Equipment matching method, controller and distributed photovoltaic inverter system

Abstract

The invention provides an equipment matching method, a controller and a distributed photovoltaic inversion system, and relates to the technical field of photovoltaic inversion. According to the distributed photovoltaic inverter system, each inverter unit is controlled by a control unit to change the current state one by one, and the mapping relation between each inverter unit and each DC / DC converter is determined according to the electrical parameter detection information of each DC / DC converter; or, controlling each DC / DC converter to change the current state one by one, and determining the mapping relation according to the electrical parameter detection information of each inversion unit. Namely, the control unit can control one of the inversion unit and the DC / DC converter to change the current state one by one and realize automatic identification of the mapping relation between the two devices according to the corresponding detection information of the other device, so that compared with manual configuration, the accuracy of the mapping relation can be improved, and the accuracy of the mapping relation is improved. Influences on power station safety and generating capacity are reduced.

Description

Technical Field

[0001] This disclosure relates to the field of photovoltaic inverter technology, and in particular to a device matching method, controller and distributed photovoltaic inverter system. Background Technology

[0002] Distributed photovoltaic (PV) inverter systems typically consist of multiple inverter units. Each inverter unit's DC terminal is connected to one or more DC / DC converters, thereby enabling power conversion for the PV strings connected to each DC / DC converter. The inverter units and their connected DC / DC converters need to perform associated actions such as power on / off and fault shutdown based on a pre-configured mapping relationship, thus achieving overall system control. For example, if any inverter unit fails, the mapping relationship will be used to shut down all DC / DC converters connected to the failed inverter unit, causing the corresponding PV strings to stop outputting power.

[0003] However, the above mapping relationship is generally configured manually, which is prone to errors and causes the above-mentioned associated actions to fail to be completed normally, thereby affecting the safety of the power plant and the power generation. Summary of the Invention

[0004] In view of the above problems, this disclosure provides a device matching method, a controller, and a distributed photovoltaic inverter system to automatically identify the mapping relationship between the inverter unit and the DC / DC converter, thereby improving the accuracy of the mapping relationship. The specific solution is as follows:

[0005] The first aspect of this disclosure provides a distributed photovoltaic inverter system, comprising: a control unit, at least two inverter units, and at least two DC / DC converters; wherein...

[0006] The AC terminals of each inverter unit are connected in parallel;

[0007] The DC terminal of the inverter unit is connected to the second terminal of at least one of the DC / DC converters;

[0008] The first terminal of the DC / DC converter is used to connect at least one photovoltaic string;

[0009] Each of the inverter units and each of the DC / DC converters are communicatively connected to the control unit;

[0010] The control unit is configured to: control each inverter unit to change its current state one by one, and determine the mapping relationship between each inverter unit and each DC / DC converter based on the electrical parameter detection information of each DC / DC converter; or, control each DC / DC converter to change its current state one by one, and determine the mapping relationship based on the electrical parameter detection information of each inverter unit.

[0011] In one possible implementation, the control unit is specifically configured to: control each inverter unit to perform a self-test when the distributed photovoltaic inverter system is started; or, control each inverter unit to adjust its DC terminal voltage when the distributed photovoltaic inverter system is running stably.

[0012] In one possible implementation, the control unit is specifically configured to: respond to an IV scan command and control each of the DC / DC converters to perform an IV scan one by one.

[0013] In one possible implementation, the electrical parameter detection information of the DC / DC converter is any one of the following: second terminal voltage detection information, second terminal current detection information, and second terminal voltage detection information and second terminal current detection information;

[0014] And / or,

[0015] The electrical parameter detection information of the inverter unit is any one of the following: DC terminal voltage detection information, DC terminal current detection information, and the DC terminal voltage detection information and the DC terminal current detection information; or, when the DC terminal of the inverter unit is connected to the second terminals of at least two DC / DC converters through at least two branches, the electrical parameter detection information of the inverter unit is any one of the following: branch voltage detection information of the branch connected to the DC terminal, branch current detection information of the branch connected to the DC terminal, and the branch voltage detection information of the branch connected to the DC terminal and the branch current detection information of the branch connected to the DC terminal.

[0016] In one possible implementation, the mapping relationship includes the correspondence between each inverter unit and each DC / DC converter connected to its DC terminal.

[0017] In one possible implementation, when the DC terminal of the inverter unit is connected to the second terminals of at least two DC / DC converters through at least two branches, and the control unit controls each DC / DC converter to change its current state one by one, the determined mapping relationship further includes: the correspondence between each DC / DC converter and the branch connected to the DC terminal of the inverter unit to which it is connected.

[0018] A second aspect of this disclosure provides a device matching method applied to a distributed photovoltaic inverter system, the device matching method comprising:

[0019] Control one of each inverter unit and each DC / DC converter in the distributed photovoltaic inverter system to change its current state one by one;

[0020] Based on the electrical parameter detection information of each inverter unit and the other of each DC / DC converter, the mapping relationship between each inverter unit and each DC / DC converter is determined.

[0021] In one possible implementation, controlling one of the inverter units and one of the DC / DC converters in the distributed photovoltaic inverter system to change its current state one by one includes:

[0022] In response to the IV scan command, each of the DC / DC converters is controlled to perform an IV scan one by one;

[0023] Alternatively, when the distributed photovoltaic inverter system is started up, each inverter unit is controlled to perform a self-test one by one.

[0024] Alternatively, when the distributed photovoltaic inverter system is running stably, the DC terminal voltage of each inverter unit is adjusted one by one.

[0025] In one possible implementation, the electrical parameter detection information of the inverter unit is any one of the following: DC terminal voltage detection information, DC terminal current detection information, and the DC terminal voltage detection information and the DC terminal current detection information;

[0026] The electrical parameter detection information of the DC / DC converter is any one of the following: second terminal voltage detection information, second terminal current detection information, and the second terminal voltage detection information and the second terminal current detection information; or, when the DC terminal of the inverter unit is connected to the second terminals of at least two DC / DC converters through at least two branches, the electrical parameter detection information of the inverter unit is any one of the following: branch voltage detection information of the branch connected to the DC terminal, branch current detection information of the branch connected to the DC terminal, and the branch voltage detection information of the branch connected to the DC terminal and the branch current detection information of the branch connected to the DC terminal.

[0027] In one possible implementation, the mapping relationship includes the correspondence between each inverter unit and each DC / DC converter connected to its DC terminal.

[0028] In one possible implementation, the DC terminal of the inverter unit is connected to the second terminals of at least two DC / DC converters through at least two branches. When controlling each DC / DC converter to change its current state one by one, the mapping relationship also includes: the correspondence between each DC / DC converter and the branch connected to the DC terminal of the inverter unit to which it is connected.

[0029] A third aspect of this disclosure provides a controller for performing the device matching method as described in the second aspect or any implementation thereof.

[0030] By employing the above technical solution, the distributed photovoltaic inverter system provided in this disclosure controls each inverter unit to change its current state one by one through a control unit, and determines the mapping relationship between each inverter unit and each DC / DC converter based on the electrical parameter detection information of each DC / DC converter; or, controls each DC / DC converter to change its current state one by one, and determines the mapping relationship based on the electrical parameter detection information of each inverter unit. That is, its control unit can automatically identify the mapping relationship between the two devices by controlling one of the inverter units and DC / DC converters to change its current state one by one, and by using the corresponding detection information of the other device. Compared with manual configuration, this improves the accuracy of the mapping relationship and reduces the impact on power plant safety and power generation. Attached Figure Description

[0031] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the originals and elements are not necessarily drawn to scale.

[0032] Figure 1 A schematic diagram of a distributed photovoltaic inverter system provided in an embodiment of this disclosure;

[0033] Figure 2 A schematic diagram of a control process of a control unit in a distributed photovoltaic inverter system provided in an embodiment of this disclosure;

[0034] Figure 3 This is a schematic diagram of another control process for the control unit in the distributed photovoltaic inverter system provided in the embodiments of this disclosure;

[0035] Figure 4 This is a schematic diagram of another control process of the control unit in the distributed photovoltaic inverter system provided in the embodiments of this disclosure;

[0036] Figure 5 This is a flowchart of a device matching method provided in an embodiment of the present disclosure. Detailed Implementation

[0037] The embodiments of this disclosure are described below with reference to the accompanying drawings. The terminology used in the Description of Embodiments section of this disclosure is for illustrative purposes only and is not intended to limit the scope of this disclosure.

[0038] The embodiments of this disclosure are described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure. Those skilled in the art will understand that with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of this disclosure are also applicable to similar technical problems.

[0039] The terms “first,” “second,” etc., used in this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the description of embodiments of this disclosure. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of units is not necessarily limited to those units, but may include other units not expressly listed or inherent to those processes, methods, products, or apparatuses.

[0040] This disclosure provides a distributed photovoltaic inverter system that automatically identifies the mapping relationship between inverter units and DC / DC converters, improving the accuracy of the mapping relationship. The specific solution is as follows:

[0041] like Figure 1 As shown, the distributed photovoltaic inverter system 10 includes: a control unit 100, at least two inverter units (INV_1 to INV_M as shown in the figure) 102, and at least two DC / DC converters (DCU_1-1 to DCU_M-N as shown in the figure) 101; wherein:

[0042] The AC terminals of each inverter unit 102 are connected in parallel, and the connection point after parallel connection serves as the AC terminal of the distributed photovoltaic inverter system 10, which is used to connect to the power grid (as shown in the figure). In practical applications, the AC terminals of each inverter unit 102 can be connected to the AC terminal of the distributed photovoltaic inverter system 10 through corresponding AC switches 103. The AC terminal of the distributed photovoltaic inverter system 10 can be connected to the power grid through a transformer. The specific connection structure of the AC terminal of the distributed photovoltaic inverter system 10 can be found in relevant technologies, and will not be described in detail here.

[0043] The DC terminal of the inverter unit 102 is connected to the second terminal of at least one DC / DC converter 101. In practical applications, the number of different inverter units 102 connected to the DC / DC converter 101 can be the same or different. For example, all inverter units 102 may be connected to the DC / DC converter 101 in the same number of times, or all inverter units 102 may be connected to the DC / DC converter 101 in the same number of times, or some inverter units 102 may be connected to the DC / DC converter 101 in the same number of times, while other inverter units 102 may be connected to the DC / DC converter 101 in the same number of times. Figure 1 The example shown uses the connection of each inverter unit 102 to N corresponding DC / DC converters 101, but it is not limited to this. Furthermore, Figure 1 In this context, the values ​​of M and N are both greater than 1. There are no restrictions here; the value depends on the specific application environment.

[0044] The first terminal of the DC / DC converter 101 is used to connect at least one photovoltaic string (PV as shown in the figure), which includes one photovoltaic module or at least two photovoltaic modules connected in series. The number of photovoltaic strings connected to each DC / DC converter 101 is not limited; different DC / DC converters 101 may have the same or different numbers of photovoltaic strings, depending on the specific application environment, all of which are within the scope of this disclosure. The specific topology of the DC / DC converter 101 is not limited; for example, it may adopt a Boost topology.

[0045] In other words, in this distributed photovoltaic inverter system 10, each photovoltaic string is connected to its corresponding inverter unit 102 after being combined through a corresponding DC / DC converter 101; to meet the maximum power requirements of the inverter unit, the inverter unit 102 often needs to have multiple DC / DC converters 101 connected in parallel. Figure 1 The example shown is that each inverter unit 102 is connected to the corresponding N-channel DC / DC converter 101.

[0046] In practical applications, the DC / DC converter 101 can be installed in the combiner box; this is not a limitation.

[0047] Each inverter unit 102 and each DC / DC converter 101 are communicatively connected to the control unit 100. Each inverter unit 102 and each DC / DC converter 101 can directly or indirectly interact with the control unit 100 through the corresponding communication interface. The specific communication method is not limited and depends on the application environment.

[0048] After the construction of the photovoltaic power station to which the distributed photovoltaic inverter system 10 belongs is completed, or after the distributed photovoltaic inverter system 10 replaces the DC / DC converter 101 or the inverter unit 102 due to a fault, the control unit 100 needs to determine the device number of the inverter unit 102 and the DC / DC converter 101 connected to it, and establish a mapping relationship between the two devices, so as to ensure that when power scheduling and power on / off functions are implemented in the future, the DC / DC converter 101 and the inverter unit 102 can be accurately scheduled for rapid response.

[0049] If the mapping relationship is configured manually, errors are likely to occur, which will affect related actions such as station IV (Current-Voltage) scanning, power dispatch, start-up and shutdown, and fault shutdown. For example, a single inverter unit 102 failure may cause the DC / DC converter 101 to be shut down erroneously, thus affecting the power generation of the entire station.

[0050] Therefore, in this embodiment, the control unit 100 is configured to: control each inverter unit 102 to change its current state one by one, and determine the mapping relationship between each inverter unit 102 and each DC / DC converter 101 based on the electrical parameter detection information of each DC / DC converter 101; or, control each DC / DC converter 101 to change its current state one by one, and determine the mapping relationship between each inverter unit 102 and each DC / DC converter 101 based on the electrical parameter detection information of each inverter unit.

[0051] In practical applications, controlling the inverter unit 102 to change its current state can specifically mean controlling the inverter unit 102 to change at least its DC terminal voltage; controlling the DC / DC converter 101 to change its current state can specifically mean controlling the DC / DC converter 101 to change at least its second terminal voltage.

[0052] Specifically, if the control unit 100 controls each inverter unit 102 to change its current state one by one, when the first inverter unit 102 (INV_1 as shown in the figure) is controlled to change its current state, the electrical parameters of the second terminals of each DC / DC converter 101 connected to it, namely the first to the Nth DC / DC converter 101 (DCU_1-1 to DCU_1-N as shown in the figure), will change accordingly. Based on the electrical parameter detection information of each DC / DC converter 101, these DC / DC converters 101 can be found and recorded accordingly. After the Mth inverter unit 102 (INV_M as shown in the figure) is controlled to change its current state and completes the search and recording of the connected DC / DC converters 101, the mapping relationship can be generated.

[0053] Alternatively, if the control unit 100 controls each DC / DC converter 101 to change its current state one by one, when the first DC / DC converter 101 (DCU_1-1 shown in the figure) is controlled to change its current state, the DC terminal electrical parameters of the first inverter unit 102 connected to it (INV_1 shown in the figure) will change accordingly. Based on the electrical parameter detection information of each inverter unit 102, this inverter unit 102 can be found and recorded accordingly. After the M×Nth DC / DC converter 101 (DCU_M-N shown in the figure) is controlled to change its current state and completes the search and recording of the connected inverter units 102, the mapping relationship can be generated.

[0054] Once the mapping relationship is determined, the control unit 100 can output or store it for subsequent associated actions and / or for the background monitoring system to display the device status.

[0055] The distributed photovoltaic inverter system 10 provided in this embodiment allows the control unit 100 to control one of the inverter unit 102 and the DC / DC converter 101 to change their current states one by one, and to automatically identify the mapping relationship between the two devices based on the corresponding detection information of the other device. That is, for a two-stage inverter system, this embodiment can achieve adaptive matching identification between the two-stage conversion circuits to determine the association between the inverter unit 102 and the DC / DC converter 101. This distributed photovoltaic inverter system 10 avoids mapping errors caused by human error settings. Therefore, compared to manual configuration, it can improve the accuracy of the mapping relationship and reduce the impact on power plant safety and power generation. Moreover, this embodiment can achieve the above-mentioned adaptive matching identification solely through software, without adding additional hardware and labor costs, making it easy to implement and promote.

[0056] Based on the previous embodiment, this embodiment provides an exemplary description of the specific operation of the control unit 100 in the distributed photovoltaic inverter system 10, for example:

[0057] When the control unit 100 controls each inverter unit 102 to change its current state one by one, it can be specifically configured to: control each inverter unit 102 to perform a self-test one by one when the distributed photovoltaic inverter system 10 is started; or, it can be configured to: control each inverter unit 102 to adjust its DC terminal voltage one by one when the distributed photovoltaic inverter system 10 is running stably.

[0058] For example, the control unit 100 can automatically identify the mapping relationship during startup self-test; specifically, when the distributed photovoltaic inverter system 10 starts up, the control unit 100 can control each inverter unit 102 to start self-test one by one, and during the self-test of the current inverter unit 102 (such as inverter unit i in the figure, i=1, 2, ..., M), it synchronously records the device number of the corresponding DC / DC converter 101 whose characteristic parameters (i.e., the above-mentioned electrical parameter detection information) change accordingly; then it controls the next inverter unit 102 (such as inverter unit i+1 in the figure) to start self-test, until all inverter units 102 have completed startup self-test, and outputs the mapping relationship obtained during startup; the specific control process is as follows: Figure 2 As shown.

[0059] In practical applications, one-click self-testing can be performed through human-computer interaction, and even self-testing can be performed before starting up every day. This can prevent the possibility of the DC / DC converter 101 and inverter unit 102 failing to associate due to equipment maintenance or incorrect DIP switches, thereby improving system safety.

[0060] Alternatively, when the distributed photovoltaic inverter system 10 is running stably, the control unit 100 can control each inverter unit 102 to adjust its DC terminal voltage one by one, for example, by raising or lowering its DC terminal voltage to a preset voltage. After the DC terminal voltage of the current inverter unit 102 (e.g., inverter unit i in the figure, i=1, 2, ..., M) stabilizes, the control unit 100 synchronously records the device number of the corresponding DC / DC converter 101 whose characteristic parameters (i.e., the aforementioned electrical parameter detection information) change accordingly. Then, it controls the next inverter unit 102 (e.g., inverter unit i+1 in the figure) to adjust its DC terminal voltage until all inverter units 102 have completed the adjustment of their DC terminal voltages, and outputs the mapping relationship obtained during the DC terminal voltage adjustment process. The specific control process is as follows: Figure 3 As shown.

[0061] Whether during startup or operation, each inverter unit 102 can be controlled to change its current state one by one to find the DC / DC converter 101 whose operating state changes accordingly, thereby achieving automatic identification of the mapping relationship.

[0062] Furthermore, when the control unit 100 controls each inverter unit 102 to change its current state one by one, the control unit 100 specifically determines the mapping relationship between each inverter unit 102 and each DC / DC converter 101 based on the electrical parameter detection information of each DC / DC converter 101. Moreover, the electrical parameter detection information of the DC / DC converter 101 can be any of the following: second terminal voltage detection information, second terminal current detection information, and second terminal voltage detection information and second terminal current detection information. That is, the electrical parameter detection information of the DC / DC converter 101 is at least one of the second terminal voltage detection information and the second terminal current detection information, depending on the specific application environment, and is not limited here.

[0063] In practical applications, this mapping relationship can include the correspondence between each inverter unit 102 and each DC / DC converter 101 connected to its DC terminal. Specifically, each device can be identified by a device number, but it is not limited to this. Any method that can distinguish each device in related technologies is feasible, depending on the specific application environment.

[0064] This embodiment provides another exemplary description of the specific operation of the control unit 100 in the distributed photovoltaic inverter system 10, for example:

[0065] When the control unit 100 controls each DC / DC converter 101 to change its current state one by one, it can be specifically configured to: respond to the IV scan command and control each DC / DC converter 101 to perform an IV scan one by one.

[0066] That is, when the control unit 100 receives the IV scan command, it determines that the IV scan is enabled. The control unit 100 controls all DC / DC converters 101 (DCU_1-1 to DCU_M-N as shown in the figure) to start IV scan one by one. During the IV scan of the current DC / DC converter 101 (e.g., DC / DC converter j, j=1, 2, ..., M×N shown in the figure), the control unit 100 synchronously records the device number of the inverter unit 102 whose characteristic parameters change accordingly. This inverter unit 102 is the inverter unit 102 connected to the DC / DC converter 101 currently performing the IV scan. Then the next DC / DC converter 101 (e.g., DC / DC converter j+1 shown in the figure) performs the IV scan until all DC / DC converters 101 have completed the IV scan. Finally, the mapping relationship between the inverter unit 102 and the DC / DC converter 101 during the IV scan is output, as follows. Figure 4 As shown.

[0067] In practical applications, the electrical parameter detection information of the inverter unit 102 can specifically refer to any of the following: DC terminal voltage detection information, DC terminal current detection information, and both DC terminal voltage detection information and DC terminal current detection information; that is, the electrical parameter detection information of the inverter unit 102 can specifically include at least one of DC terminal voltage detection information and DC terminal current detection information; no limitation is made here, depending on the specific application environment.

[0068] In one example, the mapping relationship may include the correspondence between each inverter unit 102 and each DC / DC converter 101 connected to its DC terminal.

[0069] In another example, for the same inverter unit 102, its DC terminal can be connected to the second terminals of at least two DC / DC converters 101 through at least two branches. Specifically, its DC terminal is connected to the second terminal of each DC / DC converter 101 through corresponding branches (e.g., ...). Figure 1 The connection is achieved by ZL_1-1 to ZL_1-N (or ZL_M-1 to ZL_M-N) shown in the figure; therefore, when any DC / DC converter 101 performs IV scanning, the electrical parameters of the corresponding branch connected to the DC terminal of the inverter unit 102 it is connected to change accordingly. Therefore, during the above scanning process, the changes in the branch characteristic parameters of the branch connected to the DC terminal of each inverter unit 102 can also be recorded synchronously. The branch characteristic parameters of the branch connected to the DC terminal can also include at least one of the branch voltage detection information and the branch current detection information of the branch connected to the DC terminal; that is, the electrical parameter detection information of the inverter unit 102 is any one of the following: the branch voltage detection information of the branch connected to the DC terminal, the branch current detection information of the branch connected to the DC terminal, and the branch voltage detection information and the branch current detection information of the branch connected to the DC terminal. At this time, the correspondence between the DC / DC converter 101 and the branch connected to the DC terminal of the inverter unit 102 can also be identified. That is, when the control unit 100 controls each DC / DC converter 101 to change its current state one by one, the obtained mapping relationship can also include the correspondence between each DC / DC converter 101 and the branch connected to the DC terminal of the inverter unit 102.

[0070] This embodiment can not only automatically identify the correspondence between each DC / DC converter 101 and each inverter unit 102, but also further identify the correspondence between each DC / DC converter 101 and each DC branch of the inverter unit 102 to which it is connected.

[0071] Another embodiment of this disclosure provides a device matching method applied to a distributed photovoltaic inverter system. The structure and working principle of the distributed photovoltaic inverter system can be found in the above embodiments, and will not be repeated here.

[0072] like Figure 5 As shown, the device matching method includes:

[0073] S501 controls one of the inverter units and one of the DC / DC converters in the distributed photovoltaic inverter system to change their current state one by one.

[0074] S502. Based on the electrical parameter detection information of each inverter unit and the other of each DC / DC converter, determine the mapping relationship between each inverter unit and each DC / DC converter.

[0075] As described in the above embodiments, S501 may specifically include: responding to an IV scan command and controlling each DC / DC converter to perform an IV scan one by one; or, controlling each inverter unit to perform a self-test one by one when the distributed photovoltaic inverter system is started; or, controlling each inverter unit to adjust the DC terminal voltage one by one when the distributed photovoltaic inverter system is running stably.

[0076] In practical applications, the electrical parameter detection information of the inverter unit can specifically refer to any of the following: DC terminal voltage detection information, DC terminal current detection information, and both DC terminal voltage detection information and DC terminal current detection information; or, when the DC terminal of the inverter unit is connected to the second terminals of at least two DC / DC converters through at least two branches, the electrical parameter detection information of the inverter unit can be any of the following: branch voltage detection information of the branch connected to the DC terminal, branch current detection information of the branch connected to the DC terminal, and both branch voltage detection information and branch current detection information of the branch connected to the DC terminal. The electrical parameter detection information of the DC / DC converter can specifically refer to any of the following: second terminal voltage detection information, second terminal current detection information, and both second terminal voltage detection information and second terminal current detection information.

[0077] In one example, the mapping relationship includes the correspondence between each inverter unit and each DC / DC converter connected to its DC terminal.

[0078] In another example, the DC terminal of the inverter unit is connected to the second terminals of at least two DC / DC converters through at least two branches. When controlling each DC / DC converter to change its current state one by one, the mapping relationship may also include the correspondence between each DC / DC converter and the branch connected to the DC terminal of the inverter unit to which it is connected.

[0079] The device matching method provided in this embodiment can automatically identify mapping relationships, improve the accuracy of mapping relationships, and reduce the impact on power plant safety and power generation. Moreover, this device matching method can be implemented solely through software, without adding additional hardware and labor costs, making it easy to implement and promote. Furthermore, by controlling each DC / DC converter to change its current state one by one, the correspondence between each DC / DC converter and the DC branch of its connected inverter unit can be further identified.

[0080] Another embodiment of this disclosure also provides a controller for performing the device matching method as described in any of the above embodiments.

[0081] The specific process and principle of the device matching method can be found in the above embodiments, and will not be repeated here. Specifically, the controller can be used as... Figure 1 The control unit 100 shown is shown.

[0082] The controller provided in this disclosure may include software to implement the device matching method described above. Alternatively, the controller provided in this disclosure may include hardware to implement the device matching method described above. Or, the controller provided in this disclosure may include both software and hardware, using a combination of software and hardware to execute the device matching method described above. The choice depends on the specific application environment, and all are within the scope of protection of this disclosure.

[0083] Similar or identical parts between the various embodiments in this disclosure can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the description of the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment solution according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0084] Those skilled in the art will also recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this disclosure.

[0085] The above description of the disclosed embodiments shows that the features described in the various embodiments of this disclosure can be substituted for or combined with each other, enabling those skilled in the art to implement or use this disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A distributed photovoltaic inverter system, characterized in that, include: The control unit, at least two inverter units, and at least two DC / DC converters; wherein, The AC terminals of each inverter unit are connected in parallel; The DC terminal of the inverter unit is connected to the second terminal of at least one of the DC / DC converters; The first terminal of the DC / DC converter is used to connect at least one photovoltaic string; Each of the inverter units and each of the DC / DC converters are communicatively connected to the control unit; The control unit is configured to: control each inverter unit to change its current state one by one, and determine the mapping relationship between each inverter unit and each DC / DC converter based on the electrical parameter detection information of each DC / DC converter; or, control each DC / DC converter to change its current state one by one, and determine the mapping relationship based on the electrical parameter detection information of each inverter unit.

2. The distributed photovoltaic inverter system according to claim 1, characterized in that, The control unit is specifically configured to: control each inverter unit to perform a self-test when the distributed photovoltaic inverter system is started; or, control each inverter unit to adjust its DC terminal voltage when the distributed photovoltaic inverter system is running stably.

3. The distributed photovoltaic inverter system according to claim 1, characterized in that, The control unit is specifically configured to respond to an IV scan command and control each of the DC / DC converters to perform an IV scan one by one.

4. The distributed photovoltaic inverter system according to any one of claims 1 to 3, characterized in that, The electrical parameter detection information of the DC / DC converter is any one of the following: second terminal voltage detection information, second terminal current detection information, and second terminal voltage detection information and second terminal current detection information; And / or, The electrical parameter detection information of the inverter unit is any one of the following: DC terminal voltage detection information, DC terminal current detection information, and the DC terminal voltage detection information and the DC terminal current detection information; or, when the DC terminal of the inverter unit is connected to the second terminals of at least two DC / DC converters through at least two branches, the electrical parameter detection information of the inverter unit is any one of the following: branch voltage detection information of the branch connected to the DC terminal, branch current detection information of the branch connected to the DC terminal, and the branch voltage detection information of the branch connected to the DC terminal and the branch current detection information of the branch connected to the DC terminal.

5. The distributed photovoltaic inverter system according to any one of claims 1 to 3, characterized in that, The mapping relationship includes the correspondence between each inverter unit and each DC / DC converter connected to its DC terminal.

6. The distributed photovoltaic inverter system according to claim 5, characterized in that, When the DC terminal of the inverter unit is connected to the second terminals of at least two DC / DC converters through at least two branches, and the control unit controls each DC / DC converter to change its current state one by one, the determined mapping relationship further includes: the correspondence between each DC / DC converter and the branch connected to the DC terminal of the inverter unit to which it is connected.

7. A device matching method, characterized in that, The equipment matching method, applied to distributed photovoltaic inverter systems, includes: Control one of each inverter unit and each DC / DC converter in the distributed photovoltaic inverter system to change its current state one by one; Based on the electrical parameter detection information of each inverter unit and the other of each DC / DC converter, the mapping relationship between each inverter unit and each DC / DC converter is determined.

8. The device matching method according to claim 7, characterized in that, Controlling one of the inverter units and one of the DC / DC converters in the distributed photovoltaic inverter system to change its current state one by one includes: In response to the IV scan command, each of the DC / DC converters is controlled to perform an IV scan one by one; Alternatively, when the distributed photovoltaic inverter system is started up, each inverter unit is controlled to perform a self-test one by one. Alternatively, when the distributed photovoltaic inverter system is running stably, the DC terminal voltage of each inverter unit is adjusted one by one.

9. The device matching method according to claim 7, characterized in that, The electrical parameter detection information of the inverter unit is any one of the following: DC terminal voltage detection information, DC terminal current detection information, and the DC terminal voltage detection information and the DC terminal current detection information; or, when the DC terminal of the inverter unit is connected to the second terminals of at least two DC / DC converters through at least two branches, the electrical parameter detection information of the inverter unit is any one of the following: branch voltage detection information of the branch connected to the DC terminal, branch current detection information of the branch connected to the DC terminal, and the branch voltage detection information of the branch connected to the DC terminal and the branch current detection information of the branch connected to the DC terminal. The electrical parameter detection information of the DC / DC converter is any one of the following: second terminal voltage detection information, second terminal current detection information, and second terminal voltage detection information and second terminal current detection information.

10. The device matching method according to any one of claims 7 to 9, characterized in that, The mapping relationship includes the correspondence between each inverter unit and each DC / DC converter connected to its DC terminal.

11. The device matching method according to claim 10, characterized in that, The DC terminal of the inverter unit is connected to the second terminals of at least two DC / DC converters through at least two branches. When controlling each DC / DC converter to change its current state one by one, the mapping relationship also includes: the correspondence between each DC / DC converter and the branch connected to the DC terminal of the inverter unit to which it is connected.

12. A controller, characterized in that, The controller is used to perform the device matching method as described in any one of claims 7 to 11.

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