MLPE device for preventing fire damage to photovoltaic module and control method thereof

Abstract

An MLPE device for preventing fire damage to a photovoltaic module according to an aspect of the present disclosure may comprise: switching elements, each installed between a photovoltaic string and an inverter, and, on the basis of control signals, connecting or insulating the photovoltaic strings and inverter; and comparators outputting control signals based on the comparison of the voltage at the front and rear ends of the switching elements.

Description

MLPE device for preventing damage to solar modules and its control method

[0001] The present invention relates to an MLPE device for preventing damage to a solar module and a method for controlling the same, and more particularly, to an MLPE device for preventing damage to a solar module used in a solar system and a method for controlling the same.

[0002] With the recent rise in interest in eco-friendly energy technologies, the installation of solar power generation systems, which utilize sunlight to generate energy, is on the rise. Solar power systems generate electricity by collecting solar energy through photovoltaic modules. This electricity is then fed into the home's power grid for household use or stored in batteries for later use. Solar power generation systems are gaining popularity due to their environmental friendliness and potential long-term savings on electricity bills.

[0003] Typically, a solar power generation system has multiple photovoltaic (PV) modules installed, and each PV module has one MLPE (Module-Level Power Electronics) or monitoring module installed. However, in some cases, MLPEs or monitoring modules are not installed. Multiple PV modules can form a single PV string, and a PV system that includes multiple PV strings and MLPEs or monitoring modules connected to an inverter may generate reverse current due to voltage imbalances between each PV string. When reverse current occurs, reverse current flows to the MLPE, which causes the MLPE to malfunction and acts as a factor that lowers the power generation efficiency of the PV system. Therefore, various studies are ongoing to prevent reverse current in PV systems while increasing the efficiency of solar power generation.

[0004] The technical problem to be solved by the present invention is to provide an MLPE device that prevents damage to a solar module due to reverse current.

[0005] Another technical challenge to be solved by the present invention is to provide an MLPE device that can contribute to improving the power generation efficiency and safety of a solar power generation system while minimizing power consumption and heat generation.

[0006] In order to solve the above-described problem of the present invention, an MLPE device for preventing damage to a solar module according to an embodiment of the present invention may include a switching element installed between each solar string and an inverter, and connecting or insulating each solar string and the inverter based on a control signal; and a comparator outputting the control signal based on a result of comparing a voltage at a front end and a voltage at a rear end of the switching element.

[0007] In the present invention, the MLPE device for preventing damage to the solar module may include an insulated converter that generates and outputs an insulated voltage.

[0008] In the present invention, the MLPE device for preventing damage to the solar module may include an overvoltage protection circuit that applies the voltage generated from each solar string to the insulated converter based on whether the voltage generated from each solar string is overvoltage.

[0009] In the present invention, the comparator may be characterized in that it is driven by receiving an isolated voltage output from the insulated converter.

[0010] In the present invention, the comparator may be characterized in that it outputs the control signal for turning off the switching element when the voltage of the front end of the switching element is lower than the voltage of the rear end, and outputs the control signal for turning on the switching element when the voltage of the front end of the switching element is higher than the voltage of the rear end.

[0011] In the present invention, the switching element may be characterized in that it insulates each solar string and the inverter based on the off control signal, and connects each solar string and the inverter based on the on control signal.

[0012] A method for controlling an MLPE device for preventing damage to a solar module according to another embodiment may include a step of detecting a voltage at a front end and a voltage at a rear end of a switching element; and a step of controlling the switching element based on a comparison result between the voltage at the front end and the voltage at the rear end of the switching element.

[0013] In the present invention, the detecting step may include a step of connecting a plurality of solar modules in series to form a plurality of solar strings; and a step of applying a voltage generated in each solar string to the switching element.

[0014] In the present invention, the controlling step may include a step of turning off the switching element so that each solar string and the inverter are insulated when the voltage of the front end of the switching element is lower than the voltage of the rear end, and turning on the switching element so that each solar string and the inverter are connected when the voltage of the front end of the switching element is higher than the voltage of the rear end.

[0015] In the present invention, the controlling step may include a step of generating an isolated voltage based on whether the voltage generated from each solar string is overvoltage, and applying the isolated voltage to a comparator to compare the voltage at the front end and the voltage at the rear end of the switching element.

[0016] According to one embodiment of the present invention, damage to MLPE due to reverse current can be prevented.

[0017] Additionally, it can contribute to improving the power generation efficiency and safety of solar power generation systems while minimizing power consumption and heat generation.

[0018] In addition, since the signal for controlling the switching element inside the PV line of the solar power system is output, the configuration of the solar power generation system can be simplified by eliminating the device outside the PV line for transmitting the control signal.

[0019] FIG. 1 is an exemplary drawing for explaining a solar power generation system according to one embodiment.

[0020] FIG. 2 is an exemplary drawing for explaining a solar power generation system with an added diode according to one embodiment.

[0021] FIG. 3 is an exemplary drawing for explaining a solar power generation system with an added switching element according to one embodiment.

[0022] FIG. 4 is an exemplary drawing for explaining the configuration of an MLPE device for preventing damage to a solar module according to one embodiment.

[0023] FIG. 5 is an exemplary drawing for explaining a control method of an MLPE device for preventing damage to a solar module according to one embodiment.

[0024] FIG. 6 is an exemplary drawing for explaining a control method of an MLPE device for preventing damage to a solar module according to one embodiment.

[0025] FIG. 7 is an exemplary drawing showing the configuration of a plurality of solar module strings and a control unit according to one embodiment.

[0026] FIG. 8 is an exemplary drawing showing a configuration in which a plurality of solar modules are equipped with micro inverters according to one embodiment.

[0027] FIG. 9 is a drawing for reference in explaining a power supply structure of a building in which a solar module according to one embodiment of the present invention is installed.

[0028] An MLPE device for preventing damage to a solar module according to one aspect of the present invention may include a switching element installed between each solar string and an inverter, which connects or insulates each solar string and the inverter based on a control signal, and a comparator that outputs a control signal based on a result of comparing a voltage at a front end and a voltage at a rear end of the switching element.

[0029] 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 together with the accompanying drawings. However, the present invention is not limited to the embodiments presented below, but may be implemented in various different forms, and it should be understood that it includes all transformations, equivalents, and substitutes included in the spirit and technical scope of the present invention. The embodiments presented below are provided 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. In describing the present invention, if a detailed description of a related known technology is judged to obscure the gist of the present invention, the detailed description thereof will be omitted.

[0030] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The appearance of phrases such as "in some embodiments" or "in one embodiment" in various places in this specification does not necessarily all refer to the same embodiment. The singular expression includes plural expressions unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprises" or "has" specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0031] Additionally, the connecting lines or connecting members between components depicted in the drawings are merely exemplary representations of functional connections and / or physical or circuit connections. In an actual device, connections between components may be represented by various functional connections, physical connections, or circuit connections that may be replaced or added.

[0032] These embodiments may be modified in various ways and may take on various forms. Therefore, some embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit these embodiments to a specific disclosed form, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of these embodiments. The terminology used herein is solely for the purpose of describing the embodiments and is not intended to limit these embodiments.

[0033] Unless otherwise defined, the terms used in these examples have the same meaning as commonly understood by those of ordinary skill in the technical field to which these examples pertain. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or overly formal sense unless explicitly defined in these examples.

[0034] The following detailed description of the present invention refers to the accompanying drawings, which illustrate specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention, while different from each other, are not necessarily mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be modified and implemented from one embodiment to another without departing from the spirit and scope of the present invention. Furthermore, it should be understood that the positions or arrangements of individual components within each embodiment may also be modified without departing from the spirit and scope of the present invention. Accordingly, the following detailed description is not to be taken in a limiting sense, and the scope of the present invention is to be construed to encompass the scope of the claims and all equivalents thereof. Like reference numerals in the drawings represent the same or similar elements throughout the several aspects.

[0035] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that a person having ordinary skill in the art to which the present invention pertains can easily practice the present invention.

[0036]

[0037] FIG. 1 is an exemplary drawing for explaining a solar power generation system according to one embodiment.

[0038] A solar power generation system (100) according to the present embodiment may refer to a power generation system that converts solar energy into electrical energy. The solar power generation system may include a plurality of solar modules (Photovoltaics Modules; PV Modules) (11 to 10n, 21 to 20n, 31 to 30n, 41 to 41n), and each solar module may include an MLPE (Module Level Power Electronics) device that converts the generated energy. The MLPE device may be an optimizer or a micro inverter. As an example, when the MLPE device is an optimizer, the MLPE device may control the power generated from the plurality of solar modules and output it to an inverter (e.g., a solar string inverter) (110). The current converted by the inverter (110) (e.g., converting direct current into alternating current) may be output to a load or a grid. As another example, if the MLPE device is a microinverter, the MLPE device can convert power generated from multiple solar modules. The current converted by the MLPE device can be output to a load or the grid. For convenience of explanation, the present specification mainly describes an embodiment in which the MLPE device regulates power generated from solar modules and outputs it to a solar string inverter, assuming that the MLPE device is a DC optimizer, but is not limited thereto.

[0039] Referring to FIG. 1, a solar power generation system (100) according to one embodiment of the present invention may include a plurality of photovoltaic modules (11 to 10n, 21 to 20n, 31 to 30n, 41 to 41n) and an inverter (110).

[0040] A solar module is a module that generates electricity using the photovoltaic effect. As illustrated in FIG. 1, a plurality of solar modules may be interconnected to form a photovoltaic string (10 to 40). Specifically, a plurality of solar modules may be connected in series to form a single photovoltaic string. Additionally, a plurality of solar strings may be connected in parallel to form a photovoltaic module array. For convenience of explanation, an example in which two photovoltaic strings form a single photovoltaic module will be described below, but the present invention is not limited thereto.

[0041] A plurality of solar strings are connected to a control device (not shown) to transmit and receive data. The plurality of solar strings can transmit and receive data with the control device via power line communication (PLC). The control device can receive data from the plurality of solar modules and solar strings by transmitting and receiving data with the plurality of solar modules and solar strings through power lines. Even without having multiple controllers for collecting data from the solar strings or individual solar modules, the control device can improve complex communication structures by directly receiving and processing multiple data by being connected to the plurality of solar strings through a coupling unit.

[0042] The control device can check the operating status and control the operation of each solar string. In addition, the control device can check the operating status of each individual solar module and control its operation. The control device can quickly process data from the solar string and individual solar modules. The control device can monitor the power generation and operating status of the solar module based on data received from the solar module. The control device can receive a fault signal through the MLPE device of the solar module and check for a fault in the solar module. For example, if a fault occurs in a solar module, the control device can quickly transmit a control signal corresponding to operation or stop to the corresponding solar module based on the operating status. In addition, if a fault occurs in an individual solar module, the control device can individually control the solar module.

[0043] Meanwhile, power line communication can refer to a communication method that transmits data using power lines (cables) that supply electricity. Power line communication can refer to a technology that transmits data by conveying frequency signals via power lines that supply electricity. Power line communication can be categorized into high-speed and low-speed based on speed, and high-voltage and low-voltage based on voltage. For example, home solar modules and control devices can communicate using power signals of 50-60 Hz. Furthermore, other embodiments may utilize other frequency bands.

[0044] A plurality of solar strings (10 to 40) may each be connected to a converter (not shown), and the plurality of converters may be connected to an inverter (110). The inverter (110) may combine and convert energy generated from a plurality of solar modules and solar strings. At this time, the inverter (110) may be connected one-to-one to each of the plurality of solar strings, or a plurality of solar strings may be connected to one inverter (110). However, for the convenience of explanation, an example in which a plurality of solar strings are connected to a single inverter (110) will be described below, but the present invention is not limited thereto.

[0045] The inverter (110) may include one or more Maximum Power Point Tracking Blocks (MPPT blocks) (111 and 112). The MPPT blocks (111 and 112) can track the maximum power point (MPP) of the solar module in real time and control the solar power generation system (100) so that the output power of the solar module is maximized. A plurality of solar strings may be connected to one MPPT block, but for the convenience of explanation, an example in which two solar strings are connected to one MPPT block will be described below, but the present invention is not limited thereto.

[0046] For example, the first solar string (10) and the second solar string (20) of the solar power generation system (100) may be connected to the first MPPT block (111), and the third solar string (30) and the fourth solar string (40) may be connected to the second MPPT block (112). Each of the first solar string (10) and the second solar string (20) may be connected to the first MPPT block (111) via a positive (+) cable (120), and each of the third solar string (30) and the fourth solar string (40) may be connected to the second MPPT block (112) via a positive (+) cable (120). Additionally, each of the first solar string (10) and the second solar string (20) can be connected to the first MPPT block (111) via a negative (-) cable (130), and each of the third solar string (30) and the fourth solar string (40) can be connected to the second MPPT block (112) via a negative (-) cable (130).

[0047] When two or more solar strings are connected to a single MPPT block, a potential difference may occur depending on the voltage situation of each solar string, which may result in a constant current or a reverse current. The reverse current is a current that flows in the opposite direction to the normal current direction, and may damage or destroy components within the solar power generation system (100), thereby reducing the efficiency of the solar power generation system (100) and causing damage to the system. The potential difference may refer to a factor that determines the direction in which the current flows, and while it is common for the current to flow from a high potential to a low potential, a reverse current may occur under certain conditions.

[0048] Specifically, if the voltages of two solar strings connected to one MPPT block are the same or have a slight difference below a preset value, a constant current may occur, and the solar power generation system (100) may operate normally. If the voltage difference between two solar strings connected to one MPPT block is greater than a preset value, a reverse current may occur, and the solar power generation system (100) may operate abnormally.

[0049] For example, if the voltages of the first solar string (10) and the second solar string (20) connected to the first MPPT block (111) have a slight difference below a preset value and the potential difference is not large, a constant current may be generated, and the current generated in the first solar string (10) and the second solar string (20) may flow to the DC-DC converter (DC / DC Converter) of the first MPPT block (111) in the inverter (110).

[0050] For example, if the voltage of the third solar string (30) connected to the second MPPT block (112) is greater than the voltage of the fourth solar string (40) by a preset value or more, a reverse current may occur due to the large potential difference, and the current generated in the third solar string (30) may not flow to the DC-DC converter (DC / DC Converter) of the second MPPT block (112) in the inverter (110), but may flow to the fourth solar string (40), so that the solar power generation system (100) may operate abnormally.

[0051] For example, if the voltage of the third solar string (30) connected to the second MPPT block (112) is lower than the voltage of the fourth solar string (40) by a preset value or more, a reverse current may occur due to a large potential difference, and the current generated in the fourth solar string (40) may not flow to the DC-DC converter (DC / DC Converter) of the second MPPT block (112) in the inverter (110), but may flow to the third solar string (30), so that the solar power generation system (100) may operate abnormally.

[0052] Because reverse current generated by a large potential difference may cause damage to the MLPE device within each solar module, there is a need to prevent the occurrence of reverse current.

[0053]

[0054] FIG. 2 is an exemplary diagram illustrating a solar power generation system with an added diode according to one embodiment. In the following description, any portions that overlap with the description of FIG. 1 will be omitted.

[0055] Referring to FIG. 2, the solar power generation system (100) may include diodes (211 to 214) to prevent the occurrence of reverse current.

[0056] The diodes (211 to 214) can be installed inside or outside the inverter (110), and for convenience of explanation, an example in which the diodes (211 to 214) are installed on the positive (+) cable (120) outside the inverter (110) will be described below, but the present invention is not limited thereto.

[0057] In one embodiment, a first diode (211) may be installed on the positive (+) cable (120) connected to the first solar string (10), a second diode (212) may be installed on the positive (+) cable (120) connected to the second solar string (20), a third diode (213) may be installed on the positive (+) cable (120) connected to the third solar string (30), and a fourth diode (214) may be installed on the positive (+) cable (120) connected to the fourth solar string (40).

[0058] Diodes (211 to 214) are structures in which a P-type semiconductor and an N-type semiconductor are joined, and the direction in which current flows can be determined depending on the voltage. Specifically, diodes (211 to 214) are elements or semiconductors designed to allow forward current to flow and prevent reverse current from flowing, thereby preventing reverse current from flowing in the circuit, thereby preventing element damage, circuit malfunction, energy loss, etc.

[0059] Specifically, when the voltages of two solar strings connected to one MPPT block are the same or have a slight difference of less than or equal to a preset value, a constant current may occur, and the diodes (211 to 214) can control the current generated from the solar string to flow to the MPPT block in the inverter, and the solar power generation system (100) can operate normally. When the difference in the voltages of two solar strings connected to one MPPT block is greater than or equal to a preset value, a reverse current may occur, and the diodes (211 to 214) can control the current generated from the solar string to not flow to the other solar string, and the solar power generation system (100) can operate normally.

[0060] For example, if the voltages of the first solar string (10) and the second solar string (20) connected to the first MPPT block (111) have a slight difference below a preset value and the potential difference is not large, a constant current may be generated, and the first diode (211) and the second diode (212) may control the current generated in the first solar string (10) and the second solar string (20) to flow to the DC-DC converter (DC / DC Converter) of the first MPPT block (111) in the inverter (110).

[0061] For example, if the voltage of the third solar string (30) connected to the second MPPT block (112) is greater than the voltage of the fourth solar string (40) by a preset value or more, a reverse current may occur due to the large potential difference, and the fourth diode (214) can control the current generated in the third solar string (30) not to flow to the fourth solar string (40), and can control the current generated in the third solar string (30) to flow to the DC-DC converter (DC / DC Converter) of the second MPPT block (112) in the inverter (110). Therefore, the solar power generation system (100) can be operated normally.

[0062] For example, if the voltage of the third solar string (30) connected to the second MPPT block (112) is lower than the voltage of the fourth solar string (40) by a preset value or more, a reverse current may occur due to a large potential difference, and the third diode (213) can control the current generated in the fourth solar string (40) not to flow to the third solar string (30), and can control the current generated in the fourth solar string (40) to flow to the DC-DC converter (DC / DC Converter) of the second MPPT block (112) in the inverter (110). Therefore, the solar power generation system (100) can be operated normally.

[0063] Meanwhile, due to the power consumption of the diodes (211 to 214), the power generation efficiency of the solar power generation system (100) may decrease, and heat may be generated due to power loss by the diodes (211 to 214), so additional heat dissipation measures may be required.

[0064]

[0065] FIG. 3 is an exemplary diagram illustrating a solar power generation system with an added switching element according to one embodiment. In the following description, any portions that overlap with the descriptions of FIGS. 1 and 2 will be omitted.

[0066] Referring to FIG. 3, the solar power generation system (100) may include MLPE devices (311 to 314) to prevent damage to solar modules and to prevent the occurrence of reverse current. MLPE device to prevent damage to solar modules MLPE device to prevent damage to solar modules MLPE devices (311 to 314) to prevent damage to solar modules may refer to MLPE devices including an electronic circuit in which diodes (211 to 214) are replaced with switching elements having low conduction resistance.

[0067] Conduction resistance can refer to the resistance generated in a switching element when the switching element is in the on state. A lower conduction resistance can reduce the loss of power passing through the switching element, thereby increasing the efficiency of the solar power generation system (100).

[0068] The switching element according to one embodiment of the present invention may be, but is not limited to, a metal oxide semiconductor field effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), a silicon carbide MOSFET (SiC MOSFET), a gallium nitride high electron mobility transistor (GaN HEMT), or the like.

[0069] MOSFET can refer to a transistor that controls the current between the drain terminal and the source terminal by applying voltage to the gate terminal, IGBT can refer to a transistor that combines the advantages of a MOSFET and a bipolar junction transistor (BJT), SiC MOSFET can refer to a MOSFET based on silicon carbide, and GaN HEMT can refer to a high-electron mobility transistor based on gallium nitride.

[0070] Meanwhile, a relay may be used to block the solar power generation system (100) and prevent reverse current. In this case, the solar power generation system (100) may require a separate junction box or device outside the power line (cable), which may complicate the configuration of the solar power generation system (100). Furthermore, by the time the circuit for blocking current or preventing reverse current is activated, the MLPE device may already be damaged.

[0071] The solar power generation system (100) with the switching element added according to the present invention has the advantage of being simple in configuration compared to the method of blocking the solar power generation system (100) and preventing reverse current through a relay, since no additional device for preventing reverse current is installed outside the power line (cable).

[0072]

[0073] FIG. 4 is an exemplary diagram illustrating the configuration of an MLPE device for preventing damage to a solar module according to one embodiment. In the following description, any portions that overlap with the descriptions of FIGS. 1 to 3 will be omitted.

[0074] Referring to FIG. 4, the MLPE device (311 to 314) for preventing damage to a solar module may include a switching part (410), a high voltage protection circuit (420), an isolation converter (430), and a comparator (440).

[0075] A switching element (410) can be installed between one solar string and an inverter (110), and can connect or insulate each solar string and inverter (110) based on a control signal.

[0076] The overvoltage protection circuit (420) can apply the voltage generated from the solar string to the insulated converter (430) based on whether the voltage generated from the solar string is overvoltage.

[0077] An isolated converter (430) may refer to a DC-DC converter that generates and outputs an isolated voltage.

[0078] The comparator (440) can output a control signal based on the result of comparing the voltage of the front end (411) and the voltage of the rear end (412) of the switching element (410). The comparator (440) can be driven by receiving an insulated voltage output from the insulated converter (430). The comparator (440) can output a control signal to turn off the switching element (410) when the voltage of the front end (411) of the switching element (410) is lower than the voltage of the rear end (412), and can output a control signal to turn on the switching element (410) when the voltage of the front end (411) of the switching element (410) is higher than the voltage of the rear end (412).

[0079] The switching element (410) can insulate the solar string and the inverter (110) based on an off control signal, and can connect the solar string and the inverter (110) based on an on control signal.

[0080]

[0081] FIG. 5 is an exemplary diagram illustrating a control method for an MLPE device to prevent damage to a solar module according to one embodiment. In the following description, any portions that overlap with the descriptions of FIGS. 1 to 4 will be omitted.

[0082] Referring to FIG. 5, in step 501, the MLPE devices (311 to 314) for preventing damage to the solar module can detect the voltage of the front end (411) and the voltage of the rear end (412) of the switching element (410). At this time, a plurality of solar modules can be connected in series to form a plurality of solar strings, and each solar string can be connected to the inverter (110) via a positive (+) cable (120) and a negative (-) cable (130). The MLPE devices (311 to 314) for preventing damage to the solar module can apply the voltage generated in each solar string to the switching element (410).

[0083] Specifically, the switching element (410) may be in an On state when the solar power generation system (100) is initially started or is operating normally. When the switching element (410) is in an On state, the switching element (410) may short-circuit the connection between the solar string and the inverter (110). Before the inverter (110) is started, the solar module or the solar string may reach a preset voltage, and in response to the solar module or the solar string reaching the preset voltage, the insulated converter (430) may output an insulated voltage. At this time, the overvoltage protection circuit (420) may prevent the insulated converter (430) from being damaged due to the overvoltage.

[0084] Meanwhile, the isolated voltage output from the insulated converter (430) can be applied as a voltage to drive the comparator (440). The comparator (440) receiving the voltage can constantly detect the voltage of the front end (411) and the voltage of the rear end (412) of the switching element (410).

[0085] In step 502, the MLPE device (311 to 314) for preventing damage to the solar module can control the switching element (410) based on the comparison result of the voltage of the front end (411) and the voltage of the rear end (412) of the switching element (410).

[0086] Specifically, the comparator (440) can output a control signal to open the switching element (410) when the voltage of the front end (411) of the switching element (410) is lower than the voltage of the rear end (412), and based on the opening control signal, the switching element (410) can insulate the solar string and the inverter (110). The comparator (440) can output a control signal to short-circuit the switching element (410) when the voltage of the front end (411) of the switching element (410) is higher than the voltage of the rear end (412), and based on the short-circuiting control signal, the switching element (410) can connect the solar string and the inverter (110). Through this, the MLPE device (311 to 314) for preventing damage to the solar module can prevent the occurrence of reverse current, and due to the low conduction resistance of the switching element (410), reverse current can be prevented with less power consumption and less heat generation compared to the diode (211 to 214).

[0087] Meanwhile, the overvoltage protection circuit (420) can apply the voltage generated from the solar string to the insulated converter (430) based on whether the voltage generated from the solar string is overvoltage, and the insulated converter (430) can generate an isolated voltage and apply it to the comparator (440). The comparator (440) can receive the isolated voltage and detect and compare the voltage of the front end (411) and the voltage of the rear end (412) of the switching element (410).

[0088] Meanwhile, the MLPE device (311 to 314) for preventing damage to the solar module according to the present invention can independently monitor the voltage of the solar string and control the switching element (410) based on the monitored result. In addition, since the control signal for controlling the switching element (410) can be output from the comparator (440), there is an advantage in that an external device for transmitting and receiving the control signal is not required.

[0089]

[0090] FIG. 6 is an exemplary drawing for explaining a control method of an MLPE device for preventing damage to a solar module according to one embodiment.

[0091] Referring to FIG. 6, in step 601, the solar power generation system (100) can form multiple solar strings by connecting multiple solar modules in series.

[0092] In step 602, the MLPE device (311 to 314) for preventing damage to the solar module can apply the voltage generated from the solar string to the switching element.

[0093] In step 603, the MLPE device (311 to 314) for preventing damage to the solar module can detect the voltage at the front and rear ends of the switching element.

[0094] In step 604, the MLPE device (311 to 314) for preventing damage to the solar module can check whether the voltage at the front end of the switching element is higher than the voltage at the rear end of the switching element.

[0095] In step 605, the MLPE device (311 to 314) for preventing damage to the solar module can insulate the solar string and the inverter by turning off the switching element when the voltage at the front end of the switching element is not higher than the voltage at the rear end of the switching element.

[0096] In step 606, the MLPE device (311 to 314) for preventing damage to the solar module can turn on the switching element to connect the solar string and the inverter when the voltage at the front end of the switching element is higher than the voltage at the rear end of the switching element.

[0097]

[0098] FIG. 7 is an exemplary drawing showing the configuration of a plurality of solar module strings and a control unit according to one embodiment.

[0099] As illustrated in FIG. 7, a plurality of photovoltaic modules (711 to 710n, 721 to 720n, 731 to 730n) can be interconnected to form a photovoltaic module string (710, 720, 730).

[0100] Multiple solar modules can be connected by power lines (740).

[0101] Each photovoltaic module string can be connected to a photovoltaic inverter (750) (751 to 753). The photovoltaic inverter (750) can convert energy generated by the photovoltaic module string (710, 720, 730) into alternating current power.

[0102] In addition, a plurality of photovoltaic module strings (710, 720, 730) are each connected to a control unit (760) to transmit and receive data. The plurality of photovoltaic modules can transmit and receive data with the control unit (760) via power line communication (PLC).

[0103] Power line communication may include a communication method that transmits data using power lines (cables) that supply electricity. Power line communication may include a technology that transmits data by carrying a frequency signal through the power lines that supply electricity. Power line communication can be categorized into high-speed and low-speed based on speed, and high-voltage and low-voltage based on voltage. For example, household solar modules and devices can communicate using power signals of 50-60 Hz. Furthermore, other embodiments may utilize other frequency bands.

[0104] A first photovoltaic module string (710) may include a plurality of photovoltaic modules of a first group (711 to 710n). In addition, the first photovoltaic module string (710) may be connected to a first photovoltaic inverter (751).

[0105] The second photovoltaic module string (720) may include a plurality of photovoltaic modules of a second group (721 to 720n) that are connected in series with each other. In addition, the second photovoltaic module string (720) may be connected to a second photovoltaic inverter (752).

[0106] The third photovoltaic module string (730) may include a plurality of photovoltaic modules of a third group (731 to 730n) that are connected in series with each other. In addition, the third photovoltaic module string (730) may be connected to a third photovoltaic inverter (753).

[0107] In the drawing, the photovoltaic module string is depicted as a plurality of photovoltaic modules connected in series, but may also include photovoltaic modules connected in parallel.

[0108] A plurality of solar modules (711 to 710n, 721 to 720n, 731 to 730n) are each connected to a converter (not shown), and the plurality of converters can be connected to a solar inverter (750).

[0109] The solar inverter (750) and control unit (760) can be connected to multiple solar modules (PhotoVoltaic Module) and solar module strings (PhotoVoltaic Module String) through the same power line (740).

[0110] A solar inverter (750) can convert energy generated from multiple photovoltaic modules and photovoltaic module strings by adding them together.

[0111]

[0112] FIG. 8 is an exemplary diagram illustrating a configuration in which a plurality of solar modules are equipped with microinverters according to one embodiment. In the following description, any portions that overlap with the descriptions of FIGS. 1 to 7 will be omitted.

[0113] As illustrated in FIG. 8, a plurality of photovoltaic modules (811 to 810n, 821 to 820n, 831 to 830n) may include a power conversion device (850). In this case, the power conversion device (850) may be a module level power electronics (MLPE). For example, if the solar power generation system (100) is an alternating current (AC)-based system, the MLPE may include a micro inverter, and if the solar power generation system (100) is a direct current (DC)-based system, the MLPE may include an optimizer.

[0114]

[0115] FIG. 9 is a drawing for reference in explaining a power supply structure of a residential building in which a solar module according to one embodiment of the present invention is installed.

[0116] As shown in Fig. 9, a photovoltaic module (2) can be installed on the roof of a building to generate energy.

[0117] A solar inverter (6) can convert the energy of a solar module (2) and supply generated power into a building (1).

[0118] Meanwhile, commercial power transmitted through the power line (3) can be supplied to the building through the transformer (4).

[0119] A plurality of home appliances (7) can be operated by selectively receiving power from at least one of commercial power or power generated by a solar module (2). The power meter (5) can measure the amount of power consumed in the building (1).

[0120] Additionally, if a separate energy storage system (ESS) is provided, the energy of the solar module (2) can be stored in the energy storage system (ESS).

[0121] When a plurality of solar modules (2) are connected, a solar module string can be formed. A solar module string is an assembly of a plurality of solar modules (Phtovoltaics Modules) and can include one output terminal.

[0122] Meanwhile, the photovoltaic module (2) may include a module level power electronics (MLPE) device.

[0123] The MLPE device controls power conversion on a per-solar module basis and can optimize generated energy by including an optimizer. The MLPE device may include a monitoring function that monitors the status or power generation of the photovoltaic module and transmits data externally.

[0124] Additionally, the MLPE device includes a Rapid Shutdown (RSD) function, which can stop the operation of the photovoltaic module depending on the severity of the failure.

[0125] The photovoltaic module (2) may include a monitoring device that monitors the status or power generation amount of the photovoltaic module (PhotoVoltaic Module) or a rapid shutdown device (RSD) that performs a rapid shutdown function.

[0126] Additionally, at least one of the plurality of solar modules and MLPE devices may include a communication module for power line communication.

[0127]

[0128] The description of this specification above is for illustrative purposes only, and those skilled in the art will readily appreciate that the contents of this specification can be easily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0129] Unless the steps constituting the method according to the present invention are explicitly described in a specific order or are otherwise described in a different order, the steps may be performed in any appropriate order. The present invention is not necessarily limited to the order in which the steps are described. The use of all examples or exemplary terms (e.g., “for example,” “etc.”) in the present invention is merely intended to illustrate the present invention in detail, and the scope of the present invention is not limited by the examples or exemplary terms unless otherwise defined by the claims. Furthermore, those skilled in the art will appreciate that various modifications, combinations, and variations can be configured according to design conditions and factors within the scope of the appended claims or their equivalents.

[0130] Therefore, the idea of ​​the present invention should not be limited to the embodiments described above, and not only the scope of the patent claims described below but also all scopes equivalent to or equivalently modified from the scope of the patent claims are considered to fall within the scope of the idea of ​​the present invention.

Claims

1. A switching element installed between each solar string and the inverter, and connecting or insulating each solar string and the inverter based on a control signal; and A comparator that outputs the control signal based on the result of comparing the voltage at the front end and the voltage at the rear end of the switching element; MLPE device for preventing damage to solar modules, including:

2. In paragraph 1, The above MLPE device, An isolated converter that generates and outputs an isolated voltage; MLPE device for preventing damage to solar modules, including:

3. In paragraph 2, The above MLPE device, An overvoltage protection circuit that applies the voltage generated from each solar string to the insulated converter based on whether the voltage generated from each solar string is overvoltage; MLPE device for preventing damage to solar modules, including:

4. In paragraph 2, The above comparator is, An MLPE device for preventing damage to a solar module, characterized in that it is driven by receiving an insulated voltage output from the above-mentioned insulated converter.

5. In paragraph 1, The above comparator is, An MLPE device for preventing damage to a solar module, characterized in that it outputs the control signal for turning off the switching element when the voltage of the front end of the switching element is lower than the voltage of the rear end, and outputs the control signal for turning on the switching element when the voltage of the front end of the switching element is higher than the voltage of the rear end.

6. In paragraph 5, The above switching element, An MLPE device for preventing damage to a solar module, characterized in that each solar string and the inverter are insulated based on the off control signal, and each solar string and the inverter are connected based on the on control signal.

7. A step of detecting the voltage at the front end and the voltage at the rear end of the switching element; and A step of controlling the switching element based on a comparison result between the voltage at the front end of the switching element and the voltage at the rear end; A method for controlling an MLPE device for preventing damage to a solar module, including:

8. In paragraph 7, The above detection step is, A step of forming a plurality of solar strings by connecting a plurality of solar modules in series; and A step of applying a voltage generated from each solar string to the switching element; A method comprising:

9. In paragraph 7, The above controlling step is, A step of turning off the switching element so that each solar string and the inverter are insulated when the voltage at the front end of the switching element is lower than the voltage at the rear end, and turning on the switching element so that each solar string and the inverter are connected when the voltage at the front end of the switching element is higher than the voltage at the rear end; A method comprising:

10. In paragraph 8, The above controlling step is, A step of generating an isolated voltage based on whether the voltage generated from each of the solar strings is overvoltage, and applying the isolated voltage to a comparator to compare the voltage at the front end and the voltage at the rear end of the switching element; A method comprising:

11. A switching element installed between each solar string and the inverter, and connecting or insulating each solar string and the inverter based on a control signal; and A comparator that outputs the control signal based on the result of comparing the voltage at the front end and the voltage at the rear end of the switching element; An electronic circuit for preventing damage to a solar module, including:

12. In paragraph 11, The electronic circuit to prevent damage to the above solar module is: An isolated converter that generates and outputs an isolated voltage; An electronic circuit for preventing damage to a solar module, including:

13. In paragraph 12, The electronic circuit to prevent damage to the above solar module is: An overvoltage protection circuit that applies the voltage generated from each solar string to the insulated converter based on whether the voltage generated from each solar string is overvoltage; An electronic circuit for preventing damage to a solar module, including:

14. In paragraph 12, The above comparator is, An electronic circuit for preventing damage to a solar module, characterized in that it is driven by receiving an isolated voltage output from the above-mentioned insulated converter.

15. In paragraph 11, The above comparator is, An electronic circuit for preventing damage to a solar module, characterized in that it outputs the control signal for turning off the switching element when the voltage of the front end of the switching element is lower than the voltage of the rear end, and outputs the control signal for turning on the switching element when the voltage of the front end of the switching element is higher than the voltage of the rear end.

16. In paragraph 15, The above switching element, An electronic circuit for preventing damage to a solar module, characterized in that each solar string and the inverter are insulated based on the off control signal, and each solar string and the inverter are connected based on the on control signal.

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