Inverter and main controller for photovoltaic system, and communication error determination method for photovoltaic system

Abstract

According to an embodiment of the present invention, there is provided a communication error determination method for photovoltaic power generation, the method comprising the steps of: sending command data to one or more optimizers; receiving response data corresponding to the command data from the one or more optimizers; calculating a non-response count for each optimizer of the one or more optimizers based on the response data; and determining a communication error based on the non-response count.

Description

Technical Field

[0001] The present disclosure relates to an inverter and a main controller of a photovoltaic power generation system, and a method for determining a communication error in photovoltaic power generation. Background Art

[0002] Generally, a photovoltaic power generation system refers to a system that uses photovoltaic cells to convert photovoltaic energy into electrical energy and sends the electrical energy to the commercial power grid. During this process, no environmental pollution is generated, and the photovoltaic power generation system can be used semi-permanently.

[0003] These photovoltaic power generation systems include multiple photovoltaic panels, multiple module-level power electronics (MLPE), a main controller, and a server.

[0004] The multiple photovoltaic panels are connected in at least one of series and parallel, and multiple MLPEs can be respectively arranged in the multiple photovoltaic panels.

[0005] The multiple MLPEs can include optimizers capable of optimizing the efficiency of the electrical energy generated from the photovoltaic panels. The optimizer can optimize the power generation efficiency of the photovoltaic panels and send power generation information to the main controller, and the power generation information includes the power generation amount, temperature, and fault information of the photovoltaic panels.

[0006] The main controller can control multiple optimizers, collect the power generation information received from the multiple optimizers, and send the power generation information to the server.

[0007] The server can use the power generation information of the multiple photovoltaic panels to monitor the power generation status of the multiple photovoltaic panels.

[0008] In the case of a communication error between the main controller and the optimizer, the optimizer will immediately stop the power generation operation of the photovoltaic panel or perform the power generation operation of the photovoltaic panel using the previous operation command. In this case, the main controller will not monitor the power generation status of the photovoltaic panel.

[0009] In addition to communication errors, there may be many situations that cause the power generation operation of the photovoltaic panel to be interrupted (for example, rapid shutdown, shutdown command, damage to the photovoltaic panel), so it is impossible to determine whether the cause of the power generation interruption is a communication error or other reasons.

[0010] Therefore, it is difficult for users to analyze the cause of the power generation interruption of the photovoltaic panel and find a method to handle the interruption. Since the power generation information of the photovoltaic panel is not sent to the server, it is difficult for the server to determine the power generation status of the photovoltaic panel. Summary of the Invention

[0011] Technical Problem

[0012] The present disclosure provides a communication error determination device and method for an optimizer, through which a communication error between a master controller and an optimizer can be determined in a photovoltaic power generation system.

[0013] The present disclosure also provides a communication error determination device and method for an optimizer, through which the sensitivity of communication error determination can be adjusted by setting an error determination time according to the communication environment of a photovoltaic panel.

[0014] The technical problems obtainable from the present disclosure are not limited to the above technical problems, and other unmentioned technical problems will be clearly understood by those skilled in the art to which the present disclosure pertains from the following description.

[0015] Technical solution

[0016] According to an embodiment of the present disclosure, a communication error determination method for photovoltaic power generation includes: sending command data to one or more optimizers; receiving response data corresponding to the command data from one or more optimizers; calculating a non-response count for each of the one or more optimizers based on the response data; and determining a communication error based on the non-response count.

[0017] In the present disclosure, calculating the non-response count may include: calculating the non-response count based on the number of times the response data has not been continuously received for each of the one or more optimizers.

[0018] In the present disclosure, determining a communication error based on the non-response count may include: calculating an error count (EC) based on the number of optimizers registered for photovoltaic power generation; and determining a communication error of the optimizer corresponding to the non-response count that exceeds the error count when the non-response count exceeds the error count.

[0019] In the present disclosure, the error count may be calculated to be proportional to the error determination time, and the error count is also calculated to be inversely proportional to one or more of the following: the transmission period; or the number of registered optimizers.

[0020] In the present disclosure, the transmission period may be set based on the average response delay of each of the one or more optimizers.

[0021] In the present disclosure, the error determination time may be set considering the influence of interference.

[0022] In the present disclosure, the communication error determination method may further include: adjusting the sensitivity of communication error determination by adjusting the transmission period and the error determination time.

[0023] According to another embodiment of the present disclosure, a main controller of a photovoltaic power generation system includes: a communication unit and a processor. The communication unit is configured to: send command data to an optimizer and receive response data in response to the command data from the optimizer. The processor is configured to: calculate an error count as a communication error criterion for detecting the optimizer; accumulate a non-response count whenever response data is not received from the optimizer; and determine that a communication error of the optimizer has occurred when the non-response count exceeds the error count.

[0024] In the present disclosure, the counter can be configured to: reset the non-response count to 0 when response data is received from the optimizer.

[0025] In the present disclosure, the processor can also be configured to: set an error determination time required for determining a communication error; set a transmission period of command data between optimizers; register a sequence identifier indicating the transmission order of command data in a registration unit for each optimizer; and check the number of optimizers registered in the registration unit.

[0026] In the present disclosure, the processor can also be configured to: calculate the error count by dividing the error determination time by the product of the transmission period and the number of optimizers.

[0027] In the present disclosure, the error count can be directly proportional to the error determination time, and the error count can be inversely proportional to the number of optimizers registered in the registration unit.

[0028] In the present disclosure, the processor can also be configured to set the error determination time according to the communication environment in which a plurality of photovoltaic panels are installed.

[0029] According to another embodiment of the present disclosure, an inverter of a photovoltaic power generation system including a main controller includes a communication unit and a processor. The communication unit is configured to: send command data to one or more optimizers and receive response data in response to the command data from one or more optimizers. The processor is configured to: calculate a non-response count for each of the one or more optimizers based on the response data and determine a communication error of the one or more optimizers based on the non-response count.

[0030] Beneficial effects

[0031] According to the present disclosure, the effect of determining a communication error between the main controller and the optimizer in the photovoltaic power generation system can be achieved.

[0032] In addition, according to the present disclosure, the sensitivity of communication error determination can also be adjusted by setting the error determination time according to the communication environment of the photovoltaic panel.

[0033] The effects obtainable according to the present disclosure are not limited to the above effects, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure pertains from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a schematic diagram showing an example of a photovoltaic power generation system according to an embodiment of the present disclosure.

[0035] Figure 2 is a flowchart showing an example of a photovoltaic power generation method according to an embodiment of the present disclosure.

[0036] Figure 3 is a block diagram showing an example of a main controller included in a photovoltaic power generation system according to an embodiment of the present disclosure.

[0037] Figure 4 is a diagram showing an example of a data transmission / reception process between a main controller and an optimizer according to an embodiment of the present disclosure.

[0038] Figure 5 is a diagram for describing a method of determining a communication error of an optimizer through a data transmission / reception process between a main controller and an optimizer according to an embodiment of the present disclosure.

[0039] Figure 6 is a diagram for describing a method of determining an intermittent error through a data transmission / reception process between a main controller and an optimizer according to an embodiment of the present disclosure.

[0040] Figure 7 is a flowchart showing an example of a method of determining a communication error of an optimizer according to an embodiment of the present disclosure.

[0041] Figure 8 is a flowchart showing an example of an error determination method of a photovoltaic power generation method according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0042] The terms used in the embodiments are currently the most widely used general terms as possible, but may vary according to the intention of those skilled in the art or precedents, the emergence of new technologies, etc. In addition, in a specific case, the applicant may voluntarily select a term, and in such a case, the meaning of the term may be disclosed in the corresponding description part of the present disclosure. Therefore, the terms used herein should not be defined only based on the simple name of the term, but should be defined based on the meaning of the term and the entire content of the specification.

[0043] Throughout the specification of the present disclosure, when assuming that a certain part includes a certain component, the term "comprising" means that the corresponding component may further include other components, unless otherwise stated to the contrary.

[0044] In addition, terms such as "first" or "second" as used herein may be used to describe various components, but the components should not be limited by these terms. These terms are used to distinguish one component from another.

[0045] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the embodiments can be implemented in various forms and are not limited to the examples described herein.

[0046] Figure 1a and Figure 1b is a schematic diagram showing an example of a photovoltaic power generation system according to an embodiment of the present disclosure.

[0047] As Figure 1a shown, a photovoltaic power generation system according to an embodiment of the present disclosure may include a plurality of photovoltaic panels (10), an inverter (40) including a main controller (100), a plurality of MLPEs (200), and a server (300). Optionally, as Figure 1b shown, a photovoltaic power generation system according to another embodiment of the present disclosure may include a plurality of photovoltaic panels (10), a main controller (100), a plurality of MLPEs (200), an inverter (40), and a server (300).

[0048] A photovoltaic power generation system according to one embodiment may include a main controller (100) in the inverter (40) as Figure 1a shown, or according to another embodiment, the photovoltaic power generation system may include an inverter (40) located between the main controller (100) and the power grid 20 as Figure 1b shown. Herein, the inverter (40) may convert direct current (DC) power generated from a plurality of photovoltaic panels (10) into alternating current (AC) power and send the converted AC power to the power grid 20.

[0049] Hereinafter, for convenience, an example in which the main controller (100) shown in Figure 1a is included in the inverter (40) will be described as a basis. Although the plurality of photovoltaic panels (10) and the plurality of MLPEs (200) are collectively referred to as a group hereinafter, the photovoltaic panels (10) and the MLPEs (200) may be separated from each other and may include different types or models.

[0050] According to an embodiment, each of the plurality of photovoltaic panels (10) may refer to a photovoltaic power generation panel in units of modules. The plurality of photovoltaic panels (10) are connected in at least one of series and parallel, and a plurality of MLPEs (200) may be respectively provided in the plurality of photovoltaic panels (10). In addition, one MLPE (200) may be connected to one photovoltaic panel (10), or one MLPE (200) may be connected to a plurality of photovoltaic panels (10).

[0051] According to an embodiment, the plurality of MLPEs (200) may include module-level inverters to convert the electric energy generated from each photovoltaic panel (10) into AC power.

[0052] According to an embodiment, the plurality of MLPEs (200) may include an efficiency optimizer (210) capable of optimizing the efficiency of the electric energy generated from the photovoltaic panels (10). Although referred to as an optimizer (210) herein, the optimizer (210) may not refer to a specific type of device, but may be understood to include a device having a power efficiency optimization or maximum power point tracking (MPPT) function. The optimizer (210) may optimize the power efficiency in the following manner: when the output voltage of the connected photovoltaic panel (10) is greater than the maximum power point, it operates in a buck mode to reduce the output voltage of the connected photovoltaic panel (10); when the output voltage of the connected photovoltaic panel (10) is less than the maximum power point, it operates in a boost mode to increase the output voltage of the connected photovoltaic panel (10).

[0053] According to an embodiment, the optimizer (210) may perform a quick shutdown to stop the power generation of the photovoltaic panel (10) in an emergency. The plurality of optimizers (210) may send power generation information including the power generation amount, temperature, and fault information of the photovoltaic panel (10) to the main controller (100), and receive an operation command for optimizing the power efficiency from the main controller (100).

[0054] The information transmission / reception between the optimizer (210) and the main controller (100) may be performed using a power line communication (PLC) method. In the case of using PLC, since there is no need for a separate communication cable or wireless communication technology for transmitting / receiving information between the plurality of MLPEs (200) and the main controller (100), the installation and maintenance of the photovoltaic power generation system are more convenient. Since PLC uses the power line, it may be more affected by the line conditions or the environment compared to the case of using a communication cable.

[0055] According to an embodiment, the main controller (100) may collect the power generation information received from multiple optimizers (210) and send the power generation information to the server (300), and the server (300) may use the power generation information of the multiple photovoltaic panels (10) to monitor the power generation status of the multiple photovoltaic panels (10).

[0056] The information transmission and reception between the main controller (100) and the server (300) may be performed in a wired or wireless manner.

[0057] In an embodiment, the main controller (100) may include a processor (110), which may control multiple optimizers (210) according to the power generation status of the photovoltaic panels (10). The processor (110) may obtain response data including the power generation information of the photovoltaic panels (10) from the optimizers (210) to determine an error in the photovoltaic power generation system, where the error includes a communication error of the optimizers (210). The specific operations of the processor (110) will be described below with reference to Figure 2 be described.

[0058] To monitor the power generation status of the multiple photovoltaic panels (10), the main controller (100) may send command data to the multiple optimizers (210), and the multiple optimizers (210) may send response data including the power generation information of the photovoltaic panels (10) to the main controller (100) in response to the command data. The main controller (100) may collect the power generation information from the multiple photovoltaic panels (10). The collected power generation information of the photovoltaic panels (10) may be sent to the server (300).

[0059] The multiple optimizers (210) may send their own unique information (e.g., serial number) together with the power generation information so that the main controller (100) can identify the optimizer (210) that has sent the power generation information.

[0060] In the case where the main controller (100) randomly sends command data to the multiple optimizers (210), or in the case where the multiple optimizers (210) randomly send the power generation information and unique information to the main controller (100), a communication conflict problem may occur between the multiple optimizers (210), and it is difficult to ensure communication periodicity.

[0061] In this way, to solve the communication conflict problem and ensure communication periodicity, the main controller (100) of the photovoltaic power generation system according to an embodiment of the present disclosure may execute a program (hereinafter referred to as a registration program) for allocating a sequence identifier that indicates the order of information transmission and reception between the multiple optimizers (210).

[0062] Therefore, multiple optimizers (210) can send the power generation information of the corresponding photovoltaic panel (10) to the main controller (100) according to their respective corresponding sequence identifiers, so as to prevent communication conflicts and ensure communication periodicity.

[0063] The program for registering the sequence identifiers of multiple optimizers (210) can be executed during the initial installation of the multiple optimizers (210), or when replacing the optimizer (210) that has failed among the multiple optimizers (210).

[0064] The photovoltaic power generation system according to the embodiment can effectively shorten the registration time by automatically executing the program for registering the sequence identifiers of multiple optimizers (210).

[0065] In the case of a communication error between the main controller (100) and the optimizer (210), the optimizer (210) can immediately stop the power generation operation of the photovoltaic panel (10), or execute the power generation operation of the photovoltaic panel (10) using the previous operation command. Therefore, in the case of a communication error between the main controller (100) and the optimizer (210), the main controller (100) can not monitor the power generation state of the photovoltaic panel (10).

[0066] The reasons for the interruption of the power generation operation of the photovoltaic panel (10) can include rapid shutdown, shutdown command, and damage to the photovoltaic panel (10). In this case, since the main controller (100) can not monitor the power generation state of the photovoltaic panel (10), the user may not be able to obtain the monitoring result, and thus can not determine whether the reason for the interruption of the power generation operation is a communication error or other reasons.

[0067] Due to the above problems, it is difficult for the user to analyze the reason for the power generation interruption and find a method to handle the interruption. In the case where the main controller (100) can not monitor the state of the photovoltaic panel (10), the power generation information of the photovoltaic panel (10) may not be sent to the server (300), making it difficult for the server (300) to determine the power generation state of the photovoltaic panel (10).

[0068] To solve such problems, the photovoltaic power generation system according to an embodiment of the present disclosure can determine the error of the photovoltaic power generation system by analyzing the response data of the command data to the optimizer (210), including the communication error of the optimizer (210). Hereinafter, a method for determining the error in the photovoltaic power generation system according to the embodiment will be described.

[0069] Figure 2 is a flowchart describing an example of determining an error in a photovoltaic power generation system.

[0070] In this regard, Figure 2Each operation can be executed by the processor (110) of the main controller (100). In the following description, for ease of description, the operations of the processor (110) may be described as the operations of the main controller (100).

[0071] See Figure 2 , first, in operation (S100), the main controller (100) may send command data to one or more optimizers (210). Specifically, the main controller (100) may periodically send command data to a plurality of optimizers (210). According to an embodiment, the command data may be command data for requesting the power generation status of the photovoltaic panel (10) monitored by the optimizer (210).

[0072] In operation (S200), the main controller (100) may receive response data corresponding to the command data from one or more optimizers (210).

[0073] The main controller (100) may calculate a non-response count for each of the one or more optimizers (210) based on the response data. The non-response count calculated by the main controller (100) may be a value accumulated whenever response data is not continuously received from the optimizer (210), and may be the number of times response data has not been continuously received for each optimizer (210).

[0074] According to an embodiment, the main controller (100) may calculate an error count, which is a criterion for detecting a communication error of the optimizer (210). The main controller (100) may set an error determination time for calculating the error count and a transmission period for receiving response data from each optimizer (210). The error count may be the number of cycles repeated within the error determination time, that is, the number of times response data is received from a specific optimizer (210) within the error determination time in the absence of a communication error.

[0075] In operation (S400), the main controller (100) may determine a communication error based on the non-response count. According to an embodiment, in the case where the non-response count of a specific optimizer (210) exceeds the error count, the controller 100 may determine that a communication error has occurred in the specific optimizer (210). According to another embodiment, in the case where the non-response count is at least 1 but does not exceed the error count, the main controller (100) may determine that an intermittent error has occurred in the PLC. According to another embodiment, in the case where the number of non-response counts matches the number of registered optimizers (210), the main controller (100) may determine that an error has occurred in the main controller (100).

[0076] The main controller (100) may send the response data and information of the optimizer (210) determined to have a communication error to the server (300).

[0077] The server (300) may monitor the power generation status of the plurality of photovoltaic panels (10) based on the response data and monitor the communication status of the optimizer (210).

[0078] The determination of the communication error of the above optimizer (210) may be performed during the normal power generation operation of the photovoltaic panel (10).

[0079] Therefore, the photovoltaic power generation system according to an embodiment of the present disclosure may determine the communication error of the optimizer (210) based on whether there is a response to the command data of the main controller (100). In the case where the power generation operation of the photovoltaic panel (10) is interrupted for some reason, it may be determined whether the cause is a communication error, an intermittent communication interruption due to a power line failure, or an error in the main controller, and corresponding countermeasures may also be found.

[0080] Figure 3 It is a configuration diagram showing an example of a main controller included in a photovoltaic power generation system according to an embodiment of the present disclosure.

[0081] The main controller (100) included in the photovoltaic power generation system according to an embodiment of the present disclosure may be implemented as a communication error determination device for the optimizer (210).

[0082] As Figure 3 shown, the main controller (100) may include a communication unit 110 and a processor (110) to determine the communication error of the optimizer (210) provided in a plurality of photovoltaic panels. The processor (110) may include a setting unit (120), a registration unit (130), an inspection unit (140), a counter (150), a calculation unit (160), and a determination unit (170). In another embodiment, the processor (110) may include a communication unit (160). However, the above units are only functional components for describing the operation of the processor (110), and the operation of the present disclosure is not limited by the division of each unit.

[0083] According to an embodiment, the processor (110) may use at least one of machine learning, neural network, or deep learning algorithms as a rule-based algorithm or an artificial intelligence algorithm to perform at least part of data analysis, processing, and result information generation for performing the above operations. Examples of neural networks may include models such as Convolutional Neural Network (CNN), Deep Neural Network (DNN), and Recurrent Neural Network (RNN).

[0084] For example, the processor (110) may be implemented as an array of multiple logic gates, or may be implemented as a combination of a general-purpose microprocessor and a memory storing a program executable 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 processing device that is a combination of a DSP and a microprocessor, a combination of multiple microprocessors, a combination of one or more microprocessors combined with a DSP core, or any other such combination of components.

[0085] The setting unit (120) of the processor (110) may set an error determination time required to determine a communication error. The registration unit (130) may register a sequence identifier for each optimizer (210), and the sequence identifier indicates the transmission order in which the communication unit 110 sends command data to the optimizer (210).

[0086] The communication unit 110 may periodically send command data to multiple optimizers (210) and receive response data to the command data from the optimizers (210).

[0087] The communication unit 110 may sequentially send command data to multiple optimizers (210) according to the sequence identifier.

[0088] Figure 4 FIG. is an example showing a data transmission / reception process between a main controller and an optimizer according to an embodiment of the present disclosure.

[0089] Refer to Figure 4 In (a) of, a registration unit (130) may assign identifiers 1 to identifier n to a first optimizer PO1 210 to an nth optimizer POn 210 (where n is an integer of at least 2). When the main controller (100) sends command data to the first optimizer PO1 210, the first optimizer PO1 210 may send response data to the main controller (100) in response to the command data. When the main controller (100) may send command data to the second optimizer PO2 210 after a certain communication period, the second optimizer PO2 210 may send response data to the main controller (100) in response to the command data. Once the transmission process is completed up to the nth optimizer POn, one cycle is completed and the next cycle starts immediately.

[0090] As Figure 4 shown in (b) of, when a communication error occurs in the second optimizer PO2 210, even when the main controller (100) sends command data to the second optimizer PO2 210, the second optimizer PO2 210 will not send response data to the main controller (100), or even when the second optimizer PO2 210 sends response data, the main controller (100) will not receive the response data. In this case, the main controller (100) may not send the monitoring result of the photovoltaic panel (10) corresponding to the second optimizer PO2 210 to the server (300), making it difficult for the user to determine whether the interruption of the operation of the photovoltaic panel (10) is caused by a communication error or a problem with the photovoltaic panel (10) itself (such as damage to the photovoltaic panel (10), etc.).

[0091] To solve such problems, a communication error determination device of an optimizer according to an embodiment may determine a communication error of the optimizer (210) by checking whether the optimizer (210) responds to command data.

[0092] An inspection unit (140) may inspect the number of optimizers (210) registered in the registration unit (130). A setting unit (120) may set an error determination time required to determine a communication error, and may set a transmission period of command data between the optimizers (210).

[0093] According to an embodiment, the setting unit (120) may collect, for each optimizer (210), the time of receiving response data from each optimizer after sending data to each registered optimizer (210) (hereinafter referred to as response delay) to set a transmission period. According to an embodiment, the response delay may be the time between sending command data to each optimizer (210) and receiving response data, or may be the time between sending a registration start signal to each optimizer (210) and receiving unique information in a registration program.

[0094] The setting unit (120) may determine the transmission period based on the average value of the response delays of each optimizer (210). For example, in a case where the average value of the response delay of the first optimizer is 1 second, the average value of the response delay of the second optimizer is 0.5 second, and the transmission period is set to 0.5 second, the response data of the first optimizer and the response data of the second optimizer may be received simultaneously, which may cause a communication conflict. The setting unit (120) may set a value greater than or equal to the maximum value among the average values of the response delays of each optimizer (210) as the transmission period.

[0095] In an additional embodiment, the setting unit (120) may determine an error determination time by considering the influence of interference. For example, the error determination time may be set longer as the influence of external interference such as weather, interference from electronic devices, power line conditions, etc. increases. The error determination time according to an embodiment may be a time used as a standard for determining a communication error of the optimizer (210), and since the error determination time is set shorter, the sensitivity for determining a communication error of the optimizer (210) may be higher. Even in a case where a short communication interruption occurs due to interference within a short error determination time, this situation will be determined as a communication error of the optimizer (210), and thus, in order to prevent such mis-determination, in a case where the influence of interference is large, the error determination time may be set longer.

[0096] The calculation unit (160) may calculate an error count that is used as a standard for detecting a communication error of the optimizer (210).

[0097] As shown in Equation 1 below, the calculation unit (160) calculates the error count EC by dividing the error determination time (T) by the product of the transmission period (P) and the number N of optimizers (210) registered in the registration unit (130).

[0098] [Equation 1]

[0099] EC = T / (P * N)

[0100] For example, see Figure 5, when the communication period (P) is set to 1 second (sec), the error determination time (T) is set to 10 minutes (min), and the number N of optimizers (210) registered in the registration unit (130) is 10, the error count EC can be calculated as 60 according to Equation 1.

[0101] The error count EC can have the same meaning as the number of loops repeated within the error determination time (T).

[0102] That is, the error count EC can be proportional to the error determination time (T), inversely proportional to the transmission period T, and inversely proportional to the number N of optimizers (210) registered in the registration unit (130).

[0103] Whenever the optimizer (210) does not send response data, the counter (150) can accumulate the non-response count.

[0104] In the case where the non-response count exceeds the error count (NC), the determination unit (170) can determine that a communication error has occurred in the optimizer (210).

[0105] Figure 5 is a diagram illustrating an example of a method for determining a communication error of an optimizer through a data transmission / reception process between a main controller and an optimizer according to an embodiment of the present disclosure.

[0106] As described above, whenever the optimizer (210) does not send response data, the counter (150) can accumulate the non-response count. For example, as Figure 5 shown in (a) of, in the first loop, in the case where the second optimizer PO2 210 does not send response data, or in the case where the second optimizer PO2 210 sends response data but the main controller (100) does not receive the response data, the non-response count of the second optimizer PO2 can be counted as 1. In the second loop, in the case where the second optimizer PO2 210 does not send response data, or in the case where the second optimizer PO2 210 sends response data but the main controller (100) does not receive the response data, the non-response count of the second optimizer PO2 can be cumulatively counted as 2.

[0107] In the case where the non-response count calculated by the counter (150) exceeds the error count NC, the determination unit (170) can determine that a communication error has occurred in the optimizer (210) corresponding to the non-response counter. For example, as Figure 5As shown in (b), when the error count EC is 60 (60 cycles) and thus the non-response count of the second optimizer PO2 210 is cumulatively counted as 61, exceeding 60, it is determined that a communication error has occurred.

[0108] According to an embodiment, when the transmission cycle (P) is a preset value, the duration of one cycle can vary according to the number of optimizers (210) registered in the registration unit (130). For example, referring to Figure 5 As shown in (a), when a total of 10 optimizers, from the first optimizer PO1 to the tenth optimizer PO10, are registered in the registration unit (130), one cycle is 10 seconds (sec). However, when 20 optimizers (210) are registered in the registration unit (130), one cycle can be 20 seconds (sec).

[0109] Figure 6 FIG. is another example of a diagram for describing a method of determining a communication error of an optimizer through a data transmission / reception process between a main controller and an optimizer according to an embodiment of the present disclosure.

[0110] According to an embodiment, the counter (150) can calculate a non-response count based on the number of times of not continuously receiving response data for each of the plurality of optimizers (210).

[0111] See Figure 6 As shown in (a), in the first cycle, when the first optimizer PO1 210 does not send response data, or when the first optimizer PO1 210 sends response data but the main controller (100) does not receive the response data, the non-response count of the first optimizer PO1 can be counted as 1. In the second cycle, when the first optimizer PO1 210 does not send response data, or when the first optimizer PO1 210 sends response data but the main controller (100) does not receive the response data, the non-response count of the first optimizer PO1 can be cumulatively counted as 2.

[0112] Different from the second optimizer PO2, see Figure 6 As shown in (b), when the main controller (100) receives response data from the first optimizer PO1 210 in the 61st cycle, that is, when communication is normally executed, the non-response count of the first optimizer PO1 can be 0, and it can be determined that communication success has been achieved.

[0113] In this regard, the communication between the main controller (100) and the optimizer (210) can be performed using a power line communication method. However, due to the large area of the actual site where the photovoltaic panel (10) is installed and the long power line, the communication in the actual site is vulnerable to interference. Therefore, the communication will be interrupted frequently and intermittently.

[0114] Due to this interference-prone communication environment, an intermittent interruption in the communication between the main controller (100) and the optimizer (210) may be erroneously determined as a communication error of the optimizer (210).

[0115] To solve such problems, the counter (150) can calculate a non-response count based on the number of times response data has not been continuously received for each of the plurality of optimizers (210). In the case where the optimizer (210) sends response data even once within the error determination time after not sending response data, or in the case where the main controller (100) receives the response data, the counter (150) can reset the non-response count to 0.

[0116] According to an embodiment, the main controller (100) can adjust the sensitivity by adjusting the transmission period and the error determination time. The sensitivity can refer to the degree to which a communication error of the optimizer (210) is sensitively determined. The sensitivity can be based on the value of the error count EC, and as the error count EC increases, the sensitivity decreases.

[0117] In this regard, as described above, the error count EC is inversely proportional to the number N of optimizers (210) registered in the registration unit (130), and thus, the error count EC decreases as the number N of optimizers (210) increases.

[0118] As the number N of optimizers (210) registered in the registration unit (130) decreases, the sensitivity of communication error determination may decrease for the same error determination time (T). In the foregoing example, in the case where the number N of optimizers (210) registered in the registration unit (130) decreases from 10 to 5, the error count EC can increase to 120, and thus a communication error can be determined when the non-response count is 121. Therefore, compared with the communication error when the non-response count is 61, the sensitivity may decrease. In the presence of a preset sensitivity desired by the user, the sensitivity can be increased by increasing the error determination time (T) or by reducing the transmission period (P).

[0119] In another example, since the error count EC is proportional to the error determination time (T), the error count EC can increase as the error determination time (T) is set longer. Therefore, when the error determination time (T) increases, the sensitivity of communication error determination decreases. In the foregoing example, when the error determination time (T) increases from 10 minutes to 20 minutes, the error count EC can increase to 120. Therefore, a communication error can be determined when the no-response count is 121. Thus, compared with determining a communication error with a no-response count of 61, the sensitivity decreases. In this way, the setting unit (120) according to an embodiment of the present disclosure can adjust the sensitivity of communication error determination by setting the error determination time (T) according to the communication environment of the photovoltaic panel (10).

[0120] Optionally, according to another embodiment, even when the number N of optimizers (210) registered in the registration unit (130) changes, the main controller (100) can prevent user confusion by fixing the error determination time (T) for determining communication errors, so that the sensitivity and the error count EC also change together.

[0121] Since the error determination time (T) is the same even when the number N of optimizers (210) registered in the registration unit (130) changes, the time required to determine a communication error is the same regardless of the number N of optimizers (210), thereby providing a reference time for the user. Thus, it is possible to solve the user confusion caused by the change in the time required to determine a communication error due to the different number N of optimizers (210) registered in the registration unit (130).

[0122] The communication error determination device for an optimizer according to the embodiment of the present disclosure above can perform communication error determination on all of the plurality of optimizers (210) registered in the registration unit (130). In the case where all of the plurality of optimizers (210) are determined to have a communication error, it can be determined that an error has occurred in the main controller (100), rather than a communication error.

[0123] The communication unit 110 can send information from the optimizer (210) determined to have a communication error to the server (300). Therefore, the server (300) can identify the optimizer (210) determined to have a communication error based on the information of the optimizer (210).

[0124] Therefore, the communication error determination device of the optimizer according to an embodiment of the present disclosure can determine a communication error of the optimizer (210) based on whether there is a response to the command data of the main controller (100). In the case where the power generation operation of the photovoltaic panel (10) is interrupted for some reason, it can be determined whether the cause is a communication error, and countermeasures against the communication error can be found.

[0125] Figure 7 is a flowchart showing a method for determining a communication error of an optimizer according to an embodiment of the present disclosure.

[0126] Refer to Figure 7 , a method for determining a communication error of an optimizer according to an embodiment of the present disclosure will be described, but the same details as above will be omitted.

[0127] In operation (S10), it is determined whether a registration program for registering a sequence identifier that indicates the transmission order of command data for each optimizer (210) has started.

[0128] In operation (S20), in the case where the registration program has not started, it is determined whether there is a record of pre-registered optimizers (210).

[0129] In operation (S30), in the case where the registration program has not started and there is no record of pre-registered optimizers (210), since there is no target for communication error determination, the communication error cannot be determined. In the case where there is a record of pre-registered optimizers (210), the number of optimizers (210) registered in the registration unit (130) is known, so the operation (S40) of checking the number of registered optimizers (210) described later can be omitted, and the method can directly proceed to the operation (S50) of calculating the error count.

[0130] Since the number of optimizers (210) registered in the registration unit (130) can change in the case where the registration program starts, the checking unit (140) can check the number of optimizers (210) registered in the registration unit (130) in operation (S40).

[0131] In operation (S50), an error count that is a reference for detecting a communication error of the optimizer (210) can be calculated.

[0132] The error count EC is calculated by dividing the error determination time (T) by the product of the transmission period (P) and the number N of optimizers (210) registered in the registration unit (130).

[0133] In operation (S60), it can be determined whether the optimizer (210) has sent response data in response to the command data. It can be determined whether response data has been received from the optimizer (210).

[0134] In operation (S80), whenever response data is not received from the optimizer (210), the non-response count can be accumulated. In operation (S70), even if the optimizer (210) sends response data once within the error determination time after not sending response data, the non-response count is reset to 0.

[0135] In operation (S90), the non-response count can be compared with the error count NC to determine whether the non-response count exceeds the error count NC.

[0136] In operation (S91), in the case where the non-response count exceeds the error count NC, it can be determined that a communication error of the optimizer (210) has occurred. In the case where the non-response count does not exceed the error count NC, it can be determined that no communication error of the optimizer (210) has occurred, so that it can be determined whether to restart registration in operation (S11), and each operation in the above operations (the operations between (S10) and (S11)) can be repeated.

[0137] Hereinafter, a specific example of the communication error determination of the optimizer (210) will be described.

[0138] Figure 8 is a flowchart showing a specific example of an error determination method of a photovoltaic power generation method according to an embodiment of the present disclosure.

[0139] See Figure 8 , in operation (S811), the main controller (100) can calculate the non-response count for each of the plurality of optimizers (210) and determine whether there is an optimizer (210) whose non-response count exceeds 1. In the case where there is no optimizer (210) whose non-response count exceeds 1, in operation (S812), the main controller (100) can determine that the communication states of all the plurality of optimizers (210) are normal.

[0140] In the case where there is an optimizer (210) whose non-response count exceeds 1, in operation (S813), the main controller (100) can determine whether the calculated non-response count exceeds the error count. In the case where the non-response count does not exceed the error count, in operation (S814), the main controller (100) can determine that a power line communication error has occurred due to an intermittent communication failure.

[0141] When the non-response count exceeds the error count, in operation (S815), the main controller (100) may determine whether the number of optimizers (210) whose non-response count exceeds the error count is n, where n is the total number of registered optimizers (210). When the number of optimizers (210) whose non-response count exceeds the error count is less than n, in operation (S816), it is determined that a communication error has occurred in the corresponding optimizer (210). When the number of optimizers (210) whose non-response count exceeds the error count is n, in operation (S817), it is determined that an error has occurred in the main controller.

[0142] Therefore, the method for determining a communication error of an optimizer according to an embodiment of the present disclosure may determine a communication error of the optimizer (210) based on whether there is a response to the command data of the main controller (100). When the power generation operation of the photovoltaic panel (10) is interrupted for some reason, it can be determined whether the reason is a communication error, and countermeasures for the reason can be found.

[0143] The above method can be written as a program executable on a computer and can be implemented in a general-purpose digital computer that runs the program by using a computer-readable recording medium. The data structures used in the above method can be recorded on the computer-readable recording medium by various methods. The computer-readable recording medium may include storage media such as magnetic storage media (e.g., Read-Only Memory (ROM), Random Access Memory (RAM), Universal Serial Bus (USB), floppy disk, hard disk, etc.) and optical reading media (e.g., Compact Disc (CD)-ROM, Digital Versatile Disc (DVD), etc.).

[0144] Those of ordinary skill in the art will understand that the present disclosure can be implemented in a modified form without departing from the essential features of the present disclosure. Therefore, the disclosed method should be considered illustrative rather than restrictive, and should be interpreted by the scope of the claims rather than the previous description, including all differences within the equivalent scope.

[0145] Description of reference numerals of main elements in the drawings

[0146] 100: Main controller

[0147] 200: MLPE

[0148] 210: Optimizer

[0149] 300: Server

Claims

1. A communication error determination method for photovoltaic power generation, the communication error determination method comprising: Sending command data to one or more optimizers; Receiving response data corresponding to the command data from the one or more optimizers; Calculating a non-response count for each of the one or more optimizers based on the response data; And Determining a communication error based on the non-response count.

2. The communication error determination method according to claim 1, wherein, Calculating the non-response count includes: Calculating the non-response count based on the number of times the response data has not been continuously received for each of the one or more optimizers.

3. The communication error determination method according to claim 1, wherein, Determining the communication error based on the non-response count includes: Calculating an error count based on the number of optimizers registered for photovoltaic power generation; and Determining the communication error of the optimizer corresponding to the non-response count exceeding the error count when the non-response count exceeds the error count.

4. The communication error determination method according to claim 3, wherein, The error count is calculated to be proportional to the error determination time, and the error count is also calculated to be inversely proportional to one or more of the following: The transmission period; or The number of one or more registered optimizers.

5. The communication error determination method according to claim 4, wherein, The transmission period is set based on the average response delay of each of the one or more optimizers.

6. The communication error determination method according to claim 4, wherein, The error determination time is set considering the influence of interference.

7. The communication error determination method according to claim 1, further comprising: Adjusting the sensitivity of communication error determination by adjusting the transmission period and the error determination time.

8. A main controller of a photovoltaic power generation system, the main controller comprising: A communication unit configured to: send command data to an optimizer and receive response data in response to the command data from the optimizer; And A processor configured to: calculate an error count as a criterion for detecting a communication error of the optimizer; accumulate a non-response count whenever the response data is not received from the optimizer; and determine that a communication error of the optimizer has occurred when the non-response count exceeds the error count.

9. The master controller according to claim 8, wherein The processor is further configured to: reset the non-response count to 0 when the response data is received from the optimizer.

10. The master controller according to claim 8, wherein, The processor is further configured to: Set an error determination time required for determining the communication error; set a transmission period of command data between optimizers; register a sequence identifier for each optimizer in a registration unit, the sequence identifier indicating an order of transmission of the command data; and check the number of optimizers registered in the registration unit.

11. The main controller according to claim 10, wherein, The processor is further configured to: calculate the error count by dividing the error determination time by a product of the transmission period and the number of optimizers.

12. The main controller according to claim 10, wherein, The error count is proportional to the error determination time, and the error count is inversely proportional to the number of optimizers registered in the registration unit.

13. The main controller according to claim 10, wherein, The processor is further configured to set the error determination time according to a communication environment in which a plurality of photovoltaic panels are installed.

14. An inverter of a photovoltaic power generation system including a main controller, the inverter comprising: A communication unit, configured to: send command data to one or more optimizers and receive response data in response to the command data from the one or more optimizers; and a processor, configured to: calculate a non-response count for each of the one or more optimizers based on the response data and determine a communication error for the one or more optimizers based on the non-response count.

15. The inverter according to claim 14, wherein, The processor is further configured to: calculate the non-response count based on the number of times response data has not been continuously received for each of the one or more optimizers.

16. The inverter according to claim 14, wherein, The processor is further configured to: when determining the communication error based on the non-response count, calculate an error count based on the number of optimizers registered in the photovoltaic power generation; and when the non-response count exceeds the error count, determine the communication error of the optimizer corresponding to the non-response count that exceeds the error count.

17. The inverter according to claim 16, wherein, The error count is calculated to be proportional to the error determination time, and the error count is further calculated to be inversely proportional to one or more of the following: the transmission period; or the number of one or more registered optimizers.

18. The inverter according to claim 17, wherein, The transmission period is set based on the average response delay of each of the one or more optimizers.

19. The inverter according to claim 17, wherein, The error determination time is set considering the influence of interference.

20. The inverter according to claim 14, wherein, The processor is further configured to: adjust the sensitivity of the communication error determination by adjusting the transmission period and the error determination time.

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