Direct-current short-circuit protection device

Abstract

The DC short circuit protection device includes: a fuse having a bus bar and cutting off the bus bar in response to an ignition signal; a first current detection unit that has a first resistance unit and detects a current flowing through the bus bar; a second current detection unit that has a second resistance unit and detects a current flowing through the bus bar; and a disconnection control circuit that outputs the ignition signal to the fuse on the basis of a first detection signal output from the first current detection unit and a second detection signal output from the second current detection unit. The first resistor part and the second resistor part are integrated with the bus bar so that a current of the same magnitude as a current flowing through the bus bar flows, and the resistance value of the first resistor part and the resistance value of the second resistor part are different.

Description

Technical Field

[0001] The present disclosure relates to a direct current short circuit protection device. Background Art

[0002] Patent Document 1 describes a technique for miniaturizing a circuit breaker device by integrating a sensor for current detection with the circuit breaker device.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-136055 Summary of the invention

[0006] However, in the circuit disconnection device described in Patent Document 1, when the current flowing through the device greatly changes due to noise, etc., a counter electromotive force (V=-L×di / dt) is generated due to the influence of the inductance component in the sensor (shunt resistor) used for current detection. Due to this counter electromotive force, the detected current value may be larger than the original value, which may cause an erroneous circuit break.

[0007] Therefore, the present disclosure provides a DC short-circuit protection device capable of suppressing erroneous disconnection caused by the influence of an inductance component.

[0008] A DC short-circuit protection device of one embodiment of the present invention comprises: a fuse having a bus bar, which cuts off the bus bar in response to an ignition signal; a first current detection unit having a first resistor unit, which detects the current flowing through the bus bar; a second current detection unit having a second resistor unit, which detects the current flowing through the bus bar; and a circuit breaker control circuit, which outputs the ignition signal to the fuse based on a first detection signal output from the first current detection unit and a second detection signal output from the second current detection unit, wherein the first resistor unit and the second resistor unit are integrated with the bus bar in such a way that a current of the same magnitude as the current flowing through the bus bar flows through the first resistor unit and the second resistor unit have different resistance values.

[0009] According to the DC short-circuit protection device of one aspect of the present disclosure, it is possible to suppress erroneous disconnection due to the influence of the inductance component. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural diagram showing an example of a DC short-circuit protection device according to an embodiment.

[0011] Figure 2 It is a perspective view of the active fuse in the first example.

[0012] Figure 3It is a partial cross-sectional view of the active fuse in the first example.

[0013] Figure 4 It is a perspective view of the active fuse in the second example.

[0014] Figure 5 It is a partial cross-sectional view of the active fuse in the third example.

[0015] Figure 6 It is a partial cross-sectional view of the active fuse in the fourth example.

[0016] Figure 7 It is a bottom view of the bus bar in the fourth example.

[0017] Figure 8 It is a diagram for explaining the cross-sectional structure of the bus bar in the fourth example.

[0018] Fig. 9 4 is a top view of the bus bar in the fifth example. DETAILED DESCRIPTION

[0019] Hereinafter, the embodiments will be described in detail with reference to the drawings.

[0020] In addition, the embodiments described below are all general or specific examples. The numerical values, shapes, materials, components, configuration positions and connection methods of the components shown in the following embodiments are examples and are not intended to limit the present disclosure.

[0021] (Implementation Method)

[0022] use Figure 1 A DC short-circuit protection device 1 according to the embodiment will be described.

[0023] Figure 1 It is a structural diagram showing an example of the DC short-circuit protection device 1 according to the embodiment.

[0024] The DC short-circuit protection device 1 is installed in a vehicle such as an electric vehicle that uses electric power for propulsion drive. A high-voltage battery is installed in a vehicle such as an electric vehicle, and electric power is supplied from the battery to a load such as an electric motor, thereby performing propulsion drive of the vehicle such as the electric vehicle. When an accident occurs, a large current caused by a short-circuit abnormality flows in the path connecting the battery and the load, and the battery may smoke or catch fire. Therefore, the DC short-circuit protection device 1 is provided to disconnect the path.

[0025] The DC short-circuit protection device 1 includes an active fuse 10 and a disconnection control circuit 20 .

[0026] The active fuse 10 is a device for cutting off the path connecting the battery and the load when a large current caused by a short circuit anomaly flows through the path, such as a smart fuse. The smart fuse contains gunpowder, which is ignited based on a control signal from the outside, thereby irreversibly cutting off the busbar by the explosive force caused by the ignition of the gunpowder to cut off the current. The active fuse 10 has a cutter 11, a busbar 12, and a plurality of current detection units. Here, two current detection units 13a and 13b are shown as the plurality of current detection units, but the plurality of current detection units may be more than three. In addition, when the number of current detection units is large, the detection signal of each current detection unit needs to be processed, and the processing load increases. Therefore, in the present disclosure, an example is described in which the plurality of current detection units are not more than four but two or three.

[0027] The bus bar 12 is a long conductor bar connected (e.g., fastened) to a path connecting a battery and a load and serving as a part of the path. The cutter 11 cuts the bus bar 12 by an ignition signal from the cutoff control circuit 20. Since the bus bar 12 is a part of the path, the path can be cut off by cutting the bus bar 12.

[0028] Figure 2 1 is a perspective view of an example of an active fuse 10. Figure 2 As shown, the current detection unit 13a has a resistor 131a, which is a current sensor for detecting the current flowing through the bus bar 12. The current detection unit 13a is an example of a first current detection unit. The resistor 131a is an example of a first resistor. The current detection unit 13b has a resistor 131b, which is a current sensor for detecting the current flowing through the bus bar 12. The current detection unit 13b is an example of a second current detection unit. The resistor 131b is an example of a second resistor. The resistors 131a and 131b are integrated with the bus bar 12 in such a way that a current of the same magnitude as the current flowing through the bus bar 12 flows. An example of integration is described below. The current detection unit 13a detects the current flowing through the bus bar 12 by converting the current flowing through the resistor 131a into a voltage. The current detection unit 13b detects the current flowing through the bus bar 12 by converting the current flowing through the resistor 131b into a voltage.

[0029] The circuit breaker control circuit 20 is connected to the active fuse 10, and cuts off the bus bar 12 by controlling the active fuse 10. Specifically, the circuit breaker control circuit 20 outputs an ignition signal S3 to the active fuse 10 based on the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b. If the ignition signal S3 is input, the cutter 11 cuts off the bus bar 12. The circuit breaker control circuit 20 is implemented by, for example, a microcontroller unit (MCU: Micro Controller Unit). The circuit breaker control circuit 20 includes a detection signal acquisition unit 21, a circuit breaker determination unit 22, a comparison unit 23, and an ignition control circuit 24.

[0030] The detection signal acquisition unit 21 acquires the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b. For example, the detection signal S1 is a signal indicating a voltage generated when current flows through the resistor 131a of the current detection unit 13a, and the detection signal S2 is a signal indicating a voltage generated when current flows through the resistor 131b of the current detection unit 13b.

[0031] The disconnection determination unit 22 determines whether to disconnect the path connecting the battery and the load based on the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b. For example, the disconnection determination unit 22 performs a predetermined operation based on the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b, thereby determining whether the bus bar 12 can be disconnected. The details of the predetermined operation are described below.

[0032] The comparison unit 23 compares the first current value calculated based on the detection signal S1 output from the current detection unit 13a with the second current value calculated based on the detection signal S2 output from the current detection unit 13b. Specifically, the comparison unit 23 calculates the first current value by dividing the voltage indicated by the detection signal S1 output from the current detection unit 13a by the resistance value of the resistor 131a, and calculates the second current value by dividing the voltage indicated by the detection signal S2 output from the current detection unit 13b by the resistance value of the resistor 131b. The comparison unit 23 performs fault detection of the current detection units 13a and 13b based on the comparison result of the first current value and the second current value. For example, when the first current value is different from the second current value, the comparison unit 23 determines that one of the current detection units 13a and 13b has a fault. For example, when any one of the current detection units 13a and 13b has a fault, the circuit breaker control circuit 20 can notify the external device of the situation.

[0033] When the disconnection determination unit 22 determines that the bus bar 12 can be disconnected, the ignition control circuit 24 outputs an ignition signal S3 to the active fuse 10. Thus, when a large current due to a short circuit abnormality flows through the path, the active fuse 10 can disconnect the bus bar 12 to disconnect the path.

[0034] There are various embodiments of the DC short-circuit protection device 1 , and the first to fifth embodiments are described below.

[0035] (first example)

[0036] First, use Figure 2 and Figure 3 A first example of the DC short-circuit protection device 1 will be described.

[0037] Figure 2 1 is a perspective view of the active fuse 10 in the first example.

[0038] Figure 3 FIG. 1 is a partial cross-sectional view of the active fuse 10 in the first example. Figure 3 In FIG. 1 , the cross-section of the cutting machine 11 is omitted.

[0039] The cutting machine 11 includes, for example, an ignition terminal 11a and a cutting blade 11b. The ignition terminal 11a is connected to an ignition control circuit 24 of the circuit breaker control circuit 20. When an ignition signal S3 (see Figure 1 ), the cutting machine 11 instantly presses the cutting blade 11b downward to cut the bus bar 12.

[0040] For example, the bus bar 12 is provided with a fastening portion 12a at one end in the long-side direction of the bus bar 12, and a fastening portion 12b is provided at the other end in the long-side direction of the bus bar 12. The bus bar 12 is inserted in the middle of the path connecting the battery and the load, and the fastening portions 12a and 12b are fastened to the path by screws or the like. Thus, the bus bar 12 becomes a part of the above-mentioned path. The cut portion 121 of the bus bar 12 is a portion cut by the cutting blade 11b of the cutter 11 when the ignition signal S3 is output from the circuit breaker control circuit 20.

[0041] In the present disclosure, the resistance value of the resistor 131a of the current detection unit 13a and the resistance value of the resistor 131b of the current detection unit 13b are different values. For example, the resistors 131a and 131b are resistance elements (shunt resistors) of about tens of micro-ohms. Figure 2 and Figure 3As shown, the resistors 131a and 131b are integrated with the bus bar 12 by being inserted into the bus bar 12. In addition, in the fourth and fifth examples described later, examples are described in which the resistors 131a and 131b are not resistor elements but are parts of the bus bar 12, and are integrated with the bus bar 12 as parts of the bus bar 12. In the resistors 131a and 131b integrated with the bus bar 12, the current flowing through the bus bar 12 can be detected by converting the current flowing through the bus bar 12 into a voltage.

[0042] In the first example, the current detection unit 13a has two current monitoring terminals 132a and 133a for monitoring the current flowing through the resistor unit 131a, and the current monitoring terminals 132a and 133a are provided on the bus bar 12 in such a manner that the resistor unit 131a is located between the current monitoring terminals 132a and 133a. In addition, the current detection unit 13b has two current monitoring terminals 132b and 133b for monitoring the current flowing through the resistor unit 131b, and the current monitoring terminals 132b and 133b are provided on the bus bar 12 in such a manner that the resistor unit 131b is located between the current monitoring terminals 132b and 133b. For example, the distance between the current monitoring terminals 132a and 133a is substantially the same as the distance between the current monitoring terminals 132b and 133b. In other words, the inductance component between the current monitoring terminals 132a and 133a is substantially the same as the inductance component between the current monitoring terminals 132b and 133b.

[0043] The current monitoring terminals 132a, 133a, 132b, and 133b are connected to the detection signal acquisition unit 21 of the circuit breaker control circuit 20. The detection signal acquisition unit 21 acquires the voltage between the current monitoring terminals 132a and 133a and the voltage between the current monitoring terminals 132b and 133b as detection signals, respectively. The voltage between the current monitoring terminals 132a and 133a is the voltage generated in the resistor 131a due to the current flowing through the resistor 131a, and the voltage between the current monitoring terminals 132b and 133b is the voltage generated in the resistor 131b due to the current flowing through the resistor 131b.

[0044] As described above, the disconnection control circuit 20 performs a predetermined operation based on the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b, thereby determining whether the bus bar 12 can be disconnected. The predetermined operation includes the operation of dividing the difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b by the difference between the resistance value of the resistor 131a of the current detection unit 13a and the resistance value of the resistor 131b of the current detection unit 13b. The details are described below. By performing such an operation on the detection signals S1 and S2 respectively output from the current detection units 13a and 13b having the resistors 131a and 131b having different resistance values, it is possible to suppress erroneous disconnection caused by the influence of the inductance component while detecting the current flowing through the bus bar 12.

[0045] When the current value based on the result of the above-mentioned predetermined calculation is equal to or larger than a predetermined value, that is, when a large current flows through the bus bar 12 , the disconnection determination unit 22 determines to disconnect the above-mentioned path.

[0046] In the first example, the current detection units 13 a and 13 b are provided outside the frame of the active fuse 10 . However, at least one of the current detection units 13 a and 13 b may be provided inside the frame of the active fuse 10 .

[0047] In addition, the cutting machine 11 may include a plurality of cutting blades, and when the firing signal S3 is output from the cutting control circuit 20 , the bus bar 12 may be cut at a plurality of locations.

[0048] As described above, the DC short-circuit protection device 1 includes an active fuse 10 having a bus bar 12, which responds to the ignition signal S3 (see Figure 1 ) to cut off the bus bar 12; a current detecting unit 13a, having a resistor unit 131a, for detecting the current flowing through the bus bar 12; a current detecting unit 13b, having a resistor unit 131b, for detecting the current flowing through the bus bar 12; and a circuit breaker control circuit 20, which outputs an ignition signal S3 to the active fuse 10 based on a detection signal S1 output from the current detecting unit 13a and a detection signal S2 output from the current detecting unit 13b, wherein the resistor units 131a and 131b are integrated with the bus bar 12 in such a way that a current of the same magnitude as the current flowing through the bus bar 12 flows, and the resistance value of the resistor unit 131a and the resistance value of the resistor unit 131b are different values.

[0049] When there is a large change in the current flowing through the bus bar 12 due to noise or sudden acceleration of the vehicle, etc. (i.e., when di / dt is large), a large back electromotive force (V=-L×di / dt) is generated in the resistors 131a and 131b due to the influence of their respective inductance components (L). The detection signals S1 and S2 output from the current detection units 13a and 13b contain such a large back electromotive force component. Therefore, due to this back electromotive force, the detected current value may be larger than the original value, and an erroneous circuit may occur. However, there is no corresponding relationship between the resistance value of the resistors 131a and 131b and the inductance component. Even if the resistance value of the resistor 131a and the resistance value of the resistor 131b are different values, the back electromotive force generated in the resistor 131a and the back electromotive force generated in the resistor 131b are approximately the same. Therefore, in the present disclosure, the back electromotive force component included in each detection signal is eliminated by obtaining the difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b. Therefore, it is possible to suppress erroneous disconnection caused by the influence of the inductance component.

[0050] Furthermore, in the resistors 131a and 131b having different resistance values, voltages of different magnitudes are generated according to the resistance values ​​when current flows through the bus bar 12. Therefore, when obtaining the difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b, the component of the voltage generated by the current flowing through the bus bar 12 can be retained. Therefore, it is possible to detect the current flowing through the bus bar 12 while suppressing erroneous disconnection caused by the influence of the inductance component.

[0051] For example, the circuit breaker control circuit 20 can determine whether the bus bar 12 can be cut by performing a predetermined operation based on the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b, and output an ignition signal to the active fuse 10 when it is determined that the bus bar 12 can be cut. For example, the predetermined operation may include an operation of dividing the difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b by the difference between the resistance value of the resistor 131a and the resistance value of the resistor 131b.

[0052] Thus, the difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b includes the difference between the voltage generated in the resistor 131a and the voltage generated in the resistor 131b due to the current flowing through the bus bar 12. The difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b is a voltage corresponding to the difference between the resistance value of the resistor 131a and the resistance value of the resistor 131b, so the current flowing through the bus bar 12 can be detected by dividing the difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b by the difference between the resistance value of the resistor 131a and the resistance value of the resistor 131b.

[0053] For example, the current detection unit 13a may include the current monitoring terminals 132a and 133a for monitoring the current flowing through the resistor 131a, and the current detection unit 13b may include the current monitoring terminals 132b and 133b for monitoring the current flowing through the resistor 131b.

[0054] In this way, the current monitoring terminals 132a, 133a, 132b, and 133b can be provided in the current detecting parts 13a and 13b.

[0055] For example, the DC short-circuit protection device 1 may further include a comparison unit 23, which compares a first current value based on a detection signal S1 output from the current detection unit 13a and a second current value based on a detection signal S2 output from the current detection unit 13b. The comparison unit 23 performs fault detection of the current detection unit 13a or 13b based on the comparison result of the first current value and the second current value.

[0056] Thus, the same current flows through the resistors 131a and 131b of the current detection units 13a and 13b, respectively. Therefore, the first current value and the second current value based on the detection signals S1 and S2 output from the current detection units 13a and 13b should be the same. However, when a failure occurs in either of the current detection units 13a and 13b, the current values ​​may be different. Therefore, when the first current value and the second current value are different, it can be detected that a failure occurs in either of the current detection units 13a and 13b.

[0057] (Second example)

[0058] Next, use Figure 4 A second example of the DC short-circuit protection device 1 will be described.

[0059] Figure 4 It is a perspective view of the active fuse 10 in the second example.

[0060] In the second example, the bus bar 12 is provided with a temperature monitoring terminal 140 for monitoring the temperature of the bus bar 12. Other points are the same as those of the first example, and thus description thereof is omitted.

[0061] The temperature monitoring terminal 140 is connected to a thermistor or a thermocouple to monitor the temperature of the bus bar 12. The temperature of the bus bar 12 is acquired by the disconnection control circuit 20 and used by the disconnection determination unit 22 to calculate the current value of the current flowing through the bus bar 12.

[0062] The resistance value of the resistors 131a and 131b changes according to the temperature, and accordingly, the voltage generated in the resistors 131a and 131b changes. Therefore, the calculation result of the current flowing through the bus bar 12 changes according to the temperature. Therefore, the temperature of the bus bar 12 in which the resistors 131a and 131b are integrated is monitored, and the detection signals of the current detection units 13a and 13b or the calculated current value are corrected according to the temperature of the bus bar 12, so that the current flowing through the bus bar 12 can be accurately detected.

[0063] (Third example)

[0064] Next, use Figure 5 A third example of the DC short-circuit protection device 1 will be described.

[0065] Figure 5 FIG. 1 is a partial cross-sectional view of the active fuse 10 in the third example. Figure 5 In FIG. 1 , the cross-section of the cutting machine 11 is omitted. Figure 5 In the figure, the current monitoring terminal is omitted.

[0066] In the third example, the active fuse 10 further includes a current detection unit 13c (resistance unit 131c). Other points are the same as those in the first example, and thus description thereof will be omitted.

[0067] In the third example, the active fuse 10 has three current detection units 13a to 13c, thereby being able to identify a faulty current detection unit among the three current detection units 13a to 13c. Specifically, when the current value based on the detection signal output from one of the three current detection units 13a to 13c becomes a value different from two current values ​​based on the detection signals output from the other two current detection units, it is possible to detect that the current detection unit has failed.

[0068] exist Figure 5 In the figure, an example is shown in which the current detection unit 13c is arranged in the frame of the active fuse 10, but two or more of the three current detection units 13a~13c may be arranged in the frame of the active fuse 10, or all the three current detection units may be arranged outside the frame of the active fuse 10.

[0069] Furthermore, in the third example, the bus bar 12 may be provided with a temperature monitoring terminal 140 .

[0070] (Fourth example)

[0071] Next, use Figures 6 to 8 A fourth example of the DC short-circuit protection device 1 will be described.

[0072] Figure 6 FIG. 1 is a partial cross-sectional view of the active fuse 10 in the fourth example. Figure 6 In FIG. 1 , the cross-section of the cutting machine 11 is omitted.

[0073] Figure 7 It is a bottom view of the bus bar 12 in the fourth example.

[0074] Figure 8 1 is a diagram for explaining the cross-sectional structure of the bus bar 12 in the fourth example. Figure 8 In the figure, the current monitoring terminal is omitted.

[0075] In the fourth example, the resistors 131a and 131b are part of the bus bar 12, and the part with increased resistance value is used as the resistors 131a and 131b by narrowing or thinning a part of the bus bar 12. Specifically, the area of ​​the cross section of the resistors 131a and 131b of the bus bar 12 perpendicular to the direction of current flow is smaller than the area of ​​the cross section of the part other than the resistors 131a and 131b of the bus bar 12 perpendicular to the direction of current flow. Figure 7 and Figure 8 As shown in FIG. 1 , it can be seen that the cross-sectional area of ​​the resistor portions 131a and 131b is ( Figure 8 The area of ​​the BB' cross section and the area of ​​the DD' cross section) are smaller than the cross section area of ​​the portion other than the resistor portions 131a and 131b (for example Figure 8 The area of ​​the AA' section and the area of ​​the CC' section of the cross section are respectively connected to the two ends of the portion where the cross section area becomes smaller. The voltage generated by the current flowing through the portion can be obtained through the current monitoring terminals, thereby enabling the portion to be used as a current detection unit.

[0076] In the fourth example, the area of ​​the cross section perpendicular to the direction of current flow in the resistor portion 131a of the bus bar 12 is different from the area of ​​the cross section perpendicular to the direction of current flow in the resistor portion 131b of the bus bar 12. Thus, even when the resistor portions 131a and 131b are part of the bus bar 12, the resistance value of the resistor portion 131a and the resistance value of the resistor portion 131b can be set to different values. For example, Figure 7 and Figure 8As shown, it can be seen that the cross-sectional area of ​​the resistor portion 131a ( Figure 8 The area of ​​the cross section BB′ of the resistor portion 131b is smaller than the area of ​​the cross section of the resistor portion 131b ( Figure 8 The resistance value of the resistor portion 131a is greater than the resistance value of the resistor portion 131b.

[0077] In the fourth example, the cutter 11 of the active fuse 10 has two cutting blades 11c and 11d. When the ignition control circuit 24 outputs the ignition signal S3 to the ignition terminal 11a, the cutter 11 momentarily presses the cutting blades 11c and 11d downward to cut the bus bar 12. For example, the resistors 131a and 131b are the cut portions cut by the cutter 11.

[0078] The cross-sectional area of ​​the cut-off portion of the bus bar 12 cut by the active fuse 10 is smaller (e.g., contracted) than other portions of the bus bar 12 to facilitate cutting. Therefore, the resistance value of the cut-off portion of the bus bar 12 is higher than that of other portions of the bus bar 12. Therefore, the cut-off portion can be used as the resistors 131a and 131b for detecting the current flowing through the bus bar 12, and the structure of the DC short-circuit protection device 1 can be simplified and the cost can be reduced compared to the case where a resistor for detecting the current flowing through the bus bar 12 is separately prepared.

[0079] Furthermore, when the cut portions of the bus bar 12 are processed as the resistors 131a and 131b, the resistance values ​​vary due to the dimensional tolerance caused by the processing accuracy of the cut portions. Therefore, the calibration value of each individual may be stored in a flash memory of the cut-off control circuit 20, and the current value of each individual may be corrected using the calibration value.

[0080] In the fourth example, the active fuse 10 may further include a current detection unit. The two or more current detection units included in the active fuse 10 may include a current detection unit in which the resistance unit is a part of the bus bar 12 and a current detection unit in which the resistance unit is a resistor element.

[0081] In the fourth example, the cut portions of the bus bar 12 are used as the resistors 131 a and 131 b , but portions that are not cut portions and have a reduced cross-sectional area may be used as resistors in the current detection section.

[0082] Furthermore, in the fourth example, the bus bar 12 may be provided with a temperature monitoring terminal 140 .

[0083] (Fifth Example)

[0084] Next, use Fig. 9 A fifth example of the DC short-circuit protection device 1 will be described.

[0085] Fig. 9 is a top view of the bus bar 12 in the fifth example. Fig. 9 In the figure, the current monitoring terminal is omitted.

[0086] In the fifth example, the shape of the resistor portion (cut portion) of the bus bar is different from that of the fourth example. Other points are the same as those of the fourth example, and thus description thereof is omitted.

[0087] When the cut portion of the bus bar 12 is treated as a resistor, the resistance value of the resistor varies due to the dimensional tolerance of the cut portion. Fig. 9 As shown, the resistor portion (cut-off portion) is formed to have a constant cross-sectional shape and a thickness of several millimeters along the direction of current flow, thereby enabling stable current detection even if there is variation in resistance value due to processing accuracy.

[0088] (Other embodiments)

[0089] As described above, the embodiments have been described as examples of the technology of the present disclosure. However, the technology of the present disclosure is not limited thereto, and can also be applied to embodiments that are appropriately changed, replaced, added, omitted, etc. For example, the following modified examples are also included in one embodiment of the present disclosure.

[0090] For example, in the above embodiment, the DC short-circuit protection device 1 (specifically, the disconnection control circuit 20 ) includes the comparison unit 23 , but the DC short-circuit protection device 1 may not include the comparison unit 23 .

[0091] For example, in the above embodiment, the DC short-circuit protection device 1 includes the disconnection control circuit 20, but the disconnection control circuit 20 may not be provided in the DC short-circuit protection device 1. That is, the disconnection control circuit 20 may be provided separately from the DC short-circuit protection device 1.

[0092] For example, in the above-described embodiment, an example is described in which the current detection units 13 a and 13 b each have a current monitoring terminal, but the current monitoring terminal may not be a component of the current detection units 13 a and 13 b.

[0093] In addition, various modifications that can be conceived by those skilled in the art to the embodiments and arbitrarily combining components and functions in the embodiments within the scope not departing from the gist of the present disclosure are also included in the present disclosure.

[0094] (Summarize)

[0095] The first mode of the DC short-circuit protection device 1 disclosed in the present invention comprises: an active fuse 10 having a bus bar 12, which cuts off the bus bar 12 in response to an ignition signal S3; a current detection unit 13a having a resistor unit 131a, which detects the current flowing through the bus bar 12; a current detection unit 13b having a resistor unit 131b, which detects the current flowing through the bus bar 12; and a circuit breaker control circuit 20, which outputs an ignition signal S3 to the active fuse 10 based on a detection signal S1 output from the current detection unit 13a and a detection signal S2 output from the current detection unit 13b, wherein the resistor unit 131a and the resistor unit 131b are integrated with the bus bar 12 in such a way that a current having the same magnitude as the current flowing through the bus bar 12 flows through the resistor unit 131a, and the resistance value of the resistor unit 131b is different from the resistance value of the resistor unit 131b.

[0096] According to the above configuration, it is possible to suppress erroneous disconnection due to the influence of the inductance component.

[0097] In the DC short-circuit protection device 1 of the second mode of the present disclosure, the circuit breaking control circuit 20 performs a predetermined operation based on the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b, thereby determining whether to cut off the bus bar 12. When it is determined that the bus bar 12 is cut off, an ignition signal S3 is output to the active fuse 10.

[0098] According to the above configuration, it is possible to suppress erroneous disconnection due to the influence of the inductance component.

[0099] In the third aspect of the DC short-circuit protection device 1 of the present disclosure, the predetermined operation includes dividing the difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b by the difference between the resistance values ​​of the resistor 131a and the resistor 131b.

[0100] According to the above configuration, it is possible to suppress erroneous disconnection due to the influence of the inductance component.

[0101] In the DC short-circuit protection device 1 of the fourth embodiment of the present disclosure, the resistor portion 131a and the resistor portion 131b are part of the bus bar 12, and the direction of the current flowing through the resistor portion 131a, the resistor portion 131b and the bus bar 12 is taken as the first direction, and the area of ​​the cross section of the resistor portion 131a orthogonal to the first direction (for example Figure 8 The area of ​​the cross section taken along the line BB′ shown in FIG. 1 ) and the area of ​​the cross section of the resistor portion 131 b perpendicular to the first direction (eg Figure 8 The area of ​​the cross section DD′ shown in FIG. 1 is smaller than the cross section area of ​​the portion other than the resistor portion 131a and the resistor portion 131b in the bus bar perpendicular to the first direction (for example, Figure 8 The area of ​​the AA′ section and the area of ​​the CC′ section).

[0102] According to the above configuration, current monitoring terminals are connected to both ends of the portion where the cross-sectional area is reduced, and a voltage generated by current flowing through the portion can be obtained through the current monitoring terminals, thereby enabling the portion to be used as a current detection unit.

[0103] In the DC short-circuit protection device 1 of the fifth aspect of the present disclosure, the cross-sectional area of ​​the resistor portion 131a perpendicular to the first direction (for example Figure 8 The area of ​​the cross section along the BB′ shown in FIG. 1 is different from the area of ​​the cross section of the resistor portion 131 b perpendicular to the first direction (eg, Figure 8 The area of ​​the DD′ section shown).

[0104] According to the above configuration, current monitoring terminals are connected to both ends of the portion where the cross-sectional area is reduced, and a voltage generated by current flowing through the portion can be obtained through the current monitoring terminals, thereby enabling the portion to be used as a current detection unit.

[0105] In the DC short-circuit protection device 1 of the sixth aspect of the present disclosure, the current detection unit 13a has current monitoring terminals 132a and 133a for monitoring the current flowing through the resistor 131a, and the current detection unit 13b has current monitoring terminals 132b and 133b for monitoring the current flowing through the resistor 131b.

[0106] According to the above configuration, the voltages generated in the resistor portion 131 a and the resistor portion 131 b can be outputted from the current detection portion 13 a and the current detection portion 13 b as the detection signal S1 and the detection signal S2 , respectively.

[0107] The DC short-circuit protection device 1 according to the seventh aspect of the present disclosure further includes a temperature monitoring terminal provided on the bus bar 12 to monitor the temperature of the bus bar 12 .

[0108] According to the above configuration, the temperature of the bus bar 12 can be monitored, and the temperature of the bus bar 12 can be used for calculation of the current value.

[0109] The DC short-circuit protection device 1 of the eighth embodiment of the present disclosure also has a comparison unit 23, which compares a first current value calculated based on the detection signal S1 output from the current detection unit 13a with a second current value calculated based on the detection signal output from the current detection unit 13b. The comparison unit 23 detects whether a fault has occurred in either the current detection unit 13a or the current detection unit 13b based on the comparison result of the first current value and the second current value.

[0110] According to the above configuration, when the first current value and the second current value are different, it can be determined that a failure has occurred in either the current detection unit 13 a or the current detection unit 13 b .

[0111] Industrial Applicability

[0112] The present disclosure can be applied to a device for interrupting a current flowing through a current path.

[0113] Description of symbols

[0114] 1 DC short circuit protection device

[0115] 10 Active fuse

[0116] 11 Cutting machine

[0117] 11a Ignition terminal

[0118] 11b, 11c, 11d cutting edges

[0119] 12 Bus Bar

[0120] 12a, 12b fastening portion

[0121] 13a, 13b, 13c current detection unit

[0122] 20 Breaker control circuit

[0123] 21 Detection signal acquisition unit

[0124] 22 Breaking judgment unit

[0125] 23 Comparative Department

[0126] 24 Ignition control circuit

[0127] 121 Cut off part

[0128] 131a, 131b, 131c resistors

[0129] 132a, 133a, 132b, 133b Current monitoring terminals

[0130] 140 Temperature monitoring terminal

[0131] S1, S2 detection signal

[0132] S3 ignition signal

Claims

1. A DC short-circuit protection device, comprising: a fuse having a bus bar, the bus bar being cut in response to an ignition signal; a first current detection unit having a first resistor unit for detecting a current flowing through the bus bar; a second current detection unit having a second resistor unit for detecting a current flowing through the bus bar; as well as a circuit breaker control circuit that outputs the ignition signal to the fuse based on the first detection signal output from the first current detection unit and the second detection signal output from the second current detection unit, The first resistor portion and the second resistor portion are integrated with the bus bar in such a manner that a current having the same magnitude as a current flowing through the bus bar flows therethrough. The resistance value of the first resistor section and the resistance value of the second resistor section are different values.

2. The DC short circuit protection device according to claim 1, wherein: The disconnection control circuit performs a predetermined operation based on a first detection signal output from the first current detection unit and a second detection signal output from the second current detection unit, thereby determining whether to disconnect the bus bar. When it is determined that the bus bar is to be disconnected, the ignition signal is output to the fuse.

3. The DC short circuit protection device according to claim 2, wherein: The predetermined calculation includes a calculation of dividing a difference between the first detection signal output from the first current detection unit and the second detection signal output from the second current detection unit by a difference between a resistance value of the first resistor unit and a resistance value of the second resistor unit.

4. The DC short-circuit protection device according to any one of claims 1 to 3, wherein: The first resistor portion and the second resistor portion are part of the bus bar, The direction of the current flowing through the first resistor portion, the second resistor portion, and the bus bar is defined as a first direction, The cross-sectional area of ​​the first resistor portion and the cross-sectional area of ​​the second resistor portion perpendicular to the first direction are smaller than the cross-sectional area of ​​the bus bar other than the first resistor portion and the second resistor portion perpendicular to the first direction.

5. The DC short circuit protection device according to claim 4, wherein: An area of ​​a cross section of the first resistor portion perpendicular to the first direction is different from an area of ​​a cross section of the second resistor portion perpendicular to the first direction.

6. The DC short-circuit protection device according to any one of claims 1 to 5, wherein: The first current detection unit has a current monitoring terminal for monitoring the current flowing through the first resistor unit. The second current detection unit has a current monitoring terminal for monitoring a current flowing through the second resistance unit.

7. The DC short-circuit protection device according to any one of claims 1 to 6, wherein: The DC short-circuit protection device further includes a temperature monitoring terminal, which is provided on the bus bar and monitors the temperature of the bus bar.

8. The DC short-circuit protection device according to any one of claims 1 to 7, wherein: The DC short-circuit protection device further includes a comparison unit that compares a first current value calculated based on a first detection signal output from the first current detection unit and a second current value calculated based on a second detection signal output from the second current detection unit. The comparison unit detects whether a failure occurs in either the first current detection unit or the second current detection unit based on a comparison result between the first current value and the second current value.

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