JP-7856790-B2 - Current sensor

Inventors

• 田村 学
• 高野 秀昭
• 植田 千亜紀
• 熊谷 優

Assignees

• アルプスアルパイン株式会社

Dates

Publication Date

20260511

Application Date

20231002

Priority Date

20221212

Claims (12)

1. A core member having a first gap sandwiched between end faces, formed in an annular shape through which a busbar can be inserted, and which collects the magnetic field generated when the current to be measured flows through the busbar, A magnetic detection unit capable of detecting the magnetic field collected by the core member, A current sensor comprising a substrate on which the magnetic detection unit is planar mounted on one side , The magnetic detection unit has a detection surface for detecting the magnetic field, and is capable of detecting magnetic field components parallel to the detection surface. The detection surface is arranged such that it is parallel to the direction in which the two end faces that form the first gap face each other. The magnetic detection unit is located outside the first gap. When viewed from a direction perpendicular to the detection surface, it is arranged to overlap with the first gap, The plate surface of the substrate and the end surface of the core member are perpendicular to each other. The substrate has a grounding surface provided along a surface parallel to the one surface, in addition to the one surface. A current sensor characterized in that the grounded substrate is placed between the ungrounded core member and the magnetic detection unit, so that the solid surface acts as a shield .
2. The current sensor according to claim 1 , wherein the substrate and the core member are locked together.
3. The current sensor according to claim 1, wherein the core member has a second gap at a position different from the first gap.
4. The housing includes the magnetic detection unit and the core member, The housing has a busbar through hole through which the busbar can be inserted, The busbar through-hole is provided penetrating the inside of the ring formed by the core member, The current sensor according to claim 1, wherein the cross-sectional shape of the busbar through-hole is such that the first clearance width in the direction in which the two end faces forming the first gap face each other is greater than the second clearance width in the direction perpendicular to the direction in which the two end faces face each other.
5. The busbar has the aforementioned current to be measured and is capable of carrying the current, The current sensor according to claim 1, wherein the busbar is positioned to penetrate the inside of the ring formed by the core member, and the sensor has a housing that integrally holds the magnetic detection unit, the core member, and the busbar.
6. When viewed along the direction of the central axis of the ring of the core member, The magnetic detection unit is positioned at a location offset from the straight line passing through the centers of the two end faces that form the first gap. The current sensor according to claim 1, wherein at least a portion of the magnetic detection unit is arranged to overlap with the first gap.
7. The current sensor according to claim 1, wherein the detection element of the magnetic detection unit is a magnetoresistive element.
8. When viewed from a direction perpendicular to the direction in which the end faces forming the first gap in the detection surface are facing each other, The magnetic detection unit is positioned relative to the first gap in a direction along the central axis of the ring of the core member. When viewed from a direction along the central axis of the ring of the core member, The current sensor according to claim 1 , wherein the magnetic detection unit is arranged to overlap with the first gap.
9. The current sensor according to claim 1 , wherein a sub-magnetic detection unit is disposed on the surface of the substrate opposite to the surface on which the magnetic detection unit is disposed.
10. The current sensor according to claim 9 , wherein the detection element of the sub-magnetic detection unit is a magnetoresistive element and is located outside the first gap of the core member.
11. The detection element of the magnetic detection unit is a magnetoresistive element. The detection element of the sub-magnetic detection unit is a Hall sensor, The current sensor according to claim 9 , wherein the Hall sensor is disposed within the first gap of the core member.
12. A core member having a first gap sandwiched between end faces, formed in an annular shape through which a busbar can be inserted, and which collects the magnetic field generated when the current to be measured flows through the busbar, A magnetic detection unit capable of detecting the magnetic field collected by the core member, In a current sensor equipped with, The magnetic detection unit has a detection surface for detecting the magnetic field, and is capable of detecting magnetic field components parallel to the detection surface. The detection surface is arranged such that it is parallel to the direction in which the two end faces that form the first gap face each other. The magnetic detection unit is located outside the first gap. When viewed from a direction perpendicular to the detection surface, it is arranged to overlap with the first gap, When viewed along the direction of the central axis of the ring of the core member, The magnetic detection unit is positioned at a location offset away from the busbar with respect to a straight line passing through the centers of the two end faces that form the first gap. The current sensor according to claim 1, wherein at least a portion of the magnetic detection unit is arranged to overlap with the first gap.

Description

This invention relates to a current sensor that detects a magnetic field generated by a current flowing through a conductor and measures the current value of the current from the detected magnetic field. In recent years, current sensors have been used to control and monitor various devices by attaching them to the devices to measure the current flowing through them. Among these types of current sensors, there are known current sensors that use magnetoelectric conversion elements to sense the magnetic field generated by the current flowing through the current path. Furthermore, there are also known current sensors in which a core member surrounds the current path to facilitate magnetic field detection, and a Hall element, acting as a magnetoelectric conversion element, is placed within the gap of the core member. Patent Document 1 describes a current detection device comprising a magnetic core and a Hall element, for the purpose of avoiding current detection errors caused by pressure applied to the magnetic core, etc. Patent Document 2 describes a current detection device that aims to achieve both miniaturization of the magnetic core and suppression of deterioration of detection accuracy caused by noise magnetic field lines, comprising a magnetic core formed in a series with both ends facing each other via a gap and surrounding the perimeter of a hollow portion, and a Hall element placed in the gap to detect the magnetic flux that changes in accordance with the current passing through the hollow portion. Japanese Patent Publication No. 2013-142579Japanese Patent Publication No. 2012-247197 This is a front view of the current sensor according to the first embodiment.This is a side view of the current sensor according to the first embodiment.This is a perspective view of the core of a modified current sensor.This is a front view of a current sensor relating to another modified example.This is a disassembled perspective view of a current sensor.This is a front view of a current sensor relating to another modified example.Figure 5A is a cross-sectional view showing an enlarged view of the busbar and busbar through-hole in the current sensor.This graph shows the effect of busbar displacement on sensitivity in the modified current sensor shown in Figure 5A.This is a front view of a current sensor relating to another modified example.This is a magnified cross-sectional view of the busbar and busbar through-hole in the current sensor shown in Figure 7A.This is a front view of a current sensor relating to another modified example.This is a front view showing the temperature of the core member and the first gap when the busbar is energized, indicated by shades of gray.This is a front view of the current sensor according to the second embodiment.This is a side view of the current sensor according to the second embodiment.This is a side view and graph illustrating the relationship between the position of the magnetic sensing element in a current sensor and the magnetic flux density.This vector diagram shows the simulation results of the magnetic fields generated in the energized phase and adjacent phases by the current flowing through the energized phase busbar.This is a front view of a modified current sensor.This is a side view of a modified current sensor.This is a side view of a current sensor relating to another modified example.This is a side view of a current sensor relating to another modified example.This is a front view of a conventional current sensor.This is a side view of a conventional current sensor. The embodiments of the present invention will be described below with reference to the accompanying drawings. In each drawing, the same components are numbered the same and their descriptions are omitted. Reference coordinates are shown in each figure as appropriate to indicate the positional relationship of each component. The reference coordinates are defined as follows: the X direction is the direction in which the end faces defining the first gap of the core component face each other; the Y direction is the direction perpendicular to the X direction at the detection surface of the magnetic detection unit; and the Z direction is the direction of the central axis of the ring of the core component. [First Embodiment] Figures 1A and 1B are a front view and a side view of the current sensor 1 according to this embodiment. The current sensor 1 comprises a core member 2 and a magnetic detection unit 3. The core member 2 is made of a magnetic material and has a first gap 22 sandwiched between its end faces 21, and is formed in an annular shape through which the busbar 4 can be inserted. When the current to be measured flows through the busbar 4, the magnetic field generated from the busbar 4 is collected between the first gap 22, and the magnetic field between the first gap 22 is detected by the magnetic detection unit 3. In the following embodiments, the configuration in which the busbar 4 is inserted through th