A photovoltaic system and a method for positioning each device in a string

Abstract

The present invention provides a photovoltaic system and a method for positioning each device in a string. First, the communication host in the photovoltaic system obtains the cumulative operating time of each MLPE device, and then sorts each cumulative operating time to obtain a sorting result. Since there is a corresponding relationship between the length of the cumulative operating time of each MLPE device and the installation sequence of each device in the corresponding string, the MLPE device with each cumulative operating time can be matched to each device in the string according to the sorting result and the installation sequence of each device in the string, and then the physical position of each device in the string is determined. Therefore, it is not necessary to affix a label code to each MLPE device, and during the installation process, it is not necessary for the installation worker to record the number of each MLPE device, which simplifies the operation process, saves operation time, and reduces labor costs.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation, and in particular to a photovoltaic system and a method for positioning devices in a string. Background Art

[0002] At present, in photovoltaic systems, the application of MLPE (Module level power electronics) devices is becoming more and more common. The MLPE devices can be used to track the maximum power point of photovoltaic modules, shut down and turn on operations, or collect data and monitor them.

[0003] Usually, one or more photovoltaic modules are equipped with one MLPE device, so there are a large number of MLPE devices in the photovoltaic system. In order to facilitate subsequent maintenance and other work, it is necessary to clearly know the location of each MLPE device.

[0004] In the prior art, each MLPE device is usually affixed with a corresponding label code (such as a QR code, a barcode, etc.). During the installation of each MLPE device, the installer tears off the label code of each MLPE device and affixes it on the corresponding paper marked with the position of the MLPE device. After all MLPE devices are installed, the installation position of each corresponding MLPE device is entered into the host computer according to the paper with the label code.

[0005] Obviously, the process of determining the installation location of each MLPE device in the prior art method is too complicated, the operation time is too long, and the labor cost is increased. Summary of the invention

[0006] In view of this, an embodiment of the present invention provides a photovoltaic system and a positioning method for each device in a string to solve the problems of long operation time, complicated process and high labor cost in the prior art.

[0007] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0008] A first aspect of the present invention provides a method for positioning each device in a string, comprising:

[0009] The communication host in the photovoltaic system obtains the cumulative operating time of each MLPE device;

[0010] The communication host sorts each accumulated running time to obtain a sorting result;

[0011] The communication host determines the physical position of each device in the string according to the sorting result and the installation order of each device in the string.

[0012] Preferably, before the communication host in the photovoltaic system obtains the accumulated operating time of each MLPE device, the method further includes:

[0013] Each MLPE device stops timing synchronously.

[0014] Preferably, the MLPE devices synchronously stop timing, including:

[0015] After each MLPE device detects the synchronous stop signal, it stops timing synchronously.

[0016] Preferably, the synchronous stop signal is at least one of: an output voltage change, an output current change, an output short circuit, or a specifically coded communication signal.

[0017] Preferably, the synchronous stop signal is generated by a converter, a switch device, an additional synchronization device, a communication host or a power grid at the rear stage of each MLPE device in the photovoltaic system.

[0018] Preferably, when the synchronous stop signal is an output short circuit, the synchronous stop signal is generated by the converter being short-circuited, the switch device being short-circuited, or the string being manually short-circuited.

[0019] Preferably, after each MLPE device stops timing synchronously, the method includes:

[0020] Each MLPE device determines whether a start timing signal is detected;

[0021] If so, each MLPE device resumes timing until the synchronization stop signal is detected again, and then stops timing synchronously.

[0022] Preferably, before the communication host in the photovoltaic system obtains the accumulated operating time of each MLPE device, the method further includes:

[0023] Each MLPE device starts timing after detecting the start timing signal.

[0024] Preferably, each MLPE device detects the start timing signal in at least one of the following ways:

[0025] Each MLPE device detects a preset electrical change, each MLPE device undergoes a preset temporary or permanent mechanical change, and each MLPE device receives a timing start signal for communication transmission.

[0026] Preferably, the electrical change includes: obtaining electrical energy, or a change in an electrical parameter at the input end or the output end.

[0027] Preferably, the temporary or permanent mechanical change includes: a preset component is installed or removed, a preset component is connected or disconnected, or a relative state of a preset component is changed.

[0028] Preferably, the timing start signal is an activation signal.

[0029] Preferably, after each MLPE device stops timing synchronously and before the communication host of the photovoltaic system obtains the accumulated running time of each MLPE device, the method further includes:

[0030] Each MLPE device reports its own accumulated operating time according to the preset rules.

[0031] Preferably, it is characterized in that the preset rule is: the order of waiting for a random time length after stopping the timing.

[0032] Preferably, the preset rule is: each waits for its corresponding preset time length in order after stopping timing.

[0033] Preferably, the preset duration is: a value related to the accumulated running time, or a value related to a device serial number.

[0034] Preferably, the preset rule is: after any MLPE device reports, other devices determine their own reporting time based on the difference in accumulated running time between themselves and the reported device, and obtain the order.

[0035] Preferably, the device in the string is a photovoltaic module or a subsequent module-level power electronic MLPE device thereof.

[0036] The second aspect of the present invention also provides a photovoltaic system, comprising: a communication host and at least one string; wherein:

[0037] The string includes a plurality of photovoltaic modules connected in parallel or in series through corresponding MLPE devices;

[0038] The communication host is connected to each MLPE device through communication to implement any of the above-mentioned positioning methods for MLPE devices.

[0039] Preferably, the output ends of the main circuits in the same string are connected in parallel, and the MLPE device is a micro inverter.

[0040] Preferably, the output ends of the main circuits in the same string are connected in parallel, and the MLPE device is: a power optimizer, a circuit breaker or a component monitor;

[0041] The photovoltaic system further includes: a converter for receiving and converting the electric energy of the strings.

[0042] Preferably, the communication host is: a controller in the photovoltaic system, a proximal controller communicatively connected to the controller in the photovoltaic system, or a remote or cloud-based server or display terminal communicatively connected to any controller.

[0043] Preferably, the controller in the photovoltaic system is an independent system controller or an internal controller of the converter.

[0044] The positioning method of each device in the string provided by the above embodiment of the present invention first obtains the cumulative operating time of each MLPE device in each string by the communication host in the photovoltaic system, and then sorts each cumulative operating time to obtain a sorting result; since there is a corresponding relationship between the length of the cumulative operating time of each MLPE device and the installation order of each device in the corresponding string, the MLPE device with each cumulative operating time can be matched to each device in the string according to the sorting result and the installation order of each device in the string, and then the physical position of each device in the string is determined. The positioning method provided by the present invention does not require each MLPE device to be affixed with a label code, and during the installation process, the installation worker does not need to record the number of each MLPE device, which simplifies the operation process, saves operation time, and reduces labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0046] Figure 1 A flowchart of a method for locating each device in a string provided by an embodiment of the present invention;

[0047] Figure 2 A corresponding relationship diagram between the cumulative running time ranking of each MLPE device and the installation sequence of each photovoltaic module in a positioning method of each device in a string provided by an embodiment of the present invention;

[0048] Figure 3 A corresponding relationship diagram between another cumulative operation time ranking of each MLPE device and the installation sequence of each photovoltaic module in a positioning method of each device in a string provided by an embodiment of the present invention;

[0049] Figure 4 A corresponding relationship diagram between another cumulative operation time ranking of each MLPE device and the installation sequence of each photovoltaic module in a positioning method of each device in a string provided by an embodiment of the present invention;

[0050] Figure 5 A corresponding relationship diagram between another cumulative operation time ranking of each MLPE device and the installation sequence of each photovoltaic module in a positioning method of each device in a string provided by an embodiment of the present invention;

[0051] Figure 6 A corresponding relationship diagram between another cumulative operation time ranking of each MLPE device and the installation sequence of each photovoltaic module in a positioning method of each device in a string provided by an embodiment of the present invention;

[0052] Figure 7 A corresponding relationship diagram between another cumulative operation time ranking of each MLPE device and the installation sequence of each photovoltaic module in a positioning method of each device in a string provided by an embodiment of the present invention;

[0053] Figure 8 A flowchart of a method for positioning each device in a string provided by another embodiment of the present invention;

[0054] Fig. 9 A flowchart of a method for positioning each device in a string provided by another embodiment of the present invention;

[0055] Fig.10 A flowchart of a method for positioning each device in a string provided by another embodiment of the present invention;

[0056] Fig.11 A schematic structural diagram of a photovoltaic system provided by another embodiment of the present invention;

[0057] Fig.12 A schematic diagram of the structure of a Buck optimizer in a photovoltaic system provided by another embodiment of the present invention;

[0058] Fig.13 A schematic structural diagram of a MLPE device in a photovoltaic system as a circuit breaker provided by another embodiment of the present invention;

[0059] Fig.14 A schematic structural diagram of a converter provided in a photovoltaic system provided in another embodiment of the present invention. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] In this application, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0062] The embodiment of the present invention provides a method for positioning each device in a string to solve the problems of long operation time, complicated process and high labor cost in the prior art.

[0063] The flowchart of the positioning method is as follows Figure 1 As shown, including:

[0064] S101. A communication host in a photovoltaic system obtains the accumulated operating time of each MLPE device.

[0065] Among them, the communication host can be: a controller in the photovoltaic system, such as an internal controller or a system controller of the converter; it can also be a proximal controller that is communicatively connected to the controller in the photovoltaic system, such as a local PC; it can also be any one of a host computer, a remote terminal, and a cloud server that is communicatively connected to any of the aforementioned controllers.

[0066] In actual applications, after each MLPE device in the photovoltaic system is connected to the photovoltaic module at the input end to obtain power, the internal program of each MLPE device starts to record the accumulated running time after power-on and sends it to the communication host in the photovoltaic system. Then, step S102 is executed.

[0067] S102: The communication host sorts the accumulated running times to obtain a sorting result.

[0068] Typically, a string includes multiple photovoltaic modules and multiple MLPE devices. After the MLPE devices in the string are installed, the communication host sorts the cumulative operating time of each MLPE device to obtain a sorting result. Since the installation of each photovoltaic module and MLPE device requires a certain amount of time, the cumulative operating time of each MLPE device is different. Preferably, the cumulative operating time can be sorted from long to short. For example, the cumulative operating time of the 12 MLPE devices in the string is sorted as follows: 3, 9, 11, 4, 7, 5, 10, 8, 1, 12, 6, 2, but not limited to this. Sorting from short to long is also acceptable, and all are within the scope of protection of the present invention.

[0069] S103: The communication host determines the physical position of each device in the string according to the sorting result and the installation order of each device in the string.

[0070] Among them, the equipment in the string is a photovoltaic module or a module-level power electronic MLPE device. In a photovoltaic system, the arrangement of photovoltaic modules usually needs to be designed in advance, and the installation order is also relatively regular. For example, during the installation of the string, photovoltaic modules #1, #2...#12 and their corresponding MLPE devices are installed in sequence, but this is not limited to this. Those skilled in the art can set the installation order of photovoltaic modules according to actual needs; then each MLPE device can be matched to photovoltaic modules #1 to #12 according to the cumulative running time sorting results and the installation order of each photovoltaic module or MLPE device. The corresponding results are as follows: Figure 2 As shown, the arrows in the figure indicate the installation order of each photovoltaic module, thereby determining the physical position of each device in the string (ie, each photovoltaic module or MLPE device).

[0071] The positioning method of the MLPE device provided in this embodiment first obtains the cumulative operating time of each MLPE device by the communication host in the photovoltaic system, and then sorts the cumulative operating time to obtain the sorting result; since there is a corresponding relationship between the length of the cumulative operating time of each MLPE device and the installation order of its corresponding component, the MLPE device with each cumulative operating time can be matched to each component according to the sorting result and the installation order of each component or MLPE device, and then the physical position of each device in the string is determined. Therefore, it is not necessary to affix a label code to each MLPE device, and during the installation process, it is not necessary for the installation worker to record the number of each MLPE device, which simplifies the operation process, saves operation time, and reduces labor costs.

[0072] It is worth noting that the above Figure 2 The model of each string in the photovoltaic system shown can be established by the operator on the dedicated software of the communication host with a display interface according to actual needs, for example, on a display interface such as a handheld tablet computer, mobile phone, computer monitor installed with a corresponding APP or Web interface, and the photovoltaic components can be dragged one by one to build the string model according to the actual installation order, or all the photovoltaic components can be sorted first, and then gestures (such as Figure 2 Alternatively, a plurality of installation sequence diagrams are pre-stored, and the operator simply selects the corresponding installation sequence diagram.

[0073] like Figure 3 and Figure 4As shown in the figure, the two represent the models of strings with different installation orders respectively. The arrow lines in the figure indicate the installation order of each PV module and its corresponding MLPE device. When the installation order of the PV modules changes, the corresponding relationship between the accumulated operating time of each MLPE device and each PV module changes accordingly.

[0074] If there are multiple strings in the PV system, the PV modules and MLPE devices in each string can be sorted and matched separately based on the string. The string model can be analogous to Figure 2-Figure 4 ; The two strings can also be sorted in order. For example, the first string still has 12 PV modules and 12 MLPE devices, and the second string has PV modules #13 to #16. The first string is installed first, and then the second string is installed. The cumulative operating time of each MLPE device is sorted from long to short as follows: 3, 9, 11, 4, 7, 5, 10, 8, 1, 12, 6, 2, 17, 18, 13, 15, 14, 16, and correspond to the installation order of each PV module or MLPE device. The corresponding relationship is as follows: Figure 5 shown.

[0075] Similarly, if multiple PV panels are connected to the same MLPE device, a string model can be established in a similar manner as above, such as Figure 6 As shown, each MLPE device is connected to two photovoltaic modules. In the same way as above, each MLPE device can be mapped to a corresponding photovoltaic module. At this time, for a more accurate mapping, the installation position of the two photovoltaic modules where the MLPE device operates can be selected.

[0076] Alternatively, if not all photovoltaic modules in the string are equipped with MLPE devices, but only some photovoltaic modules are equipped with MLPE devices, the above method can also be used, that is, the accumulated operating time of each MLPE device can be sequentially matched to the corresponding photovoltaic modules, such as Figure 7 As shown, only the three photovoltaic modules #2, #9, and #8 are installed with MLPE devices, and the installation sequence of each photovoltaic module can be matched with each MLPE device.

[0077] Another embodiment of the present invention further provides a method for locating an MLPE device, the flow chart of which is as follows: Figure 8 As shown, based on the above embodiment, before executing step S101, it also includes:

[0078] S201. Each MLPE device stops timing synchronously.

[0079] Since the installation time of each MLPE device has a certain time difference, that is, the start time of each MLPE device is different, therefore, after determining that all MLPE devices have been installed, control each MLPE device to stop timing synchronously, and the accumulated running time obtained in the initial message of each MLPE device is different. Only then can each MLPE device determine its own ranking through the above-mentioned self-organizing network method.

[0080] Specifically, when each MLPE device detects a synchronous stop signal, it synchronously stops timing; wherein the synchronous stop signal may be at least one of: an output voltage change, an output current change, an output short circuit, or a specifically coded communication signal.

[0081] At this time, the above-mentioned synchronous stop signal can be generated by the converter, switch device, additional synchronization device, communication host or power grid of each MLPE device in the photovoltaic system. Taking the additional synchronization device as an example, the specific process of controlling the synchronous stop timing of each MLPE device is as follows:

[0082] After the installers have confirmed that all MLPE devices have been installed, they will connect the additional synchronization devices to the PV strings, apply voltage and current to the PV strings through the additional synchronization devices, or send a trigger signal to each MLPE device to trigger the synchronization stop timing.

[0083] It should be noted that the additional portable synchronization device is only used during system installation and debugging, and is removed after the system installation and debugging is completed.

[0084] When the PV strings or the subsequent converters are connected to the grid, the grid can generate changes in voltage, current, frequency, etc. on the PV strings, or the converters start to work in parallel after being connected to the grid, generating changes in voltage, current, frequency, etc. on the PV strings. Therefore, connecting to the grid can also generate a synchronous stop signal.

[0085] If the synchronous stop signal is: output short circuit, the source of the synchronous stop signal is any of the following:

[0086] (1) It is caused by a short circuit in the subsequent converter. For example, if the subsequent converter is a Boost circuit, the Boost switch tube is directly connected to form a string output short circuit;

[0087] (2) Caused by short-circuiting of the switch device, for example, installing a switch device on two cables of the PV string and short-circuiting the string by closing the switch device;

[0088] (3) Caused by manual short-circuiting of the strings, for example, plugging the dedicated male and female terminals on the two cables of the PV string together to form an output short circuit.

[0089] For example, in actual applications, assuming that each MLPE outputs a preset voltage to the converter after installation, such as a safety voltage of about 1V, and a string contains 12 MLPE devices connected in series, the output voltage is about 12V.

[0090] After the converter receives an input voltage of about 12V, it sends a prompt signal through the communication host to remind the operator that the current string has been installed.

[0091] After all MLPE devices are installed, the output voltage of the string can be reduced to 0 by short-circuiting the converter or the switch device through software control, or by the operator manually short-circuiting the string. When each MLPE device detects the string short-circuit, it will stop timing synchronously. When there are two strings, the two strings can be connected end to end to form a larger short-circuit loop, so that the MLPE devices in the two strings can be sequenced together.

[0092] Other methods that can trigger each MLPE device to stop timing synchronously are also within the protection scope of this application. The above are only two preferred examples and are not limited to them.

[0093] It is worth noting that there may be some special circumstances in the actual application scenario: for example, the installer only completed the installation of part of the photovoltaic string on the day, and there was not enough time to install the remaining photovoltaic components and MLPE devices. At this time, in order to avoid the randomness of the photovoltaic component power failure when night falls and interfere with the timing, the MLPE devices installed in the photovoltaic string can be triggered in advance to stop timing synchronously. Each installed MLPE device records its own cumulative operating time on the day, and when the remaining photovoltaic components and MLPE devices are installed on the second day, the installed MLPE devices are triggered to continue timing based on the timing of the previous day. That is, after executing the above step S201 and each MLPE device stops timing synchronously, it also includes the step of: each MLPE device determines whether a start timing signal is detected; if the judgment result is yes, each MLPE device resumes timing. Finally, the entire photovoltaic string is synchronously stopped, and each MLPE device in the photovoltaic string obtains its final cumulative operating time.

[0094] The remaining principles are the same as those in the above embodiment and will not be described in detail here.

[0095] Another embodiment of the present invention further provides a method for locating an MLPE device. Before executing the above step S101 and the communication host in the photovoltaic system obtains the accumulated operating time of each MLPE device, step S401 is first executed. The flow chart is as follows: Fig. 9 shown.

[0096] S401. Each MLPE device starts timing after detecting a start timing signal.

[0097] It should be noted that in the positioning methods of MLPE devices provided in the above embodiments, it is assumed that the timing starts when each MLPE device in the photovoltaic string is powered on, so the corresponding accumulated running time can be obtained by synchronously stopping the timing of each MLPE device. However, due to various factors, such as the MLPE device is pre-installed at the factory, or the photovoltaic components of the MLPE device are integrated in the junction box, as long as the MLPE device receives light, it can obtain electricity. At this time, the photovoltaic components may not have been transported to the site for installation. In this case, the accumulated running time obtained by only controlling the synchronous stopping of the timing of each MLPE device is no longer accurate.

[0098] Therefore, before executing step S101, this embodiment first executes step S401, selects corresponding start timing signals to start timing for different photovoltaic modules and MLPE devices, and then executes step S201 to obtain the accurate cumulative operating time of each MLPE device.

[0099] The start timing signal is a signal that can be detected by each MLPE device during the installation phase. Since each MLPE device is installed at a different time in the same photovoltaic system or photovoltaic string, each MLPE device detects the start timing signal at the installation time and triggers the start timing, so the start timing time of each MLPE device is also different.

[0100] Specifically, each MLPE device detects the start timing signal in at least one of the following ways: each MLPE device detects a preset electrical change, each MLPE device undergoes a preset temporary or permanent mechanical change, and each MLPE device receives a timing start signal transmitted by communication.

[0101] The electrical change may be: obtaining electric energy. For example, for a newly built photovoltaic system, the photovoltaic module and the MLPE device are usually installed together on site. The MLPE device is first fixed to the module frame or bracket, and the input end of the MLPE device is connected to the photovoltaic module. Therefore, the MLPE device installed first is first connected to the photovoltaic module, obtains electric energy first, and starts recording the accumulated running time first. Different MLPE devices have different accumulated running times due to the time difference in installation.

[0102] The same is true for the photovoltaic system renovation. The photovoltaic modules in the renovation system have been installed. When the MLPE equipment is installed, the MLPE connected to the photovoltaic modules first obtains power and starts recording the cumulative running time first. Different MLPE devices have different installation time, so the cumulative running time recorded is different.

[0103] The electrical change may also be: an electrical parameter change at the input or output end; wherein the electrical parameter refers to voltage, current or power, etc. For example, if an MLPE device detects that the input voltage exceeds 20V, it indicates that the MLPE device has been installed on the photovoltaic module and timing can be started. Alternatively, if an MLPE device detects that the output voltage is 1V, it indicates that the MLPE device has been powered on and is in the initial state, and timing can be started. Additional equipment may also be used to detect the electrical parameter changes generated at the input or output end of each MLPE device to trigger the timing of each MLPE device. For example, a voltage generating device may be connected to the output end of the MLPE device to generate a voltage change with a preset rule so that the MLPE device can accurately sense it.

[0104] However, for photovoltaic modules that are pre-installed with MLPE devices at the factory or integrated with MLPE devices in junction boxes, as long as the MLPE devices are exposed to light, they can obtain electrical energy. At this time, the photovoltaic modules may not have been transported to the site for installation, which means that the above method of triggering timing by certain electrical changes such as obtaining electrical energy is no longer effective. Therefore, the following method can also be used to detect the start timing signal: each MLPE device undergoes a preset temporary or permanent mechanical change.

[0105] In practical applications, temporary or permanent mechanical changes in each MLPE device may be: a preset component is installed or removed, a preset component is connected or disconnected, or the relative state of the preset component is changed.

[0106] Among them, the preset components in the MLPE device are removed. For example, the MLPE device is pre-installed with a plug when it leaves the factory, which is used to connect or disconnect the connection between two internal nodes. During the installation stage of the MLPE device or the component pre-installed / integrated with the MLPE device, the plug is temporarily or permanently removed to change the connection mode between the two internal nodes. After the MLPE device senses the change in the connection mode between the two nodes, it triggers the start of timing. The accessory can also be an electromagnetic induction device, such as a magnetic sticker, an accessory with an NFC near-field communication chip, etc. When the accessory is temporarily or permanently removed, the MLPE senses the change in the magnetic field and the change in the communication signal, triggering the start of timing.

[0107] Similarly, preset components are installed. For example, a socket is reserved in the MLPE device when it leaves the factory. At the installation site of the MLPE device or photovoltaic module, an accessory needs to be inserted to trigger the timing. The accessory can be an accessory that comes with the MLPE device packaging, or a tool such as a screwdriver commonly used in on-site construction. The accessory can be permanently removed or inserted to trigger the timing of the MLPE device, or temporarily removed or inserted once. For example, a screwdriver is inserted once and then pulled out to trigger the timing. The accessory can also be an electromagnetic induction device, such as a magnetic sticker, an accessory with an NFC near-field communication chip, etc. When the accessory is temporarily or permanently added to the MLPE device, the MLPE senses changes in the magnetic field and communication signal, triggering the start of timing. The preset components installed or removed in the above MLPE device are only some examples of this embodiment and are not limited to this.

[0108] When the preset components of each MLPE device are connected, for example, when the MLPE device or the component pre-installed / integrated with the MLPE device leaves the factory, the output terminals are in a floating state. At the installation site, the output terminals are briefly connected so that the MLPE device can sense it and start triggering the timing.

[0109] Alternatively, the preset components of each MLPE device are disconnected. For example, when the MLPE device or the component pre-installed / integrated with the MLPE device leaves the factory, the two ends of the output terminal are in a short-circuited state. At the installation site, the output terminals are unplugged so that the MLPE device can sense it and start triggering the timing.

[0110] Furthermore, the relative state of the preset components changes. For example, a button, knob or DIP switch is reserved on the MLPE device. At the installation site, the timing of the MLPE device is triggered by changing the state of the button, knob or DIP switch.

[0111] In addition, the method for detecting the start timing signal may also be: each MLPE device receives the timing start signal transmitted by communication; in actual application, an external device may be used to transmit the timing start signal to the MLPE device, that is, the external communication signal may be used to trigger each MLPE device to start timing. For example, a communication signal is generated by a portable device such as a mobile phone, a smart wearable device with a communication function (such as a smart bracelet, smart glasses, a smart ring, etc.); then, a communication technology suitable for short-range communication, such as NFC near-field communication, Bluetooth communication, etc., is used. When the mobile phone, the smart wearable device with a communication function, etc. is brought close to the MLPE device, the communication signal is sent to the MLPE device to trigger the MLPE device to start timing. It should be noted that the advantage of using short-range communication is that when a certain MLPE device is triggered to start timing, other MLPE devices that are closer will not be triggered by mistake.

[0112] The communication signal for triggering timing can also be used as an activation signal for the MLPE device. When the MLPE device is in an inactive state, it outputs a safe voltage, and when activated, it can output power normally.

[0113] The remaining principles are the same as those in the above embodiment and will not be described in detail here.

[0114] Another embodiment of the present invention further provides a method for positioning an MLPE device. In the above embodiment, after each MLPE device stops timing synchronously, and before each MLPE device reports its own accumulated running time to a communication host in a photovoltaic system, in order to avoid signal conflicts when reporting their own accumulated running time, the positioning method provided in this embodiment is as follows: Fig.10 As shown, it also includes:

[0115] S301. Each MLPE device reports its own accumulated operating time according to a preset rule.

[0116] After each MLPE device stops timing synchronously, it will actively report its own accumulated running time to the communication host in the photovoltaic system. In order to reduce the probability of signal conflict between each MLPE device, each MLPE device can report its own accumulated running time according to a preset rule; wherein, the preset rule can be obtained by the following method:

[0117] The first method is to wait for a random time after stopping the timing and then report. The random time corresponding to each MLPE device may be different. Even if there are the same ones, the number will be small and will not cause conflicts.

[0118] The second method: After stopping the timing, wait for the corresponding preset time to report. It should be noted that the preset time can be obtained according to the respective cumulative running time, for example, it can be set to a value related to the cumulative running time (positively or negatively correlated). For example, after setting the time when the MLPE device actively reports to the T time when the timing is stopped, T can be any value, such as T = cumulative running time / 3600. Assuming that the cumulative running time of MLPE device 1 is 62 minutes and 33 seconds, and the cumulative running time of MLPE device 2 is 57 minutes and 15 seconds, the time when MLPE device 1 actively reports after stopping the timing is: 62 minutes and 33 seconds / 3600 = 1.0425 seconds, and the time when MLPE device 2 actively reports after stopping the timing is: 57 minutes and 15 seconds / 3600 = 0.9542 seconds, and so on. Since the cumulative running time is not the same, the time when each MLPE device actively reports will also be different. Alternatively, the preset duration is set to a value related to the serial number of each MLPE device. For example, the serial number of each MLPE device (or part of the serial number) is converted into a time for actively reporting the cumulative operating time. Since the serial number of each MLPE device is different, the converted active reporting time must also be different.

[0119] The third method: After any MLPE device reports, other devices determine their own reporting time based on the difference in cumulative running time between themselves and the reported devices. Specifically, after any MLPE device reports its own cumulative running time, other MLPE devices receive and parse the cumulative running time, obtain the difference in cumulative running time between themselves and the reported devices, and then determine their own reporting time; for example, after MLPE device 1 actively reports, MLPE device 2 calculates the time difference between its own cumulative running time and MLPE device 1 as 7 minutes and 24 seconds, and can report the cumulative running time after 7 minutes and 24 seconds / 360=1.233s.

[0120] It should be noted that the above three methods are only some examples of this embodiment, but are not limited to this. As long as the preset rules can avoid signal conflicts among various MLPE devices, they are all within the protection scope of the present invention.

[0121] The remaining principles are the same as those in the above embodiment and will not be described in detail here.

[0122] Another embodiment of the present invention further provides a photovoltaic system, the structural schematic diagram of the system is as shown in Fig.11 As shown, it includes: a communication host 110, and at least one group string 120; wherein,

[0123] The string 120 includes a plurality of MLPE devices connected in parallel (eg Fig.11 as shown) or in series (as Fig.14The communication host 110 is connected to each MLPE device through communication to implement the positioning method of each device in any group string provided in the above embodiment.

[0124] In practical applications, the MLPE device in the string 120 can be: a power optimizer for maximum power point tracking (MPPT) of photovoltaic modules, or a switch for opening and closing photovoltaic modules, or a module monitor. At this time, the output ends of the main circuits in the same string are connected in series in sequence; the power optimizer is divided into two types: DC power optimizer and AC power optimizer. The DC power optimizer converts the input low-voltage DC into an output low-voltage DC, and then connects it in series into high-voltage DC. The AC power optimizer converts the input low-voltage DC into an output low-voltage AC, and then connects it in series into high-voltage AC. If the MLPE device is a micro inverter, the output ends of the main circuits in the same string are connected in parallel, but it is not limited to this. Fig.12 and Fig.13 As shown in the figure, they are the basic structures of Buck type optimizer and shutdown device respectively.

[0125] It should be noted that if the MLPE device is a micro-inverter, it can be directly output to the grid without the need for a subsequent converter (such as Fig.11 As shown). However, the MLPE device is a Buck type optimizer or circuit breaker, and still requires a subsequent converter to receive and convert the power of the string. At this time, the structural diagram of the photovoltaic system is as follows Fig.14 As shown, the converter can be a DCDC converter or a DCAC converter, such as a photovoltaic inverter or an energy storage converter, but is not limited to this. If the MLPE device is an AC optimizer, the low-voltage AC outputs of multiple AC optimizers are connected in series to form a high-voltage AC, which can be directly connected to the grid. Fig.14 The subsequent converter can also be omitted.

[0126] The communication host 110 can be a controller inside the photovoltaic system, such as an independent system controller or an internal controller of a converter; it can also be a proximal controller that is communicatively connected to the controller in the photovoltaic system, such as a local PC; it can also be a remote or cloud-based server, mobile phone or other display terminal that is communicatively connected to any of the aforementioned controllers, but is not limited to this.

[0127] The communication between the communication host 110 and each MLPE device can be wired communication, such as RS485 or Ethernet, or wireless communication, such as WIFI, Bluetooth, ZigBee (ZigBee protocol), Lora (a type of low-power wide area network), etc., or it can be a power line carrier communication, all of which are within the protection scope of the present invention.

[0128] Furthermore, the remaining principles are the same as those in the above embodiment and will not be described in detail here.

[0129] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without creative work.

[0130] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0131] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for positioning each device in a string, characterized in that: include: The communication host in the photovoltaic system obtains the cumulative operating time of each MLPE device; The communication host sorts each accumulated running time to obtain a sorting result; The communication host determines the physical position of each device in the string according to the sorting result and the installation order of each device in the string; wherein the installation order is the order in which each device in the string is installed at the installation position.

2. The method for positioning each device in a string according to claim 1, characterized in that: Before the communication host in the photovoltaic system obtains the accumulated operating time of each MLPE device, the method further includes: Each MLPE device stops timing synchronously.

3. The method for positioning each device in a string according to claim 2, characterized in that: The MLPE devices synchronously stop timing, including: After each MLPE device detects the synchronous stop signal, it stops timing synchronously.

4. The method for positioning each device in a string according to claim 3, characterized in that: The synchronous stop signal is at least one of: an output voltage change, an output current change, an output short circuit, or a specifically coded communication signal.

5. The method for positioning each device in a string according to claim 4, characterized in that: The synchronous stop signal is generated by a converter, a switch device, an additional synchronization device, a communication host or a power grid at the rear stage of each MLPE device in the photovoltaic system.

6. The method for positioning each device in a string according to claim 5, characterized in that: When the synchronous stop signal is an output short circuit, the synchronous stop signal is generated by the converter being short-circuited, the switch device being short-circuited, or the string being manually short-circuited.

7. The method for positioning each device in a string according to claim 3, characterized in that: After the MLPE devices synchronously stop timing, the method includes: Each MLPE device determines whether a start timing signal is detected; If so, each MLPE device resumes timing until the synchronization stop signal is detected again, and then stops timing synchronously.

8. The method for positioning each device in a string according to claim 1, characterized in that: Before the communication host in the photovoltaic system obtains the accumulated operating time of each MLPE device, the method further includes: Each MLPE device starts timing after detecting the start timing signal.

9. The method for positioning each device in a string according to claim 8, characterized in that: Each MLPE device detects the start timing signal in at least one of the following ways: Each MLPE device detects a preset electrical change, each MLPE device undergoes a preset temporary or permanent mechanical change, and each MLPE device receives a timing start signal for communication transmission.

10. The method for positioning each device in a string according to claim 9, characterized in that: The electrical changes include: obtaining electrical energy, or changes in electrical parameters at the input or output end.

11. The method for positioning each device in a string according to claim 9, characterized in that: The temporary or permanent mechanical changes include: a preset component being installed or removed, a preset component being connected or disconnected, or a relative state of a preset component being changed.

12. The method for positioning each device in a string according to claim 9, characterized in that: The timing start signal is an activation signal.

13. The method for positioning each device in a string according to claim 2, characterized in that: After each MLPE device stops timing synchronously and before the communication host of the photovoltaic system obtains the accumulated running time of each MLPE device, the method further includes: Each MLPE device reports its own accumulated operating time according to the preset rules.

14. The method for positioning each device in a string according to claim 13, characterized in that: The preset rule is: each waits for a random time length after stopping the timing.

15. The method for positioning each device in a string according to claim 13, characterized in that: The preset rule is: each waits for its corresponding preset time length in order after stopping timing.

16. The method for positioning each device in a string according to claim 15, characterized in that: The preset duration is: a value related to the accumulated running time, or a value related to the device serial number.

17. The method for positioning each device in a string according to claim 13, characterized in that: The preset rule is: after any MLPE device reports, other devices determine their own reporting time based on the difference in accumulated running time between themselves and the reported device, and obtain the order.

18. The method for positioning each device in a string according to any one of claims 1 to 17, characterized in that: The equipment in the string is a photovoltaic module or a subsequent module-level power electronic MLPE device.

19. A photovoltaic system, characterized in that: include: A communication host and at least one group string; wherein, The string includes a plurality of photovoltaic modules connected in parallel or in series through corresponding MLPE devices; The communication host is connected to each MLPE device through communication to implement the positioning method of the MLPE device as described in any one of claims 1-18.

20. The photovoltaic system according to claim 19, characterized in that: The output ends of the main circuits in the same string are connected in parallel, and the MLPE device is a micro inverter.

21. The photovoltaic system according to claim 19, characterized in that: The output ends of the main circuits in the same string are connected in parallel, and the MLPE device is: a power optimizer, a circuit breaker or a component monitor; The photovoltaic system further includes: a converter for receiving and converting the electric energy of the strings.

22. The photovoltaic system according to any one of claims 19 to 21, characterized in that: The communication host is: a controller in the photovoltaic system, a proximal controller that is communicatively connected to the controller in the photovoltaic system, or a remote or cloud-based server or display terminal that is communicatively connected to any controller.

23. The photovoltaic system according to claim 22, characterized in that: The controller in the photovoltaic system is an independent system controller or an internal controller of the converter.

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