WO2019208027A1 - Arc detecting circuit, breaker, power conditioner, solar panel, module with solar panel, and connection box - Google Patents

Abstract

An arc detecting circuit (10) for detecting an arc generated in a transmission path (L1) is provided with: a capacitor (C1) which is disposed in a pathway (L2) that branches from the transmission path (L1) and which causes an alternating current component signal contained in a signal flowing through the transmission path (L1) to flow from the transmission path (L1) to the pathway (L2); a resistor (R1) which is connected in series with the capacitor (C1) in the pathway (L2), and which generates a voltage signal corresponding to the alternating current component signal; a filter unit (12) into which the voltage signal generated by the resistor (R1) is input, and which allows a signal having a frequency corresponding to an arc to pass; and an arc determining unit (11) which determines the generation of an arc on the basis of the signal that has passed through the filter unit (12).

Description

Arc detection circuit, breaker, power conditioner, solar panel, solar panel module and junction box

The present invention relates to an arc detection circuit for detecting an arc in a transmission line.

2. Description of the Related Art Conventionally, a system that converts DC power supplied via a transmission line from a power supply device such as a PV (Photo Voltaic) panel (solar panel) into AC power using a power conditioner (power conditioner) is known. It has been reported that a transmission line connecting a PV panel and a power conditioner causes damage and breakage due to external factors and aging deterioration. An arc (that is, arc discharge) may occur due to such damage to the transmission path. Therefore, arc detection means for detecting an arc has been proposed (for example, Patent Document 1). The arc detection means disclosed in Patent Document 1 tries to detect an arc based on the voltage and current applied to the transmission line.

JP 2011-7765 A

By the way, the signal flowing through the transmission line when an arc is generated includes not only an arc that is an AC component but also a DC component from the power supply device. The DC component becomes an unnecessary component when detecting the arc (AC component), and the arc may not be accurately detected due to the influence of the DC component.

Therefore, an object of the present invention is to provide an arc detection circuit or the like that can accurately detect an arc generated in a transmission line.

In order to achieve the above object, one aspect of an arc detection circuit according to the present invention is an arc detection circuit that detects an arc generated in a transmission line, and is arranged in a path branched from the transmission line. A capacitor for flowing an AC component signal included in a signal flowing through the transmission path from the transmission path, a resistor connected in series with the capacitor in the path, and generating a voltage signal corresponding to the AC component signal; The voltage signal generated in the resistor is input, and a filter unit that allows a signal having a frequency corresponding to the arc to pass therethrough, and an arc determination unit that determines the occurrence of the arc based on the signal that has passed through the filter unit.

In order to achieve the above object, one aspect of the breaker according to the present invention includes the arc detection circuit described above.

In order to achieve the above object, an aspect of the power conditioner according to the present invention includes the arc detection circuit.

In order to achieve the above object, one aspect of the solar panel according to the present invention includes the arc detection circuit described above.

Further, in order to achieve the above object, one aspect of the solar panel attached module according to the present invention includes the arc detection circuit described above, and converts a signal output from the solar panel.

Further, in order to achieve the above object, one aspect of the connection box according to the present invention includes the arc detection circuit described above, and connects the solar panel and the power conditioner.

According to one aspect of the present invention, it is possible to accurately detect an arc generated in a transmission line.

FIG. 1 is a configuration diagram illustrating an example of a system to which an arc detection circuit according to Embodiment 1 is applied. FIG. 2 is a configuration diagram illustrating another example of a system to which the arc detection circuit according to the first embodiment is applied. FIG. 3 is a configuration diagram illustrating an example of a system to which an arc detection circuit according to a comparative example is applied. FIG. 4 is a configuration diagram illustrating an example of a system to which the arc detection circuit according to the second embodiment is applied. FIG. 5 is a diagram for explaining an application example of the arc detection circuit according to each embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each of the embodiments described below shows a specific example of the present invention. Therefore, numerical values, shapes, materials, components, arrangement positions of components, connection forms, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims showing the highest concept of the present invention are described as optional constituent elements.

Each figure is a schematic diagram and is not necessarily shown strictly. Moreover, in each figure, the same code | symbol is attached | subjected to the substantially same structure, The overlapping description is abbreviate | omitted or simplified.

(Embodiment 1)
The arc detection circuit according to the first embodiment will be described with reference to the drawings.

FIG. 1 is a configuration diagram illustrating an example of a system to which the arc detection circuit 10 according to the first embodiment is applied.

The arc detection circuit 10 is a circuit that detects an arc generated in the power transmission line L1 from the power supply device to the power converter. The arc detection circuit 10 includes a capacitor C1, a resistor R1, an arc determination unit 11, and a filter unit 12.

As shown in FIG. 1, a power converter 50 is connected to the transmission line L1. In the present embodiment, the power converter 50 is a part of the configuration of a power conditioner (power conditioner), for example. The power converter 50 converts DC power supplied from the solar panel 31 via the transmission line L1 into AC power. The power converter 50 employs, for example, an MPPT (Maximum Power Point Tracking) method, and adjusts the current and voltage of the DC power supplied from the solar panel 31 to values that maximize the power. For example, the power converter 50 converts it into AC power having a voltage of 100 V and a frequency of 50 Hz or 60 Hz. The AC power is used in household electrical equipment and the like.

The transmission line L1 has been reported to cause damage and breakage due to external factors and aging. An arc (that is, arc discharge) may occur due to such damage to the transmission line L1.

The capacitor C1 is a capacitor that is arranged on the path L2 branched from the transmission line L1, and that allows an AC component signal included in the signal flowing through the transmission line L1 to flow from the transmission line L1 to the path L2. Since the capacitor C1 has a function of cutting off the direct current component, only the alternating current component can be extracted from the signal flowing through the transmission line L1 and can be passed through the path L2. The capacitance value of the capacitor C1 is appropriately determined according to the frequency of the AC component to be extracted. In addition, when the capacitor provided in the power converter 50 is arranged in a path branched from the transmission line L1 in the previous stage of the conversion circuit (inverter or the like) to the AC power included in the power converter 50, A capacitor may be used as the capacitor C1.

The resistor R1 is a resistance element having a minute resistance value that is connected in series with the capacitor C1 in the path L2 and generates a voltage signal corresponding to the AC component signal. The voltage signal is a signal indicating a potential difference generated in the resistor R1 when an AC component signal (current) flows through the resistor R1. Since the potential difference has a value corresponding to the current flowing through the path L2, the resistor R1 functions as a current sensor. When a sensor such as an integrated circuit (IC) is used as the current sensor, the arc detection circuit 10 is increased in size and cost. For example, when a Hall element or the like is used as a current sensor, the Hall element itself is often larger than the resistance R1, and a separate magnetic core is also required, so that the arc detection circuit 10 is increased in size. Costs are also incurred. On the other hand, by using the resistor R1, it is possible to reduce the size and the cost.

For example, a circuit in which the capacitor C1 and the resistor R1 in the path L2 are connected in series is connected in parallel with the power converter 50. Specifically, one end of the path L2 is connected to the transmission path L1 through which current flows from the solar panel 31 to the power converter 50, and the other end of the path L2 is current from the power converter 50 to the solar panel 31. By connecting to the returning transmission line L3, the capacitor C1 and the resistor R1 connected in series in the path L2 are connected in parallel with the power converter 50. For example, the capacitor C1 is disposed on the transmission line L1 side, and the resistor R1 is disposed on the transmission line L3 side. The capacitor C1 may be disposed on the transmission line L3 side, and the resistor R1 may be disposed on the transmission line L1 side.

The filter unit 12 has a filter that receives a voltage signal generated in the resistor R1 and passes a signal having a frequency corresponding to the arc. Since the arc is generated at a specific wideband frequency, the filter blocks signals other than the frequency used for the arc determination. The filter is, for example, an RLC filter, but is not particularly limited. The pass band of the filter is appropriately determined according to the frequency of the arc that can be generated and the frequency of noise other than the arc.

The arc determination unit 11 determines the occurrence of an arc based on the signal that has passed through the filter unit 12. The arc determination unit 11 is realized by, for example, a microcomputer (microcontroller) having an AD conversion function, and acquires, for example, a voltage generated in the resistor R1 through the filter unit 12. The microcomputer is a ROM, RAM, a processor (CPU: Central Processing Unit) that executes the program, a timer, an A / D converter, a D / A converter, or the like. Note that the filter unit 12 may include an amplifier circuit. Thereby, the magnitude of the voltage generated in the resistor R1 can be amplified to a magnitude corresponding to the AD conversion function of the arc determination unit 11, and the arc determination unit 11 can correctly AD-convert the voltage.

For example, when the arc detection circuit determines the occurrence of an arc directly from the signal flowing through the transmission line L1, it is necessary to detect the arc from the signal including a DC component unnecessary for arc detection, and the arc is accurately detected by the DC component. It may not be detected. In addition, since the DC component flows through the resistor R1, it is necessary to prepare a high voltage resistance as the resistor R1.

On the other hand, in the present embodiment, the capacitor C1 (arc detection circuit 10) is arranged in the path L2 branched from the transmission line L1, so that the capacitor C1 (arc detection circuit) is normally operated when no arc is generated. The direct-current power can be supplied from the power supply device such as the solar panel 31 to the power converter 50 without being affected by 10). And when an arc generate | occur | produces, only the arc (alternating current component) can be extracted with the capacitor | condenser C1, and it can flow through the path | route L2. That is, when an arc is generated in the transmission line L1, the generation of the arc can be detected without being affected by the direct current component, so that the arc can be detected accurately. Further, since the direct current component does not flow to the resistor R1, a low breakdown voltage resistor (that is, a small resistor) can be used as the resistor R1, and the arc detection circuit 10 can be downsized.

Note that the circuit in which the capacitor C1 and the resistor R1 in the path L2 are connected in series is connected in parallel with the power converter 50, but is not limited thereto. For example, a circuit in which a capacitor C1 and a resistor R1 are connected in series may be connected as shown in FIG.

FIG. 2 is a configuration diagram illustrating another example of a system to which the arc detection circuit 10 according to the first embodiment is applied.

As shown in FIG. 2, the circuit in which the capacitor C1 and the resistor R1 in the path L2 are connected in series is connected to the ground. That is, the path L2 is not connected to the transmission path L3. The ground is a ground that is electrically insulated from the ground to which the power converter 50 is connected. For example, the capacitor C1 is disposed on the transmission line L1 side, and the resistor R1 is disposed on the ground side. Note that the capacitor C1 may be disposed on the ground side, and the resistor R1 may be disposed on the transmission line L1 side. When the resistor R1 is disposed on the transmission line L1 side, a resistor R1 having sufficient withstand voltage characteristics with respect to a voltage applied via the transmission line L1 may be selected. This is because if the withstand voltage characteristic of the resistor R1 is low, the resistor R1 may be destroyed, and accordingly, the electronic components in the arc detection circuit 10 may be destroyed.

The power converter 50 generates noise when converting direct current power into alternating current power, or generates an arc component as noise when a signal indicating the occurrence of an arc is input. In the system shown in FIG. 1, since the path L2 is connected to the transmission line L3, a noise component from the power converter 50 is transmitted to the resistor R1, and a voltage corresponding to the noise component may be generated in the resistor R1. was there. That is, there is a possibility that the influence of the noise component may be affected when the arc determination unit 11 that determines the occurrence of an arc from the voltage generated in the resistor R1 determines the occurrence of the arc.

In contrast, the ground to which the circuit in which the capacitor C1 and the resistor R1 are connected in series is connected is a ground that is electrically insulated from the ground to which the power converter 50 is connected. The converter 50 is electrically insulated. Therefore, since the noise component is difficult to be transmitted to the resistor R1, an arc generated in the transmission line L1 can be detected more accurately.

As described above, the arc detection circuit 10 according to the present embodiment is an arc detection circuit that detects an arc generated in the transmission line L1. The arc detection circuit 10 is disposed in a path L2 branched from the transmission line L1, and includes a capacitor C1 that flows an AC component signal included in a signal flowing through the transmission line L1 from the transmission line L1 to the path L2, and a capacitor C1 in the path L2. And a resistor R1 for generating a voltage signal corresponding to the AC component signal. The arc detection circuit 10 receives the voltage signal generated in the resistor R1, and determines the occurrence of an arc based on the filter unit 12 that passes a signal having a frequency corresponding to the arc and the signal that has passed through the filter unit 12. And an arc determination unit 11 for performing.

According to this, DC power can be supplied from the transmission line L1 without being affected by the capacitor C1 at normal times when no arc is generated. And when an arc generate | occur | produces, only the arc (alternating current component) can be extracted from the transmission line L1 with the capacitor | condenser C1, and it can flow to the path | route L2. That is, the arc determination unit 11 can detect the occurrence of an arc without being affected by the DC component, and can accurately detect the arc generated in the transmission line L1. In addition, since the resistor R1 that is smaller than an IC or the like is used as a current sensor for arc detection, the arc detection circuit 10 can be reduced in size. Further, since a direct current component does not easily flow through the resistor R1 connected in series with the capacitor C1, a low breakdown voltage resistor can be used as the resistor R1, and the arc detection circuit 10 can be further downsized.

The transmission line L1 is connected to a power converter that converts DC power to AC power. A circuit in which the capacitor C1 and the resistor R1 in the path L2 are connected in series is the ground to which the power converter is connected. It may be connected to an electrically isolated ground.

According to this, since the ground to which the circuit in which the capacitor C1 and the resistor R1 are connected in series is connected is a ground electrically insulated from the ground to which the power converter 50 is connected, the resistor R1 and the power The converter 50 is electrically insulated. Therefore, since the noise component generated in the power converter 50 is difficult to be transmitted to the resistor R1, the arc generated in the transmission line L1 can be detected more accurately.

The transmission line L1 is connected to a power converter that converts DC power into AC power, and the circuit in which the capacitor C1 and the resistor R1 in the path L2 are connected in series may be connected in parallel with the power converter. Good.

Thus, the resistor R1 does not need to be electrically insulated from the power converter 50, and the design effort for electrical insulation can be saved.

Note that another current sensor may be arranged instead of the resistor R1.

FIG. 3 is a configuration diagram illustrating an example of a system to which the arc detection circuit 100 according to the comparative example is applied.

In the comparative example shown in FIG. 3, the current sensor 13 is arranged instead of the resistor R1. The current sensor 13 is a current sensor that is connected in series with the capacitor C1 in the path L2 and generates a voltage signal corresponding to the AC component signal. The current sensor 13 is, for example, a sensor using a Hall element and a magnetic core. For example, by arranging the magnetic core so that the path L2 penetrates the magnetic core, a magnetic field corresponding to the current flowing through the path L2 is generated in the magnetic core. When the Hall element is placed in the magnetic field, a voltage corresponding to the magnetic field (that is, a current flowing through the path L2) is generated. At this time, since the DC component is less likely to flow through the path L2 passing through the magnetic core due to the capacitor C1, magnetic saturation is unlikely to occur in the magnetic core due to the DC component, and the dynamic range of the current sensor 13 can be expanded. Thus, for example, the current can be accurately detected by using the current sensor 13 such as a Hall element.

The ground to which the circuit in which the capacitor C1 and the current sensor 13 are connected in series is connected is a ground that is electrically insulated from the ground to which the power converter 50 is connected. Thereby, the current sensor 13 and the power converter 50 are electrically insulated. Therefore, since the noise component generated in the power converter 50 becomes difficult to be transmitted to the current sensor 13, the arc generated in the transmission line L1 can be detected more accurately.

(Embodiment 2)
Next, an arc detection circuit according to the second embodiment will be described with reference to FIG.

FIG. 4 is a configuration diagram illustrating an example of a system to which the arc detection circuit 10a according to the second embodiment is applied.

The arc detection circuit 10a is further different from the arc detection circuit 10 according to the first embodiment in that a diode D1 is provided. Since other points are the same as those in the first embodiment, description thereof is omitted.

The arc detection circuit 10a includes a diode D1 connected in series with the capacitor C1 and the resistor R1 in the path L2. In the second embodiment, the circuit in which the capacitor C1, the resistor R1, and the diode D1 are connected in series is connected to the power converter 50 in parallel. That is, the system configuration in the second embodiment is a configuration in which the diode D1 is further added to the system described in FIG.

In the path L2, these are arranged in the order of the capacitor C1, the resistor R1, and the diode D1 from the transmission line L1 side to the transmission line L3 side. That is, the anode of the diode D1 is connected to the transmission line L1 side, and the cathode is connected to the transmission line L3 side. Specifically, the anode of the diode D1 is connected to the resistor R1, and the cathode is connected to the transmission line L3. The order in which the capacitor C1, the resistor R1, and the diode D1 are arranged is not limited to the order shown in FIG. 4 and may be arranged in any order. When the diode D1 is connected to the transmission line L1, the voltage and current applied and input through the transmission line L1 may not be able to endure depending on the performance of the diode D1. Further, depending on the direction of the diode D1, a reverse current may be generated and damaged. For this reason, the capacitor C1, the resistor R1, and the diode D1 are preferably arranged as shown in FIG.

As described above, the power converter 50 generates noise when converting direct current power into alternating current power, or generates an arc component as noise when a signal in which an arc is generated is input. . In one example in the first embodiment, the resistor R1 and the power converter 50 are electrically insulated by dropping the path L2 to the ground electrically insulated from the ground to which the power converter 50 is connected. The resistor R1 is not affected by the noise component. In the second embodiment, by providing the diode D1, it is difficult for the noise component of the power converter 50 to enter the path L2 by the diode D1, and the resistor R1 can be prevented from being affected by the noise component. Therefore, it is possible to detect the arc generated in the transmission line L1 more accurately.

Note that the circuit in which the capacitor C1, the resistor R1, and the diode D1 are connected in series may be connected to a ground that is electrically insulated from the ground to which the power converter 50 is connected. That is, the system configuration in the second embodiment may be a configuration in which the diode D1 is further added to the system described in FIG. In this case, a noise component from the ground is less likely to enter the path L2 by the diode D1, and the resistor R1 can be prevented from being affected by the noise component.

(Embodiment 3)
In the third embodiment, an application example of the arc detection circuits 10 and 10a will be described.

FIG. 5 is a diagram for explaining an application example of the arc detection circuits 10 and 10a according to each embodiment.

As described above, for example, the arc detection circuits 10 and 10 a exchange DC power supplied from the solar panel 31 via the transmission line L <b> 1 with the power conditioner (power conditioner) 51 configured by the power converter 50. Applies to systems that convert power. In this application example, three solar panels 31 connected in series by one string 60 are arranged to form the solar cell array 30. The strings 60 are collected by the connection box 40 and connected to the power conditioner 51.

For example, a breaker 41 is provided for each string 60, and here, the breaker 41 is provided in the connection box 40. Note that the breaker 41 may not be provided in the connection box 40. For example, the breaker 41 may be provided between the connection box 40 and the solar cell array 30, or may be provided between the connection box 40 and the power conditioner 51 without being provided for each string 60.

The solar panel 31 includes, for example, a solar panel attached module 32 that converts a signal output from the solar panel 31. Note that the solar panel 31 may not have the solar panel accessory module 32. The solar panel attachment module 32 is, for example, a DC / DC converter that optimizes the power generation amount for each solar panel 31.

For example, the breaker 41 may include the arc detection circuits 10 and 10a. In this case, the transmission line L1 becomes a transmission line (for example, the string 60) connected to the breaker 41, and the current flowing through the string 60 where the arc is generated can be cut off. For example, when the arc determination unit 11 determines that an arc has occurred, the breaker 41 interrupts the current flowing through the string 60 in which the arc has occurred. The string 60 in which no arc is generated can be used without interrupting the current.

For example, the power conditioner 51 may include the arc detection circuits 10 and 10a. In this case, a circuit in which the capacitor C1 and the resistor R1 in the path L2 in the power converter 51 are connected in series is connected to a ground electrically isolated from the ground to which the power converter 50 is connected, or an arc detection circuit. 10 and the power converter 50 are connected in parallel, or the circuit connected in series is connected in parallel with the power converter 50. Further, the transmission line L1 is a transmission line connected to the power conditioner 51, and can stop the power conditioner 51 in response to the occurrence of an arc. For example, when the arc determination unit 11 determines that an arc has occurred, the power conditioner 51 stops.

Further, for example, the solar panel 31 or the solar panel attached module 32 may include the arc detection circuits 10 and 10a. In this case, the transmission line L1 becomes a transmission line (for example, the string 60) connected to the solar panel 31, and the output to the string 60 where the arc is generated can be stopped. For example, when the arc determination unit 11 determines that an arc has occurred, the solar panel 31 or the solar panel attachment module 32 stops output to the string 60 in which the arc has occurred. The string 60 in which no arc is generated can be used without stopping the output.

For example, the junction box 40 may include the arc detection circuits 10 and 10a. In this case, the transmission line L1 becomes a transmission line (for example, the string 60) connected to the connection box 40, and the current flowing through the string 60 where the arc is generated can be interrupted via, for example, the breaker 41 or the like. For example, when the arc determination unit 11 determines that an arc has occurred, the junction box 40 interrupts the current flowing through the string 60 in which the arc has occurred. The string 60 in which no arc is generated can be used without interrupting the current.

The arc detection circuits 10 and 10a are not limited to the above system, and can be applied to any system that needs to detect the occurrence of an arc. Moreover, the breaker 41, the power conditioner 51, the solar panel 31, the solar panel attachment module 32, or the connection box 40 may include the arc detection circuit 100 according to the comparative example.

As described above, the breaker 41 may include the arc detection circuits 10 and 10a. Further, the power conditioner 51 may include arc detection circuits 10 and 10a. Moreover, the solar panel 31 may include the arc detection circuits 10 and 10a. Moreover, the solar panel attachment module 32 may include the arc detection circuits 10 and 10a, and may convert a signal output from the solar panel. Moreover, the connection box 40 may include the arc detection circuits 10 and 10 a and connect the solar panel 31 and the power conditioner 51.

(Other embodiments)
The arc detection circuit 10 and the like according to the embodiment have been described above, but the present invention is not limited to the above embodiment.

Although the arc detection circuits 10 and 10a according to the above-described embodiment are realized as software by a microcomputer, they may be realized as software in a general-purpose computer such as a personal computer. Furthermore, the arc detection circuit 10 may be realized in hardware by a dedicated electronic circuit including an A / D converter, a logic circuit, a gate array, a D / A converter, and the like.

In addition, it is realized by arbitrarily combining the components and functions in each embodiment without departing from the scope of the present invention, or a form obtained by subjecting each embodiment to various modifications conceived by those skilled in the art. Forms are also included in the present invention.

DESCRIPTION OF SYMBOLS 10, 10a, 100 Arc detection circuit 11 Arc determination part 12 Filter part 31 Solar panel 32 Solar panel attachment module 40 Connection box 41 Breaker 50 Power converter 51 Power conditioner (power conditioner)
C1 Capacitor L1, L3 Transmission path L2 Path R1 Resistance

Claims (9)

1. An arc detection circuit for detecting an arc generated in a transmission line,
   A capacitor that is arranged in a path branched from the transmission path, and that allows a signal of an alternating current component included in a signal flowing in the transmission path to flow from the transmission path to the path;
   A resistor connected in series with the capacitor in the path to generate a voltage signal corresponding to the signal of the AC component;
   The voltage signal generated in the resistor is input, a filter unit that passes a signal having a frequency corresponding to the arc, and
   An arc determination unit that determines the occurrence of an arc based on a signal that has passed through the filter unit;
   Arc detection circuit.
2. A power converter that converts DC power to AC power is connected to the transmission line,
   The circuit in which the capacitor and the resistor in the path are connected in series is connected to a ground that is electrically insulated from the ground to which the power converter is connected.
   The arc detection circuit according to claim 1.
3. A power converter that converts DC power to AC power is connected to the transmission line,
   A circuit in which the capacitor and the resistor in the path are connected in series is connected in parallel with the power converter,
   The arc detection circuit according to claim 1.
4. The arc detection circuit further includes a diode in series with the capacitor and the resistor in the path.
   The arc detection circuit according to any one of claims 1 to 3.
5. The arc detection circuit according to any one of claims 1 to 4,
   breaker.
6. The arc detection circuit according to any one of claims 1 to 4,
   Inverter.
7. The arc detection circuit according to any one of claims 1 to 4,
   Solar panel.
8. The arc detection circuit according to any one of claims 1 to 4,
   Convert the signal output from the solar panel,
   Module with solar panel.
9. The arc detection circuit according to any one of claims 1 to 4,
   Connect the solar panel and the inverter.
   Connection box.

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