An inverter and a direct current branch current calibration method thereof

Abstract

The application provides an inverter and a direct current branch current calibration method thereof. The direct current branch current calibration method comprises a branch calibration process performed for each branch of the direct current side of the inverter circuit of the inverter. The branch calibration process comprises: obtaining current collection results when a preset current value is injected into the corresponding branch; then determining a relationship parameter between the current collection results and the preset current value, and storing the relationship parameter; when the inverter is actually connected to the grid, the relationship parameter can be called to correct the actual current collection results of the corresponding branch, and the corrected branch current can be applied to subsequent fault diagnosis and power generation control, thereby avoiding the subsequent influence caused by the low current detection accuracy in the prior art. Moreover, the whole process can be realized by software, without the need to increase high-precision current collection devices, thereby avoiding the increase of system cost and maintenance difficulty.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to an inverter and a method for calibrating its DC branch current. Background Technology

[0002] Currently, in inverter applications, inaccurate DC current data for each branch is frequently obtained due to insufficient sampling accuracy of the DC current acquisition device. Inaccurate DC branch current data can affect system fault diagnosis and power generation.

[0003] To address this issue, existing technologies employ high-precision current acquisition devices to improve the sampling accuracy of the DC branch currents of the inverter. However, this requires the addition of new hardware, leading to higher system hardware costs and inconvenient on-site maintenance. Summary of the Invention

[0004] In view of this, this application provides an inverter and a method for calibrating its DC branch current to avoid the problem of inaccurate DC branch current detection results of the inverter, while avoiding the increase in system cost and maintenance difficulty.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] The first aspect of this application provides a method for calibrating the DC branch current of an inverter, including a branch calibration process performed separately for each branch on the DC side of the inverter circuit in the inverter, the branch calibration process including:

[0007] When a preset current value is injected into the corresponding branch, the current acquisition result is obtained.

[0008] Based on the current acquisition results and the preset current value, determine the relationship parameter between the two;

[0009] The relationship parameters are stored so that the inverter can correct the actual current acquisition results of the corresponding branch when actually connected to the grid.

[0010] Optionally, when a preset current value is injected into the corresponding branch, the current acquisition results are obtained, including:

[0011] When the corresponding branch is injected with a current of different preset current values ​​at least twice, the corresponding current acquisition results are obtained respectively.

[0012] Optionally, based on the current acquisition results and the preset current value, a relationship parameter between the two is determined, including:

[0013] Based on the preset current values ​​and the corresponding current acquisition results, linear fitting is performed to determine the relationship parameters.

[0014] Optionally, when performing linear fitting, the fitting is specifically based on the least squares method.

[0015] Optionally, the branch calibration process, after determining the relational parameters, further includes:

[0016] When the corresponding branch is injected with the test current value, the test acquisition result of its current is obtained;

[0017] The test current value and the test acquisition results are verified using the aforementioned relationship parameters;

[0018] If the verification is successful, then proceed to the step of storing the relation parameters;

[0019] If the verification fails, return to the step of obtaining the current acquisition result when the preset current value is injected into the corresponding branch, until the verification is successful.

[0020] Optionally, the test current value and the test acquisition result are verified using the relationship parameters, including:

[0021] Substitute either the test current value or the test acquisition result into the relational function of the relational parameters;

[0022] Determine whether the absolute value of the difference between the test current value and another of the test acquisition results and the calculated result after substitution exceeds a preset accuracy threshold.

[0023] If the absolute value does not exceed the preset precision threshold, the verification is considered successful.

[0024] If the absolute value exceeds the preset precision threshold, the verification is deemed unsuccessful.

[0025] Optionally, when performing the branch calibration process for each branch, the branch calibration process is performed sequentially for each branch.

[0026] Optionally, the branch calibration process is performed sequentially for each branch, including:

[0027] Registers are allocated to each branch to store the calibration identifier code; the initial value of the calibration identifier code for each branch is 0.

[0028] Read the calibration identification codes of each branch in sequence;

[0029] After each read, if the calibration identifier code of the current branch is 0, the branch calibration process is performed on it, and the calibration identifier code is set to 1 after the branch calibration process is completed, until the calibration identifier code of each branch is 1.

[0030] Optionally, before performing the branch calibration process on each branch individually, the method further includes:

[0031] Received the start calibration command.

[0032] Optionally, when the inverter is actually connected to the grid, after correcting the actual current acquisition results of each branch, it also includes: outputting the corrected acquisition results.

[0033] A second aspect of this application provides an inverter, comprising: a control system, an inverter circuit, and at least one current acquisition device; wherein,

[0034] The inverter circuit has at least one branch connected to its DC side;

[0035] The current acquisition device is used to acquire the current of the corresponding branch and generate corresponding current acquisition results to be output to the control system.

[0036] The inverter circuit is controlled by the control system, which is used to perform the DC branch current calibration method of the inverter as described in any of the first aspects above.

[0037] Optionally, the control system includes: a processor and an embedded intelligent control processing unit; wherein,

[0038] The processor is used to receive each of the current acquisition results and forward them to the embedded intelligent control processing unit;

[0039] The embedded intelligent control processing unit is used to execute the DC branch current calibration method.

[0040] Optionally, it also includes: DC / DC conversion circuits connected to each branch.

[0041] The DC branch current calibration method for inverters provided in this application includes a branch calibration process performed separately for each branch on the DC side of the inverter circuit. This branch calibration process includes: acquiring the current acquisition result when a preset current value is injected into the corresponding branch; determining the relationship parameter between the current acquisition result and the preset current value, and storing the relationship parameter; when the inverter is actually connected to the grid, this relationship parameter can be called to correct the actual current acquisition result of the corresponding branch. The corrected branch current can then be used for fault diagnosis and power generation control, avoiding the subsequent impacts caused by low current detection accuracy in existing technologies. Moreover, the entire process can be implemented solely through software, eliminating the need for a high-precision current acquisition device and avoiding increased system cost and maintenance difficulty. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0043] Figure 1 A flowchart of the branch calibration process in the DC branch current calibration method for the inverter provided in this application embodiment;

[0044] Figure 2 Another flowchart of the branch calibration process in the DC branch current calibration method for the inverter provided in the embodiments of this application;

[0045] Figure 3 A flowchart of the DC branch current calibration method for an inverter provided in this application embodiment;

[0046] Figure 4 This is a schematic diagram of the inverter provided in an embodiment of this application;

[0047] Figure 5 This is another structural schematic diagram of the inverter provided in the embodiments of this application;

[0048] Figure 6 This is another structural schematic diagram of the inverter provided in an embodiment of this application. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0051] This application provides a method for calibrating the DC branch current of an inverter to avoid the problem of inaccurate DC branch current detection results, while also avoiding increased system cost and maintenance difficulty.

[0052] For both centralized and string inverters, the DC side of their internal inverter circuits is connected to multiple branches. In centralized inverters, each branch connects to the output of a corresponding combiner box on the DC side of the inverter circuit. In string inverters, each branch connects to the output of a corresponding DC / DC converter circuit on the DC side of the inverter circuit. This embodiment provides a DC branch current calibration method applicable to both types of inverters, specifically including a branch calibration process performed on each branch of the DC side of the inverter circuit. See [link to documentation]. Figure 1 The branch calibration process includes:

[0053] S101. When a preset current value is injected into the corresponding branch, the current acquisition result is obtained.

[0054] In practical applications, the branch currently being calibrated can be connected to a test power supply, and current can be injected into this branch through the power supply. The magnitude of the injected current is a preset current value. In this case, the current of this branch can be detected by a corresponding current acquisition device, and then the corresponding current acquisition result can be transmitted to the inverter control system so that it can obtain the current acquisition result.

[0055] S102. Determine the relationship parameters between the current acquisition results and the preset current value.

[0056] In theory, the current acquisition result should be the same as the magnitude of the current injected into the branch, i.e., the preset current value. In reality, due to insufficient sampling accuracy of the branch current acquisition device, the current acquisition result may not be exactly the same as the preset current value. However, when the preset current value is different, the corresponding current detection result will also change. That is, there will be a certain correspondence between the two. This relationship can be expressed by relevant relational parameters. For example, in the simplest case, the difference between the two can be used as the relational parameter, but it is not limited to this.

[0057] S103. Store the relational parameters so that the inverter can correct the actual current acquisition results of the corresponding branch when actually connected to the grid.

[0058] When the inverter is actually connected to the grid, the actual current acquisition results obtained by the current acquisition devices of each branch will also have a certain difference from the true current value. This difference will be consistent with the correspondence between the current acquisition results and the preset current value during calibration testing. Therefore, the actual current acquisition results can be corrected by using the above-mentioned stored relationship parameters to restore them and make them closer to the true current value.

[0059] The above branch calibration process enables the current acquisition calibration of one branch on the DC side of the inverter circuit. When the inverter leaves the factory, the above branch calibration process can be performed on each branch separately to achieve automatic calibration of the current acquisition of each branch on the DC side of the inverter circuit in advance. A series of calculated relationship parameters for correction are saved. When the inverter is actually connected to the grid, the saved relationship parameters are automatically called first to correct the current acquisition results of the branch in real time, which ensures the accuracy of the branch current acquisition and reduces operation and maintenance costs.

[0060] The DC branch current calibration method provided in this embodiment, based on the aforementioned principle, obtains and stores the relationship parameters between the actual and collected values ​​of each branch current. When the inverter is actually connected to the grid, these relationship parameters can be invoked to correct the actual current collection results of the corresponding branch. Subsequently, the corrected branch current can be used for fault diagnosis and power generation control, avoiding the subsequent impacts caused by the low accuracy of current detection in existing technologies. Moreover, the entire process can be implemented solely through software, making it easy to implement without the need for additional high-precision current acquisition devices, thus avoiding increased system costs and maintenance difficulties.

[0061] Based on the previous embodiment, this embodiment provides some specific examples of the DC branch current calibration method. For example, during the branch calibration process, S101, when a preset current value is injected into the corresponding branch, the current acquisition result is obtained. Specifically, this may include: when the corresponding branch is injected with a current of different preset current values ​​at least twice, the corresponding current acquisition results are obtained respectively.

[0062] In practical applications, after the corresponding branch is connected to the power supply, a preset current value A1 can be injected into it through the power supply. At this time, a corresponding current will appear on the branch. The current acquisition device on the branch outputs the current acquisition result A_branch1 to the processor in the inverter control system, such as DSP (Digital Signal Processor). After receiving the corresponding current acquisition result A_branch1, the DSP sends it to an embedded intelligent control processing unit through communication, so that the embedded intelligent control processing unit can obtain the current acquisition result A_branch1.

[0063] However After that, The embedded intelligent control processing unit can save the preset current value A1 and the current acquisition result A_branch1; then, it injects another preset current value A2 into the branch through the power supply to obtain the corresponding current acquisition result A_branch2, and saves the preset current value A2 and the current acquisition result A_branch2; after n injections, multiple sets of data (A_branch) can be obtained. i A i ) are stored, where i = 1, 2, ..., n.

[0064] Furthermore, in the branch calibration process, S102 determines the relationship parameters between the current acquisition results and the preset current values. Specifically, this may include: performing linear fitting based on each preset current value and the corresponding current acquisition results to determine the relationship parameters.

[0065] Furthermore, when performing linear fitting, it can be based on the least squares method.

[0066] In this way, multiple sets of data (A_branch) can be processed. i A i While saving the data, the average value (M, N) of these multiple sets of data is calculated and saved. Then, a least squares method is used for fitting, and the fitted relationship function is: Y = kX + b, where X is the current acquisition result, Y is the preset current value, and k and b are linear coefficients, specifically calculated according to the following formula:

[0067]

[0068] b = N - kM

[0069] Then, the linear coefficients k and b can be used as the parameters of the above relationship.

[0070] Compared to a single current injection and acquisition, this embodiment improves the correction accuracy by injecting and acquiring current multiple times and fitting multiple sets of data, thereby improving the accuracy of current correction during actual grid connection.

[0071] This embodiment uses linear fitting as a specific example for detailed description. However, in practical applications, other methods can also be used for fitting, and it is not limited to the above form. It depends on the specific application environment. Any scheme that can obtain the correspondence between the preset current value and the current acquisition result is within the protection scope of this application.

[0072] Based on the above embodiments, this embodiment provides some more preferred specific examples of the DC branch current calibration method, for example, see [link to example]. Figure 2 During the calibration process of this branch, after determining the relationship parameters between the current acquisition results and the preset current value in S102, the following further steps are included:

[0073] S201. When the test current value is injected into the corresponding branch, the test acquisition result of its current is obtained.

[0074] That is, the test current value B is injected into the branch circuit, and then the test acquisition result B_branch of the corresponding branch current is obtained and transmitted to the embedded intelligent control processing unit.

[0075] S202. Verify the test current value and test acquisition results using relational parameters.

[0076] Specifically, S202 may include:

[0077] (1) Substitute either the test current value or the test acquisition result into the relational function of the relational parameters.

[0078] (2) Determine whether the absolute value of the difference between the test current value and another of the test acquisition results and the calculated result after substitution exceeds the preset accuracy threshold.

[0079] For example, when S102 is specifically based on least squares fitting, the embedded intelligent control processing unit can use the test acquisition result B_branch as X, substitute it into the relational function Y = kX + b, and obtain the corresponding calculation result Y. Then, it judges the absolute value of the difference between this calculation result Y and the test current value B; if the absolute value does not exceed the preset accuracy threshold, the verification is considered successful, and S103 can be executed. After completing the branch calibration process for the current branch, the branch calibration process for the next branch can begin; if the absolute value exceeds the preset accuracy threshold, the verification is considered unsuccessful, and it returns to S101 to continue injecting current, adding data, and correcting the above linear coefficients k and b in real time until the verification is successful. Only then is S103 executed to complete the branch calibration process for the current branch, and the branch calibration process for the next branch can begin.

[0080] In practical applications, the test current value B can also be used as Y, and substituted into the relational function Y = kX + b to obtain the corresponding calculation result X; then the absolute value of the difference between this calculation result X and the test acquisition result B_branch can be determined; moreover, when making the judgment, the value of the preset accuracy threshold can be determined according to the actual application environment, and no limitation is made here.

[0081] As can be seen from the above analysis, the re-injection of current in S201 is to determine whether the relationship parameters obtained through S101 and S102 can be successfully calibrated. Through the above verification process in S202, the calibration accuracy can be further improved, ensuring that the final relationship parameters can accurately characterize the correspondence between the actual value and the collected value of the branch current, thus ensuring successful calibration.

[0082] It is worth noting that the DC branch current calibration method can be performed by calibrating each branch separately in sequence or by calibrating each branch simultaneously, depending on the specific application environment, and both are within the scope of protection of this application.

[0083] The following explanation uses the example of performing branch calibration on each branch in sequence. Specifically, this process may include... Figure 3 As shown:

[0084] S301: Assign registers to each branch to store calibration identifier codes.

[0085] The initial value of the calibration identifier code for each branch is 0.

[0086] S302. Read the calibration identification code of each branch in sequence.

[0087] S303. After each reading, if the calibration identifier code of the current branch is 0, perform the branch calibration process, and set its calibration identifier code to 1 after the branch calibration process is completed, until the calibration identifier code of each branch is 1.

[0088] The branch calibration process specifically includes: Figure 1 or Figure 2 S101 to S103 shown in the figure will not be described again here.

[0089] For example, we can let i = i + 1, with i initially set to 1, and then read the current branch. i The calibration identifier code. If the current branch i If the calibration identifier is 1, then return to the step of setting i = i + 1, and read the current branch again. i The calibration identifier code; if the current branch i If the calibration identifier code is 0, then for the current branch i Perform the branch calibration process. Then, after the branch calibration process is complete, set its calibration flag to 1. Determine if i = n is true; if not, return to the step of setting i = i + 1 and read the current branch again. i The calibration identifier code is used to perform the branch calibration process; if it is valid, the DC branch current calibration method ends.

[0090] Of course, in practical applications, S302 and S303 are not limited to the above method of i taking values ​​from 1 to n. As long as it can be ensured that each branch can complete the corresponding current acquisition and calibration.

[0091] In addition, in this DC branch current calibration method, before performing the branch calibration process for each branch, a start calibration command can be received first, and then S301 to S303 can be executed; that is, the embedded intelligent control processing unit is triggered by receiving the start calibration command, and then starts to collect and calibrate the current of each branch.

[0092] It is worth noting that when the inverter is actually connected to the grid, after correcting the actual current acquisition results of each branch, it can also output the corrected acquisition results and visualize the calibrated current of each branch through the corresponding equipment. At the same time, it can also be forwarded to the corresponding actual backend. This depends on the specific application environment and is not limited here.

[0093] Another embodiment of this application also provides an inverter, see [link to relevant documentation] Figure 4 Specifically, it includes: a control system 10, an inverter circuit 30, and at least one current acquisition device 20; wherein:

[0094] The inverter circuit 30 has at least one branch connected to its DC side; in practical applications, each branch can be connected to multiple DC sources through a corresponding combiner box. These DC sources can be photovoltaic strings, in which case the inverter is a centralized inverter; alternatively, the inverter may also include... Figure 5 The inverter 30 shown in the figure is a string inverter. Each branch of the inverter circuit 30 on the DC side is connected to at least one corresponding DC source through the corresponding DC / DC conversion circuit 40.

[0095] The current acquisition device 20 is used to acquire the current of the corresponding branch and generate the corresponding current acquisition result to output to the control system 10; the current acquisition device 20 can be a current sensor, but is not limited to this.

[0096] The inverter circuit 30 is controlled by the control system 10. When the inverter includes a DC / DC conversion circuit 40, the DC / DC conversion circuit 40 is also controlled by the control system 10.

[0097] The control system 10 is used to execute the DC branch current calibration method for the inverter as described in any of the above embodiments. The specific process and principle of the DC branch current calibration method can be found in the above embodiments, and will not be repeated here.

[0098] This DC branch current calibration method enables the inverter to automatically calibrate the current of each branch on the production line before it leaves the factory. It is low-cost, easy to operate, and reduces on-site maintenance and rectification costs.

[0099] In practical applications, the control system 10 may specifically include Figure 6 (in order to be in) Figure 4 As shown in the example (based on the above), the processor 101 and the embedded intelligent control processing unit 102 are used to receive the current acquisition results output by each current acquisition device 20 and transmit them to the embedded intelligent control processing unit 102; the embedded intelligent control processing unit 102 is used to execute the DC branch current calibration method.

[0100] In practical applications, operators can directly enable the calibration by opening the calibration enable switch on the webpage or in the background of the embedded intelligent control processing unit 102, and issue a calibration start command to the embedded intelligent control processing unit 102. This causes the embedded intelligent control processing unit 102 to initiate the current calibration function for each branch according to the relevant command, entering a calibration ready state. A corresponding register is assigned to each branch to store the calibration identifier; a value of 1 indicates successful branch calibration, while a value of 0 indicates no calibration and the branch needs to be calibrated. Furthermore, the calibration identifiers for each branch are initially 0. Then, the embedded intelligent control processing unit 102 sequentially reads the register values ​​of each calibration identifier. If the value is 0, the branch is calibrated, i.e., the branch calibration process described in the above embodiment is executed. If the value is 1, the branch is skipped, and the register values ​​of other branch calibration identifiers are read until all branch calibration identifier register values ​​are 1, indicating that all branches have been calibrated, and the calibration process ends. After all branches have been calibrated, the calibration enable switch can be turned off.

[0101] This embodiment establishes a communication connection between the embedded intelligent control processing unit 102 and the processor 101. The processor 101 acquires and processes the current acquisition signals of each branch, and performs intelligent calculations on the relevant data to achieve intelligent correction and calibration of the current in each branch. This allows the inverter to be automatically calibrated in advance at the factory. The embedded intelligent control processing unit 102 calculates a series of relational parameters and saves them. When the inverter is actually connected to the grid, the embedded intelligent control processing unit 102 will automatically use the saved relational parameters to correct the branch current in real time, ensuring the accuracy of the branch current and reducing maintenance costs. Moreover, the corrected branch current can be displayed through an embedded web interface and transmitted to the corresponding backend.

[0102] Furthermore, this branch current calibration scheme is easy to implement and offers high calibration accuracy, solving the problem of deviations in branch current acquisition values ​​caused by insufficient accuracy of hardware branch current acquisition devices in existing technologies. It saves on the cost of replacing components with higher-precision ones and improves product quality.

[0103] Similar or identical parts between the various embodiments in this specification 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.

[0104] Those skilled in the art will further 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 implementations should not be considered beyond the scope of this invention.

[0105] The features described above regarding the disclosed embodiments can be substituted for or combined with each other to enable those skilled in the art to implement or use the invention. 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 the invention. Therefore, the invention 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 method for calibrating the DC branch current of an inverter, characterized in that, The inverter control system includes a processor and an embedded intelligent control processing unit communicatively connected to the processor. The method includes a branch calibration process performed separately for each branch of the DC side of the inverter circuit when a calibration enable switch is turned on. The branch calibration process includes: When a preset current value is injected into the corresponding branch, the embedded intelligent control processing unit acquires the current acquisition result. The current acquisition result is received by the processor and forwarded to the embedded intelligent control processing unit. The embedded intelligent control processing unit determines the relationship parameter between the current acquisition result and the preset current value. The embedded intelligent control processing unit acquires the test acquisition results of the current when the corresponding branch is injected with the test current value. The embedded intelligent control processing unit substitutes either the test current value or the test acquisition result into the relational function of the relational parameters; The embedded intelligent control processing unit determines whether the absolute value of the difference between the test current value and another of the test acquisition results and the calculated result after substitution exceeds a preset accuracy threshold. If the absolute value does not exceed the preset accuracy threshold, the verification is deemed successful, and the relationship parameter is stored so that the embedded intelligent control processing unit can correct the actual current acquisition result of the corresponding branch when the inverter is actually connected to the grid. If the absolute value exceeds the preset accuracy threshold, the verification is deemed unsuccessful, and current is injected to increase data and the relationship parameter is corrected in real time until the verification is successful. The embedded intelligent control processing unit sets the calibration identifier of its branch to 1 after the branch calibration process is completed; When the embedded intelligent control processing unit performs the branch calibration process for each branch, the embedded intelligent control processing unit is in the calibration working state, and allocates a corresponding register to each branch to store the calibration identifier. The initial value of the calibration identifier of each branch is 0. The embedded intelligent control processing unit sequentially reads the register values ​​of each calibration identifier; After each read, if the register value of the calibration identifier of the current branch is 0, the embedded intelligent control processing unit performs the branch calibration process; if the register value of the calibration identifier of the current branch is 1, it skips the current branch and continues to read the register values ​​of the calibration identifiers of other branches until the register values ​​of all branch calibration identifiers are 1.

2. The DC branch current calibration method for an inverter according to claim 1, characterized in that, When a preset current value is injected into the corresponding branch, the embedded intelligent control processing unit acquires the current acquisition results, including: The embedded intelligent control processing unit acquires the corresponding current acquisition results when the corresponding branch is injected with different preset current values ​​at least twice.

3. The DC branch current calibration method for an inverter according to claim 2, characterized in that, The embedded intelligent control processing unit determines the relationship parameters between the current acquisition results and the preset current value, including: The embedded intelligent control processing unit determines the relationship parameters by performing linear fitting based on each preset current value and the corresponding current acquisition results.

4. The DC branch current calibration method for an inverter according to claim 3, characterized in that, When performing linear fitting, the fitting is specifically based on the least squares method.

5. The DC branch current calibration method for an inverter according to any one of claims 1 to 4, characterized in that, When the embedded intelligent control processing unit performs the branch calibration process for each branch, specifically, the embedded intelligent control processing unit performs the branch calibration process for each branch in sequence.

6. The DC branch current calibration method for an inverter according to any one of claims 1 to 4, characterized in that, Before performing the branch calibration process on each branch, the embedded intelligent control processing unit further includes: The embedded intelligent control processing unit receives the start calibration command.

7. The DC branch current calibration method for an inverter according to any one of claims 1 to 4, characterized in that, When the inverter is actually connected to the grid, after the embedded intelligent control processing unit corrects the actual current acquisition results of each branch, it also includes: outputting the corrected acquisition results.

8. An inverter, characterized in that, include: The system comprises a control system, an inverter circuit, and at least one current acquisition device; wherein, The inverter circuit has at least one branch connected to its DC side; The current acquisition device is used to acquire the current of the corresponding branch and generate corresponding current acquisition results to be output to the control system. The inverter circuit is controlled by the control system, which is used to perform the DC branch current calibration method of the inverter as described in any one of claims 1 to 7.

9. The inverter according to claim 8, characterized in that, The control system includes: a processor and an embedded intelligent control processing unit; wherein... The processor is used to receive each of the current acquisition results and forward them to the embedded intelligent control processing unit; The embedded intelligent control processing unit is used to execute the DC branch current calibration method.

10. The inverter according to claim 8 or 9, characterized in that, Also includes: The DC / DC converter circuits connected to each branch.

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