JP2015132516A - Electric current detection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric current detection structure capable of accurately detecting electric current flowing in a bus bar.SOLUTION: An electric current detection structure includes: a bus bar 2 for flowing electric current in a longitudinal direction; and a magnetic detection element 3 for measuring the intensity of a magnetic field generated by electric current flowing in the bus bar 2. The electric current detection structure includes, in the bus bar 2, an electric current bypass 4 that is formed on the same plane as the bus bar 2 and connects two places of the bus bar 2 in longitudinal directions. The magnetic detection element 3 is arranged near the electric current bypass 4 so as to allow its detection axis D to be in the longitudinal direction of the bus bar 2.

Description

  The present invention relates to a current detection structure.

  2. Description of the Related Art Conventionally, when detecting a current flowing through a bus bar, the intensity of a magnetic field generated by a current to be detected is detected by a magnetic detection element. By detecting the strength of the magnetic field by the magnetic detection element, the current flowing through the bus bar can be obtained by calculation based on the strength of the magnetic field.

  As magnetic detection elements, MR (Magneto Resistance) sensors and GMR (Giant Magneto Resistive effect) sensors are known.

  In addition, there exists patent document 1 as prior art document information relevant to invention of this application.

Japanese Patent No. 5153481

  However, in the above-described conventional current detection structure, for example, when detecting a current flowing through each phase of a three-phase motor, the magnetic detection element is affected by a magnetic field generated by a current flowing through a bus bar other than the detection target. There is a problem that it is difficult to accurately detect the current flowing through the detection target bus bar.

  Therefore, an object of the present invention is to solve the above-described problems and provide a current detection structure that can accurately detect a current flowing through a bus bar.

  The present invention has been devised to achieve the above object, and includes a bus bar for passing a current along the longitudinal direction, and a magnetic detection element for measuring the strength of a magnetic field generated by the current flowing through the bus bar. A current detection structure, which is formed on the same plane as the bus bar, forms a current bypass circuit in the bus bar that connects two locations in the longitudinal direction of the bus bar, and the magnetic detection element is located in the vicinity of the current bypass circuit And a current detection structure in which the detection axis is arranged along the longitudinal direction of the bus bar.

  The magnetic detection element may be a GMR sensor.

  The current bypass may be formed to protrude laterally from one side of the bus bar.

  A notch that opens to the side of the bus bar may be formed, and the current bypass may be formed in the notch.

  The current bypass may be formed so as to be within the width of the bus bar.

  ADVANTAGE OF THE INVENTION According to this invention, the electric current detection structure which can detect the electric current which flows into a bus bar accurately can be provided.

It is a figure which shows the electric current detection structure which concerns on one Embodiment of this invention, (a) is a top view, (b) is a perspective view. It is a figure explaining the principle of the current detection structure of FIG. It is a top view which shows the example of application to the three-phase current path of the current detection structure of FIG. It is a top view which shows the electric current detection structure which concerns on one modification of this invention. It is a top view which shows the electric current detection structure which concerns on one modification of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1A and 1B are diagrams showing a current detection structure according to the present embodiment, in which FIG. 1A is a plan view and FIG. 1B is a perspective view.

  As shown in FIGS. 1A and 1B, the current detection structure 1 includes a bus bar 2 that flows current along the longitudinal direction, and a magnetic detection element 3 that measures the strength of a magnetic field generated by the current flowing through the bus bar 2. And.

  The bus bar 2 is a plate-like conductor and serves as a current path through which a current flows. As the magnetic detection element 3, a GMR sensor having a detection axis D in a direction perpendicular to the height direction of the element and having high sensitivity is used.

  In the current detection structure 1 according to the present embodiment, the current bypass circuit 4 that is formed on the same plane as the bus bar 2 and connects two locations in the longitudinal direction of the bus bar 2 is formed in the bus bar 2, and the magnetic detection element 3 is provided. In the vicinity of the current bypass 4, the detection axis D is arranged along the longitudinal direction of the bus bar 2.

  The current bypass 4 is formed integrally with the bus bar 2 so as to protrude from one side of the bus bar 2 to the side. Here, a U-shaped current bypass 4 that is reversed left and right in plan view is formed.

  As shown in FIG. 2, by forming the current bypass 4, a current flows through the current bypass 4, and a component in the width direction (X direction in the drawing) is generated in the current. As a result, a magnetic field having a component in the longitudinal direction (Y direction in the figure) of the bus bar 2 is generated due to the current width component. In the current detection structure 1, the magnetic detection element 3 measures the strength By of the magnetic field in the longitudinal direction of the bus bar 2 generated by forming the current bypass 4.

  The strength By of the magnetic field in the longitudinal direction of the bus bar 2 generated by the current bypass 4 is preferably as small as possible in order to suppress the influence on the surroundings. Therefore, it is desirable to arrange the magnetic detection element 3 as close as possible to the current bypass 4 in order to detect a small magnetic field strength By. In the present embodiment, the magnetic detection element 3 is arranged at a position overlapping the current bypass 4 in plan view, more specifically at a position overlapping a side extending in the width direction of the current bypass 4.

  In this embodiment, since a GMR sensor is used as the magnetic detection element 3, a small magnetic field can be detected. Further, since the GMR sensor has a detection axis D in a direction perpendicular to the height direction of the element, magnetic detection is performed in parallel with the bus bar 2 (so that the height direction of the element is the thickness direction of the bus bar 2). The element 3 can be disposed, and the entire current detection structure 1 can be reduced in thickness. Although not shown in FIG. 1, the magnetic detection element 3 is actually supported by the bus bar 2 and its surrounding members by a support member.

  In the current detection structure 1, the magnitude of the current flowing through the current bypass 4 is adjusted by adjusting the width of the current bypass 4, and the strength of the magnetic field generated in the longitudinal direction of the bus bar 2, that is, the magnetic detection element 3. It is possible to easily adjust the strength of the magnetic field detected by. In the current detection structure 1, it is necessary to design the magnetic detection element 3 so as to detect a magnetic field having an appropriate intensity according to the sensitivity of the magnetic detection element 3. Such a design is relatively easy. The current bypass 4 needs to be at least partially formed in a direction intersecting the longitudinal direction of the bus bar 2 but is formed so as to protrude from one side of the bus bar 2. Thus, it naturally becomes such a shape.

  By the way, when detecting the current flowing through each phase of a three-phase motor, for example, in order to measure the magnetic field formed by the entire current flowing through the bus bar 2, the GMR sensor is too sensitive, Since it becomes easy to be affected by the magnetic field due to the flowing current, it is difficult to perform the measurement as it is. In the present embodiment, by adjusting the width of the current bypass 4 or the like, the magnetic field strength suitable for measurement by the GMR sensor is adjusted, and the magnetic field strength in the longitudinal direction of the bus bar 2 is measured. By configuring, the influence of the current flowing through the surrounding bus bar 2 is suppressed, thereby enabling measurement even when a highly sensitive GMR sensor is used as the magnetic detection element 3.

  As shown in FIG. 3, the current detection structure 1 is used, for example, when measuring the current of each of three phases. The three bus bars 2 that form the current paths of the three phases are arranged to be spaced apart from each other in the width direction, current bypass circuits 4 are formed in the respective bus bars 2, and the magnetic detection elements 3 are arranged. Yes. The magnetic field in the longitudinal direction of the bus bar 2 generated by forming the current bypass 4 in each bus bar 2 does not interfere with each other, and each magnetic detection element 3 is affected by the magnetic field generated by the current of the other bus bar 2. I do not receive it.

  In FIG. 3, the current bypass 4 is formed on the same side in the width direction of each bus bar 2 (the left side in the drawing), but the current bypass 4 may be formed on a different side in any bus bar 2. . In that case, for example, if the bus bar 2 with the current bypass 4 formed on the right side of the drawing and the bus bar 2 with the current bypass 4 formed on the left side of the drawing are arranged adjacent to each other, the distance between the two magnetic detection elements 3 becomes short. It is also possible to support the magnetic detection element 3 using a common support member. However, mutual interference may occur if the current bypasses 4 are too close together. From the viewpoint of avoiding mutual interference, the current bypasses 4 should be formed on the same side in the width direction in all the bus bars 2. Is desirable.

  As described above, in the current detection structure 1 according to this embodiment, the current bypass circuit 4 that is formed on the same plane as the bus bar 2 and connects two locations in the longitudinal direction of the bus bar is formed in the bus bar 2, thereby detecting the magnetic field. The element 3 is disposed in the vicinity of the current bypass 4, and the detection axis D is disposed along the longitudinal direction of the bus bar 2.

  With such a configuration, it is difficult to be affected by the magnetic field generated by the current flowing through the bus bar 2 other than the detection target, and the current flowing through the detection target bus bar 2 can be accurately detected.

  Further, by adjusting the width of the current bypass 4 or the like, it is possible to generate a magnetic field having an appropriate intensity according to the sensitivity of the magnetic detection element 3, and a highly sensitive GMR sensor is used as the magnetic detection element 3. It becomes possible. Since the GMR sensor has a detection axis D in a direction perpendicular to the height direction of the element, the magnetic detection element 3 can be arranged in parallel with the bus bar 2 and contributes to the thinning of the current detection structure 1. To do.

  The present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the case where the U-shaped current bypass circuit 4 reversed left and right in plan view has been described. However, the present invention is not limited to this, and an arc shape like the current detection structure 41 illustrated in FIG. The current bypass 4 may be formed, and the shape of the current bypass 4 is not particularly limited. A plurality of current bypass circuits 4 may be formed.

  Furthermore, in the above-described embodiment, the case where the current bypass 4 is formed so as to protrude from one side of the bus bar 2 has been described. However, like the current detection structure 51 illustrated in FIG. A notch 52 may be formed in the notch 52, and the current bypass 4 may be formed in the notch 52.

  With this configuration, it is possible to form the current bypass 4 so as to be within the width of the bus bar 2, reduce the space for installing the bus bar 2, and realize a small current detection structure 51. it can.

  In the current detection structure 51, the magnetic detection element 3 can also be arranged so as to be within the width of the bus bar 2 in a top view, so that the effect of miniaturization is great.

DESCRIPTION OF SYMBOLS 1 Current detection structure 2 Bus bar 3 Magnetic detection element 4 Current bypass

Claims (5)

A current detection structure comprising a bus bar for passing a current along the longitudinal direction, and a magnetic detection element for measuring the strength of a magnetic field generated by the current flowing through the bus bar,
Formed on the same plane as the bus bar, forming a current bypass on the bus bar that connects two locations in the longitudinal direction of the bus bar,
The magnetic detection element is arranged in the vicinity of the current bypass, and the detection axis is arranged along the longitudinal direction of the bus bar. The current detection structure according to claim 1, wherein the magnetic detection element is a GMR sensor. The current detection structure according to claim 1, wherein the current bypass is formed to protrude from one side of the bus bar to the side. The current detection structure according to claim 1, wherein a notch that opens to a side of the bus bar is formed, and the current bypass is formed in the notch. The current detection structure according to claim 4, wherein the current bypass is formed so as to be within a width of the bus bar.

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