Off-grid control method for energy storage converter

Abstract

The invention provides an off-grid control method for energy storage converters, which comprises the following steps: in response to operation of a plurality of energy storage converters in a parallel mode in an off-grid mode, configuring the plurality of energy storage converters to a master-slave distributed control architecture, and by adopting the master-slave distributed control architecture, taking a first energy storage converter as a master control unit, and taking a second energy storage converter as a slave control unit; the reference current is determined according to the real-time output voltage, the average current is calculated in combination with the real-time output current of each second energy storage converter, and then the compensation current is determined to perform current sharing operation on the energy storage converters, so that each energy storage converter can distribute power according to a reasonable proportion. The situation that part of the energy storage converters are overloaded and part of the energy storage converters are overloaded due to uneven power distribution is avoided, and the stability and reliability of the whole energy storage system are improved. The current sharing control is carried out by calculating the compensation current, so that the circulating current between the energy storage converters in parallel operation can be effectively inhibited, unnecessary energy loss is reduced, and the operation efficiency and safety of the whole energy storage system are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of energy storage design and application, and particularly relates to a method for off-grid control of an energy storage converter. BACKGROUND

[0002] As the central device of micro-grid energy conversion and control, a power conversion system (PCS) undertakes three major functions of bidirectional power flow, providing energy support when there is no power grid, and multi-machine collaborative control, but in actual application, it faces the defect of difficulty in power regulation.

[0003] It should be noted that the above introduction to the technical background is only for the convenience of clearly and completely describing the technical scheme of the present application, and facilitating the understanding of those skilled in the art. The above technical scheme cannot be considered as known to those skilled in the art merely because it is described in the background section of the present application. SUMMARY

[0004] The purpose of the present application is to at least solve one of the technical problems in the related art to some extent.

[0005] To this end, the first purpose of the present application is to provide a method for off-grid control of an energy storage converter.

[0006] The second purpose of the present application is to provide an off-grid control device for an energy storage converter.

[0007] The third purpose of the present application is to provide an electronic device.

[0008] The fourth purpose of the present application is to provide a non-transitory computer readable storage medium.

[0009] The fifth purpose of the present application is to provide a computer program product.

[0010] To achieve the above purpose, the first aspect of the present application provides a method for off-grid control of an energy storage converter, comprising:

[0011] In response to multiple energy storage converters operating in parallel in an off-grid mode, the multiple energy storage converters are configured as a master-slave distributed control architecture, including a first energy storage converter as a master control unit and at least one second energy storage converter as a slave control unit;

[0012] determining a reference current according to a real-time output voltage of the first energy storage converter;

[0013] determining an average current according to real-time output currents of the first energy storage converter and each second energy storage converter;

[0014] A compensation current is determined according to the reference current and the average current, wherein the compensation current is used to perform a current sharing operation on the first energy storage converter and each of the second energy storage converters.

[0015] To achieve the above-mentioned objectives, a second embodiment of the present application proposes an off-grid control device for an energy storage converter, comprising:

[0016] a configuration module configured to configure the plurality of energy storage converters into a master-slave distributed control architecture in response to the plurality of energy storage converters operating in parallel in an off-grid mode, including a first energy storage converter as a master control unit and at least one second energy storage converter as a slave control unit;

[0017] a first acquisition module, configured to determine a reference current according to a real-time output voltage of the first energy storage converter;

[0018] A second acquisition module, the second acquisition module being configured to determine an average current according to the real-time output currents of the first energy storage converter and each of the second energy storage converters;

[0019] A control module is used to determine a compensation current according to the reference current and the average current, wherein the compensation current is used to perform a current sharing operation on the first energy storage converter and each of the second energy storage converters.

[0020] To achieve the above-mentioned purpose, the third aspect embodiment of the present application proposes an electronic device, comprising: a processor; a memory for storing instructions executable by the processor; wherein the processor is configured to execute the instructions to implement the off-grid control method of the energy storage converter proposed in the first aspect embodiment of the present application.

[0021] To achieve the above-mentioned purpose, the fourth embodiment of the present application proposes a non-temporary computer-readable storage medium. When the instructions in the storage medium are executed by the processor of an electronic device, the electronic device is able to execute the off-grid control method of the energy storage inverter proposed in the first embodiment of the present application.

[0022] To achieve the above-mentioned purpose, the fifth embodiment of the present application proposes a computer program product, including a computer program, which, when executed by a processor in a communication device, implements the off-grid control method of the energy storage converter proposed in the first embodiment of the present application.

[0023] In an embodiment of the present application, when multiple energy storage converters are operated in parallel in an off-grid mode, a master-slave distributed control architecture is adopted, with the first energy storage converter being the main control unit, a reference current is determined according to the real-time output voltage, and the average current is calculated in combination with the real-time output current of each second energy storage converter, and then a compensation current is determined to perform a current balancing operation on the energy storage converter, so that each energy storage converter can distribute power in a reasonable proportion, avoiding the situation where some energy storage converters are overloaded and some energy storage converters are underloaded due to uneven power distribution, thereby improving the stability and reliability of the entire energy storage system. By calculating the compensation current for current balancing control, the circulating current between the energy storage converters operating in parallel can be effectively suppressed, unnecessary energy loss can be reduced, and the operating efficiency and safety of the entire energy storage system can be improved.

[0024] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0026] Figure 1 A flow chart of an off-grid control method for an energy storage converter provided in an embodiment of the present application;

[0027] Figure 2 A schematic diagram of the structure of an energy storage converter operating in parallel provided in an embodiment of the present application;

[0028] Figure 3 A schematic diagram of a distributed control architecture according to an embodiment of the present application is provided;

[0029] Figure 4 A schematic diagram of a parallel equivalent model of an energy storage converter provided according to an embodiment of the present application;

[0030] Figure 5 A flow chart of another off-grid control method for an energy storage converter provided in an embodiment of the present application;

[0031] Figure 6 A schematic structural diagram of an off-grid control device for an energy storage converter provided in an embodiment of the present application;

[0032] Figure 7 The figure is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0033] Exemplary embodiments are described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numbers in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible implementations consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with certain aspects of the present invention, as detailed in the appended claims.

[0034] The terms used in the embodiments of this application are for the purpose of describing specific embodiments only and are not intended to limit the embodiments of this application. The singular forms "a" and "the" used in the embodiments of this application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0035] It should be understood that although the terms first, second, third, etc. may be used to describe various information in the embodiments of the present application, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of the embodiments of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if" and "if" as used herein may be interpreted as "at the time of" or "when" or "in response to a determination."

[0036] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0037] The Power Conversion System (PCS) is a core device for microgrids, enabling efficient energy conversion and precise control. During microgrid operation, the PCS flexibly converts power from direct current (DC) to alternating current (AC) and vice versa, tailored to the grid's needs.

[0038] When the power generation of distributed power sources (such as solar photovoltaic, wind power, etc.) in the microgrid is greater than the current load demand, the energy storage inverter will quickly store the excess electricity in the form of DC into the energy storage device (such as a battery), realizing the "absorption" and storage of electricity; and when the distributed power generation is insufficient or the load demand increases, it can promptly convert the DC power stored in the energy storage device into AC power, providing stable power support for the load, ensuring that the power supply and demand of the microgrid is always in a dynamic balance.

[0039] When a microgrid is disconnected from the main grid and enters off-grid operation, the energy storage inverter becomes a key pillar for ensuring a stable power supply. At this point, through precise control algorithms and a rapid response mechanism, the energy storage inverter can monitor the microgrid's load changes in real time and rapidly adjust its output power accordingly, ensuring that the voltage and frequency on the AC side remain within specified ranges. For example, when a high-power load suddenly enters the microgrid, the energy storage inverter immediately increases its output power to prevent a drop in voltage and frequency. Conversely, when the load decreases, it reduces its output power accordingly to avoid excessive voltage and frequency fluctuations.

[0040] However, despite the crucial role and significant advantages of energy storage converters in microgrids, they also face the daunting challenge of power regulation in practical applications. For one thing, the distributed power sources in microgrids are intermittent and fluctuating, and their output power is significantly affected by natural factors such as weather, light intensity, and wind speed. This necessitates that the energy storage converter quickly and accurately adjust its power output based on the real-time changes in the distributed power sources to maintain stable microgrid operation. However, this frequent power adjustment requires the energy storage converter to possess extremely high response speed and dynamic performance; otherwise, the voltage and frequency of the microgrid may fluctuate, impacting the normal operation of the load.

[0041] Therefore, how to solve these difficulties faced by energy storage converters in power regulation has become one of the important directions of current microgrid technology research.

[0042] The following describes an off-grid control method and device for an energy storage converter according to an embodiment of the present application with reference to the accompanying drawings.

[0043] Figure 1 A flow chart of an off-grid control method for an energy storage converter provided in an embodiment of the present application.

[0044] like Figure 1 As shown, the method includes but is not limited to the following steps:

[0045] S101 , in response to multiple energy storage converters operating in an off-grid mode in parallel, configure the multiple energy storage converters into a master-slave distributed control architecture, including a first energy storage converter as a master control unit and at least one second energy storage converter as a slave control unit.

[0046] In a feasible implementation, in off-grid mode, a single energy storage converter is limited by the capacity of its internal power devices and is therefore unable to meet the needs of a megawatt-class energy storage power station.

[0047] For example, power devices such as IGBTs and SiC-MOSFETs have on-resistance and device area that directly determine their maximum allowable current. When the current exceeds the rated value of the power device, it can lead to overheating, damage, or even breakdown. For example, the rated current of an IGBT may only be a few hundred amperes, while an energy storage converter requires current handling capabilities of thousands of amperes, which cannot be achieved with a single IGBT.

[0048] For example, the voltage rating of a power device (e.g., 600V, 1200V, 1700V) limits the maximum voltage it can withstand. In high-voltage scenarios (such as grid-level energy storage), a single energy storage converter must handle voltages of several thousand volts, necessitating voltage division by connecting multiple power devices in series. However, this connection can lead to voltage balancing, which can easily cause uneven voltage distribution across the power devices, potentially damaging some due to excessive voltage.

[0049] As an example, the switching frequency of power devices can affect the efficiency and size of energy storage converters. For example, when the switching frequency of power devices is increased, the magnetic flux requirements of magnetic components such as inductors and transformers within the energy storage converter decrease (magnetic flux is inversely proportional to frequency), thereby allowing the use of smaller magnetic cores and reducing the size of the energy storage converter. However, increasing the switching frequency of power devices increases switching losses, causing excessive temperature rise in the power devices, requiring increased heat dissipation to control the temperature. Increasing heat dissipation will increase the size of the energy storage converter.

[0050] For example, in order to break through the power limitation of a single energy storage converter, multiple energy storage converters can be used in parallel to operate in off-grid mode. Figure 2 A schematic diagram of a structure of an energy storage converter operating in parallel provided in an embodiment of the present application is shown in FIG. Figure 2 As shown in Figure 1, connecting multiple energy storage converters in parallel can achieve redundancy and improve the availability of the microgrid system. In charging mode, the energy storage converter rectifies AC power into DC power, charging the energy storage power supply according to the instructions of the battery management system (BMS) within the energy storage power supply. In discharging mode, the energy storage power supply outputs DC power, which the energy storage converter inverts into AC power, and then powers the load through AC power.

[0051] In a feasible implementation, multiple energy storage converters operating in parallel can build a stable and reliable microgrid system to provide continuous power support, and the multiple energy storage converters operating in parallel are configured as a master-slave distributed control architecture. Figure 3 A schematic diagram of a parallel equivalent model of an energy storage converter provided according to an embodiment of the present application is shown in FIG. Figure 3 As shown, by designating the first energy storage converter as the master control unit and the remaining second energy storage converters as slave control units, the energy storage converters can work together to ensure that the microgrid system operates stably and meets load requirements.

[0052] In some embodiments, as Figure 3 As shown, the first energy storage converter is responsible for coordinating the power distribution of each second energy storage converter. Based on the load demand and the rated power and health status of each second energy storage converter, the active and reactive power tasks are rationally allocated to ensure that each second energy storage converter operates in a safe and efficient manner, avoiding overload or long-term underload conditions.

[0053] In some embodiments, as Figure 3 As shown, the first energy storage converter can monitor the operating status of each second energy storage converter in real time. Once an abnormal situation is detected (such as overcurrent, overvoltage, undervoltage, overtemperature, etc.), the first energy storage converter will immediately take corresponding protection measures, such as issuing an alarm signal, adjusting power output, isolating faulty equipment, etc.

[0054] In some embodiments, as Figure 3 As shown, the first energy storage converter communicates with each second energy storage converter and the upper-level monitoring device via the CAN bus. When multiple energy storage converters operate in parallel, power distribution imbalance and circulating current problems can easily occur due to factors such as parameter differences between converters and line impedance mismatch.

[0055] For example, Figure 4 A schematic diagram of a parallel equivalent model of an energy storage converter provided according to an embodiment of the present application is shown in FIG. Figure 4 As shown, there are two energy storage converters connected in parallel. The energy storage converter is equivalent to a voltage source and an impedance in series, where the energy storage converter PCS1 is equivalent to a current source E1 and an impedance Z1 in series, and the energy storage converter PCS2 is equivalent to a current source E2 and an impedance Z2 in series. The load is equivalent to the impedance Z0. The energy storage converter PCS1 outputs active power P1 and reactive power Q1, and the energy storage converter PCS2 outputs active power P2 and reactive power Q2. The energy storage converter PCS1 outputs current I1, and the energy storage converter PCS2 outputs current I2, which is represented by I h Indicates circulation. U pcc represents the voltage at the common connection point,

[0056] like Figure 4 As shown, according to the circuit principle, the expressions of current I1 and current I2 are:

[0057]

[0058] If the current I1 and the current I2 are not equal, the circulating current I h , circulation I h The expression is:

[0059]

[0060] It should be noted that uneven power distribution will cause some converters to be in an overloaded operating state for a long time, shortening their service life; while circulating current will increase the system's reactive loss, reduce energy utilization efficiency, and may even cause system failure.

[0061] In some embodiments, as Figure 3 As shown, CAN-A is the data communication link that performs current balancing control. In the CAN-A link, each secondary energy storage converter transmits its output current data to the primary energy storage converter in real time according to a predetermined control cycle (e.g., a pulse width modulation control cycle). After receiving this data, the primary energy storage converter calculates the current sharing control data for each secondary energy storage converter and transmits this data back to each secondary energy storage converter, ensuring balanced current distribution when multiple converters operate in parallel.

[0062] In some embodiments, as Figure 3 As shown, CAN-B is a logical communication channel responsible for real-time feedback and coordinated control of the operating status of each energy storage converter. The second energy storage converter continuously feeds back its current operating status information to the first energy storage converter via CAN-B. After obtaining this status information, the first energy storage converter issues corresponding control instructions to each second energy storage converter based on a preset logical control strategy, thereby achieving precise coordination and optimized control of the operating status of each second energy storage converter.

[0063] In some embodiments, as Figure 3 As shown, high-frequency synchronization signal control is used to provide carrier synchronization. The power devices within the energy storage converter are typically switched on and off by a PWM (Pulse Width Modulation) carrier. The first energy storage converter issues a synchronization instruction, which is transmitted to each second energy storage converter via a high-frequency synchronization signal control line. After receiving the synchronization instruction, the second energy storage converter performs synchronization operations within each PWM carrier cycle to ensure that the PWM carriers of each second energy storage converter are highly consistent when operating in parallel, thereby ensuring the stability and reliability of the power devices.

[0064] In some embodiments, as Figure 3 As shown, the low-frequency synchronization signal is used to achieve phase synchronization within each power frequency cycle. The first energy storage converter issues a synchronization command, which is transmitted to each secondary energy storage converter via the low-frequency synchronization signal control line. After receiving the synchronization command, the secondary energy storage converter completes phase synchronization once within each power frequency cycle to ensure that the phases of the secondary energy storage converters remain consistent when operating in parallel, avoiding power oscillations and efficiency reduction caused by phase differences.

[0065] S102: Determine a reference current according to the real-time output voltage of the first energy storage converter.

[0066] In one feasible embodiment, voltage amplitude control is employed to determine the reference current based on the real-time output voltage. A voltage deviation is determined based on the rated voltage amplitude of the first energy storage converter and the real-time output voltage amplitude. Proportional resonance is performed on the voltage deviation to obtain an amplitude correction component and a phase correction component of the reference current. Based on the amplitude correction component and the phase correction component, a phase-locked loop is used to generate the reference current.

[0067] S103 : Determine an average current according to the real-time output currents of the first energy storage converter and each second energy storage converter.

[0068] In a feasible implementation manner, the real-time output currents of the first energy storage converter and each of the second energy storage converters are arithmetic averaged or weighted averaged to obtain an average current.

[0069] In some embodiments, the power allocation coefficient of each second energy storage converter is determined by the first energy storage converter. The real-time output current of each second energy storage converter is weighted according to the power allocation coefficient and combined with the real-time output current of the first energy storage converter to obtain an average current.

[0070] S104 , determining a compensation current according to the reference current and the average current, wherein the compensation current is used to perform a current sharing operation on the first energy storage converter and each second energy storage converter.

[0071] In one feasible implementation, a deviation between a reference current and an average current is obtained. The first energy storage converter distributes the deviation to all energy storage converters according to the power proportions of the first energy storage converter and each second energy storage converter, thereby obtaining compensation currents for the first energy storage converter and each second energy storage converter. The compensation currents are used to perform current sharing operations on the first energy storage converter and each second energy storage converter.

[0072] In summary, the off-grid control method for the energy storage converter provided in the embodiment of the present application, when multiple energy storage converters are operated in parallel in the off-grid mode, adopts a master-slave distributed control architecture, with the first energy storage converter as the main control unit, determines the reference current according to the real-time output voltage, and calculates the average current in combination with the real-time output current of each second energy storage converter, and then determines the compensation current to perform current balancing operation on the energy storage converter, so that each energy storage converter can distribute power in a reasonable proportion, avoiding the situation where some energy storage converters are overloaded and some energy storage converters are underloaded due to uneven power distribution, thereby improving the stability and reliability of the entire energy storage system. By calculating the compensation current for current balancing control, the circulating current between the energy storage converters operating in parallel can be effectively suppressed, unnecessary energy loss can be reduced, and the operating efficiency and safety of the entire energy storage system can be improved.

[0073] Figure 5 A flow chart of another off-grid control method for an energy storage converter provided in an embodiment of the present application.

[0074] like Figure 5 As shown, the method includes but is not limited to the following steps:

[0075] S501 , in response to multiple energy storage converters operating in an off-grid mode in parallel, configure the multiple energy storage converters into a master-slave distributed control architecture, including a first energy storage converter as a master control unit and at least one second energy storage converter as a slave control unit.

[0076] For further details on step S501, please refer to the relevant contents in the above embodiment, which will not be repeated here.

[0077] S502 : Determine a first reference current based on the d-axis and a second reference current based on the q-axis according to the three-phase real-time output voltage of the first energy storage converter.

[0078] In one feasible embodiment, the three-phase real-time output voltage of the first energy storage converter is obtained. Clark transform and Park transform are performed on the three-phase real-time output voltage to obtain a d-axis real-time output voltage and a q-axis real-time output voltage. A first reference current based on the d-axis is determined based on a preset d-axis reference voltage and the d-axis real-time output voltage. A second reference current based on the q-axis is determined based on a preset q-axis reference voltage and the q-axis real-time output voltage.

[0079] In some embodiments, a d-axis differential voltage between a preset d-axis reference voltage and a d-axis real-time output voltage is obtained, and proportional-integral regulation is performed on the d-axis differential voltage to obtain a first reference current.

[0080] In some embodiments, a q-axis differential voltage between a preset q-axis reference voltage and the q-axis real-time output voltage is obtained, and proportional-integral regulation is performed on the q-axis differential voltage to obtain a second reference current.

[0081] S503 : Determine a d-axis average current and a q-axis average current according to the three-phase real-time output currents of the first energy storage converter and each second energy storage converter.

[0082] In one feasible embodiment, a first three-phase real-time output current of the first energy storage converter and a second three-phase real-time output current of each second energy storage converter are obtained. Clark transform and Park transform are performed on the first three-phase real-time output current to obtain a first d-axis real-time output current and a first q-axis real-time output current. Clark transform and Park transform are performed on the second three-phase real-time output current to obtain a second d-axis real-time output current and a second q-axis real-time output current. A d-axis average current is determined based on the first d-axis real-time output current and the second d-axis real-time output current, and a q-axis average current is determined based on the first q-axis real-time output current and the second q-axis real-time output current.

[0083] For example, the d-axis average current is obtained by taking an arithmetic average or weighted average of the first d-axis real-time output current and the second d-axis real-time output current, and the q-axis average current is obtained by taking an arithmetic average or weighted average of the first q-axis real-time output current and the second q-axis real-time output current.

[0084] S504, determining a d-axis compensation current based on the first reference current and the d-axis average current, and determining a q-axis compensation current based on the second reference current and the q-axis average current, wherein the d-axis compensation current and the q-axis compensation current are used to perform current sharing operations on the first energy storage converter and each second energy storage converter.

[0085] In one feasible implementation, a d-axis differential current between a first reference current and a d-axis average current is determined; a proportional-integral adjustment is performed on the d-axis differential current to obtain a d-axis compensation current. A q-axis differential current between a second reference current and a q-axis average current is determined; a proportional-integral adjustment is performed on the q-axis differential current to obtain a q-axis compensation current.

[0086] As an example, the compensation operation performed by the d-axis compensation current and the q-axis compensation current reduces the difference between the first reference current and the d-axis average current, as well as the difference between the second reference current and the q-axis average current, until all energy storage converters achieve current sharing.

[0087] In summary, the off-grid control method for the energy storage converter provided in the embodiment of the present application, when multiple energy storage converters are operated in parallel in the off-grid mode, adopts a master-slave distributed control architecture, with the first energy storage converter as the main control unit, determines the reference current according to the real-time output voltage, and calculates the average current in combination with the real-time output current of each second energy storage converter, and then determines the compensation current to perform current balancing operation on the energy storage converter, so that each energy storage converter can distribute power in a reasonable proportion, avoiding the situation where some energy storage converters are overloaded and some energy storage converters are underloaded due to uneven power distribution, thereby improving the stability and reliability of the entire energy storage system. By calculating the compensation current for current balancing control, the circulating current between the energy storage converters operating in parallel can be effectively suppressed, unnecessary energy loss can be reduced, and the operating efficiency and safety of the entire energy storage system can be improved.

[0088] Figure 6 This is a schematic diagram of the structure of an off-grid control device for an energy storage converter provided in an embodiment of the present application. Figure 6 As shown, the energy storage converter off-grid control device 600 includes:

[0089] A configuration module 601 is configured to configure, in response to multiple energy storage converters operating in parallel in an off-grid mode, the multiple energy storage converters into a master-slave distributed control architecture, including a first energy storage converter as a master control unit and at least one second energy storage converter as a slave control unit;

[0090] A first acquisition module 602, the first acquisition module 602 is used to determine a reference current according to the real-time output voltage of the first energy storage converter;

[0091] A second acquisition module 603, the second acquisition module 603 is used to determine the average current according to the real-time output current of the first energy storage converter and each second energy storage converter;

[0092] The control module 604 is used to determine a compensation current according to the reference current and the average current, wherein the compensation current is used to perform a current sharing operation on the first energy storage converter and each second energy storage converter.

[0093] Figure 7 The figure is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present application. Figure 7 The electronic device shown is merely an example and should not limit the functions and scope of use of the embodiments of the present application.

[0094] like Figure 7As shown, the electronic device 700 includes a processor 701, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 702 or a program loaded from a memory 706 into a random access memory (RAM) 703. Various programs and data required for the operation of the electronic device 700 are also stored in the RAM 703. The processor 701, the ROM 702, and the RAM 703 are connected to each other via a bus 704. An input / output (I / O) interface 705 is also connected to the bus 704.

[0095] The following components are connected to the I / O interface 705: a memory 706 including a hard disk, etc.; and a communication part 707 including a network interface card such as a LAN (Local Area Network) card, a modem, etc., which performs communication processing via a network such as the Internet; a drive 708 is also connected to the I / O interface 705 as needed.

[0096] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program carried on a computer-readable medium, and the computer program includes program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network via the communication section 707. When the computer program is executed by the processor 701, the above-mentioned functions defined in the method of the present application are performed.

[0097] In an exemplary embodiment, a storage medium including instructions is further provided, such as a memory including instructions, and the instructions can be executed by the processor 701 of the electronic device 700 to perform the above method. Alternatively, the storage medium can be a non-transitory computer-readable storage medium, such as a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc.

[0098] In this application, a computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. Furthermore, in this application, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries computer-readable program code. This propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transfer a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wire, optical cable, RF, etc., or any suitable combination thereof.

[0099] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0100] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for controlling an off-grid energy storage converter, characterized in that: include: In response to a plurality of energy storage converters operating in an off-grid mode in parallel, configuring the plurality of energy storage converters into a master-slave distributed control architecture, including a first energy storage converter as a master control unit and at least one second energy storage converter as a slave control unit; Determining a reference current according to the real-time output voltage of the first energy storage converter; Determining an average current according to the real-time output currents of the first energy storage converter and each of the second energy storage converters; A compensation current is determined according to the reference current and the average current, wherein the compensation current is used to perform a current sharing operation on the first energy storage converter and each of the second energy storage converters.

2. The method according to claim 1, characterized in that The determining of the reference current according to the real-time output voltage of the first energy storage converter includes: A first reference current based on the d-axis and a second reference current based on the q-axis are determined according to the three-phase real-time output voltage of the first energy storage converter.

3. The method according to claim 2, characterized in that The determining, according to the three-phase real-time output voltage of the first energy storage converter, a first reference current based on the d-axis and a second reference current based on the q-axis includes: Obtaining the three-phase real-time output voltage of the first energy storage converter; Performing Clark transformation and Park transformation on the three-phase real-time output voltage to obtain a d-axis real-time output voltage and a q-axis real-time output voltage; A first reference current based on the d-axis is determined according to a preset d-axis reference voltage and the d-axis real-time output voltage, and a second reference current based on the q-axis is determined according to a preset q-axis reference voltage and the q-axis real-time output voltage.

4. The method according to claim 3, characterized in that The determining of a first reference current based on the d-axis according to a preset d-axis reference voltage and the d-axis real-time output voltage includes: Acquiring a d-axis differential voltage between a preset d-axis reference voltage and the d-axis real-time output voltage; Proportional-integral adjustment is performed on the d-axis differential voltage to obtain the first reference current.

5. The method according to claim 3, characterized in that The determining of the second reference current based on the q-axis according to the preset q-axis reference voltage and the q-axis real-time output voltage includes: Acquiring a q-axis differential voltage between a preset q-axis reference voltage and the q-axis real-time output voltage; Proportional-integral regulation is performed on the q-axis differential voltage to obtain the second reference current.

6. The method according to claim 1, characterized in that The determining the average current according to the real-time output current of the first energy storage converter and each of the second energy storage converters includes: The d-axis average current and the q-axis average current are determined according to the three-phase real-time output currents of the first energy storage converter and each of the second energy storage converters.

7. The method according to claim 6, characterized in that The determining of the d-axis average current and the q-axis average current according to the three-phase real-time output current of the first energy storage converter and each of the second energy storage converters includes: Obtaining a first three-phase real-time output current of the first energy storage converter and a second three-phase real-time output current of each of the second energy storage converters; Performing Clark transformation and Park transformation on the first three-phase real-time output current to obtain a first d-axis real-time output current and a first q-axis real-time output current; Performing Clark transformation and Park transformation on the second three-phase real-time output current to obtain a second d-axis real-time output current and a second q-axis real-time output current; A d-axis average current is determined according to the first d-axis real-time output current and the second d-axis real-time output current, and a q-axis average current is determined according to the first q-axis real-time output current and the second q-axis real-time output current.

8. The method according to claim 1, characterized in that The determining of the compensation current according to the reference current and the average current includes: The d-axis compensation current is determined according to the first reference current and the d-axis average current, and the q-axis compensation current is determined according to the second reference current and the q-axis average current.

9. The method according to claim 8, characterized in that The determining of the d-axis compensation current according to the first reference current and the d-axis average current includes: determining a d-axis differential current between the first reference current and the d-axis average current; Proportional-integral regulation is performed on the d-axis differential current to obtain a d-axis compensation current.

10. The method according to claim 8, characterized in that The determining of the q-axis compensation current according to the second reference current and the q-axis average current includes: determining a q-axis differential current between the second reference current and the q-axis average current; Proportional-integral regulation is performed on the q-axis differential current to obtain a q-axis compensation current.

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