Shunt resistor support structure

Abstract

Shunt resistor support structure, which includes: a shunt resistor comprising a pair of electrodes (5a, 5b) and a resistive body (3), wherein the resistive body (3) is arranged longitudinally between the pair of electrodes (5a, 5b) and has a higher resistance than the pair of electrodes (5a, 5b); a pair of voltage detection terminals (17) which are each arranged adjacent to the electrodes (5a, 5b) of the resistive body (3), wherein each voltage detection terminal (17) is arranged at a longitudinally measured distance L2 from an end of the resistive body (3) facing the respective voltage detection terminal (17); a current detection substrate on which a control circuit is mounted, wherein the substrate (21) has a voltage detection section which is electrically connected to the pair of voltage detection terminals (17); a first temperature sensor (18a, 18c) for measuring a temperature of one electrode (5a, 5b) of the pair of electrodes (5a, 5b), wherein the first temperature sensor (18a, 18c) is arranged at a longitudinal distance L1 from the end of the resistive body (3) facing the first temperature sensor (18a, 18c), wherein the distance L1 is greater than the distance L2; and a second temperature sensor (18b) for measuring the temperature of the resistive body (3).

Description

Technical field

[0001] The present invention relates to a shunt resistor mounting structure (a current detection circuit using a shunt resistor). State of the art

[0002] A shunt resistor consisting of a resistive body and low-resistance electrodes provided at both ends thereof is known.

[0003] For example, patent literature 1 describes a semiconductor element for monitoring the electric current across a resistive body. The semiconductor element is arranged on a flat surface of a resistive element and / or power supply sections, thus establishing thermal contact with it. It states that this method makes it possible to create an inexpensive current measuring device capable of accurately monitoring the electric current in a power supply system with a large number of loads within a short time. List of literature on patent literature

[0004] Patent literature 1: JP 2003 - 270 724 A Summary of the invention: Technical problem

[0005] As in a perspective view from Fig. As shown in Figure 6, a shunt resistor 101 conventionally consists of, for example, two types of material: a resistive material forming a resistive body 103, and an electrode material forming electrodes 105a and 105b. The properties of these two materials cause changes in the resistance-temperature characteristics of the shunt resistor 101. One material is the resistive material, and the other is an electrically conductive material (conventionally copper) located between the shunt voltage detection signal terminals and the junctions between the resistive material and the electrode terminals. Fig. 6 is the region of the shunt resistor 101, which has a high temperature during current supply, i.e., the region of the resistive body 103, which is a body that heats up, indicated by hatching. As from Fig. As can be seen in Figure 6, temperature differences are caused between the electrodes 105a, 105b and the resistive body 103 at the time of current supply, when the temperatures of the boundary regions are particularly high.

[0006] The two types of material exhibit different electrical conductivity characteristics depending on the temperature, and the shunt resistance value-temperature characteristics are determined by assignment quantities that are determined by the structure of the shunt resistor and influence the shunt resistance value.

[0007] Fig. Figure 7 shows an example of temperature changes in the resistance value, which were determined using the shunt resistor 101.

[0008] The shunt resistance-temperature characteristic curves are determined by the assignment quantities, which are defined by the structure of the shunt resistor 101 and influence the shunt resistance value. The horizontal axis shows the temperature, and the vertical axis shows the rate of change of resistance in percent.

[0009] Based on Fig. 7. State 1 is a state in which the manganin temperature is equal to the copper temperature; state 2 is a state in which the manganin temperature is equal to the copper temperature + 15 °C; state 3 is a state in which the manganin temperature is equal to the copper temperature + 25 °C; and state 4 is a state in which the manganin temperature is equal to the copper temperature + 35 °C. In Fig. Figure 7, the solid line (state 1), shows an example in which the shunt resistor 101, to which no current is supplied, was placed in a bath at constant temperature and the resistance value measurement was carried out while the temperature was changed. Fig. 7 will receive the data for state 1.

[0010] However, this case does not take into account the influence of a temperature difference caused between a manganese section and a copper section in an actual current supply condition, as determined by Fig. As described in section 6. Therefore, the problem is that using only the temperature of one element does not constitute an integral temperature compensation control for high-precision current detection.

[0011] CN 1 07 851 494 A discloses a shunt resistor mounting structure comprising a shunt resistor containing a pair of electrodes and a resistive body, and a current detection substrate on which a control circuit is mounted. The substrate has a voltage detection section to which a pair of voltage detection terminals of the shunt resistor are connected. The resistive body is arranged longitudinally between the pair of electrodes and has a higher resistance than the electrodes. A pair of voltage detection terminals is located adjacent to the resistive body at each electrode. Each voltage detection terminal is positioned at a longitudinal distance from the end of the resistive body facing the respective voltage detection terminal.A temperature sensor is also provided for detecting the ambient temperature and thus indirectly the temperature of the electrodes. A current sensor arrangement with multiple temperature sensors is also described in DE 696 11 690 T2.

[0012] One object of the present invention is to create a temperature compensation control that is more accurate than a conventional control in a high-precision current detector based on TCR compensation of a shunt resistor in a current detection circuit that uses a shunt resistor.

[0013] Another object of the present invention is to enable the detection of an anomaly, e.g. due to a defective fastening of a shunt resistor mounting screw, before an overheating protection activation temperature is reached, thus making it possible to detect an anomaly without increasing the supply current. Solution to the problem

[0014] The problem is solved by creating a shunt resistor mounting structure with the features of claim 1. Advantageous embodiments are described in the dependent claims.

[0015] According to one aspect of the present invention, a shunt resistor mounting structure is provided comprising: a shunt resistor having a pair of electrodes and a resistive body arranged longitudinally between the pair of electrodes and having a higher resistance than the pair of electrodes; a current detection substrate on which a control circuit is mounted, the substrate having a voltage detection section electrically connected to the pair of voltage detection terminals of the shunt resistor; and a first temperature sensor for measuring a temperature of one electrode of the pair of electrodes.

[0016] Preferably, the first temperature sensor can be mounted on the substrate. Mounting it on the substrate allows for temperature correction and similar functions.

[0017] According to the invention, the shunt resistor mounting structure includes a second temperature sensor for measuring the temperature of the resistive body.

[0018] The second temperature sensor makes it possible to accurately measure the temperature of the resistive body, which is a body that heats up.

[0019] The shunt resistor mounting structure can include a third temperature sensor for measuring the temperature of the other electrode of the pair of electrodes.

[0020] Using the electrode temperatures measured by the first and third temperature sensors, and the temperature of the resistive body measured by the second temperature sensor, it is possible to improve the temperature compensation of a shunt resistance value.

[0021] According to the invention, the voltage detection terminals are arranged adjacent to the resistive body at the electrodes, and the first temperature sensor is arranged at a longitudinally measured distance L1 from an end of the resistive body facing the first temperature sensor, wherein the distance L1 is greater than a longitudinally measured distance L2, at which each voltage detection terminal is arranged from an end of the resistive body facing the respective voltage detection terminal.

[0022] Preferably, the first and third temperature sensors can be provided in positions that are further away from the resistive body than the voltage detection terminals.

[0023] By positioning them somewhat apart from a connection point section of the resistive body, which is a body that heats up, the influence of the heating of the resistive body can be suppressed.

[0024] The description contains the content disclosed in JP 2018 - 095 426, the priority of which is claimed by the present application. Advantageous effects of the invention

[0025] According to the present invention, it is possible to achieve highly accurate current detection for temperature compensation of the shunt resistance value.

[0026] According to the present invention, it is also possible to create a shunt current detector mounting structure that is highly secure, accurate and reliable. Brief description of the drawings Fig. Figure 1 is a perspective view showing a configuration example of a current detection device using a shunt resistor according to an embodiment of the present invention. Fig. Figure 2 is a perspective view showing a configuration example of a shunt resistor mounting structure, in which the current detector substrate with a control IC mounted on it is on the current detection device, which has a shunt resistor made of Fig. 1 is used, is mounted, represents. Fig. Figure 3 shows an enlarged view of Fig. 2 near a first temperature sensor. Fig. Figure 4 is a perspective view showing a configuration in which a housing is attached to hold the substrate in the Fig. to cover the mounting structure shown in section 2. Fig. Figure 5 is a functional block diagram that shows a configuration example of a temperature compensation circuit for the shunt resistor. Fig. Figure 6 is a perspective view showing a configuration example of a conventional shunt resistor. Fig. 7 provides an example using the in Fig. The 6 shown shunt resistance represents specific resistance value temperature changes. Description of embodiments

[0027] In the following, a shunt resistor mounting structure (a current detection circuit that uses a shunt resistor) according to an embodiment of the present invention is described in detail with reference to the drawings.

[0028] As used here, the direction in which the electrode - the resistive body - the electrode of a resistor is arranged is called the longitudinal direction, and a direction that intersects the longitudinal direction is called the transverse direction. (First embodiment)

[0029] First, a current detection device 1, which uses a shunt resistor according to a first embodiment of the present invention, is described. Fig. Figure 1 is a perspective view showing a configuration example of the current detection device 1, which uses a shunt resistor according to the present invention. The current detection device 1, which uses a shunt resistor, is shown in the diagram. Fig. The shunt resistor shown in Figure 1 is provided with: two electrodes 5a (a first electrode), 5b (a second electrode); a resistive body 3 arranged between the electrodes 5a, 5b; and voltage detection terminals 17. A section consisting of the resistive body 3 and the electrodes 5a, 5b can also be referred to as an electrically conductive body. The electrodes 5a, 5b can be referred to as electrode terminals. Each of the electrodes 5a, 5b is provided with a main electrode section (where the main electrode section is defined as a section of 5a, 5b excluding 5c, 5d) on its end face and with a narrow electrode section 5c, 5d on the side of the resistive body 3, the width of which is 2W2 smaller than the width of the main electrode section. The resistive body 3 is arranged between the narrow electrode sections 5c, 5d.The narrow electrode sections 5c, 5d each have a dimension W1 in the longitudinal direction. The dimension W1 is, for example, on the order of 1 to 3 mm. The reference numeral 15 in . Fig. 1 indicates screw holes.

[0030] Both the electrode material and the resistive material can be obtained, for example, by cutting an elongated material (a plate).

[0031] In the present example, the voltage detection terminals 17 are provided, one in each of the main electrode sections near the narrow electrode sections 5c, 5d.

[0032] The voltage detection terminals 17 can be provided in the narrow electrode sections 5c, 5d. By providing the voltage detection terminals 17 in the narrow electrode sections 5c, 5d or in the vicinity of the main electrodes, it is possible to reduce the distance between the voltage detection terminals 17 and improve the accuracy of the current measurement by four-pole sensing.

[0033] In the Fig. In the structure shown in Figure 1, it is possible to form a narrow section or a section with a reduced width by providing the recesses 7. The recesses 7 are located internally in the width direction within sub-regions containing the connection sections 13a, 13b, which are formed by welding or similar processes between the resistive body 3 and the electrode sections 5a, 5b. In this case, the width of the narrow electrode sections 5c, 5d and the width of the resistive body 3 are essentially the same. The section with a reduced width formed by the recesses 7 is referred to as a narrow section or a section with a reduced width.

[0034] For example, the material for the resistive element forming resistive body 3 could be a sheet-shaped metal based on a Cu-Ni, Cu-Mn, or Ni-Cr base. Alternatively, Manganin (registered trademark), which comprises 86% copper, 12% manganese, and 2% nickel, could be used. An example containing, but not limited to, Manganin is described below.

[0035] Fig. Figure 2 is a perspective view showing a configuration example of a shunt resistor mounting structure, in which a substrate 21 of a current detector equipped with a control IC is mounted on the current detection device 1, which has a Fig. The shunt resistor shown in section 1 is used and mounted.

[0036] As in Fig. As shown in Figure 2, the substrate 21 is arranged vertically on a surface 2a of the current detection device 1, which uses a shunt resistor. In the example from Fig. In Figure 2, a control IC 51 is mounted on a surface 21a of the substrate 21. One surface 2a borders a side surface 21b and the intersecting surface 21a of the substrate 21. In this configuration, one surface 21a of the substrate 21 is formed with terminal sections 31, 31 to accommodate, for example, the two voltage detection terminals 17, 17. The terminal sections 31, 31 have terminal entry holes 31a, 31a, which are formed for inserting the two voltage detection terminals 17, 17. The two voltage detection terminals 17, 17 are electrically connected in the terminal entry holes 31a, 31a to wires or the like, which are not shown but are formed on the substrate 21. Accordingly, voltage signals are transmitted from the two voltage detection terminals 17, 17 to the control IC 51 on the substrate 21.The control IC 51 is able to determine a current flowing through the shunt resistor based on the voltage signals from the two voltage detection terminals 17, 17.

[0037] A connector 41 is formed on the substrate 21, which includes a connection section 43 for connection to an external device or the like. Thus, it is possible to execute a process via the connector to cause a current value determined by the control IC 51 to be displayed, for example, on the external device.

[0038] Furthermore, one surface 21a of the substrate 21 above the other surface 2a is equipped with a first temperature sensor 18a, a second temperature sensor 18b, and a third temperature sensor 18c. The detection signals from the temperature sensors can be read, for example, by the control IC 51.

[0039] The first temperature sensor 18a is provided above the electrode 5b and detects the temperature of the electrode 5b. The first temperature sensor 18a is preferably provided above the electrode 5b in the vicinity of the resistive body 3 or in the vicinity of the recesses 7.

[0040] The second temperature sensor 18b is provided above the resistive body 3 and detects the temperature of the resistive body 3.

[0041] The third temperature sensor 18c is provided above the electrode 5a and detects the temperature of the electrode 5a. The third temperature sensor 18c is preferably provided above the electrode 5a in the vicinity of the resistive body 3 or in the vicinity of the recesses 7.

[0042] Fig. Figure 3 is an enlarged view near the first temperature sensor 18. Fig. 2. As in Fig. 2 and Fig. As shown in Figure 3, the position at which the first temperature sensor 18a is arranged is preferably further apart in the longitudinal direction from the resistive body 3 than the voltage detection terminal 17. For example, as shown in Fig. As shown in Figure 3, L1 > L2 if the longitudinal distance from the position (the midpoint in the longitudinal direction) of the first temperature sensor 18 to the connection section 13b is L1, and the longitudinal distance from the position (the midpoint) of the voltage detection terminal 17 to the connection section 13b is L2. L1 is set longer than L2 because the probability of being exposed to the influence of the heating of the resistive body 3 is higher if it is too close to the connection section 13b of the resistive body 3, which is a heat-generating body.

[0043] Preferably, the third temperature sensor 18c has a similar positional relationship to the first temperature sensor 18a.

[0044] Preferably, the second temperature sensor 18b is positioned in the center along the longitudinal axis of the resistive body 3. This makes it possible to accurately measure the temperature of the resistive body 3.

[0045] Fig. Figure 4 is a perspective view showing a configuration in which a housing 80 is attached to support the substrate 21 in the mounting structure. Fig. 2 to cover. For example, a first housing element 81 and a second housing element 83 are provided to enclose the substrate 21. The first housing element 81 and the second housing element 83 can be configured to be assembled into the single housing 80 using a known assembly structure. The housing 80 is configured such that the connection section 43 of the substrate 21 is located outside the housing 80. In this way, it is possible to easily connect signal cables or the like to the connection section 43. Furthermore, the electrode sections 5a, 5b are also configured to protrude outside the housing 80. In this way, it is possible to apply a desired voltage across the electrodes 5a, 5b of the shunt resistor.

[0046] As described above, the substrate 21 can be protected by adopting the structure in which the housing elements 81, 83 cover the periphery of the resistive body 3. Since the substrate 21 and the resistive body 3 are also enclosed in the housing, it is possible to perform more precise temperature compensation, taking into account the influence of the housing, by means of temperature equalization with the first to the third temperature sensors 18a to 18c, which are provided for the resistive body 3 and for the electrodes 5a, 5b in its vicinity. (Explanation of the temperature compensation circuit)

[0047] The following describes a temperature compensation circuit that uses the first to third temperature sensors 18a to 18c. The temperature compensation circuit can be mounted in the control IC 51.

[0048] Fig. Figure 5 is a functional block diagram of a configuration example of a temperature compensation circuit 61 of the shunt resistor 1. As in Fig.As shown in Figure 5, the temperature compensation circuit 61 is equipped with: an average value calculation circuit 61-1, which calculates an average value of a measured temperature θ1 at the first temperature sensor 18a, a measured temperature θ2 at the second temperature sensor 18b, and a measured temperature θ3 at the third temperature sensor 18c; a temperature change calculation unit 61-2, which, based on the measured temperature θ2 and θpin, which is the output of the average value calculation circuit 61-1, calculates a temperature change (temperature increase) Δθ of the resistive body 3 made of manganese or the like; a resistance value calculation unit (which contains a resistance value table) 61-3, which determines a resistance value based on Δθ and θpin;a current calculation unit 61-4, which determines a current detected from the output of a processing unit 61-5 and from the resistance value, wherein the processing unit 61-5 determines the gain and the bias of the shunt resistor 1; and a current signal output calculation unit 61-6, which determines a current signal output based on the determined current I.

[0049] As described above, it is possible to achieve highly accurate temperature compensation using the temperature compensation circuit in which the first to third temperature sensors 18a to 18c are used.

[0050] In the configuration described above, a high-precision current detection device using a shunt resistor incorporates temperature detection points to compensate for the resistance-temperature characteristics of the manganese or similar resistive element section and also for the copper sections near the shunt voltage output signals. This allows for more accurate measurement of the resistive body and electrode temperatures, thus achieving a more precise temperature compensation.

[0051] As described above, the shunt resistor mounting structure of the present embodiment enables highly accurate current detection by taking into account the temperature difference that occurs at the time of supply between the resistive body made of manganin or the like and the electrodes made of copper or the like, for the temperature compensation of the shunt resistor value.

[0052] Furthermore, in the case of an unusual temperature increase due to a shunt resistor mounting screw fault, an anomaly at or below an overheating protection level can be detected at a shunt resistor absolute value temperature, making it possible to create a shunt current detector that is highly safe, accurate and reliable.

[0053] In the foregoing embodiment, the configurations and the like shown are not to be understood as limiting, but can be modified as required, as long as the effects of the present invention are achieved. Other modifications can be made and implemented as required without deviating from the scope of protection of the object of the present invention.

[0054] The respective components of the present invention can be adopted as required, and an invention comprising an optionally adopted configuration is also included in the present invention. Industrial applicability

[0055] The present invention can be used in a shunt resistor mounting structure. Reference symbol list 1 Current detection device that uses a shunt resistor 3 resistive body 5a, 5b Electrode 13a, 13b Junction section 17 Voltage detection connection 18a first temperature sensor 18b second temperature sensor 18c third temperature sensor 21 Substrat 31a, 31a Connection entry hole 43 Connection section 51 Control IC 81 first housing element 83 second housing element

[0056] All publications, patents and patent applications cited in the present invention are included here in their entirety by reference to literature.

Claims

[1] Shunt resistor support structure comprising: a shunt resistor comprising a pair of electrodes (5a, 5b) and a resistive body (3), wherein the resistive body (3) is arranged longitudinally between the pair of electrodes (5a, 5b) and has a higher resistance than the pair of electrodes (5a, 5b); a pair of voltage detection terminals (17) which are each arranged adjacent to the electrodes (5a, 5b) of the resistive body (3), wherein each voltage detection terminal (17) is arranged at a longitudinally measured distance L2 from an end of the resistive body (3) facing the respective voltage detection terminal (17); a current detection substrate on which a control circuit is mounted, wherein the substrate (21) has a voltage detection section which is electrically connected to the pair of voltage detection terminals (17); a first temperature sensor (18a, 18c) for measuring a temperature of one electrode (5a, 5b) of the pair of electrodes (5a, 5b), wherein the first temperature sensor (18a, 18c) is arranged at a longitudinal distance L1 from the end of the resistive body (3) facing the first temperature sensor (18a, 18c), wherein the distance L1 is greater than the distance L2; and a second temperature sensor (18b) for measuring the temperature of the resistive body (3). [2] Shunt resistor mounting structure according to claim 1, wherein the first and second temperature sensors (18a, 18c; 18b) are mounted on the substrate (21). [3] Shunt resistor mounting structure according to one of claims 1 or 2, with a third temperature sensor (18c, 18a) for measuring the temperature of the other electrode (5a, 5b) of the pair of electrodes (5a, 5b). [4] Shunt resistor mounting structure according to claim 3, wherein the first and third temperature sensors (18a, 18c) are provided at positions that are spaced further apart from the resistive body (3) than the voltage detection terminals (17).

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