Arc discharge detection circuit and power supply system

Abstract

The utility model discloses an arc discharge detection circuit and a power supply system, in the scheme, an arc discharge detection module is connected between a photovoltaic assembly and a tripping switch, and the output current of the photovoltaic assembly can be collected no matter whether arc discharge occurs between the positive end and the negative end of the tripping switch or not; particularly, when arc discharge occurs between the positive end and the negative end of the tripping switch, short circuit occurs between the positive end and the negative end of the tripping switch, namely, a voltage conversion module bypass at the rear end and a load connected with the photovoltaic module become smaller, so that the output current becomes larger, and the control circuit detects that the output current of the photovoltaic module is larger than a preset current threshold value through the tripping switch; if yes, the voltage conversion module can be immediately controlled to stop working, so that the photovoltaic module stops outputting, and the voltage conversion module and the photovoltaic module are protected.

Description

TECHNICAL FIELD

[0001] The utility model relates to new energy power supply field especially relates to a pull arc detection circuit and power supply system. BACKGROUND

[0002] The photovoltaic module converts solar energy into electric energy and outputs direct current, but due to the instability of light intensity, the direct current output by the photovoltaic module is not stable, if the direct current output by the photovoltaic module is used to supply power to the load, the output positive terminal and the output negative terminal of the photovoltaic module need to be connected with the voltage conversion module, so that the voltage conversion module converts the direct current output by the photovoltaic module into stable direct current to supply power to the load.

[0003] However, if the circuit connection between the photovoltaic module and the voltage conversion module is abnormal, there will be pull arc between the output terminal of the photovoltaic module and the voltage conversion module, which will cause damage to the photovoltaic module and / or the voltage conversion module. In addition, when the output positive terminal of the photovoltaic module and the input positive terminal of the voltage conversion module, and the output negative terminal of the photovoltaic module and the input negative terminal of the voltage conversion module are provided with a trip switch, if the trip switch is abnormally disconnected, pull arc may also occur between the positive terminal and the negative terminal of the trip switch. Therefore, how to detect the pull arc occurring in the circuit is a problem that needs to be solved by those skilled in the art. UTILITY MODEL CONTENTS

[0004] The utility model aims at providing a pull arc detection circuit and power supply system, in the scheme, the pull arc detection module is connected between the photovoltaic module and the trip switch, no matter whether pull arc occurs between the positive terminal and the negative terminal of the trip switch, the output current of the photovoltaic module can be collected, especially when pull arc occurs between the positive terminal and the negative terminal of the trip switch, the positive terminal and the negative terminal of the trip switch are short-circuited, that is, the voltage conversion module at the back end is bypassed, the load connected with the photovoltaic module becomes smaller, therefore, the output current becomes larger, the control circuit detects that the output current of the photovoltaic module is greater than the preset current threshold value through the trip switch, then the voltage conversion module can be immediately controlled to stop working, and the photovoltaic module is stopped from outputting, so as to realize the protection of the voltage conversion module and the photovoltaic module.

[0005] To solve the above technical problems, the utility model provides a pull arc detection circuit, comprising:

[0006] The first positive terminal is connected with the output positive terminal of the photovoltaic module, the second positive terminal is connected with the first positive terminal of the trip switch, and the pull arc detection module is used for collecting the output current of the photovoltaic module;

[0007] The output negative terminal of the photovoltaic module is connected with the first negative terminal of the trip switch, the second positive terminal of the trip switch is connected with the input positive terminal of the voltage conversion module, and the second negative terminal of the trip switch is connected with the input negative terminal of the voltage conversion module.

[0008] The input end is connected with the output end of the arc detection module, and the output end is connected with the control end of the voltage conversion module, and the control circuit is used for controlling the voltage conversion module to stop working when the output current of the photovoltaic module is greater than a preset current threshold.

[0009] Preferably, the arc detection module comprises a current transformer;

[0010] The first end of the primary coil of the current transformer is connected with the output positive end of the photovoltaic module, and the second end of the primary coil is connected with the first positive end of the trip switch, so as to induce the output current of the photovoltaic module when the output current of the photovoltaic module changes;

[0011] The first end of the secondary coil of the current transformer and the first end of the control circuit are connected, and the second end of the secondary coil is connected with the second end of the control circuit, so as to transmit the output current of the photovoltaic module induced by the primary coil to the control circuit.

[0012] Preferably, the control circuit comprises a current comparison module and a control module;

[0013] The input end of the current comparison module is connected with the secondary coil of the current transformer, so as to judge whether the output current of the photovoltaic module is greater than a preset current threshold based on the current on the secondary coil of the current transformer, and output a preset high level when the output current of the photovoltaic module is greater than the preset current threshold;

[0014] The input end of the control module is connected with the output end of the current comparison module, and the output end of the control module is connected with the control end of the voltage conversion module, so as to control the voltage conversion module to stop working when the preset high level is received.

[0015] Preferably, the current comparison module comprises a sampling resistor, an amplifier and a comparator;

[0016] The first end of the sampling resistor is connected with the first end of the secondary coil of the current transformer, and the second end is connected with the second end of the secondary coil of the current transformer, so as to convert the current on the secondary coil of the current transformer into a sampling voltage;

[0017] The first input end of the amplifier is connected with the first end of the sampling resistor, and the second input end is connected with the second input end of the sampling resistor, so as to amplify the sampling voltage based on a preset gain;

[0018] The first input end of the comparator is connected with the output end of the amplifier, the second input end is connected with a preset voltage threshold, and the output end is connected with the input end of the control module, so as to output the preset high level when the sampling voltage after the amplification processing is greater than the preset voltage threshold; the preset voltage threshold is a voltage value determined based on the preset current threshold and the preset gain.

[0019] Preferably, the turns ratio of the primary coil to the secondary coil of the current transformer is greater than 1.

[0020] The preset voltage threshold is a voltage value determined based on the preset current threshold, the preset gain, and the turns ratio of the current transformer.

[0021] Preferably, the turns ratio of the primary coil to the secondary coil of the current transformer is greater than 1.

[0022] The alarm circuit connected with the alarm signal output end of the control circuit is used to perform arc drawing alarm when the arc drawing alarm signal is received.

[0023] The control circuit is further used to output the arc drawing alarm signal when the output current of the photovoltaic module is greater than the preset current threshold.

[0024] Preferably, the alarm circuit includes a sound alarm circuit and / or a light alarm circuit.

[0025] The sound alarm circuit is used to perform sound arc drawing alarm when the arc drawing alarm signal is received.

[0026] The light alarm circuit is used to perform light arc drawing alarm when the arc drawing alarm signal is received.

[0027] Preferably, the sound alarm circuit includes a buzzer and / or a loudspeaker.

[0028] The light alarm circuit includes an LED lamp and / or a display screen.

[0029] Preferably, the first positive end of the arc drawing detection module is connected with the output positive end of the N photovoltaic modules, and the second positive end is connected with the first positive end of the trip switch; N is a positive integer.

[0030] The output negative ends of the N photovoltaic modules are connected with each other and connected with the first negative end of the trip switch.

[0031] To solve the above technical problems, the application further provides a power supply system including the arc drawing detection circuit as described above, and further including:

[0032] The output positive end of the photovoltaic module is connected with the first positive end of the arc drawing detection circuit, and the output negative end is connected with the first negative end of the trip switch, so as to convert solar energy into electric energy and output direct current.

[0033] The first positive end is connected with the second positive end of the arc detection circuit, the second positive end is connected with the input positive end of the voltage conversion module, the second negative end is connected with the input negative end of the voltage conversion module of the trip switch, and the trip switch is used for turning off when the current between the first positive end and the second positive end of the trip switch and the current between the first negative end and the second negative end of the trip switch are greater than a preset protection current threshold value;

[0034] The control end is connected with the output end of the arc detection circuit, and the voltage conversion module connected with the load is used for converting the direct current output by the photovoltaic module and supplying power to the load.

[0035] The arc detection module is connected between the photovoltaic module and the trip switch, and the output current of the photovoltaic module can be collected whether the arc appears between the positive end and the negative end of the trip switch or not. In particular, when the arc appears between the positive end and the negative end of the trip switch, the positive end and the negative end of the trip switch are short-circuited, that is, the voltage conversion module at the rear end is bypassed, the load connected with the photovoltaic module becomes smaller, and thus the output current of the photovoltaic module becomes larger. The control circuit detects that the output current of the photovoltaic module is greater than a preset current threshold value through the trip switch, and then the voltage conversion module can be immediately controlled to stop working, and the photovoltaic module is stopped from outputting, so as to realize the protection of the voltage conversion module and the photovoltaic module. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0037] Figure 1 The structure diagram of the arc detection circuit provided by the present application is shown in the figure.

[0038] Figure 2 The structure diagram of the arc detection circuit in the prior art is shown in the figure.

[0039] Figure 3 The structure diagram of the arc detection module provided by the present application is shown in the figure.

[0040] Figure 4 The flowchart of current comparison of the current comparison module provided by the present application is shown in the figure.

[0041] Figure 5 The structure diagram of the arc detection circuit connected with multiple photovoltaic modules provided by the present application is shown in the figure. DETAILED DESCRIPTION

[0042] The core of the utility model discloses a kind of arc detection circuit and power supply system, in the scheme, arc detection module is connected between photovoltaic module and trip switch, whether arc appears between the positive terminal and the negative terminal of trip switch, the output current of photovoltaic module can be collected, especially when arc appears between the positive terminal and the negative terminal of trip switch, short circuit between the positive terminal and the negative terminal of trip switch, i.e. rear-end voltage conversion module bypass, load connected by photovoltaic module becomes small, therefore, its output current becomes large, control circuit detects that the output current of photovoltaic module is greater than preset current threshold by trip switch, then voltage conversion module can be immediately controlled to stop working, to make photovoltaic module stop output, to realize the protection of voltage conversion module and photovoltaic module.

[0043] To make the purpose, technical scheme and advantage of the utility model embodiment clearer, the technical scheme in the utility model embodiment will be clearly and completely described in the following with reference to the drawings in the utility model embodiment, obviously, the described embodiment is a part of the embodiment of the utility model, not all embodiments. Based on the embodiment in the utility model, all other embodiments obtained by the person skilled in the art without making creative labor belong to the scope of the utility model protection.

[0044] Please refer to Figure 1 , Figure 1 The structure schematic diagram of a kind of arc detection circuit provided for this application, the circuit includes:

[0045] The first positive terminal is connected with the output positive terminal of photovoltaic module, the second positive terminal is connected with the first positive terminal of trip switch, and arc detection module 1 is used to collect the output current of photovoltaic module;

[0046] The output negative terminal of photovoltaic module is connected with the first negative terminal of trip switch, the second positive terminal of trip switch is connected with the input positive terminal of voltage conversion module, and the second negative terminal of trip switch is connected with the input negative terminal of voltage conversion module;

[0047] The output terminal of arc detection module 1 is connected with the input terminal, and the output terminal of control circuit 2 is connected with the control terminal of voltage conversion module, for controlling voltage conversion module to stop working when the output current of photovoltaic module is greater than preset current threshold.

[0048] After photovoltaic (PV) modules convert solar energy into electrical energy and output direct current (DC), a voltage conversion module converts the DC voltage to power the load. To facilitate disconnection of the circuit between the PV modules and the voltage conversion module for maintenance, a switching circuit is typically installed between them. The most common existing technology uses a DC switch, which is manually controlled by personnel, thus preventing abnormally frequent switching on and off. Since PV modules are usually installed outdoors, they inevitably get wet from rain or dew, especially in the morning and evening when dew accumulates. This can cause short circuits at the output terminals of the PV modules, potentially leading to arcing in the circuit connecting the PV modules and the voltage conversion module. This can result in excessive output current from the PV modules. When the arcing detection module 1, located between the DC switch and the voltage conversion module, detects this increased output current, the control circuit 2 can stop the voltage conversion module from operating, protecting both the module and the PV modules.

[0049] However, for circuit protection, trip switches are now commonly used instead of DC switches. Please refer to [link / reference]. Figure 2 , Figure 2 This is a schematic diagram of an existing arc detection circuit. When a large current occurs in the circuit, the trip switch can immediately shut off, disconnecting the circuit between the photovoltaic module and the voltage conversion module. After the fault is cleared, the trip switch is manually closed. However, because the trip switch has a limited lifespan—that is, when the number of times the trip switch is turned on and off exceeds the maximum number—arcging occurs between the positive and negative terminals of the trip switch, causing a short circuit between them through the air medium. Figure 2 The arcing point shown bypasses the voltage conversion module. If the arcing detection module 1 is still located between the trip switch and the voltage conversion module, then the arcing detection module 1 will also be short-circuited and unable to detect the output current of the photovoltaic module. If arcing continues between the positive and negative terminals of the trip switch and cannot be detected, it will cause the photovoltaic module to malfunction, and may even lead to a fire.

[0050] Based on this, the arc detection module 1 is set between the photovoltaic module and the trip switch in this application. Whether an arc occurs at the output terminal of the photovoltaic module or between the positive and negative terminals of the trip switch, the arc detection module 1 can detect the output current of the photovoltaic module. When the control circuit 2 determines that the output current of the photovoltaic module is greater than the preset current threshold, it will shut down the voltage conversion module in time, and the photovoltaic module will stop outputting, thereby realizing arc extinguishing and protecting the various devices in the circuit.

[0051] wherein, Figure 1 PV is a photovoltaic module, S1 and S2 are trip switches.

[0052] It should be noted that the control circuit 2 can detect the output current of the photovoltaic module by CT, and perform FFT analysis, and judge the arc through the frequency and amplitude of the output current of the photovoltaic module. Once the arc is detected, the voltage conversion module is immediately controlled to stop working.

[0053] In summary, the arc detection module 1 in the present application is connected between the photovoltaic module and the trip switch. Whether an arc occurs between the positive and negative terminals of the trip switch or not, the output current of the photovoltaic module can be collected. In particular, when an arc occurs between the positive and negative terminals of the trip switch, the positive and negative terminals of the trip switch are short-circuited, that is, the voltage conversion module at the back end is bypassed, and the load connected to the photovoltaic module becomes smaller. Therefore, the output current becomes larger. The control circuit 2 detects that the output current of the photovoltaic module is greater than the preset current threshold through the trip switch, and then controls the voltage conversion module to stop working, thereby stopping the output of the photovoltaic module, so as to protect the voltage conversion module and the photovoltaic module.

[0054] On the basis of the above embodiment:

[0055] As a preferred embodiment, the arc detection module 1 includes a current transformer;

[0056] The first end of the primary coil of the current transformer is connected to the output positive terminal of the photovoltaic module, and the second end of the primary coil is connected to the first positive terminal of the trip switch, for sensing the output current of the photovoltaic module when the output current of the photovoltaic module changes;

[0057] The first end of the secondary coil of the current transformer is connected to the first end of the control circuit 2, and the second end of the secondary coil is connected to the second end of the control circuit 2, for transmitting the output current of the photovoltaic module sensed by the primary coil to the control circuit 2.

[0058] The arc detection module 1 in the present application includes a current transformer. The primary coil of the current transformer is connected in series to the circuit between the photovoltaic module and the trip switch, so as to obtain the output current of the photovoltaic module. The secondary coil of the current transformer is inducted with the primary coil, so as to transmit the current to the control circuit 2, thereby enabling the control circuit 2 to determine whether the output current of the photovoltaic module is greater than the preset current threshold based on the current on the secondary coil.

[0059] Please refer to Figure 3 , Figure 3A structure diagram of an arc detection module is provided in the present application. Among them, PV+ is the output positive terminal of the photovoltaic module, the current from PV+ passes through the primary side coil of the current transformer, enters the trip switch, and the current of the secondary side coil is transmitted to the control circuit 2.

[0060] By using the current transformer to collect the output current of the photovoltaic module, the circuit isolation between the photovoltaic module and the control circuit 2 can be realized, and the threat to personnel safety caused by the large current output of the photovoltaic module can be avoided.

[0061] As a preferred embodiment, the control circuit 2 includes a current comparison module and a control module;

[0062] The input end of the current comparison module is connected with the secondary side coil of the current transformer, and is used for judging whether the output current of the photovoltaic module is greater than a preset current threshold based on the current on the secondary side coil of the current transformer, and outputting a preset high level when the output current of the photovoltaic module is greater than the preset current threshold;

[0063] The input end of the control module is connected with the output end of the current comparison module, and the output end of the control module is connected with the control end of the voltage conversion module, and is used for controlling the voltage conversion module to stop working when the preset high level is received.

[0064] In the control circuit 2 in the embodiment, by setting the current comparison module, whether the output current of the photovoltaic module is greater than the preset current threshold can be judged based on the current on the secondary side coil of the current transformer, so that the preset high level is output when it is determined that the output current of the photovoltaic module is greater than the preset current threshold, so that the control module controls the voltage conversion module to stop working when the preset high level is received.

[0065] It can be seen that by setting the current comparison module and the control module, the current comparison work and the control work of the voltage conversion module are executed separately, so as to reduce the power consumption of the control module and improve the service life of the current comparison module and the control module.

[0066] As a preferred embodiment, the current comparison module includes a sampling resistor, an amplifier and a comparator;

[0067] The first end of the sampling resistor is connected with the first end of the secondary side coil of the current transformer, and the second end is connected with the second end of the secondary side coil of the current transformer, and is used for converting the current on the secondary side coil of the current transformer into a sampling voltage;

[0068] The first input end of the amplifier is connected with the first end of the sampling resistor, and the second input end is connected with the second input end of the sampling resistor, and is used for amplifying the sampling voltage based on a preset gain;

[0069] The first input end of the comparator is connected with the output end of the amplifier, the second input end is connected with a preset voltage threshold, and the output end is connected with the input end of the control module and used for outputting a preset high level when the sampling voltage after the amplification processing is greater than the preset voltage threshold.

[0070] The current comparison module in the embodiment includes a sampling resistor, an amplifier and a comparator. The sampling resistor converts the current on the secondary coil of the current transformer into a sampling voltage, and the amplifier amplifies the sampling voltage. Then, the comparator compares the sampling voltage after the amplification processing with a preset voltage threshold. When the sampling voltage after the amplification processing is greater than the preset voltage threshold, it can be determined that the output current of the photovoltaic module is greater than the preset voltage threshold, so that it can be determined that the arc appears in the circuit, and the control module can control the voltage conversion module to stop working. Please refer to Figure 4 , Figure 4 A flowchart for the current comparison of the current comparison module provided in the application is shown.

[0071] The preset voltage threshold is a voltage value determined based on the preset current threshold and the preset gain. Specifically, when the turns ratio of the primary coil to the secondary coil of the current transformer is 1, the current on the secondary coil of the current transformer is the same as the current on the primary coil, that is, the current on the secondary coil of the current transformer is the output current of the photovoltaic module. The sampling resistor samples the current, and the sampling voltage between the two ends of the sampling resistor is the product of the current on the secondary coil of the current transformer and the resistance of the sampling resistor. After amplification by the amplifier, the sampling voltage after the amplification processing is the product of the sampling voltage before the amplification processing and the preset gain. Based on this, the preset voltage threshold set is the critical value of the output current of the photovoltaic module from the time when the arc never appears in the circuit to the time when the arc appears, that is, the product of the preset current threshold, the resistance of the sampling resistor and the preset gain. Of course, the application does not limit this, and the sampling voltage after the amplification processing can be compared with the preset voltage threshold to determine whether the arc appears in the circuit.

[0072] As a preferred embodiment, the turns ratio of the primary coil to the secondary coil of the current transformer is greater than 1.

[0073] The preset voltage threshold is specifically a voltage value determined based on the preset current threshold, the preset gain and the turns ratio of the current transformer.

[0074] In the embodiment, when the arc appears in the circuit, the output current of the photovoltaic module is large, in order to protect the circuit, the turns ratio of the primary coil and the secondary coil of the current transformer is set to be greater than 1, so that the current on the secondary coil of the current transformer is smaller than the current on the primary coil, so as to reduce the output current of the photovoltaic module and then compare, so as to protect the control circuit 2 and avoid the device in the control circuit 2 from being burned out due to the large current. Please refer to Figure 4 .

[0075] Based on this, when the turns ratio is a and a is greater than 1, the current on the secondary coil of the current transformer is 1 / a of the current on the primary coil, and the preset voltage threshold also needs to be adjusted based on the turns ratio, that is, the preset voltage threshold is the product of the preset current threshold, the resistance of the sampling resistor, the preset gain and 1 / a.

[0076] As a preferred embodiment, it further comprises:

[0077] The alarm circuit connected with the alarm signal output end of the control circuit 2, used for alarming when the arc alarm signal is received;

[0078] The control circuit 2 is further used for outputting the arc alarm signal when the output current of the photovoltaic module is greater than the preset current threshold.

[0079] In the embodiment, after the control circuit 2 determines that the arc appears in the circuit and controls the voltage conversion module to stop working, the control circuit 2 further outputs the arc alarm signal, so that the alarm circuit alarms the arc, which facilitates the staff to timely investigate the reason why the arc appears in the circuit and to maintain, thereby improving the efficiency of the photovoltaic module in use.

[0080] As a preferred embodiment, the alarm circuit comprises a sound alarm circuit and / or a light alarm circuit;

[0081] The sound alarm circuit is used for sounding the arc alarm when the arc alarm signal is received;

[0082] The light alarm circuit is used for lighting the arc alarm when the arc alarm signal is received.

[0083] The alarm circuit in the embodiment can but is not limited to be realized by the sound alarm circuit and / or the light alarm circuit, wherein the sound alarm circuit can sound the arc alarm, so that the staff can timely know that the arc appears in the circuit when it is inconvenient to check the light alarm circuit.

[0084] The light alarm circuit can make the staff know that the arc appears in the circuit in time through the light arc alarm when the environment is relatively noisy.

[0085] Therefore, the staff can determine whether the arc appears in the circuit in time in any working state, so as to investigate the cause of the arc appearing in the circuit and maintain the circuit.

[0086] As a preferred embodiment, the sound alarm circuit comprises a buzzer and / or a loudspeaker.

[0087] The light alarm circuit comprises an LED lamp and / or a display screen.

[0088] The sound alarm circuit in the embodiment can be provided with a buzzer and / or a loudspeaker, and the sound arc alarm can be performed by setting the buzzer frequency and the loudspeaker sound size. The light alarm circuit is provided with an LED lamp and / or a display screen, and the light arc alarm can be performed by setting the color and brightness of the LED lamp and / or the display information of the display screen.

[0089] The buzzer, loudspeaker and LED lamp can not only perform the corresponding arc alarm, but also have low cost and simple setting. In addition, the display screen can not only perform the light arc alarm, but also display the working state of the photovoltaic module and the voltage conversion module, so that the staff can know the working state of the entire circuit.

[0090] As a preferred embodiment, the first positive terminal of the arc detection module 1 is connected with the output positive terminal of the N photovoltaic modules, and the second positive terminal is connected with the first positive terminal of the trip switch; N is a positive integer.

[0091] The output negative terminals of the N photovoltaic modules are connected and connected with the first negative terminal of the trip switch.

[0092] In the embodiment, the plurality of photovoltaic modules can be connected in parallel to improve the output power of the voltage conversion module and improve the load capacity of the voltage conversion module. Please refer to Figure 5 , Figure 5 A structure diagram of an arc detection circuit connected with a plurality of photovoltaic modules is provided in the application. Taking three photovoltaic modules as an example, PV1, PV2 and PV3 are photovoltaic modules, the output positive terminals of the three photovoltaic modules are connected, and the output negative terminals are connected.

[0093] In order to solve the above technical problems, the application also provides a power supply system comprising the arc detection circuit as described above, and further comprising:

[0094] The photovoltaic module with the output positive terminal connected with the first positive terminal of the arc detection circuit and the output negative terminal connected with the first negative terminal of the trip switch is used to convert solar energy into electric energy and output direct current.

[0095] The first positive end is connected with the second positive end of the arc-detecting circuit, the second positive end is connected with the input positive end of the voltage conversion module, the second negative end is connected with the input negative end of the voltage conversion module, and the trip switch is used for being turned off when the current between the first positive end and the second positive end of the trip switch and the current between the first negative end and the second negative end of the trip switch are greater than a preset protection current threshold value;

[0096] The control end is connected with the output end of the arc-detecting circuit, and the voltage conversion module is connected with the load and is used for converting the direct current output by the photovoltaic module into voltage to supply power to the load.

[0097] For the power supply system provided by the utility model, please refer to the above-mentioned embodiments of the arc-detecting circuit, and the utility model will not be described here.

[0098] It should be further understood that the terms such as first and second, and the like, are used herein to distinguish one element from another, but do not otherwise limit those elements. Moreover, the terms "including", "including", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not include only those elements recited, but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or apparatus including the element.

[0099] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the utility model. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the utility model. Therefore, the utility model will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An arc detection circuit, characterized by, The application relates to a current detection device for a photovoltaic module. The device comprises: a pull arc detection module, whose first positive terminal is connected with the output positive terminal of the photovoltaic module, and whose second positive terminal is connected with the first positive terminal of a trip switch, and which is used for collecting the output current of the photovoltaic module; the output negative terminal of the photovoltaic module is connected with the first negative terminal of the trip switch; the second positive terminal of the trip switch is connected with the input positive terminal of a voltage conversion module; the second negative terminal of the trip switch is connected with the input negative terminal of the voltage conversion module; a control circuit, whose input terminal is connected with the output terminal of the pull arc detection module, and whose output terminal is connected with the control terminal of the voltage conversion module, and which is used for controlling the voltage conversion module to stop working when the output current of the photovoltaic module is greater than a preset current threshold value. The pull arc detection module comprises a current transformer. The first end of the primary coil of the current transformer is connected with the output positive terminal of the photovoltaic module; the second end of the primary coil is connected with the first positive terminal of the trip switch, and is used for sensing the output current of the photovoltaic module when the output current of the photovoltaic module changes; the first end of the secondary coil of the current transformer is connected with the control circuit; the second end of the secondary coil is connected with the control circuit, and is used for transmitting the output current of the photovoltaic module sensed by the primary coil to the control circuit.

2. The arc detection circuit of claim 1, wherein, The control circuit comprises a current comparison module and a control module. The input terminal of the current comparison module is connected with the secondary coil of the current transformer, and is used for judging whether the output current of the photovoltaic module is greater than a preset current threshold value based on the current on the secondary coil of the current transformer, and outputting a preset high level when the output current of the photovoltaic module is greater than the preset current threshold value. The input terminal of the control module is connected with the output terminal of the current comparison module; the output terminal of the control module is connected with the control terminal of the voltage conversion module, and is used for controlling the voltage conversion module to stop working when the preset high level is received.

3. The arc draw detection circuit of claim 2, wherein, The current comparison module comprises a sampling resistor, an amplifier and a comparator. The first end of the sampling resistor is connected with the first end of the secondary coil of the current transformer; the second end of the sampling resistor is connected with the second end of the secondary coil of the current transformer, and is used for converting the current on the secondary coil of the current transformer into a sampling voltage; The first input terminal of the amplifier is connected with the first end of the sampling resistor; the second input terminal of the amplifier is connected with the second input terminal of the sampling resistor, and is used for amplifying the sampling voltage based on a preset gain; 4. The arc draw detection circuit of claim 3, wherein, The first input terminal of the comparator is connected with the output terminal of the amplifier; the second input terminal of the comparator is connected with a preset voltage threshold value; the output terminal of the comparator is connected with the input terminal of the control module, and is used for outputting the preset high level when the sampling voltage after the amplification is greater than the preset voltage threshold value; the preset voltage threshold value is a voltage value determined based on the preset current threshold value and the preset gain. The turns ratio of the primary coil to the secondary coil of the current transformer is greater than 1. The preset voltage threshold value is a voltage value determined based on the preset current threshold value, the preset gain and the turns ratio of the current transformer. The application further relates to a photovoltaic system.

5. The arc draw detection circuit of claim 4, wherein, ​ ​ 6. The arc detection circuit of claim 1, wherein, ​ An alarm circuit connected with an alarm signal output end of the control circuit, used for making arc alarm when receiving arc alarm signal; The control circuit is further used for outputting the arc alarm signal when the output current of the photovoltaic module is greater than the preset current threshold.

7. The arc draw detection circuit of claim 6, wherein, The alarm circuit comprises a sound alarm circuit and / or a light alarm circuit; The sound alarm circuit is used for making sound arc alarm when receiving the arc alarm signal; The light alarm circuit is used for making light arc alarm when receiving the arc alarm signal.

8. The arc draw detection circuit of claim 7, wherein, The sound alarm circuit comprises a buzzer and / or a loudspeaker; The light alarm circuit comprises an LED lamp and / or a display screen.

9. The arc detection circuit of any one of claims 1-8, wherein, The first positive end of the arc detection module is connected with the output positive end of N photovoltaic modules, and the second positive end is connected with the first positive end of a trip switch; N is a positive integer; The output negative ends of the N photovoltaic modules are connected with each other and connected with the first negative end of the trip switch.

10. A power supply system characterized by comprising: The arc detection circuit comprises the arc detection circuit according to any one of claims 1-9, and further comprises: The photovoltaic module, whose output positive end is connected with the first positive end of the arc detection circuit and whose output negative end is connected with the first negative end of a trip switch, is used for converting solar energy into electric energy and outputting direct current; The trip switch, whose first positive end is connected with the second positive end of the arc detection circuit, whose second positive end is connected with the input positive end of a voltage conversion module, and whose second negative end is connected with the input negative end of the voltage conversion module, is used for being turned off when the current between its first positive end and second positive end and the current between its first negative end and second negative end is greater than a preset protection current threshold; The voltage conversion module, whose control end is connected with the output end of the arc detection circuit and whose output end is connected with a load, is used for supplying power to the load after voltage conversion of the direct current output by the photovoltaic module.

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