Black start control method, energy storage converter, energy storage system and related apparatus

Abstract

The present application provides a black start control method, an energy storage converter, an energy storage system and a related apparatus. The black start control method is applied to at least one of a plurality of energy storage converters connected in parallel in an energy storage system, the method comprising: when a black start control instruction is received, on the basis of a target frequency and a frequency droop control term, determining the output frequency of an active power loop in the energy storage system; on the basis of a target voltage, a voltage droop control term and a voltage compensation term, determining the output voltage of a reactive power loop in the energy storage system; and, on the basis of the output frequency of the active power loop in the energy storage system and the output voltage of the reactive power loop in the energy storage system, determining an output voltage reference value used for implementing black start of the energy storage converters, so as to control the output power of the energy storage converters. The present application can improve the consistency and simultaneity of multi-machine control, and ensure successful black start of the energy storage system comprising multiple machines connected in parallel.

Description

Black start control method, energy storage converter, energy storage system and related devices

[0001] This application claims priority to Chinese patent application No. 202510205700.2, filed on February 24, 2025, entitled "Black Start Control Method, Energy Storage Converter, Energy Storage System and Related Devices", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of black-start technology for energy storage systems, and in particular to black-start control methods, energy storage converters, energy storage systems and related devices. Background Technology

[0003] Energy storage systems are characterized by rapid response and hourly output, meeting the requirements for black start after system failure. Large-capacity energy storage systems are generally composed of multiple energy storage units connected in parallel. During black start off-grid operation, the power conversion systems (PCS) in the energy storage units are typically connected in parallel using voltage source modes such as droop or VSG (Virtual Synchronous Generator). However, parallel operation is prone to a series of problems such as oscillation, circulating current, and uneven power distribution. Black start of multiple parallel energy storage converters places high demands on the consistency and simultaneity of multi-machine control, making it difficult to successfully achieve black start of multi-machine parallel energy storage systems. Summary of the Invention

[0004] The purpose of this application is to provide a black start control method, an energy storage converter, an energy storage system and related devices to improve the consistency and simultaneity of multi-machine control and ensure that the energy storage system with multiple machines in parallel can be successfully black started.

[0005] The objective of this application is achieved through the following technical solution:

[0006] In a first aspect, this application provides a black-start control method applied to at least one of multiple energy storage converters connected in parallel in an energy storage system. The method includes: upon receiving a black-start control command, determining the output frequency of the active power loop in the energy storage system based on a target frequency and a frequency droop control term; and determining the output voltage of the reactive power loop in the energy storage system based on a target voltage, a voltage droop control term, and a voltage compensation term; wherein the voltage compensation term is determined based on the transmission impedance of the energy storage converter to which the black-start control method is applied; and determining an output voltage reference value for achieving black-start of the energy storage converter based on the output frequency of the active power loop and the output voltage of the reactive power loop in the energy storage system, so as to control the output power of the energy storage converter.

[0007] In some embodiments, determining the output frequency of the active power loop based on the target frequency and a frequency droop control term includes: determining the output frequency of the active power loop based on the target frequency, the frequency droop control term, and a frequency adjustment deviation term; wherein the frequency adjustment deviation term is used to indicate the deviation between the actual output frequency of the active power loop and the average value of the actual output frequencies of each active power loop; and / or, determining the output voltage of the reactive power loop based on the target voltage, a voltage droop control term, and a voltage compensation term includes: determining the output voltage of the reactive power loop based on the target voltage, a voltage droop control term, a voltage adjustment deviation term, and a voltage compensation term; wherein the voltage adjustment deviation term is used to indicate the deviation between the actual output voltage of the reactive power loop and the average value of the actual output voltages of each reactive power loop.

[0008] In some embodiments, the target frequency is determined based on the average value of the actual output frequencies of the parallel energy storage converter, and / or the target voltage is determined based on the average value of the actual output voltages of the parallel energy storage converter.

[0009] In some embodiments, at least two of the plurality of energy storage converters satisfy the following conditions: the absolute value of the difference between the product of reactive power and transmission reactance of the two energy storage converters is less than a preset value, wherein the transmission reactance includes virtual reactance and line reactance; the absolute value of the difference between the product of active power and transmission resistance of the two energy storage converters is less than a preset value, wherein the transmission resistance includes virtual resistance and line resistance; and the absolute value of the difference between the ratio of reactive power-voltage droop coefficient to transmission reactance of the two energy storage converters is less than a preset value.

[0010] In some embodiments, the voltage compensation term is determined based on the active power, line resistance, reactive power, line reactance, and output voltage of the energy storage converter.

[0011] In some embodiments, the frequency droop control term is determined based on the active power-frequency droop coefficient and the active power adjustment amount, the active power adjustment amount being used to indicate the difference between the actual active power and the target active power, and / or, the voltage droop control term is determined based on the reactive power-voltage droop coefficient and the reactive power adjustment amount, the reactive power adjustment amount being used to indicate the difference between the actual reactive power and the target reactive power.

[0012] In some embodiments, determining the output voltage reference value for achieving black start of the energy storage converter based on the output frequency of the active power loop and the output voltage of the reactive power loop includes: determining a target voltage reference value for achieving black start of the energy storage converter based on the output frequency of the active power loop and the output voltage of the reactive power loop; and calculating the output voltage reference value for achieving black start of the energy storage converter based on the target voltage reference value for achieving black start, the output current of the energy storage converter, and the virtual impedance.

[0013] Secondly, this application provides a control module for executing any of the above methods.

[0014] Thirdly, this application provides an energy storage converter, which includes any of the control modules mentioned above.

[0015] Fourthly, this application provides an energy storage converter for performing any of the above methods.

[0016] Fifthly, this application provides an energy storage system, which includes multiple energy storage converters connected in parallel, and at least one energy storage converter includes any of the control modules mentioned above.

[0017] Sixthly, this application provides a black-start control method applied to a controller in an energy storage system. The energy storage system includes the controller and multiple energy storage converters connected in parallel. The method includes: sending black-start control commands to a target number of energy storage converters so that the energy storage converters execute any of the above methods to achieve black-start control of the energy storage converters; and determining that the energy storage system has successfully started when the target number of energy storage converters have successfully started.

[0018] In some embodiments, the process of determining the target quantity includes: determining the target quantity using the maximum power required for the black start process, the multiplier, and the individual power of the energy storage converter; wherein the maximum power is calculated based on the maximum superimposed power of the lines, transformers, and loads of the energy storage system during the black start process.

[0019] In some embodiments, for each energy storage converter, the process of determining whether the black start of the energy storage converter is successful includes: upon receiving a successful power-on signal returned by the target number of energy storage converters, sending an establishment voltage command carrying a first preset voltage rise gradient to the energy storage converter, so that the energy storage converter determines the target voltage according to the first preset voltage rise gradient; upon receiving a startup completion signal uploaded by the energy storage converter, determining that the black start of the energy storage converter is successful; the startup completion signal is generated after the energy storage converter raises its own output voltage to the target voltage threshold.

[0020] In a seventh aspect, this application provides a controller for performing any of the methods described above.

[0021] Eighthly, this application provides a chip for performing any of the above methods.

[0022] Ninthly, this application provides a computer-readable storage medium storing a computer program, which is executed by a processor using any of the methods described above.

[0023] In a tenth aspect, this application provides a computer program product comprising a computer program, wherein the computer program is executed by a processor using any of the methods described above.

[0024] This application provides a black-start control method, an energy storage converter, an energy storage system, and related devices. The black-start control method is applied to at least one of multiple energy storage converters connected in parallel in an energy storage system. The method includes: upon receiving a black-start control command, determining the output frequency of the active power loop in the energy storage system based on a target frequency and a frequency droop control term; and determining the output voltage of the reactive power loop in the energy storage system based on a target voltage, a voltage droop control term, and a voltage compensation term; and determining a reference value for the output voltage used to achieve black-start of the energy storage converter based on the output frequency of the active power loop and the output voltage of the reactive power loop in the energy storage system, thereby controlling the output power of the energy storage converter. This application introduces a voltage compensation term to improve the consistency of the transmission impedance among multiple energy storage converters, making the transmission impedance of multiple energy storage converters as constant and equal as possible, thereby controlling the output voltage synchronization of the parallel energy storage converters and reducing the system circulating current between the energy storage converters. Therefore, this application can improve the consistency and simultaneity of multi-machine control, enabling successful black-start of a multi-machine parallel energy storage system. Attached Figure Description

[0025] This application will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] Figure 1 is a schematic diagram of the black start control process of an energy storage converter provided in an embodiment of this application.

[0027] Figure 2 is a flowchart illustrating a black start control method provided in an embodiment of this application.

[0028] Figure 3 is a schematic flowchart of a voltage and current dual closed-loop control provided in an embodiment of this application.

[0029] Figure 4a is a schematic diagram of the transmission impedance of a first energy storage converter provided in this application.

[0030] Figure 4b is a schematic diagram of the transmission impedance of a second energy storage converter provided in this application.

[0031] Figure 5 is a schematic diagram of the black start control process of another energy storage converter provided in the embodiment of this application (including frequency regulation deviation and voltage regulation deviation).

[0032] Figure 6 is a schematic diagram of the black start control process of another energy storage converter provided in the embodiments of this application (including frequency regulation deviation, voltage regulation deviation and virtual impedance).

[0033] Figure 7 is a schematic diagram of the circuit structure of a two-machine parallel system provided in an embodiment of this application.

[0034] Figure 8 is a structural block diagram of a computer device provided in an embodiment of this application. Detailed Implementation

[0035] The technical solutions in the embodiments of this application 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 application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] In the description of the embodiments of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0037] Energy storage systems, characterized by rapid response and hourly output, meet the black-start requirements of systems disconnected from the main grid after a fault. Among these, VSG technology, due to its controlled voltage source characteristics, has become an important means to improve the stable operation of grid-connected and off-grid systems in weak grid environments. Large-capacity energy storage systems are generally composed of multiple energy storage units connected in parallel. During black-start off-grid operation, the energy storage converters in the energy storage units are usually connected in parallel using voltage source modes such as droop and VSG. However, parallel operation is prone to a series of problems such as oscillation, circulating current, and uneven power distribution. Black-starting multiple energy storage converters in parallel places high demands on the consistency and simultaneity of multi-machine control, which is also the key to the success of black-starting.

[0038] Factors such as reference voltage, sampling error, main circuit parameters, dead time, transmission impedance, and control delay can cause circulating current in the system. This circulating current leads to discrepancies in the output voltage reference value of the energy storage converter, and it increases with the deviation of the reference value. Circulating current prevents the system from accurately distributing reactive power, and in severe cases, excessive circulating current can damage the energy storage converter. From the above analysis of the system circulating current characteristics, it is clear that the output voltage of parallel energy storage converters should be synchronized as much as possible, and the transmission impedance of multiple energy storage converters should be kept as constant and equal as possible. Inductive impedance of the system transmission impedance should be increased to reduce the circulating current. While the virtual impedance of the energy storage converter can improve power distribution and reduce circulating current, it increases the system transmission impedance, leading to increased voltage drop across the energy storage converter and decreased power quality at the point of common coupling.

[0039] Referring to Figures 1 and 2, Figure 1 is a schematic diagram of the black-start control process of an energy storage converter according to an embodiment of this application, and Figure 2 is a flowchart of a black-start control method according to an embodiment of this application. In Figure 1, I oi U is the actual output current of the energy storage converter. oi This represents the actual output voltage of the energy storage converter (e.g., the RMS value of the line voltage). i This represents the actual active power of the energy storage converter. For the target active power of the energy storage converter, ΔP i m is the active power regulation of the energy storage converter. i f is the active-frequency droop factor of the energy storage converter. set f is the target frequency of the output voltage of the energy storage converter. i δ is the frequency of the output voltage of the energy storage converter (i.e., the output frequency of the active power loop), s is the Laplace factor, and δ i Q represents the output phase angle of the active power loop in the energy storage system. i This represents the actual reactive power of the energy storage converter. ΔQ is the target reactive power of the energy storage converter. i n represents the reactive power regulation of the energy storage converter. i E is the reactive power-voltage droop factor of the energy storage converter. * For the target voltage (e.g., peak phase voltage) of the energy storage converter, ΔU ci For the voltage compensation term of the energy storage converter, U i This is the output voltage of the reactive power loop in the energy storage system.

[0040] In order to improve the relevant technology, this application provides a black start control method, which is applied to at least one of multiple energy storage converters connected in parallel in an energy storage system. The method includes steps S101 to S102.

[0041] Step S101: Upon receiving a black-start control command, determine the output frequency of the active power loop based on the target frequency and the frequency droop control term; and determine the output voltage of the reactive power loop based on the target voltage, the voltage droop control term, and the voltage compensation term. The voltage compensation term is determined based on the transmission impedance of the energy storage converter used in the black-start control method.

[0042] Step S102: Based on the output frequency of the active power loop and the output voltage of the reactive power loop, determine the output voltage reference value for achieving black start of the energy storage converter, so as to control the output power of the energy storage converter.

[0043] In some embodiments, the control method described above can be executed on a control module. This control module can be integrated into the energy storage converter or installed separately.

[0044] The above embodiments target frequency f set It is not limited to this, and can be selected or set according to the needs of the actual application. In some embodiments, the target frequency f set 50Hz can be used.

[0045] The above embodiments address the target voltage E. * Without limitation, it can be selected or set according to the needs of the actual application. In some embodiments, the target voltage E * The peak value of the phase voltage can be used.

[0046] The above embodiments target active power and / or target reactive power There are no restrictions; for example, the selection or setting can be based on the needs of the actual application.

[0047] As an example, the output frequency f of the active power loop in the above embodiment can be...i and the output voltage U of the reactive power loop i This is expressed as formula (1).

[0048] in,

[0049] The above embodiments improve the droop control process to address the problem of uneven reactive power distribution caused by inconsistent transmission impedance. Specifically, in the droop control process, an additional voltage compensation term is introduced for the voltage control section. This term compensates for the additional voltage drop generated by the power line impedance, improving the rational distribution of reactive load among the energy storage converters, reducing circulating current among multiple parallel energy storage converters, and thus resolving the contradiction between the power sharing accuracy and output voltage drop of each energy storage converter during the droop control process. Therefore, the voltage compensation term improves the consistency and simultaneity of multi-machine control, ensuring successful black start of the multi-machine parallel energy storage system.

[0050] To ensure that the voltage remains within the required range (e.g., between 97% and 105% of the rated voltage), the above embodiments incorporate a voltage compensation term to compensate for the additional voltage drop across the line impedance, thereby improving the rational distribution of reactive power and reducing system circulating current. In some embodiments, the voltage compensation term can be determined based on active power, line resistance, reactive power, line reactance, and output voltage.

[0051] For example, the voltage compensation term ΔU ci It can be calculated using formula (2).

[0052] Among them, R ci X is the line resistance. ci For line reactance. As an example, in the case of an energy storage converter connected to a filter unit, U oi It can be the filtered output voltage.

[0053] In the above embodiments, the voltage compensation term is determined based on active power, line resistance, reactive power, line reactance, and output voltage. This ensures that the calculation of the voltage compensation term takes into account the differences in line impedance between each energy storage converter, enabling targeted compensation and achieving consistent control of the transmission impedance of each energy storage converter. This compensation precisely corresponds to the corresponding energy storage converter and is applicable to the voltage compensation term calculation of each energy storage converter. It is accurate and efficient, consumes few computational resources, has a fast response speed, and can reduce the risk of failure during black start.

[0054] Referring to Figure 3, Figure 3 is a schematic flowchart of a voltage and current dual closed-loop control provided in an embodiment of this application.

[0055] The following example illustrates the process of implementing black-start control of the energy storage converter using the aforementioned output voltage reference value. As an example, as shown in Figure 3, the output voltage reference value u used to achieve black-start control of the energy storage converter is first... refi Input the outer voltage loop to obtain the current reference value i output by the outer voltage loop. refi Secondly, the current reference value i output from the outer voltage loop is... refi Input the inner current loop to obtain the voltage reference value e output by the inner current loop. refi Then, the voltage reference value e output by the inner current loop is... refi Input the DC-side voltage modulation loop of the energy storage converter to obtain the voltage reference value output by the DC-side voltage modulation loop of the energy storage converter. Next, the voltage reference value output by the DC-side voltage modulation loop of the energy storage converter can be used. A control signal is generated, which in turn controls the output power of the energy storage converter. This control signal can be, for example, a PWM (Pulse Width Modulation) control signal.

[0056] In the initial stage of black start described above, the energy storage system operates off-grid, and the energy storage converter regulates active and reactive power according to the droop factor. During this stage, it is necessary to maintain the output voltage and frequency of the energy storage converter within a certain range. During grid-connected operation, the droop control process of the energy storage system outputs constant active and reactive power by adjusting the voltage frequency and voltage amplitude. The use of droop control throughout the entire black start process reduces the switching between V / f control and P / Q control during black start, simplifies the control system, and improves reliability.

[0057] Excessive differences in transmission impedance among the energy storage converters can lead to circulating current in the system. To reduce the differences in transmission impedance among the energy storage converters, in some embodiments, at least two energy storage converters can satisfy the following conditions: In one of the two energy storage converters, the product of reactive power and transmission reactance of one energy storage converter matches the product of reactive power and transmission reactance of the other energy storage converter, where the transmission reactance includes virtual reactance and line reactance; in another of the two energy storage converters, the product of active power and transmission resistance of one energy storage converter matches the product of active power and transmission resistance of the other energy storage converter, where the transmission resistance includes virtual resistance and line resistance; and in yet another of the two energy storage converters, the ratio of reactive power-voltage droop factor to transmission reactance of one energy storage converter matches the ratio of reactive power-voltage droop factor to transmission reactance of the other energy storage converter.

[0058] In the above embodiments, matching object A and object B means, for example, that the absolute value of the difference between object A and object B is less than a preset value, or that the ratio of the absolute value of the difference between object A and object B to the ratio of object B is less than a preset ratio. The preset value or preset ratio can be selected or set according to the needs of actual applications, and the above embodiments do not limit this. As an example, object A is the product of the reactive power and transmission reactance of the first energy storage converter, and object B is the product of the reactive power and transmission reactance of the second energy storage converter. As another example, object A is the product of the active power and transmission resistance of the first energy storage converter, and object B is the product of the active power and transmission resistance of the second energy storage converter. As yet another example, object A is the ratio of the reactive power-voltage droop coefficient to the transmission reactance of the first energy storage converter, and object B is the ratio of the reactive power-voltage droop coefficient to the transmission reactance of the second energy storage converter.

[0059] Referring to Figures 4a and 4b, Figure 4a is a schematic diagram of the transmission impedance of a first energy storage converter provided in this application, and Figure 4b is a schematic diagram of the transmission impedance of a second energy storage converter provided in this application.

[0060] To improve the flexibility of droop control and reduce system circulating current, the above embodiments limit the transmission impedance of each energy storage converter to meet the matching conditions of formulas (3) and (4). At this time, the output voltage reference value can be regarded as the same value, and the reactive load can be reasonably shared according to the reactive power and the set reactive-voltage droop coefficient. As an example, when connecting the line reactance of each energy storage converter, the reactive-voltage droop coefficient ratio can be set according to the rated capacity of each energy storage converter, and the line reactance can be compensated by virtual reactance, thereby realizing the proportional sharing of reactive load.

[0061] Wherein, subscripts 1 and 2 represent the serial numbers of the energy storage converters. Q1 represents the actual reactive power of the first energy storage converter, Q2 represents the actual reactive power of the second energy storage converter, and X... v1 X is the virtual reactance of the first energy storage converter. c1 X is the line reactance of the first energy storage converter. v2 X is the virtual reactance of the second energy storage converter. c2 P1 is the line reactance of the second energy storage converter. P2 is the actual active power of the first energy storage converter, and R is the actual active power of the second energy storage converter. v1 R is the virtual resistance of the first energy storage converter. c1 R is the line resistance of the first energy storage converter. v2 R is the virtual resistance of the second energy storage converter. c2n1 is the line resistance of the second energy storage converter. n2 is the reactive power-voltage droop coefficient of the first energy storage converter and n2 is the reactive power-voltage droop coefficient of the second energy storage converter.

[0062] During normal operation, the phase angle difference δ in the output voltage reference phasor of the energy storage converter is very small, and there is an integral element in the active droop control structure. Therefore, the active component of the system circulating current is low, and the circulating current in the parallel energy storage converter system mainly has reactive characteristics. The reactive component corresponds to the transmission reactance. Therefore, the consistency control of the transmission reactance in the transmission impedance can be prioritized, that is, formulas (3) and (4) can be used to ensure the consistency control of the transmission reactance of each energy storage converter. As an example, each energy storage converter can meet the following conditions: That is, the reactive power-voltage droop coefficient of each energy storage converter is output inversely proportional to the actual reactive power of the energy storage converter.

[0063] In some embodiments, the frequency droop control term can be determined based on the active power-frequency droop coefficient and the active power adjustment amount, wherein the active power adjustment amount is used to indicate the difference between the actual active power and the target active power. In some embodiments, the voltage droop control term can be determined based on the reactive power-voltage droop coefficient and the reactive power adjustment amount, wherein the reactive power adjustment amount is used to indicate the difference between the actual reactive power and the target reactive power.

[0064] To obtain the expressions for the frequency droop control term and the voltage droop control term, the frequency droop control term and the voltage droop control term can be defined according to the droop control equation. As an example, the frequency droop control term can be expressed as -m i ·ΔP i The voltage droop control term can be expressed as -n i ·ΔQ i Therefore, the calculation of the frequency droop control term takes into account the active power-frequency droop coefficient and the active power adjustment, with the active power adjustment determined based on the difference between the actual active power and the target active power, thus achieving accurate calculation of the frequency droop control term for each energy storage converter. Similarly, the calculation of the voltage droop control term takes into account the reactive power-voltage droop coefficient and the reactive power adjustment, with the reactive power adjustment determined based on the difference between the actual reactive power and the target reactive power, thus achieving accurate calculation of the voltage droop control term for each energy storage converter.

[0065] Referring to Figure 5, Figure 5 is a schematic diagram of the black-start control process of another energy storage converter provided in an embodiment of this application (including frequency regulation deviation and voltage regulation deviation). In Figure 5, f iLet f be the actual output frequency of the energy storage converter, and Δf be the average actual output frequency of each energy storage converter. i This is the frequency regulation deviation term; PI stands for Proportional-Integral (PI) controller. This is an addition operation. The average value of the actual output voltage of each energy storage converter, ΔU oi This is the voltage regulation deviation term.

[0066] In relevant droop control methods, the droop coefficients m and n are constants, and the active-frequency droop characteristic and reactive-voltage droop characteristic are linear with fixed slopes. This results in low flexibility in droop control, leading to poor consistency and simultaneity in the control of multiple energy storage converters, making it difficult to reduce system circulating current. When the system circulating current is large, it is difficult to accurately allocate reactive power, and it may even damage related hardware. In some embodiments, determining the output frequency of the active power loop based on the target frequency and the frequency droop control term may include: determining the output frequency of the active power loop based on the target frequency, the frequency droop control term, and the frequency adjustment deviation term; wherein the frequency adjustment deviation term indicates the deviation between the actual output frequency of the active power loop and the average value of the actual output frequencies of all active power loops. In some embodiments, determining the output voltage of the reactive power loop based on the target voltage, voltage droop control term, and voltage compensation term may include: determining the output voltage of the reactive power loop based on the target voltage, voltage droop control term, voltage regulation deviation term, and voltage compensation term; wherein the voltage regulation deviation term is used to indicate the deviation between the actual output voltage of the reactive power loop and the average value of the actual output voltages of each reactive power loop.

[0067] In the above embodiments, a frequency regulation deviation term is introduced in the process of determining the output frequency, and a voltage regulation deviation term is introduced in the process of determining the output voltage. Furthermore, the above method can be applied to at least one of multiple energy storage converters, thereby achieving masterless consistency control of the output voltage reference value. Since there is no master-slave distinction among the various energy storage converters, this can be seen as combining a masterless consistency control method with droop control equations to reduce transient fluctuations in transmission line frequency and voltage during the black-start power restoration phase.

[0068] For example, to minimize the output voltage amplitude deviation of each energy storage converter, the above embodiment introduces feedback control of the output voltage amplitude in the reactive power control loop, which enhances the ability of the energy storage converter's output voltage to track changes in the reference signal value. As an example, by adding a PI regulator to the amplitude feedback control, the output voltage U of the reactive power loop... i It can be expressed as formula (5.1).

[0069] In other words, the output voltage U of the reactive power loop i Based on the target voltage E T Voltage droop control item Voltage regulation deviation term ΔU oi and voltage compensation term ΔU ci This is determined to achieve masterless consistency control of the output voltage of the reactive power control loop.

[0070] Accordingly, to minimize the output frequency deviation of each energy storage converter, the above embodiment introduces output frequency feedback control into the active power control loop, which enhances the ability of the energy storage converter's output frequency to track changes in the reference signal value. As an example, by adding a PI regulator to the frequency feedback control, the output frequency f of the active power loop... i This can be expressed as formula (5.2).

[0071] In other words, the output frequency f of the active power loop i Based on the target frequency f set Frequency droop control item and frequency adjustment deviation term Δf i This is determined to achieve masterless consistency control of the output frequency of the active power control loop.

[0072] In some embodiments, the frequency regulation deviation term may include a frequency regulation proportional term and a frequency regulation integral term. In some embodiments, the voltage regulation deviation term may include a voltage regulation proportional term and a voltage regulation integral term. Besides using a PI controller, other types of controllers such as PID controllers may also be used, and the above embodiments are not limited to this.

[0073] For example, suppose an energy storage system (e.g., a wind-solar-storage microgrid system) restores power, the transmission lines are fully charged, and multiple micro-sources (e.g., various power sources included in a wind-solar-storage microgrid system) and loads operate in parallel. Now, it is necessary to expand the black-start power restoration area. Unlike related motors, energy storage converters lack inertial links, often experiencing transient frequency and voltage fluctuations during active and reactive power regulation. This adversely affects the stability of the entire system and can lead to black-start failure in severe cases. To increase the robustness of the energy storage droop control process during the black-start power restoration phase, nonlinear compensation methods can be used to compensate for active-frequency and reactive-voltage droop control.

[0074] Specifically, in order to reduce the deviation between the corresponding output frequency and output voltage of each energy storage controller, a frequency regulation deviation term Δf can be introduced. i and voltage regulation deviation term ΔU oi Adjust the deviation term Δf according to the frequency. i and voltage regulation deviation term ΔU oi The frequency and voltage are adjusted in a timely manner, as shown in formula (6).

[0075] Where, k pf k pU These are the proportional coefficients in the PI control corresponding to the frequency and voltage deviations, respectively; k if k iU These are the integral coefficients in the PI regulation corresponding to the frequency and voltage deviations, respectively. Therefore, by introducing the average value of the actual output frequency of the active power loop of each energy storage converter... To achieve consistent output frequency control of the active power loop of the energy storage converter. Similarly, this is achieved by introducing the average value of the actual output voltage of the reactive power loop of each energy storage converter. This achieves consistent control of the output voltage of the reactive power loop in the energy storage converter. Furthermore, this consistent control process for output frequency and output voltage does not require the setting of a master and slave unit, thus enabling masterless consistent control.

[0076] Substituting formula (6) obtained from the masterless consistency control into formulas (5.1) and (5.2) can reduce the transient fluctuations in transmission line frequency and voltage during the black-start power restoration phase. In the above embodiment, the frequency adjustment deviation term Δf is used. i and voltage regulation deviation term ΔU oi By correcting frequency and voltage deviations and feeding the deviation values ​​back to the droop control system, the frequency and amplitude control of the output voltage of each energy storage converter can be made more precise.

[0077] Referring to Figure 6, Figure 6 is a schematic diagram of the black-start control process of another energy storage converter provided in an embodiment of this application (including frequency regulation deviation term, voltage regulation deviation term, and virtual impedance). In Figure 6, Z vi The virtual impedance of the energy storage converter. u is the target voltage reference value. refi This is the reference value for the output voltage.

[0078] In some embodiments, determining the output voltage reference value for achieving black start of the energy storage converter based on the output frequency of the active power loop and the output voltage of the reactive power loop may include: determining a target voltage reference value for achieving black start of the energy storage converter based on the output frequency of the active power loop and the output voltage of the reactive power loop; and calculating the output voltage reference value for achieving black start of the energy storage converter based on the target voltage reference value for achieving black start, the output current of the energy storage converter, and the virtual impedance.

[0079] As shown in Figure 6, based on the output frequency f of the active power loop i and the output voltage U of the reactive power loop i Determine the target voltage reference value for the energy storage converter. Based on the target voltage reference value of the energy storage converter Output current I oi and virtual impedance Z vi The output voltage reference value u of the energy storage converter is calculated. refi As an example,

[0080] The above embodiments propose a strategy for reactive power droop factor matching control when multiple energy storage converters are connected in parallel. By selecting an appropriate virtual impedance, it is beneficial to improve the power distribution effect and reduce the system circulating current. The average value of the actual output frequency of each energy storage converter is used. Average value of actual output voltage The frequency and voltage regulation deviations for each energy storage converter are calculated. The differences between the actual output frequency and voltage of each energy storage converter and their corresponding average values ​​are considered when determining the output voltage reference value. Therefore, the reactive load among the energy storage converters can be reasonably allocated. As an example, the average value of the actual output frequency of each energy storage converter... Average value of actual output voltage The central controller can interact with each energy storage converter and perform real-time calculations. The central controller is the upper-level control device that interacts with each energy storage converter. In addition, the above embodiments incorporate a voltage compensation term to compensate for the additional voltage drop generated by the power line impedance, improving the rational distribution of reactive loads and reducing system circulating current. Furthermore, the above embodiments combine a masterless consistency control method with droop control equations, which can reduce the frequency and voltage transient fluctuations of the transmission line during the black-start power restoration phase. Therefore, by introducing voltage compensation terms, frequency regulation deviation terms, voltage regulation deviation terms, and virtual impedance, masterless consistency and simultaneity of multi-machine control are achieved, ensuring successful black-start of the multi-machine parallel energy storage system.

[0081] This application also provides a control module for executing the methods mentioned in any of the above embodiments.

[0082] This application also provides an energy storage converter, which includes the control module described above.

[0083] This application embodiment also provides an energy storage system, which includes multiple energy storage converters connected in parallel, and at least one energy storage converter includes the above-mentioned control module.

[0084] This application also provides a black-start control method applied to a controller in an energy storage system. The energy storage system includes the controller and multiple energy storage converters connected in parallel. The method includes: sending black-start control commands to a target number of energy storage converters so that the energy storage converters execute any of the above methods to achieve black-start control of the energy storage converters; and determining that the energy storage system has successfully started when the target number of energy storage converters have successfully started.

[0085] The above embodiments do not limit the target quantity, which can be, for example, 2, 3, 4, etc.

[0086] In some embodiments, the process of determining the target quantity may include: determining the target quantity using the maximum power required for the black start process, the multiplier factor, and the individual power of the energy storage converter; wherein, the maximum power is calculated based on the maximum superimposed power of the lines, transformers, and loads (i.e., the sum of the electrical load power of all electrical equipment in the system) of the energy storage system during the black start process. The multiplier factor refers to a coefficient that can be multiplied by the required maximum power considering redundancy design, for example, 1.1. Individual power refers to the power of a single energy storage converter. Transformers in the black start process refer to transformers involved in the black start path, such as step-up transformers connected to the energy storage converters, transformers passing through substations in the lines, and step-down transformers connected to the loads.

[0087] In the above embodiments, the actual number of parallel energy storage converters participating in black start can be determined by the maximum power required during black start, the multiplier factor, and the individual power of the energy storage converter. For example, the required maximum power can be calculated based on the black start process defined by the EMS (Energy Management System) in the upper-level central controller. For instance, it can be the maximum superimposed power of the lines, transformers, and loads at a given time point during the entire black start process. As an example, the expression for the maximum superimposed power can include line calculation terms, transformer calculation terms, and load calculation terms. When the load includes impulsive loads, a starting inrush current factor can be set for the load calculation term. Furthermore, during the calculation of the transformer calculation term, the requirement for the short-time reactive voltage withstand capability of the energy storage converter due to the inrush current during transformer magnetization can be considered. After calculating the required maximum power, the maximum power can be multiplied by the multiplier factor K. s This is then divided by the power of a single energy storage converter, and rounded to the nearest integer to obtain the actual number of parallel energy storage converters required for black start, i.e., the target number. Here, "load" refers to the load carried by the system during normal operation, such as the electrical equipment used in manufacturing, hydrogen production, and seawater desalination processes.

[0088] In some embodiments, for each energy storage converter, the process of determining whether the black start of the energy storage converter is successful may include: upon receiving a successful power-on signal returned by the target number of energy storage converters, sending an establishment voltage command carrying a first preset voltage rise gradient to the energy storage converter, so that the energy storage converter determines the target voltage according to the first preset voltage rise gradient; upon receiving a startup completion signal uploaded by the energy storage converter, determining that the black start of the energy storage converter is successful; the startup completion signal is generated after the energy storage converter raises its own output voltage to the target voltage threshold.

[0089] For example, in a specific application scenario, assume the energy storage system includes a controller and multiple energy storage converters, with a target number of two. The controller sends a black-start control command to two energy storage converters. Upon receiving the black-start control command, each energy storage converter performs a power-on start-up and connects the two converters in parallel, returning a power-on success signal to the controller. Upon receiving the power-on success signals from the two energy storage converters, the controller sends a voltage establishment command carrying a first preset voltage rise gradient to the two converters. Upon receiving the voltage establishment command carrying the first preset voltage rise gradient, each energy storage converter increases its output voltage (e.g., the output voltage of the AC port) to a first voltage threshold according to the first preset voltage rise gradient. When each energy storage converter detects that its output voltage (e.g., the output voltage of the AC port) has reached the first voltage threshold, it performs droop-parallel networking. After being connected in a droop-parallel network, each energy storage converter increases its output voltage (e.g., the output voltage of the AC port) to a target voltage threshold (e.g., the second voltage threshold) according to a first preset voltage rise gradient or a second preset voltage rise gradient. When each energy storage converter detects that its output voltage (e.g., the output voltage of the AC port) has reached the target voltage threshold, it uploads a start-up completion signal to the controller. Upon receiving the start-up completion signal uploaded by the energy storage converter, the controller determines that the energy storage converter has successfully started. If both energy storage converters have successfully started, the energy storage system is considered to have successfully started.

[0090] As can be seen from the above, during the process of the energy storage converter receiving the voltage establishment command and increasing its output voltage to the first voltage threshold, the target voltage of the reactive power loop can be determined according to the first preset voltage rise gradient. During the process of the energy storage converter in parallel grid connection increasing its output voltage to the target voltage threshold, the target voltage of the reactive power loop can be determined according to either the first preset voltage rise gradient or a second preset voltage rise gradient; the above embodiments do not limit this. The second preset voltage rise gradient can be different from the first preset voltage rise gradient.

[0091] Referring to Figure 7, which is a schematic diagram of the circuit structure of a two-machine parallel system provided in an embodiment of this application, the two-machine parallel system in Figure 7 can be regarded as an example of two parallel energy storage converters participating in black start. In Figure 7, AC stands for Alternating Current, and RLC stands for Relay Logic Circuit.

[0092] In a specific application scenario, assume the energy storage system includes a controller (e.g., an RLC controller) and multiple energy storage converters connected in parallel, which can be controlled by VSG, for example. The energy storage system may also include switches corresponding to each energy storage converter, such as switches S1 and S2. The voltage output by the controller can be, for example, P+jQ.

[0093] The following example illustrates the black start control process of this energy storage system.

[0094] First, the controller can close the corresponding switches of the two energy storage converters, namely switch S1 and switch S2.

[0095] Secondly, each energy storage converter can convert the target active power and target reactive power Set to 0.

[0096] Next, each energy storage converter can output phase angle δ i The default value is set to 0, which sets the target initial value of the voltage ramp function (i.e., the initial value of the output voltage) to 0. Within a time period T1, the output voltage is raised to the rated voltage (as an example of a first voltage threshold) according to the voltage ramp function. The first set slope of the voltage ramp function can be determined based on a first preset voltage rise gradient. For example, T1 is 1 second, and the energy storage converter can automatically boost the voltage at a rate of 100% / s. The rated voltage can be selected or set according to the needs of the actual application. Multiple energy storage converters can be started simultaneously, meaning that the phase angle and initial voltage value of multiple energy storage converters can be initialized simultaneously.

[0097] Next, each energy storage converter, along with its transformer and lines, undergoes no-load charging. Within a time period T2, the voltage is controlled to rise according to a second preset slope, increasing its output voltage to a second voltage threshold. The second preset slope can be determined based on a first preset voltage rise gradient, or vice versa. For example, T2 might be 1 second, and the energy storage converter could automatically boost its voltage at a rate of 100% / s. No-load charging, for example, refers to the energy storage converter only carrying some auxiliary loads.

[0098] Subsequently, each energy storage converter gradually restores the energy storage system according to the source-load balance principle (e.g., gradually activating new energy power generation and loads) to minimize the impact of load grid connection on system voltage and frequency. Here, "load grid connection" refers to the loads within the system, such as auxiliary equipment, lighting equipment, heating equipment, motors, water pumps, and other electrical equipment.

[0099] When an energy storage system serves as the main power source for black start in a regional power grid, parallel energy storage converters are often required to provide the power needed for black start in the area. This places high demands on the simultaneity and consistency of the outputs of each energy storage converter in the system. The above-described embodiment can improve the simultaneity and consistency of the outputs of each energy storage converter, reduce circulating currents in the system, and lower the risk of damage to hardware devices in the system.

[0100] This application also provides a controller for executing any of the above-described black-start control methods for controllers applied in energy storage systems.

[0101] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements any of the above methods.

[0102] This application also provides a computer program product, which includes a computer program that, when executed by a processor, implements any of the methods described above.

[0103] The computer program product may be in the form of a portable compact disc read-only memory (CD-ROM) and include program code, and may run on a terminal device, such as a personal computer. However, the computer program product of this application is not limited thereto, and the computer program product may be in any combination of one or more computer-readable media.

[0104] This application also provides a chip for performing any of the above methods.

[0105] Referring to Figure 8, Figure 8 is a structural block diagram of a computer device 100 provided in an embodiment of this application.

[0106] This application embodiment also provides a computer device 100, which includes a memory 110 and a processor 120. The memory 110 stores a computer program, and the processor 120 executes the computer program to implement any of the above methods.

[0107] The embodiments of this application do not limit the computer device 100, which may be, for example, a local computer device, a cloud computer device, a distributed computer device, etc.

[0108] The computer device 100 may include a memory 110, a processor 120, and a communication interface 130. The memory 110, the processor 120, and the communication interface 130 are connected through internal connection paths.

[0109] The memory 110 is used to store computer programs, which in some implementations may include code for implementing the methods of the embodiments of this application.

[0110] The processor 120 executes the computer program stored in the memory 110 to control the communication interface 130 to receive input data and information, and output operation results and other data. In some implementations, when the solutions of the embodiments of this application are implemented by software or firmware, the computer program used to implement the solutions of the embodiments of this application can be stored in the processor 120 and executed by the processor 120.

[0111] The memory 110 may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory may be random access memory (RAM). It should be noted that the memory 110 described herein is intended to include, but is not limited to, any memory of these and other suitable types. As an example, the memory 110 includes random access memory (RAM), cache memory, and read-only memory (ROM). The memory 110 stores a computer program that can be executed by processor 120, causing processor 120 to implement the steps of any of the methods described above.

[0112] The processor 120 can be a central processing unit (CPU), or it can 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. The general-purpose processor can be a microprocessor, or the processor 120 can be any conventional processor.

[0113] In implementation, each step of the above method can be completed by the integrated logic circuitry of the hardware in the processor 120 or by instructions in software form. The method disclosed in the embodiments of this application can be directly implemented by the hardware processor, or by a combination of hardware and software modules in the processor 120. The software modules can be located in mature storage media in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in the memory 110, and the processor 120 reads the information in the memory 110 and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are not provided here.

[0114] In some implementations, the computer device 100 may include software modules in addition to the hardware units described above. These software modules may include, for example, an operating system, a basic input / output system (BIOS), or application software.

[0115] The operating system manages the hardware and / or software resources of computer device 100 and is the kernel and foundation of computer device 100. The operating system handles basic tasks such as managing and configuring memory, determining the priority of system resource allocation and demand, controlling input and output devices, operating the network, and managing the file system. To facilitate user operation, most operating systems provide a user interface for interaction with the system.

[0116] The BIOS is used to perform hardware initialization during the power-on boot phase and to provide runtime services for the operating system and applications. In some implementations, the BIOS can also monitor and display processor temperature and execute temperature protection strategies.

[0117] Application software, also known as an application program, can be understood as software written for a specific user application purpose, and is one of the main categories of computer software. For example, application software can be a program used to achieve purposes such as power control and temperature management.

[0118] It is understood that the specific examples in this application are only intended to help those skilled in the art better understand the implementation of this application, and are not intended to limit the scope of protection of this application.

[0119] It is understood that in the various embodiments of this application, the sequence number of each process 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 this application.

[0120] It is understood that the various implementation methods described in this application can be implemented individually or in combination, and this application does not limit them.

[0121] Unless otherwise stated, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items. The singular forms "a," "the," and "the" as used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0122] 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.

[0123] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the embodiments described above can be referred to the corresponding processes in other embodiments, and will not be repeated here.

[0124] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units 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 mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0125] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the technical solution in this application, depending on actual needs.

[0126] In addition, the functional units in the various embodiments of this application 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.

[0127] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, essentially, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0128] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A black-start control method, characterized in that, The method, applied to at least one of multiple energy storage converters connected in parallel in an energy storage system, includes: Upon receiving a black-start control command, the output frequency of the active power loop in the energy storage system is determined based on the target frequency and the frequency droop control term; and the output voltage of the reactive power loop in the energy storage system is determined based on the target voltage, the voltage droop control term, and the voltage compensation term; wherein the voltage compensation term is determined based on the transmission impedance of the energy storage converter used in the black-start control method. Based on the output frequency of the active power loop and the output voltage of the reactive power loop in the energy storage system, a reference value for the output voltage used to achieve black start of the energy storage converter is determined, so as to control the output power of the energy storage converter.

2. The black-start control method according to claim 1, characterized in that, Determining the output frequency of the active power loop based on the target frequency and the frequency droop control term includes: determining the output frequency of the active power loop based on the target frequency, the frequency droop control term, and the frequency adjustment deviation term; wherein the frequency adjustment deviation term indicates the deviation between the actual output frequency of the active power loop and the average value of the actual output frequencies of all active power loops; and / or, The step of determining the output voltage of the reactive power loop based on the target voltage, voltage droop control term, and voltage compensation term includes: determining the output voltage of the reactive power loop based on the target voltage, voltage droop control term, voltage regulation deviation term, and voltage compensation term; wherein the voltage regulation deviation term is used to indicate the deviation between the actual output voltage of the reactive power loop and the average value of the actual output voltage of each reactive power loop.

3. The black-start control method according to claim 2, characterized in that, The frequency adjustment deviation term includes a frequency adjustment proportional term and a frequency adjustment integral term, and / or the voltage adjustment deviation term includes a voltage adjustment proportional term and a voltage adjustment integral term.

4. The black-start control method according to claim 1, characterized in that, At least two of the plurality of energy storage converters satisfy the following condition: The absolute value of the difference between the product of the reactive power and the transmission reactance of the two energy storage converters is less than a preset value, and the transmission reactance includes virtual reactance and line reactance. The absolute value of the difference between the product of the active power of the two energy storage converters and the transmission resistance is less than a preset value. The transmission resistance includes virtual resistance and line resistance. The absolute value of the difference between the ratio of the reactive power-voltage droop coefficient to the transmission reactance of the two energy storage converters is less than a preset value.

5. The black-start control method according to any one of claims 1-4, characterized in that, The voltage compensation term is determined based on the active power, line resistance, reactive power, line reactance, and output voltage of the energy storage converter.

6. The black-start control method according to claim 1, characterized in that, The frequency droop control term is determined based on the active power-frequency droop coefficient and the active power adjustment amount, wherein the active power adjustment amount is used to indicate the difference between the actual active power and the target active power, and / or, the voltage droop control term is determined based on the reactive power-voltage droop coefficient and the reactive power adjustment amount, wherein the reactive power adjustment amount is used to indicate the difference between the actual reactive power and the target reactive power.

7. The black-start control method according to claim 1, characterized in that, The determination of the reference value for the output voltage used to achieve black start of the energy storage converter based on the output frequency of the active power loop and the output voltage of the reactive power loop includes: Based on the output frequency of the active power loop and the output voltage of the reactive power loop, determine the target voltage reference value for achieving black start of the energy storage converter; The output voltage reference value for achieving black start of the energy storage converter is calculated based on the target voltage reference value for achieving black start of the energy storage converter, the output current of the energy storage converter, and the virtual impedance.

8. A control module, characterized in that, The control module is used to execute the method according to any one of claims 1 to 7.

9. An energy storage converter, characterized in that, The energy storage converter includes the control module as described in claim 8.

10. An energy storage system, characterized in that, The energy storage system includes multiple energy storage converters connected in parallel, and at least one energy storage converter includes the control module as described in claim 8.

11. An energy storage converter, characterized in that, The energy storage converter is used to perform the method as described in any one of claims 1 to 7.

12. A black-start control method, characterized in that, A controller applied in an energy storage system, the energy storage system including the controller and multiple energy storage converters connected in parallel, the method comprising: Send a black-start control command to a target number of energy storage converters so that the energy storage converters execute the method of any one of claims 1 to 7 to achieve black-start control of the energy storage converters; If the target number of energy storage converters successfully start up, the energy storage system is considered to have successfully started up.

13. The black-start control method according to claim 12, characterized in that, The process of determining the target quantity includes: The target quantity is determined by using the maximum power required for the black start process, the rate factor, and the individual power of the energy storage converter; The maximum power is calculated based on the maximum superimposed power of the lines, transformers and loads of the energy storage system during the black start process.

14. The black-start control method according to claim 12, characterized in that, For each energy storage converter, the process of determining whether the black start of the energy storage converter is successful includes: Upon receiving a successful power-on signal from the target number of energy storage converters, a voltage establishment command carrying a first preset voltage rise gradient is sent to the energy storage converters so that the energy storage converters determine the target voltage according to the first preset voltage rise gradient. Upon receiving a start-up completion signal from the energy storage converter, the energy storage converter is deemed to have successfully started from black; the start-up completion signal is generated after the energy storage converter raises its output voltage to the target voltage threshold.

15. A controller, characterized in that, The controller is used to perform the method according to any one of claims 12 to 14.

16. A chip, characterized in that, The chip is used to perform the method of any one of claims 1 to 7, or to perform the method of any one of claims 12 to 14.

17. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that is executed by a processor according to any one of claims 1 to 7 or 12 to 14.

18. A computer program product, characterized in that, The computer program product includes a computer program that is processed by a processor to perform the method of any one of claims 1 to 7 or 12 to 14.

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