Inverter and main controller of solar power generation system, and operation method of solar system

Abstract

Disclosed are an inverter and a main controller of a solar power generation system, and an operation method of a solar system. An operation method of a solar power generation system is performed by a main controller of the solar power generation system, and may comprise the steps of: generating a plurality of operation signals having different signal strengths; periodically transmitting the plurality of operation signals to a plurality of module level power electronics (MLPEs) connected to a plurality of solar panels; and receiving, from at least one of the MLPEs which received at least one operation signal among the plurality of operation signals that are periodically transmitted, response signals to the operation signals; and controlling the strengths of the plurality of operation signals on the basis of the result of receiving the response signals.

Description

Inverter and main controller of a photovoltaic power generation system, and method of operation of a photovoltaic system

[0001] The present invention relates to a technology that enables each MLPE in a photovoltaic power generation system to receive operation signals normally regardless of the surrounding environment by transmitting a plurality of operation signals with different signal strengths from a main controller in the photovoltaic power generation system.

[0002] A photovoltaic power generation system may include a module-level power converter (or module-level power regulator) (Module Level Power Electronics, hereinafter referred to as 'MLPE') and a main controller attached to a photovoltaic panel.

[0003] The MLPE periodically receives an operation signal (e.g., a Heart Beat signal) from the main controller and can perform power generation of the solar panel upon receiving the operation signal. This MLPE transmits power generation information, including the amount of power generated, temperature, and fault information of the solar panel, to the main controller, thereby enabling the status of power generation to be determined.

[0004] If the MLPE does not receive an operation signal from the main controller, it may stop power generation, which could prevent the solar panels from operating normally. Consequently, the main controller may unnecessarily detect an abnormality and perform a Rapid Shutdown (RSD) of the solar power generation system, which could lead to a decrease in power generation efficiency.

[0005] Therefore, it is important that the operation signal is transmitted normally to the MLPE. However, due to reasons such as the distance between the main controller and the MLPE, and impedance differences caused by component variations, the reception sensitivity of the MLPE to the operation signal transmitted from the main controller may decrease. Consequently, it may become difficult for the MLPE to receive the operation signal normally.

[0006] The objective of the present invention is to provide a photovoltaic power generation system that transmits a plurality of operation signals with different signal strengths from a main controller to an MLPE, thereby ensuring that the operation signals are received normally at the MLPE even when the reception sensitivity of the operation signals transmitted from the main controller is reduced due to the distance between the main controller and the MLPE and the impedance difference caused by component deviation.

[0007] The objective of the present invention is to determine an MLPE that has not sent a response signal to an operation signal among a plurality of MLPEs during a set error determination time as an error state, and to generate and output an error state message for the MLPE that has not sent a response signal, thereby enabling accurate and rapid identification and processing of the error state of the MLPE.

[0008] According to one embodiment of the present invention, a method of operation of a photovoltaic power generation system is a method of operation performed by a main controller of a photovoltaic power generation system, and may include the steps of generating a plurality of operation signals having different signal strengths, periodically transmitting a plurality of operation signals to a plurality of MLPEs (Module Level Power Electronics) connected to a plurality of photovoltaic panels, receiving a response signal for an operation signal from at least one MLPE that has received at least one operation signal among the plurality of operation signals transmitted periodically, and controlling the strength of the plurality of operation signals based on the result of receiving the response signal.

[0009] In the present invention, the step of controlling the strength of a plurality of operation signals may include: a step of accumulating and counting the number of responses to the operation signal for each of the plurality of MLPEs as a response signal is received from at least one MLPE during a set observation time; and a step of fixing the strength of the operation signal received by any MLPE if there is any MLPE whose number of responses is greater than or equal to a set threshold.

[0010] In the present invention, the step of controlling the strength of a plurality of operation signals may further include the step of changing the strength of the remaining operation signals, excluding the operation signal received by any MLPE among the plurality of operation signals.

[0011] In the present invention, the step of generating a plurality of operation signals may include the step of generating a plurality of operation signals with different signal strengths based on the distance between a plurality of MLPEs and a main controller.

[0012] In the present invention, the method of operating a photovoltaic power generation system may further include the step of determining an MLPE that has not sent a response signal during a set error determination time as an error state, and generating and outputting an error state message for the MLPE that has not sent a response signal.

[0013] In the present invention, the step of controlling the strength of a plurality of operation signals may include changing the strength of some of the operation signals by adjusting the amplification rate for the operation signals using a digital variable resistor of an amplifier that amplifies the operation signals, changing the strength of some of the operation signals through transistor control of the amplifier, or changing the strength of some of the operation signals using a voltage control converter.

[0014] According to one embodiment of the present invention, a main controller of a photovoltaic power generation system may include a generating unit that generates a plurality of operation signals with different signal strengths, a communication unit that periodically transmits a plurality of operation signals to a plurality of Module Level Power Electronics (MLPEs) connected to a plurality of photovoltaic panels and receives a response signal for the operation signal from at least one MLPE that receives at least one operation signal among the plurality of operation signals transmitted periodically, and a signal control unit that controls the strength of the plurality of operation signals based on the result of receiving the response signal.

[0015] In the present invention, the signal control unit receives a response signal from at least one MLPE during a set observation time, accumulates and counts the number of responses to an operation signal for each of the plurality of MLPEs, and if there is any MLPE whose number of responses is greater than or equal to a set threshold, the strength of the operation signal received by any MLPE can be fixed.

[0016] In the present invention, the signal control unit can change the strength of the remaining operation signals, excluding the operation signal received by any MLPE among a plurality of operation signals.

[0017] In the present invention, the generating unit can generate a plurality of operation signals with different signal strengths based on the distance between a plurality of MLPEs and a main controller.

[0018] In the present invention, the signal control unit determines an MLPE that has not sent a response signal during a set error determination time to be in an error state, and can generate and output an error state message for the MLPE that has not sent a response signal.

[0019] In the present invention, the signal control unit can change the strength of some of the operation signals by adjusting the amplification rate of the operation signal using a digital variable resistor of an amplifier that amplifies the operation signal, change the strength of some of the operation signals through transistor control of the amplifier, or change the strength of some of the operation signals using a voltage control converter.

[0020] According to one embodiment of the present invention, an inverter of a photovoltaic power generation system comprises a processor and a memory that is operablely connected to the processor and stores at least one code executed by the processor. The processor generates a plurality of operation signals with different signal strengths, periodically transmits a plurality of operation signals to a plurality of Module Level Power Electronics (MLPEs) connected to a plurality of photovoltaic panels, receives a response signal for the operation signal from at least one MLPE that receives at least one operation signal among the plurality of operation signals transmitted periodically, and can control the strength of the plurality of operation signals based on the result of receiving the response signal.

[0021] In the present invention, the processor receives a response signal from at least one MLPE during a set observation time, accumulates and counts the number of responses to an operation signal for each of the plurality of MLPEs, and if any MLPE exists in which the number of responses is greater than or equal to a set threshold, the strength of the operation signal received by any MLPE can be fixed.

[0022] In the present invention, the processor can change the strength of the remaining operation signals, excluding the operation signal received by any MLPE among a plurality of operation signals.

[0023] In the present invention, the processor can generate a plurality of operation signals with different signal strengths based on the distance between a plurality of MLPEs and an inverter.

[0024] In the present invention, the processor determines an MLPE that has not sent a response signal during a set error determination time to be in an error state, and can generate and output an error state message for the MLPE that has not sent a response signal.

[0025] In the present invention, the processor may change the strength of some of the operation signals by adjusting the amplification rate for the operation signal using a digital variable resistor of an amplifier that amplifies the operation signal, change the strength of some of the operation signals through transistor control of the amplifier, or change the strength of some of the operation signals using a voltage control converter.

[0026] The main controller can transmit multiple operation signals with different signal strengths to the MLPE. Accordingly, even if the reception sensitivity of the MLPE for the operation signal transmitted from the main controller decreases due to the distance between the main controller and the MLPE or impedance differences caused by component deviations, the operation signal can be received normally at the MLPE.

[0027] During the set error determination time, an MLPE that has not sent a response signal to an operation signal among a plurality of MLPEs is determined to be in an error state, and an error state message for the MLPE that has not sent a response signal can be generated and output. Accordingly, the error state of the MLPE can be accurately and quickly identified and processed. Therefore, the photovoltaic power generation system can increase power generation efficiency by minimizing rapid shutdown operations.

[0028] FIG. 1 is a configuration diagram illustrating a photovoltaic power generation system according to one embodiment.

[0029] FIG. 2 is a configuration diagram illustrating a photovoltaic power generation system according to another embodiment.

[0030] FIG. 3 is a configuration diagram illustrating an example of a main controller included in a photovoltaic power generation system according to one embodiment.

[0031] FIG. 4 is a flowchart illustrating an example of a method of operation for a photovoltaic power generation system according to one embodiment.

[0032] FIG. 5 is a flowchart illustrating an example of determining an error state among the operation methods of a photovoltaic power generation system according to one embodiment.

[0033] FIG. 6 is a data flow diagram illustrating another example of a method of operation for a photovoltaic power generation system according to one embodiment.

[0034] FIGS. 7 and 8 are drawings for illustrating examples of controlling the intensity of a plurality of operation signals in a photovoltaic power generation system according to one embodiment.

[0035] FIG. 9 is a drawing for explaining the power supply structure of a building in which a solar panel of a photovoltaic power generation system according to one embodiment is installed.

[0036] FIG. 10 is a diagram illustrating a plurality of operation signals according to one embodiment.

[0037] A method of operation for a photovoltaic power generation system is a method of operation performed by a main controller of the photovoltaic power generation system, and may include the steps of generating a plurality of operation signals having different signal strengths, periodically transmitting a plurality of operation signals to a plurality of MLPEs (Module Level Power Electronics) connected to a plurality of photovoltaic panels, receiving a response signal for an operation signal from at least one MLPE that has received at least one operation signal among the plurality of operation signals transmitted periodically, and controlling the strength of the plurality of operation signals based on the result of receiving the response signal.

[0038] The terms used in the embodiments have been selected to be as close as possible to currently widely used general terms; however, these may vary depending on the intent of those skilled in the art, case law, the emergence of new technologies, etc. Additionally, in specific cases, terms have been selected at the applicant's discretion, and in such cases, their meanings will be described in detail in the relevant description section. Therefore, terms used in the specification must be defined not merely by their names, but based on their meanings and the content throughout the specification.

[0039] When a part of a specification is described as “comprising” a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0040] Additionally, terms including ordinal numbers, such as “first” or “second” used in the specification, may be used to describe various components, but said components should not be limited by said terms. said terms may be used for the purpose of distinguishing one component from another.

[0041] The embodiments are described in detail below with reference to the attached drawings. However, the embodiments may be implemented in various different forms and are not limited to the examples described herein.

[0042] FIG. 1 is a configuration diagram illustrating an example of a photovoltaic power generation system according to one embodiment. FIG. 2 is a configuration diagram illustrating a photovoltaic power generation system according to another embodiment.

[0043] Referring to FIG. 1, a photovoltaic power generation system (1) may include a plurality of photovoltaic panels (10), an inverter (400) including a primary controller (100), a plurality of MLPEs (200), and a server (300). Alternatively, the photovoltaic power generation system (1) may be configured to include a plurality of photovoltaic panels (10), a primary controller (100), a plurality of MLPEs (200), an inverter (400), and a server (300). For example, the primary controller (100) may include a Power Line Communication Control Board.

[0044] For example, the inverter (400) may include a main controller (100). Alternatively, the inverter (400) may be positioned between the main controller (100) and a grid (not shown). Here, the inverter (400) may convert direct current power generated from a plurality of solar panels (10) into alternating current power and transmit the converted alternating current power to the grid.

[0045] For example, a plurality of solar panels (10) may be connected in at least one of series and parallel. Additionally, one MLPE (200) may be connected to one solar panel (10), or one MLPE (200) may be connected to a plurality of solar panels (10).

[0046] Each MLPE (200: 201, 202, 203) is connected to a solar panel (10) one-to-one and can perform power generation of each connected solar panel (10) based on an operation signal received from the main controller (100). Each MLPE (200: 201, 202, 203) transmits power generation information, including the amount of power generated, temperature, and fault information of the solar panel (10), to the main controller (100) so that the power generation status can be determined.

[0047] These multiple MLPEs (200) can periodically (at set times) receive at least one operation signal among multiple operation signals with different signal strengths from the main controller (100), and generate a response signal for the received operation signal and transmit it to the main controller (100). For example, the operation signal may include a heartbeat signal.

[0048] Multiple MLPEs (200) can also transmit their own unique information (e.g., serial number) along with the response signal so that the main controller (100) can identify the MLPE that transmitted the response signal.

[0049] At this time, the MLPE (200) can be connected to the solar panel (10) in a one-to-one correspondence as shown in FIG. 1, but can be installed in a many-to-one or many-to-many manner depending on the structure adopted by the solar power generation system (1), and the installation form is not limited to any one.

[0050] MLPEs (200) are provided in multiple numbers and connected in series with each other, and an inverter (400) or a main controller (100) may be connected to both ends of the series-connected multiple MLPEs (200). Alternatively, as shown in FIG. 2, a main controller (100) (or an inverter) may be connected to one end of a plurality of MLPEs (200) including the first to nth (n is a natural number greater than or equal to 2) MLPEs.

[0051] The inverter (400) is a component installed in the PCS (Power Conversion System) that performs power conversion to supply power produced from the solar panel (10) to a load or grid.

[0052] The inverter (400) can identify the maximum power point voltage by performing a Maximum Power Point Tracking (hereinafter referred to as 'MPPT') operation to track the corresponding power and voltage when the photovoltaic power generation system (1) generates maximum power. The MPPT operation is an algorithm implemented to continuously adjust the impedance received by a photovoltaic panel (10) or an array composed of multiple photovoltaic panels (10) so that the photovoltaic power generation system (1) operates near the maximum power point when conditions such as solar irradiance, temperature, and load change.

[0053] The inverter (400) controls the MLPE (200) to perform MPPT operation and can maximize the power production efficiency of the photovoltaic power generation system (1). In addition, the inverter (400) can monitor the operating status by analyzing various data received from the photovoltaic panel (10), MLPE (200), load, grid, etc.

[0054] The main controller (100) can generate multiple operation signals with different signal strengths and periodically transmit multiple operation signals to multiple MLPEs (200) connected to multiple solar panels (10). For example, referring to FIG. 2, a first MLPE (201) located at the shortest distance from the main controller (100) can receive multiple operation signals from the main controller (100) and transmit them to a second MLPE (202), and the second MLPE (202) can receive multiple operation signals from the first MLPE (201) and transmit them to a third MLPE (not shown).

[0055] Here, the nth MLPE (203) located at the longest distance from the main controller (100) can receive an operation signal transmitted from the main controller (100) via the first MLPE (201) to the n-1st MLPE (not shown). At this time, the nth MLPE (203) receives the operation signal via multiple MLPEs, and even if the reception sensitivity for the operation signal transmitted from the main controller (100) is reduced due to the distance between the nth MLPE (203) and the main controller (100) and the impedance difference due to component deviation between the multiple MLPEs, multiple operation signals with different signal strengths can be transmitted from the main controller (100). Accordingly, at least one operation signal among the multiple operation signals can be accurately received. Upon receiving at least one operation signal, each MLPE can generate a response signal for the operation signal and transmit it to the main controller (100).

[0056] The main controller (100) receives a response signal for the operation signal from at least one MLPE that receives at least one operation signal among a plurality of operation signals transmitted periodically, and can control the intensity of the plurality of operation signals based on the result of receiving the response signal.

[0057] The main controller (100) collects and outputs the results of receiving response signals received from multiple MLPEs (200) or transmits them to a server (300) (or an administrator terminal), thereby enabling the administrator to recognize the status of multiple MLPEs (200). Here, the transmission and reception of information between the main controller (100) and the server (300) can be performed via a wired or wireless method.

[0058] Information transmission and reception between multiple MLPEs (200) and a main controller (100) can be performed using Power Line Communication (PLC). When using Power Line Communication, it is not necessary to use separate communication cables or wireless communication technology for information transmission and reception between multiple MLPEs (200) and a main controller (100), so installation and maintenance of the photovoltaic power generation system (1) can be made easier.

[0059] FIG. 3 is a configuration diagram illustrating an example of a main controller included in a photovoltaic power generation system according to one embodiment.

[0060] Referring to FIGS. 1 to 3, the main controller (100) (or inverter) may be configured to include a processor (110) and a memory (120). Here, the processor (110) may be configured to include a generation unit (111), a communication unit (112), and a signal control unit (113). However, each of the above-described units is merely a functional configuration for explaining the operation of the processor (110), and the operation of the present invention is not limited by the distinction of each unit.

[0061] The generating unit (111) can generate multiple operation signals with different signal strengths. At this time, the generating unit (111) can generate multiple operation signals with different signal strengths based on the distance between the multiple MLPEs (200) and the main controller (100) (or inverter).

[0062] The generating unit (111) can generate one operation signal corresponding to the strength of a set signal, and by changing the strength of the generated operation signal based on at least one of a set adjustment value, the distance between a plurality of MLPEs (200) and a main controller (100) (or inverter), and the separation distance between a plurality of MLPEs (200), a plurality of operation signals with different signal strengths can be generated. The distance between a plurality of MLPEs (200) and a main controller (100) and the separation distance between a plurality of MLPEs (200) may be pre-set or received from a server (300) (or an administrator terminal, not shown).

[0063] The communication unit (112) can communicate with a plurality of MLPEs (200) connected to a plurality of solar panels (10) or with a server (300) (or a manager terminal).

[0064] The communication unit (112) periodically transmits a plurality of operation signals to a plurality of MLPEs (200) (e.g., at set intervals) and can receive a response signal for the operation signal from at least one MLPE that has received at least one operation signal among the plurality of operation signals transmitted periodically. In an embodiment, the communication unit (112) can, for example, transmit first to fifth operation signals with different signal strengths to a plurality of MLPEs (200) in sequence, and can transmit the first to fifth operation signals every 5 seconds. At this time, after transmitting the first operation signal, the communication unit (112) can receive the unique information of the MLPE along with the response signal for the first operation signal from at least one MLPE among the plurality of MLPEs (200), and after transmitting the second operation signal, can receive the unique information of the MLPE along with the response signal for the second operation signal from at least one MLPE among the plurality of MLPEs (200).

[0065] Alternatively, the communication unit (112) may collectively transmit first to fifth operation signals, each with a different signal strength, to a plurality of MLPEs (200) every 5 seconds. At this time, after transmitting the first to fifth operation signals, the communication unit (112) may receive a response signal for at least one operation signal from at least one of the plurality of MLPEs (200), along with the unique information of the MLPE and the strength of the operation signal received by the MLPE.

[0066] The signal control unit (113) controls the strength of a plurality of operation signals generated by the generation unit (111) based on the reception result of response signals from a plurality of MLPEs (200), and by changing the strength of the operation signals according to the environment, the operation signals can be received normally by the plurality of MLPEs (200) even if a decrease in reception sensitivity of the operation signals in the MLPEs occurs.

[0067] The signal control unit (113) can accumulate and count the number of responses to operation signals for each of the plurality of MLPEs by receiving a response signal from at least one MLPE through the communication unit (112), and store the counted number of responses in the memory (120). As the set observation time elapses, the signal control unit (113) can check the number of responses accumulated and counted for operation signals for each of the plurality of MLPEs in the memory (120).

[0068] The signal control unit (113) can fix the strength of the operation signal received by any MLPE if, during a set observation time, there exists any MLPE whose number of responses to the operation signal is greater than or equal to a set threshold. At this time, the signal control unit (113) can change the strength of the remaining operation signals among the plurality of operation signals, excluding the operation signal received by any MLPE.

[0069] The signal control unit (113) can change the strength of some of the operation signals (for example, the remaining operation signals excluding the operation signal received by any MLPE whose response count is greater than or equal to a set threshold among the operation signals) by adjusting the amplification rate of the operation signal using a digital variable resistor of the amplifier unit that amplifies the operation signal generated by the generation unit (111), or change the strength of some of the operation signals through transistor control of the amplifier unit, or change the strength of some of the operation signals using a voltage control converter.

[0070] Additionally, the signal control unit (113) determines that an MLPE that has not sent a response signal to an operation signal during a set error determination time is in an error state, and generates and outputs an error state message for the MLPE that has not sent a response signal, or transmits it to the server (300) (or administrator terminal), thereby enabling the administrator to accurately and quickly identify and process the error state of the MLPE.

[0071] The processor (110) may be implemented as an array of multiple logic gates, or as a combination of a general-purpose microprocessor and memory storing a program that can be executed on the microprocessor. For example, the processor (110) may include a general-purpose processor, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a controller, a microcontroller, a state machine, etc. In some environments, the processor (110) may include an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), etc. For example, the processor (110) may refer to a combination of processing devices such as a combination of a digital signal processor (DSP) and a microprocessor, a combination of multiple microprocessors, a combination of one or more microprocessors combined with a digital signal processor (DSP) core, or any other combination of such configurations.

[0072] The memory (120) is hardware that stores various data processed within the main controller (100), is operably connected to the processor (110), and can store a program for processing and controlling the processor (110).

[0073] The memory (120) may include RAM (random access memory), such as DRAM (dynamic random access memory) and SRAM (static random access memory), ROM (read-only memory), EEPROM (electrically erasable programmable read-only memory), CD-ROM, Blu-ray or other optical disc storage, HDD (hard disk drive), SSD (solid state drive), or flash memory.

[0074] FIG. 4 is a flowchart illustrating an example of a method of operation for a photovoltaic power generation system according to one embodiment.

[0075] For example, the operation method of the photovoltaic power generation system illustrated in FIG. 4 can be performed by a main controller (or inverter).

[0076] Referring to FIG. 4, in step S110, the main controller can generate a plurality of operation signals with different signal strengths. The main controller can generate one operation signal corresponding to a set signal strength, and generate a plurality of operation signals with different signal strengths by changing the strength of the generated operation signal based on at least one of a set adjustment value, a distance between a plurality of MLPEs and the main controller (or inverter) (e.g., the distance between the first MLPE and the main controller, the distance between the second MLPE and the main controller in FIG. 2, etc.), and a separation distance between a plurality of MLPEs (e.g., the distance between the first MLPE and the second MLPE in FIG. 2, the distance between the n-1 MLPE and the n MLPE).

[0077] Hereinafter, examples of multiple operation signals generated by the main controller will be explained with reference to FIG. 10.

[0078] FIG. 10 is a diagram illustrating a plurality of operation signals according to one embodiment.

[0079] Referring to FIG. 10(a), the operation signals according to the prior art all have the same signal strength and are transmitted through a single stage. Meanwhile, referring to FIG. 10(b), the operation signals according to one embodiment are transmitted through a plurality of stages (n stage, n+a stage, n+b stage) as multiple signals of different strengths. Therefore, even if the MLPE receives only one of the multiple operation signals having different strengths, the MLPE and the main controller can communicate normally.

[0080] Accordingly, even if the reception sensitivity for an operation signal transmitted from the main controller is reduced due to the distance between the nth MLPE and the main controller and the impedance difference caused by component deviations between multiple MLPEs, multiple operation signals with different signal strengths can be transmitted from the main controller. Accordingly, each MLPE can accurately receive at least one operation signal among the multiple operation signals.

[0081] Referring again to FIG. 4, in step S120, the main controller may periodically transmit a plurality of operation signals to a plurality of MLPEs connected to a plurality of solar panels. For example, the main controller may transmit first to fifth operation signals with different signal strengths in sequence every 5 seconds, or transmit them collectively.

[0082] In step S130, the main controller may receive a response signal for an operation signal from at least one MLPE that has received at least one operation signal among a plurality of operation signals transmitted periodically. For example, when the main controller transmits first to fifth operation signals with different signal strengths in sequence to first to ten MLPEs, after transmitting the first operation signal, it may receive unique information of the MLPE along with a response signal for the first operation signal from at least one MLPE among the first to ten MLPEs, and after transmitting the second operation signal, it may receive unique information of the MLPE along with a response signal for the second operation signal from at least one MLPE among the first to ten MLPEs.

[0083] For example, when the main controller transmits first to fifth operation signals with different signal strengths to first to ten MLPEs in batches, after transmitting the first to fifth operation signals, it can receive unique information of the MLPE and the strength of the operation signal received by the MLPE, along with a response signal for at least one operation signal from at least one of the first to ten MLPEs.

[0084] As the main controller receives a response signal from at least one MLPE during a set observation time (e.g., 60 seconds), it can accumulate and count the number of responses to an operation signal for each of the multiple MLPEs based on the unique information of the MLPE received along with the response signal, and store the counted number of responses in memory. The main controller may accumulate and count the number of responses based on the response signal to the operation signal received from the MLPE, but is not limited thereto. For example, the number of receptions in which the number of receptions to the operation signal is accumulated and counted by the MLPE can be received from the MLPE as the number of responses to the operation signal, and a detailed explanation thereof will be described later with reference to FIG. 6.

[0085] In step S140, the main controller can determine whether the number of responses for a plurality of MLPEs is all greater than or equal to a set threshold. At this time, the main controller can detect the number of responses for operation signals for each of the plurality of MLPEs from memory and determine whether the number of responses for operation signals in the plurality of MLPEs is all greater than or equal to a set threshold.

[0086] Based on the judgment result of step S140, if the main controller determines that the number of responses to operation signals from multiple MLPEs is all above a set threshold, it determines that operation signals have been received normally from all MLPEs. Accordingly, in step S170, the main controller can fix the strength of multiple operation signals that are periodically transmitted. For example, if the multiple MLPEs include the first to tenth MLPEs, the main controller can fix the strength of the first to fifth operation signals if the number of responses regarding the first MLPE to the tenth MLPE is each determined to be above a set threshold.

[0087] If, as a result of the judgment in step S140, the main controller determines that the number of responses to operation signals in multiple MLPEs is not all greater than or equal to a set threshold, then in step S150, the main controller can determine whether there exists any MLPE whose number of responses is greater than or equal to a set threshold.

[0088] If, as a result of the judgment in step S150, the main controller determines that there is no arbitrary MLPE whose response count is greater than or equal to a set threshold, then in step S151, the main controller may change the strength of a plurality of operation signals. The main controller transmits a plurality of operation signals with changed signal strengths, and receives a response signal for the operation signal from at least one MLPE that has received at least one of the plurality of operation signals, thereby accumulating and counting the number of responses to the operation signal for each of the plurality of MLPEs. Afterward, the main controller may proceed to step S140.

[0089] If, as a result of the determination in step S150, the main controller determines that there exists an arbitrary MLPE whose response count is greater than or equal to a set threshold, in step S160, the main controller may fix the strength of the operation signal received by the arbitrary MLPE. Subsequently, in step S161, the main controller changes the strength of the remaining operation signals among the plurality of operation signals, excluding the operation signal received by the arbitrary MLPE. Then, the main controller transmits a plurality of operation signals including the operation signal with the changed strength and the fixed operation signal. Then, as the main controller receives a response signal for the operation signal from at least one MLPE that received at least one of the plurality of operation signals, the main controller may accumulate and count the number of responses to the operation signal for each of the plurality of MLPEs. Subsequently, the main controller may proceed to step S140. For example, the main controller transmits the first to fifth operation signals to the first to tenth MLPEs, and when the threshold value is '8', if the number of responses to the first operation signal at the first MLPE among the first to tenth MLPEs is '10', the strength of the first operation signal received at the first MLPE can be fixed because the number of responses to the first operation signal at the first MLPE is greater than or equal to the threshold value. On the other hand, the main controller can change the strength of the second to fifth operation signals excluding the first operation signal. At this time, the main controller can change the strength of the second to fifth operation signals based on at least one of the distance between the MLPE (second MLPE to tenth MLPE) and the main controller and the distance between the MLPEs (second MLPE to tenth MLPE). For example, the main controller can change the strength of the second to fifth operation signals to be higher as the distance between the MLPE and the main controller or the distance between the MLPEs increases.

[0090] When changing the strength of the operation signal, the main controller may change the strength of the operation signal by adjusting the amplification rate of the operation signal using a digital variable resistor of the amplifier that amplifies the operation signal, change the strength of the operation signal by controlling the transistor of the amplifier, or change the strength of the operation signal using a voltage control converter, and a detailed explanation thereof will be provided later with reference to FIGS. 7 and 8.

[0091] The main controller adaptively controls the strength of multiple operation signals based on the reception results regarding response signals from multiple MLPEs, thereby enabling normal reception of operation signals from multiple MLPEs regardless of the surrounding environment.

[0092] FIG. 5 is a flowchart illustrating an example of determining an error state among the operation methods of a photovoltaic power generation system according to one embodiment.

[0093] Referring to FIG. 5, in step S210, the main controller can control the strength of a plurality of operation signals based on the reception result regarding response signals from a plurality of MLPEs (see FIG. 4).

[0094] In step S220, the main controller determines whether an error judgment time (e.g., 3 minutes) set based on the time when a plurality of operation signals are first transmitted has elapsed, for example, and if it is determined that the error judgment time has not elapsed, it may proceed to step S210. Here, the error judgment time may be greater than the observation time (see S130 in FIG. 4).

[0095] If, as a result of the judgment in step S220, it is determined that the error judgment time has elapsed, in step S230, the main controller can determine whether there is an MLPE whose number of responses is less than a set threshold value.

[0096] If, as a result of the judgment in step S230, it is determined that there is an MLPE whose response count is less than a set threshold value, in step S240, the main controller generates and outputs an error status message for the MLPE that is less than the threshold value, or transmits it to a server (or administrator terminal), thereby enabling the error status of the MLPE to be recognized. That is, the main controller can determine that an MLPE that has not sent a response signal to an operation signal during a set error judgment time is in an error state, and by providing an error status message for the MLPE that has not sent a response signal to the server (or administrator terminal), the administrator can respond urgently without leaving the error status of the MLPE unattended.

[0097] FIG. 6 is a data flow diagram illustrating another example of a method of operation for a photovoltaic power generation system according to one embodiment.

[0098] Comparing the method illustrated in FIG. 4 with the method illustrated in FIG. 6, the method illustrated in FIG. 6 receives the number of responses to an operation signal from the MLPE instead of accumulating and counting the number of responses to an operation signal from the main controller. Except for the differences mentioned above, the remaining steps are identical in the method illustrated in FIG. 4 and the method illustrated in FIG. 6. Therefore, the description of the parts that are identical in the method illustrated in FIG. 4 and the method illustrated in FIG. 6 is omitted.

[0099] Referring to FIG. 6, the main controller (100) can generate a plurality of operation signals with different signal strengths and periodically transmit a plurality of operation signals to the MLPE (200) (steps S310, S320).

[0100] As at least one of a plurality of operation signals is received during a set observation time, the MLPE (200) can accumulate and count the number of times the operation signal is received (step S330). The MLPE (200) can transmit the number of times the operation signal is received, the strength of the received operation signal, and the unique information of the MLPE to the main controller (100).

[0101] The main controller (100) receives the number of times an operation signal is received from the MLPE (200) as the number of times a response is given to the operation signal, and can further receive the strength of the operation signal and the unique information of the MLPE (200) from the MLPE (200).

[0102] When the number of responses to an operation signal received from the MLPE (200) is greater than or equal to a set threshold, the main controller (100) can fix the strength of the operation signal received from the MLPE (200) among a plurality of operation signals that are periodically transmitted to the MLPE (200).

[0103] For example, the MLPE (200) may be configured to include a processor (not shown) and a memory (not shown). Here, when the processor receives at least one of a plurality of operation signals from the main controller (100), it may accumulate and count the number of times the received operation signal is received, and store the counted number of times the operation signal is received and the strength of the operation signal in the memory in correspondence with the unique information of the MLPE (200). Additionally, the processor may transmit the number of times the operation signal is received, the strength of the received operation signal, and the unique information of the MLPE to the main controller (100).

[0104] FIGS. 7 and 8 are drawings for illustrating examples of controlling the intensity of a plurality of operation signals in a photovoltaic power generation system according to one embodiment.

[0105] The main controller (or inverter) of a photovoltaic power generation system can control the strength of a plurality of operation signals based on the reception result regarding response signals from a plurality of MLPEs.

[0106] For example, the main controller can change the strength of the operation signal by changing the voltage at the MCU (Micro Controller Unit) ADC (Analog to Digital Converter) Out pin.

[0107] In an embodiment, the main controller can change the strength of the operating signal by adjusting the amplification rate of the signal transmitting amplifier (AMP). As shown in FIG. 7, the main controller uses the first resistor (R1) and the second resistor (R2) of the amplifier (e.g., a non-inverting amplifier) ​​as digital variable resistors to obtain an output value (V out By adjusting ), the strength of the operation signal is changed, or, as shown in FIG. 8, the transistor (TR, Q1) is turned ON / OFF to obtain an output value (V) as the combined resistance of the first resistor (R1) and the third resistor (R3). out By adjusting ), the strength of the operation signal can be changed.

[0108] For example, the main controller can change the strength of the operation signal using a buck converter or a boost converter. Alternatively, the main controller can change the strength of the operation signal by varying the VCC_12V power of the push-pull circuit, for example, using a buck converter or a boost converter.

[0109] FIG. 9 is a drawing for explaining the power supply structure of a building in which a solar panel of a photovoltaic power generation system according to one embodiment is installed.

[0110] Referring to Fig. 9, a solar panel (2) can be installed on the roof of a building to generate energy.

[0111] A solar inverter (6) (or main controller) can convert the energy of a solar panel (2) and supply generated power into a building (900).

[0112] Meanwhile, commercial power transmitted through the utility pole (3) can be supplied to the building through the transformer (4).

[0113] Multiple household appliances (7) can operate by selectively receiving at least one of the commercial power supply or the power generated by the solar panel (2). The power meter (5) can measure the amount of power consumed in the building (900).

[0114] In addition, if a separate energy storage system (ESS) is provided, the energy of the solar panel (2) can be stored in the energy storage system (ESS).

[0115] When multiple photovoltaic panels (2) are connected, a photovoltaic module string can be formed. A photovoltaic module string is a collection of multiple photovoltaic modules and may include one output terminal.

[0116] Meanwhile, the solar panel (2) may include or be connected to MLPE.

[0117] The solar panel (2) may include a monitoring device that monitors the condition or amount of power generated by the solar panel (2) or a rapid shutdown device (RSD) that performs a rapid shutdown function.

[0118] In addition, at least one of the plurality of solar panels and MLPEs may include a communication module for power line communication.

[0119] According to one embodiment of the present invention, by transmitting a plurality of operation signals with different signal strengths from a main controller to an MLPE, a photovoltaic power generation system can be provided that allows the operation signals to be received normally at the MLPE even when the reception sensitivity of the operation signals transmitted from the main controller is reduced due to the distance between the main controller and the MLPE and the impedance difference caused by component deviation.

[0120] In addition, according to one embodiment of the present invention, an MLPE that has not sent a response signal to an operation signal among a plurality of MLPEs during a set error determination time is determined to be in an error state, and an error state message for the MLPE that has not sent a response signal is generated and output, thereby enabling the error state of the MLPE to be accurately and quickly identified and processed.

Claims

1. A method of operation performed by a main controller of a photovoltaic power generation system, A step of generating multiple operation signals with different signal strengths; A step of periodically transmitting the plurality of operation signals to a plurality of MLPEs (Module Level Power Electronics) connected to a plurality of solar panels; and A method comprising the step of receiving a response signal for an operation signal from at least one MLPE that has received at least one operation signal among the plurality of operation signals transmitted periodically, and controlling the intensity of the plurality of operation signals based on the result of receiving the response signal. Operation method of a solar power generation system.

2. In Paragraph 1, The step of controlling the strength of the plurality of operation signals above is, A step of accumulating and counting the number of responses to an operation signal for each of the plurality of MLPEs as a result of receiving the response signal from the at least one MLPE during a set observation time; and If there exists an arbitrary MLPE whose response count is greater than or equal to a set threshold, the method includes the step of fixing the strength of the operation signal received by the arbitrary MLPE. Operation method of a solar power generation system.

3. In Paragraph 2, The step of controlling the strength of the plurality of operation signals above is, A method further comprising the step of changing the strength of the remaining operation signals, excluding the operation signal received by any MLPE among the plurality of operation signals. Operation method of a solar power generation system.

4. In Paragraph 1, The step of generating the above plurality of operation signals is, Based on the distance between the plurality of MLPEs and the main controller, the method comprises the step of generating a plurality of operation signals having different signal strengths. Operation method of a solar power generation system.

5. In Paragraph 1, The method further includes the step of determining an MLPE that has not sent the response signal during a set error determination time as being in an error state, and generating and outputting an error state message for the MLPE that has not sent the response signal. Operation method of a solar power generation system.

6. In Paragraph 1, The step of controlling the strength of the plurality of operation signals above is, A step comprising changing the strength of some of the operation signals among the plurality of operation signals by adjusting the amplification rate for the operation signal using a digital variable resistor of an amplifier that amplifies the operation signal, changing the strength of some of the operation signals through transistor control of the amplifier, or changing the strength of some of the operation signals using a voltage control converter. Operation method of a solar power generation system.

7. As a main controller of a solar power generation system, A generating unit that generates multiple operation signals with different signal strengths; A communication unit that periodically transmits the plurality of operation signals to a plurality of Module Level Power Electronics (MLPEs) connected to a plurality of solar panels, and receives a response signal for the operation signal from at least one MLPE that receives at least one operation signal among the plurality of operation signals transmitted periodically; and A signal control unit comprising a plurality of operation signals that controls the strength of the signal based on the reception result of the above response signal, The main controller of a solar power generation system.

8. In Paragraph 7, The above signal control unit is, Upon receiving the response signal during a set observation time, the number of responses to an operation signal for each of the plurality of MLPEs is accumulated and counted, and if there exists any MLPE whose number of responses is greater than or equal to a set threshold, the strength of the operation signal received by the any MLPE is fixed. The main controller of a solar power generation system.

9. In Paragraph 8, The above signal control unit is, Changing the strength of the remaining operation signals among the plurality of operation signals, excluding the operation signal received by any MLPE. The main controller of a solar power generation system.

10. In Paragraph 7, The above generating unit is, Based on the distance between the plurality of MLPEs and the main controller, a plurality of operation signals with different signal strengths are generated. The main controller of a solar power generation system.

11. In Paragraph 7, The above signal control unit is, Determining an MLPE that has not sent the response signal during a set error determination time as an error state, and generating and outputting an error state message for the MLPE that has not sent the response signal. The main controller of a solar power generation system.

12. In Paragraph 7, The above signal control unit is, By adjusting the amplification rate of the operation signal using a digital variable resistor of an amplifier that amplifies the operation signal, the strength of some of the operation signals among the plurality of operation signals is changed, or the strength of some of the operation signals is changed through transistor control of the amplifier, or the strength of some of the operation signals is changed using a voltage control converter. The main controller of a solar power generation system.

13. As an inverter for a solar power generation system, processor; and It includes a memory that is operablely connected to the processor and stores at least one code executed on the processor, The above processor is, Generating a plurality of operation signals with different signal strengths, periodically transmitting the plurality of operation signals to a plurality of Module Level Power Electronics (MLPEs) connected to a plurality of solar panels, receiving a response signal for the operation signal from at least one MLPE that has received at least one of the plurality of operation signals transmitted periodically, and controlling the strength of the plurality of operation signals based on the result of receiving the response signal. Inverter for a solar power generation system.

14. In Paragraph 13, The above processor is, Upon receiving the response signal from at least one MLPE during a set observation time, the number of responses to an operation signal for each of the plurality of MLPEs is accumulated and counted, and if any MLPE exists in which the number of responses is greater than or equal to a set threshold, the strength of the operation signal received by any MLPE is fixed. Inverter for a solar power generation system.

15. In Paragraph 14, The above processor is, Changing the strength of the remaining operation signals among the plurality of operation signals, excluding the operation signal received by any MLPE. Inverter for a solar power generation system.

16. In Paragraph 13, The above processor is, Based on the distance between the plurality of MLPEs and the inverter, a plurality of operation signals with different signal strengths are generated. Inverter for a solar power generation system.

17. In Paragraph 13, The above processor is, Determining an MLPE that has not sent the response signal during a set error determination time as an error state, and generating and outputting an error state message for the MLPE that has not sent the response signal. Inverter for a solar power generation system.

18. In Paragraph 13, The above processor is, By adjusting the amplification rate of the operation signal using a digital variable resistor of an amplifier that amplifies the operation signal, the strength of some of the operation signals among the plurality of operation signals is changed, or the strength of some of the operation signals is changed through transistor control of the amplifier, or the strength of some of the operation signals is changed using a voltage control converter. Inverter for a solar power generation system.

Images