Self-adaptive switching method and device for network construction mode and network following mode of energy storage converter, storage medium and electronic equipment

Abstract

The embodiment of the invention provides a self-adaptive switching method and device for a network construction mode and a network following mode of an energy storage converter, a storage medium and electronic equipment, and relates to the technical field of grid-connected control of the energy storage converter. Judging the strength of the power grid according to the output result of the primary frequency modulation function of the energy storage converter, and switching to a grid following mode when the strength of the power grid is high; and when the energy storage converter operates in the grid following mode, judging the strength of the power grid according to the variation of the voltage frequency and amplitude before and after the current regulation of the power grid, and switching to the grid construction mode when the strength of the power grid is weak. According to the technical scheme, the dependence on a power grid strength detection function can be weakened, reasonable self-adaptive switching can be realized under relatively simple algorithm complexity, and meanwhile, the requirement on MCU hardware is reduced.

Description

Technical Field

[0001] This application relates to the field of grid-connected control technology for energy storage converters, and more specifically, to a method, apparatus, storage medium, and electronic device for adaptive switching of grid-connected and grid-connected modes of an energy storage converter. Background Technology

[0002] With the high proportion of new energy sources leading to reduced grid system inertia and grid strength fluctuations (short-circuit ratio changes), energy storage converters require high-precision power control in strong grid scenarios (grid-following mode), while in weak grid scenarios they need enhanced stability and voltage and frequency support (grid-forming mode). Therefore, achieving adaptive switching between grid-forming (GFM) and grid-following (GFL) modes of energy storage converters is crucial for improving power system stability and promoting the consumption of new energy sources.

[0003] Grid strength is a core factor in grid construction and grid connection mode switching decisions, so energy storage converters need to have the function of detecting grid strength. Currently, there are two main detection methods: 1. Passive measurement, based on grid disturbances themselves; 2. Active measurement, where the energy storage converter actively injects disturbances.

[0004] Passive measurement only observes and does not affect the power grid, relying on natural grid disturbances, resulting in low accuracy. Active measurement, by injecting specific harmonics, can achieve more accurate detection results, but it carries the risk of exacerbating power grid instability. More importantly, analyzing grid strength significantly increases algorithm complexity and MCU resource requirements. Summary of the Invention

[0005] The embodiments of this application provide a method, apparatus, storage medium, and electronic device for adaptive switching between grid construction and grid-following modes of energy storage converters, in order to solve the problem that grid strength detection requires the introduction of complex algorithms and the consumption of more computing resources.

[0006] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0007] According to a first aspect of the embodiments of this application, a method for adaptive switching of energy storage converter network construction and grid connection modes is provided, including: When the energy storage converter is operating in grid-connected mode, the strength of the grid is judged based on the output of the primary frequency regulation function of the energy storage converter. When the grid strength is high, it switches to grid-following mode. When the energy storage converter operates in grid-connected mode, it judges the strength of the grid based on the changes in voltage frequency and amplitude before and after current regulation, and switches to grid-connected mode when the grid strength is weak.

[0008] In some embodiments of the present application, based on the foregoing solution, determining the strength of the power grid according to the output result of the primary frequency regulation function of the energy storage converter includes: Obtain the active power Po and reactive power Qo output by the primary frequency regulation function; Calculate the deviation value dPo between the active power Po and the set active power Pset, and calculate the deviation value dQo between the reactive power Qo and the set reactive power Qset; Compare the deviation value dPo and the deviation value dQo with the switching thresholds P and Q respectively. When dPo < P and dQo < Q, it is determined that the current power grid strength is relatively large.

[0009] In some embodiments of the present application, based on the foregoing solution, the switching thresholds P and the switching thresholds Q are set according to the grid strength networking requirements, specifically: P = Pn * x%; Q = Qn * x%; Where, Pn is the rated output active power of the energy storage converter, Qn is the rated output reactive power of the energy storage converter, and x is the primary frequency regulation output coefficient.

[0010] In some embodiments of the present application, based on the foregoing solution, determining the strength of the power grid according to the change amount of the voltage frequency and amplitude before and after the current regulation of the power grid includes: Record the effective value Vgrms of the power grid voltage and the frequency Vgf under no-load of the energy storage converter; Record the effective value Vgrms1 of the power grid voltage and the frequency Vgf1 before the energy storage converter adjusts the current Irms1; Record the effective value Vgrms2 of the power grid voltage and the frequency Vgf2 after the energy storage converter adjusts the current Irms2; Perform the following calculations: d2 = ABS((Vgf2 - Vgf1) * (Vgrms2 - Vgrms1) / (Irms2 - Irms1)) d1 = ABS((Vgf2 - Vgf) * (Vgrms2 - Vgrms) / (Irms2)); Compare d2 and d1 with the switching threshold d. When d2 > d or d1 > d, it is determined that the current power grid is relatively weak; Where, the switching threshold d is set according to the grid strength following requirements. The smaller d is, the stronger the power grid strength is required to operate in the following network mode.

[0011] In some embodiments of the present application, based on the foregoing solution, when setting the switching threshold d and the primary frequency regulation output coefficient x, it is necessary to make their corresponding grid strengths have a hysteresis loop.

[0012] According to a second aspect of the embodiments of this application, an adaptive switching device for grid-connected and grid-connected modes of an energy storage converter is provided, comprising: The first switching unit is used for: When the energy storage converter is operating in grid-connected mode, the strength of the grid is judged based on the output of the primary frequency regulation function of the energy storage converter. When the grid strength is high, it switches to grid-following mode. The second switching unit is used for: When the energy storage converter operates in grid-connected mode, it judges the strength of the grid based on the changes in voltage frequency and amplitude before and after current regulation, and switches to grid-connected mode when the grid strength is weak.

[0013] According to a third aspect of the embodiments of this application, a computer-readable storage medium is provided, the storage medium storing computer instructions that, when executed on a computer, cause the computer to perform the method as described in the first aspect.

[0014] According to a fourth aspect of the embodiments of this application, an electronic device is provided, including: a memory and a processor; The memory is used to store computer instructions; The processor is configured to invoke computer instructions stored in the memory, causing the electronic device to execute the method described in the first aspect.

[0015] The technical solution of this application does not rely directly on grid strength detection. It can achieve precise power control and power quality regulation when the grid is stable and the strength is sufficient. When the grid weakens, it can quickly support the grid voltage and frequency and improve the grid impedance characteristics.

[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings: Figure 1 A flowchart illustrating an adaptive switching method for grid-connected and grid-connected modes of an energy storage converter according to an embodiment of this application is shown. Figure 2 A block diagram of an energy storage converter grid construction and grid connection mode adaptive switching device according to an embodiment of this application is shown; Figure 3A block diagram of an electronic device according to one embodiment of this application is shown; Figure 4 A schematic diagram of the structure of a computer system suitable for implementing the electronic device of the present application is shown. Detailed Implementation

[0018] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0019] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0020] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0021] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such uses of these terms can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described.

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0024] The following detailed description of some embodiments of this application will be provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0025] To address the technical problems existing in the prior art, this application proposes an adaptive switching method for the grid construction and grid-connection modes of energy storage converters. The logic of this method is as follows: When the energy storage converter operates in grid-connected mode, the primary frequency regulation function in the grid-connected control algorithm will adjust the voltage amplitude and frequency of the grid towards the rated values. When the grid strength is weak, the active power and reactive power setpoints of the energy storage converter will have a large increment, thereby adjusting the active power and reactive power to support the grid voltage amplitude and frequency. When the grid is strong, the output adjustment of the primary frequency regulation is small and there is no need to support the grid. Therefore, in grid-connected mode, the energy storage converter can judge the strength of the grid by judging the output of the primary frequency regulation function. When the output adjustment is small, the grid strength is large, and it can switch to grid-connected mode operation.

[0026] When the energy storage converter operates in grid-connected mode, it tracks the commanded current as a current source. When the grid strength is low, as the output current increases, the frequency and amplitude of the grid voltage detected by the energy storage converter will deviate significantly from those before the current change. When the grid strength is high, even if the energy storage converter outputs a large current, the amplitude and frequency of the grid voltage change less. Therefore, by comparing the voltage amplitude and frequency before and after current regulation, it can be determined whether to operate in grid-connected mode.

[0027] For details, see Figure 1 The diagram shows a flowchart illustrating an adaptive switching method for grid-connected and grid-connected modes of an energy storage converter according to an embodiment of this application.

[0028] like Figure 1 As shown, an adaptive switching method for grid-connected and grid-following modes of energy storage converters is demonstrated, including steps S100 to S200.

[0029] refer to Figure 1 In step S100, when the energy storage converter is operating in grid-connected mode, the grid strength is determined based on the output result of the primary frequency regulation function of the energy storage converter, and the grid strength is switched to grid-connected mode when the grid strength is high.

[0030] In some feasible embodiments, based on the foregoing solution, determining the strength of the power grid according to the output result of the primary frequency regulation function of the energy storage converter includes: Obtain the active power Po and reactive power Qo output by the primary frequency regulation function; Calculate the deviation value dPo between the active power Po and the set active power Pset, and calculate the deviation value dQo between the reactive power Qo and the set reactive power Qset; Compare the deviation value dPo and the deviation value dQo with the switching threshold P and the switching threshold Q respectively. When dPo < P and dQo < Q, it is determined that the current power grid strength is relatively large.

[0031] That is, in this embodiment, when dPo < P and dQo < Q, the energy storage converter switches to the grid-following mode; otherwise, it remains in the grid-forming mode.

[0032] It should be noted that in this embodiment, the calculation formula of the deviation value dPo is as follows: dPo = Pset – Po; The calculation formula of the deviation value dQo is as follows: dQo = Qset – Qo.

[0033] In some feasible embodiments, based on the foregoing solution, the switching threshold P and the switching threshold Q are set according to the grid-forming requirements of the power grid strength. Specifically: P = Pn * x%; Q = Qn * x%; Where, Pn is the rated output active power of the energy storage converter, Qn is the rated output reactive power of the energy storage converter, and x is the primary frequency regulation output coefficient. The smaller x is, the stronger the power grid strength is required to operate in the grid-following mode.

[0034] Continue to refer to Figure 1 , step S200. When the energy storage converter is operating in the grid-following mode, determine the strength of the power grid according to the changes in the voltage frequency and amplitude before and after the current regulation of the power grid, and switch to the grid-forming mode when the power grid strength is weak.

[0035] In some feasible embodiments, based on the foregoing solution, determining the strength of the power grid according to the changes in the voltage frequency and amplitude before and after the current regulation of the power grid includes: Record the effective value Vgrms of the power grid voltage and the frequency Vgf under no-load of the energy storage converter; Record the effective value Vgrms1 of the power grid voltage and the frequency Vgf1 before the energy storage converter adjusts the current Irms1; Record the effective value of the grid voltage Vgrms2 and the frequency Vgf2 after the energy storage converter adjusts the current Irms2; Perform the following calculations: d2 =ABS( (Vgf2-Vgf1)*(Vgrms2-Vgrms1) / (Irms2-Irms1)) d1= ABS((Vgf2-Vgf)* (Vgrms2-Vgrms) / (Irms2)); Compare d2 and d1 with the switching threshold d. If d2>d or d1>d, the current power grid is determined to be weak. The switching threshold d is set according to the grid strength and grid demand. The smaller d is, the greater the grid strength is required for grid-connected mode to operate.

[0036] In this embodiment, when d2>d or d1>d, the energy storage converter operation mode is switched to grid-connected mode; otherwise, it remains in grid-connected mode.

[0037] In some feasible embodiments, based on the aforementioned scheme, when setting the switching threshold d and the primary frequency regulation output coefficient x, it is necessary to ensure that the corresponding grid strength has hysteresis.

[0038] It should be noted that, in this embodiment, the purpose of the above steps is to prevent switching between the two operating modes.

[0039] In summary, the adaptive switching method for grid-connected and grid-following modes of energy storage converters provided in this application can reduce the reliance on grid strength detection functions, achieve reasonable adaptive switching with relatively simple algorithm complexity, and reduce the requirements for MCU hardware.

[0040] The following describes an embodiment of the apparatus described in this application, which can be used to execute an adaptive switching method for grid-connected and grid-connected modes of an energy storage converter as described in the above embodiments of this application. For details not disclosed in the apparatus embodiments of this application, please refer to the embodiments of the method described in the above applications.

[0041] Reference Figure 2 As shown, an adaptive switching device 200 for grid-connected and grid-connected modes of an energy storage converter according to an embodiment of this application includes: The first switching unit 201 is used for: When the energy storage converter is operating in grid-connected mode, the strength of the grid is judged based on the output of the primary frequency regulation function of the energy storage converter. When the grid strength is high, it switches to grid-following mode. The second switching unit 202 is used for: When the energy storage converter operates in grid-connected mode, it judges the strength of the grid based on the changes in voltage frequency and amplitude before and after current regulation, and switches to grid-connected mode when the grid strength is weak.

[0042] like Figure 3 As shown, this application embodiment also provides an electronic device 300, including a memory 310, a processor 320, and a computer program 311 stored in the memory 310 and executable on the processor. When the processor 320 executes the computer program 311, it implements the steps of the above-mentioned adaptive switching method for grid construction and grid connection mode of an energy storage converter.

[0043] Since the electronic device described in this embodiment is the device used to implement the adaptive switching device for grid construction and grid connection mode of an energy storage converter in the embodiments of this application, those skilled in the art can understand the specific implementation method and various variations of the electronic device in this embodiment based on the method described in the embodiments of this application. Therefore, how the electronic device implements the method in the embodiments of this application will not be described in detail here. Any device used by those skilled in the art to implement the method in the embodiments of this application is within the scope of protection of this application.

[0044] In practice, when the computer program 311 is executed by the processor, it can implement any of the embodiments corresponding to the first aspect.

[0045] Figure 4 A schematic diagram of the structure of a computer system suitable for implementing the electronic device of the present application is shown.

[0046] It should be noted that, Figure 4 The computer system 400 of the electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0047] like Figure 4 As shown, the computer system 400 includes a Central Processing Unit (CPU) 401, which can perform various appropriate actions and processes based on programs stored in Read-Only Memory (ROM) 402 or programs loaded from storage portion 408 into Random Access Memory (RAM) 403, such as performing the methods described in the above embodiments. Various programs and data required for system operation are also stored in RAM 403. The CPU 401, ROM 402, and RAM 403 are interconnected via bus 404. An Input / Output (I / O) interface 405 is also connected to bus 404.

[0048] The following components are connected to I / O interface 405: an input section 406 including a keyboard, mouse, etc.; an output section 407 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and speakers, etc.; a storage section 408 including a hard disk, etc.; and a communication section 409 including a network interface card such as a LAN (Local Area Network) card, modem, etc. The communication section 409 performs communication processing via a network such as the Internet. A drive 410 is also connected to I / O interface 405 as needed. A removable medium 411, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 410 as needed so that computer programs read from it can be installed into storage section 408 as needed.

[0049] Specifically, according to embodiments of this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 409, and / or installed from removable medium 411. When the computer program is executed by central processing unit (CPU) 401, it performs various functions defined in the system of this application.

[0050] It should be noted that the computer-readable medium shown in the embodiments of this application can be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, portable compact disc read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such transmitted data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to wireless, wired, etc., or any suitable combination thereof.

[0051] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. Each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0052] The units described in the embodiments of this application can be implemented in software or hardware, and the described units can also be located in a processor. The names of these units do not necessarily limit the specific unit itself.

[0053] In another aspect, this application also provides a computer program product or computer program including computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the adaptive switching method for grid-connected and grid-linked modes of an energy storage converter as described in the above embodiments.

[0054] In another aspect, this application also provides a computer-readable medium, which may be included in the electronic device described in the above embodiments; or it may exist independently and not assembled into the electronic device. The computer-readable medium carries one or more programs, which, when executed by the electronic device, cause the electronic device to implement the adaptive switching method for grid-connected and grid-linked modes of an energy storage converter as described in the above embodiments.

[0055] It should be noted that although several modules or units for the device used to perform actions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to the embodiments of this application, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0056] Through the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solutions according to the embodiments of this application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, touch terminal, or network device, etc.) to execute the methods according to the embodiments of this application.

[0057] Other embodiments of this application will readily conceive of by those skilled in the art upon consideration of the specification and practice of the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. It should be understood that this application is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for adaptive switching between grid-connected and grid-connected modes of an energy storage converter, characterized in that, include: When the energy storage converter is operating in grid-connected mode, the strength of the grid is judged based on the output of the primary frequency regulation function of the energy storage converter. When the grid strength is high, it switches to grid-following mode. When the energy storage converter operates in grid-connected mode, it judges the strength of the grid based on the changes in voltage frequency and amplitude before and after current regulation, and switches to grid-connected mode when the grid strength is weak.

2. The method according to claim 1, characterized in that, The method of determining the grid strength based on the output of the primary frequency regulation function of the energy storage converter includes: Obtain the active power Po and reactive power Qo output by the primary frequency regulation function; Calculate the deviation dPo between active power Po and set active power Pset, and calculate the deviation dQo between reactive power Qo and set reactive power Qset; The deviation values ​​dPo and dQo are compared with the switching thresholds P and Q, respectively. When dPo < P and dQo < Q, it is determined that the current power grid strength is relatively high.

3. The method according to claim 2, characterized in that, The switching threshold P and the switching threshold Q are set according to the grid strength requirements, specifically as follows: P = Pn*x%; Q = Qn*x% Where Pn is the rated output active power of the energy storage converter, Qn is the rated output reactive power of the energy storage converter, and x is the primary frequency regulation output coefficient.

4. The method according to claim 3, characterized in that, The method of judging the strength of the power grid based on the changes in voltage frequency and amplitude before and after current regulation includes: Record the effective value of the grid voltage Vgrms and the frequency Vgf of the energy storage converter under no-load conditions; Record the effective value of the grid voltage Vgrms1 and the frequency Vgf1 before the energy storage converter adjusts the current Irms1; Record the effective value of the grid voltage Vgrms2 and the frequency Vgf2 after the energy storage converter adjusts the current Irms2; Perform the following calculations: d2 =ABS( (Vgf2-Vgf1)*(Vgrms2-Vgrms1) / (Irms2-Irms1)) d1= ABS((Vgf2-Vgf)* (Vgrms2-Vgrms) / (Irms2)); Compare d2 and d1 with the switching threshold d. If d2 > d or d1 > d, the current power grid is determined to be weak. The switching threshold d is set according to the grid strength and grid demand. The smaller d is, the greater the grid strength is required for grid-connected mode to operate.

5. The method according to claim 4, characterized in that, When setting the switching threshold d and the primary frequency regulation output coefficient x, it is necessary to ensure that the corresponding grid strength has hysteresis.

6. An adaptive switching device for grid-connected and grid-connected modes of an energy storage converter, characterized in that, include: The first switching unit is used for: When the energy storage converter is operating in grid-connected mode, the strength of the power grid is judged based on the output of the primary frequency regulation function of the energy storage converter. When the power grid strength is high, it switches to grid-following mode. The second switching unit is used for: When the energy storage converter operates in grid-connected mode, it judges the strength of the power grid based on the changes in voltage frequency and amplitude before and after current regulation, and switches to grid-connected mode when the power grid strength is weak.

7. A computer-readable storage medium, characterized in that, The storage medium stores computer instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 1-5.

8. An electronic device, characterized in that, include: Memory and processor; The memory is used to store computer instructions; The processor is configured to invoke computer instructions stored in the memory, causing the electronic device to perform the method as described in any one of claims 1-5.

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