Arc detection devices, power conditioners, indoor wiring systems, circuit breakers, solar panels, solar panel accessory modules, and junction boxes

Abstract

The arc detection device (10a) comprises: a low impedance circuit (11) connected between a node (N1) on a wiring (110) and a node (N2) on a wiring (120), wherein the wiring (110) connects the positive electrode of a DC / DC converter (61) to a plurality of DC / DC converters (51, 52, and 53) and branches from the positive electrode of the DC / DC converter (61) to each of the plurality of DC / DC converters (51, 52, and 53), and the wiring ( 120) connecting the negative electrode of the DC / DC converter (61) to a plurality of DC / DC converters (51, 52, and 53), and branching from the negative electrode of the DC / DC converter (61) to each of the plurality of DC / DC converters (51, 52, and 53); a current detection unit (20a) detecting the current flowing in the low-impedance circuit (11); and an arc determination unit (30) determining the occurrence of an arc based on the current detected by the current detection unit (20a).

Description

Technical Field

[0001] The present invention relates to an arc detection device, a power regulator, an indoor wiring system, a circuit breaker, a solar panel, a solar panel accessory module and a connection box. Background Art

[0002] Conventionally, systems are known that convert DC power supplied via wiring from photovoltaic (PV) panels (solar panels) and other sources into AC power using devices such as inverters. Such wiring has been reported to become damaged or broken due to external factors or aging. This damage to the wiring can sometimes cause arcing (i.e., arc discharge). Therefore, arc detection units for detecting arcs have been proposed (e.g., Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-7765 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] Imagine a scenario where multiple devices are installed within a single system, and power is supplied from a single DC power supply via wiring that branches off to each device (called branch wiring). In this scenario, arcs could potentially occur in both the pre-branching and post-branching paths of the branch wiring. While arc detection units could be installed separately for both the pre-branching and post-branching paths, this would increase the system size and cost.

[0008] Therefore, the present invention provides an arc detection device and the like that can easily detect an arc generated in a branch wiring.

[0009] Solutions for solving problems

[0010] One embodiment of the arc detection device involved in the present invention includes: a low-impedance circuit, which is connected between a first node on a first wiring and a second node on a second wiring, the first wiring connects the positive pole of a DC power supply to a plurality of devices and branches from the positive pole of the DC power supply to each of the plurality of devices, the second wiring connects the negative pole of the DC power supply to the plurality of devices and branches from the negative pole of the DC power supply to each of the plurality of devices, and the impedance of the low-impedance circuit is lower than the impedance of each of the plurality of devices; a current detection unit, which detects the current flowing in the low-impedance circuit; and an arc determination unit, which determines the occurrence of an arc based on the current detected by the current detection unit.

[0011] One embodiment of a power conditioner according to the present invention includes the arc detection device described above and a converter that converts output power of the DC power supply.

[0012] One aspect of an indoor wiring system according to the present invention includes the arc detection device described above, the first wiring, the second wiring, and the plurality of devices installed indoors.

[0013] One aspect of a circuit breaker according to the present invention includes the arc detection device described above, and when it is determined that an arc has occurred, the circuit breaker interrupts the current flowing through the first wiring and the second wiring.

[0014] One aspect of the present invention provides a solar panel that generates electricity using solar energy, including the arc detection device described above.

[0015] One aspect of the present invention includes a solar panel accessory module that converts a signal output from a solar panel, and includes the arc detection device described above.

[0016] One embodiment of a connection box according to the present invention includes the above-mentioned arc detection device, and the connection box connects a solar panel and a power conditioner.

[0017] Effects of the Invention

[0018] According to one aspect of the present invention, an arc generated in a branch wiring can be easily detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a configuration diagram showing an example of a solar power generation system according to the first embodiment.

[0020] Figure 2A 3 is a diagram showing a spectrum of a current flowing through point A1 when an arc occurs at point A1.

[0021] Figure 2B1 is a diagram showing a spectrum of a current flowing through a point A2 when an arc occurs at a point A1.

[0022] Figure 2C 1 is a diagram showing the frequency spectrum of the current flowing through points A3 and A4 when an arc occurs at point A1.

[0023] Figure 3 This is a configuration diagram showing an example of a solar power generation system according to Modification 1 of Embodiment 1.

[0024] Figure 4 This is a configuration diagram showing an example of a solar power generation system according to Modification 2 of Embodiment 1.

[0025] Figure 5 This is a configuration diagram showing an example of an indoor wiring system according to the second embodiment.

[0026] Figure 6 It is a diagram for explaining an application example of the arc detection device according to the present invention. DETAILED DESCRIPTION

[0027] The following describes embodiments of the present invention with reference to the accompanying drawings. Each embodiment described below represents a specific example of the present invention. Therefore, the numerical values, shapes, materials, components, and the configuration and connection methods of the components shown in the following embodiments are examples and are not intended to limit the present invention.

[0028] In addition, each figure is a schematic diagram and does not necessarily illustrate the diagram strictly. In addition, in each figure, the same reference numerals are attached to substantially the same structure and repeated descriptions are omitted or simplified.

[0029] (Implementation Method 1)

[0030] Figure 1 This is a configuration diagram showing an example of a solar power generation system 1 a according to the first embodiment.

[0031] The solar power generation system 1 a includes a solar panel 41 , batteries 54 , 55 , and 56 , DC / DC converters 51 , 52 , and 53 , and a power conditioner 60 a .

[0032] The solar panel 41 generates DC power by utilizing solar energy. The DC power generated by the solar panel 41 is supplied to the power conditioner 60a.

[0033] Battery 54 stores DC power from DC / DC converter 51, battery 55 stores DC power from DC / DC converter 52, and battery 56 stores DC power from DC / DC converter 53. For example, batteries 54, 55, and 56 can be installed in electric vehicles, electric bicycles, and the like, or can be used to supply power to household electrical appliances and the like.

[0034] DC / DC converters 51, 52, and 53 are voltage converters that step up or down the DC voltage of the supplied DC power and output it. DC / DC converter 51 steps up or down the DC power supplied from power conditioner 60a and outputs it to battery 54. DC / DC converter 52 steps up or down the DC power supplied from power conditioner 60a and outputs it to battery 55. DC / DC converter 53 steps up or down the DC power supplied from power conditioner 60a and outputs it to battery 56.

[0035] The power conditioner 60a converts the DC power supplied from the solar panel 41 into AC power. Furthermore, the power conditioner 60a supplies the DC power supplied from the solar panel 41 to a battery, etc., without converting it into AC power. The power conditioner 60a includes a DC / DC converter 61, an inverter 62, and an arc detection device 10a.

[0036] DC / DC converter 61 steps up or steps down the DC power supplied from solar panel 41 and outputs it to DC / DC converters 51, 52, and 53 and inverter 62. Since DC power is output from DC / DC converter 61, it can be considered a DC power supply. In other words, DC / DC converter 61 is an example of a DC power supply. DC / DC converter 61 has a positive electrode and a negative electrode. The positive electrode is connected to wiring 110, and the negative electrode is connected to wiring 120.

[0037] Wiring 110 and 120 connects DC / DC converter 61 to DC / DC converters 51, 52, and 53. Wiring 110 is an example of first wiring that connects the positive terminal of DC / DC converter 61 to multiple devices. Wiring 120 is an example of second wiring that connects the negative terminal of DC / DC converter 61 to multiple devices. DC / DC converters 51, 52, and 53 are examples of multiple devices connected to DC / DC converter 61 via wiring 110 and 120.

[0038] Wiring 110 branches from the positive electrode of DC / DC converter 61 to each of DC / DC converters 51, 52, and 53. The point in wiring 110 where wiring 110 branches from the positive electrode of DC / DC converter 61 to DC / DC converters 51, 52, and 53 is referred to as branch point N3.

[0039] In the wiring 110 , a first pre-branch path, which is a path before branching connecting the branch point N3 and the positive electrode of the DC / DC converter 61 , is referred to as a path 110 a .

[0040] Wiring 110 has a plurality of first branched paths connecting branch point N3 to each of DC / DC converters 51, 52, and 53. In wiring 110, the first branched path connecting branch point N3 to DC / DC converter 51 is path 110c, the first branched path connecting branch point N3 to DC / DC converter 52 is path 110d, and the first branched path connecting branch point N3 to DC / DC converter 53 is path 110b.

[0041] Wiring 120 branches from the negative electrode of DC / DC converter 61 to each of DC / DC converters 51, 52, and 53. The point in wiring 120 where wiring 120 branches from the negative electrode of DC / DC converter 61 to DC / DC converters 51, 52, and 53 is referred to as branch point N4.

[0042] In the wiring 120 , a second pre-branch path, which is a path before branching connecting the branch point N4 and the negative electrode of the DC / DC converter 61 , is referred to as a path 120 a .

[0043] Wiring 120 has a plurality of second branched paths connecting branch point N4 to each of DC / DC converters 51, 52, and 53. In wiring 120, the second branched path connecting branch point N4 to DC / DC converter 51 is path 120c, the second branched path connecting branch point N4 to DC / DC converter 52 is path 120d, and the second branched path connecting branch point N4 to DC / DC converter 53 is path 120b.

[0044] Inverter 62 converts the DC power supplied from DC / DC converter 61 into AC power for output. Inverter 62 uses, for example, MPPT (Maximum Power Point Tracking) to adjust the current and voltage of the DC power supplied from DC / DC converter 61 to maximize power. For example, inverter 62 converts DC power into AC power with a voltage of 100V and a frequency of 50Hz or 60Hz. This AC power is used in household electrical appliances, etc.

[0045] Wiring 110 and 120 are branched wirings, and arcs may occur in both the pre-branching path and the multiple post-branching paths. While arc detection units can be provided for both the pre-branching path and the multiple post-branching paths, this would increase the system size and cost.

[0046] Therefore, in order to easily detect arcs generated in the branch wirings (here, the wirings 110 and 120 ), the arc detection device 10 a is used.

[0047] The arc detection device 10 a includes a low-impedance circuit 11 , a current detection unit 20 a , and an arc determination unit 30 .

[0048] The low-impedance circuit 11 is a circuit connected between a node N1 on the wiring 110 and a node N2 on the wiring 120. The node N1 is an example of a first node, and the node N2 is an example of a second node. The low-impedance circuit 11 is, for example, a capacitor. The capacitor has a function of cutting off the DC component, so it is possible to extract only the high-frequency component from the signal flowing through the wirings 110 and 120. The capacitance value of the capacitor can be appropriately determined according to the frequency of the high-frequency component to be extracted, etc. The impedance of the low-impedance circuit 11 is lower than the impedance of each of the DC / DC converters 51, 52, and 53. In addition, the impedance of the low-impedance circuit 11 is lower than the impedance of the DC / DC converter 61. As a result, in the wirings 110 and 120, the high-frequency component easily flows to the low-impedance circuit 11. Use Figures 2A to 2C The details will be described later.

[0049] The current detection unit 20a detects the current flowing in the low-impedance circuit 11. For example, the current detection unit 20a detects the current flowing in the low-impedance circuit 11 by detecting the current flowing in the path connecting the node N1 and the node N2. For example, the current detection unit 20a includes a magnetic core 21, and the path connecting the node N1 and the node N2 passes through the magnetic core 21. The current detection unit 20a detects the current flowing in the path (i.e., the current flowing in the low-impedance circuit 11) based on the magnetic field generated by the magnetic core 21.

[0050] The core 21 is an annular shape (here, a circular ring shape) through which wiring can pass, and uses the current flowing through the wiring through its holes to generate a magnetic field in the core corresponding to the current. In addition, the core 21 is not limited to a circular ring shape, and can also be a rectangular ring shape.

[0051] The current detection unit 20a includes, for example, a Hall element (not shown) that detects the magnetic field generated by the magnetic core 21 and generates a voltage corresponding to the magnetic field generated by the magnetic core 21. The voltage generated by the Hall element is input to the arc determination unit 30 as a signal representing the magnetic field generated by the magnetic core 21, that is, the current flowing in the path passing through the magnetic core 21.

[0052] Arc detection unit 30 is implemented, for example, by a microcomputer (microcontroller). A microcomputer is a semiconductor integrated circuit that includes a ROM and RAM that store programs, a processor (CPU: Central Processing Unit) that executes the programs, a timer, an A / D converter, and a D / A converter. Alternatively, arc detection unit 30 may be implemented in hardware using dedicated electronic circuits composed of an A / D converter, a logic circuit, a gate array, and a D / A converter.

[0053] The arc detection unit 30 determines the occurrence of an arc based on the current detected by the current detection unit 20a. For example, the arc detection unit 30 determines the occurrence of an arc in the wiring 110 or 120 by performing frequency analysis on the current detected by the current detection unit 20a. The current superimposed with the high-frequency component generated by the arc includes a frequency component caused by the arc, and the occurrence of an arc can be determined by detecting this frequency component. If the arc detection unit 30 determines that an arc has occurred, it can be known that the arc has occurred somewhere in the wiring 110 or 120. In other words, the occurrence of an arc in the branch wiring (here, the wiring 110 and 120) can be detected using only one current detection unit 20a (e.g., the magnetic core 21).

[0054] For example, using Figures 2A to 2C The following describes a case where, when an arc occurs at point A1 in the wiring 110 , a high-frequency component generated by the arc easily flows into the low-impedance circuit 11 .

[0055] Figure 2A 1 is a diagram showing the spectrum of the current flowing through point A1 when an arc occurs at point A1. Point A1 is a point on path 110c. Specifically, point A1 is a point on path 110c that connects power conditioner 60a and DC / DC converter 51.

[0056] Figure 2B1 is a diagram showing the spectrum of the current flowing through point A2 when an arc occurs at point A1. Point A2 is a point on the path connecting node N1 and node N2. That is, the current flowing through point A2 is the current flowing through low-impedance circuit 11.

[0057] Figure 2C 110d is a diagram showing the spectrum of current flowing through points A3 and A4 when an arc occurs at point A1. Point A3 is a point on the path 110d, and point A4 is a point on the path 110b.

[0058] Since an arc is generated at point A1, the following is measured at point A1: Figure 2A The frequency spectrum of the current shown is superimposed with the high-frequency component generated by the arc.

[0059] like Figure 2B As shown, the same value as that in Figure 2A The frequency spectrum of the current superimposed with the high-frequency component generated by the arc is the same as that shown. This is because the high-frequency component caused by the arc generated at point A1 flows to the path 110a at the branch point N3 and flows to the low-impedance circuit 11 at the node N1.

[0060] On the other hand, Figure 2C As shown, no such Figure 2A The frequency spectrum of the current shown here is superimposed with high-frequency components generated by the arc. This is because the impedance of DC / DC converters 52 and 53 is higher than the impedance of low-impedance circuit 11, and the high-frequency components are less likely to flow into paths 110d and 110b at branch point N3.

[0061] Thus, it can be seen that the high-frequency component generated by the arc generated at point A1 flows to the low-impedance circuit 11 having low impedance and hardly flows to the DC / DC converters 52 , 53 , and 61 having high impedance.

[0062] For example, even if an arc occurs in another branched path, the high-frequency component generated by the arc is unlikely to flow to the DC / DC converter having high impedance, but is likely to flow to the low-impedance circuit 11 having low impedance.

[0063] In addition, although the example in which node N1 is a node on path 110a and node N2 is a node on path 110b is described, in embodiment 1, node N1 can also be a node on path 110b, 110c or 110d, and node N2 can also be a node on path 120b, 120c or 120d.

[0064] As described above, the arc detection device 10a according to this embodiment includes: a low-impedance circuit 11 connected between a first node (e.g., node N1) on a first wiring line (e.g., wiring line 110) that connects the positive electrode of a DC power supply (e.g., DC / DC converter 61) to a plurality of devices and branches from the positive electrode of the DC power supply to each of the plurality of devices; and a second node (e.g., node N2) on a second wiring line (e.g., wiring line 120) that connects the negative electrode of the DC power supply to a plurality of devices and branches from the negative electrode of the DC power supply to each of the plurality of devices, wherein the impedance of the low-impedance circuit 11 is lower than the impedance of each of the plurality of devices (e.g., DC / DC converters 51, 52, and 53); a current detection unit 20a that detects a current flowing in the low-impedance circuit 11; and an arc determination unit 30 that determines the occurrence of an arc based on the current detected by the current detection unit 20a.

[0065] Consequently, regardless of whether an arc occurs in any of the paths before and after the branching of the first and second wiring lines (e.g., paths 110a, 110b, 110c, 110d, 120a, 120b, 120c, and 120d), the high-frequency components generated by the arc flow into the low-impedance circuit 11, which has an impedance lower than the impedance of each of the multiple devices. Therefore, arc detection can be performed based on the current detected by the current detection unit 20a, which detects the current flowing in the low-impedance circuit 11. In other words, arcs generated in the branch wiring can be detected without providing separate arc detection units for the path before and after the branching of the branch wiring. This allows for easy detection of arcs generated in the branch wiring using a single current detection unit 20a, without increasing the size or cost of the system. For example, when an arc is detected, the DC / DC converter 61 and the inverter 62 can be stopped based on the detection result, or a circuit breaker (not shown) provided in each wiring can be operated to cut off the current flowing in each wiring.

[0066] For example, the current detection unit 20 a may detect the current flowing in the low-impedance circuit 11 by detecting the current flowing in the path connecting the first node and the second node.

[0067] This allows the current detection unit 20 a to easily detect the current flowing through the low-impedance circuit 11 provided on the path connecting the first node and the second node.

[0068] The power conditioner 60a according to the present embodiment includes the arc detection device 10a and a converter (for example, an inverter 62) that converts output power of a DC power supply.

[0069] According to this, it is possible to provide the power conditioner 60a that can easily detect an arc generated in the branch wiring.

[0070] (Variation 1 of Implementation Example 1)

[0071] In the first modification of the first embodiment, an example is described in which the current detection unit detects the current flowing through the path 110 a or 120 a which is the pre-branch path.

[0072] Figure 3 This is a configuration diagram showing an example of a solar power generation system 1 b according to Modification 1 of Embodiment 1.

[0073] The solar power generation system 1b differs from the solar power generation system 1a according to Embodiment 1 in that the power conditioner 60a is replaced with a power conditioner 60b. Other aspects are the same as those of Embodiment 1, and therefore their description is omitted.

[0074] The power conditioner 60b converts the DC power supplied from the solar panel 41 into AC power. Furthermore, the power conditioner 60b supplies the DC power supplied from the solar panel 41 to a battery, etc., without converting it to AC power. The power conditioner 60b differs from the power conditioner 60a of Embodiment 1 in that it does not include the arc detection device 10a but instead includes the arc detection device 10b. Since other aspects are the same as those of Embodiment 1, their description will be omitted.

[0075] Arc detection device 10b includes low impedance circuit 11, current detection unit 20b, and arc determination unit 30. Since low impedance circuit 11 and arc determination unit 30 correspond to those in Embodiment 1, their description is omitted.

[0076] The current detection unit 20b detects the current flowing in the low-impedance circuit 11. For example, the current detection unit 20b detects the current flowing in the low-impedance circuit 11 by detecting the current flowing in the path 110a or 120a. Specifically, the current detection unit 20b detects the current flowing in the path connecting the node N1 and the branch point N3 in the path 110a, or the path connecting the node N2 and the branch point N4 in the path 120a. Here, for example, the current detection unit 20b includes a magnetic core 21, and the path 110a (specifically, the path connecting the node N1 and the branch point N3 in the path 110a) passes through the magnetic core 21. The current detection unit 20b detects the current flowing in the path (i.e., the current flowing in the low-impedance circuit 11) based on the magnetic field generated by the magnetic core 21.

[0077] For example, using Figures 2A to 2CTo illustrate the following situation: When an arc occurs at point B1 in wiring 110, the high-frequency component generated by the arc easily flows to the low-impedance circuit 11, and the arc can be detected by detecting the current flowing in the path 110a. Figures 2A to 2C Point A1 is renamed as point B1, point A2 is renamed as point B2, point A3 is renamed as point B3, and point A4 is renamed as point B4.

[0078] Point B1 is a point on path 110c. Specifically, point B1 is a point on path 110c that connects power conditioner 60b and DC / DC converter 51. Point B2 is a point on path 110a that connects node N1 and branch point N3. Point B3 is a point on path 110d, and point B4 is a point on path 110b.

[0079] Since an arc is generated at point B1, the following is measured at point B1: Figure 2A The frequency spectrum of the current shown is superimposed with the high-frequency component generated by the arc.

[0080] like Figure 2B As shown, the same value as that in Figure 2A The frequency spectrum of the current superimposed with the high-frequency component generated by the arc is the same as the frequency spectrum shown. This is because the high-frequency component caused by the arc generated at point B1 flows to the path 110a at the branch point N3, passes through point B2, and then flows to the low-impedance circuit 11 at the node N1.

[0081] On the other hand, Figure 2C As shown, no ions were measured at points B3 and B4. Figure 2A The frequency spectrum of the current shown here is superimposed with high-frequency components generated by the arc. This is because the impedance of DC / DC converters 52 and 53 is higher than the impedance of low-impedance circuit 11, and the high-frequency components are less likely to flow into paths 110d and 110b at branch point N3.

[0082] Thus, it can be seen that the high-frequency component generated by the arc generated at point B1 flows to the low-impedance circuit 11 with low impedance and is less likely to flow to the high-impedance DC / DC converters 52, 53, and 61. Furthermore, it can be seen that the arc can be detected by detecting the current flowing in path 110a (specifically, the path connecting node N1 and branch point N3 in path 110a).

[0083] For example, even if an arc occurs in another branched path, the high-frequency component generated by the arc is unlikely to flow to the DC / DC converter having high impedance, but is likely to flow to the low-impedance circuit 11 having low impedance.

[0084] In variant 1 of embodiment 1, arcs generated in the path 110a connecting node N1 and branch point N3, path 110b, 110c, or 110d, or the path 120a connecting node N2 and branch point N4, path 120b, 120c, or 120d can be detected.

[0085] In the first embodiment, it was explained that node N1 could be a node on path 110b, 110c, or 110d, and node N2 could be a node on path 120b, 120c, or 120d. However, in the first variation of the first embodiment, node N1 is required to be a node on path 110a, and node N2 is required to be a node on path 120a. This is because high-frequency components must flow through path 110a or path 120a, where the current is detected by current detection unit 20b.

[0086] As described above, the first node (e.g., node N1) is a node on a first pre-branch path (e.g., path 110a) in the first wiring (e.g., wiring 110) that connects the branch point N3, which branches from the positive electrode of the DC power supply (e.g., DC / DC converter 61) to each of the multiple devices (e.g., DC / DC converters 51, 52, and 53), to the positive electrode of the DC power supply. The second node (e.g., node N2) is a node on a second pre-branch path (e.g., path 120a) in the second wiring (e.g., wiring 120) that connects the branch point N4, which branches from the negative electrode of the DC power supply to each of the multiple devices, to the negative electrode of the DC power supply. The current detection unit 20b detects the current flowing in the low-impedance circuit 11 by detecting the current flowing in the first pre-branch path or the second pre-branch path.

[0087] In this way, the current detection unit 20 b can also detect the current flowing in the low-impedance circuit 11 by detecting the current flowing in the first pre-branch path or the second pre-branch path.

[0088] (Variation 2 of Implementation 1)

[0089] In the second modification of the first embodiment, an example is described in which the current detection unit detects the current flowing through the path 110 b , 110 c , 110 d , 120 b , 120 c , or 120 d , which is a branched path.

[0090] Figure 4 This is a configuration diagram showing an example of a solar power generation system 1 c according to Modification 2 of Embodiment 1.

[0091] The solar power generation system 1c differs from the solar power generation system 1a according to Embodiment 1 in that the power conditioner 60a is replaced with a power conditioner 60c. Other aspects are the same as those of Embodiment 1, and therefore description thereof will be omitted.

[0092] The power conditioner 60c converts the DC power supplied from the solar panel 41 into AC power. Furthermore, the power conditioner 60c supplies the DC power supplied from the solar panel 41 to a battery, etc., without converting it to AC power. The power conditioner 60c differs from the power conditioner 60a of Embodiment 1 in that it does not include the arc detection device 10a but instead includes an arc detection device 10c. Since other aspects are the same as those of Embodiment 1, their description will be omitted.

[0093] Arc detection device 10c includes low impedance circuit 11, current detection unit 20c, and arc determination unit 30. Since low impedance circuit 11 and arc determination unit 30 correspond to those in Embodiment 1, their description is omitted.

[0094] Current detection unit 20c detects the current flowing in low-impedance circuit 11. For example, current detection unit 20c detects the current flowing in low-impedance circuit 11 by detecting the current flowing in one of the first branched path and the second branched path corresponding to each of DC / DC converters 51, 52, and 53. Specifically, current detection unit 20c detects the current flowing in one of paths 110c and 120c corresponding to DC / DC converter 51, the current flowing in one of paths 110d and 120d corresponding to DC / DC converter 52, and the current flowing in one of paths 110b and 120b corresponding to DC / DC converter 53. Here, for example, the current detection unit 20c has a magnetic core 21, and the paths 110c, 110d and 120b of one of the first branch post-path and the second branch post-path corresponding to each of the DC / DC converters 51, 52 and 53 respectively pass through the magnetic core 21. The current detection unit 20c detects the current flowing in the paths 110c, 110d and 120b (that is, the current flowing in the low impedance circuit 11) based on the magnetic field generated by the magnetic core 21.

[0095] For example, using Figures 2A to 2C To illustrate the following situation: when an arc occurs at point C1 in wiring 110, the high-frequency component generated by the arc easily flows to low-impedance circuit 11, and the arc can be detected by detecting the current flowing in paths 110c, 110d, and 120b at the same time. Figures 2A to 2CPoint A1 is renamed as point C1, point A2 is renamed as point C2, point A3 is renamed as point C3, and point A4 is renamed as point C4.

[0096] Point C1 is a point on path 110c. Specifically, point C1 is a point on the path connecting power conditioner 60c and DC / DC converter 51 within path 110c. Point C2 is a point on path 110c (specifically, path 110c within power conditioner 60c). Point C3 is a point on path 110d, and point C4 is a point on path 110b.

[0097] Since an arc is generated at point C1, the following is measured at point C1: Figure 2A The frequency spectrum of the current shown is superimposed with the high-frequency component generated by the arc.

[0098] like Figure 2B As shown, the same value as that in Figure 2A The spectrum of the current superimposed with the high-frequency component generated by the arc is the same as the spectrum shown. This is because the high-frequency component caused by the arc generated at point C1 passes through point C2, flows to path 110a at branch point N3, and flows to low-impedance circuit 11 at node N1.

[0099] On the other hand, Figure 2C As shown, no signal was measured at points C3 and C4. Figure 2A The frequency spectrum of the current shown here is superimposed with high-frequency components generated by the arc. This is because the impedance of DC / DC converters 52 and 53 is higher than the impedance of low-impedance circuit 11, and the high-frequency components are less likely to flow into paths 110d and 110b at branch point N3.

[0100] Thus, it can be seen that the high-frequency component generated by the arc generated at point C1 flows to the low-impedance circuit 11 with low impedance and is less likely to flow to the high-impedance DC / DC converters 52, 53, and 61. Furthermore, it can be seen that the arc can be detected by simultaneously detecting the currents flowing through paths 110c, 110d, and 120b.

[0101] For example, even if an arc occurs in another branched path, the high-frequency component generated by the arc is unlikely to flow to the DC / DC converter having high impedance, but is likely to flow to the low-impedance circuit 11 having low impedance.

[0102] For example, the path corresponding to each of DC / DC converters 51, 52, and 53 includes at least one first branched path and at least one second branched path. Here, the path corresponding to each of DC / DC converters 51, 52, and 53 includes paths 110c and 110d as at least one first branched path and path 120b as at least one second branched path.

[0103] In variant example 2 of embodiment 1, arcs generated in the path 110a connecting node N1 and branch point N3, path 110b, 110c, or 110d, or the path 120a connecting node N2 and branch point N4, path 120b, 120c, or 120d can be detected.

[0104] In the second modification of the first embodiment, similar to the first embodiment, the node N1 may be a node on the path 110b, 110c, or 110d, and the node N2 may be a node on the path 120b, 120c, or 120d.

[0105] As described above, the first wiring (e.g., wiring 110) includes a plurality of first branched paths (e.g., paths 110b, 110c, and 110d) connecting the branch point N3 where the first wiring branches from the positive electrode of the DC power supply (e.g., DC / DC converter 61) to each of the plurality of devices (e.g., DC / DC converters 51, 52, and 53) to each of the plurality of devices. The second wiring (e.g., wiring 120) includes a plurality of second branched paths (e.g., paths 120b, 120c, and 120d) connecting the branch point N4 where the second wiring branches from the negative electrode of the DC power supply to each of the plurality of devices to each of the plurality of devices. The current detection unit 20c has a magnetic core 21, and the path of one of the first branched post-path and the second branched post-path corresponding to each of the multiple devices passes through the magnetic core 21. The current detection unit 20c detects the current flowing in the above-mentioned path corresponding to each of the multiple devices based on the magnetic field generated by the magnetic core 21, thereby detecting the current flowing in the low-impedance circuit 11.

[0106] In this manner, the current detection unit 20 c can also detect the current flowing in the low impedance circuit 11 by detecting the current flowing in one of the first branched path and the second branched path corresponding to each of the plurality of devices.

[0107] For example, the one path corresponding to each of the plurality of devices may include at least one first branched path and at least one second branched path.

[0108] For example, due to the large DC current flowing through the first branched path and the second branched path, the magnetic core 21 may be magnetically saturated. Therefore, there is a concern that when an arc occurs, the current (high-frequency component) caused by the arc, which is superimposed on the DC current flowing in the first branched path or the second branched path, cannot be accurately detected due to the magnetic saturation caused by the DC current. In contrast, the paths corresponding to the above-mentioned one side of the multiple devices passing through the magnetic core 21 include the first branched path and the second branched path. The directions of the DC currents flowing in the first branched path and the second branched path are opposite to each other, so that the magnetic field caused by the DC current flowing in the first branched path and the magnetic field caused by the DC current flowing in the second branched path can be offset, thereby preventing magnetic saturation. Therefore, the arc generated in the branch wiring can be accurately detected.

[0109] (Implementation Method 2)

[0110] In the first embodiment, an example in which the arc detection device is provided in the solar power generation system (specifically, the power conditioner) is described, but the arc detection device may also be provided in the indoor wiring system. Figure 5 Let's explain this.

[0111] Figure 5 : is a structural diagram showing an example of an indoor wiring system 2 according to Embodiment 2. Figure 5 Also shown is a system power supply 43 connected to the indoor wiring system 2.

[0112] The system power supply 43 is a power source that supplies AC power generated by a power plant or the like.

[0113] Indoor wiring system 2 includes AC / DC converter 42, wiring 111 and 121, lighting fixtures 57, 58, and 59, and arc detection device 10. AC / DC converter 42, wiring 111 and 121, lighting fixtures 57, 58, and 59, and arc detection device 10 are installed indoors in a facility such as a house, apartment building, building, or factory.

[0114] The AC / DC converter 42 is a power converter that receives AC power from the system power supply 43, converts the supplied AC power into DC power, and outputs the converted DC power. Since the AC / DC converter 42 outputs DC power, it can be regarded as a DC power source.

[0115] AC / DC converter 42 converts AC power supplied from system power supply 43 into DC power and outputs the DC power to lighting fixtures 57, 58, and 59. AC / DC converter 42 has a positive electrode and a negative electrode. The positive electrode is connected to wiring 111, and the negative electrode is connected to wiring 121.

[0116] Wiring 111 and 121 connects AC / DC converter 42 to lighting fixtures 57, 58, and 59. Wiring 111 is an example of first wiring that connects the positive terminal of AC / DC converter 42 to multiple devices. Wiring 121 is an example of second wiring that connects the negative terminal of AC / DC converter 42 to multiple devices. Lighting fixtures 57, 58, and 59 are examples of multiple devices connected to AC / DC converter 42 via wiring 111 and 121, respectively.

[0117] Wiring 111 is the same as wiring 110 in Embodiment 1 and is a wiring that branches from the positive electrode of AC / DC converter 42 to each of lighting fixtures 57, 58, and 59. Wiring 121 is the same as wiring 120 in Embodiment 1 and is a wiring that branches from the negative electrode of AC / DC converter 42 to each of lighting fixtures 57, 58, and 59.

[0118] Furthermore, the plurality of devices are not limited to lighting fixtures, and any device installed indoors is not particularly limited. For example, the plurality of devices may be speakers or microphones.

[0119] Wiring 111 and 121 are branched wirings, and arcs may occur in both the pre-branching path and the multiple post-branching paths. While arc detection units can be provided for both the pre-branching path and the multiple post-branching paths, this would increase the system size and cost.

[0120] Therefore, in order to easily detect arcs generated in the branch wirings (here, the wirings 111 and 121 ), the arc detection device 10 is used.

[0121] The arc detection device 10 includes a low-impedance circuit 11 , a current detection unit 20 , and an arc determination unit 30 .

[0122] The low impedance circuit 11 is a circuit connected between a first node on the wiring 111 and a second node on the wiring 121. The low impedance circuit 11 has the same function as that of the low impedance circuit in the first embodiment, and therefore description thereof will be omitted.

[0123] The current detection unit 20 detects the current flowing in the low-impedance circuit 11. For example, the current detection unit 20 detects the current flowing in the low-impedance circuit 11 by detecting the current flowing in the path connecting the first node on the wiring 111 and the second node on the wiring 121. For example, the current detection unit 20 includes a magnetic core 21 that passes through the path connecting the first node on the wiring 111 and the second node on the wiring 121. The current detection unit 20 detects the current flowing in the path (i.e., the current flowing in the low-impedance circuit 11) based on the magnetic field generated by the magnetic core 21. Alternatively, the current detection unit 20 can detect the current in the path before the branching of the branched wiring, as in Modification 1 of Embodiment 1, or detect the current in the path after the branching, as in Modification 2 of Embodiment 1.

[0124] The arc determination unit 30 determines the occurrence of an arc based on the current detected by the current detection unit 20. The arc determination unit 30 has the same function as the arc determination unit in the first embodiment, and therefore, description thereof will be omitted.

[0125] In the indoor wiring system 2 , high-frequency components generated by arcing in the wiring 111 or 121 also tend to flow into the low-impedance circuit 11 .

[0126] As described above, the indoor wiring system 2 according to this embodiment includes the arc detection device 10 , first wiring (eg, wiring 111 ), second wiring (eg, wiring 121 ), and a plurality of devices installed indoors (eg, lighting fixtures 57 , 58 , and 59 ).

[0127] In this manner, the arc detection device 10 can also be applied to the indoor wiring system 2, and the indoor wiring system 2 that can easily detect an arc generated in the branch wiring can be provided.

[0128] (Other embodiments)

[0129] As mentioned above, the arc detection device and the like according to the embodiment have been described, but the present invention is not limited to the above-described embodiment.

[0130] For example, the structure of the current detection unit is not limited to the structure having the magnetic core 21. For example, the current detection unit may also be a structure having a resistor element having a small resistance value. This is because the potential difference generated by the current flowing through the resistor element becomes a value corresponding to the current flowing through the resistor element, and the resistor element functions as a current sensor.

[0131] For example, in the above embodiment, the arc detection device is applied to a solar power generation system (specifically, a power conditioner) and an indoor wiring system, but the application examples are not limited to these. Figure 6Another application example of the arc detection device according to the present invention (ie, an arc detection device capable of easily detecting an arc generated in a branch wiring) will be described.

[0132] Figure 6 It is a diagram for explaining an application example of the arc detection device according to the present invention.

[0133] The arc detection device according to the present invention is applied, for example, to various components of a system that converts DC power supplied from a solar panel 310 via wiring into AC power using a power conditioner 500. Here, multiple groups (e.g., three groups) of solar panels, each consisting of multiple (e.g., three) solar panels 310 connected in series via a single wiring 600 (string), are arranged to form a solar cell array 300. The multiple wirings 600 are connected to the power conditioner 500 after being aggregated by a connection box 400. The DC power source is the solar panel 310, the first wiring is the wiring 600 connected to the positive pole of the solar panel 310, and the second wiring is the wiring 600 connected to the negative pole of the solar panel 310. The wiring 600 branches within the power conditioner 500.

[0134] For example, a circuit breaker 410 is provided for each wiring 600. Here, the circuit breaker 410 is provided in the connection box 400. Alternatively, the circuit breaker 410 may not be provided in the connection box 400. For example, the circuit breaker 410 may be provided between the connection box 400 and the solar cell array 300, or may be provided between the connection box 400 and the power conditioner 500 rather than for each wiring 600.

[0135] Solar panel 310, for example, includes a solar panel auxiliary module 320 that converts the signal output from solar panel 310. Solar panel auxiliary module 320 is, for example, a DC / DC converter that optimizes the power generation of each solar panel 310. Alternatively, solar panel 310 may not include solar panel auxiliary module 320.

[0136] For example, the circuit breaker 410 may include an arc detection device. When it is determined that an abnormality has occurred, the circuit breaker 410 interrupts the current flowing through the wiring 600.

[0137] For example, the solar panel 310 or the solar panel auxiliary module 320 may include an arc detection device. When it is determined that an arc has occurred, the solar panel 310 or the solar panel auxiliary module 320 stops outputting power to the wiring 600 .

[0138] Furthermore, for example, the junction box 400 may include an arc detection device. When it is determined that an arc has occurred, the junction box 400 cuts off the current flowing through the wiring 600 using, for example, the circuit breaker 410 or the like.

[0139] Furthermore, the arc detection device according to the present invention is not limited to these, but can be applied to all systems that require arc detection.

[0140] Thus, the circuit breaker 410 may also include an arc detection device to interrupt the current flowing through the first and second wiring lines when an arc is detected. Furthermore, the solar panel 310, which generates electricity using solar energy, may also include an arc detection device. Furthermore, the solar panel accessory module 320, which converts the signal output from the solar panel 310, may also include an arc detection device. Furthermore, the connection box 400, which connects the solar panel 310 to the power conditioner 500, may also include an arc detection device.

[0141] For example, the arc determination unit included in the arc detection device may be implemented as software in a general-purpose computer such as a personal computer.

[0142] Furthermore, the present invention also encompasses various modifications that would occur to those skilled in the art to the various embodiments and any combination of components and functions in the various embodiments without departing from the spirit of the present invention.

[0143] Description of Reference Numerals

[0144] 1a, 1b, 1c: Solar power generation system; 2: Indoor wiring system; 10, 10a, 10b, 10c: Arc detection device; 11: Low-impedance circuit; 20, 20a, 20b, 20c: Current detection unit; 21: Magnetic core; 30: Arc determination unit; 41, 310: Solar panel; 42: AC / DC converter; 43: System power supply; 51, 52, 53, 61: DC / DC converter; 54, 55, 56: Battery; 57, 58, 59: Lighting fixture; 60a, 60b, 60c: c, 500: power conditioner; 62: inverter; 110, 111, 120, 121, 600: wiring; 110a, 110b, 110c, 110d, 120a, 120b, 120c, 120d: path; 300: solar cell array; 320: solar panel accessory module; 400: connection box; 410: circuit breaker; A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3, C4: point; N1, N2: node; N3, N4: branch point.

Claims

1. An arc detection device comprising: a low-impedance circuit connected between a first node on a first wiring and a second node on a second wiring, the first wiring connecting a positive electrode of a DC power supply to a plurality of devices and branching from the positive electrode of the DC power supply to each of the plurality of devices, and the second wiring connecting a negative electrode of the DC power supply to the plurality of devices and branching from the negative electrode of the DC power supply to each of the plurality of devices, wherein an impedance of the low-impedance circuit is lower than an impedance of each of the plurality of devices; a current detection unit that detects a current flowing in the low-impedance circuit; as well as an arc determination unit that determines the occurrence of an arc in the first wiring or the second wiring based only on the current detected by the current detection unit, The first wiring has a plurality of first branched paths connecting a branch point in the first wiring that branches from the positive electrode of the DC power supply to each of the plurality of devices to each of the plurality of devices. The second wiring has a plurality of second branched paths connecting a branch point in the second wiring that branches from the negative electrode of the DC power supply to each of the plurality of devices to each of the plurality of devices. The current detection unit includes a magnetic core, and one of the first branched path and the second branched path corresponding to each of the plurality of devices passes through the magnetic core. The current detection unit detects the current flowing in the one path corresponding to each of the plurality of devices based on the magnetic field generated by the magnetic core, thereby detecting the current flowing in the low-impedance circuit. The one path corresponding to each device in the plurality of devices includes at least one first branched path and at least one second branched path.

2. A power regulator comprising: The arc detection device according to claim 1; and A converter converts the output power of the DC power supply.

3. An indoor wiring system comprising: The arc detection device according to claim 1; the first wiring; the second wiring; and The multiple devices are set up indoors.

4. A circuit breaker, The arc detection device according to claim 1 is provided, in, When it is determined that an arc has occurred, the circuit breaker interrupts the current flowing through the first wiring and the second wiring.

5. A solar panel, The arc detection device according to claim 1 is provided, in, The solar panels utilize solar energy to generate electricity.

6. A solar panel accessory module, The arc detection device according to claim 1 is provided, in, The solar panel auxiliary module converts the signal output from the solar panel.

7. A connection box, The arc detection device according to claim 1 is provided, in, The connection box connects the solar panel to the power conditioner.

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