 112. In fig. 11, 2 current sensors 111 are arranged, but only one current sensor 111 may be arranged. Information about the current value measured by the current sensor 111 is sent to the control circuit 113. The control circuit 113 is, for example, a device that controls the operation of the current sensor 111 and the operation of the power supply device 112. The control circuit 113 adjusts the output current from the power supply device 112 based on, for example, information from the current sensor 111. The current sensors 1,1a to 1E described in the above embodiments and the like can be applied to the current sensor 111. The electrical control device according to the present invention includes: such as battery management systems, inverters, and converters for hybrid Electric vehicles (HEV: hybrid Electric Vehicle) and Electric vehicles (EV: electric Vehicle).

<4. Examples >

Next, the performance of the current sensor 1 according to the first embodiment shown in fig. 1 and the like is compared with the performance of the current sensors 1A to 1c and 1e of modification examples 1 to 3 and 5 shown in fig. 6,7,8,10, respectively.

Example 1-1

The current sensor 1 according to the first embodiment was obtained by simulation: the intensity of the magnetic flux Bm applied to the center position of the magnetic detection unit 2 when the current Im of 600A flows through the conductor 5, the influence of magnetic noise in the Y-axis direction, the influence of magnetic noise in the X-axis direction, and the positional deviation tolerance. The dimensions of the respective portions of the conductor 5 and the magnetic shield 4 are shown in fig. 12. The center position of the magnetic detection section 2 as a detection point was set at a height of 1.5mm from the surface of the bottom 41. The effect of magnetic noise in the Y-axis direction is an output error when an external magnetic field of 1mT is present in the Y-axis direction. The effect of magnetic noise in the X-axis direction is an output error in the case of an external magnetic field of 1mT in the X-axis direction. Positional deviation tolerance refers to: the magnetic detection unit 2 is offset from the reference position by a maximum output error of 0.3mm in each of the X-axis direction, the Y-axis direction, and the Z-axis direction.

Examples 1 to 2

The performance of the current sensor 1A according to modification 1 of the first embodiment was obtained in the same manner as in example 1-1. However, the yoke 7 is made of the same material as the magnetic shield 4, and the dimension of the yoke 7 in the X-axis direction is 12mm and the dimension of the yoke 7 in the Y-axis direction is 1.5mm. In addition, the yoke 7 is located at an intermediate position of the bottom 41 and the magnetic shield 4.

Examples 1 to 3

The performance of the current sensor 1B according to modification 2 of the first embodiment was obtained in the same manner as in example 1-1. However, the width of the gap 41S is 2mm.

Examples 1 to 4

The performance of the current sensor 1C according to modification 3 of the first embodiment was obtained in the same manner as in example 1-1. However, the yoke 7 is made of the same material as the magnetic shield 4, and the dimension of the yoke 7 in the X-axis direction is 12mm and the dimension of the yoke 7 in the Y-axis direction is 1.5mm. In addition, the yoke 7 is located at an intermediate position of the bottom 41 and the magnetic shield 4. The width of the gap 41S is 2mm.

Examples 1 to 5

The performance of the current sensor 1E according to modification 5 of the first embodiment was obtained in the same manner as in example 1-1. However, the yoke 7 is made of the same material as the magnetic shield 4, and the dimension of the yoke 7 in the X-axis direction is 12mm and the dimension of the yoke 7 in the Y-axis direction is 1.5mm. In addition, the yoke 7 is located at an intermediate position of the bottom 41 and the magnetic shield 4. The width of the gap 41S is 2mm. The distance W43 between the first upper end 43A of the first wall portion 42A and the second upper end 43B of the second wall portion 42B is 14mm.

The performance of each of the current sensors of examples 1-1 to 1-5 is summarized in FIG. 13. However, in FIG. 13, characteristic values of the respective parameters of example 1-1 are normalized as 1, and the respective performances of examples 1-2 to 1-5 are represented. Further, the higher the value of the magnetic flux Bm, the better. Regarding the magnetic noise in the X-axis direction and the magnetic noise in the Y-axis direction, the lower the numerical value, the smaller the error, and therefore the better the numerical value. Regarding positional deviation tolerance, the lower the numerical value is, the better.

As shown in fig. 13, in example 1-2, the magnetic flux Bm, the magnetic noise in the X-axis direction, and the magnetic noise in the Y-axis direction were lower in their respective performances than in example 1-1, but the positional deviation tolerance was improved. That is, it was confirmed that positional deviation tolerance can be improved by providing the yoke.

As shown in fig. 13, it is clear that in example 1-3, the magnetic noise in the X-axis direction and the positional deviation resistance are improved, respectively, in comparison with example 1-1, although the magnetic noise in the Y-axis direction is more susceptible to the influence. Further, it was confirmed that the intensity of the magnetic flux Bm applied to the magnetic detection unit 2 was significantly increased. That is, it was confirmed that by using the magnetic shield provided with the gap, the performance other than the magnetic noise in the X-axis direction can be improved.

As shown in fig. 13, it is understood that in examples 1 to 4, the strength of the magnetic flux Bm is reduced as compared with examples 1 to 3, but the positional deviation tolerance performance is further improved.

As shown in fig. 13, it is clear that in examples 1 to 5, the strength of the magnetic flux Bm, the magnetic noise in the X-axis direction, and the positional deviation tolerance can be improved as compared with examples 1 to 4.

Examples 2-1 to 2-3

Next, with the current sensor 1 of the first embodiment, the following is obtained by simulation: the effect on the respective performances in the case of changing the position of the conductor 5 in the Y-axis direction. The structure of example 2-1 is the same as that of example 1-1 except that the bottom 41 is spaced 3.0mm from the conductor 5. The structure of example 2-2 is the same as that of example 1-1 except that the bottom 41 is spaced 9.0mm from the conductor 5. The structure of example 2-3 is the same as that of example 1-1 except that the interval between the bottom 41 and the center position of the magnetic detection section 2 as the detection point is 4.5 mm.

The performance of each of the current sensors of examples 2-1 to 2-3 is summarized in combination with the results of example 1-1 as shown in FIG. 14. However, in FIG. 14, characteristic values of the respective parameters of example 1-1 are normalized as 1, and the respective performances of examples 2-1 to 2-3 are represented.

As shown in fig. 14, in example 2-1 in which the conductor 5 is located near the bottom 41, the intensity of the magnetic flux Bm applied to the magnetic detection unit 2 is improved, and the performance of each of the magnetic noise in the X-axis direction and the magnetic noise in the Y-axis direction is also improved, as compared with example 1-1. However, it was found that example 1-1 was better than example 2-1 in terms of positional deviation tolerance.

On the other hand, in example 2-2 in which the conductor 5 was located away from the bottom 41, it was found that the strength of the magnetic flux Bm applied to the magnetic detection unit 2, the magnetic noise in the X-axis direction, and the magnetic noise in the Y-axis direction were all degraded as compared with example 1-1. However, it was found that example 2-2 was better than example 1-1 in terms of positional deviation tolerance.

In example 2-3 in which the magnetic detection unit 2 is located away from the bottom 41 (i.e., close to the conductor 5), the strength of the magnetic flux Bm is improved, and the performance of each of the magnetic noise in the X-axis direction and the magnetic noise in the Y-axis direction is also improved, as compared with example 1-1. However, it was found that examples 2-3 were lower in terms of positional deviation tolerance than examples 1-1, 2-1.

Examples 3-1 to 3-2

Next, the current sensor 1E according to modification 5 of the first embodiment was obtained by simulation: the influence on the respective performances with changing the width of the yoke 7. The structure of embodiment 3-1 is the same as that of embodiment 1-5 except that the width of the yoke 7 is narrower than the width of the conductor 5. The structure of embodiment 3-2 is the same as that of embodiment 1-5 except that the width of the yoke 7 is wider than the width of the conductor 5.

The performance of each of the current sensors of examples 3-1 to 3-2 is summarized in combination with the results of examples 1 to 5 as shown in fig. 15. However, in FIG. 15, the characteristic values of the respective parameters of examples 1-5 were normalized as 1, and the respective performances of examples 3-1 to 3-2 were represented.

As shown in fig. 15, in example 3-1 in which the width of the yoke 7 is made narrower than the width of the conductor 5, the strength of the magnetic flux Bm is slightly improved as compared with example 1-5, but the positional deviation tolerance is reduced. On the other hand, in example 3-2 in which the width of the yoke 7 is made wider than the width of the conductor 5, it is found that the strength of the magnetic flux Bm is slightly lower than that of example 1-5, but the positional deviation tolerance is improved.

Examples 4-1 to 4-2

Next, the current sensor 1C according to modification 3 of the first embodiment was obtained by simulation: the first wall portion 42A of the magnetic shield 4A and the second wall portion 42B of the magnetic shield 4B are each inclined, and thus affect the respective performances. The structure of embodiment 4-1 is the same as that of embodiment 1-4 except that the first wall portion 42A of the magnetic shield body 4A and the second wall portion 42B of the magnetic shield body 4B are each inclined inward. The structure of embodiment 4-2 is the same as that of embodiment 1-4 except that the first wall portion 42A of the magnetic shield body 4A and the second wall portion 42B of the magnetic shield body 4B are each inclined to the outside.

The performance of each of the current sensors of examples 4-1 to 4-2 is summarized in combination with the results of examples 1-4,1-5 as shown in FIG. 16. However, in FIG. 16, the characteristic values of the respective parameters of example 1-1 are normalized as 1, and the respective performances of example 4-1,4-2,1-4,1-5 are represented.

As shown in fig. 16, in example 4-1, the strength of the magnetic flux Bm was slightly increased and the influence of magnetic noise in the X-axis direction was improved, but the positional deviation tolerance performance was decreased, as compared with example 1-4. On the other hand, it was found that in example 4-2, the magnetic noise and the positional deviation resistance in the X-axis direction were all reduced as compared with example 1-4.

The embodiments and modifications described above are described for the convenience of understanding the present invention, and do not limit the present invention. Accordingly, each element disclosed in the above embodiments and the like also includes all design changes and equivalents which fall within the technical scope of the present invention. That is, the present invention is not limited to the above embodiment and the like, and various changes may be made.

For example, in the current sensor 1 (fig. 1 to 3) of the above embodiment, the structure in which the first wall portion 42A and the second wall portion 42B are each in physical contact with the bottom portion 41 in the magnetic shield body 4 is exemplified, but the present invention is not limited to this. For example, the bottom 41 may be physically separated from at least one of the first wall portion 42A and the second wall portion 42B. That is, the bottom portion of the present invention and the first wall portion and the second wall portion need only be magnetically connected to each other even without physical contact.

In addition, in the current sensor 1 (fig. 1 to 3) of the above-described embodiment, each coupling portion of the bottom portion 41 in the magnetic shield body 4 and the first wall portion 42A and the second wall portion 42B has a curved shape. However, the present invention is not limited to this aspect. For example, the coupling parts may have a bent shape or may have a chamfered shape with a chamfer.

The present invention is not limited to the configuration in which the current sensor is attached to the conductor through which the current to be detected flows, but includes a concept in which the conductor through which the current to be detected flows is attached to the current sensor.

The present invention can also adopt the following configuration.

(1)

A current sensor is provided with:

a magnetic detection unit to which a magnetic flux in a second direction is applied, the magnetic flux in the second direction being generated by a current flowing through the conductor in the first direction; and

a first soft magnetic body having a bottom portion, a first wall portion, and a second wall portion, the bottom portion being located on a side opposite to the conductor as viewed from the magnetic detection portion in a third direction orthogonal to the first direction, the first wall portion and the second wall portion being respectively erected on the bottom portion and facing the magnetic detection portion with the conductor therebetween in the second direction.

(2)

The current sensor according to the item (1), wherein,

further has a second soft-magnetic body which is arranged on the first soft-magnetic body,

the second soft magnetic body is disposed between the conductor and the magnetic detection portion.

(3)

The current sensor according to the item (2), wherein,

the second direction of the second soft magnetic body has a larger dimension than the second direction of the conductor.

(4)

The current sensor according to any one of the above (1) to (3), wherein,

the first soft magnetic body includes a first portion and a second portion that are spaced apart and opposed in the second direction.

(5)

The current sensor according to the item (4), wherein,

the magnetic detection portion is located at a position overlapping with a gap between the first portion and the second portion in the third direction.

(6)

The current sensor according to any one of the above (1) to (5), wherein,

a first upper end portion of the first wall portion on an opposite side of the bottom portion and a second upper end portion of the second wall portion on an opposite side of the bottom portion are curved in a direction approaching each other.

(7)

The current sensor according to any one of (1) to (6), wherein,

the first distance from the bottom to the first top of the first wall portion and the second distance from the bottom to the second top of the second wall portion are each more than 2 times the third distance of the bottom from the conductor.

(8)

The current sensor according to the item (7), wherein,

the fourth distance of the bottom portion from the magnetic detection portion is less than half of the third distance of the bottom portion from the conductor.

(9)

The current sensor according to any one of (1) to (8), wherein,

Further comprises a shell body, wherein the shell body is provided with a plurality of grooves,

the housing includes a pair of recesses aligned in the first direction,

the pair of recesses are configured to be capable of being fitted to the conductors.

(10)

The current sensor according to the item (9), wherein,

the conductor is electrically insulated from the magnetic detection portion and the first soft magnet by the housing.

(11)

An electrical control device provided with the current sensor according to any one of (1) to (10).

(12)

A current sensor module is provided with:

a conductor;

(13)

A method for manufacturing a current sensor module includes a conductor, a magnetic detection unit, a first soft magnetic body, and a case,

The magnetic detection portion is applied with a magnetic flux in a second direction generated by a current flowing through the conductor in the first direction,

and comprises:

preparing the first soft magnetic body having a bottom portion, a first wall portion and a second wall portion, the bottom portion being expanded in the first direction and the second direction, the first wall portion and the second wall portion being respectively erected on the bottom portion and facing the magnetic detection portion with the conductor therebetween in the second direction;

preparing the housing including a pair of recesses arranged in the first direction and provided with the first soft magnet and the magnetic detection portion; and

the conductors are fitted in the pair of recesses.

The present disclosure contains the subject matter related to the disclosure in japanese priority patent application JP2022-005257 filed in the japanese patent office at 1 month 17 of 2022, the entire contents of which are incorporated herein by reference.

It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible depending on the design requirements and other factors, but they are included within the scope of the appended claims or their equivalents.

Claims

1. A current sensor is provided with:

2. The current sensor according to claim 1, wherein,

3. The current sensor according to claim 2, wherein,

4. The current sensor according to any one of claim 1 to claim 3, wherein,

5. The current sensor according to claim 4, wherein,

6. The current sensor according to any one of claim 1 to claim 5, wherein,

7. The current sensor according to any one of claim 1 to claim 6, wherein,

8. The current sensor according to claim 7, wherein,

9. The current sensor according to any one of claim 1 to claim 8, wherein,

the housing includes a pair of recesses aligned in the first direction,

10. The current sensor according to claim 9, wherein,

11. An electrical control device provided with the current sensor according to any one of claims 1 to 10.

12. A current sensor module is provided with:

a conductor;

13. A method for manufacturing a current sensor module includes a conductor, a magnetic detection unit, a first soft magnetic body, and a case,

And comprises:

the conductors are fitted in the pair of recesses.