JP2023104335A - Current sensor, electric control device, current sensor module and manufacturing method therefor - Google Patents

Abstract

To provide a current sensor which has high measurement accuracy and can be easily mounted at a mounting position.SOLUTION: The current sensor includes a magnetic detection unit and a first soft magnetic body. A magnetic flux in a second direction generated by a current flowing through a conductor in the first direction is applied to the magnetic detection unit. The first soft magnetic body has: a bottom portion located on a side opposite to the conductor as viewed from the magnetic detection unit in a third direction orthogonal to the first direction; and a pair of wall portions each erected on the bottom portion and disposed to face each other so as to sandwich the conductor and the magnetic detection unit in the second direction.SELECTED DRAWING: Figure 3

Description

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

In recent years, current sensors have been used in hybrid electric vehicles (HEVs) and electric vehicles (EVs) to measure the remaining battery level, measure the drive current of motors, and power control devices such as converters and inverters. is used. 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 busbar is known. A magnetic current sensor has, for example, an AMR (Anisotropic Magneto Resistive effect) element, a GMR (GiantMagnetoResistive effect) element, a TMR (TunnelMagnetoResistive effect) element or other magnetoresistive effect element, a Hall element, or the like, as a magnetic detection element. In the current sensor, a current flowing through a primary conductor such as a busbar is detected in a non-contact state by the magnetoresistive effect element and the magnetic detection element.

For example, Patent Literature 1 discloses a current sensor that includes a ring-shaped magnetic core having a gap and a magnetic sensor including a magnetic detection element arranged in the gap. In the current sensor of Patent Document 1, the magnetic flux generated from the conductor can be focused on the magnetic core, and the magnetic flux focused by the magnetic core can be applied to the magnetic detection element arranged in the air gap.

JP 2019-78542 A

By the way, it is desired that a current sensor having a magnetic sensor has high measurement accuracy and can be easily installed depending on the location where it should be installed.

Therefore, it is desired to provide a current sensor which has high measurement accuracy and which can be easily attached to a location where it should be attached.

A current sensor as an embodiment of the present invention includes a magnetic detection section and a first soft magnetic body. The magnetic detector is given a magnetic flux in the second direction generated by a current flowing through the conductor along the first direction. The first soft magnetic body has a bottom portion located on the side opposite to the conductor when viewed from the magnetic detection portion in a third direction perpendicular to the first direction, and a bottom portion, and the conductor and the magnetic detection portion are erected in the second direction. and a pair of wall portions arranged opposite to each other so as to sandwich the wall portion.

An electric control device and a current sensor module according to one embodiment of the present invention includes the current sensor according to one embodiment described above.

A method of manufacturing a current sensor module according to an embodiment of the present invention includes a conductor, a magnetic detection section to which a magnetic flux in a second direction generated by a current flowing through the conductor in a first direction is applied, a first soft magnetic body and a housing, the bottom extending along the first direction and the second direction, and the bottom extending upright from the bottom and sandwiching the conductor and the magnetic detection unit in the second direction. preparing a first soft magnetic body having a first wall portion and a second wall portion facing each other, and including a pair of recessed portions aligned in the first direction, the first soft magnetic body and the magnetic detection portion and fitting the conductors into the pair of recesses.

According to the current sensor as one embodiment of the present invention, it is possible to attach the magnetism detecting section and the first soft magnetic body to the conductor through which the current to be detected flows without changing the relative positions thereof. Therefore, it can be attached easily while ensuring high measurement accuracy.
Note that the effect of the present invention is not limited to this, and may be any of the effects described below.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view showing the whole structural example of the current sensor which concerns on the 1st Embodiment of this invention. 2 is a perspective view schematically showing main parts and conductors of the current sensor shown in FIG. 1; FIG. It is a schematic diagram showing the cross section of the current sensor shown in FIG. 2 is a block diagram showing a schematic configuration of a current sensor shown in FIG. 1; FIG. 2 is a circuit diagram schematically showing the circuit configuration of the magnetic detection unit shown in FIG. 1; FIG. It is a schematic diagram showing the cross section of the current sensor as the 1st modification of the 1st Embodiment of this invention. It is a schematic diagram showing the cross section of the current sensor as a 2nd modification of the 1st Embodiment of this invention. It is a schematic diagram showing the cross section of the current sensor as the 3rd modification of the 1st Embodiment of this invention. It is a schematic diagram showing the cross section of the current sensor as the 4th modification of the 1st Embodiment of this invention. It is a schematic diagram showing the cross section of the current sensor as the 5th modification of the 1st Embodiment of this invention. It is a block diagram showing an example of composition of an electric control device concerning a 2nd embodiment of the present invention. FIG. 2 is a schematic diagram showing a cross-sectional structure of a current sensor according to Example 1-1 of the present invention; FIG. 2 is an explanatory diagram for explaining Examples 1-1 to 1-5 of the present invention; FIG. 5 is an explanatory diagram for explaining Examples 2-1 to 2-3 of the present invention; FIG. 5 is an explanatory diagram for explaining Examples 3-1 and 3-2 of the present invention; FIG. 4 is an explanatory diagram for explaining Examples 4-1 and 4-2 of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description will be given in the following order.
0. Background 1. First Embodiment An example of a current sensor arranged near a conductor.
2. 2. Modified example of the first embodiment 2.1 Modified example 1
2.2 Modification 2
2.3 Modification 3
2.4 Modification 4
2.5 Modification 5
3. Second Embodiment An example of an electric control device provided with a current sensor.
4. Example

<0. History>
The measurement accuracy of a so-called magnetic current sensor is affected by variations in shape and errors in the relative positions of the primary conductor (busbar) through which the current to be detected flows, the magnetic detection element, the magnetic yoke and the magnetic shield. The measurement accuracy of a magnetic current sensor is also affected by the sensitivity of the magnetic detection element and the magnetic characteristics of the magnetic yoke. Therefore, in order for the current sensor to achieve high measurement accuracy, factors that affect measurement accuracy, such as the offset of multiple magnetic detection elements and variations in sensitivity, must be adjusted during the current sensor manufacturing process and current sensor installation process. There is a need to. Currently, the mainstream method for adjusting such factors affecting measurement accuracy is to electrically perform, for example, an integrated circuit integrated with the magnetic sensing element.

By the way, it is desirable to fix the relative positions of the primary conductor, the magnetic detection element, and the magnetic shield (or the magnetic yoke) as a preliminary step for such electrical adjustment. However, in conventional magnetic current sensors, the primary conductor is inserted between the magnetic detection element and the magnetic shield (or magnetic yoke). For this reason, it is necessary to insert the primary conductor through the opening of the current sensor in which the magnetic detection element and the magnetic shield (or magnetic yoke) are integrated. . Alternatively, in the case where the primary conductor cannot be moved or the primary conductor cannot be partially removed, the magnetic detection element and the magnetic shield (or magnetic After installing the yoke separately, it is necessary for the user to make electrical adjustments to the factors affecting the measurement accuracy mentioned above. As described above, with conventional current sensors, the procedure for installing them in the vicinity of the primary conductor is limited, and the user is required to make electrical adjustments related to the measurement accuracy of the current sensor. , it may be difficult to ensure high measurement accuracy.

Therefore, the applicant of the present invention has made repeated studies and improvements in view of the above problems to provide a current sensor that has high measurement accuracy and can be easily attached to a location where it should be attached, and an electric control device having the same. Arrived.

<1. First Embodiment>
[Configuration of current sensor 1]
First, the configuration of a current sensor 1 as a first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. FIG. 1 is a perspective view showing an example of the overall configuration of a current sensor 1. FIG. As shown in FIG. 1 , the current sensor 1 includes, for example, a magnetic detection section 2 and a magnetic shield 4 . The current sensor 1 is arranged near the conductor 5, for example. The conductor 5 extends, for example, in the Z-axis direction. A current Im to be detected by the current sensor 1 flows through the conductor 5 along the Z-axis direction. A module including the current sensor 1 and the conductor 5 corresponds to the current sensor module of the present invention.

Current sensor 1 may further include housing 3 . The housing 3 is made of an insulating material such as resin, and includes a pair of recesses 31 and 32 aligned in the Z-axis direction along which the conductor 5 extends. The pair of recesses 31 and 32 are configured to be fittable with the conductor 5 . The conductor 5 is provided with holes at positions corresponding to the pair of recesses 31 and 32, for example, and the conductor 5 is screwed into the pair of recesses 31 and 32 by screws 6, for example. Also, the magnetic detection unit 2 and the magnetic shield 4 are provided in the housing 3 . A part of the magnetic shield 4 is embedded in the housing 3 . Therefore, by fixing the conductor 5 to the housing 3 , the relative positions of the conductor 5 and the magnetic detection section 2 and the magnetic shield 4 are fixed. Further, the conductor 5 is electrically insulated from the magnetic detection section 2 and the magnetic shield 4 by the housing 3 . A high voltage of, for example, several hundred volts or more is applied to the conductor 5, while the magnetic detection unit 2 is a device driven by a low voltage of, for example, several volts. However, the voltages applied to the conductor 5 and the magnetic detection unit 2 are not limited to the above, and can be selected arbitrarily.
In addition, in FIG. 1, the conductor 5 is indicated by a broken line in order to clearly show the housing 3 and the magnetic detection section 2. As shown in FIG. Moreover, in the present embodiment, the conductor 5 is not included in the constituent elements of the current sensor 1 as an example.

FIG. 2 is a perspective view schematically showing the main part of the current sensor 1 and the conductor 5. As shown in FIG. Specifically, FIG. 2 shows the positional relationship between the conductor 5 , the magnetic detection section 2 of the current sensor 1 and the magnetic shield 4 , and the appearance of the magnetic shield 4 . Moreover, FIG. 3 is a schematic diagram showing a cross section of the current sensor 1 in the XY plane orthogonal to the Z-axis direction. In both FIGS. 2 and 3, illustration of the housing 3 is omitted.

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

(Conductor 5)
The conductor 5 is made of a highly conductive non-magnetic material such as Cu (copper). The conductor 5 is, for example, a substantially plate-like body extending in the Z-axis direction as the longitudinal direction and having the Y-axis direction as the thickness direction. The conductor 5 is arranged so as to pass through the space surrounded by the magnetic shield 4 which is roughly U-shaped.

(Magnetic shield 4)
The magnetic shield 4 is a member that magnetically protects the magnetic detector 2 from disturbance magnetic fields. In other words, the magnetic shield 4 is a soft magnetic material that mitigates the influence of an unnecessary external magnetic field (magnetic flux) other than the magnetic flux Bm to be detected on the magnetic detection section 2 . The magnetic shield 4 acts to prevent the magnetic flux Bm induced by the current Im flowing through the conductor 5 from being disturbed by the disturbance magnetic field. As shown in FIG. 3, the magnetic shield 4 has a substantially U shape as a whole in the XY cross section. The magnetic shield 4 is spaced apart without physical contact with the conductor 5 . Furthermore, the magnetic shield 4 is electrically insulated from the conductor 5 .

The magnetic shield 4 includes a bottom portion 41, a first wall portion 42A and a second wall portion 42B. The bottom portion 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 plate-like portions extending along the YZ plane, for example. The first wall portion 42A and the second wall portion 42B stand on the bottom portion 41, respectively, and are opposed to each other so as to sandwich the conductor 5 and the magnetic detection portion 2 in the X-axis direction. The magnetic shield 4 includes, for example, silicon steel, electromagnetic steel, pure iron (SUY), permalloy, ferrite, or other soft magnetic material as a main constituent material.
The magnetic shield 4 is a specific example corresponding to the "first soft magnetic body" of the present invention. The bottom portion 41 is a specific example corresponding to the "bottom portion" 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 detector 2)
The magnetic detection part 2 is provided between the conductor 5 and the bottom part 41 of the magnetic shield 4 in the Y-axis direction. That is, the magnetic detection unit 2 is provided at a position overlapping both the conductor 5 and the bottom portion 41 of the magnetic shield 4 in the Y-axis direction. Therefore, the bottom portion 41 is located on the side opposite to the conductor 5 when viewed from the magnetic detection portion 2 in the Y-axis direction. In this embodiment, the center position of the magnetic detection unit 2 in the X-axis direction is aligned with the center position of the conductor 5 in the X-axis direction, and the center position of the magnetic shield 4 in the X-axis direction. is desirable. However, the present invention is not limited to this. In addition, although the magnetic detection section 2 is shown separated from the magnetic shield 4 in FIG. 3, the magnetic detection section 2 and the magnetic shield 4 may be in contact with each other. However, the magnetic detection part 2 and the conductor 5 are separated from each other without physical contact and are electrically insulated from each other. A magnetic flux Bm induced around the conductor 5 is applied to the magnetic detector 2 when the current Im flows through the conductor 5 . The magnetic detector 2 detects the magnitude and direction of the magnetic flux Bm. A detailed configuration of the magnetic detection unit 2 will be described later.

In the current sensor 1, as shown in FIG. 3, a first distance H42A from the bottom portion 41 to the first top portion 42AT of the first wall portion 42A and a second distance H42A from the bottom portion 41 to the second top portion 42BT of the second wall portion 42B. The distance H42B is preferably twice or more the third distance H5 between the bottom 41 and the conductor 5, respectively. That is, the center position of the conductor 5 is preferably at a position that is not more than half the height of the first wall portion 42A and not more than half the height of the second wall portion 42B with the upper surface of the bottom portion 41 as a reference. This is because the influence of an unnecessary disturbance magnetic field (especially a disturbance magnetic field in the Y-axis direction) on the magnetic detection section 2 can be further reduced. Note that FIG. 3 illustrates a case where the first distance H42A, which is the height of the first wall portion 42A, and the second distance H42B, which is the height of the second wall portion 42B, are equal. It is not limited to this. The first distance H42A and the second distance H42B may be different from each other.

Furthermore, in the current sensor 1, as shown in FIG. 3, the fourth distance H2 between the bottom portion 41 and the magnetic detection portion 2 is preferably less than half the third distance H5 between the bottom portion 41 and the conductor 5. This is because the effect of shielding the magnetic detection unit 2 from the disturbance magnetic field can be further enhanced.

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

FIG. 5 is a circuit diagram schematically showing the circuit configuration of the magnetic detection element section 20 shown in FIG. As shown in FIG. 5, the magnetic sensing element section 20 is formed by connecting four resistance sections, for example, a first resistance section R1, a second resistance section R2, a third resistance section R3, and a fourth resistance section R4. It has a Wheatstone bridge circuit C of However, the magnetic detection element section 20 may have a circuit formed by half-bridge connecting two resistance sections, the first resistance section R1 and the second resistance section R2. Each of the first to fourth resistance units R1 to R4 may include one magnetoresistive element (MR element), or may include a plurality of magnetoresistive elements. The magnetoresistive element is, for example, an AMR element, a GMR element, or a TMR element.

The Wheatstone bridge circuit C included in the magnetic detection element unit 20 includes, for example, a power supply port V, a ground port G, two output ports E1 and E2, and a first resistor R1 and a second resistor R2 connected in series. , a third resistance portion R3 and a fourth resistance portion R4 connected in series. One end of each of the first resistor portion R1 and the third resistor portion R3 is connected to the power port V. As shown in FIG. The other end of the first resistance portion R1 is connected to one end of the second resistance portion 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. Each other end of the second resistance portion R2 and the fourth resistance portion R4 is 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 connected to the ground.

The magnetoresistive elements forming the first to fourth resistance sections R1 to R4 have, for example, a lower electrode, an upper electrode, and a magnetoresistive film sandwiched between the lower and upper electrodes. The magnetoresistive film includes, for example, a free layer, a nonmagnetic layer, a fixed magnetization layer and an antiferromagnetic layer, which are stacked in order from the lower electrode side. In the case of TMR elements, the non-magnetic layer is a tunnel barrier layer. For GMR elements, the non-magnetic layer is a non-magnetic conductive layer.

When the first to fourth resistance units R1 to R4 are composed of TMR elements or GMR elements, the magnetic field strength of the magnetic field in the X direction generated from the conductor 5 in the Wheatstone bridge circuit C (FIG. 5) of the magnetic detection element unit 20 , the potential difference between the output ports E1 and E2 changes, and a signal corresponding to the potential difference between the output ports E1 and E2 is output as the sensor signal S to the signal processing unit 60 . A signal corresponding to the potential difference between the output ports E1 and E2 may be amplified by a difference detector and output as the sensor signal S to the A/D converter 61 of the signal processor 60 .

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

Note that the current sensor 1 of the present embodiment is not limited to the case where the magnetic detection element section 20 includes a magnetoresistive effect element. For example, it may include a Hall element.
The Hall element has a structure in which electrodes are provided on four sides of a semiconductor film such as InSb, InAs, or GaAs with high carrier mobility.

[Manufacturing method of current sensor module]
Note that the current sensor module can be manufactured as follows. First, the conductor 5, the magnetic shield 4, and the magnetic detection part 2 are each prepared. Next, the housing 3 is prepared. Specifically, for example, by molding, the housing 3 is formed so as to embed a portion of the magnetic shield 4 and to include a pair of concave portions 31 and 32 . After that, the magnetic detector 2 is placed in the housing 3 at a position corresponding to the bottom 41 of the magnetic shield 4 . Finally, the conductor 5 is fitted into the pair of recesses 31 and 32, and the conductor 5 is fixed to the housing 3 by fastening with screws 6 (see FIG. 1). As described above, a current sensor module including the current sensor 1 is completed.

[Action and effect of current sensor 1]
According to the current sensor 1 of the present embodiment, the magnetic shield 4 is erected on the bottom portion 41 located on the opposite side of the conductor 5 when viewed from the magnetic detection portion 2 in the Y-axis direction, and on the bottom portion 41, and on the X-axis direction. It has a first wall portion 42A and a second wall portion 42B facing each other so as to sandwich the conductor 5 and the magnetic detection portion 2 in the direction. Therefore, the current sensor 1 can be attached to the conductor 5 through which the current Im to be detected flows without changing the relative positions of the magnetic detection section 2 and the magnetic shield 4 . Therefore, the current sensor 1 can be easily attached to the conductor 5 while ensuring high measurement accuracy. Alternatively, the conductor 5 can be easily attached to the current sensor 1 that is installed in advance.

In particular, in the current sensor 1 of the present embodiment, the magnetic detection unit 2 and the magnetic shield 4 are provided in the housing 3, and the magnetic detection unit 2 and the magnetic shield 4 are integrated through the housing 3. Therefore, the relative positions of the magnetic detector 2 and the magnetic shield 4 are fixed at the manufacturing stage of the current sensor 1, and no positional deviation occurs thereafter. Furthermore, in the current sensor 1 , the conductor 5 is fitted into a pair of concave portions 31 and 32 previously formed in the housing 3 with a predetermined accuracy and fixed. Therefore, the relative position of the magnetic detection unit 2 and the magnetic shield 4 is maintained in the state of the manufacturing stage, and the error in the relative position of the conductor 5 with respect to the magnetic detection unit 2 and the magnetic shield 4 due to the installation work of the current sensor 1 is reduced. can also be very small. That is, since the conductor 5 can be attached with good reproducibility and a predetermined accuracy to the concave portions 31 and 32 of the housing 3 to which the magnetic detection unit 2 and the magnetic shield 4 are fixed with a predetermined accuracy, the mounting stage of the current sensor 1 , the user does not have to perform electrical adjustment related to the measurement accuracy of the current sensor 1 .

In addition, in the current sensor 1 of the present embodiment, the first distance H42A, which is the height of the first wall portion 42A of the magnetic shield 4, and the second distance H42B, which is the height of the second wall portion 42B, are separated from the bottom portion 41 and the conductor. 5, the measurement accuracy of the current Im is further improved. This is because, in particular, the influence of the unwanted disturbance 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 half or less of the first distance H42A and the second distance H42B, the distance in the Y-axis direction between the conductor 5 and the magnetic detection section 2 can be reduced. Therefore, the strength of the magnetic flux Bm applied to the magnetic detection unit 2 can be increased, the detection sensitivity of the current Im in the current sensor 1 is improved, and the relative positional deviation between the magnetic detection unit 2 and the conductor 5 Measurement errors can be reduced.

Further, in the current sensor 1 of the present embodiment, if the fourth distance H2 between the bottom portion 41 and the magnetic detection portion 2 is less than half the third distance H5 between the bottom portion 41 and the conductor 5, the magnetic detection by the magnetic shield 4 The effect of shielding the portion 2 from the disturbance magnetic field can be further enhanced.

<2. Modification of First Embodiment>
[2.1 Modification 1]
FIG. 6 is a schematic cross-sectional view showing a current sensor 1A as a first modification (modification 1) of the first embodiment. The current sensor 1A further has a magnetic yoke 7 provided between the conductor 5 and the magnetic detection section 2, as shown in FIG. The configuration of the current sensor 1A is substantially the same as the configuration of the current sensor 1, except that the magnetic yoke 7 is further provided. The magnetic yoke 7 is a soft magnetic body that converges the magnetic flux Bm so that the magnetic flux Bm passes through itself. The magnetic yoke 7 is, for example, a plate-shaped member having a main surface along the XZ plane and extending in the Z-axis direction. However, the shape of the magnetic yoke 7 is not limited to a plate shape. In the current sensor 1A, the dimension W7 of the magnetic 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 magnetic yoke 7, like the magnetic shield 4, contains a soft magnetic material such as silicon steel, electromagnetic steel, pure iron (SUY), permalloy, etc. as a main constituent material. The magnetic yoke 7 is a specific example corresponding to the "second soft magnetic body" of the present invention.

As described above, the current sensor 1A (FIG. 6) as the first modified example is further provided with the magnetic yoke 7. Therefore, compared with the current sensor 1 (FIG. 1, etc.) not provided with the magnetic yoke 7, Measurement errors caused by relative positional deviation between the magnetic detection unit 2 and the conductor 5 can be further reduced.

[2.2 Modification 2]
FIG. 7 is a schematic cross-sectional view showing a current sensor 1B as a second modified example (modified example 2) of the first embodiment. As shown in FIG. 7, the current sensor 1B has magnetic shields 4A and 4B divided into two as the first soft magnetic body. The configuration of the current sensor 1B is substantially the same as the configuration of the current sensor 1, except that the magnetic shield 4 is replaced with magnetic shields 4A and 4B. The magnetic shield 4A and the magnetic shield 4B are arranged so as to face each other with a gap in the X-axis direction. The magnetic detection unit 2 is located at a position corresponding to the gap 41S between the magnetic shields 4A and 4B in the Y-axis direction. Note that the gap 41S extends in the Z-axis direction. That is, the magnetic shield 4A and the magnetic shield 4B are arranged apart from each other without physically contacting each other.
The magnetic shield 4A is a specific example corresponding to the "first part" of the invention, and the magnetic shield 4B is a specific example corresponding to the "second part" of the invention.

Thus, in the current sensor 1B (FIG. 7) as the second modified example, instead of the magnetic shield 4, the magnetic shield 4A and the magnetic shield 4B are arranged so as to face each other across the gap 41S. . Therefore, as shown in FIG. 7, the magnetic flux Bm leaks from the facing portion of the magnetic shield 4A and the magnetic shield 4B, and the magnetic flux density of the magnetic flux Bm detected by the magnetic detection section 2 increases. Therefore, compared with the current sensor 1 (FIG. 1 etc.), the detection sensitivity of the current Im in the magnetic detection part 2 can be improved more. Further, since the magnetic flux density of the magnetic flux Bm imparted to the magnetic detection section 2 is improved, instead of the MR element as the magnetic detection element section 20 of the magnetic detection section 2, a Hall element or the like, which generally has lower sensitivity than the MR element, can be used. It can also be used, and the degree of freedom in design is improved. In addition, 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 that 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 showing 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 configuration in which the current sensor 1A of FIG. 6 and the current sensor 1B of FIG. 7 are combined. That is, it further includes a magnetic yoke 7 and, instead of the magnetic shield 4, has two divided magnetic shields 4A and 4B as the first soft magnetic body.

Thus, in the current sensor 1C (FIG. 8) as the third modified example, compared with the current sensor 1 (FIG. 1, etc.), the measurement error caused by the relative positional deviation between the magnetic detection unit 2 and the conductor 5 is reduced. can be further reduced. Furthermore, the detection sensitivity of the current Im in the magnetic detection section 2 can be further enhanced. Further, since the magnetic flux density of the magnetic flux Bm imparted to the magnetic detection section 2 is improved, instead of the MR element as the magnetic detection element section 20 of the magnetic detection section 2, a Hall element or the like, which generally has lower sensitivity than the MR element, can be used. It can also be used, and the degree of freedom in design is improved. In addition, in the current sensor 1C (FIG. 8), an effect of reducing the influence of magnetic noise (disturbance magnetic field) in the Y-axis direction on the magnetic detection unit 2 was also recognized. Also in the current sensor 1C, a portion of the magnetic shield 4A and a portion of the magnetic shield 4B may be connected. However, in that 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 showing 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 portion 43A of the first wall portion 42A opposite to the bottom portion 41 and a second wall portion 42B of the second wall portion 42B opposite to the bottom portion 41. The upper end portions 43B are bent in a direction toward each other, that is, inward. The configuration of the current sensor 1D is substantially the same as the configuration 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 portion 43A and the second upper end portion 43B is preferably larger than the width W5 (W43>W5). This is because the operation of attaching the current sensor 1D to the vicinity of the conductor 5 is facilitated.
Here, the first upper end portion 43A is a specific example corresponding to the "first upper end portion" of the present invention, and the second upper end portion 43B is a specific example corresponding to the "second upper end portion" of the present invention. .

Thus, in the current sensor 1D (FIG. 9) as the fourth modified example, 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 to the current sensor 1 (FIG. 1, etc.), it is possible to reduce the influence of the magnetic noise (disturbance magnetic field) especially in the X-axis direction on the magnetic detection unit 2, and it is possible to further improve the measurement accuracy. .

[2.5 Modification 5]
FIG. 10 is a schematic cross-sectional view showing a current sensor 1E as a fifth modification (modification 5) of the first embodiment. The current sensor 1E further adds a magnetic yoke 7 to the configuration of the current sensor 1D of FIG. It is designed to Therefore, compared to the current sensor 1 (FIG. 1, etc.), the influence of magnetic noise (disturbance 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 improved. can be further enhanced. Further, since the gap 41S is provided, the detection sensitivity of the current Im in the magnetic detection section 2 can be further enhanced.

<3. Second Embodiment>
FIG. 11 is a block diagram showing a configuration example of an electric control device including the current sensor 1 and the like. All of the current sensors 1, 1A to 1E described in the first embodiment and some modifications can be mounted on 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 the current Iout output from the power supply device 112 or the current Iin input to the power supply device 112 . Although two current sensors 111 are arranged in FIG. 11, the current sensor 111 may be arranged only in one of them. Information about the current value measured by the current sensor 111 is transmitted to the control circuit 113 . The control circuit 113 is a device that controls the operation of the current sensor 111 and the operation of the power supply device 112, for example. The control circuit 113 adjusts the output current from the power supply device 112 based on information from the current sensor 111, for example. The current sensor 111 can be applied to the current sensors 1, 1A to 1E described in the above embodiments. Examples of the electric control device of the present invention include battery management systems, inverters and converters for hybrid electric vehicles (HEVs) and electric vehicles (EVs).

<4. Example>
Next, the performance of the current sensor 1 of the first embodiment shown in FIG. A comparison was made with the performance of 1E.

(Example 1-1)
Regarding the current sensor 1 of the first embodiment, the intensity of the magnetic flux Bm applied to the center position of the magnetic detection unit 2 when a current Im of 600 A is passed through the conductor 5, and the influence of magnetic noise in the Y-axis direction , the influence of magnetic noise in the X-axis direction, and the resistance to positional deviation were obtained by simulation. Here, the dimensions of each portion of the conductor 5 and the magnetic shield 4 are as shown in FIG. The center position of the magnetic detection part 2, which is the measurement point, was set at a height of 1.5 mm from the surface of the bottom part 41. FIG. The influence of magnetic noise in the Y-axis direction is the output error when there is an external magnetic field of 1 mT in the Y-axis direction. The influence of magnetic noise in the X-axis direction is the output error when there is an external magnetic field of 1 mT in the X-axis direction. The positional displacement resistance means the maximum output error when the magnetic detection unit 2 is displaced from the reference position by 0.3 mm in each of the X-axis direction, Y-axis direction and Z-axis direction.

(Example 1-2)
The performance of the current sensor 1A of Modification 1 of the first embodiment was obtained in the same manner as in Example 1-1. However, the material of the magnetic yoke 7 was the same as that of the magnetic shield 4, the dimension of the magnetic yoke 7 in the X-axis direction was 12 mm, and the dimension of the magnetic yoke 7 in the Y-axis direction was 1.5 mm. Also, the magnetic yoke 7 is assumed to exist at an intermediate position between the bottom portion 41 and the magnetic shield 4 .

(Example 1-3)
The performance of the current sensor 1B of Modification 2 of the first embodiment was obtained in the same manner as in Example 1-1. However, the width of the gap 41S was set to 2 mm.

(Example 1-4)
The performance of the current sensor 1C of Modification 3 of the first embodiment was obtained in the same manner as in Example 1-1. However, the material of the magnetic yoke 7 was the same as that of the magnetic shield 4, the dimension of the magnetic yoke 7 in the X-axis direction was 12 mm, and the dimension of the magnetic yoke 7 in the Y-axis direction was 1.5 mm. Also, the magnetic yoke 7 is assumed to exist at an intermediate position between the bottom portion 41 and the magnetic shield 4 . The width of the gap 41S was set to 2 mm.

(Example 1-5)
The performance of the current sensor 1E of Modification 5 of the first embodiment was obtained in the same manner as in Example 1-1. However, the material of the magnetic yoke 7 was the same as that of the magnetic shield 4, the dimension of the magnetic yoke 7 in the X-axis direction was 12 mm, and the dimension of the magnetic yoke 7 in the Y-axis direction was 1.5 mm. Also, the magnetic yoke 7 is assumed to exist at an intermediate position between the bottom portion 41 and the magnetic shield 4 . The width of the gap 41S was set to 2 mm. Furthermore, the interval W43 between 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 was set to 14 mm.

FIG. 13 summarizes the performance of each current sensor of Examples 1-1 to 1-5. However, in FIG. 13, the characteristic value of each parameter in Example 1-1 is normalized to 1, and each performance of Examples 1-2 to 1-5 is shown. It should be noted that the higher the numerical 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, which is desirable. It is desirable that the numerical value of the misalignment resistance is also low.

As shown in FIG. 13, in Example 1-2, compared with Example 1-1, each performance of the magnetic flux Bm, the magnetic noise in the X-axis direction, and the magnetic noise in the Y-axis direction is low. It can be seen that the tolerance is improved. That is, it was confirmed that by providing the magnetic yoke, it was possible to improve the resistance to displacement.

As shown in FIG. 13, in Example 1-3, compared to Example 1-1, although it is more susceptible to magnetic noise in the X-axis direction, the performance of magnetic noise in the Y-axis direction and resistance to misalignment is found to be improving. Furthermore, it was confirmed that the strength of the magnetic flux Bm imparted to the magnetic detection section 2 was greatly improved. That is, it was confirmed that performance other than the magnetic noise in the X-axis direction could be improved by using the magnetic shield provided with the gap.

As shown in FIG. 13, in Example 1-4, as compared with Example 1-3, the strength of the magnetic flux Bm is lower, but the performance of resistance to position deviation is further improved.

As shown in FIG. 13, in Example 1-5, compared with Example 1-4, the strength of the magnetic flux Bm, the magnetic noise in the X-axis direction, and the resistance to positional deviation can be improved. Recognize.

(Examples 2-1 to 2-3)
Next, regarding the current sensor 1 of the first embodiment, the effect on each performance when changing the position of the conductor 5 in the Y-axis direction was obtained by simulation. The configuration of Example 2-1 is the same as that of Example 1-1 except that the distance between the bottom portion 41 and the conductor 5 is set to 3.0 mm. The configuration of Example 2-2 is the same as that of Example 1-1, except that the distance between the bottom portion 41 and the conductor 5 is set to 9.0 mm. The configuration of Example 2-3 is the same as that of Example 1-1 except that the distance between the bottom portion 41 and the center position of the magnetic detecting portion 2, which is the detection point, is 4.5 mm.

FIG. 14 summarizes the performance of each current sensor of Examples 2-1 to 2-3 together with the results of Example 1-1. However, FIG. 14 normalizes the characteristic value of each parameter of Example 1-1 to 1, and shows the performance of Examples 2-1 to 2-3.

As shown in FIG. 14, in Example 2-1 in which the conductor 5 is brought closer to the bottom portion 41, the intensity of the magnetic flux Bm applied to the magnetic detection unit 2 is improved compared to Example 1-1. , the magnetic noise in the X-axis direction and the magnetic noise in the Y-axis direction are also improved. However, it was found that Example 1-1 was better than Example 2-1 in terms of misalignment resistance.

On the other hand, in Example 2-2 in which the conductor 5 is kept away from the bottom portion 41, compared with Example 1-1, the intensity 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 It can be seen that each performance of directional magnetic noise is degraded. However, it was found that Example 2-2 was better than Example 1-1 in terms of misalignment resistance.

In addition, in Example 2-3 in which the magnetic detection unit 2 is moved away from the bottom part 41 (that is, brought closer to the conductor 5), the strength of the magnetic flux Bm is improved compared to Example 1-1, and the magnetic flux in the X-axis direction is improved. It can be seen that each performance of noise and magnetic noise in the Y-axis direction is also improved. However, it can be seen that the misalignment resistance is lower than in Examples 1-1 and 2-1.

(Examples 3-1 to 3-2)
Next, regarding the current sensor 1E of Modification 5 of the first embodiment, the effect on each performance when the width of the magnetic yoke 7 is changed was obtained by simulation. The configuration of Example 3-1 is the same as the configuration of Example 1-5 except that the width of the magnetic yoke 7 is narrower than the width of the conductor 5. FIG. The configuration of Example 3-2 is the same as the configuration of Example 1-5 except that the width of the magnetic yoke 7 is made wider than the width of the conductor 5. FIG.

FIG. 15 summarizes the performance of each current sensor of Examples 3-1 and 3-2 together with the results of Example 1-5. However, FIG. 15 normalizes the characteristic value of each parameter of Example 1-5 to 1, and shows each performance of Examples 3-1 and 3-2.

As shown in FIG. 15, in Example 3-1 in which the width of the magnetic yoke 7 is narrower than the width of the conductor 5, the strength of the magnetic flux Bm is slightly improved compared to Example 1-5. , the misalignment resistance is reduced. On the other hand, in Example 3-2, in which the width of the magnetic yoke 7 is made wider than the width of the conductor 5, the strength of the magnetic flux Bm is slightly lower than that of Example 1-5, but the resistance to displacement is improved. found to do.

(Examples 4-1 to 4-2)
Next, regarding the current sensor 1C of Modification Example 3 of the first embodiment, each performance when the first wall portion 42A of the magnetic shield 4A and the second wall portion 42B of the magnetic shield 4B are each inclined. The effect on the The configuration of Example 4-1 is the same as that of Example 1-4 except that the first wall portion 42A and the second wall portion 42B of the magnetic shield 4B are each inclined outward. The configuration of Example 4-2 is the same as that of Example 1-4 except that the first wall portion 42A and the second wall portion 42B of the magnetic shield 4B are each inclined inward.

FIG. 16 summarizes the performance of each current sensor of Examples 4-1 and 4-2 together with the results of Examples 1-4 and 1-5. However, FIG. 16 normalizes the characteristic value of each parameter of Example 1-1 to 1, and shows the performance of Examples 4-1, 4-2, 1-4, and 1-5.

As shown in FIG. 16, in Example 4-1, compared with Example 1-4, the strength of the magnetic flux Bm is slightly improved and the influence of magnetic noise in the X-axis direction is improved. It was found that resistance performance was reduced. On the other hand, in Example 4-2, compared with Example 1-4, it was found that each performance of magnetic noise in the X-axis direction and resistance to misalignment were both lowered.

The embodiments and modifications described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments and the like is meant to include all design changes and equivalents that fall within the technical scope of the present invention. That is, the present invention is not limited to the above embodiments and the like, and various modifications are possible.

For example, the current sensor 1 (FIGS. 1 to 3) of the above embodiment exemplifies a structure in which the first wall portion 42A and the second wall portion 42B are in physical contact with the bottom portion 41 of the magnetic shield 4. The invention is not limited to this. For example, the bottom portion 41 and at least one of the first wall portion 42A and the second wall portion 42B may be physically separated. 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 if they are not in physical contact.

In addition, in the current sensor 1 (FIGS. 1 to 3) of the above embodiment, the connection portions between the bottom portion 41 of the magnetic shield 4 and the first wall portion 42A and the second wall portion 42B are curved. have a shape. However, the invention is not limited to this aspect. For example, the connecting portions may have a curved shape or a chamfered shape with chamfered corners.

In addition, the present invention is not limited to a mode in which the current sensor is attached to the conductor through which the current to be detected flows. It is a concept that also includes

DESCRIPTION OF SYMBOLS 1... Current sensor 2... Magnetic detection part 20... Magnetic detection element part 60... Signal processing part 3... Housing 4... Magnetic shield 41... Bottom part 42A... First wall part 42B... Second wall Part 5... Conductor 6... Screw 7... Magnetic yoke Bm... Magnetic flux Im... Current.

Claims (13)

a magnetic detection unit to which a magnetic flux in a second direction generated by a current flowing through the conductor along the first direction is applied;
a bottom located on the side opposite to the conductor when viewed from the magnetic detection section in a third direction perpendicular to the first direction; A current sensor comprising: a first soft magnetic body having a first wall portion and a second wall portion that are arranged to face each other so as to sandwich the first wall portion and the second wall portion. The current sensor according to claim 1, further comprising a second soft magnetic body provided between the conductor and the magnetic detection section. The current sensor according to claim 2, wherein the dimension of the second soft magnetic body in the second direction is larger than the dimension of the conductor in the second direction. The current sensor according to any one of claims 1 to 3, wherein the first soft magnetic body includes a first portion and a second portion that are spaced apart and face each other in the second direction. 5. The current sensor according to claim 4, wherein the magnetic detector is positioned so as to overlap the gap between the first portion and the second portion in the third direction. A first upper end portion of the first wall portion opposite to the bottom portion and a second upper end portion of the second wall portion opposite to the bottom portion are curved toward each other. The current sensor according to any one of claims 1 to 5. A first distance from the bottom to a first top of the first wall and a second distance from the bottom to a second top of the second wall are each greater than a third distance between the bottom and the conductor. The current sensor according to any one of claims 1 to 6, which is two times or more. 8. The current sensor of claim 7, wherein the fourth distance between the bottom and the magnetic sensing portion is less than half the third distance between the bottom and the conductor. Further comprising a housing including a pair of recesses arranged in the first direction,
The current sensor according to any one of claims 1 to 8, wherein the pair of recesses are configured to be fittable with the conductor. The current sensor according to claim 9, wherein the conductor, the magnetic detection section, and the first soft magnetic body are electrically insulated by the housing. An electric control device comprising the current sensor according to any one of claims 1 to 10. a conductor;
a magnetic detection unit to which a magnetic flux in a second direction generated by a current flowing through the conductor along the first direction is applied;
a bottom located on the side opposite to the conductor when viewed from the magnetic detection section in a third direction perpendicular to the first direction; A current sensor module comprising: a first soft magnetic body having a first wall portion and a second wall portion that are arranged to face each other so as to sandwich the first wall portion and the second wall portion. A method for manufacturing a current sensor module comprising: a conductor; a magnetic detection unit to which a magnetic flux in a second direction generated by a current flowing through the conductor in a first direction is applied; a first soft magnetic body; ,
A bottom portion that extends along the first direction and the second direction; providing the first soft magnetic body having two walls;
preparing the housing including a pair of recesses arranged in the first direction and provided with the first soft magnetic body and the magnetic detection unit;
A method of manufacturing a current sensor module, comprising fitting the conductor into the pair of recesses.

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