Current compensation method for three-phase inverter, three-phase inverter and storage medium

Abstract

The application provides a current compensation method of a three-phase inverter, which comprises the following steps: obtaining the counter-current power error of each phase of the three-phase inverter; for each phase of the three-phase inverter, taking the phase as a target phase, determining a compensation value adjustment amplitude according to the counter-current power error of the target phase; adjusting a preset compensation value according to the compensation value adjustment amplitude to obtain an adjusted compensation value; compensating the given current of the target phase according to the adjusted compensation value to obtain a compensated given current; and performing current control on the target phase according to the compensated given current. Through the above method, the power in and out of each grid-connected point of the three-phase inverter can be stabilized to approach 0 in the phase-independent anti-counter-current scene of unbalanced load.

Description

Technical Field

[0001] This application belongs to the field of power generation technology, and in particular relates to a current compensation method for a three-phase inverter, a three-phase inverter, and a computer-readable storage medium. Background Technology

[0003] When a three-phase energy storage inverter is activated with independent phase reverse current protection (to adapt to unbalanced loads), ideally, the inverter power of each phase matches the load power in real time, ensuring that there is no power input or output (power is 0) for each phase at the grid connection point. However, in practical applications, power acquisition at the grid connection point involves two methods: meter communication and CT (Current Transformer) sampling and calculation. Both methods have sampling deviations, which, combined with small load control deviations, prevent the inverter power from achieving accurate and stable steady-state / dynamic response when directly controlling the inverter power through the grid connection point power. Consequently, the power of each phase at the grid connection point cannot remain at 0. Summary of the Invention

[0004] In view of this, this application provides a current compensation method for a three-phase inverter, a three-phase inverter, and a computer-readable storage medium, which enables the power input and output of each phase grid connection point of the three-phase inverter to be stably close to 0 in the scenario of independent anti-reverse current for unbalanced load.

[0005] In a first aspect, this application provides a current compensation method for a three-phase inverter, wherein the three-phase inverter is operating under a phase-independent anti-reverse current condition, the method comprising: Obtain the reverse power error of each phase of the three-phase inverter; For each phase of the three-phase inverter, taking that phase as the target phase, the adjustment range of the compensation value is determined based on the reverse power error of the target phase; The preset compensation value is adjusted according to the compensation value adjustment range to obtain the adjusted compensation value; The given current of the target phase is compensated according to the adjusted compensation value to obtain the compensated given current; The target phase is current controlled based on the compensated given current.

[0006] Secondly, this application provides a three-phase inverter, including a memory and a processor. The memory stores a computer program, and the processor is used to call and run the computer program from the memory, so that the three-phase inverter performs the method provided in the first aspect above.

[0007] Thirdly, this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method provided in the first aspect.

[0008] Fourthly, this application provides a computer program product that, when running on a three-phase inverter, causes the three-phase inverter to perform the method provided in the first aspect above.

[0009] In the current compensation method for a three-phase inverter provided in the first aspect above, the reverse power error of each phase of the three-phase inverter is obtained; for each phase of the three-phase inverter, taking that phase as the target phase, the adjustment range of the compensation value is determined according to the reverse power error of the target phase; the preset compensation value is adjusted according to the adjustment range of the compensation value to obtain the adjusted compensation value; the given current of the target phase is compensated according to the adjusted compensation value to obtain the compensated given current; and the current of the target phase is controlled according to the compensated given current. Thus, this solution obtains the reverse power error of each phase of the three-phase inverter independently, and matches the corresponding compensation value adjustment range for each phase separately, achieving completely independent compensation control for the three phases, avoiding coupling interference between phase controls, and adapting to the actual operating conditions where the errors of each phase are inconsistent under unbalanced loads. This method dynamically adjusts the compensation value based on the real-time reverse power error of each phase, which can accurately match the real-time sampling deviation and control deviation of each phase, avoiding over-adjustment and under-adjustment problems caused by fixed compensation or uniform adjustment, and avoiding frequent fluctuations in grid-connected power. The adjusted compensation value is directly applied to the given current of the corresponding phase, and then phase-by-phase current control is performed based on the compensated given current. This eliminates the lag of conventional power outer loop regulation, accelerates the deviation convergence speed, and stably achieves the anti-reverse current control target of making the power of each phase at the grid connection point approach zero.

[0010] It is understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this application, 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 some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a flowchart illustrating the current compensation method for a three-phase inverter provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a three-phase inverter provided in the embodiments of this application. Detailed Implementation

[0013] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0014] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0015] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0016] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrases "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0017] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0018] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0019] First, the technical terms mentioned in the embodiments of this application will be explained.

[0020] A three-phase inverter is a power converter primarily used to convert direct current (DC) power into alternating current (AC) power. Its operating principle is based on power electronics technology and control principles; through effective circuit design and adjustment, it achieves the DC-to-AC conversion.

[0021] Grid connection: Grid connection refers to connecting the power generated by the three-phase inverter to the mains power grid, enabling both to jointly supply power to the load or feed power back to the grid. During grid connection, the three-phase inverter needs to ensure that its output voltage, frequency, and phase match the mains power grid.

[0022] Reverse flow: Under the condition of prohibition of grid connection, the system should not have any power interaction with the public power grid. The electricity generated by photovoltaic and battery can only be used to supply the on-site load and charge the battery. Once more electricity is generated and less electricity is used, the excess electricity that is not consumed will "flow back" into the grid. This process is called reverse flow.

[0023] Phase-independent anti-reverse current: This refers to the inverter independently controlling the reverse current of each of the three phases (R, S, and T) to adapt to actual operating conditions with unbalanced three-phase loads. Simply put, the three-phase loads on the grid side often have inconsistent power (for example, phase A drives household appliances, phase B drives lighting, and phase C drives motors, with different load power in each phase). In phase-independent anti-reverse current mode, the inverter will detect the power flow direction at the grid connection point of each phase individually and then independently adjust the inverter output power of each phase, so that the inverter power of each phase is precisely matched to the load power of the corresponding phase.

[0024] In grid-connected applications of three-phase energy storage inverters, the three-phase loads on the grid side are often in an unbalanced operating state, meaning there are significant differences in the load power of the R, S, and T phases. To meet the grid connection specifications that prohibit inverter power from flowing back into the grid, and to adapt to the operating conditions of unbalanced three-phase loads, the three-phase energy storage inverter needs to enable the phase-independent anti-reverse flow control mode.

[0025] In the phase-independent anti-reverse flow control mode, the core control objective of the system is to perform independent power closed-loop control on the three phases R, S, and T respectively, so that the inverter power of each phase matches the load power consumption of that phase in real time, thereby ensuring that the power input and output of each phase at the grid connection point is always 0, neither absorbing power from the grid nor feeding inverter power to the grid.

[0026] However, in practical engineering applications, directly controlling inverter power through grid connection point power cannot achieve the aforementioned precise and stable steady-state response and excellent dynamic response. Consequently, it cannot guarantee that the power of each phase at the grid connection point will remain stably at zero. This is because the power data at the grid connection point is obtained through two main methods: one is reading the metered power data through the communication interface of the grid connection meter; the other is calculating the real-time power by sampling the real-time current at the grid connection point using a current transformer (CT) and combining it with the grid connection point voltage. Both methods have sampling errors. Furthermore, when the inverter is operating under light or low load conditions, the system will experience inherent low-load control deviations due to the increased proportion of power device conduction losses and switching losses, the reduced signal-to-noise ratio of current sampling, and the decreased tracking accuracy of the control loop.

[0027] The above-mentioned sampling deviation and the small load control deviation are superimposed on each other. When the grid connection point power data is directly used for closed-loop control, the grid connection point power will fluctuate frequently.

[0028] Figure 1 A flowchart of a current compensation method for a three-phase inverter according to an embodiment of this application is shown. This current compensation method is applied to a three-phase inverter, and the method is described in detail below: Step 101: Obtain the reverse power error of each phase of the three-phase inverter.

[0029] Step 102: For each phase of the three-phase inverter, take that phase as the target phase and determine the compensation value adjustment range based on the reverse power error of the target phase.

[0030] Step 103: Adjust the preset compensation value according to the compensation value adjustment range to obtain the adjusted compensation value.

[0031] Step 104: Compensate the given current of the target phase according to the adjusted compensation value to obtain the compensated given current.

[0032] Step 105: Perform current control on the target phase based on the compensated given current.

[0033] This method is applied to a three-phase inverter operating under independent phase anti-reverse current conditions. This three-phase inverter is a grid-connected three-phase energy storage inverter, suitable for grid-connected operation scenarios with unbalanced three-phase loads. Reverse current power error refers to the real-time calculated power value of the corresponding phase at the grid connection point of the three-phase inverter, used to characterize the power flow direction and degree of power deviation for that phase. A positive power value indicates a forward flow state, meaning the load power of that phase is greater than the inverter power, requiring power to be drawn from the grid; a negative power value indicates a reverse flow state, meaning the inverter power of that phase is greater than the load power, posing a risk of power feeding back to the grid. In this embodiment, independent power data acquisition and processing are performed on the R, S, and T phases of the three-phase inverter to obtain the reverse current power error for each phase.

[0034] It should be noted that the target phase refers to the single phase currently performing compensation control operation. All three phases (R, S, and T) of the three-phase inverter will serve as target phases to achieve completely independent decoupling control of the three phases. The compensation value adjustment range refers to the incremental value used to adjust the preset compensation value, matching the adjustment requirements of the current reverse current power error. Based on the real-time reverse current power error of the target phase, a compensation value adjustment range corresponding to the error amplitude is matched, achieving an adaptation between the error magnitude and the adjustment intensity, avoiding over-adjustment or under-adjustment problems caused by a fixed adjustment range. Simultaneously, each of the three phases independently determines its corresponding compensation value adjustment range without interference, allowing for precise response to the independent deviation of each phase.

[0035] In this embodiment, the preset compensation value refers to the reference value used for current compensation obtained after the adjustment in the previous control cycle, which can be set to 0 initially. The adjusted compensation value refers to the final value used for current compensation in this control cycle after correction by the adjustment range of the current compensation value. Based on the compensation value adjustment range determined in step 102, the compensation value is adjusted incrementally so that the compensation value can be dynamically updated with the reverse power error of the target phase, and can offset the sampling deviation and control deviation of the target phase in real time.

[0036] The given current refers to the reference current command value of the inner loop (closed-loop control) of the three-phase inverter, used to determine the inverter power of the corresponding phase. The compensated given current refers to the final current command value after adjustment and compensation, which is directly used for subsequent current closed-loop control. By directly applying the adjusted compensation value to the given current of the target phase, the inherent deviation between the sampling and control loops can be directly offset, eliminating the lag of conventional power outer loop closed-loop regulation and accelerating the deviation convergence speed. Using the compensated given current as the closed-loop control reference, the inverter current closed-loop tracking control is performed on the target phase, ensuring that the actual output current of the three-phase inverter tracks the compensated given current in real time, thus guaranteeing that the power of the target phase at the grid connection point is stably maintained within the anti-reverse current requirement range.

[0037] It should be understood that the goal of the inverter control inner loop is to enable the actual output current of the corresponding phase of the three-phase inverter to track the compensated given current in real time, ultimately achieving precise regulation of the inverter power. The closed-loop control (inverter control inner loop) adopts a negative feedback regulation architecture and uses a PI (proportional-integral) regulator to achieve tracking.

[0038] In some embodiments, determining the adjustment range of the compensation value based on the reverse power error of the target phase includes: From multiple preset error intervals, determine the target error interval in which the reverse power error of the target phase is located; Determine the adjustment range of the compensation value corresponding to the target error range.

[0039] In this embodiment, multiple non-overlapping error intervals are pre-set, and each error interval is pre-matched with a corresponding compensation value adjustment range. All error intervals fully cover the full range of reverse power error values. The number of error intervals, the interval boundary values, and the magnitude of the corresponding compensation value adjustment range can all be flexibly configured according to the actual situation of the three-phase inverter, and no restrictions are imposed here.

[0040] After obtaining the reverse current power error of the target phase in the current control cycle, the value of this reverse current power error is compared with all preset error intervals to locate the error interval into which the value falls; this interval is the target error interval. Once the target error interval is determined, the corresponding compensation value adjustment range is directly retrieved; this value is the final adjustment range used for compensation value adjustment in the current control cycle. In this way, through this interval division and matching method, corresponding compensation value adjustment ranges can be matched for reverse current power errors of different magnitudes. This avoids frequent adjustments under small errors and speeds up the adjustment process under large errors.

[0041] The following detailed explanation, using a specific example, clarifies the division of error intervals and the matching method for compensation value adjustment amplitudes: A compensation stop power point (StopPowerPoint) and a switching step point (SwitchPowerPoint) are pre-set. Using these two thresholds as boundaries, multiple continuous and non-overlapping preset error intervals are defined. Each preset error interval is matched with a corresponding compensation value adjustment amplitude. The value of the compensation stop power point can be flexibly configured according to the method of obtaining the reverse current power: when the reverse current power is obtained through communication with the meter, the compensation stop power point is set to P; when the reverse current power is obtained through CT sampling, the compensation stop power point is set to 4P. P can be a pre-set steady-state control dead zone reference value for phase-independent anti-reverse current control.

[0042] The matching relationship between the preset error range and the corresponding compensation value adjustment range is as follows: When the reverse power error is within the error range of (-StopPowerPoint, StopPowerPoint), the corresponding compensation value adjustment range is 0, that is, no compensation value adjustment is performed. When the reverse power error is within the error range of (StopPowerPoint, SwitchPowerPoint), the corresponding compensation value adjustment range is -1, that is, the compensation value is reduced by 1. When the reverse power error is greater than SwitchPowerPoint, the corresponding compensation value adjustment range for this range is -3, that is, the compensation value is reduced by 3. When the reverse power error is within the error range of (-SwitchPowerPoint, -StopPowerPoint), the corresponding compensation value adjustment range is +1, that is, the compensation value is increased by 1. When the reverse power error is less than - SwitchPowerPoint, the corresponding compensation value adjustment range for this range is +3, that is, the compensation value is increased by 3.

[0043] Optionally, adjusting the preset compensation value according to the compensation value adjustment range to obtain the adjusted compensation value includes: The adjusted compensation value is obtained by summing the preset compensation value and the adjustment range of the compensation value.

[0044] In this embodiment of the application, the sum of a preset compensation value and the compensation value adjustment range is calculated, and the adjusted compensation value is determined based on the sum.

[0045] Specifically, when the three-phase inverter is initially powered on or when the phase-independent anti-reverse current control function is activated, the preset compensation value is set to 0 by default. The positive or negative attribute of the compensation value adjustment range directly determines the adjustment direction: when the compensation value adjustment range is positive, the calculated sum is greater than the preset compensation value, and the compensation value is adjusted upward; when the compensation value adjustment range is negative, the calculated sum is less than the preset compensation value, and the compensation value is adjusted downward. This adjustment method ensures that the change in compensation value within each control cycle matches the current reverse current power error of the target phase, avoiding numerical jumps caused by full replacement of the compensation value, ensuring a smooth and continuous adjustment process, and thus preventing sudden changes in the given current of the target phase of the inverter, preventing large fluctuations in inverter power. At the same time, this adjustment method can follow the real-time reverse current power error of the target phase, continuously iteratively updating the compensation value of the corresponding phase, offsetting the inherent deviations between the sampling and control loops in real time, and continuously ensuring the steady-state accuracy of the anti-reverse current control.

[0046] Optionally, obtaining the adjusted compensation value based on the sum of the preset compensation value and the compensation value adjustment range includes: If the sum is between a preset upper limit for compensation and a preset lower limit for compensation, then the sum is determined as the adjusted compensation value. If the sum is greater than the compensation limit, then the compensation limit is determined as the adjusted compensation value; If the sum is less than the lower compensation limit, then the lower compensation limit is determined as the adjusted compensation value.

[0047] In this embodiment, the adjusted compensation value is determined based on the sum of a preset compensation value and the compensation value adjustment range. During execution, the calculated sum can be limited to constrain the reasonable adjustment range of the compensation value. For example, a compensation upper limit and a compensation lower limit are preset, where the compensation upper limit is MAXCompensate and the compensation lower limit is -MAXCompensate. The specific values ​​can be flexibly configured according to the actual situation of the inverter.

[0048] If the calculated sum is between the preset upper and lower compensation limits, this sum is directly determined as the adjusted compensation value. If the calculated sum is greater than the preset upper compensation limit, it means that the calculated compensation value exceeds the maximum allowable positive compensation range, and the upper compensation limit is determined as the adjusted compensation value. If the calculated sum is less than the preset lower compensation limit, it means that the calculated compensation value exceeds the maximum allowable negative compensation range, and the lower compensation limit is determined as the adjusted compensation value. This ensures that the adjusted compensation value of each phase of the three-phase inverter is always within the range of [-MAXCompensate, MAXCompensate], avoiding excessive adjustment of the compensation value under extreme operating conditions and preventing inverter output power overshoot. Simultaneously, using uniform upper and lower compensation limits for the three phases ensures that the adjustment range of the compensation values ​​for the three phases is consistent, avoiding severe imbalance in the three-phase output caused by excessive differences in the compensation values ​​of each phase.

[0049] In some embodiments, the step of compensating the given current of the target phase according to the adjusted compensation value to obtain the compensated given current includes: According to the preset formula, the adjusted compensation value is superimposed on the given current of the target phase to obtain the compensated given current. The preset formula is I'=I*K+R, where I' is the compensated given current, I is the given current, K represents the proportion of the target reverse current power of the target phase to the total three-phase inverter power, and R is the adjusted compensation value.

[0050] In this process, for each of the three phases of the three-phase inverter, the currently processed phase is taken as the target phase. The compensation calculation for the given current is completed using a preset formula, and the adjusted compensation value is superimposed on the given current of the target phase to obtain the finally compensated given current. Compared with the conventional control method of adjusting the current command through the power outer loop closed loop, this method of directly superimposing the adjusted compensation value can eliminate the lag caused by the power outer loop adjustment.

[0051] Optionally, K is equal to the ratio of the target reverse current power of the target phase to the total inverter power of the three phases multiplied by S%, where S is a preset reverse current adjustment slope. The method further includes increasing the compensation speed by increasing S.

[0052] In this embodiment, S is a pre-set reverse current regulation slope, which is an adjustable parameter that can be flexibly calibrated according to the actual situation of the three-phase inverter. By adjusting the value of the reverse current regulation slope S, the amplification factor of the proportional coefficient K can be changed, thereby adjusting the regulation amplitude of the target phase given current, and ultimately changing the dynamic adjustment speed of the reverse current power error. When it is necessary to improve the dynamic adjustment speed, the value of S can be appropriately increased, and the corresponding value of S% increases synchronously. The calculated K value is amplified accordingly, and the current regulation amplitude of the target phase increases synchronously. When facing conditions such as sudden load changes and sudden changes in reverse current power error, the amplified K value can accelerate the convergence speed of the target phase power deviation and shorten the time for reverse current elimination.

[0053] Optionally, obtaining the reverse power error of each phase of the three-phase inverter includes: The reverse current power of each phase of the three-phase inverter is obtained by communicating with the electricity meter, or by CT sampling. The reverse power of each phase is averaged and filtered to obtain the reverse power error of each phase.

[0054] In this embodiment, the three-phase inverter can establish a communication connection with the grid-connected meter at the grid connection point to directly read the reverse current power of each phase corresponding to the grid connection point, as output by the meter. Alternatively, the three-phase inverter can collect real-time AC current data of each phase at the grid connection point through a current transformer (CT) located at the grid connection point, and simultaneously collect real-time AC voltage data of the corresponding phase. The reverse current power of each phase is obtained by multiplying the real-time AC current data and real-time AC voltage data. Then, independent mean filtering is performed on the reverse current power of each phase of the three-phase inverter. The power data output after mean filtering is the reverse current power error of the corresponding phase of the three-phase inverter.

[0055] As can be seen from the above, in this application, the reverse current power error of each phase of the three-phase inverter is obtained independently, and the corresponding compensation value adjustment range is matched separately for each phase, realizing completely independent compensation control of the three phases. This avoids coupling interference between phase control and adapts to the actual operating conditions where the errors of each phase are inconsistent under unbalanced loads. Based on the real-time reverse current power error of each phase, the compensation value of this application is dynamically adjusted, which can accurately match the real-time sampling deviation and control deviation of each phase, avoiding over-adjustment and under-adjustment problems caused by fixed compensation or uniform adjustment, and avoiding frequent fluctuations in power at the grid connection point. The adjusted compensation value is directly applied to the given current of the corresponding phase, and then phase-by-phase current control is performed based on the compensated given current. This eliminates the lag of conventional power outer loop regulation, accelerates the deviation convergence speed, and stably achieves the anti-reverse current control target of the power of each phase approaching zero at the grid connection point.

[0056] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0057] Figure 2 This is a schematic diagram of a three-phase inverter provided in one embodiment of this application. Figure 2 As shown, the three-phase inverter 2 in this embodiment includes: at least one processor 20 ( Figure 2 The three-phase inverter executes the current compensation method described above when the processor 20 executes the computer program 22, which is stored in the memory 21 and can run on at least one processor 20.

[0058] The aforementioned three-phase inverter 2 may include, but is not limited to, a processor 20 and a memory 21. Those skilled in the art will understand that... Figure 2 This is merely an example of a three-phase inverter 2 and does not constitute a limitation on the three-phase inverter 2. It may include more or fewer components than shown in the figure, or combine certain components, or different components, such as input / output devices, network access devices, etc.

[0059] The processor 20 may be a Central Processing Unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0060] In some embodiments, the aforementioned memory 21 may be an internal storage unit of the three-phase inverter 2, such as a hard disk or memory of the three-phase inverter 2. In other embodiments, the aforementioned memory 21 may be an external storage device of the three-phase inverter 2, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the three-phase inverter 2. Furthermore, the aforementioned memory 21 may include both internal storage units and external storage devices of the three-phase inverter 2. The aforementioned memory 21 is used to store operating systems, application programs, bootloaders, data, and other programs, such as the program code of the aforementioned computer programs. The aforementioned memory 21 may also be used to temporarily store data that has been output or will be output.

[0061] It should be noted that the information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0062] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the above device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0063] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps in the various method embodiments described above.

[0064] This application provides a computer program product that, when run on a three-phase inverter, causes the three-phase inverter to execute the steps described in the various method embodiments above.

[0065] If the integrated units described above are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include at least: any entity or device capable of carrying computer program code to a three-phase inverter, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electrical carrier signals or telecommunication signals.

[0066] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0067] Those skilled in the art will 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, or a combination of computer software and electronic hardware. 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 application.

[0068] In the embodiments provided in this application, it should be understood that the disclosed apparatus / network devices and methods can be implemented in other ways. For example, the apparatus / network device embodiments described above are merely illustrative. For instance, the division of modules or units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0069] The units described above 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 units can be selected to achieve the purpose of this embodiment according to actual needs.

[0070] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A current compensation method for a three-phase inverter, characterized in that, The three-phase inverter is operating under a phase-independent anti-reverse current condition, and the method includes: Obtain the reverse power error of each phase of the three-phase inverter; For each phase of the three-phase inverter, taking that phase as the target phase, the adjustment range of the compensation value is determined based on the reverse power error of the target phase; The preset compensation value is adjusted according to the compensation value adjustment range to obtain the adjusted compensation value; The given current of the target phase is compensated according to the adjusted compensation value to obtain the compensated given current; The target phase is current controlled based on the compensated given current.

2. The method as described in claim 1, characterized in that, The step of determining the adjustment range of the compensation value based on the reverse power error of the target phase includes: From multiple preset error intervals, determine the target error interval in which the reverse power error of the target phase is located; Determine the adjustment range of the compensation value corresponding to the target error range.

3. The method as described in claim 1, characterized in that, The step of adjusting the preset compensation value according to the adjustment range of the compensation value to obtain the adjusted compensation value includes: The adjusted compensation value is obtained by summing the preset compensation value and the adjustment range of the compensation value.

4. The method as described in claim 3, characterized in that, The step of obtaining the adjusted compensation value based on the sum of the preset compensation value and the adjustment range of the compensation value includes: If the sum is between a preset upper limit for compensation and a preset lower limit for compensation, then the sum is determined as the adjusted compensation value. If the sum is greater than the compensation limit, then the compensation limit is determined as the adjusted compensation value; If the sum is less than the lower compensation limit, then the lower compensation limit is determined as the adjusted compensation value.

5. The method as described in claim 1, characterized in that, The step of compensating the given current of the target phase according to the adjusted compensation value to obtain the compensated given current includes: According to the preset formula, the adjusted compensation value is superimposed on the given current of the target phase to obtain the compensated given current. The preset formula is I'=I*K+R, where I' is the compensated given current, I is the given current, K represents the proportion of the target reverse current power of the target phase to the total three-phase inverter power, and R is the adjusted compensation value.

6. The method as described in claim 5, characterized in that, K is equal to the ratio of the target reverse current power of the target phase to the total inverter power of the three phases multiplied by S%, where S is the preset reverse current adjustment slope.

7. The method as described in claim 6, characterized in that, The method also includes increasing the compensation speed by increasing S.

8. The method as described in claim 1, characterized in that, The process of obtaining the reverse power error of each phase of the three-phase inverter includes: The reverse current power of each phase of the three-phase inverter is obtained by communicating with the electricity meter, or by CT sampling. The reverse power of each phase is averaged and filtered to obtain the reverse power error of each phase.

9. A three-phase inverter, characterized in that, The device includes a memory and a processor, wherein the memory stores a computer program, and the processor is configured to call and run the computer program from the memory, causing the three-phase inverter to perform the method as described in any one of claims 1-8.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1 to 8.

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