Photovoltaic device having function of detecting arc in module

Abstract

The present invention relates to a photovoltaic device having the function of detecting an arc in a module and, more specifically, to a photovoltaic device in which a band-pass filter for separating arc components, a module arc detection unit for converting a separated signal into a DC signal, and a module control unit for recognizing the amount of arc generation are included in module control boards installed in photovoltaic modules, wherein a shutdown switch is driven when the recognized amount of arc generation is greater than a predetermined value, and the amount of arc generation of each of the photovoltaic modules is compared to display the location of arc generation.

Description

Solar power generation device with in-module arc detection function

[0001] The present invention relates to a solar power generation device having an arc detection function within a module.

[0002] As carbon dioxide emissions increase due to the use of petroleum raw materials, and as a result, global warming and abnormal weather phenomena become more frequent, much research is being conducted on eco-friendly energy sources that can reduce carbon dioxide emissions.

[0003] As one of these eco-friendly energy sources, photovoltaic (PV) devices are commercialized and are the focus of much research.

[0004] Solar power generation is achieved by connecting multiple devices to form a power generating device.

[0005] Figure 1 illustrates a solar power generation device having a conventional arc detection function.

[0006] Referring to FIG. 1, a solar power generation device includes a solar module (100) including solar cells, a connection board (300) that receives outputs of a plurality of solar modules (100) and converts them into alternating current, and an inverter (500).

[0007] The outputs of multiple solar modules (100) are connected in series and output to the +STRING and -STRING terminals, and the outputs connected in series in this way are input to the +STRING and -STRING terminals of the connection board (300).

[0008] After multiple STRINGS are input to the connection board (300) and switching and connection operations are performed, the direct current is converted into alternating current in the inverter (500).

[0009] Recent solar power generation devices have been equipped with a module control board (200) that includes a Rapid Shutdown (RSD) system. The Rapid Shutdown (RSD) system is designed to rapidly cut off the voltage generated by solar modules to prevent firefighters from being electrocuted in the event of a fire in a building where the power generation facility is installed, and is a safety regulation required by the National Electric Code (NEC).

[0010] The module control board (200) is installed in each solar module (100) to perform the RSD function and serves as a safety measure to prevent secondary accidents by lowering or blocking the output voltage in an emergency situation.

[0011] When a situation occurs that requires RSD operation, the inverter control unit (510) transmits an emergency blocking signal to the module communication unit (220) of each module control board (200) through the inverter communication unit (520).

[0012] An emergency blocking signal received from the module communication unit (220) is transmitted to the module control unit (210), and the module control unit (210) operates the shutdown switch (203).

[0013] As the adoption of solar power increases, concerns about the safety of power generation facilities are also growing. Recent research has shown that 90% of fires in solar power plants are caused by arcs caused by poor contact. Consequently, systems that detect and block arcs are being implemented in solar power plants.

[0014] There is a trend toward adding arc detectors or arc detection functions inside or outside the inverter for fire prevention.

[0015] Referring to Fig. 1, an inverter (500) includes an arc detection unit (530), and when the arc detection unit (530) detects an arc, the inverter control unit (510) blocks the output of the output switching unit (550).

[0016] However, this method only provides detection and blocking functions for safety measures in emergency situations, so there is a problem that the entire system must be inspected to determine where the arc occurred.

[0017] In addition, since all of the added module control boards (200) are connected by connectors, the probability of arc generation due to plasma discharge caused by poor connector contact increases.

[0018] Therefore, an arc detection function is required in the module control board (200) that can block the output of individual solar modules (100), and development of a technology that can identify the location of arc occurrence using arc occurrence information of each solar module (100) is also required.

[0019] The technical problem to be solved by the present invention is to provide a solar power generation device capable of identifying an arc generation location for a plurality of solar power modules.

[0020] The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0021] A solar power generation device having an arc detection function within a module of the present invention for solving the above technical problem includes a solar module, a module control board installed in the solar module, a connection plate for receiving the output of the solar module and converting it into alternating current, and an inverter, and the module control board may include a band-pass filter, a module arc detection unit, and a module control unit.

[0022] In some embodiments of the present invention, the low-pass cutoff frequency of the band-pass filter may be greater than the operating frequency of the module control board or the inverter.

[0023] In some embodiments of the present invention, the module arc detection unit may include an AC coupling terminal and a DC smoothing terminal that converts AC into DC.

[0024] In some embodiments of the present invention, the delay time constant of the DC smoothing stage may be 0.1 seconds or less.

[0025] In some embodiments of the present invention, the module control unit can drive a shutdown switch when the detected amount of the generated arc is greater than a set value.

[0026] In some embodiments of the present invention, the module control unit can transmit the detected amount of the generated arc to the inverter control unit.

[0027] In some embodiments of the present invention, the inverter may include an inverter control unit that communicates with the module control unit to receive an arc detection amount.

[0028] In some embodiments of the present invention, the inverter control unit can block the output of the output switching terminal by using the detected amount of the received arc.

[0029] In some embodiments of the present invention, the inverter control unit can compare the detected amount of the received arc and display the module number in the order of the detected amount on the display unit.

[0030] As described above, according to the solar power generation device having an arc detection function within the module of the present invention, the risk of fire can be reduced by detecting arc occurrence in an individual solar module and blocking the output of the module in which the arc occurred, and the location of the arc occurrence can be identified by comparing arc detection signals received from multiple module control boards, thereby facilitating maintenance of the power generation device.

[0031] Figure 1 illustrates a solar power generation device having a conventional arc detection function.

[0032] FIG. 2 illustrates a solar power generation device having an arc detection function according to one embodiment of the present invention.

[0033] Figure 3 illustrates the module arc detection unit in Figure 2.

[0034] Figure 4 illustrates a flow chart of a module control unit according to one embodiment of the present invention.

[0035] Figure 5 illustrates a flow chart of an inverter control unit according to one embodiment of the present invention.

[0036] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided only to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Like reference numerals designate like elements throughout the specification.

[0037] “And / or” includes each and every combination of one or more of the items mentioned.

[0038] The terminology used herein is for the purpose of describing embodiments only and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise. As used herein, the terms "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components, steps, operations, and / or elements mentioned.

[0039] Additionally, throughout the specification, when a part is said to be "connected" to another part, this includes not only cases where it is "directly connected," but also cases where it is "indirectly" or "electrically connected" with other members or components in between.

[0040] Additionally, throughout the specification, the description that each layer (film), region, pattern or structure is formed "on" or "under" the substrate, each layer (film), region, pad or pattern includes both being formed directly or through the interposition of another layer. The criteria for being on / over or under / under each layer are explained based on the drawings.

[0041] Additionally, expressions such as 'first, second', etc. are used only to distinguish between multiple components, and do not limit the order or other characteristics between the components.

[0042] Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used in their common sense to those of ordinary skill in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0043] Hereinafter, a solar power generation device having an arc detection function within a module according to the present invention will be described with reference to drawings.

[0044] FIG. 2 illustrates a solar power generation device having an arc detection function according to one embodiment of the present invention.

[0045] Referring to FIG. 2, a solar power generation device according to one embodiment of the present invention includes a solar module (100), a module control board (200) installed in the solar module (100), a connection board (300) that receives the output of the solar module (100) and converts it into alternating current, and an inverter (500). The module control board (200) may include a band-pass filter (207) that separates an arc component, a module arc detection unit (230) that smooths the separated signal into a DC signal, and a module control unit (210) that recognizes the amount of arc generation using the DC signal.

[0046] The above solar module (100) may be an array in which cells that generate direct current power corresponding to the received sunlight are arranged.

[0047] The output of the above solar module (100) is input to the module control board (200).

[0048] The direct current input to the module control board (200) passes through the shutdown circuit (201) and a low-pass filter (205) to remove noise components before being output.

[0049] The shutdown circuit (201) of the module control board (200) may include a shutdown switch (203) for performing an emergency shutdown function.

[0050] When a situation arises that requires an emergency shutdown operation, the module control unit (210) that receives an emergency shutdown signal from the inverter (500) can operate the shutdown switch (203) of the shutdown circuit unit (201).

[0051] The module control board (200) and the inverter (500) each include a module communication unit (220) and an inverter communication unit (520) for communication with each other, and the communication units (220, 520) can be connected wirelessly or by wire.

[0052] Wireless connections can be formed as WIFI networks, and wired connections can be formed as Power Line Communication (PLC) networks using power lines.

[0053] The outputs of multiple solar modules (100) are connected in series after passing through each module control board (200) and output to the +STRING and -STRING terminals, and the outputs connected in series in this way can be input to the +STRING and -STRING terminals of the connection board (300).

[0054] Multiple STRINGS can be input into the connection panel (300).

[0055] The above connection board (300) facilitates the connection of a large number of wires between a plurality of STRINGS formed by a module control board (200) connected to a solar module (100) and an inverter (500) and can perform various protective functions.

[0056] The above inverter (500) converts the direct current output from the connection board (300) into alternating current.

[0057] The inverter (500) may include an arc detection unit (530) and an inverter control unit (510) that controls an output switching unit (550) using the output of the arc detection unit (530). When the inverter control unit (510) detects an arc, it may operate the output switching unit (550) to block the output.

[0058] The above band pass filter (207) can separate the arc component from the output of the solar module (100).

[0059] The low-pass cutoff frequency of the band-pass filter (207) can be set to be greater than the operating frequency of the module control board (200) or the inverter (500).

[0060] Arcs generate random, high-frequency noise currents in cables used in solar power generation devices. Arcs can be observed as high-frequency noise in series-connected strings.

[0061] The current noise spectrum of the arc component is distributed up to several MHz, but the noise current density above 200 kHz varies depending on the cable structure of the device and may not match the actual arc occurrence component.

[0062] In addition, the operating frequency of the module control board (200) used in the solar power generation device and the switching frequency of the inverter (500) are usually operated at less than 50 kHz.

[0063] Therefore, the band pass filter (207) according to the present invention can set the high-pass cutoff frequency to 100 kHz and the low-pass cutoff frequency to 50 kHz.

[0064] However, the high-pass cutoff frequency may vary depending on the wiring structure design of the device, and the low-pass cutoff frequency may be set differently depending on the operating frequency of the device.

[0065] The output of the bandpass filter (207) can be input to the module arc detection unit (230).

[0066] Fig. 3 illustrates a module arc detection unit according to Fig. 2.

[0067] Referring to FIG. 3, the module arc detection unit (230) according to the present invention may include a first capacitor (C1) used for AC coupling to separate only the arc noise component of the high-frequency component, a DC smoothing stage that converts the high-frequency noise component into DC, and a filter for noise removal.

[0068] The above DC smoothing circuit can be formed by a charge / discharge circuit formed by a first diode (D1), a second resistor (R2), and a second capacitor (C2).

[0069] The above charging / discharging circuit should preferably be set to a time that can ignore temporary high-frequency noise such as spark components and at the same time avoid arc detection being delayed due to delay.

[0070] Therefore, in one embodiment of the present invention, the charge / discharge time constant (t = RC) can be set to 0.1 seconds. With this setting, arc occurrence can be detected within 0.1 seconds after arc occurrence.

[0071] For example, the capacitance of the second resistor (R2) can be 20 kΩ, and the capacitance of the second capacitor (C2) can be 4.7 uF.

[0072] The above noise removal filter is composed of a first resistor (R1) and a third capacitor (C3), and can protect the input terminal of the microcontroller (MCU) built into the module control unit (210).

[0073] A second diode (D2) in Fig. 3 may be added to protect the circuit by bypassing high surge voltage.

[0074] The output voltage of the noise removal filter can be input to a microcontroller (MCU) and converted into a digital detection value by an ADC (Analog to Digital Converter) formed inside the microcontroller (MCU).

[0075] Referring to FIG. 2, the module control board (200) may include a module control unit (210), and the inverter (500) may include an inverter control unit (510).

[0076] The above module control unit (210) and inverter control unit (510) may each include a microcontroller (MCU) and a memory, and may perform control operations of the solar power generation device according to the present invention by the microcontroller (MCU) that executes a program stored in the memory.

[0077] The module control unit (210) is connected to the module communication unit (220), the inverter control unit (510) is connected to the inverter communication unit (520), and the communication units (220, 520) can communicate with each other by being connected wirelessly or by wire.

[0078] FIG. 4 illustrates a flow chart of a module control unit according to one embodiment of the present invention, and FIG. 5 illustrates a flow chart of an inverter control unit according to one embodiment of the present invention.

[0079] First, referring to Fig. 4, the operation of the module control unit (210) is described.

[0080] The microcontroller (MCU) of the module control unit (210) checks whether an arc is detected.

[0081] When an arc is detected and the detection amount is greater than the set value, the shutdown switch (203) is driven and the detection amount is transmitted to the inverter control unit (510).

[0082] If an arc is detected but the detection amount is less than the set value, the shutdown switch (203) is not operated and the detection amount is transmitted to the inverter control unit (510).

[0083] That is, if the detected amount of the generated arc is greater than the set value, the module control unit (210) drives the shutdown switch (203) and transmits the detected amount of the generated arc to the inverter control unit.

[0084] The above setting value can be determined by taking into account the output specifications of the solar module (100), etc.

[0085] In this way, the amount of arc generation is detected within 0.1 second, and the output of the solar module (100) is immediately blocked upon detection to prevent it from being transmitted to the STRING terminal, and the generation information including the amount of detection can be shared in real time with the inverter control unit (510).

[0086] Referring to the following Figure 5, the operation of the inverter control unit (510) is described.

[0087] It is confirmed whether the arc detection amount has been received from the microcontroller (MCU) of the inverter control unit (510).

[0088] When an arc detection amount is received and the detection amount is greater than a set value, the output of the output switch (550) is blocked, and the size of the detection amount of each solar module (100) is compared for multiple solar modules, and the module numbers of the first and second sizes are displayed on the display unit (570).

[0089] If an arc detection amount is received but the detection amount is less than the set value, the output of the output switch (550) is not blocked, and the size of the detection amount of each solar module (100) is compared for multiple solar modules, and the module numbers of the first and second sizes are displayed on the display unit (570).

[0090] That is, the inverter control unit (510) blocks the output of the inverter (500) when the amount of detected arc received is greater than the set value, and displays the unique number of the solar module (100) in which the arc occurrence was detected.

[0091] The manager of the power generation device can quickly identify the point of arc occurrence by checking the unique number of the solar module (100) where arc occurrence was detected, and can easily perform follow-up work for recovery.

[0092] The above setting value may be determined considering the overall system capacity or load of the solar power generation device. In one embodiment of the present invention, a case in which a single detection amount is exceeded is described as an example, but in reality, the output may be cut off when multiple values ​​simultaneously exceed the setting value.

[0093] In this way, according to the solar power generation device of the present invention, the risk of fire can be reduced by detecting arc occurrence in an individual solar module and blocking the output of the module in which the arc occurred, and the location of the arc occurrence can be identified and confirmed by comparing arc detection signals received from multiple module control boards, thereby facilitating maintenance of the power generation device.

[0094] Although the present invention has been described as above, those skilled in the art will recognize that the present invention can be implemented in other forms while maintaining the technical spirit and essential features of the present invention.

[0095] The scope of the present invention will be defined by the patent claims, but it should be interpreted that not only the configuration directly derived from the description of the patent claims, but also all changes or modified forms derived from equivalent configurations are included in the scope of the present invention.

Claims

1. Solar modules; A module control board installed on the above solar module; and It includes a connection board and an inverter that receive the output of the above solar module and convert it into AC, The above module control board is a solar power generation device including a band pass filter, a module arc detection unit, and a module control unit.

2. In paragraph 1, A solar power generation device in which the low-pass cutoff frequency of the above band-pass filter is greater than the operating frequency of the module control board or the inverter.

3. In paragraph 1, A solar power generation device, wherein the above module arc detection unit includes an AC coupling terminal and a DC smoothing terminal that converts AC into DC.

4. In paragraph 3, A solar power generation device having a delay time constant of the above DC smoothing stage of 0.1 seconds or less.

5. In paragraph 1, A solar power generation device in which the above module control unit operates a shutdown switch when the detected amount of the generated arc is greater than a set value.

6. In paragraph 1, A solar power generation device in which the above module control unit transmits the detected amount of the generated arc to the inverter control unit.

7. In paragraph 1, A solar power generation device, wherein the inverter includes an inverter control unit that communicates with the module control unit and receives an arc detection amount.

8. In paragraph 7, The above inverter control unit is a solar power generation device that blocks the output of the output switching terminal by using the detected amount of the received arc.

9. In paragraph 7, The above inverter control unit is a solar power generation device that compares the detected amount of received arcs and displays the module number in the order of the detected amount on the display unit.

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