Current sensor

A current sensor and primary current technology, which is applied in the direction of inductors, fixed inductors, inductors/transformers/magnets, etc., can solve the problems of large-scale core shape, enlarged device structure, and inability to form a small current sensor, etc., to achieve Effect of suppressing magnetic flux saturation

Active Publication Date: 2009-10-21
MITSUBISHI ELECTRIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] As mentioned above, in the conventional current sensor, when measuring a large current, it is necessary to provide a separate feedback circuit in order to suppress the saturation of the magnetic flux in the core, and there is a problem that the device structure increases.
In addition, as a method of suppressing magnetic flux saturation in the core, there is also a method of increasing the cross-sectional area of ​​the core as described above, but there is a problem that the shape of the core becomes larger and a small current sensor cannot be configured.
[0010] Furthermore, as a countermeasure against magnetic flux saturation, there is a method of dividing the core as described above, but the reluctance in the gap part of the division is extremely high, and leakage flux occurs. As a result, the magnetic flux density around the core Reduced uniformity
Therefore, there is a problem that the measurement accuracy of the current sensor decreases.
[0011] In addition, in the method disclosed in the above-mentioned Patent Document 3 by using a mixture of magnetic powder and non-magnetic powder in the magnetic core to relax the saturation of the relative magnetic permeability of the magnetic core, the relative magnetic permeability with respect to the magnetic field changes, So there is such a problem that the sensitivity changes when the above magnetic core is applied to the current sensor

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Embodiment approach 1

[0052] refer to Figure 1 ~ Figure 3 , Figure 4A ,as well as Figure 4B The current sensor 101 according to Embodiment 1 of the present invention will be described. Such as figure 1 As shown, the current sensor 101 includes a core 1 and a secondary winding 2 .

[0053] In this embodiment, the core part 1 has a trunk part 1a formed by cutting a pipe into an annular shape, and a through-hole formed in a central part 1b. The trunk portion 1a has a peripheral surface 1a-1 and upper and lower surfaces 1a-2. In the present embodiment, the upper and lower surfaces 1a-2 each form a flat surface, but a convex shape such as a semicircle may also be used. In the through hole, the primary conductor 5 through which the primary current as the current to be measured flows is arranged along the central portion 1b, that is, the penetrating core portion 1 .

[0054] The core 1 further has: a plurality of magnetic body parts 3 composed of a magnetic body that divides the core part 1 in th...

Embodiment approach 2

[0074] Next, refer to Figure 10 The current sensor 106 according to Embodiment 2 of the present invention will be described. In addition, in Figure 10 In FIG. 2 , only the core part constituting the current sensor 106 is shown, and the illustration of the secondary winding 2 is omitted.

[0075]In Embodiment 1 described above, the core portion 1 is constituted by one structure in which the magnetic body portion 3 and the non-magnetic body portion 4 are integrally formed. In contrast, in the current sensor 106 according to Embodiment 2, the core 1 includes a plurality of divided cores 21 and 22 , here two. Embodiment 1 differs from Embodiment 2 in this point. By combining a plurality of split cores to form one core 1, an arbitrary distribution of sensitivity coefficients can be obtained as a characteristic of the current sensor. The description above in Embodiment 1 is applicable to other configurations and modified examples of the current sensor 106 , so those descriptio...

Embodiment approach 3

[0097] Next, refer to Figure 14 as well as Figure 15 A current sensor according to Embodiment 3 of the present invention will be described. In this embodiment, the current sensor described in Embodiments 1 and 2 above is fabricated on a plated or printed wiring board having excellent shape controllability.

[0098] Figure 14 as well as Figure 15 The current sensor 107 of this embodiment is shown to be figure 1 The current sensor 101 shown is fabricated on a substrate. Of course, the forms of the above-mentioned current sensors 102 to 106 may also be fabricated on the structure described below.

[0099] The current sensor 107 includes a first winding pattern substrate 9-1, a second winding pattern substrate 9-2, and a core pattern substrate 12 sandwiched between these winding pattern substrates 9-1, 9-2. The first winding pattern substrate 9-1 is a substrate made of a non-magnetic material such as a printed wiring board, and in this example, the above-mentioned conduc...

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Abstract

The invention provides a current sensor, which is indicated that a core (1) is divided by alternately arranging plural magnetic material portions (3) and plural non-magnetic material portions (4) in a circumferential direction of the core through which a primary conductor penetrates (5), a conductor is wound around the core under conditions in which each core cross section of the core (1) intersects the magnetic material portion and the non-magnetic material portion, each core cross section including a cut end surface of each conductor (2a) of a secondary winding wound (2) around the core (1), and a ratio of a magnetic material portion cross-sectional area of the magnetic material portion to a non-magnetic material portion cross-sectional area of the non-magnetic material portion at the core cross section is kept constant at each core cross section. Then, the core (1) has a plurality of cutting cores, in which the ratio of a magnetic material portion cross-sectional area to a non-magnetic material portion cross-sectional area is defferent.

Description

technical field [0001] The invention relates to a current sensor for determining the current flowing in a primary conductor. Background technique [0002] When measuring a large current, since it is dangerous to let the current directly flow into the ammeter, a current sensor is used, that is, the current is measured by reducing the primary current by using a current transformer (CT) and outputting it to the secondary side . The current transformer described above is an element utilizing AC characteristics, and has a structure in which a secondary current is read from a coil formed by winding a conductor around a core (core). [0003] However, even in the above-mentioned current sensor, a case occurs that when a large current measurement is performed, the magnetic flux generated on the above-mentioned core reaches saturation and current measurement cannot be performed correctly. Therefore, in order to achieve accurate current measurement and suppress the magnetic saturatio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F38/28H01F41/02G01R15/18
CPCH01F3/10H01F2027/2814H01F30/16H01F17/0033H01F3/14H01F38/30H01F27/346
Inventor 西浦龙一牧田阳西沢博志吉田忠广金太炫
Owner MITSUBISHI ELECTRIC CORP
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