Current detector

Abstract

To provide a current detector capable of detecting a current with high accuracy by cooling heat generated when a current to be detected is applied to a conductor.SOLUTION: In a conductor 1 that is fixed in a posture of penetrating a housing 8 and extends in a Z direction, a cooling plate 2, which is fixed to a housing 8 and has a fastening part 3, is arranged so that the fastening part 3 extends in an X direction at a position in which the fastening part does not overlap the housing, thereby fixing and connecting the fastening part 3 to a cooler 10.SELECTED DRAWING: Figure 2-1

Description

[Technical Field]

[0001] The present invention relates to a current detection device. [Background technology]

[0002] In recent years, electric vehicles and hybrid vehicles have become increasingly popular, and in order to control the motors of these vehicles, it is important to accurately detect the current flowing through the motor.To detect this current, current detection devices such as current sensors equipped with detection elements such as Hall elements and magnetoresistive elements are used.

[0003] However, in recent years, SiC, which has high voltage resistance and low switching loss, has been used as the power semiconductor for inverters, and as a result, the current flowing through motors has tended to increase.When the current flowing through a motor increases, the primary conductor through which the current flows generates a lot of heat, and the current sensor that detects this current is also affected by the heat generated by the primary conductor, causing the location where the detection element is located to become very hot.

[0004] In recent years, there has been a demand for smaller and thinner current sensors, and coreless current sensors, which do not have a magnetic core and in which the detection element directly detects the magnetic flux generated by the current flowing through the primary conductor, are being used.However, since there is no magnetic core, the amount of magnetic flux density detected by the detection element is small.In order to increase the amount of magnetic flux density detected, measures have been taken to reduce the cross-sectional area of ​​the primary conductor or to place the detection element close to the primary conductor, but this results in a large amount of heat generation from the primary conductor or the detection element being placed in a position that is susceptible to the effects of heat generation.

[0005] When the operating environment becomes hot, the characteristics of the detection element change, which affects the accuracy of detecting the current flowing through the motor. Therefore, in the past, the primary conductor was directly connected to another component with cooling function, thereby directly cooling the primary conductor.

[0006] For example, Patent Document 1 proposes a current sensor structure that uses an inverter with a cooling function and places the core and detection element of the detection phase through which the maximum current flows on the inverter side, thereby unifying the cooling function and enabling high-precision current detection. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2018-207726 Summary of the Invention [Problem to be solved by the invention]

[0008] Since the primary conductor is directly connected to the inverter with cooling function, this is the most efficient cooling method. However, if the current sensor is large or has a complex structure, the distance from the inverter with cooling function to the detection element may be long, resulting in insufficient cooling. As a result, the detection element may be affected by heat generation, which may result in a decrease in the accuracy of current detection.

[0009] In view of the above problems, the present invention proposes a current sensor structure that has a cooling method different from conventional cooling methods by providing a new cooling path.

[0010] [Means for solving the problem]

[0011] A current detection device that is connected to and fixed to a cooler, and in which heat generated when a current to be detected is applied is cooled by the cooler, comprises a conductor to which the current to be detected is applied, a detection unit that detects the current to be detected, a cooling plate that transfers heat when a current flows through the conductor and has at least one fastening unit, the conductor, the detection unit, and a housing to which the cooling plate is fixed and formed of a material having a lower thermal conductivity than the cooling plate, wherein the conductor penetrates the inside of the housing and is fixed to the housing, the cooling plate is positioned on the underside in the extension direction of the conductor, extends in a direction perpendicular to the extension direction of the conductor, and is fixed to the housing in a position where the fastening unit does not overlap with the housing, and is connected to and fixed to the cooler by the fastening unit. [Effects of the Invention]

[0012] According to the present invention, it is possible to cool the heat generated in a conductor when a current to be detected is applied to a current detector using a cooling method different from conventional methods, thereby suppressing the effects of the heat generated in the conductor and achieving more accurate current detection. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of a current sensor 100 according to a first embodiment of the present invention. [Figure 2] 2 is a schematic diagram illustrating a cooling function of the current sensor 100 according to the first embodiment of the present invention. FIG. [Figure 3] 10A and 10B are schematic diagrams showing examples of modified shapes of the conductor 1 and the cooling plate 2 of the current sensor 100 according to the first embodiment of the present invention. [Figure 4] 3 is a schematic diagram showing an example of a modification of the arrangement of the cooling plate 2 of the current sensor 100 according to the first embodiment of the present invention. FIG. [Figure 5] FIG. 10 is a schematic diagram of a current sensor 200 according to a second embodiment of the present invention. [Figure 6] FIG. 10 is a schematic diagram of a current sensor 300 according to a third embodiment of the present invention. [Figure 7] FIG. 10 is a schematic diagram of a current sensor 400 according to a fourth embodiment of the present invention. [Figure 8]FIG. 10 is a schematic diagram of a current sensor 500 according to a fifth embodiment of the present invention. [Figure 9] FIG. 10 is a schematic diagram of a shunt sensor 600 according to a fifth embodiment of the present invention. [Figure 10] 1 is a schematic diagram of a current sensor 100 used in a simulation to demonstrate the cooling effect of the present invention. [Figure 11] 10 is a table showing the results of a simulation. DETAILED DESCRIPTION OF THE INVENTION Embodiment 1

[0014] Figure 1 is a schematic diagram of a current sensor 100 according to a first embodiment of the present invention, where Figure 1(a) is an oblique view of the current sensor 100, Figure 1(b) is an exploded front view of the current sensor 100, Figure 1(c) is a plan view of the current sensor 100, and Figure 1(d) is a cross-sectional view showing section A-A in Figure 1(c). In addition, in all embodiments of the present invention, unless otherwise specified, the width direction of a rectangular conductor is defined as the X direction, the thickness direction of the conductor is defined as the Y direction, the extension direction of the conductor is defined as the Z direction, and the direction of the illustrated arrow is defined as the + (positive) direction.

[0015] In FIG. 1, the current sensor 100 includes three rectangular conductors 1 to which three different three-phase AC currents to be detected are applied, a cooling plate 2 having two fastening portions 3, three magnetic sensors 5 each having a magnetoelectric conversion element M for detecting magnetic flux generated when the currents to be detected are applied, a substrate 4 on which output terminals 6 are mounted for outputting to the outside an output signal outputted in accordance with the amount of magnetic flux density detected by the magnetic sensors 5, two tapping screws 7 for fixing the substrate 4, and a housing 8 to which the three conductors 1, the cooling plate 2, and the substrate 4 are fixed. The conductors 1 are arranged in a row in the X direction, penetrate the inside of the housing 8, and are fixed to the housing 8 in a position extending in the Z direction. The cooling plate 2 is located below (in the Y- direction) the direction in which the current to be detected is applied to each conductor 1, and is fixed to the housing 8 in a position where it extends in the X- direction, with two fastening parts 3 not overlapping with the housing 8. The substrate 4 is arranged from the Y+ direction to the Y- direction so as to contact two substrate bases 9 on the housing 8. At this time, the magnetic sensors 5 are located on the upper side (in the Y+ direction) of the conductors 1 of the U-phase, V-phase, and W-phase, respectively, and are arranged so as to overlap with the cooling plate 2 when viewed from the Y direction. Two screws 7 pass through screw through holes in the substrate 4 (not shown), and are screwed into pilot holes for tapping screws in the housing 8 (not shown) in the Y+ direction to the Y- direction, and are fixed to the housing 8.

[0016] Conductor 1 is a metal conductor to which a current to be detected (not shown) is applied in the Z+ direction from current application surfaces U, V, and W of the U, V, and W phases, respectively, and is made of a metal with high conductivity such as copper or aluminum. As long as the current to be detected is applied, the type of material used does not matter, and the surface may be plated or the like.

[0017] In the current sensor 100, the conductor 1 extends in a rectangular shape as shown in Fig. 1, but is not limited to this and may have a notched or bent shape (examples of changes to the shape of the conductor 1 will be described later).

[0018] The cooling plate 2 has the role of transferring Joule heat generated when a current to be detected (not shown) is applied to each conductor 1, and is made of a non-magnetic metal such as copper or aluminum that has high thermal conductivity, or a resin that has high thermal conductivity.The type of material does not matter as long as it has a higher thermal conductivity than the housing 8, and if it is made of metal, the surface may be plated or the like.

[0019] In the current sensor 100, as shown in FIG. 1, the cooling plate 2 has a rectangular shape, is located below the extension direction of each conductor 1 (Y-direction), and is arranged extending in the X-direction at a position overlapping with the magnetic sensor 5 when viewed from the Y-direction. However, this is not limited to this. As long as it is positioned within the extension range of each conductor 1 in the Z direction when viewed from the Y direction and extends in the X direction, it may have a notched shape, a bent shape, or a divided shape, and may also be positioned on the upper surface side (Y+ direction) in the extension direction of each conductor 1, or may be positioned so as not to overlap with the magnetic sensor 5 when viewed from the Y direction. (Examples of changes in the shape and arrangement of the cooling plate 2 will be described later.)

[0020] In the current sensor 100, the fastening portion 3 is formed in a circular shape so as to penetrate a part of the cooling plate 2, but this is not limited to this and it may be rectangular, or may be made up of a separate part and attached to the cooling plate 2.

[0021] The substrate 4 is made of a common substrate material such as glass epoxy or phenol, and the magnetic sensor 5 and output terminal 6 are mounted on the substrate 4 by soldering or the like.

[0022] The magnetic sensor 5 is a magnetic detection device such as an SOP-type or SIP-type IC that has a magnetoelectric conversion element M that detects the magnetic flux generated when a current to be detected is applied to the conductor 1, and outputs an output signal according to the amount of magnetic flux density detected by the magnetoelectric conversion element M. The magnetoelectric conversion element M can be of any type, such as a Hall effect element or a magnetoresistance effect element. In the current sensor 100, the magnetoelectric conversion element M is arranged so that its magnetic sensing direction is the X+ direction, and when a current to be detected is applied to each conductor 1, the element detects the amount of magnetic flux density in the X+ direction and outputs an output signal according to the detected amount of magnetic flux density.

[0023] The output terminal 6 is a terminal for outputting to the outside an output signal that is output in accordance with the amount of magnetic flux density detected by the magnetoelectric conversion element M, and has a shape with five pins in the current sensor 100, but a general connector or the like may also be used. The number of output terminals may also be changed as desired.

[0024] The substrate 4 also has an analog circuit (not shown) which is composed of an operational amplifier, a capacitor, a resistor, ferrite beads, etc., and the output signal output according to the amount of magnetic flux density detected by the magnetic sensor 5 is output to the outside via the analog circuit (not shown) and output terminal 6.

[0025] The screws 7 are fasteners such as tapping screws made of iron or aluminum, and the material and shape of the screws 7 are not important as long as they can fasten the substrate 4. Although screws may be used as in the current sensor 100, the screws 7 may be eliminated and the substrate 4 may be fastened using heat welding, adhesive, or the like.

[0026] The housing 8 is a resin housing made of a thermoplastic resin such as PPS, PBT, or PA.

[0027] The conductor 1 and the cooling plate 2 may be fixed to the housing 8 by insert molding, whereby the conductor 1 and the cooling plate 2 are simultaneously molded when the housing 8 is formed by injection molding, or the housing 8 may be formed in sections, and then the conductor 1 and the cooling plate 2 may be assembled and fixed in a position where they penetrate the interior of the housing 8. In the current sensor 100, the cooling plate 2 is disposed in a position where it penetrates the interior of the housing 8, but this is not limited thereto, and the cooling plate 2 may be fixed so that it is in contact with the housing 8.

[0028] In addition, in the current sensor 100, the conductor 1 and the cooling plate 2 are arranged in a position that penetrates the inside of the housing 8, and at the part that penetrates the housing 8, they are completely buried inside the housing 8, but this is not limited to this, and the conductor 1 and the cooling plate 2 may also be configured so that they are partially exposed from the housing 8.

[0029] The current sensor 100 configured in this manner has the function of cooling the heat generated by Joule heat when a current to be detected (not shown) is applied to the current application surfaces U, V, and W of the conductors 1 of the U, V, and W phases with the fastening portion 3 connected and fixed to the cooler. This cooling function and effect will be described.

[0030] Figure 2 is a schematic diagram explaining the cooling function of the current sensor 100 relating to embodiment 1 of the present invention, where Figure 2(a) is an oblique view of the current sensor 100 when connected to a cooler, Figure 2(b) is an oblique view of the current sensor 100 when connected to a cooler, Figure 2(c) is a plan view of Figure 2(b), and Figure 2(d) is a cross-sectional view of the current sensor 100 at section B-B in Figure 2(c).

[0031] 2 shows a schematic diagram of the current sensor 100 when and after it is connected to the cooler 10. The cooler 10 is made of a cooling housing 11 formed of metal or resin and having a flow path 11a through which a cooling solvent (not shown) flows, and a cooling terminal 12 having a threaded cooling fastening part 12a formed of metal. The current sensor 100 is placed so that the fastening part 3 of the cooling plate 2 contacts the cooling terminal 12, and then fastened to the cooling fastening part 12a with a bolt 13, thereby connecting the cooler 10 and the current sensor 100 and fixing the current sensor 100. A cooling solvent (not shown) flows through the flow path 11a in the direction of the arrow in FIG. 2(d), which is the direction of the cooling solvent flow.

[0032] When a current to be detected (not shown) is applied in the Z+ direction to the current application surface U, current application surface V, and current application surface W of each conductor 1 of each detection phase U, V, and W of the current sensor 100 connected and fixed to the cooler 10 in this manner, each conductor 1 generates heat due to Joule heat. As shown in Figure 2(d), since the cooling plate 2 is located below (in the Y-direction) each conductor 1, which is the heat source, the heat T generated by the heat generation is transferred to the cooling plate 2 via the housing 8, the heat T transferred to the cooling plate 2 is transferred within the cooling plate 2 to the cooling terminal 12, and the heat T transferred to the cooling terminal 12 is transferred to the cooling solvent (not shown) via the cooling housing 11, thereby forming a heat transfer path 14, and when the current to be detected is applied, the heat generated from each conductor 1 is cooled through the cooling plate 2, making it possible to prevent the temperature around the magnetic sensor 5 from rising too high. (The quantitative effects of the invention will be described later using simulations.)

[0033] 2 is configured so that a cooling medium (not shown) flows through the flow path 11a. Alternatively, a fastening portion may be provided on an aluminum case surrounding an inverter that is cooled by air, water, or a circulating fluid, and the fastening portion of the aluminum case may be directly connected to the fastening portion 3. Such a configuration makes it possible to obtain the cooling function at a lower cost. In other words, it should be noted that the cooler of the present invention is configured to have a fastening portion to which the fastening portion 3 of the current sensor 100 can be connected and fixed, and which is maintained at a temperature lower than the heat generated by each conductor 1 by a cooling means such as air or water cooling.

[0034] In addition, in conventional current sensors, when fixing the current sensor itself, fixing collars or bushes are used on the plastic casing, but in current sensor 100, since the cooling plate 2 has a fastening portion 3, there is no need to prepare fixing collars or bushes, and current sensor 100 can be fixed at the fastening portion 3, making it possible to achieve the cooling function at a lower cost.

[0035] Furthermore, by combining the cooling function of current sensor 100 with the cooling method of a conventional inverter with a cooling function, a higher cooling effect can be achieved, making it possible to apply current values ​​that cannot be applied with conventional current sensors, which contributes to improving the driving performance of electric vehicles and hybrid vehicles.

[0036] Furthermore, the current sensor 100 according to the first embodiment of the present invention has an additional effect of improving the dimensional accuracy of the current sensor 100. This is because the cooling plate 2 extends in a direction (X direction) perpendicular to the extension direction (Z direction) of each conductor 1, and therefore, when the current sensor 100 is molded by inserting the conductors 1 and the cooling plate 2 by injection molding, for example, the cooling plate 2 acts as a beam, making it possible to reduce warpage of the housing 8 due to resin shrinkage.

[0037] An example of changing the shape and arrangement of the conductor 1 and the cooling plate 2, which has the same cooling effect as the current sensor 100 according to the first embodiment of the present invention, will be described.

[0038] Figures 3 and 4 are schematic diagrams showing examples of shape and arrangement changes of the conductor 1 and cooling plate 2 of the current sensor 100 relating to embodiment 1 of the present invention, where Figure 3(a) is an oblique view of the internal structure showing an example of shape change of the conductor 1, Figure 3(b) is an oblique view of the internal structure showing an example of shape change of the conductor 1, Figure 3(c) is an oblique view of the internal structure showing an example of shape change of the cooling plate 2, Figure 3(d) is an oblique view of the internal structure showing an example of shape change of the cooling plate 2, Figure 4(a) is an oblique view of the current sensor 101 showing an example of arrangement change of the cooling plate 2, Figure 4(b) is a right side view showing an exploded view of the current sensor 101 shown in Figure 4(a), and Figure 4(c) is an oblique view of the internal structure of the current sensor 101 shown in Figure 4(a).

[0039] 3(a)(b)(c)(d) and 4(c) are perspective views showing the internal structure of a configuration in which the shape and arrangement of the conductor 1 and the cooling plate 2 have been changed, and which show only the conductor 1 and the cooling plate 2.

[0040] As shown in FIGS. 3(a) and 3(b), the conductor 1 may have a shape like conductor 1A having a notched portion 1a, or may have a shape like conductor 1B having a bent portion 1b in the Y direction.

[0041] As shown in Figure 3(c), the cooling plate 2 may be shaped like a cooling plate 2A having a cutout portion 2a, or as shown in Figure 3(d), a divided shape may be used, such as using two cooling plates 2B each having one fastening portion 3.

[0042] 4, the cooling plate 2 may be located within the Z-direction extension range of each conductor 1 and extend in the X-direction, and in current sensor 100, it is located on the underside (Y-direction) of conductor 1 and extends in the X-direction with the magnetic sensor 5 overlapping with the cooling plate 2 when viewed from the Y-direction, but as in current sensor 101, it may be located on the upper side (Y+ direction) of conductor 1 and extend in the X-direction with no overlap with the magnetic sensor 5 when viewed from the Y-direction. Furthermore, the housing 8A of current sensor 101 is larger in size in the Z+ direction than current sensor 100 due to the change in the position of the cooling plate 2, and the cooling plate 2 is fixed to the housing 8A with the two fastening parts 3 arranged so as not to overlap with the housing 8A.

[0043] Even if the shape and arrangement of the conductor 1 and cooling plate 2 are changed, the cooling effect may increase or decrease slightly, but the cooling function will not be lost. It is possible to cool the heat generated by the current being detected in a way that is different from conventional current sensors, thereby suppressing the effects of heat generation in the conductor and contributing to achieving more accurate current detection.

[0044] 3 and 4 are merely examples of possible configurations of the conductor 1 and cooling plate 2, and do not limit the present invention. It should be noted that configurations that combine multiple modifications, or additional modifications such as convex, concave, or bent shapes, are also within the scope of the present invention.

[0045] Current sensor 100 according to the first embodiment of the present invention has been described using a minimum necessary configuration for a current sensor, which uses a magnetoelectric conversion element to detect magnetic flux generated from a current to be detected. However, the present invention can also be applied to current sensors having different configurations and current detection devices using detection methods other than magnetic flux. (In the following embodiments of the present invention, components common to current sensor 100 according to the first embodiment of the present invention will be designated by the same reference numerals, and descriptions thereof will be omitted.) DETAILED DESCRIPTION OF THE INVENTION Embodiment 2

[0046] FIG. 5 is a schematic diagram of a current sensor 200 according to a second embodiment of the present invention, and is a diagram showing the current sensor 200 in a manner equivalent to FIG. 1(d).

[0047] The current sensor 200 is equipped with a magnetic sensor 5A having magnetoelectric conversion elements Ma and Mb that detect the magnetic flux generated when a current to be detected is applied to the conductor 1, and a differential calculation unit not shown.The magnetic sensor 5A is a magnetic detection device such as an SOP-type IC, and performs differential calculation on output signals corresponding to the magnetic flux density detected by the magnetoelectric conversion elements Ma and Mb in the differential calculation unit not shown, and outputs the differential calculation value.

[0048] 5, current sensor 200 is configured such that magnetic sensor 5A is arranged on the upper surface (Y+ direction) of conductors 1 of U-phase, V-phase, and W-phase, respectively, when substrate 4 is fixed to housing 8, in a position overlapping cooling plate 2 when viewed from the Y direction. At this time, magnetoelectric conversion elements Ma and Mb are located on the upper surface (Y+ direction) of the conductors, and are arranged side by side in the X direction across a virtual center line of the width dimension (X direction dimension) of each conductor (not shown), and are arranged in an attitude in which their magnetic sensing direction is the Y+ direction.

[0049] In current sensor 200 configured in this manner, when a current to be detected (not shown) is applied to each conductor 1, output signals output in accordance with the amount of magnetic flux density detected by magnetoelectric conversion elements Ma and Mb are differentially calculated by a differential calculation unit (not shown), and the differential calculation value is output as an output signal from magnetic sensor 5A and output to the outside via substrate 4 and an output terminal (not shown). (At this time, since the amount of magnetic flux density detected by magnetoelectric conversion element Ma and the amount of magnetic flux density detected by magnetoelectric conversion element Mb are values ​​with different positive and negative signs, the amount of magnetic flux density obtained by adding both values ​​is detected by differential calculation.) A similar cooling effect can be expected in current sensor 200 configured in this manner as well. DETAILED DESCRIPTION OF THE INVENTION Embodiment 3

[0050] Figure 6 is a schematic diagram of a current sensor 300 relating to embodiment 3 of the present invention, where Figure 6(a) is a diagram showing the current sensor 300 in a view equivalent to Figure 1(d), Figure 6(b) is an oblique view showing the internal structure of the current sensor 300, showing only the conductor 1, cooling plate 2 and magnetic core 15 of the current sensor 300, Figure 6(c) is a diagram showing a current sensor 301 having a magnetic core of a different shape from the current sensor 300 in a view equivalent to Figure 1(d), and Figure 6(d) is an oblique view showing the internal structure of the current sensor 301, showing only the conductor 1, cooling plate 2 and magnetic core 16 of the current sensor 301.

[0051] 6(a) and 6(b), the current sensor 300 includes a magnetic sensor 5B having a magnetoelectric transducer Mc that detects the magnetic flux generated when a current to be detected is applied to the conductor 1; three magnetic cores 15 formed of a magnetic material and having a substantially C-shaped air gap 15a and a core gap 15b; and a housing 8B having three insertion holes 8b into which the magnetic sensor 5B is inserted. The magnetic sensor 5B is a magnetic detection device such as an SIP-type IC that outputs an output signal according to the amount of magnetic flux density detected by the magnetoelectric transducer Mc. The magnetic cores 15 are general laminated cores or pressed powder cores made of a magnetic material such as silicon steel plate or ferrite, and are fixed inside the housing 8B by insert molding or assembly. (When the magnetic cores 15 are fixed to the housing 8B by assembly, the housing 8B may be formed in sections.)

[0052] As shown in Figures 6(a) and (b), the current sensor 300 has the magnetic core 15 arranged in a position where different conductors 1 pass through the gap 15a, and the magnetic sensor 5B is arranged in the insertion hole 8b of the housing 8B in a position where the magnetoelectric conversion element Mc has a magnetic sensing direction in the X+ direction within the core gap 15b when the substrate 4 is fixed to the housing 8B.

[0053] When a current to be detected (not shown) is applied to each conductor 1 of current sensor 300 configured in this manner, magnetic flux (not shown) is generated and collected by magnetic core 15, forming a magnetic path (not shown) that passes through the interior of magnetic core 15 and core gap 15b, and since magnetoelectric conversion element Mc is disposed within core gap 15b, an output signal corresponding to the detected magnetic flux density is output from magnetic sensor 5B by detecting magnetic flux (not shown) that passes through core gap 15b, and is then output to the outside from substrate 4 and an output terminal (not shown). A similar cooling effect can be expected in current sensor 300 configured in this manner as well.

[0054] Furthermore, although the magnetic core 14 is formed in an approximately C-shape, this is not limitative, and the magnetic core 14 may be formed in an approximately U-shape, as in the current sensor 301 shown in Figures 6(c) and (d).

[0055] As shown in Figures 6(c) and (d), in the current sensor 301, each magnetic core 16 is arranged in a position where a different conductor 1 passes through the gap 16a, and when the substrate 4 is fixed to the housing 8B, the magnetic sensor 5B is arranged in the insertion hole 8b of the housing 8B in a position where the magnetoelectric conversion element Mc has a magnetic sensing direction in the gap 16a in the X+ direction.

[0056] When a current to be detected (not shown) is applied to each conductor 1 of current sensor 301 configured in this manner, a magnetic flux (not shown) is generated, which is collected by magnetic core 16 and forms a magnetic path (not shown) that passes through the interior of magnetic core 16 and gap 16a, and since magnetoelectric conversion element Mc is disposed within gap 16a, it detects magnetic flux in the X direction (not shown) that passes through gap 16a, and an output signal corresponding to the detected magnetic flux density is output from magnetic sensor 5B and then output to the outside from substrate 4 and an output terminal (not shown). A similar cooling effect can be expected in current sensor 301 configured in this manner as well. DETAILED DESCRIPTION OF THE INVENTION Embodiment 4

[0057] Figure 7 is a schematic diagram of a current sensor 400 relating to embodiment 4 of the present invention, where Figure 7(a) is a diagram showing the current sensor 400 in a view equivalent to Figure 1(d), and Figure 7(b) is an oblique view showing the internal structure of the current sensor 400, showing only the conductor 1C and cooling plate 2 of the current sensor 400.

[0058] The current sensor 400 comprises a conductor 1C having a slit 1Ca penetrating in the Y direction, a magnetic sensor 5C having magnetoelectric conversion elements Md and Me and a differential calculation unit (not shown) that detect the magnetic flux generated when a current to be detected is applied to the conductor 1C, and a housing 8C having three insertion holes 8Ca into which the magnetic sensor 5B is inserted. The magnetic sensor 5C is a magnetic detection device such as a SIP-type IC, and outputs an output signal according to the amount of magnetic flux density detected by the magnetoelectric conversion elements Md and Me.

[0059] As shown in Figure 7, when the substrate 4 of the magnetic sensor 5B is fixed to the housing 8B, the current sensor 400 is arranged in an insertion hole 8Ca of the housing 8C with the magnetoelectric conversion element Md and the magnetoelectric conversion element Me facing each other in the Y direction across the slit 1Ca and with their magnetic sensing direction in the X+ direction.

[0060] In current sensor 400 configured in this manner, when a current to be detected (not shown) is applied to each conductor 1, output signals output in accordance with the amount of magnetic flux density detected by magnetoelectric conversion element Md and magnetoelectric conversion element Me are differentially calculated by a differential calculation unit (not shown), and the differential calculation value is output as an output signal from magnetic sensor 5C and output to the outside via substrate 4 and an output terminal (not shown). (At this time, since the amount of magnetic flux density detected by magnetoelectric conversion element Md and the amount of magnetic flux density detected by magnetoelectric conversion element Me are values ​​with different positive and negative signs, the amount of magnetic flux density detected by both is detected by differential calculation.) A similar cooling effect can be expected in current sensor 400 configured in this manner as well. DETAILED DESCRIPTION OF THE INVENTION Embodiment 5.

[0061] Figure 8 is a schematic diagram of a current sensor 500 relating to embodiment 5 of the present invention, where Figure 8(a) is an oblique view of the current sensor 500, Figure 8(b) is a front view of an exploded view of the current sensor 500, Figure 8(c) is a front view of the current sensor 500, Figure 8(d) is a cross-sectional view showing section CC in Figure 8(c), and Figure 8(e) is an oblique view showing the internal structure of the current sensor 500, showing only the conductor 1D and cooling plate 2 of the current sensor 500.

[0062] The current sensor 500 includes a conductor 1D having a slit 1d penetrating in the Y direction, bending twice at the slit 1d and extending in the Z direction, a magnetic sensor 5D having magnetoelectric conversion elements Mf and Mg and a differential calculation unit (not shown) that detects the magnetic flux generated when a current to be detected is applied to the conductor 1D, and a housing 8D having three insertion holes 8d into which the magnetic sensor 5D is inserted, and the magnetic sensor 5D is a magnetic detection device such as a SIP-type IC that outputs an output signal according to the amount of magnetic flux density detected by the magnetoelectric conversion elements Md and Me.

[0063] As shown in Figure 8, when the substrate 4 of the current sensor 500 is fixed to the housing 8D, the magnetic sensor 5D is arranged in the insertion hole 8d of the housing 8D in such a manner that the magnetoelectric conversion elements Mf and Mg face each other in the Z direction across the slit 1d, and their magnetic sensing direction is in the X+ direction.

[0064] In the current sensor 500 thus formed, when a current to be detected (not shown) is applied in the Z+ direction to the current application surface U, current application surface V, and current application surface W of the conductors 1 of the U, V, and W phases, output signals output in accordance with the amount of magnetic flux density detected by the magnetoelectric conversion elements Mf and Mg are differentially calculated by a differential calculation unit (not shown), and the differential calculation value is output as an output signal from the magnetic sensor 5D and transmitted to the outside via the substrate 4 and the output terminal 6. TIFF2025165843000002.tif13165The magnetic flux density amount detected is the sum of both.) A similar cooling effect can be expected in current sensor 500 configured in this way.

[0065] The current sensors according to the first to fourth embodiments of the present invention use means for detecting magnetic flux generated when a current to be detected is applied, and therefore, if the cooling plate 2 is made of a magnetic material, magnetic saturation occurs in the cooling plate 2. This affects the detection of the current to be detected, so when a means for detecting magnetic flux is used, it is desirable to form the cooling plate 2 from a non-magnetic material such as copper or aluminum.

[0066] Furthermore, up to this point we have explained a current sensor having a detection means for detecting the magnetic flux generated when a current to be detected is applied, but the present invention can also be applied to a current detection device having other detection means.

[0067] For example, in a shunt sensor that uses a shunt resistor to detect the voltage drop between any two points on a conductor to which the current to be detected is applied and detect the current value of the current to be detected, the conductor heats up when the current to be detected is applied, and the resistance value of the conductor fluctuates due to the heat generated, which deteriorates the detection accuracy, so there is a problem that the shunt sensor cannot be used when the current to be detected has a large current value.

[0068] However, by applying the present invention to a shunt sensor, it is possible to cool the heat generated by the application of the current to be detected, and therefore it is possible to use the shunt sensor even when the current to be detected has a large current value. The application of the present invention to a shunt sensor will be described below. DETAILED DESCRIPTION OF THE INVENTION Embodiment 5.

[0069] FIG. 9 is a schematic diagram of a shunt sensor 600 according to a fifth embodiment of the present invention. FIG. 9(a) is a perspective view of the shunt sensor 600, and FIG. 9(b) is an exploded perspective view of the shunt sensor 600. As shown in FIG.

[0070] 9, the shunt sensor 600 includes a rectangular conductor 1E formed of a conductor portion 1Ea and a conductor portion 1Eb having a resistance value different from that of the conductor portion 1Ea in a portion thereof, to which a current to be detected (not shown) is applied in the Z direction, a cooling plate 2C having two fastening portions 3, a voltage drop detection portion (not shown), a substrate 4A on which an output terminal 6A is mounted, a housing 8E formed of a housing 8Ea and a housing 8Eb, and two screws 7 which are tapping screws for assembling the housings 8Ea and 8Eb, and the conductor 1E extends in the Z direction, and the cooling plate 2C penetrates the inside of the housing 8Eb and is fixed to the housing 8Eb in an orientation extending in the X direction, with the two fastening portions 3 not overlapping the housing 8Eb. The board 4A has a voltage drop detection unit (not shown) connected to and fixed to two conductor portions 1Ea, the conductor 1E to which the board 4A is fixed is placed in a placement portion 8Ec of the housing 8Eb, the housing 8Ea is then assembled to the housing 8Eb from the Y+ direction to the Y- direction, and two screws 7 are passed through the screw through holes 8Ed of the housing 8Ea and screwed into the screw pilot holes 8Ee of the housing 8Eb to form the housing 8E, whereby the conductor 1E is fixed in a position where it penetrates the housing 8E, the board 4A is placed inside the housing 8E, and the output terminal 6A is fixed to the housing 8E in an arrangement in which an external connection portion (not shown) is exposed from a terminal window 8Ef of the housing 8Ea.

[0071] The voltage drop detection unit (not shown) is a detection unit that detects voltage drops using a general shunt resistor, and is connected to the conductor portion 1Ea on the Z+ direction side and the conductor portion 1Ea on the Z- direction side, respectively, and has a resistance value between them that is different from that of the conductor portion 1Eb. When a current to be detected (not shown) is applied in the Z+ direction to the current application surface S of the conductor 1E of the shunt sensor 600, the voltage drop between the conductors 1Ea is detected, and an output signal corresponding to the detected voltage drop value is output to the outside via the substrate 4A and the output terminal 6A. A similar cooling effect can be expected with the shunt sensor 600 formed in this way.

[0072] In addition, the shunt sensor 600 has one conductor 1E and one current detection phase, but it may be configured with three phases like the current sensor 100 related to embodiment 1 of the present invention, and just as examples of shape and arrangement changes to the conductor 1 and cooling plate 2 are shown for the current sensor 100, the shunt sensor 600 may also have similar shape and arrangement changes to the conductor 1E and cooling plate 2C.

[0073] Regarding the effects of the present invention, the results of a simulation using the current sensor 100 according to the first embodiment of the present invention will be shown below.

[0074] Figure 10 shows a current sensor 100 according to embodiment 1 of the present invention used in the simulation, where Figure 10(a) is an oblique view of the current sensor 100 used in the simulation, Figure 10(b) is a plan view of the current sensor 100 used in the simulation, and Figure 10(c) is a cross-sectional view showing section DD in Figure 10(b).

[0075] In this simulation, the ambient temperature was set to 105°C, and a DC current of 200 A (not shown) was applied as the detected current in the Z+ direction from the current application surface U, current application surface V, and current application surface W of each conductor 1 of the U, V, and W phases until the temperature reached equilibrium.

[0076] In this simulation, the conductor 1 of the current sensor 100 is made of copper, the cooling plate 2 is made of copper, the substrate 4 is made of glass epoxy resin, the screws 7 are made of iron, and the housing 8 is made of polyphenyl sulfide (PPS) resin. The package portion (not shown) of the magnetic sensor 5 in which the magnetoelectric conversion element M is sealed is made of thermosetting epoxy resin, and the connection portion (not shown) with the substrate 4 is made of copper alloy, and the five pin portions of the terminal 6 are made of copper alloy, and the pin fixing portion that fixes the five pins is made of polybutylene terephthalate (PBT) resin.

[0077] The main dimensions of the current sensor 100 used in this simulation are shown in Figure 10. The X-direction dimension W1 of the housing 8 is 115.0 mm, the Y-direction dimension H1 is 11.0 mm, and the Z-direction dimension D1 is 19.0 mm. The X-direction dimension W2 of the cooling plate 2 is 150.0 mm, the Y-direction dimension H2 is 1.5 mm, and the Z-direction dimension D2 is 13.0 mm. The X-direction dimension W3 of the U-phase conductor 1, the X-direction dimension W4 of the V-phase conductor 1, and the X-direction dimension W5 of the W-phase conductor 1 are 15.0 mm. The Y-direction dimension H3 of the U-phase, V-phase, and W-phase conductors 1 is 1.5 mm. The Z-direction dimension D3 of the U-phase, V-phase, and W-phase conductors 1 is 55.0 mm.

[0078] The current sensor 100 has an imaginary center line CL1 with dimensions W1 and W4, an imaginary center line CL2 with dimension W3, and an imaginary center line CL3 with dimension W5, and the dimension W6 between the center lines CL1 and CL2 is 35.0 mm, and the dimension W7 between the center lines CL1 and CL3 is 35.0 mm.

[0079] The distance dimension (not shown) from the Y-direction underside of the housing 8 to the Y-direction underside of the cooling plate 2 is 1.5 mm, and the distance dimension (not shown) from the Y+ direction upper surface of the cooling plate 2 to the Y-direction undersides of the U-phase, V-phase, and W-phase conductors 1 is 1.5 mm.

[0080] Assuming that the current sensor 100 is connected to the cooler by the fastening part 3, the simulation was performed by setting the cooling range to the range of dimension W8 from the end of the cooling plate 2 in the X-direction and the range of dimension W9 from the end of the cooling plate 2 in the X+ direction, and setting the bottom surface of the cooling plate 2 in the Y-direction within the cooling range to 100.0°C. The dimensions W8 and W9 are 13.0 mm, and in this simulation, detailed dimensions of each component other than the main dimensions shown above will be omitted.

[0081] A simulation was also performed assuming that the cooling plate 2 was made of the same polyphenyl sulfide resin as the housing 8 (the cooling plate 2 was made of the same material as the housing 8), i.e., that there was no cooling plate, and the cooling effect of the present invention was compared.

[0082] Figure 11 is a table showing the results of the simulation, showing the maximum temperature values ​​of conductor 1 for each of the U, V, and W phases for the simulation results when cooling plate 2 is set to copper and the simulation results when cooling plate 2 is set to polyphenyl sulfide (PPS) resin (assuming there is no cooling plate), as well as the temperature difference.

[0083] As shown in FIG. 11, when comparing the cooling plate 2 of the present invention, which is configured with copper, with the cooling plate 2 of polyphenyl sulfide resin, there is a cooling effect of approximately 60° C. in the U, V, and W phases.

[0084] Furthermore, the configuration of the present invention can be combined with the conventional method of cooling a conductor by connecting it to an inverter with a cooling function. By combining the configuration of the present invention with the conventional cooling method, it becomes possible to apply current values ​​that cannot be applied with conventional current sensors, which contributes to improving the driving performance of electric vehicles and hybrid vehicles. [Explanation of symbols]

[0085] 1 conductor 1A conductor 1B conductor 1C conductor 1D conductor 1E conductor 1a Notched part 1b Bend part 1Ca slit 1d slit 1Ea Conductor 1Eb conductor 2 Cooling plate 2A cooling plate 2B Cooling plate 2C cooling plate 2a Notched part 3 Fastening part 4 boards 4A board 5 Magnetic Sensor 5A magnetic sensor 5B Magnetic Sensor 5C magnetic sensor 5D Magnetic Sensor 6 Output terminals 6A output terminal 7 screws 8. Housing 8A housing 8B case 8C case 8D chassis 8E chassis 8Ea chassis 8Eb case 8Ec placement part 8Ed screw through holes 8Ee screw pilot hole 8Ef terminal window 9 PCB base 10 Cooler 11 Cooling enclosure 11a Flow path 12 Cooling terminal 12a Cooling fastener 13 volts 14 Heat transfer path 15 Magnetic core 15a void 15b Core Gap 16 Magnetic core 16a void 100 Current Sensor 101 Current Sensor 200 Current Sensor 300 Current Sensor 400 Current Sensor 500 Current Sensor 600 Current Sensor M magnetoelectric conversion element Ma magnetoelectric conversion element Mb magnetoelectric conversion element Mc magnetoelectric conversion element Me magnetoelectric conversion element Mf magnetoelectric conversion element Mg magnetoelectric conversion element

Claims

1. A current detection device that is connected to and fixed to a cooler, and in which heat generated by application of a current to be detected is cooled by the cooler, a rectangular primary conductor to which the current to be detected is applied; a detection unit having a detection means for detecting the target current; a cooling plate that transfers heat generated when the detection current is applied to the primary conductor and has a fastening portion for connecting to at least one of the coolers; a housing to which the primary conductor, the detection unit, and the cooling plate are fixed, the primary conductor extends through the interior of the housing and is fixed to the housing; The cooling plate is located on the underside of the extension direction of the primary conductor, extends in a direction perpendicular to the extension direction of the primary conductor, and is fixed to the housing in a position where the fastening portion does not overlap with the housing.

2. The detection means detects a magnetic flux generated when the current to be detected is applied to the primary conductor, the cooling plate is made of a non-magnetic material; the detection unit includes a magnetic sensor having at least one magnetoelectric conversion element that detects magnetic flux generated when the current to be detected is applied, and an analog circuit and an output terminal that output an output signal corresponding to the detected magnetic flux to an external device; 2. The current detection device according to claim 1, wherein the magnetic sensor is arranged so that the magnetoelectric conversion element is on the upper or lower surface side in the extension direction of the primary conductor in which the voltage is applied to the primary conductor.

3. the detecting means is means for detecting a voltage drop in the primary conductor when the current to be detected is applied to the primary conductor, 2. The current detection device according to claim 1, wherein the detection unit includes a voltage detector that detects a voltage drop value between any two points on the primary conductor.

4. The number of the magnetoelectric conversion element is one, 3. The current detection device according to claim 2, wherein the magnetic sensing axis direction of the magnetoelectric conversion element is the extension direction of the cooling plate.

5. The number of the magnetoelectric conversion elements is two, and the two magnetoelectric conversion elements are arranged side by side at a distance in the extension direction of the cooling plate on the upper surface side or the lower surface side in the extension direction of the primary conductor, 3. The current detection device according to claim 2, wherein the magnetic sensing axis direction of the magnetoelectric conversion element is perpendicular to the extending direction of the primary conductor and the extending direction of the cooling plate.

6. the primary conductor has a through slit; The number of the magnetoelectric conversion elements is two, The magnetic sensor is arranged such that the two magnetoelectric conversion elements are disposed on opposite sides of the through slit of the primary conductor, one on the upper surface side and one on the lower surface side in the extension direction of the primary conductor, and the through slit is sandwiched between the two magnetoelectric conversion elements, 3. The current detection device according to claim 2, wherein the magnetic sensing axis direction of the magnetoelectric conversion element is the extension direction of the cooling plate.

7. 7. The current detection device according to claim 6, wherein the primary conductor has a shape that is bent at least once at the through slit.

8. the detection unit has a first gap formed in a substantially C-shape and a magnetic core having a core gap, 5. The current detection device according to claim 4, wherein the magnetic core is arranged in such a manner that the primary conductor passes through the first gap portion, and the magnetic sensor is arranged so that the magnetoelectric conversion element is within the core gap.

9. the detection unit has a magnetic core having a second gap formed in a substantially U-shape, the magnetic core is disposed in such a position that the primary conductor passes through the second gap, 5. The current detection device according to claim 4, wherein the magnetic sensor is disposed so that the magnetoelectric conversion element is located in the second gap.

10. 4. The current detection device according to claim 3, wherein the primary conductor has different resistance values ​​between any two points where the voltage detector detects a voltage.

11. 2. The current detection device according to claim 1, wherein the thermal conductivity of the material forming the cooling plate is higher than the thermal conductivity of the material forming the housing.

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