KR102360792B1 - Shunt resistor and current detection device using the same - Google Patents

Abstract

A shunt resistor comprising copper as a main component and a shunt resistance resistor material comprising a Cu-Ni-Zn alloy containing nickel and zinc as a single resistor.

Description

Shunt resistor and current detection device using the same

The present invention relates to a shunt resistor and the like.

In recent years, the current used in electronic devices has been increased to about 1 kA, for example. In this case, in order to ensure safety when a circuit is short-circuited, it is necessary to control the short-circuit current. When such control is to be realized with a shunt resistor, a configuration that withstands a large current when the circuit is short-circuited becomes important. Also, since the short-circuit current occurs instantaneously, it is also important to detect the current instantaneously. .

Therefore, the shunt resistor used for this purpose is required to have a low resistance value of, for example, 100 μΩ or less. In such a case, it is possible to eliminate the connection between the electrode of the shunt resistor and the resistor as much as possible, or to shorten the length of the resistor as much as possible. Moreover, as a structure which eliminates the connection part of an electrode and a resistor, the structure which forms an electrode and a resistor with the same material, for example, manganese (Manganin) is also considered (for example, refer patent document 1).

However, when the electrode and the resistor of the shunt resistor are made of the same material, for example, copper having a small resistivity, the resistance decreases, but there is a problem that the TCR becomes large.

On the other hand, if the electrode and resistor of the shunt resistor are made of the same material, for example, manganin or geranine with a small TCR, the TCR can be made small, but the surplus resistance (the resistance value of the part outside the voltage measurement terminal) becomes large, so that the power There is a problem with increased consumption.

In addition, when the electrode and the resistor are formed of different materials, there is also a problem in that the mechanical strength is lowered at the junction (eg, the weld) between the electrode and the resistor.

Patent Document 1: Japanese Patent Application Laid-Open No. 2001-116771

An object of the present invention is to achieve low resistance and low TCR in a shunt resistor in which a resistor and an electrode are formed of the same material.

Another object of the present invention is to provide a current detection device suitable for detecting a short-circuit current of a large current using the shunt resistor as described above.

According to one aspect of the present invention, there is provided a shunt resistor in which a shunt resistor resistor material comprising copper as a main component and a Cu-Ni-Zn alloy containing nickel and zinc as a single resistor is provided. do.

It is preferable that the content of the Cu-Ni-Zn alloy is 1.5 to 10 wt% of Ni, 0.1 to 12 wt% of Zn, and the balance is Cu.

Moreover, it is preferable to contain 0.3-0.9 wt% of Si. Further, at least one metal among Sn and Mg may be contained in an amount of 0.1 to 1 wt%.

The Cu-Ni-Zn alloy may further contain 0.1 to 1 wt% of at least one metal among Si, Sn, Mg, and Ti.

According to the present invention, in the shunt resistor according to any one of the above, a pair of voltage detection terminals may be formed by raising a part of a plate body made of the single resistor body upright on the surface side.

The present invention is provided with the above-described shunt resistor and a current measuring circuit for measuring current by signals from a pair of first and second voltage signal lines respectively connected to the pair of voltage detecting terminals. A current measuring device may be used.

This specification includes the disclosure of Japanese Patent Application No. 2018-140647, which is the basis of the priority of the present application.

According to the present invention, in a shunt resistor in which the resistor and the electrode are made of the same material, low resistance and low TCR can be achieved.

1 is a perspective view showing a configuration example of a shunt resistor according to a first embodiment of the present invention.
Fig. 2 is a perspective view showing a configuration example of a current detection device using a shunt resistor according to a second embodiment of the present invention, and is a perspective view showing a configuration example before mounting the shunt resistor on the circuit board.
Fig. 3 is a perspective view showing a configuration example of a current detection device using a shunt resistor according to the present embodiment, and is a perspective view showing a configuration example after the shunt resistor is mounted on a circuit board.
Fig. 4 is a cross-sectional view taken along the line IIIa-IIIb in Fig. 3, and is a view showing a configuration example after the shunt resistor is mounted on the circuit board.
5 is a circuit diagram (block diagram) showing a configuration example of a current detection device using a shunt resistor according to the present embodiment.
6 is a perspective view of a shunt resistor according to a third embodiment of the present invention, in which a Cu-Ni-Zn alloy is used as a material for a plate body (resistor).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a shunt resistor according to an embodiment of the present invention and a current detection device using the same will be described in detail with reference to the drawings.

(First embodiment)

First, a first embodiment of the present invention will be described. 1 is a perspective view showing a configuration example of a shunt resistor according to the present embodiment.

As shown in FIG. 1, the shunt resistor A according to this embodiment is a shunt resistor which has a composition mentioned later and consists of a flat plate-shaped elongate plate body 1, for example. The shunt resistor A is provided with a pair of voltage detection terminals 11a and 11b spaced apart from each other in the longitudinal direction of the plate body 1 on a plate-shaped plate body 1 that is a single resistor. A pair of voltage detection terminals 11a and 11b by leaving the first side of the plate body 1 at two opposing places, cutting out the other three sides, and raising the two first sides to the front side as a reference. can be formed simply.

By doing as described above, the region inside the inner region (symbols L1 and L2) of the first side of the plate body 1 becomes the effective resistor 3 in current detection, and the region from the outer side to both ends is an effective electrode. It becomes (5a, 5b).

As shown in Fig. 1 , by cutting out the plate body 1 and bending it as it is, it is possible to obtain a voltage detection terminal with a short length while making it easy to shorten the interval by setting it as a voltage detection terminal. Also, an inductance value of the shunt resistor can be reduced.

Moreover, the voltage detection terminal may provide the pin-shaped terminal of another member in the plate body 1 other than the example shown in FIG. The pin-shaped terminal is fixed to the plate body 1 by welding a pin-shaped terminal to the surface of the plate body 1, forming a hole in the plate body 1 and inserting a pin-shaped terminal into this hole, etc. There is a way of

Further, in the shunt resistor shown in Fig. 1, a pair of hole portions 7a and 7b are formed at positions spaced apart from each other in the longitudinal direction of the plate body 1, and a bus bar (not shown) or a wiring board is formed. It is constructed so that it can be fixed to the back using bolts or the like.

Next, the composition of the material which forms the plate body 1 which consists of a single resistor body is demonstrated.

When the material of the plate body 1 is made of, for example, copper (100%) having a general composition, the resistivity value (µΩ/cm) is as low as about 1.72, but the TCR (ppm/°C) is as high as about 3970.

On the other hand, when the material of the plate body 1 is manganin (registered trademark), the TCR (ppm/°C) is as low as ±50, but the resistivity (µΩ/cm) is as high as 44. Moreover, when it is set as geranine 30 (trademark), TCR (ppm/degreeC) is as low as about 29, but resistivity value (microohm/cm) is as high as about 29.

Then, in this embodiment, the material of the board body 1 shown to the following table|surface was used. 4-5 and TCR of the specific resistance value of the plate body by this embodiment were 1000-2000. That is, compared to manganin, the resistivity is about 1/10, and the TCR is 1000 to 2000, which is higher than manganese, but lower than copper.

A1 B1 C1 D1 ingredient Ni Zn Si, Sn, Mg, Ti Cu Furtherance 1.5 to 10 0.1 to 12 0~1 rest (77-98.4)

Table 1 is a table which shows an example of the material of the board body 1 which concerns on this embodiment. As shown in Table 1, the main component of the material (alloy material) which forms the plate body 1 which consists of a single resistor is copper represented by the code|symbol D1, for example, 77-98.4 wt%. In addition to copper as the main component, in the present embodiment, zinc (Zn) denoted by a symbol (B1) and Ni denoted by a symbol (A1) are contained. In addition, as indicated by the symbol (C1), at least one of Si, Sn, Mg, and Ti is included in an amount of 0 to 1 wt%. The amount of zinc (Zn) is 0.1 to 12 wt%, and the amount of Ni is 1.5 to 10 wt% (100 wt% in total). In addition, the alloy material according to the present invention may contain unavoidable impurities.

In addition, considering that the manganese also contains Ni, for example, about 2 wt%, it can be inferred that the reason that the resistivity value can be lowered is due to the fact that the alloy is mixed with Zn. According to the inventor's guess, Zn easily forms an oxide film (ZnO). In an alloy containing Cu as a main component, by mixing a small amount of Zn, a ZnO oxide film on the surface of the alloy forming the plate body 1 serves as a surface protective film of copper, which is a bulk low-resistance metal. The effect of TCR reduction by containing Ni can also be acquired. Hereinafter, the alloy for plate bodies by this embodiment to which a predetermined amount of Zn is added is called a Cu-Ni-Zn alloy.

Moreover, you may add 0-1 wt% of at least 1 metal of Si, Sn, Mg, and Ti to a Cu-Ni-Zn alloy. Such an alloy is also called a Cu-Ni-Zn alloy.

When the Cu-Ni-Zn alloy according to the present embodiment is used, the durability at high temperature is good and the characteristics are stable. For example, under a high temperature of 175°C, when a high temperature stand test for 1000 hours was performed, the resistance value change amount showed a small variation value within ±0.5%.

Usually, copper and copper alloy different from this embodiment have low stability at high temperature, and the resistance value change due to oxidation shows a value larger than ±1%, so Cu-Ni according to this embodiment It can be said that -Zn alloy has stable properties and excellent durability.

(Second embodiment)

Next, a second embodiment of the present invention will be described. 2 and 3 are perspective views showing a configuration example of a current detection device using a shunt resistor according to the present embodiment, and FIG. 2 is a perspective view showing a configuration example before mounting the shunt resistor on the circuit board. Fig. 3 is a perspective view showing a configuration example after the shunt resistor is mounted on the circuit board. Fig. 4 is a cross-sectional view taken along the line IIIa-IIIb in Fig. 3, and is a view showing a configuration example after the shunt resistor is mounted on the circuit board. Fig. 5 is a circuit diagram (block diagram) showing a configuration example of a current detection device using a shunt resistor according to the present embodiment.

2 and 3, the shunt resistor A using the Cu-Ni-Zn alloy according to the first embodiment as a material of the plate body (resistor) 1 is used in a current measuring circuit, for example, an amplifier circuit. (B) is connected to the circuit including the current measuring device (X) is formed. The amplification circuit B is a circuit for amplifying the output signal from the shunt resistor A.

The shunt resistor A and the amplification circuit B are connected to the voltage detection terminals 11a and 11a provided in the shunt resistor A through a through hole formed in the circuit board 21 of the amplification circuit B. ) (through hole) 23a, 23b. An amplifier circuit (board) for amplifying an output signal from the shunt resistor A is provided on a circuit board 21 such as a printed circuit board on which the amplifier circuit B is formed. Further, reference numeral 35 denotes a terminal for outputting a signal from the amplifier circuit B to another control device or the like.

A shunt resistor and circuit components such as an amplifier on the circuit board 21 by using the through-holes 23a and 23b of the circuit board 21 to connect the voltage detection terminals 11a and 11b by solder joint. It can be connected by making the distance to (A) close.

Further, according to the cross-sectional view of the current detection circuit shown in Fig. 4, the plate body 1 of the shunt resistor A is cut out and bent as it is to form the voltage detection terminals 11a and 11b, whereby a pair of voltage detection terminals 11a , 11b) can form a terminal having a short interval and a short length. In addition, the inductance value of the shunt can be reduced, and durability can be secured.

As shown in Fig. 5, the amplifying circuit B includes, for example, a ΔΣ conversion analog isolation amplifier 25 by a photocoupler, an electrostatic coupling capacitor C, or the like. An A/D converter 27 is provided on the output side of the ΔΣ conversion analog isolation amplifier 25 via a wiring L13. The first signal output terminal 11a and the second signal output terminal 11b of the shunt resistor A are connected to two input terminals of the amplifier circuit by wirings L11 and L12, respectively.

The amplifier circuit B has an input terminal, and is respectively connected to the ΔΣ conversion analog isolation amplifier 25 via a resistor or the like. Further, a capacitor C is provided between the wirings L11 and L12 from the input terminals. Thereby, it is possible to suppress entry of normal mode noise or the like into the ΔΣ conversion analog isolation amplifier 25 . A positive (+) power supply terminal of the ΔΣ conversion analog isolation amplifier 25 is connected to Vcc, and a negative (-) power supply terminal is connected to GND (31).

By using the ΔΣ conversion analog isolation amplifier 25 by means of a photocoupler, an electrostatic coupling capacitor, or the like, the input side and the output side can be electrically insulated. Accordingly, it is possible to reduce the influence of noise on a pair of voltage signal lines (wirings L11 and L12) connected to the amplifying circuit provided in the current measuring device X for amplifying the signal.

Moreover, according to this embodiment, an output signal can be made into a digital output. Since the TCR characteristics of the shunt resistor A are not suitable for applications requiring high-precision current detection, it is desirable to reduce the processing burden on the control device side by making the output signal also a digital signal.

When the current value exceeds the specified value, a high level is output, and when the current value is within the specified value, a low level is outputted. The digital circuit used can be a simple circuit using a comparator or the like. In addition, the insulating function of the circuit can be realized with simple components such as the photo coupler as described above.

Furthermore, it is also possible to add the current detection circuit according to the present embodiment to other detection circuits. For example, a voltage detection circuit or the like may be provided and used for voltage detection or the like.

(Third embodiment)

Next, a third embodiment of the present invention will be described. This embodiment includes other types of shunt resistors. 6 is a perspective view of a shunt resistor using a Cu-Ni-Zn alloy as a material for the plate body (resistor) 1 as the shunt resistor according to the present embodiment.

As in the first embodiment, the shunt resistor D according to the present embodiment uses a Cu-Ni-Zn alloy as the elongated plate body 1 and presses, for example, the vicinity of the center of the central resistor 3, as in the first embodiment. ) has a bent structure that lifts the area upward. Other structures are the same as in FIG. 1 . The shunt resistor D having such a bent structure can be used by surface mounting on a circuit.

According to this embodiment, compared with the first embodiment, it is possible to further reduce the size of the shunt resistor.

(Fourth embodiment)

Next, a shunt resistor according to a fourth embodiment of the present invention will be described. The basic structure of the shunt resistor may be the same as that of the first to third several embodiments.

Table 2 is a diagram showing a more specific example of the composition ratio of each metal material shown in Table 1.

In the example shown in Example 1-1 among the Cu-Ni-Zn alloys shown in Table 2, for example, Ni is 1.5 to 4.0 wt%, Zn is 0.1 to 0.5 wt%, Si is 0.3 to 0.9 wt%, At least one metal among Sn and Mg is 0.1 to 1 wt%, and the balance is Cu (93.6 to 98 wt%) (100 wt% in total).

In this example, the specific resistance value is 4 to 5 μΩ·cm, and the TCR is about 1000 to 2000.

On the other hand, in the example represented by Example 1-2, for example, Ni is 1.6 wt%, Zn is 0.4 wt%, Si is 0.4 wt%, Sn is 0.5 wt%, the balance is Cu (about 97.1 wt%) to be.

In this example, the resistivity value is 4.3 µΩ·cm and the TCR is about 1500.

That is, since it corresponds to the case where the ratio of Cu in Table 1 is high, the resistivity value is lower than manganin and geranine 30, on the other hand, TCR shows a value higher than manganin and geranine 30. Therefore, it is effective when there is a high necessity to make a specific resistance value low.

(Fifth embodiment)

Next, a shunt resistor according to a fifth embodiment of the present invention will be described. The basic structure of the shunt resistor may be the same as that of the first embodiment.

Table 3 is a diagram showing a more specific example of the composition ratio of each metal material shown in Table 1.

In the example shown in Example 2-1 among the Cu-Ni-Zn alloys shown in Table 3, for example, Ni is 5-10 wt%, Zn is 5-12 wt%, Si and/or Ti is 0-1 wt% , the balance is Cu (about 77 to 90 wt%).

In this example, the specific resistance value is 10 to 15 μΩ·cm, and the TCR is about 200 to 1000.

On the other hand, in the example shown by Example 2-2, Ni is 6 wt%, Zn is 11 wt%, balance is Cu (about 83 wt%), for example.

In this example, the resistivity value is 11.5 μΩ·cm and the TCR is about 600.

That is, since it corresponds to the case in which the ratio of Cu in Table 1 is low, the resistivity value is lower than that of manganin or geranine 30, but higher than the case of Table 2, on the other hand, the TCR is higher than that of manganin or geranine 30, but It represents a lower value than the case. Therefore, it is effective when the resistance value is low but the TCR is not too high.

As described above, by including Zn, which is not contained in manganin or geranine 30, in the alloy, it is possible to reduce the resistance and reduce the TCR.

According to the fourth and fifth embodiments, it is possible to realize a shunt resistor having a TCR lower than that of copper and a resistance lower than that of manganese.

Therefore, according to this embodiment, in the shunt resistor in which the resistor and the electrode are formed of the same material, while realizing a low resistance, good TCR characteristics can be obtained.

Further, by adjusting the ratio of the elements to be added, as can be seen by comparing Tables 2 and 3, it is possible to manufacture a shunt resistor having desired characteristic values to some extent.

Further, according to the present embodiment, it is possible to determine such a material composition to provide an optimal shunt structure for detecting a short-circuit current.

Also, by connecting the current detection unit, a system capable of detecting a short-circuit current can be realized.

In the above embodiment, the illustrated configuration or the like is not limited thereto, and can be appropriately changed within the range of exhibiting the effects of the present invention. In addition, as long as it does not deviate from the range of the objective of this invention, it is possible to carry out by changing suitably.

In addition, each component of this invention can be arbitrarily cooked and selected, and invention provided with a self-selective structure is also included in this invention.

[Industrial Applicability]

The present invention is applicable to a shunt resistor.

A shunt resistor
B amplification circuit
X current measuring device
1 plate
3 resistor
5a, 5b electrodes
11a, 11b voltage detection terminals
21 circuit board
23a, 23b Through hole (through hole)
25 △Σ Conversion Analog Isolation Amplifier
27 A/D converter
All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety.

Claims (7)

A Cu-Ni-Zn alloy containing copper, nickel, and zinc is used as a shunt resistance resistor material consisting of a single resistor,
The Cu-Ni-Zn alloy has its content,
Ni is 1.5-10 wt%,
Zn is 0.1 to 12 wt%,
A shunt resistor with a remainder of Cu. delete The method according to claim 1,
Further, a shunt resistor comprising 0.3 to 0.9 wt% of Si. 4. The method according to claim 1 or 3,
In addition, the shunt resistor characterized in that it contains 0.1 to 1 wt% of at least one metal among Sn and Mg. The method according to claim 1,
In the Cu-Ni-Zn alloy,
In addition, a shunt resistor containing 0.1 to 1 wt% of at least one metal among Si, Sn, Mg, and Ti. A shunt resistor according to claim 1 or 3, comprising:
A shunt resistor in which a pair of voltage detection terminals are formed by raising a part of a plate body made of the single resistor body upright on the surface side. A shunt resistor according to claim 6,
and a current measuring circuit for measuring a current by a signal by a pair of first and second voltage signal lines respectively connected to the pair of voltage detecting terminals.

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