WO2016035606A1 - Current sensor - Google Patents
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- WO2016035606A1 WO2016035606A1 PCT/JP2015/073807 JP2015073807W WO2016035606A1 WO 2016035606 A1 WO2016035606 A1 WO 2016035606A1 JP 2015073807 W JP2015073807 W JP 2015073807W WO 2016035606 A1 WO2016035606 A1 WO 2016035606A1
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- magnetic
- sensor
- primary conductor
- current
- magnetic sensor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
Definitions
- the present invention relates to a current sensor, and more particularly to a current sensor that measures the value of a current to be measured by detecting a magnetic field generated according to the current to be measured.
- JP 2010-2277 A Patent Document 1
- JP 2010-8050 A Patent Document 2
- JP 2013-11469 A Patent Document 3
- JP 2013-238580 A Patent Document 4
- JP 2013-228315 A Patent Document 5
- JP 2001-281270 A Patent Document 6
- the current sensor described in Patent Document 1 includes a bus bar, an insulating substrate, a Hall IC as a magnetic detection element, and a magnetic shield for each of the U phase, the V phase, and the W phase.
- the upper magnetic shield member and the lower magnetic shield member form an annular enclosure that annularly surrounds the bus bar, the insulating substrate, and the Hall IC, thereby magnetically shielding the external magnetic field.
- a gap is formed between the upper magnetic shield member and the lower magnetic shield member. The position in the height direction of the gap is the same as or near the position in the height direction of the bus bar, and the gap is located at a portion facing the side surface of the bus bar.
- the Hall IC is arranged above the central portion of the bus bar.
- the current sensor described in Patent Document 2 includes a nonmagnetic spacer in addition to the configuration of the current sensor described in Patent Document 1.
- the protrusions of the nonmagnetic spacer are engaged with the gaps of the magnetic shield body. Thereby, the space
- the current sensor described in Patent Document 3 includes a sensor substrate on which a magnetoresistive effect element is formed, a measured conductor through which a measured current flows, and a magnetic shield portion that surrounds the sensor substrate and the measured conductor. And have. Two gaps for suppressing magnetic saturation in the magnetic shield part are formed in the magnetic shield part, and the magnetic flux flowing in the magnetic shield part is released in the gap. An air gap is formed at a portion of the magnetic shield portion having a symmetrical structure. The height position of the air gap and the height position of the sensor substrate in the z direction are the same.
- the current sensor described in Patent Document 4 includes a bus bar that is a conductor through which a current to be measured flows, a Hall IC as a magnetosensitive element, and first and second magnets that form a pair that magnetically shields the Hall IC from an external magnetic field. Have a body. Both ends of the first and second magnetic bodies forming a pair are opposed to each other with a gap.
- the current sensor described in Patent Document 5 includes a bus bar, a main core, a sub core, and a magnetosensitive element.
- the main core has an annular shape (C-type) with a gap, and the bus bar passes therethrough.
- the sub-core is U-shaped (semi-annular) and its end face is located in the vicinity of the gap of the main core, is in non-contact with the main core and is in the same plane as the main core, and a part of the leakage flux of the main core flows.
- the magnetosensitive element is a Hall element, and exists in a position where the magnetic field generated by the residual magnetization of the main core and the magnetic field generated by the residual magnetization of the sub core are weakened in the gap of the main core.
- the current sensor described in Patent Document 6 includes a current sensor body, an inner magnetic shield case, and an outer magnetic shield case.
- the dividing direction of the inner magnetic shield case and the dividing direction of the outer magnetic shield case intersect each other.
- the inner magnetic shield case surrounds the current sensor body, and the outer magnetic shield case surrounds the inner magnetic shield case.
- the influence of the magnetic field generated by the residual magnetization of the magnetic shield body is smaller than that of the current sensors described in Patent Documents 1 and 2, but the main core, the sub-core, and the magnetosensitive element. Are required to be arranged at appropriate positions, high assembly accuracy is required, and the manufacture of the current sensor is difficult.
- the present invention has been made in view of the above problems, and an object of the present invention is to provide a current sensor that can be easily manufactured while reducing a measurement error due to a magnetic field generated by residual magnetization.
- a current sensor includes a primary conductor through which a current to be measured flows, at least one magnetic sensor for detecting the strength of a magnetic field generated by the current flowing through the primary conductor, and a direction in which the current flows. And a pair of magnetic members each having an L shape.
- the pair of magnetic members has a rectangular shape in which a gap is provided between the ends when viewed from the direction in which the current flows, and surrounds the primary conductor and the magnetic sensor.
- the primary conductor has a flat plate shape.
- the magnetic sensor can detect a magnetic field in a direction orthogonal to both the thickness direction of the primary conductor and the direction in which the current flows.
- the magnetic sensor is disposed at least one of the one side and the other side in the thickness direction of the primary conductor in the central portion in the width direction of the primary conductor.
- the current sensor includes a first magnetic sensor and a second magnetic sensor as magnetic sensors.
- the first magnetic sensor and the second magnetic sensor are positioned to face each other with the primary conductor interposed therebetween.
- the current sensor further includes a calculation unit that calculates the value of the current by calculating the detection value of the first magnetic sensor and the detection value of the second magnetic sensor. Regarding the strength of the magnetic field generated by the current flowing through the primary conductor, the phase of the detection value of the first magnetic sensor and the phase of the detection value of the second magnetic sensor are opposite in phase.
- the calculation unit is a subtractor or a differential amplifier.
- the current sensor further includes a calculation unit that calculates the value of the current by calculating the detection value of the first magnetic sensor and the detection value of the second magnetic sensor. Regarding the strength of the magnetic field generated by the current flowing through the primary conductor, the phase of the detection value of the first magnetic sensor and the phase of the detection value of the second magnetic sensor are in phase.
- the calculation unit is an adder or a summing amplifier.
- the current sensor further includes another pair of magnetic members each having an L shape when viewed from the direction in which the current flows.
- the other pair of magnetic members has a rectangular shape with a gap provided between the ends when viewed from the direction in which the current flows, and is spaced from the pair of magnetic members. Surrounding a pair of magnetic members. The gaps of the other pair of magnetic members are located outside the corners of each pair of magnetic members.
- FIG. 3 is a cross-sectional view of the current sensor of FIG. 2 as viewed from the direction of arrows III-III. It is a disassembled perspective view which shows the structure of the current sensor which concerns on Embodiment 1 of this invention. It is a perspective view which shows the external appearance of the circuit board of the current sensor which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the circuit structure of the current sensor which concerns on Embodiment 1 of this invention.
- FIG. 6 is a cross-sectional view showing a cross-sectional shape of a primary conductor according to Comparative Example 1.
- FIG. 3 is a cross-sectional view showing a cross-sectional shape of a primary conductor according to Example 1.
- FIG. 3 is a cross-sectional view schematically showing a magnetic field generated around a primary conductor according to Example 1.
- FIG. The distance from the front surface or the back surface of the primary conductor and the width direction of the primary conductor (X-axis direction) on the reference line located immediately above or directly below the central portion in the width direction of the primary conductor according to Comparative Example 1 and Example 1 ) Is a graph showing the relationship with the magnetic flux density.
- FIG. 17 is a cross-sectional view of the current sensor of FIG.
- the distance from the center position in the thickness direction of the primary conductor on the reference line located immediately above or directly below the center portion in the width direction of the primary conductor 5 is a graph showing the relationship between the magnetic flux density in the length direction (Y-axis direction) of the primary conductor.
- the distance from the center position in the thickness direction of the primary conductor on the reference line located immediately above or directly below the center portion in the width direction of the primary conductor 5 is a graph showing the relationship between the magnetic flux density in the thickness direction (Z-axis direction) of the primary conductor.
- FIG. 10 is a graph showing hysteresis rates of a current sensor 100 according to Example 2, a current sensor 200 according to Comparative Example 2, a current sensor 300 according to Comparative Example 3, and a current sensor according to Comparative Example 4. It is sectional drawing which shows the structure of the current sensor which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the structure of the current sensor which concerns on Embodiment 3 of this invention.
- the current sensor according to Embodiment 4 of the present invention it is a cross-sectional view showing a state where a printed board and a magnetic member are attached to a primary conductor.
- the current sensor according to Embodiment 4 of the present invention it is a cross-sectional view showing a state before the printed board and the magnetic member are attached to the primary conductor.
- FIG. 1 is a perspective view showing an appearance of a current sensor according to Embodiment 1 of the present invention.
- FIG. 2 is a side view of the current sensor of FIG. 1 viewed from the direction of arrow II.
- FIG. 3 is a cross-sectional view of the current sensor of FIG. 2 as viewed from the direction of arrows III-III.
- FIG. 4 is an exploded perspective view showing the configuration of the current sensor according to Embodiment 1 of the present invention.
- FIG. 5 is a perspective view showing an appearance of a circuit board of the current sensor according to the first embodiment of the present invention.
- FIG. 6 is a circuit diagram showing a circuit configuration of the current sensor according to Embodiment 1 of the present invention.
- the width direction of a primary conductor 110 which will be described later, is illustrated as an X-axis direction
- the length direction of the primary conductor 110 is defined as a Y-axis direction
- the thickness direction of the primary conductor 110 is illustrated as a Z-axis direction.
- the current sensor 100 detects the primary conductor 110 through which the current to be measured flows and the strength of the magnetic field generated by the current through the primary conductor 110.
- Two magnetic sensors are composed of a first magnetic sensor 120a and a second magnetic sensor 120b.
- the current sensor 100 includes two magnetic sensors.
- the present invention is not limited to this, and it is only necessary to include at least one magnetic sensor.
- the current sensor 100 includes a pair of magnetic members 170 each having an L shape when the primary conductor 110 is viewed from the direction in which current flows (Y-axis direction).
- the pair of magnetic members 170 includes a first magnetic member 171 and a second magnetic member 172.
- the pair of magnetic members 170 has a rectangular shape in which a gap 173 is provided between ends of each other when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction).
- the pair of magnetic members 170 includes a first circuit board 160a, a second circuit board 160b, and a portion sandwiched between the first circuit board 160a and the second circuit board 160b, which will be described later. It surrounds the second conductor 110 with a space.
- the relative positions of the primary conductor 110, the first circuit board 160a, the second circuit board 160b, and the pair of magnetic members 170 are maintained by a case (not shown).
- the case is preferably formed of an engineering plastic having high temperature resistance such as polyphenylene sulfide.
- each of the first circuit board 160a and the second circuit board 160b and the case are fastened with screws, it is preferably fastened with screws made of a non-magnetic material so as not to disturb the magnetic field.
- the primary conductor 110 has a flat plate shape.
- the primary conductor 110 has one penetrating portion that penetrates from the front surface to the back surface of the primary conductor 110.
- a circular through hole 110h is provided in a central portion in the width direction of the primary conductor 110 in a plan view. The current flows through the primary conductor 110 in the Y-axis direction.
- the primary conductor 110 is made of copper.
- the material of the primary conductor 110 is not limited to this, and may be a metal such as silver or aluminum or an alloy containing these metals.
- the primary conductor 110 may be subjected to a surface treatment.
- at least one plating layer made of a metal such as nickel, tin, silver, copper, or an alloy containing these metals may be provided on the surface of the primary conductor 110.
- the primary conductor 110 is formed by pressing a thin plate.
- the method of forming the primary conductor 110 is not limited to this, and the primary conductor 110 may be formed by a method such as cutting or casting.
- the first magnetic sensor 120a is mounted on the first printed circuit board 130a together with the first operational amplifier 140a and the first passive element 150a.
- the first magnetic sensor 120a is disposed at the center of the first printed circuit board 130a.
- the first magnetic sensor 120a, the first printed board 130a, the first operational amplifier 140a, and the first passive element 150a constitute a first circuit board 160a.
- the first printed circuit board 130a includes a substrate made of glass epoxy or alumina, and wiring formed by patterning a metal foil such as a copper foil on the substrate.
- the first circuit board 160a is configured with an arithmetic circuit that calculates a signal from the first magnetic sensor 120a.
- the second magnetic sensor 120b is mounted on the second printed circuit board 130b together with the second operational amplifier 140b and the second passive element 150b.
- the second magnetic sensor 120b is disposed at the center of the second printed circuit board 130b.
- the second magnetic sensor 120b, the second printed board 130b, the second operational amplifier 140b, and the second passive element 150b constitute a second circuit board 160b.
- Second printed circuit board 130b includes a substrate made of glass epoxy or alumina, and a wiring formed by patterning a metal foil such as a copper foil on the substrate.
- the second circuit board 160b is configured with an arithmetic circuit that calculates a signal from the second magnetic sensor 120b.
- the first circuit board 160a is placed on the surface of the primary conductor 110.
- the first magnetic sensor 120a is located immediately above the through hole 110h with the first printed board 130a sandwiched between the primary conductor 110.
- the second circuit board 160 b is disposed on the back surface of the primary conductor 110.
- the second magnetic sensor 120b is located directly below the through hole 110h with the second printed board 130b sandwiched between the primary conductor 110.
- first magnetic sensor 120a and the second magnetic sensor 120b are located on opposite sides of the primary conductor 110.
- the first magnetic sensor 120 a is disposed on one side (upper side) in the thickness direction (Z-axis direction) of the primary conductor 110 in the central portion in the width direction (X-axis direction) of the primary conductor 110.
- the second magnetic sensor 120b is disposed on the other side (lower side) in the thickness direction (Z-axis direction) of the primary conductor 110 at the center in the width direction (X-axis direction) of the primary conductor 110.
- the direction (magnetic direction) of the detection axis of each of the first magnetic sensor 120a and the second magnetic sensor 120b is the width direction (X-axis direction) of the primary conductor 110. That is, each of the first magnetic sensor 120a and the second magnetic sensor 120b is orthogonal to both the thickness direction (Z-axis direction) of the primary conductor 110 and the direction in which the current flows through the primary conductor 110 (Y-axis direction).
- the magnetic field in the direction (X-axis direction) can be detected.
- Each of the first magnetic sensor 120a and the second magnetic sensor 120b outputs a positive value when a magnetic field directed in one direction of the detection axis is detected, and is directed in a direction opposite to the one direction of the detection axis. It has an input / output characteristic that outputs a negative value when a magnetic field is detected.
- Each of the first magnetic sensor 120a and the second magnetic sensor 120b has a Wheatstone bridge type bridge circuit including four AMR (Anisotropic Magneto Resistance) elements.
- Each of the first magnetic sensor 120a and the second magnetic sensor 120b is replaced with an AMR element, and GMR (Giant Magneto Resistance), TMR (Tunnel Magneto Resistance), BMR (Balistic Magneto Resistance), CMR (Colossal Magneto Resistance). It may have a magnetoresistive element.
- each of the first magnetic sensor 120a and the second magnetic sensor 120b may have a half bridge circuit including two magnetoresistive elements.
- a magnetic sensor having a Hall element a magnetic sensor having an MI (Magneto Impedance) element using a magnetic impedance effect, a fluxgate type magnetic sensor, or the like is used.
- Magnetic elements such as a magnetoresistive element and a Hall element may be packaged with a resin, or may be potted with a silicone resin or an epoxy resin.
- Each AMR element of the first magnetic sensor 120a and the second magnetic sensor 120b has an odd function input / output characteristic by including a barber pole type electrode.
- each AMR element of the first magnetic sensor 120a and the second magnetic sensor 120b includes a barber pole type electrode, and is biased so that a current flows at a predetermined angle.
- the magnetization direction of the magnetoresistive film in the AMR element of the first magnetic sensor 120a and the magnetization direction of the magnetoresistive film in the AMR element of the second magnetic sensor 120b are the same direction. Thereby, the fall of the output accuracy by the influence of an external magnetic field can be made small.
- the current sensor 100 calculates the value of the current flowing through the primary conductor 110 by calculating the detection value of the first magnetic sensor 120a and the detection value of the second magnetic sensor 120b. Is provided.
- the calculation unit 190 is a differential amplifier. However, the calculation unit 190 may be a subtracter.
- each of the first magnetic member 171 and the second magnetic member 172 includes a first plate-like portion and a second plate-like portion orthogonal to the first plate-like portion. Have. The first plate-like portions of the first magnetic member 171 and the second magnetic member 172 and the primary conductor 110 are positioned in parallel to each other.
- Each of the two gaps 173 extends from one end of the pair of magnetic members 170 to the other end in the direction in which the current flows through the primary conductor 110 (Y-axis direction).
- Each of the two gaps 173 is located at a diagonal of a rectangular shape formed by the pair of magnetic members 170 when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction).
- the center position of the rectangular shape formed by the pair of magnetic members 170 and the position of the through hole 110h of the primary conductor 110 overlap. .
- Each of the first magnetic member 171 and the second magnetic member 172 is made of permalloy, but the material of each of the first magnetic member 171 and the second magnetic member 172 is not limited to permalloy, and is soft. Any magnetic material having high magnetic permeability and saturation magnetic flux density, such as iron steel, silicon steel, electromagnetic steel, nickel alloy, iron alloy, or ferrite, may be used.
- each of the first magnetic member 171 and the second magnetic member 172 is formed by pressing a thin plate.
- the formation method of each of the first magnetic member 171 and the second magnetic member 172 is not limited to this, and each of the first magnetic member 171 and the second magnetic member 172 is formed by a method such as cutting or casting. May be.
- FIG. 7 is a cross-sectional view showing the cross-sectional shape of the primary conductor according to Comparative Example 1.
- FIG. 8 is a cross-sectional view illustrating the cross-sectional shape of the primary conductor according to the first embodiment.
- the outer shape of the cross section of the primary conductor 110 was 30 mm wide and 2.5 mm thick.
- a through hole 110h having a diameter of 2 mm was provided at the center in the width direction of the primary conductor 110 according to the first embodiment.
- the reference line located immediately above or immediately below the central portion in the width direction of the primary conductor 110 The magnetic flux density distribution on 1 was calculated by simulation analysis.
- the pair of magnetic members 170 is not disposed.
- FIG. 9 is a cross-sectional view schematically showing a magnetic field generated around the primary conductor according to the first embodiment.
- FIG. 10 shows the distance from the front surface or the back surface of the primary conductor and the width direction of the primary conductor on the reference line located immediately above or directly below the central portion in the width direction of the primary conductor according to Comparative Example 1 and Example 1. It is a graph which shows the relationship with the magnetic flux density of (X-axis direction).
- the vertical axis represents the magnetic flux density (mT)
- the horizontal axis represents the distance (mm) from the front surface 110s or the back surface 110t of the primary conductor 110.
- the data of the primary conductor 110 according to the first embodiment is indicated by a solid line
- the data of the primary conductor 110 according to the comparative example 1 is indicated by a dotted line.
- the magnetic field 110e is generated by the current 10 flowing through the primary conductor 110 located on the left side of the through hole 110h according to the so-called right-handed screw law. Similarly, a magnetic field 110e is generated by the current 10 flowing through the primary conductor 110 located on the right side of the through hole 110h.
- LZ and the magnetic flux density RZ in the Z-axis direction due to the magnetic field 110e generated by the current 10 flowing through the primary conductor 110 located on the right side of the through hole 110h cancel each other.
- the magnetic flux density RX in the X-axis direction due to the generated magnetic field 110e is combined.
- LZ and the magnetic flux density RZ in the Z-axis direction due to the magnetic field 110e generated by the current 10 flowing through the primary conductor 110 located on the right side of the through hole 110h cancel each other.
- the magnetic flux density RX in the X-axis direction due to the generated magnetic field 110e is combined.
- the magnetic flux density in the X-axis direction on the reference line 1 located immediately above the central portion in the width direction of the primary conductor 110 according to Comparative Example 1 is the distance from the surface 110 s of the primary conductor 110. Decreases as the value increases.
- the magnetic flux density in the X-axis direction on the reference line 1 located immediately above the central portion in the width direction of the primary conductor 110 according to the first embodiment reaches a distance of 4 mm from the surface 110s of the primary conductor 110. The distance increases as the distance increases, and is substantially constant at a position of 4 mm to 10 mm from the surface 110 s of the primary conductor 110.
- the magnetic flux density in the X-axis direction on the reference line 1 located immediately above the central portion in the width direction of the primary conductor 110 according to Example 1 is the comparative example regardless of the distance from the surface 110s of the primary conductor 110. It is lower than the magnetic flux density in the X-axis direction on the reference line 1 located immediately above the central portion in the width direction of the primary conductor 110. This is because no current flows through the through hole 110h.
- the magnetic flux density in the X-axis direction on the reference line 1 located immediately below the center in the width direction of the primary conductor 110 according to Comparative Example 1 increases as the distance from the back surface 110t of the primary conductor 110 increases. It is falling.
- the magnetic flux density in the X-axis direction on the reference line 1 located immediately below the central portion in the width direction of the primary conductor 110 according to the first embodiment reaches a distance of 4 mm from the back surface 110t of the primary conductor 110. The distance increases as the distance increases, and is substantially constant at a position of 4 mm to 10 mm from the back surface 110 t of the primary conductor 110.
- the magnetic flux density in the X-axis direction on the reference line 1 located immediately below the central portion in the width direction of the primary conductor 110 according to Example 1 is the comparative example regardless of the distance from the back surface 110t of the primary conductor 110. It is lower than the magnetic flux density in the X-axis direction on the reference line 1 located immediately below the central portion in the width direction of the primary conductor 110. This is because no current flows through the through hole 110h.
- the first magnetic sensor 120a is disposed at a position immediately above the through hole 110h of the primary conductor 110, thereby providing the first magnetic sensor.
- the magnetic flux density acting on 120a can be reduced. Therefore, even when a large current flows through the primary conductor 110, it is possible to suppress the magnetic saturation of the magnetoresistive element of the first magnetic sensor 120a.
- the second magnetic sensor 120b by arranging the second magnetic sensor 120b at a position directly below the through hole 110h of the primary conductor 110, the magnetic flux density acting on the second magnetic sensor 120b can be reduced. Therefore, even when a large current flows through the primary conductor 110, it is possible to suppress magnetic saturation of the magnetoresistive element of the second magnetic sensor 120b.
- FIG. 11 is a graph showing the relationship between the magnetic flux density acting on the magnetoresistive element and the output voltage of the magnetoresistive element.
- the vertical axis represents the output voltage of the magnetoresistive element
- the horizontal axis represents the magnetic flux density acting on the magnetoresistive element.
- the output voltage of the magnetoresistive element increases in proportion to the increase of the magnetic flux density acting on the magnetoresistive element.
- the output voltage of the magnetoresistive element hardly increases even if the magnetic flux density acting on the magnetoresistive effect element increases.
- the first magnetism is reduced by reducing the magnetic flux density acting on the magnetoresistive element with a simple structure in which the through hole 110h is provided in the primary conductor 110 without using a complicated circuit.
- the sensor 120a and the second magnetic sensor 120b can be operated in the first region T 1.
- the input dynamic range of the current sensor 100 can be expanded, and a large current can be accurately measured by the current sensor 100.
- the first magnetic sensor 120a is disposed at a position immediately above the through hole 110h of the primary conductor 110
- the second magnetic sensor 120b is disposed at a position immediately below the through hole 110h of the primary conductor 110, thereby Since the magnetic flux density in the X-axis direction and the Z-axis direction acting on each of the magnetic sensor 120a and the second magnetic sensor 120b can be reduced, the strength of the magnetic field applied to each of the first magnetic sensor 120a and the second magnetic sensor 120b. It is possible to suppress the occurrence of variations. As a result, the current sensor 100 can stably measure the magnitude of the current to be measured.
- a position of 4 mm to 10 mm from the front surface 110s or the back surface 110t of the primary conductor 110 Is a robust region in which the magnetic flux density in the X-axis direction is substantially constant.
- the first magnetic sensor 120a is positioned directly above the through hole 110h with the first printed board 130a interposed between the primary conductor 110 and the first magnetic sensor 120a.
- the sensor 120a is located in the robust area. That is, the thickness of the first printed circuit board 130a is appropriately set so that the first magnetic sensor 120a is positioned in the robust region.
- the second magnetic sensor 120b is located directly below the through hole 110h with the second printed circuit board 130b sandwiched between the primary conductor 110 and the second magnetic sensor 120b. Is located in the robust region. That is, the thickness of the second printed circuit board 130b is appropriately set so that the second magnetic sensor 120b is located in the robust region.
- each of the first magnetic sensor 120a and the second magnetic sensor 120b By positioning each of the first magnetic sensor 120a and the second magnetic sensor 120b within the robust region, it is possible to stably cause variations in the strength of the magnetic field applied to each of the first magnetic sensor 120a and the second magnetic sensor 120b. Can be suppressed. As a result, the current sensor 100 can more stably measure the magnitude of the current to be measured.
- the primary conductor 110 is connected.
- the phase of the detection value of the first magnetic sensor 120a is opposite to the phase of the detection value of the second magnetic sensor 120b.
- the strength of the magnetic field detected by the first magnetic sensor 120a is a positive value
- the strength of the magnetic field detected by the second magnetic sensor 120b is a negative value.
- the detection value of the first magnetic sensor 120a and the detection value of the second magnetic sensor 120b are transmitted to the calculation unit 190.
- the calculation unit 190 subtracts the detection value of the second magnetic sensor 120b from the detection value of the first magnetic sensor 120a. As a result, the absolute value of the detection value of the first magnetic sensor 120a and the absolute value of the detection value of the second magnetic sensor 120b are added. From this addition result, the value of the current flowing through the primary conductor 110 is calculated.
- the primary conductor 110, the first printed board 130a, and the second printed board 130b are located between the first magnetic sensor 120a and the second magnetic sensor 120b.
- the external magnetic field source cannot be physically located between the first magnetic sensor 120a and the second magnetic sensor 120b.
- the direction of the magnetic field component in the direction of the detection axis of the magnetic field applied to the first magnetic sensor 120a from the external magnetic field source and the detection axis of the magnetic field applied to the second magnetic sensor 120b from the external magnetic field source is the same direction. Therefore, if the strength of the external magnetic field detected by the first magnetic sensor 120a is a positive value, the strength of the external magnetic field detected by the second magnetic sensor 120b is also a positive value.
- the calculation unit 190 subtracts the detection value of the second magnetic sensor 120b from the detection value of the first magnetic sensor 120a, thereby detecting the absolute value of the detection value of the first magnetic sensor 120a and the detection of the second magnetic sensor 120b.
- the absolute value of the value is subtracted. Thereby, the magnetic field from the external magnetic field source is hardly detected. That is, the influence of the external magnetic field is reduced.
- the directions of the detection axes with positive detection values may be opposite to each other (opposite 180 °).
- the strength of the external magnetic field detected by the first magnetic sensor 120a is a positive value
- the strength of the external magnetic field detected by the second magnetic sensor 120b is a negative value.
- the phase of the detection value of the first magnetic sensor 120a and the phase of the detection value of the second magnetic sensor 120b are in phase.
- an adder or an addition amplifier is used as the calculation unit 190 instead of the differential amplifier.
- the detected value of the first magnetic sensor 120a and the detected value of the second magnetic sensor 120b are added by an adder or an adding amplifier, thereby obtaining the absolute value of the detected value of the first magnetic sensor 120a.
- the absolute value of the detection value of the second magnetic sensor 120b is subtracted. Thereby, the magnetic field from the external magnetic field source is hardly detected. That is, the influence of the external magnetic field is reduced.
- the strength of the magnetic field generated by the current flowing through the primary conductor 110 is obtained by adding the detection value of the first magnetic sensor 120a and the detection value of the second magnetic sensor 120b by an adder or an addition amplifier.
- the absolute value of the detection value of the first magnetic sensor 120a and the absolute value of the detection value of the second magnetic sensor 120b are added. From this addition result, the value of the current flowing through the primary conductor 110 is calculated.
- an adder or an addition amplifier may be used as the calculation unit in place of the differential amplifier while the input / output characteristics of the first magnetic sensor 120a and the second magnetic sensor 120b have opposite polarities.
- each of the first magnetic sensor 120 a and the second magnetic sensor 120 b is surrounded by a pair of magnetic members 170.
- the external magnetic field that is an error factor can be suppressed from reaching each of the first magnetic sensor 120a and the second magnetic sensor 120b.
- each of the first magnetic sensor 120a and the second magnetic sensor 120b can be prevented from detecting an unnecessary external magnetic field. That is, the pair of magnetic members 170 functions as a magnetic shield.
- FIG. 12 is a perspective view showing an appearance of the current sensor according to Comparative Example 2.
- FIG. FIG. 13 is a side view of the current sensor of FIG. 12 as viewed from the direction of the arrow XIII.
- FIG. 14 is a cross-sectional view of the current sensor of FIG. 13 as viewed from the direction of arrows XIV-XIV.
- the current sensor 200 includes a pair of magnetic members 270 each having a U-shape when the primary conductor 110 is viewed from the direction in which current flows (Y-axis direction). Is provided.
- the pair of magnetic members 270 includes a first magnetic member 271 and a second magnetic member 272.
- the pair of magnetic members 270 has a rectangular shape in which a gap 273 is provided between the ends when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction).
- the pair of magnetic members 270 includes the first circuit board 160a, the second circuit board 160b, and the portion of the primary conductor 110 sandwiched between the first circuit board 160a and the second circuit board 160b. Is surrounded by a space.
- Each of the first magnetic member 271 and the second magnetic member 272 is a first plate-like portion and a second plate-like portion and a third plate-like shape that are orthogonal to the first plate-like portion and face each other. Part. The first plate-like portions of the first magnetic member 271 and the second magnetic member 272 and the primary conductor 110 are positioned in parallel to each other.
- Each of the two air gaps 273 extends from one end of the pair of magnetic members 270 to the other end in the direction in which the current flows through the primary conductor 110 (Y-axis direction).
- Each of the two gaps 273 is located at the center in the Z-axis direction on both sides of the rectangular shape formed by the pair of magnetic members 270 when viewed from the direction (Y-axis direction) in which the current flowing through the primary conductor 110 flows. is doing.
- the center position of the rectangular shape formed by the pair of magnetic members 270 and the position of the through hole 110h of the primary conductor 110 overlap each other when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). .
- FIG. 15 is a perspective view showing an appearance of a current sensor according to Comparative Example 3.
- FIG. 16 is a plan view of the current sensor of FIG. 15 viewed from the direction of the arrow XVI.
- FIG. 17 is a cross-sectional view of the current sensor of FIG. 16 viewed from the direction of the arrow XVII-XVII.
- the current sensor 300 has a pair of magnetic members 370 each having a U shape when the primary conductor 110 is viewed from the direction in which the current flows (Y-axis direction). Is provided.
- the pair of magnetic members 370 includes a first magnetic member 371 and a second magnetic member 372.
- the pair of magnetic members 370 has a rectangular shape in which a gap 373 is provided between the ends when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). Surrounding the conductor 110 and the two magnetic sensors.
- the pair of magnetic members 370 includes a first circuit board 160a, a second circuit board 160b, and a portion of the primary conductor 110 sandwiched between the first circuit board 160a and the second circuit board 160b. Is surrounded by a space.
- Each of the first magnetic member 371 and the second magnetic member 372 has a first plate-like portion and a second plate-like portion and a third plate-like shape that are orthogonal to the first plate-like portion and face each other. Part. The first plate-like portions of the first magnetic member 371 and the second magnetic member 372 and the primary conductor 110 are positioned in parallel to each other.
- Each of the two gaps 373 extends from one end of the pair of magnetic members 370 to the other end in the direction in which the current flows through the primary conductor 110 (Y-axis direction).
- Each of the two air gaps 373 is the center in the X-axis direction of each of the upper and lower sides of the rectangular shape formed by the pair of magnetic members 370 when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction).
- the size of the gaps 173, 273, and 373 was 1 mm.
- the size of the gaps 173, 273, 373 is the shortest distance between the first magnetic members 171, 271, 371 and the second magnetic members 172, 272, 372.
- the outer shape of the pair of magnetic members 170, 270, and 370 was 25.0 mm in length, 23.0 mm in width, and 20.0 mm in height.
- the plate thickness of each of the first magnetic members 171, 271 and 371 and the second magnetic members 172, 272 and 372 was 0.5 mm.
- the material of each of the first magnetic members 171, 271, 371 and the second magnetic members 172, 272, 372 was 42 alloy (42Ni).
- the outer dimensions of the primary conductor 110 were 80.0 mm in length, 13.0 mm in width, and 1.5 mm in height.
- the material of the primary conductor 110 was oxygen-free copper (C1020).
- FIG. 18 is a schematic diagram showing a state in which a pair of magnetic shields are uniformly magnetized. As shown in FIG. 18, when a current flows through the primary conductor 110 from the front side of the drawing to the back side of the drawing, the pair of magnetic members 170, 270, and 370 are paired with the pair of magnetic members 170, 270. , 370 is magnetized in the direction indicated by arrow 2 so as to circulate clockwise.
- FIG. 19 is a diagram showing a reference line and a center point in the Z-axis direction in the simulation analysis. As shown in FIG. 19, the magnetic flux density distribution on the reference line 1 located immediately above or directly below the central portion in the width direction of the primary conductor 110 was calculated by simulation analysis. The center position O in the thickness direction of the primary conductor 110 was set as the origin in the Z-axis direction.
- FIG. 20 shows the center of the primary conductor in the thickness direction on the reference line located immediately above or directly below the central portion in the width direction of the primary conductor in the current sensors according to Example 2, Comparative Example 2 and Comparative Example 3. It is a graph which shows the relationship between the distance from a position, and the magnetic flux density of the width direction (X-axis direction) of a primary conductor.
- FIG. 21 shows the center in the thickness direction of the primary conductor on the reference line located immediately above or directly below the center portion in the width direction of the primary conductor in the current sensors according to Example 2, Comparative Example 2 and Comparative Example 3. It is a graph which shows the relationship between the distance from a position, and the magnetic flux density of the length direction (Y-axis direction) of a primary conductor.
- FIG. 22 shows the center in the thickness direction of the primary conductor on the reference line located immediately above or directly below the central portion in the width direction of the primary conductor in the current sensors according to Example 2, Comparative Example 2 and Comparative Example 3. It is a graph which shows the relationship between the distance from a position, and the magnetic flux density of the thickness direction (Z-axis direction) of a primary conductor.
- the vertical axis represents the normalized magnetic flux density
- the horizontal axis represents the distance (mm) in the Z-axis direction from the center position O in the thickness direction of the primary conductor 110.
- the data of the current sensor 100 according to the second embodiment is indicated by a solid line
- the data of the current sensor 200 according to the comparative example 2 is indicated by a dotted line
- the data of the current sensor 300 according to the comparative example 3 is indicated by a one-dot chain line. Show.
- the arrangement positions 121 of the AMR elements of the first magnetic sensor 120a and the second magnetic sensor 120b are shown.
- each of the current sensor 200 according to the comparative example 2 and the current sensor 300 according to the comparative example 3 includes the first magnetic sensor 120 a and the second magnetic sensor 120 b at the arrangement position 121 of the AMR element.
- the normalized magnetic flux density Bx in the detection axis direction (X-axis direction) was about 0.3 to 0.5 in absolute value.
- the normalized magnetic flux density Bx in the detection axis direction (X-axis direction) of each of the first magnetic sensor 120a and the second magnetic sensor 120b is 0 at the AMR element arrangement position 121. .1 or less, which is smaller than the current sensor 200 according to Comparative Example 2 and the current sensor 300 according to Comparative Example 3.
- each of the current sensor 100 according to the second embodiment, the current sensor 200 according to the second comparative example, and the current sensor 300 according to the third comparative example is arranged in the Y-axis direction at the arrangement position 121 of the AMR element.
- Each of the normalized magnetic flux density By and the normalized magnetic flux density Bz in the Z-axis direction was substantially 0, and no difference was recognized.
- FIG. 23 is a graph showing a relationship between an input current value and a sensor output voltage in the current sensor according to the second embodiment.
- FIG. 24 is a graph showing an enlarged view of the vicinity 3 of the input current value in FIG.
- FIG. 25 is a graph showing the relationship between the input current value and the sensor output voltage in the current sensor according to Comparative Example 2.
- FIG. 26 is an enlarged graph showing the vicinity 3 of the input current value 0A in FIG.
- FIG. 27 is a graph showing the relationship between the input current value and the sensor output voltage in the current sensor according to Comparative Example 3.
- FIG. 28 is an enlarged graph showing the vicinity 3 of the input current value 0A in FIG. 23 to 28, the vertical axis represents the sensor output voltage (V), and the horizontal axis represents the input current (A).
- the current sensor 200 according to Comparative Example 2 and the current sensor 300 according to Comparative Example 3 each have an input current value.
- the sensor output voltage greatly deviated in the vicinity 3 of 0A.
- the current sensor 100 according to Example 2 when the input current flowing through the primary conductor 110 was swept positively and negatively, no deviation in sensor output voltage was observed in the vicinity 3 of the input current value of 0A.
- FIG. 29 is a graph showing hysteresis rates of the current sensor 100 according to the second embodiment, the current sensor 200 according to the second comparative example, the current sensor 300 according to the third comparative example, and the current sensor according to the fourth comparative example.
- the vertical axis represents the hysteresis rate (% FS) and the horizontal axis represents the sample name.
- the current sensor according to Comparative Example 4 differs from the current sensor according to Example 1 only in that a pair of magnetic members is not provided.
- the hysteresis rate is a 100-minute ratio of the difference in sensor output voltage when the input current value is 0 A to the sensor output voltage when the input current value is ⁇ 300 A.
- each of the current sensor 200 according to the comparative example 2 and the current sensor 300 according to the comparative example 3 has a hysteresis rate of 1.8% or more, whereas the current according to the second example.
- the hysteresis rate was reduced to 0.2%, which was substantially the same as the hysteresis rate of 0.1% of the current sensor according to Comparative Example 4 in which the pair of magnetic members were not provided.
- each of the two air gaps 173 is 1 as viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction).
- the first magnetic sensor 120a and the second magnetic sensor 120b are positioned in the robust region, high accuracy is not required for the assembly of the current sensor 100.
- the sensor 100 can be easily manufactured.
- the current sensor 400 according to the second embodiment is different from the current sensor according to the first embodiment only in that it further includes another pair of magnetic members, and thus the description of the other configurations will not be repeated.
- FIG. 30 is a cross-sectional view showing a configuration of a current sensor according to Embodiment 2 of the present invention. 30 is a cross-sectional view of the current sensor as viewed from the same direction as in FIG.
- the current sensor 400 includes another pair of magnetic elements each having an L shape when the primary conductor 110 is viewed from the direction in which the current flows (Y-axis direction).
- a body member 470 is further provided.
- the other pair of magnetic members 470 is composed of a third magnetic member 471 and a fourth magnetic member 472.
- the other pair of magnetic members 470 has a rectangular shape in which a gap 473 is provided between the ends when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction),
- the pair of magnetic members 170 is surrounded by a distance from the pair of magnetic members 170.
- the gaps 473 of the other pair of magnetic members 470 are located outside the corners 171r and 172r of the pair of magnetic members 170, respectively.
- Each of the third magnetic member 471 and the fourth magnetic member 472 has a third plate-like portion and a fourth plate-like portion orthogonal to the third plate-like portion.
- the third plate-like portion of each of the third magnetic member 471 and the fourth magnetic member 472 and the primary conductor 110 are positioned in parallel to each other.
- the third plate-like portion of the third magnetic member 471 and the first plate-like portion of the second magnetic member 172 are located in parallel with a distance from each other.
- the third plate-like portion of the fourth magnetic body member 472 and each first plate-like portion of the first magnetic body member 171 are positioned in parallel with an interval therebetween.
- the fourth plate-like portion of the third magnetic member 471 and the second plate-like portion of the first magnetic member 171 are located in parallel with a distance from each other.
- the fourth plate-like portion of the fourth magnetic body member 472 and each second plate-like portion of the second magnetic body member 172 are positioned in parallel with a space between each other.
- Each of the two gaps 473 extends from one end of the other pair of magnetic members 470 to the other end in the direction in which the current flows through the primary conductor 110 (Y-axis direction).
- Each of the two gaps 473 is located at a diagonal of a rectangular shape formed by the other pair of magnetic members 470 when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction).
- the center position of the rectangular shape formed by the other pair of magnetic members 470 overlaps the position of the through hole 110h of the primary conductor 110. ing.
- Each of the third magnetic member 471 and the fourth magnetic member 472 is made of permalloy, but the material of each of the third magnetic member 471 and the fourth magnetic member 472 is not limited to permalloy, and is soft. Any magnetic material having high magnetic permeability and saturation magnetic flux density, such as iron steel, silicon steel, electromagnetic steel, nickel alloy, iron alloy, or ferrite, may be used.
- each of the third magnetic member 471 and the fourth magnetic member 472 is formed by pressing a thin plate.
- the formation method of each of the third magnetic member 471 and the fourth magnetic member 472 is not limited to this, and each of the third magnetic member 471 and the fourth magnetic member 472 is formed by a method such as cutting or casting. May be.
- each of the first magnetic sensor 120a and the second magnetic sensor 120b includes a pair of magnetic members 170 and another pair of magnetic members 470. Therefore, it is possible to further suppress the external magnetic field, which is an error factor, from reaching each of the first magnetic sensor 120a and the second magnetic sensor 120b. As a result, each of the first magnetic sensor 120a and the second magnetic sensor 120b can be prevented from detecting an unnecessary external magnetic field. That is, each of the pair of magnetic members 170 and the other pair of magnetic members 470 functions as a magnetic shield.
- the gaps 473 of the other pair of magnetic members 470 are positioned outside the corners 171r and 172r of the pair of magnetic members 170, so that the first magnetic sensor 120a and the second magnetic member 120a.
- the sensor 120b can be completely surrounded by a pair of magnetic members 170 and another pair of magnetic members 470. As a result, each of the first magnetic sensor 120a and the second magnetic sensor 120b can be prevented from detecting an unnecessary external magnetic field.
- each of the two gaps 173 has a rectangular shape formed by the pair of magnetic members 170 when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). By being positioned diagonally, measurement errors due to the magnetic field generated by the residual magnetization of the pair of magnetic members 170 can be reduced.
- Embodiment 3 of the present invention a current sensor according to Embodiment 3 of the present invention will be described.
- the current sensor 500 according to the third embodiment is different from the current sensor according to the second embodiment only in that two magnetic sensors are mounted on one printed circuit board, and thus the description of the other configurations will not be repeated.
- FIG. 31 is a cross-sectional view showing a configuration of a current sensor according to Embodiment 3 of the present invention.
- FIG. 31 shows in the cross-sectional view which looked at the current sensor from the same direction as FIG.
- the printed circuit board 530c is held in a state where the primary conductor 110 is inserted into the through hole 530h. That is, the printed circuit board 530 c is positioned perpendicular to the primary conductor 110.
- the first magnetic sensor 120a and the second magnetic sensor 120b are mounted on a printed circuit board 530c together with a differential amplifier and a passive element.
- the differential amplifier and the passive element are not shown.
- the differential amplifier and the passive element may be mounted on a printed board different from the printed board 530c on which the first magnetic sensor 120a and the second magnetic sensor 120b are mounted.
- the first magnetic sensor 120a and the second magnetic sensor 120b are located on opposite sides of the through hole 530h. Each of the first magnetic sensor 120a and the second magnetic sensor 120b is located at an interval from the through hole 530h.
- the first magnetic sensor 120a is positioned directly above the through hole 530h, and the second printed circuit board 130b is positioned directly below the through hole 530h. . That is, the first magnetic sensor 120a and the second magnetic sensor 120b are located on opposite sides of the primary conductor 110.
- each of the first magnetic sensor 120a and the second magnetic sensor 120b is located in the robust region. That is, the interval between each of the first magnetic sensor 120a and the second magnetic sensor 120b and the through hole 530h is appropriately set so that the first magnetic sensor 120a and the second magnetic sensor 120b are positioned in the robust region.
- the direction (magnetic direction) of the detection axis of each of the first magnetic sensor 120a and the second magnetic sensor 120b is the width direction (X-axis direction) of the primary conductor 110.
- the magnetic flux density in the X-axis direction, the Y-axis direction, and the Z-axis direction acting on each of the first magnetic sensor 120a and the second magnetic sensor 120b can be reduced. Variations in the strength of the magnetic field applied to the first magnetic sensor 120a and the second magnetic sensor 120b can be suppressed. As a result, the current sensor 500 can stably measure the magnitude of the current to be measured.
- each of the two gaps 173 has a rectangular shape formed by the pair of magnetic members 170 when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). By being positioned diagonally, measurement errors due to the magnetic field generated by the residual magnetization of the pair of magnetic members 170 can be reduced.
- the gaps 473 of the other pair of magnetic members 470 are positioned outside the corners 171r and 172r of the pair of magnetic members 170, so that the first magnetic sensor 120a and the second magnetic member 120a.
- the sensor 120b can be completely surrounded by a pair of magnetic members 170 and another pair of magnetic members 470. As a result, each of the first magnetic sensor 120a and the second magnetic sensor 120b can be prevented from detecting an unnecessary external magnetic field.
- the current sensor 600 according to the fourth embodiment differs from the current sensor according to the third embodiment only in that the printed circuit board and the magnetic member are configured to be detachable from the primary conductor. Will not repeat the description.
- FIG. 32 is a cross-sectional view showing a state where a printed circuit board and a magnetic member are attached to a primary conductor in a current sensor according to Embodiment 4 of the present invention.
- FIG. 33 is a cross-sectional view illustrating a state before the printed circuit board and the magnetic member are attached to the primary conductor in the current sensor according to the fourth embodiment of the present invention. 32 and 33 are shown in a cross-sectional view of the current sensor as viewed from the same direction as in FIG.
- the first magnetic member 171 of the pair of magnetic members 170 and the other pair of magnetic members 470 As shown in FIGS. 31 and 32, in the current sensor 600 according to the fourth embodiment of the present invention, the first magnetic member 171 of the pair of magnetic members 170 and the other pair of magnetic members 470.
- the third magnetic body member 471 and the printed board 630c are joined together by a first joining member 681 made of resin or adhesive, and are integrated.
- the second magnetic member 172 of the pair of magnetic members 170 and the fourth magnetic member 472 of the other pair of magnetic members 470 are made of a resin or an adhesive. They are joined together by 682 and integrated.
- the peripheral surface of the printed circuit board 630c and the inner surface of the first magnetic member 171 are joined to each other by the first joining member 681.
- the outer surface of the second plate-like portion of the first magnetic member 171 and the inner surface of the fourth plate-like portion of the third magnetic member 471 facing each other are joined to each other by the first joining member 681.
- the outer surface of the second plate-like portion of the second magnetic member 172 and the inner surface of the fourth plate-like portion of the fourth magnetic member 472 facing each other are joined to each other by the second joining member 682.
- a through groove 630h is provided from the end surface side of the peripheral surface of the printed circuit board 630c that is not surrounded by the first magnetic member 171 and the third magnetic member 471 to the opposite end surface.
- a gap is provided between the printed board 630c and the third plate-like portion of the third magnetic member 471 so that the first plate-like portion of the second magnetic member 172 can be inserted.
- the primary conductor 110 is inserted into the through groove 630h of the printed board 630c.
- the printed circuit board 630 c, the first magnetic member 171, and the third magnetic member 471 are moved closer to the primary conductor 110 in the direction indicated by the arrow 61.
- the first plate-like portion of the second magnetic member 172 is inserted in the direction indicated by the arrow 62 so that the first plate-like portion of the second magnetic member 172 is inserted into the gap between the printed circuit board 630c and the third plate-like portion of the third magnetic member 471.
- the second magnetic member 172 and the fourth magnetic member 472 are brought closer to the primary conductor 110.
- the printed circuit board 630c and the magnetic member are attached to the primary conductor 110, the printed circuit board 630c is held with the primary conductor 110 inserted in the through groove 630h. . That is, the printed circuit board 630 c is positioned perpendicular to the primary conductor 110.
- each of the two gaps 173 and the two gaps 473 is filled with at least one of the first joining member 681 and the second joining member 682.
- the printed circuit board 630c and the magnetic member are configured to be detachable from the primary conductor 110, so that the assembly and disassembly of the current sensor 600 is easy.
- each of the two gaps 173 has a rectangular shape formed by a pair of magnetic members 170 when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). By being positioned diagonally, measurement errors due to a magnetic field generated by the residual magnetization of the pair of magnetic members 170 can be reduced.
- the gaps 473 of the other pair of magnetic members 470 are positioned outside the corners 171r and 172r of the pair of magnetic members 170, so that the first magnetic sensor 120a and the second magnetic member 120a.
- the sensor 120b can be completely surrounded by a pair of magnetic members 170 and another pair of magnetic members 470. As a result, each of the first magnetic sensor 120a and the second magnetic sensor 120b can be prevented from detecting an unnecessary external magnetic field.
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Abstract
This current sensor is provided with: a primary conductor (110) in which a current to be measured flows; at least one magnetic sensor (120a, 120b) that detects the strength of a magnetic field generated by means of the current flowing in the primary conductor (110); and a pair of magnetic material members (170), each of which has an L-shape when viewed from the direction in which the current flows. The pair of magnetic material members (170) form a rectangular shape when viewed from the direction in which the current flows, said rectangular shape being provided with gaps (173) between the end portions of respective magnetic material members, and surround the primary conductor (110) and the magnetic sensors (120a, 120b).
Description
本発明は、電流センサに関し、特に、測定対象の電流に応じて発生する磁界を検出することで測定対象の電流の値を測定する電流センサに関する。
The present invention relates to a current sensor, and more particularly to a current sensor that measures the value of a current to be measured by detecting a magnetic field generated according to the current to be measured.
電流センサの構成を開示した先行文献として、特開2010-2277号公報(特許文献1)、特開2010-8050号公報(特許文献2)、特開2013-11469号公報(特許文献3)、特開2013-238580号公報(特許文献4)、特開2013-228315号公報(特許文献5)、および、特開2001-281270号公報(特許文献6)がある。
As prior documents disclosing the configuration of the current sensor, JP 2010-2277 A (Patent Document 1), JP 2010-8050 A (Patent Document 2), JP 2013-11469 A (Patent Document 3), JP 2013-238580 A (Patent Document 4), JP 2013-228315 A (Patent Document 5), and JP 2001-281270 A (Patent Document 6).
特許文献1に記載された電流センサは、U相、V相およびW相の各々について、バスバーと、絶縁基板と、磁気検出素子としてのホールICと、磁気シールド体とを備える。磁気シールド体は、上側磁気シールド部材および下側磁気シールド部材によって、バスバーと絶縁基板とホールICとを環状に囲む環状囲み部を構成することで、外部磁界から磁気遮蔽するものである。上側磁気シールド部材および下側磁気シールド部材の間に空隙が形成されている。空隙の高さ方向の位置は、バスバーの高さ方向の位置と同じまたは近傍であり、バスバーの側面と対向する部分に空隙が位置している。ホールICはバスバーの中央部の上方に配置されている。
The current sensor described in Patent Document 1 includes a bus bar, an insulating substrate, a Hall IC as a magnetic detection element, and a magnetic shield for each of the U phase, the V phase, and the W phase. In the magnetic shield body, the upper magnetic shield member and the lower magnetic shield member form an annular enclosure that annularly surrounds the bus bar, the insulating substrate, and the Hall IC, thereby magnetically shielding the external magnetic field. A gap is formed between the upper magnetic shield member and the lower magnetic shield member. The position in the height direction of the gap is the same as or near the position in the height direction of the bus bar, and the gap is located at a portion facing the side surface of the bus bar. The Hall IC is arranged above the central portion of the bus bar.
特許文献2に記載された電流センサは、特許文献1に記載された電流センサの構成に加えて、非磁性スペーサを備える。磁気シールド体の空隙に非磁性スペーサの凸条が係合している。これにより、空隙スリットの間隔は凸条にて一定に規制されている。
The current sensor described in Patent Document 2 includes a nonmagnetic spacer in addition to the configuration of the current sensor described in Patent Document 1. The protrusions of the nonmagnetic spacer are engaged with the gaps of the magnetic shield body. Thereby, the space | interval of a space | gap slit is controlled uniformly by the protruding item | line.
特許文献3に記載された電流センサは、形成面に磁気抵抗効果素子が形成されているセンサ基板と、被測定電流が流れる被測定導体と、センサ基板および被測定導体の周囲を囲む磁気シールド部とを有する。磁気シールド部には、磁気シールド部内の磁気飽和を抑制するための2つの空隙が形成されており、磁気シールド部内を流れる磁束は空隙にて放出される。磁気シールド部における対称な構造を成す部位に、空隙が形成されている。z方向における、空隙の高さ位置と、センサ基板の高さ位置とが同一である。
The current sensor described in Patent Document 3 includes a sensor substrate on which a magnetoresistive effect element is formed, a measured conductor through which a measured current flows, and a magnetic shield portion that surrounds the sensor substrate and the measured conductor. And have. Two gaps for suppressing magnetic saturation in the magnetic shield part are formed in the magnetic shield part, and the magnetic flux flowing in the magnetic shield part is released in the gap. An air gap is formed at a portion of the magnetic shield portion having a symmetrical structure. The height position of the air gap and the height position of the sensor substrate in the z direction are the same.
特許文献4に記載された電流センサは、被測定電流が流れる導体であるバスバーと、感磁素子としてのホールICと、ホールICを外部磁界から磁気遮蔽する対をなす第1および第2の磁性体とを有している。対をなす第1および第2の磁性体の両端縁は空隙を隔てて対向している。
The current sensor described in Patent Document 4 includes a bus bar that is a conductor through which a current to be measured flows, a Hall IC as a magnetosensitive element, and first and second magnets that form a pair that magnetically shields the Hall IC from an external magnetic field. Have a body. Both ends of the first and second magnetic bodies forming a pair are opposed to each other with a gap.
特許文献5に記載された電流センサは、バスバーと、メインコアと、サブコアと、感磁素子とを備える。メインコアは、ギャップを有する環状(C型)であり、バスバーが貫通する。サブコアは、U型(半環状)であって端面がメインコアのギャップの近傍に位置し、メインコアと非接触でメインコアと同一平面内にあり、メインコアの漏洩磁束の一部が流れる。感磁素子は、ホール素子であり、メインコアのギャップ内であってメインコアの残留磁化により発生する磁界とサブコアの残留磁化により発生する磁界とが弱め合う位置に存在する。
The current sensor described in Patent Document 5 includes a bus bar, a main core, a sub core, and a magnetosensitive element. The main core has an annular shape (C-type) with a gap, and the bus bar passes therethrough. The sub-core is U-shaped (semi-annular) and its end face is located in the vicinity of the gap of the main core, is in non-contact with the main core and is in the same plane as the main core, and a part of the leakage flux of the main core flows. The magnetosensitive element is a Hall element, and exists in a position where the magnetic field generated by the residual magnetization of the main core and the magnetic field generated by the residual magnetization of the sub core are weakened in the gap of the main core.
特許文献6に記載された電流センサは、電流センサ本体と、内側磁気シールドケースと、外側磁気シールドケースとを備える。内側磁気シールドケースの分割方向と、外側磁気シールドケースの分割方向とは互いに交差している。内側磁気シールドケースは、電流センサ本体の周りを囲み、外側磁気シールドケースは、内側磁気シールドケースの周りを囲んでいる。
The current sensor described in Patent Document 6 includes a current sensor body, an inner magnetic shield case, and an outer magnetic shield case. The dividing direction of the inner magnetic shield case and the dividing direction of the outer magnetic shield case intersect each other. The inner magnetic shield case surrounds the current sensor body, and the outer magnetic shield case surrounds the inner magnetic shield case.
特許文献1,2に記載された電流センサにおいては、磁化した磁気シールド体の残留磁化により発生する磁界の影響により、バスバーを流れる電流が0Aの状態においてもセンサ出力が発生し、測定誤差が生じる。
In the current sensors described in Patent Documents 1 and 2, due to the influence of the magnetic field generated by the residual magnetization of the magnetized magnetic shield body, the sensor output is generated even when the current flowing through the bus bar is 0 A, resulting in a measurement error. .
特許文献3,4,6に記載された電流センサにおいては、特許文献1,2に記載された電流センサより、磁気シールド体の残留磁化により発生する磁界の影響は小さくなるが、不十分である。
In the current sensors described in Patent Documents 3, 4, and 6, the influence of the magnetic field generated by the residual magnetization of the magnetic shield body is smaller than that of the current sensors described in Patent Documents 1 and 2, but is insufficient. .
特許文献5に記載された電流センサにおいては、特許文献1,2に記載された電流センサより、磁気シールド体の残留磁化により発生する磁界の影響は小さくなるが、メインコアとサブコアと感磁素子とを適切な位置に配置する必要があり、高い組み立て精度が求められ、電流センサの製造が困難である。
In the current sensor described in Patent Document 5, the influence of the magnetic field generated by the residual magnetization of the magnetic shield body is smaller than that of the current sensors described in Patent Documents 1 and 2, but the main core, the sub-core, and the magnetosensitive element. Are required to be arranged at appropriate positions, high assembly accuracy is required, and the manufacture of the current sensor is difficult.
本発明は上記の問題点に鑑みてなされたものであって、残留磁化により発生する磁界による測定誤差が低減されつつ容易に製造可能な電流センサを提供することを目的とする。
The present invention has been made in view of the above problems, and an object of the present invention is to provide a current sensor that can be easily manufactured while reducing a measurement error due to a magnetic field generated by residual magnetization.
本発明に基づく電流センサは、測定対象の電流が流れる1次導体と、1次導体を流れる上記電流により発生する磁界の強さを検出する少なくとも1つの磁気センサと、上記電流が流れる方向から見て、それぞれL字形状を有する1対の磁性体部材とを備える。1対の磁性体部材は、上記電流が流れる方向から見て、互いの端部同士の間に空隙が設けられた矩形形状を成し、1次導体および磁気センサの周りを囲んでいる。
A current sensor according to the present invention includes a primary conductor through which a current to be measured flows, at least one magnetic sensor for detecting the strength of a magnetic field generated by the current flowing through the primary conductor, and a direction in which the current flows. And a pair of magnetic members each having an L shape. The pair of magnetic members has a rectangular shape in which a gap is provided between the ends when viewed from the direction in which the current flows, and surrounds the primary conductor and the magnetic sensor.
本発明の一形態においては、1次導体は、平板形状を有する。磁気センサは、1次導体の厚さ方向および上記電流が流れる方向の両方と直交する方向の磁界を検出可能とされている。
In one embodiment of the present invention, the primary conductor has a flat plate shape. The magnetic sensor can detect a magnetic field in a direction orthogonal to both the thickness direction of the primary conductor and the direction in which the current flows.
本発明の一形態においては、磁気センサは、1次導体の幅方向における中央部の、1次導体の厚さ方向における一方側および他方側の少なくとも一方に配置されている。
In one embodiment of the present invention, the magnetic sensor is disposed at least one of the one side and the other side in the thickness direction of the primary conductor in the central portion in the width direction of the primary conductor.
本発明の一形態においては、電流センサは、磁気センサとして第1磁気センサと第2磁気センサとを備える。第1磁気センサと第2磁気センサとは、1次導体を挟んで互いに対向して位置している。
In one embodiment of the present invention, the current sensor includes a first magnetic sensor and a second magnetic sensor as magnetic sensors. The first magnetic sensor and the second magnetic sensor are positioned to face each other with the primary conductor interposed therebetween.
本発明の一形態においては、電流センサは、第1磁気センサの検出値と第2磁気センサの検出値とを演算することにより上記電流の値を算出する算出部をさらに備える。1次導体を流れる上記電流により発生する磁界の強さについて、第1磁気センサの検出値の位相と第2磁気センサの検出値の位相とが逆相である。算出部が減算器または差動増幅器である。
In one embodiment of the present invention, the current sensor further includes a calculation unit that calculates the value of the current by calculating the detection value of the first magnetic sensor and the detection value of the second magnetic sensor. Regarding the strength of the magnetic field generated by the current flowing through the primary conductor, the phase of the detection value of the first magnetic sensor and the phase of the detection value of the second magnetic sensor are opposite in phase. The calculation unit is a subtractor or a differential amplifier.
本発明の一形態においては、電流センサは、第1磁気センサの検出値と第2磁気センサの検出値とを演算することにより上記電流の値を算出する算出部をさらに備える。1次導体を流れる上記電流により発生する磁界の強さについて、第1磁気センサの検出値の位相と第2磁気センサの検出値の位相とが同相である。算出部が加算器または加算増幅器である。
In one embodiment of the present invention, the current sensor further includes a calculation unit that calculates the value of the current by calculating the detection value of the first magnetic sensor and the detection value of the second magnetic sensor. Regarding the strength of the magnetic field generated by the current flowing through the primary conductor, the phase of the detection value of the first magnetic sensor and the phase of the detection value of the second magnetic sensor are in phase. The calculation unit is an adder or a summing amplifier.
本発明の一形態においては、電流センサは、上記電流が流れる方向から見て、それぞれL字形状を有する他の1対の磁性体部材とをさらに備える。他の1対の磁性体部材は、上記電流が流れる方向から見て、互いの端部同士の間に空隙が設けられた矩形形状を成し、1対の磁性体部材に対して間隔を置いて1対の磁性体部材の周りを囲んでいる。他の1対の磁性体部材の空隙は、1対の磁性体部材の各々の角部の外側に位置している。
In one embodiment of the present invention, the current sensor further includes another pair of magnetic members each having an L shape when viewed from the direction in which the current flows. The other pair of magnetic members has a rectangular shape with a gap provided between the ends when viewed from the direction in which the current flows, and is spaced from the pair of magnetic members. Surrounding a pair of magnetic members. The gaps of the other pair of magnetic members are located outside the corners of each pair of magnetic members.
本発明によれば、残留磁化により発生する磁界による測定誤差が低減された電流センサを容易に製造できる。
According to the present invention, it is possible to easily manufacture a current sensor in which a measurement error due to a magnetic field generated by residual magnetization is reduced.
以下、本発明の各実施形態に係る電流センサについて図を参照して説明する。以下の実施形態の説明においては、図中の同一または相当部分には同一符号を付して、その説明は繰り返さない。
Hereinafter, the current sensor according to each embodiment of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.
(実施形態1)
図1は、本発明の実施形態1に係る電流センサの外観を示す斜視図である。図2は、図1の電流センサを矢印II方向から見た側面図である。図3は、図2の電流センサをIII-III線矢印方向から見た断面図である。図4は、本発明の実施形態1に係る電流センサの構成を示す分解斜視図である。図5は、本発明の実施形態1に係る電流センサの回路基板の外観を示す斜視図である。図6は、本発明の実施形態1に係る電流センサの回路構成を示す回路図である。図1~3においては、後述する1次導体110の幅方向をX軸方向、1次導体110の長さ方向をY軸方向、1次導体110の厚さ方向をZ軸方向として、図示している。 (Embodiment 1)
FIG. 1 is a perspective view showing an appearance of a current sensor according toEmbodiment 1 of the present invention. FIG. 2 is a side view of the current sensor of FIG. 1 viewed from the direction of arrow II. FIG. 3 is a cross-sectional view of the current sensor of FIG. 2 as viewed from the direction of arrows III-III. FIG. 4 is an exploded perspective view showing the configuration of the current sensor according to Embodiment 1 of the present invention. FIG. 5 is a perspective view showing an appearance of a circuit board of the current sensor according to the first embodiment of the present invention. FIG. 6 is a circuit diagram showing a circuit configuration of the current sensor according to Embodiment 1 of the present invention. 1 to 3, the width direction of a primary conductor 110, which will be described later, is illustrated as an X-axis direction, the length direction of the primary conductor 110 is defined as a Y-axis direction, and the thickness direction of the primary conductor 110 is illustrated as a Z-axis direction. ing.
図1は、本発明の実施形態1に係る電流センサの外観を示す斜視図である。図2は、図1の電流センサを矢印II方向から見た側面図である。図3は、図2の電流センサをIII-III線矢印方向から見た断面図である。図4は、本発明の実施形態1に係る電流センサの構成を示す分解斜視図である。図5は、本発明の実施形態1に係る電流センサの回路基板の外観を示す斜視図である。図6は、本発明の実施形態1に係る電流センサの回路構成を示す回路図である。図1~3においては、後述する1次導体110の幅方向をX軸方向、1次導体110の長さ方向をY軸方向、1次導体110の厚さ方向をZ軸方向として、図示している。 (Embodiment 1)
FIG. 1 is a perspective view showing an appearance of a current sensor according to
図1~6に示すように、本発明の実施形態1に係る電流センサ100は、測定対象の電流が流れる1次導体110と、1次導体110を流れる電流により発生する磁界の強さを検出する2つの磁気センサとを備える。2つの磁気センサは、第1磁気センサ120aおよび第2磁気センサ120bから構成されている。本実施形態においては、電流センサ100は、2つの磁気センサを備えているが、これに限られず、少なくとも1つの磁気センサを備えていればよい。
As shown in FIGS. 1 to 6, the current sensor 100 according to the first embodiment of the present invention detects the primary conductor 110 through which the current to be measured flows and the strength of the magnetic field generated by the current through the primary conductor 110. Two magnetic sensors. The two magnetic sensors are composed of a first magnetic sensor 120a and a second magnetic sensor 120b. In the present embodiment, the current sensor 100 includes two magnetic sensors. However, the present invention is not limited to this, and it is only necessary to include at least one magnetic sensor.
さらに、電流センサ100は、1次導体110を電流が流れる方向(Y軸方向)から見て、それぞれL字形状を有する1対の磁性体部材170を備える。具体的には、1対の磁性体部材170は、第1磁性体部材171および第2磁性体部材172から構成されている。1対の磁性体部材170は、1次導体110を流れる電流が流れる方向(Y軸方向)から見て、互いの端部同士の間に空隙173が設けられた矩形形状を成し、1次導体110および2つの磁気センサの周りを囲んでいる。具体的には、1対の磁性体部材170は、後述する、第1回路基板160a、第2回路基板160b、および、第1回路基板160aと第2回路基板160bとに挟まれた部分の1次導体110に対して間隔を置いて周りを囲んでいる。
Furthermore, the current sensor 100 includes a pair of magnetic members 170 each having an L shape when the primary conductor 110 is viewed from the direction in which current flows (Y-axis direction). Specifically, the pair of magnetic members 170 includes a first magnetic member 171 and a second magnetic member 172. The pair of magnetic members 170 has a rectangular shape in which a gap 173 is provided between ends of each other when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). Surrounding the conductor 110 and the two magnetic sensors. Specifically, the pair of magnetic members 170 includes a first circuit board 160a, a second circuit board 160b, and a portion sandwiched between the first circuit board 160a and the second circuit board 160b, which will be described later. It surrounds the second conductor 110 with a space.
1次導体110、第1回路基板160a、第2回路基板160b、および、1対の磁性体部材170の各々の相対位置は、図示しないケースなどにより維持されている。ケースは、ポリフェニレンスルファイドなどの高温耐性を有するエンジニアリングプラスティックなどで形成されていることが好ましい。第1回路基板160aおよび第2回路基板160bの各々とケースとをネジにより締結する場合には、磁場の乱れが生じないように、非磁性材料からなるネジで締結されていることが好ましい。
The relative positions of the primary conductor 110, the first circuit board 160a, the second circuit board 160b, and the pair of magnetic members 170 are maintained by a case (not shown). The case is preferably formed of an engineering plastic having high temperature resistance such as polyphenylene sulfide. When each of the first circuit board 160a and the second circuit board 160b and the case are fastened with screws, it is preferably fastened with screws made of a non-magnetic material so as not to disturb the magnetic field.
以下、各構成について詳細に説明する。
本実施形態においては、1次導体110は、平板形状を有している。1次導体110は、1次導体110の表面から裏面まで貫通した1つの貫通部を有している。具体的には、1次導体110の幅方向における中央部に、平面視にて円形の貫通孔110hが設けられている。電流は、1次導体110をY軸方向に流れる。 Hereinafter, each configuration will be described in detail.
In the present embodiment, theprimary conductor 110 has a flat plate shape. The primary conductor 110 has one penetrating portion that penetrates from the front surface to the back surface of the primary conductor 110. Specifically, a circular through hole 110h is provided in a central portion in the width direction of the primary conductor 110 in a plan view. The current flows through the primary conductor 110 in the Y-axis direction.
本実施形態においては、1次導体110は、平板形状を有している。1次導体110は、1次導体110の表面から裏面まで貫通した1つの貫通部を有している。具体的には、1次導体110の幅方向における中央部に、平面視にて円形の貫通孔110hが設けられている。電流は、1次導体110をY軸方向に流れる。 Hereinafter, each configuration will be described in detail.
In the present embodiment, the
本実施形態においては、1次導体110は、銅で構成されている。ただし、1次導体110の材料はこれに限られず、銀、アルミニウムなどの金属またはこれらの金属を含む合金でもよい。1次導体110は、表面処理が施されていてもよい。たとえば、ニッケル、錫、銀、銅などの金属またはこれらの金属を含む合金からなる、少なくとも1層のめっき層が、1次導体110の表面に設けられていてもよい。
In the present embodiment, the primary conductor 110 is made of copper. However, the material of the primary conductor 110 is not limited to this, and may be a metal such as silver or aluminum or an alloy containing these metals. The primary conductor 110 may be subjected to a surface treatment. For example, at least one plating layer made of a metal such as nickel, tin, silver, copper, or an alloy containing these metals may be provided on the surface of the primary conductor 110.
本実施形態においては、薄板をプレス加工することにより1次導体110が形成されている。ただし、1次導体110の形成方法はこれに限られず、切削または鋳造などの方法によって1次導体110が形成されてもよい。
In the present embodiment, the primary conductor 110 is formed by pressing a thin plate. However, the method of forming the primary conductor 110 is not limited to this, and the primary conductor 110 may be formed by a method such as cutting or casting.
本実施形態においては、第1磁気センサ120aは、第1オペアンプ140aおよび第1受動素子150aとともに第1プリント基板130aに実装されている。第1磁気センサ120aは、第1プリント基板130aの中央に配置されている。第1磁気センサ120a、第1プリント基板130a、第1オペアンプ140aおよび第1受動素子150aは、第1回路基板160aを構成している。第1プリント基板130aは、ガラスエポキシまたはアルミナからなる基板、および、基板上に銅箔などの金属箔がパターニングされて形成された配線を含む。第1回路基板160aには、第1磁気センサ120aからの信号を演算する演算回路が構成されている。
In the present embodiment, the first magnetic sensor 120a is mounted on the first printed circuit board 130a together with the first operational amplifier 140a and the first passive element 150a. The first magnetic sensor 120a is disposed at the center of the first printed circuit board 130a. The first magnetic sensor 120a, the first printed board 130a, the first operational amplifier 140a, and the first passive element 150a constitute a first circuit board 160a. The first printed circuit board 130a includes a substrate made of glass epoxy or alumina, and wiring formed by patterning a metal foil such as a copper foil on the substrate. The first circuit board 160a is configured with an arithmetic circuit that calculates a signal from the first magnetic sensor 120a.
第2磁気センサ120bは、第2オペアンプ140bおよび第2受動素子150bとともに第2プリント基板130bに実装されている。第2磁気センサ120bは、第2プリント基板130bの中央に配置されている。第2磁気センサ120b、第2プリント基板130b、第2オペアンプ140bおよび第2受動素子150bは、第2回路基板160bを構成している。第2プリント基板130bは、ガラスエポキシまたはアルミナからなる基板、および、基板上に銅箔などの金属箔がパターニングされて形成された配線を含む。第2回路基板160bには、第2磁気センサ120bからの信号を演算する演算回路が構成されている。
The second magnetic sensor 120b is mounted on the second printed circuit board 130b together with the second operational amplifier 140b and the second passive element 150b. The second magnetic sensor 120b is disposed at the center of the second printed circuit board 130b. The second magnetic sensor 120b, the second printed board 130b, the second operational amplifier 140b, and the second passive element 150b constitute a second circuit board 160b. Second printed circuit board 130b includes a substrate made of glass epoxy or alumina, and a wiring formed by patterning a metal foil such as a copper foil on the substrate. The second circuit board 160b is configured with an arithmetic circuit that calculates a signal from the second magnetic sensor 120b.
第1回路基板160aは、1次導体110の表面上に載置されている。第1磁気センサ120aは、第1プリント基板130aを1次導体110との間に挟んで、貫通孔110hの直上に位置している。第2回路基板160bは、1次導体110の裏面上に配置されている。第2磁気センサ120bは、第2プリント基板130bを1次導体110との間に挟んで、貫通孔110hの直下に位置している。
The first circuit board 160a is placed on the surface of the primary conductor 110. The first magnetic sensor 120a is located immediately above the through hole 110h with the first printed board 130a sandwiched between the primary conductor 110. The second circuit board 160 b is disposed on the back surface of the primary conductor 110. The second magnetic sensor 120b is located directly below the through hole 110h with the second printed board 130b sandwiched between the primary conductor 110.
すなわち、第1磁気センサ120aと第2磁気センサ120bとは、1次導体110を挟んで互いに反対側に位置している。第1磁気センサ120aは、1次導体110の幅方向(X軸方向)における中央部の、1次導体110の厚さ方向(Z軸方向)における一方側(上方側)に配置されている。第2磁気センサ120bは、1次導体110の幅方向(X軸方向)における中央部の、1次導体110の厚さ方向(Z軸方向)における他方側(下方側)に配置されている。
That is, the first magnetic sensor 120a and the second magnetic sensor 120b are located on opposite sides of the primary conductor 110. The first magnetic sensor 120 a is disposed on one side (upper side) in the thickness direction (Z-axis direction) of the primary conductor 110 in the central portion in the width direction (X-axis direction) of the primary conductor 110. The second magnetic sensor 120b is disposed on the other side (lower side) in the thickness direction (Z-axis direction) of the primary conductor 110 at the center in the width direction (X-axis direction) of the primary conductor 110.
第1磁気センサ120aおよび第2磁気センサ120bの各々の検出軸の方向(感磁方向)は、1次導体110の幅方向(X軸方向)である。すなわち、第1磁気センサ120aおよび第2磁気センサ120bの各々は、1次導体110の厚さ方向(Z軸方向)および1次導体110を電流が流れる方向(Y軸方向)の両方と直交する方向(X軸方向)の磁界を検出可能とされている。
The direction (magnetic direction) of the detection axis of each of the first magnetic sensor 120a and the second magnetic sensor 120b is the width direction (X-axis direction) of the primary conductor 110. That is, each of the first magnetic sensor 120a and the second magnetic sensor 120b is orthogonal to both the thickness direction (Z-axis direction) of the primary conductor 110 and the direction in which the current flows through the primary conductor 110 (Y-axis direction). The magnetic field in the direction (X-axis direction) can be detected.
第1磁気センサ120aおよび第2磁気センサ120bの各々は、検出軸の一方向に向いた磁界を検出した場合に正の値で出力し、かつ、検出軸の一方向とは反対方向に向いた磁界を検出した場合に負の値で出力する、入出力特性を有している。
Each of the first magnetic sensor 120a and the second magnetic sensor 120b outputs a positive value when a magnetic field directed in one direction of the detection axis is detected, and is directed in a direction opposite to the one direction of the detection axis. It has an input / output characteristic that outputs a negative value when a magnetic field is detected.
第1磁気センサ120aおよび第2磁気センサ120bの各々は、4つのAMR(Anisotropic Magneto Resistance)素子からなるホイートストンブリッジ型のブリッジ回路を有する。なお、第1磁気センサ120aおよび第2磁気センサ120bの各々が、AMR素子に代えて、GMR(Giant Magneto Resistance)、TMR(Tunnel Magneto Resistance)、BMR(Balistic Magneto Resistance)、CMR(Colossal Magneto Resistance)などの磁気抵抗素子を有していてもよい。また、第1磁気センサ120aおよび第2磁気センサ120bの各々が、2つの磁気抵抗素子からなるハーフ・ブリッジ回路を有していてもよい。その他にも、第1磁気センサ120aおよび第2磁気センサ120bとして、ホール素子を有する磁気センサ、磁気インピーダンス効果を利用するMI(Magneto Impedance)素子を有する磁気センサまたはフラックスゲート型磁気センサなどを用いることができる。磁気抵抗素子およびホール素子などの磁気素子は、樹脂パッケージされていてもよく、または、シリコーン樹脂若しくはエポキシ樹脂などでポッティングされていてもよい。
Each of the first magnetic sensor 120a and the second magnetic sensor 120b has a Wheatstone bridge type bridge circuit including four AMR (Anisotropic Magneto Resistance) elements. Each of the first magnetic sensor 120a and the second magnetic sensor 120b is replaced with an AMR element, and GMR (Giant Magneto Resistance), TMR (Tunnel Magneto Resistance), BMR (Balistic Magneto Resistance), CMR (Colossal Magneto Resistance). It may have a magnetoresistive element. Further, each of the first magnetic sensor 120a and the second magnetic sensor 120b may have a half bridge circuit including two magnetoresistive elements. In addition, as the first magnetic sensor 120a and the second magnetic sensor 120b, a magnetic sensor having a Hall element, a magnetic sensor having an MI (Magneto Impedance) element using a magnetic impedance effect, a fluxgate type magnetic sensor, or the like is used. Can do. Magnetic elements such as a magnetoresistive element and a Hall element may be packaged with a resin, or may be potted with a silicone resin or an epoxy resin.
第1磁気センサ120aおよび第2磁気センサ120bの各々のAMR素子は、バーバーポール型電極を含むことによって、奇関数入出力特性を有している。具体的には、第1磁気センサ120aおよび第2磁気センサ120bの各々のAMR素子は、バーバーポール型電極を含むことにより、所定の角度に電流が流れるようにバイアスされている。第1磁気センサ120aのAMR素子における磁気抵抗膜の磁化方向と、第2磁気センサ120bのAMR素子における磁気抵抗膜の磁化方向とは、同一方向である。これにより、外部磁界の影響による出力精度の低下を小さくすることができる。
Each AMR element of the first magnetic sensor 120a and the second magnetic sensor 120b has an odd function input / output characteristic by including a barber pole type electrode. Specifically, each AMR element of the first magnetic sensor 120a and the second magnetic sensor 120b includes a barber pole type electrode, and is biased so that a current flows at a predetermined angle. The magnetization direction of the magnetoresistive film in the AMR element of the first magnetic sensor 120a and the magnetization direction of the magnetoresistive film in the AMR element of the second magnetic sensor 120b are the same direction. Thereby, the fall of the output accuracy by the influence of an external magnetic field can be made small.
図6に示すように、電流センサ100は、第1磁気センサ120aの検出値と第2磁気センサ120bの検出値とを演算することにより1次導体110を流れる電流の値を算出する算出部190を備える。算出部190は、差動増幅器である。ただし、算出部190が減算器であってもよい。
As shown in FIG. 6, the current sensor 100 calculates the value of the current flowing through the primary conductor 110 by calculating the detection value of the first magnetic sensor 120a and the detection value of the second magnetic sensor 120b. Is provided. The calculation unit 190 is a differential amplifier. However, the calculation unit 190 may be a subtracter.
図1~3に示すように、第1磁性体部材171および第2磁性体部材172の各々は、第1板状部と、第1板状部に直交している第2板状部とを有している。第1磁性体部材171および第2磁性体部材172の各々の第1板状部と1次導体110とは、互いに平行に位置している。
As shown in FIGS. 1 to 3, each of the first magnetic member 171 and the second magnetic member 172 includes a first plate-like portion and a second plate-like portion orthogonal to the first plate-like portion. Have. The first plate-like portions of the first magnetic member 171 and the second magnetic member 172 and the primary conductor 110 are positioned in parallel to each other.
2つの空隙173の各々は、1次導体110を電流が流れる方向(Y軸方向)において、1対の磁性体部材170の一端から他端まで延在している。2つの空隙173の各々は、1次導体110を流れる電流が流れる方向(Y軸方向)から見て、1対の磁性体部材170が成す矩形形状の対角に位置している。1次導体110を流れる電流が流れる方向(Y軸方向)から見て、1対の磁性体部材170が成す矩形形状の中心位置と、1次導体110の貫通孔110hの位置とは重なっている。
Each of the two gaps 173 extends from one end of the pair of magnetic members 170 to the other end in the direction in which the current flows through the primary conductor 110 (Y-axis direction). Each of the two gaps 173 is located at a diagonal of a rectangular shape formed by the pair of magnetic members 170 when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). When viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction), the center position of the rectangular shape formed by the pair of magnetic members 170 and the position of the through hole 110h of the primary conductor 110 overlap. .
第1磁性体部材171および第2磁性体部材172の各々は、パーマロイで構成されているが、第1磁性体部材171および第2磁性体部材172の各々の材料は、パーマロイに限られず、軟鉄鋼、ケイ素鋼、電磁鋼、ニッケル合金、鉄合金またはフェライトなどの、透磁率および飽和磁束密度の高い磁性体材料であればよい。
Each of the first magnetic member 171 and the second magnetic member 172 is made of permalloy, but the material of each of the first magnetic member 171 and the second magnetic member 172 is not limited to permalloy, and is soft. Any magnetic material having high magnetic permeability and saturation magnetic flux density, such as iron steel, silicon steel, electromagnetic steel, nickel alloy, iron alloy, or ferrite, may be used.
本実施形態においては、薄板をプレス加工することにより第1磁性体部材171および第2磁性体部材172の各々が形成されている。ただし、第1磁性体部材171および第2磁性体部材172の各々の形成方法はこれに限られず、切削または鋳造などの方法によって第1磁性体部材171および第2磁性体部材172の各々が形成されてもよい。
In the present embodiment, each of the first magnetic member 171 and the second magnetic member 172 is formed by pressing a thin plate. However, the formation method of each of the first magnetic member 171 and the second magnetic member 172 is not limited to this, and each of the first magnetic member 171 and the second magnetic member 172 is formed by a method such as cutting or casting. May be.
ここで、貫通部を有さない比較例1の1次導体110、および、貫通孔110hが設けられた実施例1の1次導体110について、1次導体110の幅方向(X軸方向)における中央部の直上または直下の位置における、1次導体110の表面110sまたは裏面110tからの距離と磁束密度との関係をシミュレーション解析した結果について説明する。
Here, in the width direction (X-axis direction) of the primary conductor 110 with respect to the primary conductor 110 of Comparative Example 1 that does not have a through portion and the primary conductor 110 of Example 1 in which the through hole 110h is provided. The result of simulation analysis of the relationship between the distance from the front surface 110s or the back surface 110t of the primary conductor 110 and the magnetic flux density at a position immediately above or directly below the center will be described.
図7は、比較例1に係る1次導体の横断面形状を示す断面図である。図8は、実施例1に係る1次導体の横断面形状を示す断面図である。図7,8に示すように、比較例1および実施例1において、1次導体110の横断面の外形は、幅30mm、厚さ2.5mmとした。実施例1に係る1次導体110の幅方向の中央部に、直径2mmの貫通孔110hを設けた。比較例1および実施例1において、1次導体110を流れる電流の値を100Aとして、図7,8に示すように、1次導体110の幅方向の中央部の直上または直下に位置する基準線1上における磁束密度分布をシミュレーション解析により算出した。なお、比較例1および実施例1においては、1対の磁性体部材170は配置していない。
FIG. 7 is a cross-sectional view showing the cross-sectional shape of the primary conductor according to Comparative Example 1. FIG. 8 is a cross-sectional view illustrating the cross-sectional shape of the primary conductor according to the first embodiment. As shown in FIGS. 7 and 8, in Comparative Example 1 and Example 1, the outer shape of the cross section of the primary conductor 110 was 30 mm wide and 2.5 mm thick. A through hole 110h having a diameter of 2 mm was provided at the center in the width direction of the primary conductor 110 according to the first embodiment. In Comparative Example 1 and Example 1, assuming that the value of the current flowing through the primary conductor 110 is 100A, as shown in FIGS. 7 and 8, the reference line located immediately above or immediately below the central portion in the width direction of the primary conductor 110 The magnetic flux density distribution on 1 was calculated by simulation analysis. In Comparative Example 1 and Example 1, the pair of magnetic members 170 is not disposed.
図9は、実施例1に係る1次導体の周囲に発生する磁界を模式的に示す断面図である。図9においては、図8と同一の断面視にて図示している。図10は、比較例1および実施例1に係る1次導体の幅方向の中央部の直上または直下に位置する基準線上における、1次導体の表面または裏面からの距離と1次導体の幅方向(X軸方向)の磁束密度との関係を示すグラフである。図10においては、縦軸に磁束密度(mT)、横軸に1次導体110の表面110sまたは裏面110tからの距離(mm)を示している。また、図10においては、実施例1に係る1次導体110のデータを実線で、比較例1に係る1次導体110のデータを点線で示している。
FIG. 9 is a cross-sectional view schematically showing a magnetic field generated around the primary conductor according to the first embodiment. In FIG. 9, the same sectional view as FIG. 8 is shown. FIG. 10 shows the distance from the front surface or the back surface of the primary conductor and the width direction of the primary conductor on the reference line located immediately above or directly below the central portion in the width direction of the primary conductor according to Comparative Example 1 and Example 1. It is a graph which shows the relationship with the magnetic flux density of (X-axis direction). In FIG. 10, the vertical axis represents the magnetic flux density (mT), and the horizontal axis represents the distance (mm) from the front surface 110s or the back surface 110t of the primary conductor 110. In FIG. 10, the data of the primary conductor 110 according to the first embodiment is indicated by a solid line, and the data of the primary conductor 110 according to the comparative example 1 is indicated by a dotted line.
図9に示すように、いわゆる右ねじの法則によって、貫通孔110hの左側に位置する1次導体110を流れる電流10により磁界110eが発生する。同様に、貫通孔110hの右側に位置する1次導体110を流れる電流10により磁界110eが発生する。
As shown in FIG. 9, the magnetic field 110e is generated by the current 10 flowing through the primary conductor 110 located on the left side of the through hole 110h according to the so-called right-handed screw law. Similarly, a magnetic field 110e is generated by the current 10 flowing through the primary conductor 110 located on the right side of the through hole 110h.
1次導体110の幅方向の中央部の直上に位置する基準線1上においては、貫通孔110hの左側に位置する1次導体110を流れる電流10により発生した磁界110eによるZ軸方向の磁束密度LZと、貫通孔110hの右側に位置する1次導体110を流れる電流10により発生した磁界110eによるZ軸方向の磁束密度RZとが、打ち消し合う。一方、貫通孔110hの左側に位置する1次導体110を流れる電流10により発生した磁界110eによるX軸方向の磁束密度LXと、貫通孔110hの右側に位置する1次導体110を流れる電流10により発生した磁界110eによるX軸方向の磁束密度RXとが、組み合わされる。
On the reference line 1 located immediately above the central portion in the width direction of the primary conductor 110, the magnetic flux density in the Z-axis direction due to the magnetic field 110e generated by the current 10 flowing through the primary conductor 110 located on the left side of the through hole 110h. LZ and the magnetic flux density RZ in the Z-axis direction due to the magnetic field 110e generated by the current 10 flowing through the primary conductor 110 located on the right side of the through hole 110h cancel each other. On the other hand, the magnetic flux density LX in the X-axis direction due to the magnetic field 110e generated by the current 10 flowing through the primary conductor 110 located on the left side of the through hole 110h and the current 10 flowing through the primary conductor 110 located on the right side of the through hole 110h. The magnetic flux density RX in the X-axis direction due to the generated magnetic field 110e is combined.
1次導体110の幅方向の中央部の直下に位置する基準線1上においては、貫通孔110hの左側に位置する1次導体110を流れる電流10により発生した磁界110eによるZ軸方向の磁束密度LZと、貫通孔110hの右側に位置する1次導体110を流れる電流10により発生した磁界110eによるZ軸方向の磁束密度RZとが、打ち消し合う。一方、貫通孔110hの左側に位置する1次導体110を流れる電流10により発生した磁界110eによるX軸方向の磁束密度LXと、貫通孔110hの右側に位置する1次導体110を流れる電流10により発生した磁界110eによるX軸方向の磁束密度RXとが、組み合わされる。
On the reference line 1 located immediately below the central portion in the width direction of the primary conductor 110, the magnetic flux density in the Z-axis direction due to the magnetic field 110e generated by the current 10 flowing through the primary conductor 110 located on the left side of the through hole 110h. LZ and the magnetic flux density RZ in the Z-axis direction due to the magnetic field 110e generated by the current 10 flowing through the primary conductor 110 located on the right side of the through hole 110h cancel each other. On the other hand, the magnetic flux density LX in the X-axis direction due to the magnetic field 110e generated by the current 10 flowing through the primary conductor 110 located on the left side of the through hole 110h and the current 10 flowing through the primary conductor 110 located on the right side of the through hole 110h. The magnetic flux density RX in the X-axis direction due to the generated magnetic field 110e is combined.
図10に示すように、比較例1に係る1次導体110の幅方向の中央部の直上に位置する基準線1上におけるX軸方向の磁束密度は、1次導体110の表面110sからの距離が大きくなるに従って低下している。一方、実施例1に係る1次導体110の幅方向の中央部の直上に位置する基準線1上におけるX軸方向の磁束密度は、1次導体110の表面110sからの距離が4mmに到達するまでは距離が大きくなるに従って増加し、1次導体110の表面110sから4mm以上10mm以下の位置においては略一定になっている。
As shown in FIG. 10, the magnetic flux density in the X-axis direction on the reference line 1 located immediately above the central portion in the width direction of the primary conductor 110 according to Comparative Example 1 is the distance from the surface 110 s of the primary conductor 110. Decreases as the value increases. On the other hand, the magnetic flux density in the X-axis direction on the reference line 1 located immediately above the central portion in the width direction of the primary conductor 110 according to the first embodiment reaches a distance of 4 mm from the surface 110s of the primary conductor 110. The distance increases as the distance increases, and is substantially constant at a position of 4 mm to 10 mm from the surface 110 s of the primary conductor 110.
実施例1に係る1次導体110の幅方向の中央部の直上に位置する基準線1上におけるX軸方向の磁束密度は、1次導体110の表面110sからの距離に関わらず、比較例に係る1次導体110の幅方向の中央部の直上に位置する基準線1上におけるX軸方向の磁束密度より低くなっている。これは、貫通孔110hの部分に、電流が流れていないためである。
The magnetic flux density in the X-axis direction on the reference line 1 located immediately above the central portion in the width direction of the primary conductor 110 according to Example 1 is the comparative example regardless of the distance from the surface 110s of the primary conductor 110. It is lower than the magnetic flux density in the X-axis direction on the reference line 1 located immediately above the central portion in the width direction of the primary conductor 110. This is because no current flows through the through hole 110h.
同様に、比較例1に係る1次導体110の幅方向の中央部の直下に位置する基準線1上におけるX軸方向の磁束密度は、1次導体110の裏面110tからの距離が大きくなるに従って低下している。一方、実施例1に係る1次導体110の幅方向の中央部の直下に位置する基準線1上におけるX軸方向の磁束密度は、1次導体110の裏面110tからの距離が4mmに到達するまでは距離が大きくなるに従って増加し、1次導体110の裏面110tから4mm以上10mm以下の位置においては略一定になっている。
Similarly, the magnetic flux density in the X-axis direction on the reference line 1 located immediately below the center in the width direction of the primary conductor 110 according to Comparative Example 1 increases as the distance from the back surface 110t of the primary conductor 110 increases. It is falling. On the other hand, the magnetic flux density in the X-axis direction on the reference line 1 located immediately below the central portion in the width direction of the primary conductor 110 according to the first embodiment reaches a distance of 4 mm from the back surface 110t of the primary conductor 110. The distance increases as the distance increases, and is substantially constant at a position of 4 mm to 10 mm from the back surface 110 t of the primary conductor 110.
実施例1に係る1次導体110の幅方向の中央部の直下に位置する基準線1上におけるX軸方向の磁束密度は、1次導体110の裏面110tからの距離に関わらず、比較例に係る1次導体110の幅方向の中央部の直下に位置する基準線1上におけるX軸方向の磁束密度より低くなっている。これは、貫通孔110hの部分に、電流が流れていないためである。
The magnetic flux density in the X-axis direction on the reference line 1 located immediately below the central portion in the width direction of the primary conductor 110 according to Example 1 is the comparative example regardless of the distance from the back surface 110t of the primary conductor 110. It is lower than the magnetic flux density in the X-axis direction on the reference line 1 located immediately below the central portion in the width direction of the primary conductor 110. This is because no current flows through the through hole 110h.
このシミュレーション解析の結果から分かるように、本実施形態に係る電流センサ100においては、第1磁気センサ120aを、1次導体110の貫通孔110hの直上の位置に配置することにより、第1磁気センサ120aに作用する磁束密度を低減することができる。よって、1次導体110に大電流が流れた場合においても、第1磁気センサ120aの磁気抵抗素子が磁気飽和することを抑制することができる。
As can be seen from the result of the simulation analysis, in the current sensor 100 according to the present embodiment, the first magnetic sensor 120a is disposed at a position immediately above the through hole 110h of the primary conductor 110, thereby providing the first magnetic sensor. The magnetic flux density acting on 120a can be reduced. Therefore, even when a large current flows through the primary conductor 110, it is possible to suppress the magnetic saturation of the magnetoresistive element of the first magnetic sensor 120a.
同様に、第2磁気センサ120bを、1次導体110の貫通孔110hの直下の位置に配置することにより、第2磁気センサ120bに作用する磁束密度を低減することができる。よって、1次導体110に大電流が流れた場合においても、第2磁気センサ120bの磁気抵抗素子が磁気飽和することを抑制することができる。
Similarly, by arranging the second magnetic sensor 120b at a position directly below the through hole 110h of the primary conductor 110, the magnetic flux density acting on the second magnetic sensor 120b can be reduced. Therefore, even when a large current flows through the primary conductor 110, it is possible to suppress magnetic saturation of the magnetoresistive element of the second magnetic sensor 120b.
図11は、磁気抵抗素子に作用する磁束密度と磁気抵抗素子の出力電圧との関係を示すグラフである。図11においては、縦軸に磁気抵抗素子の出力電圧、横軸に磁気抵抗素子に作用する磁束密度を示している。
FIG. 11 is a graph showing the relationship between the magnetic flux density acting on the magnetoresistive element and the output voltage of the magnetoresistive element. In FIG. 11, the vertical axis represents the output voltage of the magnetoresistive element, and the horizontal axis represents the magnetic flux density acting on the magnetoresistive element.
図11に示すように、磁気抵抗素子が磁気飽和していない第1領域T1においては、磁気抵抗素子に作用する磁束密度の増加に比例して磁気抵抗素子の出力電圧が増加する。磁気抵抗素子が磁気飽和している第2領域T2においては、磁気抵抗効果素子に作用する磁束密度が増加しても磁気抵抗素子の出力電圧はほとんど増加しない。
As shown in FIG. 11, in the first region T 1 where the magnetoresistive element is not magnetically saturated, the output voltage of the magnetoresistive element increases in proportion to the increase of the magnetic flux density acting on the magnetoresistive element. In the second region T 2 where the magnetoresistive element is magnetically saturated, the output voltage of the magnetoresistive element hardly increases even if the magnetic flux density acting on the magnetoresistive effect element increases.
本実施形態に係る電流センサ100においては、複雑な回路によらずに1次導体110に貫通孔110hを設けた簡易な構造で磁気抵抗素子に作用する磁束密度を低減することにより、第1磁気センサ120aおよび第2磁気センサ120bを第1領域T1にて動作させることができる。その結果、電流センサ100の入力ダイナミックレンジを拡大させることができ、電流センサ100によって大電流を正確に測定することが可能となる。
In the current sensor 100 according to the present embodiment, the first magnetism is reduced by reducing the magnetic flux density acting on the magnetoresistive element with a simple structure in which the through hole 110h is provided in the primary conductor 110 without using a complicated circuit. the sensor 120a and the second magnetic sensor 120b can be operated in the first region T 1. As a result, the input dynamic range of the current sensor 100 can be expanded, and a large current can be accurately measured by the current sensor 100.
また、第1磁気センサ120aを1次導体110の貫通孔110hの直上の位置に配置し、第2磁気センサ120bを1次導体110の貫通孔110hの直下の位置に配置することにより、第1磁気センサ120aおよび第2磁気センサ120bの各々に作用するX軸方向およびZ軸方向の磁束密度を低減することができるため、第1磁気センサ120aおよび第2磁気センサ120bの各々に加わる磁界の強度にばらつきが生ずることを抑制できる。その結果、電流センサ100によって被測定電流の大きさを安定して測定することができる。
In addition, the first magnetic sensor 120a is disposed at a position immediately above the through hole 110h of the primary conductor 110, and the second magnetic sensor 120b is disposed at a position immediately below the through hole 110h of the primary conductor 110, thereby Since the magnetic flux density in the X-axis direction and the Z-axis direction acting on each of the magnetic sensor 120a and the second magnetic sensor 120b can be reduced, the strength of the magnetic field applied to each of the first magnetic sensor 120a and the second magnetic sensor 120b. It is possible to suppress the occurrence of variations. As a result, the current sensor 100 can stably measure the magnitude of the current to be measured.
上記のように、実施例1に係る1次導体110の幅方向の中央部の直上または直下に位置する基準線1上において、1次導体110の表面110sまたは裏面110tから4mm以上10mm以下の位置は、X軸方向の磁束密度が略一定になっているロバスト領域である。
As described above, on the reference line 1 located immediately above or directly below the central portion in the width direction of the primary conductor 110 according to the first embodiment, a position of 4 mm to 10 mm from the front surface 110s or the back surface 110t of the primary conductor 110. Is a robust region in which the magnetic flux density in the X-axis direction is substantially constant.
本実施形態に係る電流センサ100においては、第1磁気センサ120aが、第1プリント基板130aを1次導体110との間に挟んで、貫通孔110hの直上に位置していることにより第1磁気センサ120aがロバスト領域内に位置している。すなわち、第1磁気センサ120aがロバスト領域内に位置するように、第1プリント基板130aの厚さを適宜設定している。
In the current sensor 100 according to the present embodiment, the first magnetic sensor 120a is positioned directly above the through hole 110h with the first printed board 130a interposed between the primary conductor 110 and the first magnetic sensor 120a. The sensor 120a is located in the robust area. That is, the thickness of the first printed circuit board 130a is appropriately set so that the first magnetic sensor 120a is positioned in the robust region.
同様に、電流センサ100においては、第2磁気センサ120bが、第2プリント基板130bを1次導体110との間に挟んで、貫通孔110hの直下に位置していることにより第2磁気センサ120bがロバスト領域内に位置している。すなわち、第2磁気センサ120bがロバスト領域内に位置するように、第2プリント基板130bの厚さを適宜設定している。
Similarly, in the current sensor 100, the second magnetic sensor 120b is located directly below the through hole 110h with the second printed circuit board 130b sandwiched between the primary conductor 110 and the second magnetic sensor 120b. Is located in the robust region. That is, the thickness of the second printed circuit board 130b is appropriately set so that the second magnetic sensor 120b is located in the robust region.
第1磁気センサ120aおよび第2磁気センサ120bの各々をロバスト領域内に位置させることにより、第1磁気センサ120aおよび第2磁気センサ120bの各々に加わる磁界の強度にばらつきが生ずることを安定して抑制できる。その結果、電流センサ100によって被測定電流の大きさをさらに安定して測定することができる。
By positioning each of the first magnetic sensor 120a and the second magnetic sensor 120b within the robust region, it is possible to stably cause variations in the strength of the magnetic field applied to each of the first magnetic sensor 120a and the second magnetic sensor 120b. Can be suppressed. As a result, the current sensor 100 can more stably measure the magnitude of the current to be measured.
図9に示すように、第1磁気センサ120aに作用するX軸方向の磁束の向きと、第2磁気センサ120bに作用するX軸方向磁束の向きとが反対であるため、1次導体110を流れる電流により発生する磁界の強さについて、第1磁気センサ120aの検出値の位相と、第2磁気センサ120bの検出値の位相とは、逆相である。
As shown in FIG. 9, since the direction of the magnetic flux in the X-axis direction acting on the first magnetic sensor 120a is opposite to the direction of the magnetic flux in the X-axis direction acting on the second magnetic sensor 120b, the primary conductor 110 is connected. Regarding the strength of the magnetic field generated by the flowing current, the phase of the detection value of the first magnetic sensor 120a is opposite to the phase of the detection value of the second magnetic sensor 120b.
よって、第1磁気センサ120aの検出した磁界の強さを正の値とすると、第2磁気センサ120bの検出した磁界の強さは負の値となる。第1磁気センサ120aの検出値と第2磁気センサ120bの検出値とは、算出部190に送信される。
Therefore, if the strength of the magnetic field detected by the first magnetic sensor 120a is a positive value, the strength of the magnetic field detected by the second magnetic sensor 120b is a negative value. The detection value of the first magnetic sensor 120a and the detection value of the second magnetic sensor 120b are transmitted to the calculation unit 190.
算出部190は、第1磁気センサ120aの検出値から第2磁気センサ120bの検出値を減算する。その結果、第1磁気センサ120aの検出値の絶対値と、第2磁気センサ120bの検出値の絶対値とが加算される。この加算結果から、1次導体110を流れた電流の値が算出される。
The calculation unit 190 subtracts the detection value of the second magnetic sensor 120b from the detection value of the first magnetic sensor 120a. As a result, the absolute value of the detection value of the first magnetic sensor 120a and the absolute value of the detection value of the second magnetic sensor 120b are added. From this addition result, the value of the current flowing through the primary conductor 110 is calculated.
本実施形態に係る電流センサ100においては、第1磁気センサ120aと第2磁気センサ120bとの間に、1次導体110、第1プリント基板130a、および第2プリント基板130bが位置しているため、外部磁界源は、物理的に第1磁気センサ120aと第2磁気センサ120bとの間に位置することができない。
In the current sensor 100 according to the present embodiment, the primary conductor 110, the first printed board 130a, and the second printed board 130b are located between the first magnetic sensor 120a and the second magnetic sensor 120b. The external magnetic field source cannot be physically located between the first magnetic sensor 120a and the second magnetic sensor 120b.
そのため、外部磁界源から第1磁気センサ120aに印加される磁界のうちの検出軸の方向における磁界成分の向きと、外部磁界源から第2磁気センサ120bに印加される磁界のうちの検出軸の方向における磁界成分の向きとは、同じ向きとなる。よって、第1磁気センサ120aの検出した外部磁界の強さを正の値とすると、第2磁気センサ120bの検出した外部磁界の強さも正の値となる。
Therefore, the direction of the magnetic field component in the direction of the detection axis of the magnetic field applied to the first magnetic sensor 120a from the external magnetic field source and the detection axis of the magnetic field applied to the second magnetic sensor 120b from the external magnetic field source. The direction of the magnetic field component in the direction is the same direction. Therefore, if the strength of the external magnetic field detected by the first magnetic sensor 120a is a positive value, the strength of the external magnetic field detected by the second magnetic sensor 120b is also a positive value.
その結果、算出部190が第1磁気センサ120aの検出値から第2磁気センサ120bの検出値を減算することにより、第1磁気センサ120aの検出値の絶対値と、第2磁気センサ120bの検出値の絶対値とが減算される。これにより、外部磁界源からの磁界は、ほとんど検出されなくなる。すなわち、外部磁界の影響が低減される。
As a result, the calculation unit 190 subtracts the detection value of the second magnetic sensor 120b from the detection value of the first magnetic sensor 120a, thereby detecting the absolute value of the detection value of the first magnetic sensor 120a and the detection of the second magnetic sensor 120b. The absolute value of the value is subtracted. Thereby, the magnetic field from the external magnetic field source is hardly detected. That is, the influence of the external magnetic field is reduced.
本実施形態の変形例として、第1磁気センサ120aおよび第2磁気センサ120bにおいて、検出値が正となる検出軸の方向を互いに反対方向(180°反対)にしてもよい。この場合、第1磁気センサ120aの検出する外部磁界の強さを正の値とすると、第2磁気センサ120bの検出する外部磁界の強さは負の値となる。
As a modification of the present embodiment, in the first magnetic sensor 120a and the second magnetic sensor 120b, the directions of the detection axes with positive detection values may be opposite to each other (opposite 180 °). In this case, if the strength of the external magnetic field detected by the first magnetic sensor 120a is a positive value, the strength of the external magnetic field detected by the second magnetic sensor 120b is a negative value.
一方、1次導体110を流れる電流により発生する磁界の強さについて、第1磁気センサ120aの検出値の位相と、第2磁気センサ120bの検出値の位相とは同相となる。
On the other hand, regarding the strength of the magnetic field generated by the current flowing through the primary conductor 110, the phase of the detection value of the first magnetic sensor 120a and the phase of the detection value of the second magnetic sensor 120b are in phase.
本変形例においては、算出部190として差動増幅器に代えて加算器または加算増幅器を用いる。外部磁界の強さについては、第1磁気センサ120aの検出値と第2磁気センサ120bの検出値とを加算器または加算増幅器によって加算することにより、第1磁気センサ120aの検出値の絶対値と、第2磁気センサ120bの検出値の絶対値とが減算される。これにより、外部磁界源からの磁界は、ほとんど検出されなくなる。すなわち、外部磁界の影響が低減される。
In this modification, an adder or an addition amplifier is used as the calculation unit 190 instead of the differential amplifier. Regarding the strength of the external magnetic field, the detected value of the first magnetic sensor 120a and the detected value of the second magnetic sensor 120b are added by an adder or an adding amplifier, thereby obtaining the absolute value of the detected value of the first magnetic sensor 120a. The absolute value of the detection value of the second magnetic sensor 120b is subtracted. Thereby, the magnetic field from the external magnetic field source is hardly detected. That is, the influence of the external magnetic field is reduced.
一方、1次導体110を流れる電流により発生する磁界の強さについては、第1磁気センサ120aの検出値と第2磁気センサ120bの検出値とを加算器または加算増幅器によって加算することにより、第1磁気センサ120aの検出値の絶対値と、第2磁気センサ120bの検出値の絶対値とが加算される。この加算結果から、1次導体110を流れた電流の値が算出される。
On the other hand, the strength of the magnetic field generated by the current flowing through the primary conductor 110 is obtained by adding the detection value of the first magnetic sensor 120a and the detection value of the second magnetic sensor 120b by an adder or an addition amplifier. The absolute value of the detection value of the first magnetic sensor 120a and the absolute value of the detection value of the second magnetic sensor 120b are added. From this addition result, the value of the current flowing through the primary conductor 110 is calculated.
このように、第1磁気センサ120aと第2磁気センサ120bとの入出力特性を互いに逆の極性にしつつ、差動増幅器に代えて加算器または加算増幅器を算出部として用いてもよい。
As described above, an adder or an addition amplifier may be used as the calculation unit in place of the differential amplifier while the input / output characteristics of the first magnetic sensor 120a and the second magnetic sensor 120b have opposite polarities.
図1,3に示すように、本実施形態に係る電流センサ100においては、第1磁気センサ120aおよび第2磁気センサ120bの各々は、1対の磁性体部材170に周りを囲まれているため、第1磁気センサ120aおよび第2磁気センサ120bの各々に誤差要因である外部磁界が到達することを抑制できる。その結果、第1磁気センサ120aおよび第2磁気センサ120bの各々が、不要な外部磁界を検知しないようにすることができる。すなわち、1対の磁性体部材170は、磁気シールドとして機能する。
As shown in FIGS. 1 and 3, in the current sensor 100 according to this embodiment, each of the first magnetic sensor 120 a and the second magnetic sensor 120 b is surrounded by a pair of magnetic members 170. The external magnetic field that is an error factor can be suppressed from reaching each of the first magnetic sensor 120a and the second magnetic sensor 120b. As a result, each of the first magnetic sensor 120a and the second magnetic sensor 120b can be prevented from detecting an unnecessary external magnetic field. That is, the pair of magnetic members 170 functions as a magnetic shield.
ここで、1対の磁性体部材における空隙の位置の影響を検証したシミュレーション解析結果および実測結果について説明する。本検証例においては、図1~6に示す構成を有する実施例2に係る電流センサ、後述する比較例2に係る電流センサ、および、比較例3に係る電流センサの3種類の電流センサについて検証を行なった。なお、以下の比較例2および比較例3に係る電流センサの説明においては、実施例2に係る電流センサと異なる点のみ説明し、実施例2に係る電流センサと同様である構成については説明を繰り返さない。
Here, a simulation analysis result and an actual measurement result in which the influence of the position of the air gap in the pair of magnetic members is verified will be described. In this verification example, three types of current sensors are verified: a current sensor according to Example 2 having the configuration shown in FIGS. 1 to 6, a current sensor according to Comparative Example 2 to be described later, and a current sensor according to Comparative Example 3. Was done. In the following description of the current sensor according to Comparative Example 2 and Comparative Example 3, only the differences from the current sensor according to Example 2 will be described, and the configuration similar to that of the current sensor according to Example 2 will be described. Do not repeat.
図12は、比較例2に係る電流センサの外観を示す斜視図である。図13は、図12の電流センサを矢印XIII方向から見た側面図である。図14は、図13の電流センサをXIV-XIV線矢印方向から見た断面図である。
FIG. 12 is a perspective view showing an appearance of the current sensor according to Comparative Example 2. FIG. FIG. 13 is a side view of the current sensor of FIG. 12 as viewed from the direction of the arrow XIII. FIG. 14 is a cross-sectional view of the current sensor of FIG. 13 as viewed from the direction of arrows XIV-XIV.
図12~14に示すように、比較例2に係る電流センサ200は、1次導体110を電流が流れる方向(Y軸方向)から見て、それぞれU字形状を有する1対の磁性体部材270を備える。具体的には、1対の磁性体部材270は、第1磁性体部材271および第2磁性体部材272から構成されている。1対の磁性体部材270は、1次導体110を流れる電流が流れる方向(Y軸方向)から見て、互いの端部同士の間に空隙273が設けられた矩形形状を成し、1次導体110および2つの磁気センサの周りを囲んでいる。具体的には、1対の磁性体部材270は、第1回路基板160a、第2回路基板160b、および、第1回路基板160aと第2回路基板160bとに挟まれた部分の1次導体110に対して間隔を置いて周りを囲んでいる。
As shown in FIGS. 12 to 14, the current sensor 200 according to Comparative Example 2 includes a pair of magnetic members 270 each having a U-shape when the primary conductor 110 is viewed from the direction in which current flows (Y-axis direction). Is provided. Specifically, the pair of magnetic members 270 includes a first magnetic member 271 and a second magnetic member 272. The pair of magnetic members 270 has a rectangular shape in which a gap 273 is provided between the ends when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). Surrounding the conductor 110 and the two magnetic sensors. Specifically, the pair of magnetic members 270 includes the first circuit board 160a, the second circuit board 160b, and the portion of the primary conductor 110 sandwiched between the first circuit board 160a and the second circuit board 160b. Is surrounded by a space.
第1磁性体部材271および第2磁性体部材272の各々は、第1板状部と、第1板状部にそれぞれ直交して互いに対向している、第2板状部および第3板状部とを有している。第1磁性体部材271および第2磁性体部材272の各々の第1板状部と1次導体110とは、互いに平行に位置している。
Each of the first magnetic member 271 and the second magnetic member 272 is a first plate-like portion and a second plate-like portion and a third plate-like shape that are orthogonal to the first plate-like portion and face each other. Part. The first plate-like portions of the first magnetic member 271 and the second magnetic member 272 and the primary conductor 110 are positioned in parallel to each other.
2つの空隙273の各々は、1次導体110を電流が流れる方向(Y軸方向)において、1対の磁性体部材270の一端から他端まで延在している。2つの空隙273の各々は、1次導体110を流れる電流が流れる方向(Y軸方向)から見て、1対の磁性体部材270が成す矩形形状の両側辺のZ軸方向の中央部に位置している。1次導体110を流れる電流が流れる方向(Y軸方向)から見て、1対の磁性体部材270が成す矩形形状の中心位置と、1次導体110の貫通孔110hの位置とは重なっている。
Each of the two air gaps 273 extends from one end of the pair of magnetic members 270 to the other end in the direction in which the current flows through the primary conductor 110 (Y-axis direction). Each of the two gaps 273 is located at the center in the Z-axis direction on both sides of the rectangular shape formed by the pair of magnetic members 270 when viewed from the direction (Y-axis direction) in which the current flowing through the primary conductor 110 flows. is doing. The center position of the rectangular shape formed by the pair of magnetic members 270 and the position of the through hole 110h of the primary conductor 110 overlap each other when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). .
図15は、比較例3に係る電流センサの外観を示す斜視図である。図16は、図15の電流センサを矢印XVI方向から見た平面図である。図17は、図16の電流センサをXVII-XVII線矢印方向から見た断面図である。
FIG. 15 is a perspective view showing an appearance of a current sensor according to Comparative Example 3. FIG. 16 is a plan view of the current sensor of FIG. 15 viewed from the direction of the arrow XVI. FIG. 17 is a cross-sectional view of the current sensor of FIG. 16 viewed from the direction of the arrow XVII-XVII.
図15~17に示すように、比較例3に係る電流センサ300は、1次導体110を電流が流れる方向(Y軸方向)から見て、それぞれU字形状を有する1対の磁性体部材370を備える。具体的には、1対の磁性体部材370は、第1磁性体部材371および第2磁性体部材372から構成されている。1対の磁性体部材370は、1次導体110を流れる電流が流れる方向(Y軸方向)から見て、互いの端部同士の間に空隙373が設けられた矩形形状を成し、1次導体110および2つの磁気センサの周りを囲んでいる。具体的には、1対の磁性体部材370は、第1回路基板160a、第2回路基板160b、および、第1回路基板160aと第2回路基板160bとに挟まれた部分の1次導体110に対して間隔を置いて周りを囲んでいる。
As shown in FIGS. 15 to 17, the current sensor 300 according to the third comparative example has a pair of magnetic members 370 each having a U shape when the primary conductor 110 is viewed from the direction in which the current flows (Y-axis direction). Is provided. Specifically, the pair of magnetic members 370 includes a first magnetic member 371 and a second magnetic member 372. The pair of magnetic members 370 has a rectangular shape in which a gap 373 is provided between the ends when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). Surrounding the conductor 110 and the two magnetic sensors. Specifically, the pair of magnetic members 370 includes a first circuit board 160a, a second circuit board 160b, and a portion of the primary conductor 110 sandwiched between the first circuit board 160a and the second circuit board 160b. Is surrounded by a space.
第1磁性体部材371および第2磁性体部材372の各々は、第1板状部と、第1板状部にそれぞれ直交して互いに対向している、第2板状部および第3板状部とを有している。第1磁性体部材371および第2磁性体部材372の各々の第1板状部と1次導体110とは、互いに平行に位置している。
Each of the first magnetic member 371 and the second magnetic member 372 has a first plate-like portion and a second plate-like portion and a third plate-like shape that are orthogonal to the first plate-like portion and face each other. Part. The first plate-like portions of the first magnetic member 371 and the second magnetic member 372 and the primary conductor 110 are positioned in parallel to each other.
2つの空隙373の各々は、1次導体110を電流が流れる方向(Y軸方向)において、1対の磁性体部材370の一端から他端まで延在している。2つの空隙373の各々は、1次導体110を流れる電流が流れる方向(Y軸方向)から見て、1対の磁性体部材370が成す矩形形状の上辺および下辺の各々のX軸方向の中央部に位置している。1次導体110を流れる電流が流れる方向(Y軸方向)から見て、1対の磁性体部材370が成す矩形形状の中心位置と、1次導体110の貫通孔110hの位置とは重なっている。
Each of the two gaps 373 extends from one end of the pair of magnetic members 370 to the other end in the direction in which the current flows through the primary conductor 110 (Y-axis direction). Each of the two air gaps 373 is the center in the X-axis direction of each of the upper and lower sides of the rectangular shape formed by the pair of magnetic members 370 when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). Located in the department. The center position of the rectangular shape formed by the pair of magnetic members 370 and the position of the through hole 110h of the primary conductor 110 overlap with each other when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). .
実施例2に係る電流センサ、比較例2に係る電流センサ、および、比較例3に係る電流センサの各々において、共通の条件について説明する。空隙173,273,373の大きさは、1mmとした。空隙173,273,373の大きさとは、第1磁性体部材171,271,371と第2磁性体部材172,272,372との最短距離である。
Common conditions in each of the current sensor according to the second embodiment, the current sensor according to the second comparative example, and the current sensor according to the third comparative example will be described. The size of the gaps 173, 273, and 373 was 1 mm. The size of the gaps 173, 273, 373 is the shortest distance between the first magnetic members 171, 271, 371 and the second magnetic members 172, 272, 372.
1対の磁性体部材170,270,370の外形は、長さの寸法が25.0mm、幅の寸法が23.0mm、高さの寸法が20.0mmとした。第1磁性体部材171,271,371および第2磁性体部材172,272,372の各々の板厚は、0.5mmとした。第1磁性体部材171,271,371および第2磁性体部材172,272,372の各々の材質は、42アロイ(42Ni)を用いた。
The outer shape of the pair of magnetic members 170, 270, and 370 was 25.0 mm in length, 23.0 mm in width, and 20.0 mm in height. The plate thickness of each of the first magnetic members 171, 271 and 371 and the second magnetic members 172, 272 and 372 was 0.5 mm. The material of each of the first magnetic members 171, 271, 371 and the second magnetic members 172, 272, 372 was 42 alloy (42Ni).
1次導体110の外形は、長さの寸法が80.0mm、幅の寸法が13.0mm、高さの寸法が1.5mmとした。1次導体110の材質は、無酸素銅(C1020)とした。
The outer dimensions of the primary conductor 110 were 80.0 mm in length, 13.0 mm in width, and 1.5 mm in height. The material of the primary conductor 110 was oxygen-free copper (C1020).
シミュレーション解析は、有限要素法を用いて、1対の磁性体部材170,270,370が一様に磁化した状態を仮定して行なった。図18は、1対の磁気シールドが一様に磁化した状態を示す模式図である。図18に示すように、1次導体110を紙面手前側から紙面奥側に向けて電流が流れることにより、1対の磁性体部材170,270,370は、1対の磁性体部材170,270,370が成す矩形形状を右回りに周回するように矢印2で示す方向に磁化する。
The simulation analysis was performed on the assumption that a pair of magnetic members 170, 270, and 370 were uniformly magnetized using the finite element method. FIG. 18 is a schematic diagram showing a state in which a pair of magnetic shields are uniformly magnetized. As shown in FIG. 18, when a current flows through the primary conductor 110 from the front side of the drawing to the back side of the drawing, the pair of magnetic members 170, 270, and 370 are paired with the pair of magnetic members 170, 270. , 370 is magnetized in the direction indicated by arrow 2 so as to circulate clockwise.
図19は、シミュレーション解析におけるZ軸方向の基準線および中心点を示す図である。図19に示すように、1次導体110の幅方向の中央部の直上または直下に位置する基準線1上における磁束密度分布をシミュレーション解析により算出した。1次導体110の厚さ方向の中心位置Oを、Z軸方向の原点とした。
FIG. 19 is a diagram showing a reference line and a center point in the Z-axis direction in the simulation analysis. As shown in FIG. 19, the magnetic flux density distribution on the reference line 1 located immediately above or directly below the central portion in the width direction of the primary conductor 110 was calculated by simulation analysis. The center position O in the thickness direction of the primary conductor 110 was set as the origin in the Z-axis direction.
図20は、実施例2、比較例2および比較例3に係る電流センサにおいて、1次導体の幅方向の中央部の直上または直下に位置する基準線上における、1次導体の厚さ方向の中心位置からの距離と1次導体の幅方向(X軸方向)の磁束密度との関係を示すグラフである。
FIG. 20 shows the center of the primary conductor in the thickness direction on the reference line located immediately above or directly below the central portion in the width direction of the primary conductor in the current sensors according to Example 2, Comparative Example 2 and Comparative Example 3. It is a graph which shows the relationship between the distance from a position, and the magnetic flux density of the width direction (X-axis direction) of a primary conductor.
図21は、実施例2、比較例2および比較例3に係る電流センサにおいて、1次導体の幅方向の中央部の直上または直下に位置する基準線上における、1次導体の厚さ方向の中心位置からの距離と1次導体の長さ方向(Y軸方向)の磁束密度との関係を示すグラフである。
FIG. 21 shows the center in the thickness direction of the primary conductor on the reference line located immediately above or directly below the center portion in the width direction of the primary conductor in the current sensors according to Example 2, Comparative Example 2 and Comparative Example 3. It is a graph which shows the relationship between the distance from a position, and the magnetic flux density of the length direction (Y-axis direction) of a primary conductor.
図22は、実施例2、比較例2および比較例3に係る電流センサにおいて、1次導体の幅方向の中央部の直上または直下に位置する基準線上における、1次導体の厚さ方向の中心位置からの距離と1次導体の厚さ方向(Z軸方向)の磁束密度との関係を示すグラフである。
FIG. 22 shows the center in the thickness direction of the primary conductor on the reference line located immediately above or directly below the central portion in the width direction of the primary conductor in the current sensors according to Example 2, Comparative Example 2 and Comparative Example 3. It is a graph which shows the relationship between the distance from a position, and the magnetic flux density of the thickness direction (Z-axis direction) of a primary conductor.
図20~22においては、縦軸に、規格化した磁束密度、横軸に、1次導体110の厚さ方向の中心位置OからのZ軸方向の距離(mm)を示している。図20~22においては、実施例2に係る電流センサ100のデータを実線で、比較例2に係る電流センサ200のデータを点線で、比較例3に係る電流センサ300のデータを1点鎖線で示している。図20~22の各々の図中に、第1磁気センサ120aおよび第2磁気センサ120bの各々のAMR素子の配置位置121を示している。
20 to 22, the vertical axis represents the normalized magnetic flux density, and the horizontal axis represents the distance (mm) in the Z-axis direction from the center position O in the thickness direction of the primary conductor 110. 20 to 22, the data of the current sensor 100 according to the second embodiment is indicated by a solid line, the data of the current sensor 200 according to the comparative example 2 is indicated by a dotted line, and the data of the current sensor 300 according to the comparative example 3 is indicated by a one-dot chain line. Show. In each of FIGS. 20 to 22, the arrangement positions 121 of the AMR elements of the first magnetic sensor 120a and the second magnetic sensor 120b are shown.
図20に示すように、比較例2に係る電流センサ200および比較例3に係る電流センサ300の各々は、AMR素子の配置位置121において、第1磁気センサ120aおよび第2磁気センサ120bの各々の検出軸の方向(X軸方向)の規格化磁束密度Bxが、絶対値にて0.3~0.5程度であった。
As illustrated in FIG. 20, each of the current sensor 200 according to the comparative example 2 and the current sensor 300 according to the comparative example 3 includes the first magnetic sensor 120 a and the second magnetic sensor 120 b at the arrangement position 121 of the AMR element. The normalized magnetic flux density Bx in the detection axis direction (X-axis direction) was about 0.3 to 0.5 in absolute value.
実施例2に係る電流センサ100は、AMR素子の配置位置121において、第1磁気センサ120aおよび第2磁気センサ120bの各々の検出軸の方向(X軸方向)の規格化磁束密度Bxが、0.1以下であり、比較例2に係る電流センサ200および比較例3に係る電流センサ300に比較して小さかった。
In the current sensor 100 according to the second embodiment, the normalized magnetic flux density Bx in the detection axis direction (X-axis direction) of each of the first magnetic sensor 120a and the second magnetic sensor 120b is 0 at the AMR element arrangement position 121. .1 or less, which is smaller than the current sensor 200 according to Comparative Example 2 and the current sensor 300 according to Comparative Example 3.
図21,22に示すように、実施例2に係る電流センサ100、比較例2に係る電流センサ200および比較例3に係る電流センサ300の各々は、AMR素子の配置位置121において、Y軸方向の規格化磁束密度ByおよびZ軸方向の規格化磁束密度Bzの各々が、略0であり、差は認められなかった。
As shown in FIGS. 21 and 22, each of the current sensor 100 according to the second embodiment, the current sensor 200 according to the second comparative example, and the current sensor 300 according to the third comparative example is arranged in the Y-axis direction at the arrangement position 121 of the AMR element. Each of the normalized magnetic flux density By and the normalized magnetic flux density Bz in the Z-axis direction was substantially 0, and no difference was recognized.
このシミュレーション解析結果から、1対の磁性体部材の残留磁化により発生する磁界による測定誤差を低減するためには、第1磁気センサ120aおよび第2磁気センサ120bの各々の検出軸の方向(X軸方向)の規格化磁束密度Bxが小さい、実施例2に係る電流センサ100が、優れていることが確認された。
From this simulation analysis result, in order to reduce the measurement error due to the magnetic field generated by the remanent magnetization of the pair of magnetic members, the directions of the detection axes of the first magnetic sensor 120a and the second magnetic sensor 120b (X-axis) It was confirmed that the current sensor 100 according to Example 2 having a small (direction) normalized magnetic flux density Bx was excellent.
次に、実施例2に係る電流センサ100、比較例2に係る電流センサ200および比較例3に係る電流センサ300の各々において、1次導体110を流れる入力電流値と、図6に示すOutput部から出力されるセンサ出力電圧との関係を実測した結果について説明する。
Next, in each of the current sensor 100 according to the second embodiment, the current sensor 200 according to the second comparative example, and the current sensor 300 according to the third comparative example, an input current value flowing through the primary conductor 110 and the output unit illustrated in FIG. The result of actual measurement of the relationship with the sensor output voltage output from will be described.
図23は、実施例2に係る電流センサにおける入力電流値とセンサ出力電圧との関係を示すグラフである。図24は、図23における入力電流値の0A近傍部3を拡大して示すグラフである。図25は、比較例2に係る電流センサにおける入力電流値とセンサ出力電圧との関係を示すグラフである。図26は、図25における入力電流値の0A近傍部3を拡大して示すグラフである。図27は、比較例3に係る電流センサにおける入力電流値とセンサ出力電圧との関係を示すグラフである。図28は、図27における入力電流値の0A近傍部3を拡大して示すグラフである。図23~28においては、縦軸にセンサ出力電圧(V)、横軸に入力電流(A)を示している。
FIG. 23 is a graph showing a relationship between an input current value and a sensor output voltage in the current sensor according to the second embodiment. FIG. 24 is a graph showing an enlarged view of the vicinity 3 of the input current value in FIG. FIG. 25 is a graph showing the relationship between the input current value and the sensor output voltage in the current sensor according to Comparative Example 2. FIG. 26 is an enlarged graph showing the vicinity 3 of the input current value 0A in FIG. FIG. 27 is a graph showing the relationship between the input current value and the sensor output voltage in the current sensor according to Comparative Example 3. FIG. 28 is an enlarged graph showing the vicinity 3 of the input current value 0A in FIG. 23 to 28, the vertical axis represents the sensor output voltage (V), and the horizontal axis represents the input current (A).
図23~28に示すように、1次導体110を流れる入力電流を正負で掃引した際に、比較例2に係る電流センサ200および比較例3に係る電流センサ300の各々においては、入力電流値の0A近傍部3にてセンサ出力電圧に大きなずれが発生した。実施例2に係る電流センサ100においては、1次導体110を流れる入力電流を正負で掃引した際に、入力電流値の0A近傍部3にてセンサ出力電圧のずれは認められなかった。
As shown in FIGS. 23 to 28, when the input current flowing through the primary conductor 110 is swept positively and negatively, the current sensor 200 according to Comparative Example 2 and the current sensor 300 according to Comparative Example 3 each have an input current value. The sensor output voltage greatly deviated in the vicinity 3 of 0A. In the current sensor 100 according to Example 2, when the input current flowing through the primary conductor 110 was swept positively and negatively, no deviation in sensor output voltage was observed in the vicinity 3 of the input current value of 0A.
図29は、実施例2に係る電流センサ100、比較例2に係る電流センサ200、比較例3に係る電流センサ300、比較例4に係る電流センサの各々のヒステリシス率を示すグラフである。図29においては、縦軸にヒステリシス率(%FS)、横軸にサンプル名を示している。
FIG. 29 is a graph showing hysteresis rates of the current sensor 100 according to the second embodiment, the current sensor 200 according to the second comparative example, the current sensor 300 according to the third comparative example, and the current sensor according to the fourth comparative example. In FIG. 29, the vertical axis represents the hysteresis rate (% FS) and the horizontal axis represents the sample name.
比較例4に係る電流センサは、1対の磁性体部材が設けられていない点のみ実施例1に係る電流センサと異なる。ヒステリシス率とは、入力電流値が0Aである時のセンサ出力電圧の差の、入力電流値が±300Aである時のセンサ出力電圧に対する100分率である。
The current sensor according to Comparative Example 4 differs from the current sensor according to Example 1 only in that a pair of magnetic members is not provided. The hysteresis rate is a 100-minute ratio of the difference in sensor output voltage when the input current value is 0 A to the sensor output voltage when the input current value is ± 300 A.
図29に示すように、比較例2に係る電流センサ200および比較例3に係る電流センサ300の各々においては、1.8%以上のヒステリシス率を有するのに対して、実施例2に係る電流センサ100においては、ヒステリシス率が0.2%に低減され、1対の磁性体部材が設けられていない比較例4に係る電流センサのヒステリシス率である0.1%と略同等であった。
As shown in FIG. 29, each of the current sensor 200 according to the comparative example 2 and the current sensor 300 according to the comparative example 3 has a hysteresis rate of 1.8% or more, whereas the current according to the second example. In the sensor 100, the hysteresis rate was reduced to 0.2%, which was substantially the same as the hysteresis rate of 0.1% of the current sensor according to Comparative Example 4 in which the pair of magnetic members were not provided.
この実測結果から、実施例2に係る電流センサ100においては、1対の磁性体部材170を設けることによるヒステリシスの増加を抑制できることが確認できた。
From the actual measurement results, it was confirmed that in the current sensor 100 according to Example 2, an increase in hysteresis due to the provision of the pair of magnetic members 170 can be suppressed.
上記の検証結果からも確認された通り、本実施形態に係る電流センサ100においては、2つの空隙173の各々が、1次導体110を流れる電流が流れる方向(Y軸方向)から見て、1対の磁性体部材170が成す矩形形状の対角に位置していることにより、1対の磁性体部材170の残留磁化により発生する磁界による測定誤差を低減することができる。
As confirmed from the above verification results, in the current sensor 100 according to the present embodiment, each of the two air gaps 173 is 1 as viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). By being positioned at the diagonal of the rectangular shape formed by the pair of magnetic members 170, measurement errors due to the magnetic field generated by the residual magnetization of the pair of magnetic members 170 can be reduced.
また、本実施形態に係る電流センサ100においては、第1磁気センサ120aおよび第2磁気センサ120bの各々をロバスト領域内に位置させることにより、電流センサ100の組み立てに高い精度が要求されないため、電流センサ100を容易に製造可能である。
Further, in the current sensor 100 according to the present embodiment, since the first magnetic sensor 120a and the second magnetic sensor 120b are positioned in the robust region, high accuracy is not required for the assembly of the current sensor 100. The sensor 100 can be easily manufactured.
以下、本発明の実施形態2に係る電流センサについて説明する。なお、実施形態2に係る電流センサ400は、他の1対の磁性体部材をさらに備える点のみ実施形態1に係る電流センサと異なるため、他の構成については説明を繰り返さない。
Hereinafter, a current sensor according to Embodiment 2 of the present invention will be described. Note that the current sensor 400 according to the second embodiment is different from the current sensor according to the first embodiment only in that it further includes another pair of magnetic members, and thus the description of the other configurations will not be repeated.
(実施形態2)
図30は、本発明の実施形態2に係る電流センサの構成を示す断面図である。図30においては、図3と同様の方向から電流センサを見た断面視にて図示している。 (Embodiment 2)
FIG. 30 is a cross-sectional view showing a configuration of a current sensor according toEmbodiment 2 of the present invention. 30 is a cross-sectional view of the current sensor as viewed from the same direction as in FIG.
図30は、本発明の実施形態2に係る電流センサの構成を示す断面図である。図30においては、図3と同様の方向から電流センサを見た断面視にて図示している。 (Embodiment 2)
FIG. 30 is a cross-sectional view showing a configuration of a current sensor according to
図30に示すように、本発明の実施形態2に係る電流センサ400は、1次導体110を電流が流れる方向(Y軸方向)から見て、それぞれL字形状を有する他の1対の磁性体部材470をさらに備える。具体的には、他の1対の磁性体部材470は、第3磁性体部材471および第4磁性体部材472から構成されている。他の1対の磁性体部材470は、1次導体110を流れる電流が流れる方向(Y軸方向)から見て、互いの端部同士の間に空隙473が設けられた矩形形状を成し、1対の磁性体部材170に対して間隔を置いて1対の磁性体部材170の周りを囲んでいる。他の1対の磁性体部材470の空隙473は、1対の磁性体部材170の各々の角部171r,172rの外側に位置している。
As shown in FIG. 30, the current sensor 400 according to the second embodiment of the present invention includes another pair of magnetic elements each having an L shape when the primary conductor 110 is viewed from the direction in which the current flows (Y-axis direction). A body member 470 is further provided. Specifically, the other pair of magnetic members 470 is composed of a third magnetic member 471 and a fourth magnetic member 472. The other pair of magnetic members 470 has a rectangular shape in which a gap 473 is provided between the ends when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction), The pair of magnetic members 170 is surrounded by a distance from the pair of magnetic members 170. The gaps 473 of the other pair of magnetic members 470 are located outside the corners 171r and 172r of the pair of magnetic members 170, respectively.
第3磁性体部材471および第4磁性体部材472の各々は、第3板状部と、第3板状部に直交している第4板状部とを有している。第3磁性体部材471および第4磁性体部材472の各々の第3板状部と1次導体110とは、互いに平行に位置している。第3磁性体部材471の第3板状部と、第2磁性体部材172の第1板状部とは、互いに間隔を置いて平行に位置している。第4磁性体部材472の第3板状部と、第1磁性体部材171の各々の第1板状部とは、互いに間隔を置いて平行に位置している。
Each of the third magnetic member 471 and the fourth magnetic member 472 has a third plate-like portion and a fourth plate-like portion orthogonal to the third plate-like portion. The third plate-like portion of each of the third magnetic member 471 and the fourth magnetic member 472 and the primary conductor 110 are positioned in parallel to each other. The third plate-like portion of the third magnetic member 471 and the first plate-like portion of the second magnetic member 172 are located in parallel with a distance from each other. The third plate-like portion of the fourth magnetic body member 472 and each first plate-like portion of the first magnetic body member 171 are positioned in parallel with an interval therebetween.
第3磁性体部材471の第4板状部と、第1磁性体部材171の第2板状部とは、互いに間隔を置いて平行に位置している。第4磁性体部材472の第4板状部と、第2磁性体部材172の各々の第2板状部とは、互いに間隔を置いて平行に位置している。
The fourth plate-like portion of the third magnetic member 471 and the second plate-like portion of the first magnetic member 171 are located in parallel with a distance from each other. The fourth plate-like portion of the fourth magnetic body member 472 and each second plate-like portion of the second magnetic body member 172 are positioned in parallel with a space between each other.
2つの空隙473の各々は、1次導体110を電流が流れる方向(Y軸方向)において、他の1対の磁性体部材470の一端から他端まで延在している。2つの空隙473の各々は、1次導体110を流れる電流が流れる方向(Y軸方向)から見て、他の1対の磁性体部材470が成す矩形形状の対角に位置している。1次導体110を流れる電流が流れる方向(Y軸方向)から見て、他の1対の磁性体部材470が成す矩形形状の中心位置と、1次導体110の貫通孔110hの位置とは重なっている。
Each of the two gaps 473 extends from one end of the other pair of magnetic members 470 to the other end in the direction in which the current flows through the primary conductor 110 (Y-axis direction). Each of the two gaps 473 is located at a diagonal of a rectangular shape formed by the other pair of magnetic members 470 when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). When viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction), the center position of the rectangular shape formed by the other pair of magnetic members 470 overlaps the position of the through hole 110h of the primary conductor 110. ing.
第3磁性体部材471および第4磁性体部材472の各々は、パーマロイで構成されているが、第3磁性体部材471および第4磁性体部材472の各々の材料は、パーマロイに限られず、軟鉄鋼、ケイ素鋼、電磁鋼、ニッケル合金、鉄合金またはフェライトなどの、透磁率および飽和磁束密度の高い磁性体材料であればよい。
Each of the third magnetic member 471 and the fourth magnetic member 472 is made of permalloy, but the material of each of the third magnetic member 471 and the fourth magnetic member 472 is not limited to permalloy, and is soft. Any magnetic material having high magnetic permeability and saturation magnetic flux density, such as iron steel, silicon steel, electromagnetic steel, nickel alloy, iron alloy, or ferrite, may be used.
本実施形態においては、薄板をプレス加工することにより第3磁性体部材471および第4磁性体部材472の各々が形成されている。ただし、第3磁性体部材471および第4磁性体部材472の各々の形成方法はこれに限られず、切削または鋳造などの方法によって第3磁性体部材471および第4磁性体部材472の各々が形成されてもよい。
In the present embodiment, each of the third magnetic member 471 and the fourth magnetic member 472 is formed by pressing a thin plate. However, the formation method of each of the third magnetic member 471 and the fourth magnetic member 472 is not limited to this, and each of the third magnetic member 471 and the fourth magnetic member 472 is formed by a method such as cutting or casting. May be.
図30に示すように、本実施形態に係る電流センサ400においては、第1磁気センサ120aおよび第2磁気センサ120bの各々は、1対の磁性体部材170および他の1対の磁性体部材470によって周りを2重に囲まれているため、第1磁気センサ120aおよび第2磁気センサ120bの各々に誤差要因である外部磁界が到達することをさらに抑制できる。その結果、第1磁気センサ120aおよび第2磁気センサ120bの各々が、不要な外部磁界を検知しないようにすることができる。すなわち、1対の磁性体部材170および他の1対の磁性体部材470の各々が、磁気シールドとして機能する。
As shown in FIG. 30, in the current sensor 400 according to the present embodiment, each of the first magnetic sensor 120a and the second magnetic sensor 120b includes a pair of magnetic members 170 and another pair of magnetic members 470. Therefore, it is possible to further suppress the external magnetic field, which is an error factor, from reaching each of the first magnetic sensor 120a and the second magnetic sensor 120b. As a result, each of the first magnetic sensor 120a and the second magnetic sensor 120b can be prevented from detecting an unnecessary external magnetic field. That is, each of the pair of magnetic members 170 and the other pair of magnetic members 470 functions as a magnetic shield.
また、他の1対の磁性体部材470の空隙473が、1対の磁性体部材170の各々の角部171r,172rの外側に位置していることにより、第1磁気センサ120aおよび第2磁気センサ120bの周りを、1対の磁性体部材170および他の1対の磁性体部材470によって完全に囲むことができる。その結果、第1磁気センサ120aおよび第2磁気センサ120bの各々が、不要な外部磁界をより検知しないようにすることができる。
Further, the gaps 473 of the other pair of magnetic members 470 are positioned outside the corners 171r and 172r of the pair of magnetic members 170, so that the first magnetic sensor 120a and the second magnetic member 120a. The sensor 120b can be completely surrounded by a pair of magnetic members 170 and another pair of magnetic members 470. As a result, each of the first magnetic sensor 120a and the second magnetic sensor 120b can be prevented from detecting an unnecessary external magnetic field.
本実施形態に係る電流センサ400においても、2つの空隙173の各々が、1次導体110を流れる電流が流れる方向(Y軸方向)から見て、1対の磁性体部材170が成す矩形形状の対角に位置していることにより、1対の磁性体部材170の残留磁化により発生する磁界による測定誤差を低減することができる。
Also in the current sensor 400 according to the present embodiment, each of the two gaps 173 has a rectangular shape formed by the pair of magnetic members 170 when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). By being positioned diagonally, measurement errors due to the magnetic field generated by the residual magnetization of the pair of magnetic members 170 can be reduced.
以下、本発明の実施形態3に係る電流センサについて説明する。なお、実施形態3に係る電流センサ500は、1つのプリント基板に2つの磁気センサが実装されている点のみ実施形態2に係る電流センサと異なるため、他の構成については説明を繰り返さない。
Hereinafter, a current sensor according to Embodiment 3 of the present invention will be described. Note that the current sensor 500 according to the third embodiment is different from the current sensor according to the second embodiment only in that two magnetic sensors are mounted on one printed circuit board, and thus the description of the other configurations will not be repeated.
(実施形態3)
図31は、本発明の実施形態3に係る電流センサの構成を示す断面図である。図31においては、図3と同様の方向から電流センサを見た断面視にて図示している。図31に示すように、本発明の実施形態3に係る電流センサ500においては、プリント基板530cは、貫通孔530hに1次導体110を挿入された状態で保持される。すなわち、プリント基板530cは、1次導体110に垂直に位置している。 (Embodiment 3)
FIG. 31 is a cross-sectional view showing a configuration of a current sensor according toEmbodiment 3 of the present invention. In FIG. 31, it shows in the cross-sectional view which looked at the current sensor from the same direction as FIG. As shown in FIG. 31, in the current sensor 500 according to Embodiment 3 of the present invention, the printed circuit board 530c is held in a state where the primary conductor 110 is inserted into the through hole 530h. That is, the printed circuit board 530 c is positioned perpendicular to the primary conductor 110.
図31は、本発明の実施形態3に係る電流センサの構成を示す断面図である。図31においては、図3と同様の方向から電流センサを見た断面視にて図示している。図31に示すように、本発明の実施形態3に係る電流センサ500においては、プリント基板530cは、貫通孔530hに1次導体110を挿入された状態で保持される。すなわち、プリント基板530cは、1次導体110に垂直に位置している。 (Embodiment 3)
FIG. 31 is a cross-sectional view showing a configuration of a current sensor according to
第1磁気センサ120aおよび第2磁気センサ120bは、差動増幅器および受動素子と共にプリント基板530cに実装されている。なお、図31においては、差動増幅器および受動素子は図示していない。差動増幅器および受動素子は、第1磁気センサ120aおよび第2磁気センサ120bが実装されているプリント基板530cとは異なるプリント基板に、実装されていてもよい。
The first magnetic sensor 120a and the second magnetic sensor 120b are mounted on a printed circuit board 530c together with a differential amplifier and a passive element. In FIG. 31, the differential amplifier and the passive element are not shown. The differential amplifier and the passive element may be mounted on a printed board different from the printed board 530c on which the first magnetic sensor 120a and the second magnetic sensor 120b are mounted.
第1磁気センサ120aおよび第2磁気センサ120bは、貫通孔530hを挟んで互いに反対側に位置している。第1磁気センサ120aおよび第2磁気センサ120bの各々は、貫通孔530hに対して間隔を置いて位置している。プリント基板530cの貫通孔530hに1次導体110が挿入された状態において、第1磁気センサ120aは貫通孔530hの直上に位置し、第2プリント基板130bは貫通孔530hの直下に位置している。すなわち、第1磁気センサ120aと第2磁気センサ120bとは、1次導体110を挟んで互いに反対側に位置している。
The first magnetic sensor 120a and the second magnetic sensor 120b are located on opposite sides of the through hole 530h. Each of the first magnetic sensor 120a and the second magnetic sensor 120b is located at an interval from the through hole 530h. In a state where the primary conductor 110 is inserted into the through hole 530h of the printed circuit board 530c, the first magnetic sensor 120a is positioned directly above the through hole 530h, and the second printed circuit board 130b is positioned directly below the through hole 530h. . That is, the first magnetic sensor 120a and the second magnetic sensor 120b are located on opposite sides of the primary conductor 110.
本実施形態に係る電流センサ500においては、第1磁気センサ120aおよび第2磁気センサ120bの各々は、ロバスト領域内に位置している。すなわち、第1磁気センサ120aおよび第2磁気センサ120bがロバスト領域内に位置するように、第1磁気センサ120aおよび第2磁気センサ120bの各々と貫通孔530hとの間隔を適宜設定している。
In the current sensor 500 according to the present embodiment, each of the first magnetic sensor 120a and the second magnetic sensor 120b is located in the robust region. That is, the interval between each of the first magnetic sensor 120a and the second magnetic sensor 120b and the through hole 530h is appropriately set so that the first magnetic sensor 120a and the second magnetic sensor 120b are positioned in the robust region.
第1磁気センサ120aおよび第2磁気センサ120bの各々の検出軸の方向(感磁方向)は、1次導体110の幅方向(X軸方向)である。本実施形態に係る電流センサ500においても、第1磁気センサ120aおよび第2磁気センサ120bの各々に作用するX軸方向、Y軸方向およびZ軸方向の磁束密度を低減することができるため、第1磁気センサ120aおよび第2磁気センサ120bに加わる磁界の強度にばらつきが生ずることを抑制できる。その結果、電流センサ500によって被測定電流の大きさを安定して測定することができる。
The direction (magnetic direction) of the detection axis of each of the first magnetic sensor 120a and the second magnetic sensor 120b is the width direction (X-axis direction) of the primary conductor 110. Also in the current sensor 500 according to the present embodiment, the magnetic flux density in the X-axis direction, the Y-axis direction, and the Z-axis direction acting on each of the first magnetic sensor 120a and the second magnetic sensor 120b can be reduced. Variations in the strength of the magnetic field applied to the first magnetic sensor 120a and the second magnetic sensor 120b can be suppressed. As a result, the current sensor 500 can stably measure the magnitude of the current to be measured.
本実施形態に係る電流センサ500においても、2つの空隙173の各々が、1次導体110を流れる電流が流れる方向(Y軸方向)から見て、1対の磁性体部材170が成す矩形形状の対角に位置していることにより、1対の磁性体部材170の残留磁化により発生する磁界による測定誤差を低減することができる。
Also in the current sensor 500 according to the present embodiment, each of the two gaps 173 has a rectangular shape formed by the pair of magnetic members 170 when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). By being positioned diagonally, measurement errors due to the magnetic field generated by the residual magnetization of the pair of magnetic members 170 can be reduced.
また、他の1対の磁性体部材470の空隙473が、1対の磁性体部材170の各々の角部171r,172rの外側に位置していることにより、第1磁気センサ120aおよび第2磁気センサ120bの周りを、1対の磁性体部材170および他の1対の磁性体部材470によって完全に囲むことができる。その結果、第1磁気センサ120aおよび第2磁気センサ120bの各々が、不要な外部磁界をより検知しないようにすることができる。
Further, the gaps 473 of the other pair of magnetic members 470 are positioned outside the corners 171r and 172r of the pair of magnetic members 170, so that the first magnetic sensor 120a and the second magnetic member 120a. The sensor 120b can be completely surrounded by a pair of magnetic members 170 and another pair of magnetic members 470. As a result, each of the first magnetic sensor 120a and the second magnetic sensor 120b can be prevented from detecting an unnecessary external magnetic field.
以下、本発明の実施形態4に係る電流センサについて説明する。なお、実施形態4に係る電流センサ600は、プリント基板および磁性体部材が1次導体に対して付け外し可能に構成されている点のみ実施形態3に係る電流センサと異なるため、他の構成については説明を繰り返さない。
Hereinafter, a current sensor according to Embodiment 4 of the present invention will be described. The current sensor 600 according to the fourth embodiment differs from the current sensor according to the third embodiment only in that the printed circuit board and the magnetic member are configured to be detachable from the primary conductor. Will not repeat the description.
(実施形態4)
図32は、本発明の実施形態4に係る電流センサにおいて、プリント基板および磁性体部材を1次導体に対して取り付けた状態を示す断面図である。図33は、本発明の実施形態4に係る電流センサにおいて、プリント基板および磁性体部材を1次導体に対して取り付ける前の状態を示す断面図である。図32,33においては、図3と同様の方向から電流センサを見た断面視にて図示している。 (Embodiment 4)
FIG. 32 is a cross-sectional view showing a state where a printed circuit board and a magnetic member are attached to a primary conductor in a current sensor according toEmbodiment 4 of the present invention. FIG. 33 is a cross-sectional view illustrating a state before the printed circuit board and the magnetic member are attached to the primary conductor in the current sensor according to the fourth embodiment of the present invention. 32 and 33 are shown in a cross-sectional view of the current sensor as viewed from the same direction as in FIG.
図32は、本発明の実施形態4に係る電流センサにおいて、プリント基板および磁性体部材を1次導体に対して取り付けた状態を示す断面図である。図33は、本発明の実施形態4に係る電流センサにおいて、プリント基板および磁性体部材を1次導体に対して取り付ける前の状態を示す断面図である。図32,33においては、図3と同様の方向から電流センサを見た断面視にて図示している。 (Embodiment 4)
FIG. 32 is a cross-sectional view showing a state where a printed circuit board and a magnetic member are attached to a primary conductor in a current sensor according to
図31,32に示すように、本発明の実施形態4に係る電流センサ600においては、1対の磁性体部材170のうちの第1磁性体部材171、他の1対の磁性体部材470のうちの第3磁性体部材471、および、プリント基板630cが、樹脂または接着剤などからなる第1接合部材681により互いに接合されて一体になっている。1対の磁性体部材170のうちの第2磁性体部材172、および、他の1対の磁性体部材470のうちの第4磁性体部材472が、樹脂または接着剤などからなる第2接合部材682により互いに接合されて一体になっている。
As shown in FIGS. 31 and 32, in the current sensor 600 according to the fourth embodiment of the present invention, the first magnetic member 171 of the pair of magnetic members 170 and the other pair of magnetic members 470. The third magnetic body member 471 and the printed board 630c are joined together by a first joining member 681 made of resin or adhesive, and are integrated. The second magnetic member 172 of the pair of magnetic members 170 and the fourth magnetic member 472 of the other pair of magnetic members 470 are made of a resin or an adhesive. They are joined together by 682 and integrated.
具体的には、プリント基板630cの周面と第1磁性体部材171の内面とが、第1接合部材681により互いに接合されている。互いに対向している、第1磁性体部材171の第2板状部の外面と第3磁性体部材471の第4板状部の内面とが、第1接合部材681により互いに接合されている。互いに対向している、第2磁性体部材172の第2板状部の外面と第4磁性体部材472の第4板状部の内面とが、第2接合部材682により互いに接合されている。第1接合部材681および第2接合部材682の各々が樹脂で構成されている場合には、熱溶着により上記の部材同士が接合される。
Specifically, the peripheral surface of the printed circuit board 630c and the inner surface of the first magnetic member 171 are joined to each other by the first joining member 681. The outer surface of the second plate-like portion of the first magnetic member 171 and the inner surface of the fourth plate-like portion of the third magnetic member 471 facing each other are joined to each other by the first joining member 681. The outer surface of the second plate-like portion of the second magnetic member 172 and the inner surface of the fourth plate-like portion of the fourth magnetic member 472 facing each other are joined to each other by the second joining member 682. When each of the 1st joining member 681 and the 2nd joining member 682 is comprised with resin, said members are joined by heat welding.
プリント基板630cの周面のうち、第1磁性体部材171および第3磁性体部材471に囲まれていな端面側から、反対側の端面に向けて貫通溝630hが設けられている。プリント基板630cと第3磁性体部材471の第3板状部との間には、第2磁性体部材172の第1板状部が挿入可能な隙間が設けられている。
A through groove 630h is provided from the end surface side of the peripheral surface of the printed circuit board 630c that is not surrounded by the first magnetic member 171 and the third magnetic member 471 to the opposite end surface. A gap is provided between the printed board 630c and the third plate-like portion of the third magnetic member 471 so that the first plate-like portion of the second magnetic member 172 can be inserted.
プリント基板630c、1対の磁性体部材170および他の1対の磁性体部材470を1次導体110に対して取り付ける際には、プリント基板630cの貫通溝630hに1次導体110が挿入されるように、矢印61で示す方向にプリント基板630c、第1磁性体部材171および第3磁性体部材471を1次導体110に対して接近させる。また、プリント基板630cと第3磁性体部材471の第3板状部との間の隙間に第2磁性体部材172の第1板状部が挿入されるように、矢印62で示す方向に第2磁性体部材172および第4磁性体部材472を1次導体110に対して接近させる。
When the printed board 630c, the pair of magnetic members 170, and the other pair of magnetic members 470 are attached to the primary conductor 110, the primary conductor 110 is inserted into the through groove 630h of the printed board 630c. As described above, the printed circuit board 630 c, the first magnetic member 171, and the third magnetic member 471 are moved closer to the primary conductor 110 in the direction indicated by the arrow 61. Further, the first plate-like portion of the second magnetic member 172 is inserted in the direction indicated by the arrow 62 so that the first plate-like portion of the second magnetic member 172 is inserted into the gap between the printed circuit board 630c and the third plate-like portion of the third magnetic member 471. The second magnetic member 172 and the fourth magnetic member 472 are brought closer to the primary conductor 110.
図32に示すように、プリント基板630cおよび磁性体部材を1次導体110に対して取り付けた状態においては、プリント基板630cは、貫通溝630hに1次導体110を挿入された状態で保持される。すなわち、プリント基板630cは、1次導体110に垂直に位置している。
As shown in FIG. 32, when the printed circuit board 630c and the magnetic member are attached to the primary conductor 110, the printed circuit board 630c is held with the primary conductor 110 inserted in the through groove 630h. . That is, the printed circuit board 630 c is positioned perpendicular to the primary conductor 110.
本実施形態においては、2つの空隙173および2つの空隙473の各々は、第1接合部材681および第2接合部材682の少なくとも一方によって埋められている。本実施形態に係る電流センサ600においては、プリント基板630cおよび磁性体部材が1次導体110に対して付け外し可能に構成されているため、電流センサ600の組み立ておよび分解が容易である。
In the present embodiment, each of the two gaps 173 and the two gaps 473 is filled with at least one of the first joining member 681 and the second joining member 682. In the current sensor 600 according to the present embodiment, the printed circuit board 630c and the magnetic member are configured to be detachable from the primary conductor 110, so that the assembly and disassembly of the current sensor 600 is easy.
本実施形態に係る電流センサ600においても、2つの空隙173の各々が、1次導体110を流れる電流が流れる方向(Y軸方向)から見て、1対の磁性体部材170が成す矩形形状の対角に位置していることにより、1対の磁性体部材170の残留磁化により発生する磁界による測定誤差を低減することができる。
Also in the current sensor 600 according to the present embodiment, each of the two gaps 173 has a rectangular shape formed by a pair of magnetic members 170 when viewed from the direction in which the current flowing through the primary conductor 110 flows (Y-axis direction). By being positioned diagonally, measurement errors due to a magnetic field generated by the residual magnetization of the pair of magnetic members 170 can be reduced.
また、他の1対の磁性体部材470の空隙473が、1対の磁性体部材170の各々の角部171r,172rの外側に位置していることにより、第1磁気センサ120aおよび第2磁気センサ120bの周りを、1対の磁性体部材170および他の1対の磁性体部材470によって完全に囲むことができる。その結果、第1磁気センサ120aおよび第2磁気センサ120bの各々が、不要な外部磁界をより検知しないようにすることができる。
Further, the gaps 473 of the other pair of magnetic members 470 are positioned outside the corners 171r and 172r of the pair of magnetic members 170, so that the first magnetic sensor 120a and the second magnetic member 120a. The sensor 120b can be completely surrounded by a pair of magnetic members 170 and another pair of magnetic members 470. As a result, each of the first magnetic sensor 120a and the second magnetic sensor 120b can be prevented from detecting an unnecessary external magnetic field.
今回開示された実施形態および実施例はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。
The embodiments and examples disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
1 基準線、3 近傍部、10 電流、100,200,300,400,500,600 電流センサ、110 1次導体、110e 磁界、110h,530h 貫通孔、110s 表面、110t 裏面、120a 第1磁気センサ、120b 第2磁気センサ、121 配置位置、130a 第1プリント基板、130b 第2プリント基板、140a 第1オペアンプ、140b 第2オペアンプ、150a 第1受動素子、150b 第2受動素子、160a 第1回路基板、160b 第2回路基板、170,270,370,470 1対の磁性体部材、171,271,371 第1磁性体部材、172,272,372 第2磁性体部材、171r,172r 角部、173,273,373,473 空隙、190 算出部、471 第3磁性体部材、472 第4磁性体部材、530c,630c プリント基板、630h 貫通溝、681 第1接合部材、682 第2接合部材、Bx,By,Bz 規格化磁束密度、LX,LZ,RX,RZ 磁束密度、O 中心位置、T1 第1領域、T2 第2領域。
1 reference line, 3 neighbors, 10 current, 100, 200, 300, 400, 500, 600 current sensor, 110 primary conductor, 110e magnetic field, 110h, 530h through hole, 110s surface, 110t back surface, 120a first magnetic sensor , 120b second magnetic sensor, 121 arrangement position, 130a first printed circuit board, 130b second printed circuit board, 140a first operational amplifier, 140b second operational amplifier, 150a first passive element, 150b second passive element, 160a first circuit board , 160b Second circuit board, 170, 270, 370, 470 One pair of magnetic members, 171, 271, 371 First magnetic member, 172, 272, 372 Second magnetic member, 171r, 172r Corner, 173 , 273, 373, 473 gap, 190 calculation unit, 471 third magnetic body member, 47 Fourth magnetic member, 530c, 630c Printed circuit board, 630h Through groove, 681 First joint member, 682 Second joint member, Bx, By, Bz Normalized magnetic flux density, LX, LZ, RX, RZ magnetic flux density, O center Position, T 1 first region, T 2 second region.
Claims (7)
- 測定対象の電流が流れる1次導体と、
前記1次導体を流れる前記電流により発生する磁界の強さを検出する少なくとも1つの磁気センサと、
前記電流が流れる方向から見て、それぞれL字形状を有する1対の磁性体部材とを備え、
前記1対の磁性体部材は、前記電流が流れる方向から見て、互いの端部同士の間に空隙が設けられた矩形形状を成し、前記1次導体および前記磁気センサの周りを囲んでいる、電流センサ。 A primary conductor through which the current to be measured flows;
At least one magnetic sensor for detecting the strength of a magnetic field generated by the current flowing through the primary conductor;
A pair of magnetic members each having an L shape when viewed from the direction in which the current flows,
The pair of magnetic members has a rectangular shape with a gap provided between the ends when viewed from the direction in which the current flows, and surrounds the primary conductor and the magnetic sensor. A current sensor. - 前記1次導体は、平板形状を有し、
前記磁気センサは、前記1次導体の厚さ方向および前記電流が流れる方向の両方と直交する方向の磁界を検出可能とされている、請求項1に記載の電流センサ。 The primary conductor has a flat plate shape,
The current sensor according to claim 1, wherein the magnetic sensor is capable of detecting a magnetic field in a direction orthogonal to both a thickness direction of the primary conductor and a direction in which the current flows. - 前記磁気センサは、前記1次導体の幅方向における中央部の、前記1次導体の厚さ方向における一方側および他方側の少なくとも一方に配置されている、請求項1または2に記載の電流センサ。 3. The current sensor according to claim 1, wherein the magnetic sensor is disposed on at least one of one side and the other side in the thickness direction of the primary conductor at a central portion in the width direction of the primary conductor. .
- 前記磁気センサとして第1磁気センサと第2磁気センサとを備え、
前記第1磁気センサと前記第2磁気センサとは、前記1次導体を挟んで互いに対向して位置している、請求項1から3のいずれか1項に記載の電流センサ。 A first magnetic sensor and a second magnetic sensor as the magnetic sensor;
4. The current sensor according to claim 1, wherein the first magnetic sensor and the second magnetic sensor are positioned to face each other across the primary conductor. 5. - 前記第1磁気センサの検出値と前記第2磁気センサの検出値とを演算することにより前記電流の値を算出する算出部をさらに備え、
前記1次導体を流れる前記電流により発生する磁界の強さについて、前記第1磁気センサの検出値の位相と前記第2磁気センサの検出値の位相とが逆相であり、
前記算出部が減算器または差動増幅器である、請求項4に記載の電流センサ。 A calculation unit that calculates a value of the current by calculating a detection value of the first magnetic sensor and a detection value of the second magnetic sensor;
Regarding the strength of the magnetic field generated by the current flowing through the primary conductor, the phase of the detection value of the first magnetic sensor and the phase of the detection value of the second magnetic sensor are in reverse phase,
The current sensor according to claim 4, wherein the calculation unit is a subtractor or a differential amplifier. - 前記第1磁気センサの検出値と前記第2磁気センサの検出値とを演算することにより前記電流の値を算出する算出部をさらに備え、
前記1次導体を流れる前記電流により発生する磁界の強さについて、前記第1磁気センサの検出値の位相と前記第2磁気センサの検出値の位相とが同相であり、
前記算出部が加算器または加算増幅器である、請求項4に記載の電流センサ。 A calculation unit that calculates a value of the current by calculating a detection value of the first magnetic sensor and a detection value of the second magnetic sensor;
Regarding the strength of the magnetic field generated by the current flowing through the primary conductor, the phase of the detection value of the first magnetic sensor and the phase of the detection value of the second magnetic sensor are in phase,
The current sensor according to claim 4, wherein the calculation unit is an adder or an addition amplifier. - 前記電流が流れる方向から見て、それぞれL字形状を有する他の1対の磁性体部材とをさらに備え、
前記他の1対の磁性体部材は、前記電流が流れる方向から見て、互いの端部同士の間に空隙が設けられた矩形形状を成し、前記1対の磁性体部材に対して間隔を置いて前記1対の磁性体部材の周りを囲み、
前記他の1対の磁性体部材の空隙は、前記1対の磁性体部材の各々の角部の外側に位置している、請求項1から6のいずれか1項に記載の電流センサ。 Another pair of magnetic members each having an L-shape when viewed from the direction in which the current flows,
The other pair of magnetic members has a rectangular shape in which a gap is provided between the ends when viewed from the direction in which the current flows, and is spaced from the pair of magnetic members. To surround the pair of magnetic members,
The current sensor according to any one of claims 1 to 6, wherein the gap between the other pair of magnetic members is located outside a corner of each of the pair of magnetic members.
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