Inverter and main controller of photovoltaic power generation system and operation method of the system

Abstract

An inverter and main controller for a photovoltaic (PV) power generation system, as well as a method for operating the system, are disclosed. The method for operating the PV power generation system is executed by the main controller and may include the following steps: generating multiple operating signals with different signal levels; periodically transmitting the multiple operating signals to multiple module-level power electronic devices (MLPEs) connected to multiple photovoltaic panels; and receiving response signals for the operating signals from at least one MLPE that has received at least one of the periodically transmitted operating signals, and controlling the signal levels of the multiple operating signals based on the reception result of the response signals.

Description

Technical Field

[0001] This disclosure relates to a technology that enables the main controller of a photovoltaic (PV) power generation system to send multiple operating signals with different signal levels, allowing each module-level power electronic device (MLPE) in the PV power generation system to correctly receive the operating signals regardless of the surrounding environment. Background Technology

[0002] A photovoltaic (PV) power generation system may include a module-level power electronic device (hereinafter referred to as MLPE) (or module-level power conversion device) and a main controller attached to the PV panel.

[0003] The MLPE can periodically receive operating signals (e.g., heartbeat signals) from the main controller and, in response to receiving these signals, execute power generation from the PV panels. This MLPE sends power generation information, including the PV panels' power output, temperature, and fault information, to the main controller, enabling the identification of the power generation status.

[0004] When no operating signal is received from the main controller, the MLPE may stop generating electricity, causing the PV panels to malfunction. Consequently, the main controller may unnecessarily detect the anomaly and execute a rapid shutdown (RSD) of the PV power generation system, leading to reduced power generation efficiency.

[0005] Therefore, it is important to correctly transmit the operation signal to the MLPE. However, due to factors such as the distance between the main controller and the MLPE, and impedance differences caused by component variations, the MLPE's sensitivity to receiving operation signals from the main controller deteriorates. Therefore, the MLPE may have difficulty correctly receiving the operation signal. Summary of the Invention

[0006] Technical goals

[0007] The purpose of this disclosure is to provide a photovoltaic (PV) power generation system in which a main controller sends multiple operating signals with different signal levels to a module-level power electronic device (MLPE), such that the MLPE can correctly receive the operating signals even if the MLPE's sensitivity to receiving the operating signals from the main controller is degraded due to the distance from the MLPE to the main controller and impedance differences caused by component variations.

[0008] The purpose of this disclosure is to identify an MLPE that has not sent a response signal to an operation signal during a preset time period for error determination, thereby identifying and displaying an error status message for the MLPE that has not sent a response signal, so that the error status of the MLPE can be accurately and quickly identified and responded to.

[0009] Technical solution

[0010] According to embodiments of this disclosure, an operation method for a photovoltaic (PV) power generation system may include: generating a plurality of operation signals with different signal levels; periodically transmitting the plurality of operation signals to a plurality of module-level power electronic devices (MLPEs) connected to a plurality of PV panels; and receiving a response signal for the operation signal from at least one MLPE that has received at least one of the periodically transmitted operation signals, and controlling the signal levels of the plurality of operation signals based on the reception result of the response signal.

[0011] In this disclosure, controlling the signal level of multiple operation signals may include: cumulatively counting the number of responses of each of the multiple MLPEs to the operation signal in response to receiving a response signal from at least one MLPE during a preset time period for observation; and fixing the signal level of the operation signal received by the corresponding MLPE in response to any MLPE having a number of responses equal to or greater than a preset threshold.

[0012] In this disclosure, controlling the signal level of multiple operation signals may further include: changing the signal level of the remaining operation signals among the multiple operation signals, excluding the operation signal received by the corresponding MLPE.

[0013] In this disclosure, generating multiple operation signals may include generating multiple operation signals with different signal levels based on the distance from multiple MLPEs to the main controller.

[0014] In this disclosure, the operating method may further include: determining that an MLPE that has not sent a response signal during a preset time period for error determination is in an error state, and generating and displaying an error state message about the MLPE that has not sent a response signal.

[0015] In this disclosure, controlling the signal level of multiple operating signals may include: changing the signal level of a portion of the multiple operating signals by adjusting the amplification rate of the operating signals using a digital variable resistor of an amplification unit for amplifying the operating signals, or changing the signal level of a portion of the multiple operating signals by controlling a transistor of the amplification unit, or changing the signal level of a portion of the multiple operating signals by using a voltage-controlled converter.

[0016] According to embodiments of this disclosure, the main controller of a photovoltaic (PV) power generation system may include: a generation unit configured to generate a plurality of operating signals with different signal levels; a communication unit configured to periodically transmit the plurality of operating signals to a plurality of module-level power electronic devices (MLPEs) connected to a plurality of photovoltaic (PV) panels, and to receive a response signal for the operating signal from at least one MLPE that has received at least one of the periodically transmitted operating signals; and a signal control unit configured to control the signal levels of the plurality of operating signals based on the reception result of the response signal.

[0017] In this disclosure, the signal control unit can, in response to receiving a response signal during a preset time period for observation, accumulate and count the number of responses of each of a plurality of MLPEs to the operation signal, and, in response to any MLPE having a number of responses equal to or greater than a preset threshold, fix the signal level of the operation signal received by the corresponding MLPE.

[0018] In this disclosure, the signal control unit can change the signal level of the remaining operating signals among a plurality of operating signals, excluding the operating signals received by any MLPE.

[0019] In this disclosure, the generation unit can generate multiple operating signals with different signal levels based on the distance from multiple MLPEs to the main controller.

[0020] In this disclosure, the signal control unit can determine that an MLPE that has not sent a response signal during a preset time period for error determination is in an error state, and generate and display an error state message about the MLPE that has not sent a response signal.

[0021] In this disclosure, the signal control unit can change the signal level of a portion of multiple operating signals by adjusting the amplification rate of the operating signal using a digital variable resistor of an amplification unit for amplifying the operating signal, or by controlling the transistor of the amplification unit, or by using a voltage control converter.

[0022] In embodiments of this disclosure, an inverter for a photovoltaic (PV) power generation system may include: a processor; and a memory operatively connected to the processor and configured to store at least one code executed by the processor, wherein the processor generates a plurality of operating signals with different signal levels, periodically sends the plurality of operating signals to a plurality of module-level power electronic devices (MLPEs) connected to a plurality of photovoltaic (PV) panels, receives response signals for the operating signals from at least one MLPE receiving at least one of the periodically sent operating signals, and controls the signal levels of the plurality of operating signals based on the reception of the response signals.

[0023] In this disclosure, the processor may, in response to receiving a response signal from at least one MLPE during a preset time period for observation, accumulate and count the number of responses of each of the plurality of MLPEs to the operation signal, and, in response to any MLPE having a number of responses equal to or greater than a preset threshold, fix the signal level of the operation signal received by the corresponding MLPE.

[0024] In this disclosure, the processor can change the signal level of the remaining operation signals among a plurality of operation signals, excluding the operation signal received by the corresponding MLPE.

[0025] In this disclosure, the processor can generate multiple operating signals with different signal levels based on the distance from multiple MLPEs to the inverter.

[0026] In this disclosure, the processor can determine that an MLPE that has not sent a response signal during a preset time period for error determination is in an error state, and generate and display an error state message about the MLPE that has not sent a response signal.

[0027] In this disclosure, the processor can change the signal level of a portion of multiple operating signals by adjusting the amplification rate of the operating signals using a digital variable resistor of an amplification unit for amplifying the operating signals, or by controlling the transistor of the amplification unit, or by using a voltage-controlled converter.

[0028] Invention Effects

[0029] The main controller can send multiple operating signals with different signal levels to the Module-Level Power Electronic Device (MLPE). Therefore, even if the MLPE's sensitivity to the operating signals sent from the main controller is degraded due to the distance between the MLPE and the main controller and impedance differences caused by component variations, the MLPE can still correctly receive the operating signals.

[0030] An MLPE that fails to send a response signal to the operation signal during a preset time period for error determination can be identified as being in an error state, and an error state message for the MLPE that failed to send a response signal can be generated and output. Therefore, error states of MLPEs can be accurately and quickly identified and responded to. Consequently, photovoltaic (PV) power generation systems can improve power generation efficiency by minimizing fast shutdown (RSD) operations. Attached Figure Description

[0031] Figure 1 A photovoltaic (PV) power generation system according to an embodiment is shown.

[0032] Figure 2 A PV power generation system according to another embodiment is shown.

[0033] Figure 3 This is a block diagram illustrating an example of a main controller included in a PV power generation system according to an embodiment.

[0034] Figure 4 This is a flowchart illustrating an example of an operation method of a PV power generation system according to an embodiment.

[0035] Figure 5 This is a flowchart illustrating an example of an error state in an operating method for a PV power generation system according to an embodiment.

[0036] Figure 6 This is a data flow diagram illustrating another example of the operation method of a PV power generation system according to an embodiment.

[0037] Figure 7 and Figure 8 This is a diagram illustrating an example of the signal levels of multiple operating signals in a PV power generation system according to an embodiment.

[0038] Figure 9 This is a diagram showing the power supply structure of a building with PV panels equipped with a PV power generation system according to an embodiment.

[0039] Figure 10 This is a diagram used to illustrate multiple operating signals according to an implementation method. Detailed Implementation

[0040] The operation method of a photovoltaic (PV) power generation system is an operation method executed by the main controller of the PV power generation system, and the operation method may include: generating multiple operation signals with different signal levels; periodically sending the multiple operation signals to multiple module-level power electronic devices (MLPEs) connected to multiple PV panels; and receiving a response signal for at least one operation signal from at least one MLPE that has received at least one of the periodically sent multiple operation signals, and controlling the signal levels of the multiple operation signals based on the reception result of the response signal.

[0041] Methods for implementing the present invention

[0042] The terminology used in this disclosure is selected from commonly used terms that are currently widely used in the art; however, these terms may be interpreted differently depending on the context, the intent of a person skilled in the art, or the emergence of new technologies. Additionally, in some cases, there are terms arbitrarily chosen by the applicant, in which case their meaning will be described in detail in the relevant sections of the specification. Therefore, the terms used in the specification should be defined based on their intended meaning and the overall context of the specification, and not merely on their names.

[0043] Throughout the specification, unless otherwise specifically stated otherwise, when a section “includes” a component, it means that it does not exclude other components, but may include other components.

[0044] Additionally, various constituent elements may be described using ordinal terms such as "first" or "second," but the constituent elements should not be limited by these terms. These terms may be used only for the purpose of distinguishing one constituent element from another.

[0045] Embodiments of this disclosure will be described in detail with reference to the accompanying drawings. However, embodiments may be implemented in different forms and are not limited to the examples set forth herein.

[0046] Figure 1 This is a block diagram illustrating an example of a photovoltaic (PV) power generation system according to an embodiment. Additionally, Figure 2 This is a block diagram illustrating a PV power generation system according to another embodiment.

[0047] Reference Figure 1 The PV power generation system 1 may include multiple PV panels 10, an inverter 400 including a main controller 100, multiple module-level power electronic devices (MLPEs) 200, and a server 300. Alternatively, the PV power generation system 1 may be configured to include multiple PV panels 10, a main controller 100, multiple MLPEs 200, an inverter 400, and a server 300. For example, the main controller 100 may include a power line communication control board.

[0048] For example, inverter 400 may include main controller 100. Alternatively, inverter 400 may be inserted between main controller 100 and the power grid (not shown). Here, inverter 400 can convert direct current (DC) power generated by multiple PV panels 10 into alternating current (AC) power and send the converted AC power to the power grid.

[0049] For example, multiple PV panels 10 can be connected in at least one of series and parallel connections. Additionally, a single MLPE 200 can be connected to a single PV panel 10, and a single MLPE 200 can be connected to multiple PV panels 10.

[0050] Each MLPE 200, 201, 202, 203 can be connected to a corresponding PV panel 10 to perform power generation on the corresponding PV panel 10 connected thereto based on operating signals received from the main controller 100. Each MLPE 200, 201, 202, and 203 can send power generation information, including power output, temperature, and fault information of the PV panel 10, to the main controller 100, enabling the identification of the power generation status.

[0051] Multiple MLPEs 200 can periodically (at each preset time) receive at least one of a plurality of operation signals with different signal levels from the main controller 100, generate a response signal for the received operation signal, and send the generated response signal to the main controller 100. For example, the operation signal may include a heartbeat signal.

[0052] Multiple MLPEs 200 can send their own unique information (e.g., serial number) along with their response signals, enabling the main controller 100 to identify which MLPEs have sent response signals.

[0053] At this point, MLPE 200 can be used as follows: Figure 1 The MLPE 200 is connected to the PV panel 10 in a one-to-one correspondence, however, the MLPE 200 may be set in a many-to-one or many-to-many relationship depending on the configuration of the PV power generation system 1, and this disclosure is not limited thereto.

[0054] MLPE 200 can be configured as multiple MLPEs connected in series, and inverter 400 or main controller 100 can be connected across the multiple MLPEs 200 connected in series. Alternatively, such as Figure 2 As shown, the main controller 100 (or inverter) can be connected to one end of a plurality of MLPEs 200, including the first to the nth MLPE (where n is a natural number of 2 or greater).

[0055] Inverter 400 is installed in a power conversion system (PCS) and is configured to perform power conversion to supply power generated by PV panel 10 to loads or the grid.

[0056] Inverter 400 can identify the maximum power point voltage by performing maximum power point tracking (hereinafter referred to as MPPT) operation to track the power and voltage at which the PV power generation system 1 generates maximum power. MPPT operation is an algorithm implemented to continuously adjust the impedance of the array of PV panels 10 or more such that the PV power generation system 1 operates near its maximum power point when conditions such as sunlight, temperature and load change.

[0057] Inverter 400 can control MLPE 200 to perform MPPT operation, thereby maximizing the power generation efficiency of PV power generation system 1. In addition, inverter 400 can monitor the operating status by analyzing various data received from PV panel 10, MLPE 200, load and grid.

[0058] The main controller 100 can generate multiple operating signals with different signal levels and periodically send these multiple operating signals to multiple MLPEs 200 connected to multiple PV panels 10. For example, refer to... Figure 2 The first MLPE 201, located at the shortest distance from the main controller 100, can receive multiple operation signals from the main controller 100 and send multiple operation signals to the second MLPE 202. The second MLPE 202 can receive multiple operation signals from the first MLPE 201 and send multiple operation signals to the third MLPE (not shown).

[0059] In this configuration, the nth MLPE 203, located furthest from the main controller 100, can receive the operation signal transmitted from the main controller 100 to the (n-1)th MLPE (not shown) via the first MLPE 201. At this time, the nth MLPE 203 can receive operation signals from multiple MLPEs, and even if the reception sensitivity of the operation signal transmitted from the main controller 100 deteriorates due to the distance between the nth MLPE 203 and the main controller 100, and impedance differences caused by component variations among the multiple MLPEs, multiple operation signals with different signal levels can still be transmitted from the main controller 100. Therefore, at least one of the multiple operation signals can be reliably received. In response to receiving at least one operation signal, each MLPE can generate a response signal for the at least one operation signal and transmit the response signal to the main controller 100.

[0060] The main controller 100 can receive a response signal for at least one operation signal from at least one MLPE that has received at least one of a plurality of operation signals that are periodically transmitted, and can control the signal level of the plurality of operation signals based on the result of receiving the response signal.

[0061] The main controller 100 can collect and output the reception results of response signals received from multiple MLPEs 200, or send the results to the server 300 (or the administrator's UE), enabling the administrator to identify the status of multiple MLPEs 200. In this case, the sending and receiving of information between the main controller 100 and the server 300 can be performed in a wired or wireless manner.

[0062] The sending and receiving of information between multiple MLPEs 200 and the main controller 100 can be performed using power line communication (PLC). With PLC, separate communication cables or wireless communication technologies are not required to send and receive information between multiple MLPEs 200 and the main controller 100, thus simplifying the installation and maintenance of the PV power generation system 1.

[0063] Figure 3 This is a block diagram illustrating an example of a main controller included in a PV power generation system according to an embodiment.

[0064] Reference Figures 1 to 3 The main controller 100 (or inverter) can be configured to include a processor 110 and a memory 120. In this case, the processor 110 can be configured to include a generation unit 111, a communication unit 112, and a signal control unit 113. However, the above-described units are merely functional configurations for describing the operation of the processor 110, and the operation of this disclosure is not limited by the division of these units.

[0065] The generation unit 111 can generate multiple operating signals with different signal levels. At this time, the generation unit 111 can generate multiple operating signals with different signal levels based on the distance from the multiple MLPEs 200 to the main controller 100 (or inverter).

[0066] The generation unit 111 can generate a single operating signal corresponding to a preset signal level, and generate multiple operating signals with different signal levels by changing the signal level of the generated single operating signal based on at least one of the following: a preset adjustment value, the distance from the multiple MLPEs 200 to the main controller 100 (or the inverter), and the separation distance between the multiple MLPEs 200. The distance from the multiple MLPEs 200 to the main controller 100 and the separation distance between the multiple MLPEs 200 can be preset or received from the server 300 (or an administrator terminal not shown).

[0067] The communication unit 112 can communicate with multiple MLPEs 200 connected to multiple PV panels 10, or it can communicate with a server 300 (or an administrator terminal).

[0068] The communication unit 112 can periodically send multiple operation signals to a plurality of MLPEs 200 (e.g., at each preset time interval), and receive response signals for the operation signals from at least one MLPE that has received at least one of the periodically sent operation signals. For example, in one embodiment, the communication unit 112 can sequentially send first to fifth operation signals with different signal levels to the plurality of MLPEs 200, and send the first to fifth operation signals every five seconds. At this time, the communication unit 112 can: after sending the first operation signal, receive MLPE unique information of at least one MLPE and a response signal for the first operation signal from at least one MLPE among the plurality of MLPEs 200; and after sending the second operation signal, receive MLPE unique information of at least one MLPE and a response signal for the second operation signal from at least one MLPE among the plurality of MLPEs 200.

[0069] Alternatively, the communication unit 112 may send first to fifth operation signals with different signal levels to a plurality of MLPEs 200 every five seconds. After sending the first to fifth operation signals, the communication unit 112 may receive unique information about the MLPE and the signal level of the operation signal received by the MLPE, as well as a response signal for the at least one operation signal, from at least one of the MLPEs 200.

[0070] The signal control unit 113 can change the signal level of the multiple operation signals generated by the generation unit 111 based on the reception results associated with the response signals from the multiple MLPEs 200, so that even if the sensitivity of the MLPEs to the operation signals deteriorates, the multiple MLPEs 200 can still receive the operation signals correctly.

[0071] In response to receiving a response signal from at least one MLPE via communication unit 112, signal control unit 113 can accumulate a count of the number of responses to the operation signal for each of the plurality of MLPEs and store the counted number of responses in memory 120. As a preset observation period elapses, signal control unit 113 can retrieve the count of responses to the operation signal for each of the plurality of MLPEs from memory 120.

[0072] When any MLPE (Multi-Level Device) responds to an operation signal with a number equal to or greater than a threshold during a preset observation period, the signal control unit 113 can fix the signal level of the operation signal received by any MLPE. At this time, the signal control unit 113 can change the signal level of the remaining operation signals among the multiple operation signals, excluding the operation signal received by any MLPE.

[0073] The signal control unit 113 can change the signal level of a portion of multiple operating signals (e.g., the remaining operating signals among the multiple operating signals excluding those received by any MLPE having a number of responses equal to or greater than a preset threshold) by adjusting the amplification rate of the operating signal using a digital variable resistor of the amplification unit for amplifying the operating signal generated by the generation unit 111, or by controlling the transistor of the amplification unit, or by using a voltage-controlled converter.

[0074] In addition, the signal control unit 113 can determine that an MLPE that has not sent a response signal to the operation signal during the error determination period is in an error state, and can generate and output an error state message about the MLPE that has not sent a response signal, or send the error state message to the server 300 (or the administrator terminal), so that the administrator can accurately and quickly identify the error state of the MLPE and respond to it.

[0075] Processor 110 may be implemented as an array of logic gates, or as a combination of a general-purpose microprocessor and memory storing a program executable on the microprocessor. For example, 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, processor 110 may include an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a field-programmable gate array (FPGA), etc. For example, 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.

[0076] The memory 120 is hardware used to store various data processed in the main controller 100, is operatively connected to the processor 110, and stores programs for processing and control of the processor 110.

[0077] The memory 120 may include random access memory (RAM) such as DRAM or SRAM, read-only memory (ROM), EEPROM, flash memory, Blu-ray or other optical disc storage devices, hard disk drive (HDD), solid-state drive (SSD), or flash memory.

[0078] Figure 4 This is a flowchart illustrating an example of an operation method of a PV power generation system according to an embodiment.

[0079] For example, such as Figure 4 As shown, the operation of a PV power generation system can be performed by the main controller (or inverter).

[0080] Reference Figure 4 In step S110, the main controller can generate multiple operating signals with different signal levels. The main controller can generate a single operating signal corresponding to a preset signal level, and generate multiple operating signals with different signal levels by changing the signal level of the generated single operating signal based on at least one of the following: a preset adjustment value, the distance from the multiple MLPEs to the main controller (or inverter) (e.g., ...). Figure 2 The distance between the first MLPE and the main controller, the distance between the second MLPE and the main controller, etc.), and the separation distance between multiple MLPEs (e.g., Figure 2 The distance between the first MLPE and the second MLPE, the distance between the (n-1)th MLPE and the nth MLPE, etc.

[0081] In the following text, reference will be made to Figure 10 Examples of multiple operating signals generated by the main controller are described.

[0082] Figure 10 This is a diagram used to illustrate multiple operating signals according to an implementation method.

[0083] Reference Figure 10 (a) According to the relevant technology, all operating signals have the same signal level and are transmitted through a single stage. Meanwhile, refer to... Figure 10 In embodiment (b), an operation signal is sent such that multiple signals with different signal levels are sent through multiple stages (stage n, stage n+a, stage n+b). Therefore, even if the MLPE receives only one of the multiple operation signals with different signal levels, the MLPE and the main controller can communicate correctly with each other.

[0084] Therefore, even if the receiving sensitivity of the operation signal sent from the main controller deteriorates due to the distance between the nth MLPE and the main controller, and the impedance difference caused by component variations among the multiple MLPEs, multiple operation signals with different signal levels can still be sent from the main controller. Thus, each MLPE can reliably receive at least one of the multiple operation signals.

[0085] Return to reference Figure 4 In step S120, the main controller can periodically send multiple operation signals to multiple MLPEs connected to multiple PV panels. For example, the main controller can sequentially send first to fifth operation signals with different signal levels every five seconds, or it can send the first to fifth operation signals together.

[0086] At step S130, the main controller can receive a response signal for an operation signal from at least one MLPE that has received at least one operation signal from a plurality of periodically transmitted operation signals. When the main controller sequentially transmits first to fifth operation signals with different signal levels to the first to tenth MLPEs, the main controller can: after transmitting the first operation signal, receive unique information of the MLPE and a response signal for the first operation signal from at least one of the first to tenth MLPEs; and after transmitting the second operation signal, receive unique information of the MLPE and a response signal for the second operation signal from at least one of the first to tenth MLPEs.

[0087] For example, when the main controller sends first to fifth operation signals with different signal levels to the first to tenth MLPEs, the main controller can receive unique information from the MLPEs and the signal level of the operation signals received by the MLPEs after sending the first to fifth operation signals.

[0088] In response to receiving a response signal from at least one MLPE during a preset observation period (e.g., 60 seconds), the main controller can accumulate and count the number of responses from each of the plurality of MLPEs to the operation signal based on unique information of the MLPE received along with the response signal, and can store the counted number of responses in memory. The main controller can accumulate and count the number of responses based on response signals received from the MLPEs in response to the operation signal, but this disclosure is not limited thereto. For example, a number of receptions indicating the accumulated number of receptions by the MLPEs to the operation signal can be received from the MLPEs as the number of responses to the operation signal, and will be referred to later... Figure 6 Provide a detailed description.

[0089] At step S140, the main controller can determine whether the number of responses of each MLPE among the plurality of MLPEs is equal to or greater than a preset threshold. At this time, the main controller can retrieve the number of responses of each MLPE to the operation signal from the memory and determine whether the number of responses of each MLPE to the operation signal among the plurality of MLPEs is equal to or greater than the current threshold.

[0090] When it is determined in step S140 that the number of responses from each of the plurality of MLPEs to the operation signal is equal to or greater than a preset threshold, the main controller can determine that all MLPEs have correctly received the operation signal. Therefore, in step S170, the main controller can fix the signal levels of the periodically transmitted plurality of operation signals. For example, in the case where the plurality of MLPEs includes the first to the tenth MLPEs, when it is determined that the number of responses from the first MLPE or the tenth MLPE is equal to or greater than the preset threshold, the main controller can fix the signal levels of the first to the fifth operation signals.

[0091] If it is not determined at step S140 that the number of responses of each of the multiple MLPEs to the operation signal is equal to or greater than a preset threshold, at step S150, the main controller may determine whether there exists any MLPE whose number of responses to the operation signal is equal to or greater than the preset threshold.

[0092] When it is determined in step S150 that there is no MLPE whose number of responses is equal to or greater than a preset threshold, in step S151, the main controller may change the signal level of multiple operation signals. The main controller sends multiple operation signals with changed signal levels, and in response to receiving a response signal for an operation signal from at least one MLPE that has received at least one of the multiple operation signals, the main controller may accumulate and count the number of responses of each of the multiple MLPEs to the operation signal. Then, the main controller may proceed to step S140.

[0093] When it is determined at step S150 that there exists any MLPE whose number of responses is equal to or greater than a preset threshold, at step S160, the main controller can fix the signal level of the operation signal received by the corresponding MLPE. Then, at step S161, the main controller changes the signal level of the remaining operation signals among the plurality of operation signals, excluding the operation signal received by the arbitrary MLPE. Additionally, the main controller sends a plurality of operation signals, including operation signals with fixed signal levels and operation signals with changed signal levels. Furthermore, in response to receiving a response signal for an operation signal from at least one MLPE that has received at least one of the plurality of operation signals, the main controller can accumulate and count the number of responses from each of the plurality of MLPEs to the operation signal. Then, the main controller can proceed to step S140. For example, the main controller sends the first to fifth operation signals to the first to tenth MLPEs, and when the threshold is 8 and the number of responses from the first MLPE to the first operation signal among the first to tenth MLPEs is 10, the number of responses from the first MLPE to the first operation signal is equal to or greater than the threshold; therefore, the signal level of the first operation signal received by the first MLPE can be fixed. On the other hand, the main controller can change the signal levels of the second to fifth operation signals, excluding the first operation signal. In this case, the main controller can change the signal levels of the second to fifth operation signals based on at least one of the following: the distance from the MLPE (second to tenth MLPE) to the main controller, and the distance between the MLPEs (second to tenth MLPE). For example, as the distance from the MLPE to the main controller or the distance between the MLPEs increases, the signal levels of the second to fifth operation signals can be changed to be higher.

[0094] When changing the signal level of the operating signal, the main controller can change the signal level by adjusting the amplification rate of the operating signal using a digital variable resistor in the amplification unit, or by controlling the transistor in the amplification unit, or by using a voltage-controlled converter, and referencing... Figure 7 and Figure 8 Please provide a detailed description.

[0095] The main controller can adaptively control the signal levels of multiple operating signals based on the received results associated with response signals from multiple MLPEs, so that operating signals can be correctly received from multiple MLPEs regardless of the surrounding environment.

[0096] Figure 5 This is a flowchart illustrating an example of an error state in an operating method for a PV power generation system according to an embodiment.

[0097] Reference Figure 5 At step S210, the main controller can control the signal levels of multiple operation signals based on the received results associated with the response signals from multiple MLPEs (see [link to relevant documentation]). Figure 4 ).

[0098] At step S220, the main controller can determine, for example, whether a preset time period (e.g., 3 minutes) for error determination has elapsed based on the time when multiple operation signals are first sent, and if it is not determined that the time period for error determination has elapsed, the main controller can proceed to step S210. In this case, the time period for error determination can be longer than the time period for observation (see...). Figure 4 (S130 in the middle).

[0099] When it is determined at step S220 that the time period for error determination has elapsed, at step S230, the main controller can determine whether there is any MLPE whose response number is less than a preset reference value.

[0100] When it is determined in step S230 that there is any MLPE whose response count is less than a preset reference value, in step S240, the main controller can generate and display an error status message for the corresponding MLPE whose response count is less than the reference value, or send the error status message to the server (or administrator terminal), so that the error status of the corresponding MLPE can be identified. In other words, the main controller can determine that any MLPE that has not sent a response signal to the operation signal during the preset time period used for error determination is in an error state, and can send an error status message about the corresponding MLPE that has not sent a response signal to the server (or administrator terminal), so that the administrator can respond to the error status of the MLPE quickly without delay.

[0101] Figure 6 This is a data flow diagram illustrating another example of the operation method of a PV power generation system according to an embodiment.

[0102] Will Figure 4 The method shown is the same as Figure 6 The methods shown are compared. Figure 6 The method shown involves receiving the number of responses to the operation signal from the MLPE, rather than accumulating and counting the number of responses to the operation signal from the main controller. Apart from the differences described above, the remaining steps are... Figure 4 The method shown and Figure 6 The methods shown are the same. Therefore, the omission of the method is unnecessary. Figure 4 The method shown and Figure 6 The description of the same configuration in the method shown.

[0103] Reference Figure 6The main controller 100 can generate multiple operation signals with different signal levels and periodically send the multiple operation signals to the MLPE 200 (steps S310 and S320).

[0104] In response to receiving at least one of a plurality of operation signals during a preset period for observation, MLPE 200 may accumulate and count the number of operation signals received (step S330). MLPE 200 may send the number of operation signals received, the signal level of the received operation signals, and unique information of MLPE to the main controller 100.

[0105] The main controller 100 can receive the number of operation signals received from the MLPE 200 as the number of responses to the operation signals, and can also receive the signal level of the operation signals and the unique information of the MLPE 200 from the MLPE 200.

[0106] When the number of responses to the operation signals received from the MLPE 200 is equal to or greater than a preset threshold, the main controller 100 can fix the signal level of the operation signals received from the MLPE 200 among the multiple operation signals periodically sent to the MLPE 200.

[0107] For example, MLPE 200 can be configured to include a processor (not shown) and a memory (not shown). Here, when at least one of a plurality of operation signals is received from the main controller 100, the processor can accumulate a count of the number of received operation signals and store the counted number of received signals and the signal level of the received operation signals in association with the unique information of MLPE 200 in the memory. In addition, the processor can send the number of received operation signals, the signal level of the operation signals, and the unique information of MLPE to the main controller 100.

[0108] Figure 7 and Figure 8 This is a diagram illustrating an example of the signal levels of multiple operating signals in a PV power generation system according to an embodiment.

[0109] The main controller (or inverter) of a PV power generation system can control the signal levels of multiple operating signals based on the received results associated with response signals from multiple MLPEs.

[0110] For example, the main controller can change the signal level of the operating signal by changing the voltage in the analog-to-digital converter (ADC) output pin of the microcontroller unit (MCU).

[0111] In this implementation, the main controller can change the signal level of the operating signal by adjusting the amplification rate of the amplification unit (AMP) in the signal transmission stage. For example... Figure 7 As shown, the main controller can change the signal level of the operating signal by adjusting the output value Vout using the first resistor R1 and the second resistor R2 of the amplification unit (e.g., a non-inverting amplifier) ​​as digital variable resistors, or by turning on / off the transistor TR or Q1 to adjust the output value Vout using a combination of the first resistor R1 and the third resistor R3 to change the signal level of the operating signal.

[0112] For example, the main controller can use a buck converter or a boost converter to change the signal level of the operating signal. Alternatively, the main controller can change the signal level of the operating signal by changing the VCC_12V power of the push-pull circuit, for example, by using a buck converter or a boost converter.

[0113] Figure 9 This is a diagram showing the power supply structure of a building with PV panels installed according to an embodiment of a PV power generation system.

[0114] Reference Figure 9 PV panels 2 can be installed on the roof of a building to generate energy.

[0115] The PV inverter 6 (or main controller) can supply the generated electricity to building 900 by converting the energy of the PV panel 2.

[0116] Meanwhile, commercial electricity transmitted through pole 3 can be supplied to the building via transformer 4.

[0117] Multiple household appliances 7 can operate by selectively receiving at least one of commercial electricity and electricity generated by PV panel 2. Meter 5 can measure the amount of electricity consumed in building 900.

[0118] Alternatively, if a separate energy storage system (ESS) is provided, the energy of PV panel 2 can be stored in the ESS.

[0119] Multiple connected PV panels 2 can form a photovoltaic module string. A photovoltaic module string is a collection of multiple photovoltaic modules and may include an output terminal.

[0120] Meanwhile, PV panel 2 may include or be connected to MLPE.

[0121] PV panel 2 may include a monitoring device for monitoring the status or power output of PV panel 2 or a fast shutdown device (RSD) for performing fast shutdown function.

[0122] In addition, at least one of the multiple PV panels and MLPE may include a communication module for power line communication.

[0123] According to embodiments of this disclosure, a PV power generation system can be provided in which a main controller sends multiple operating signals with different signal levels to an MLPE, such that even if the MLPE's sensitivity to receiving the operating signals from the main controller is degraded due to the distance from the MLPE to the main controller and impedance differences caused by component variations, the MLPE can still correctly receive the operating signals.

[0124] Furthermore, according to embodiments of this disclosure, an MLPE that fails to send a response signal during a preset time period for error determination can be identified as being in an error state, and an error state message about the MLPE that has not sent a response signal can be generated and output, enabling accurate and rapid identification and processing of the MLPE's error state.

Claims

1. An operating method executed by the main controller of a photovoltaic (PV) power generation system, the operating method comprising: Generate multiple operation signals with different signal levels; The multiple operating signals are periodically sent to multiple module-level power electronic devices (MLPEs) connected to multiple PV panels. as well as At least one MLPE receives a response signal for an operation signal from at least one of the plurality of operation signals that have been periodically transmitted, and controls the signal level of the plurality of operation signals based on the reception result of the response signal.

2. The operating method according to claim 1, wherein, The signal levels controlling the plurality of operation signals include: In response to receiving the response signal from the at least one MLPE during a preset observation period, the number of responses of each of the plurality of MLPEs to the operation signal is cumulatively counted; and In response to any number of responses from any MLPE that are equal to or greater than a preset threshold, the signal level of the operation signal received by the corresponding MLPE is fixed.

3. The operating method according to claim 2, wherein, Controlling the signal levels of the plurality of operation signals further includes: changing the signal levels of the remaining operation signals among the plurality of operation signals, excluding the operation signal received by the corresponding MLPE.

4. The operating method according to claim 1, wherein, Generating the plurality of operation signals includes: generating the plurality of operation signals with different signal levels based on the distance from the plurality of MLPEs to the main controller.

5. The operating method according to claim 1 further includes: The MLPE that fails to send the response signal during a preset time period for error determination is determined to be in an error state, and an error state message is generated and displayed regarding the MLPE that failed to send the response signal.

6. The operating method according to claim 1, wherein, Controlling the signal levels of the plurality of operating signals includes: changing the signal level of a portion of the plurality of operating signals by adjusting the amplification rate of the operating signals using a digital variable resistor of an amplification unit for amplifying the operating signals; changing the signal level of a portion of the plurality of operating signals by controlling a transistor of the amplification unit; or changing the signal level of a portion of the plurality of operating signals by using a voltage-controlled converter.

7. A main controller included in a photovoltaic (PV) power generation system, the main controller comprising: A generation unit configured to generate multiple operation signals with different signal levels; A communication unit configured to periodically transmit the plurality of operating signals to a plurality of module-level power electronic devices (MLPEs) connected to a plurality of photovoltaic (PV) panels, and to receive a response signal for an operating signal from at least one MLPE that has received at least one of the periodically transmitted plurality of operating signals. as well as A signal control unit configured to control the signal levels of the plurality of operating signals based on the reception result of the response signal.

8. The main controller according to claim 7, wherein, In response to receiving the response signal during a preset time period for observation, the signal control unit accumulates and counts the number of responses of each of the plurality of MLPEs to the operation signal, and in response to any MLPE having a number of responses equal to or greater than a preset threshold, fixes the signal level of the operation signal received by the corresponding MLPE.

9. The main controller according to claim 8, wherein, The signal control unit changes the signal level of the remaining operation signals among the plurality of operation signals, excluding the operation signal received by any of the MLPEs.

10. The main controller according to claim 7, wherein, The generation unit generates the plurality of operation signals with different signal levels based on the distance from the plurality of MLPEs to the main controller.

11. The main controller according to claim 7, wherein, The signal control unit determines that an MLPE that has not sent the response signal during a preset time period for error determination is in an error state, and generates and displays an error state message about the MLPE that has not sent the response signal.

12. The main controller according to claim 7, wherein, The signal control unit changes the signal level of a portion of the plurality of operating signals by adjusting the amplification rate of the operating signal using a digital variable resistor of the amplification unit for amplifying the operating signal, or by controlling the transistor of the amplification unit to change the signal level of a portion of the plurality of operating signals, or by using a voltage control converter to change the signal level of a portion of the plurality of operating signals.

13. An inverter for a photovoltaic (PV) power generation system, the inverter comprising: processor; as well as A memory operatively connected to the processor and configured to store at least one piece of code executed by the processor. The processor generates multiple operation signals with different signal levels and periodically sends the multiple operation signals to multiple module-level power electronic devices (MLPEs) connected to multiple photovoltaic (PV) panels. At least one MLPE receives a response signal for the operation signal from at least one of the plurality of operation signals that are periodically transmitted, and controls the signal level of the plurality of operation signals based on the reception result of the response signal.

14. The inverter according to claim 13, wherein, In response to receiving the response signal from the at least one MLPE during a preset time period for observation, the processor accumulates and counts the number of responses of each of the plurality of MLPEs to the operation signal, and in response to any MLPE having a number of responses equal to or greater than a preset threshold, fixes the signal level of the operation signal received by the corresponding MLPE.

15. The inverter according to claim 14, wherein, The processor changes the signal level of the remaining operation signals among the plurality of operation signals, excluding the operation signal received by the corresponding MLPE.

16. The inverter according to claim 13, wherein, The processor generates the plurality of operating signals with different signal levels based on the distance from the plurality of MLPEs to the inverter.

17. The inverter according to claim 13, wherein, The processor determines that an MLPE that has not sent the response signal during a preset time period for error determination is in an error state, and generates and displays an error state message about the MLPE that has not sent the response signal.

18. The inverter according to claim 13, wherein, The processor changes the signal level of a portion of the plurality of operating signals by adjusting the amplification rate of the operating signals using a digital variable resistor of an amplification unit for amplifying the operating signals, or by controlling a transistor of the amplification unit, or by using a voltage-controlled converter.

Images