Grid-forming energy storage system and control system, control method, and control device therefor

Abstract

The present application discloses a grid-forming energy storage system and a control system, control method, and control device therefor. The control system comprises: a first control system and a second control system, which are respectively connected to grid connection points of a power grid; and a controller, which is connected to the first control system and the second control system, and is used for acquiring a data refresh delay between the first control system and the second control system, and when switching from the first control system to the second control system, using a phase corresponding to the data refresh delay for the second control system for phase compensation control. In the present application, a phase deviation during switching is optimized, thereby achieving smooth redundant switching; fluctuations of the output voltage and power of a converter are controlled within a controllable range without changing the communication mode of a redundant system; in addition, the impact of pulse power in the redundant switching process is greatly reduced, and the service life of the grid-forming energy storage system is prolonged.

Description

Grid-type energy storage systems and their control systems, control methods, and control devices Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a grid-type energy storage system and its control system, control method and control device. Background Technology

[0002] To ensure the reliability of energy storage systems, their control systems employ a redundant design, typically a dual-system redundancy, consisting of a master system and a slave system. The system with valid outputs is called the master system, while the system with disabled outputs is called the slave system. In the event of a failure in the master system, a system switchover will be performed, and the original slave system will take over as the master system.

[0003] For grid-connected energy storage systems, due to the use of phase-locked loop (PLL)-free control, the phase and frequency of the control system depend on a virtual rotor motion equation. Only the phase of the master system is consistent with the external power grid; the slave system cannot accurately generate virtual speed and generator phase. Therefore, the slave system needs to rely on key state information such as control mode and unlock status transmitted from the master system for virtual synchronous machine control. Consequently, the reference phase received by the slave system deviates from the actual phase of the external power grid, generating step signals such as pulse power, which can cause significant power surges and other non-negligible impacts on the energy storage system. Summary of the Invention

[0004] In view of the above problems, the grid-type energy storage system and its control system, control method and control device provided in this application optimize the phase deviation during switching, thereby achieving smooth redundancy switching, controlling the converter output voltage and power fluctuations within a controllable range, without changing the communication method of the redundant system, and significantly reducing the impact of pulse power during redundancy switching, thus extending the service life of the grid-type energy storage system.

[0005] To address the aforementioned problems, this application provides a control system for a grid-connected energy storage system, comprising: a first control system and a second control system, respectively connected to the grid connection point; and a controller connected to both the first and second control systems, configured to acquire the data refresh delay between the first and second control systems, and, when switching from the first control system to the second control system, use the phase corresponding to the data refresh delay for phase compensation control in the second control system. In this embodiment, by acquiring the data refresh delay between the first and second control systems and using the phase corresponding to the data refresh delay for phase compensation control in the second control system when switching from the first control system to the second control system, the phase deviation during switching is optimized, thereby achieving smooth redundancy switching. This keeps the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system, while significantly reducing the impact of pulse power during redundancy switching and extending the service life of the grid-connected energy storage system.

[0006] In some embodiments, the controller is configured to superimpose the phase corresponding to the data refresh delay with the phase of the first control system for phase control by the second control system; or the second control system superimposes the phase corresponding to the data refresh delay with the phase of the first control system for phase control; or the second control system uses the phase corresponding to the data refresh delay for phase compensation control. By superimposing the phase corresponding to the data refresh delay with the phase of the first control system for phase control by the second control system, or by using the phase corresponding to the data refresh delay for phase compensation control, the phase deviation during switching is optimized, thereby achieving smooth redundant switching and controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system.

[0007] In some embodiments, the data refresh delay is located within a time interval, where the minimum value of the time interval is the physical delay, and the maximum value is the sum of the physical delay and the program execution cycle of the first control system itself. By analyzing and determining that the data refresh delay is located within a time interval, the data refresh delay can be accurately determined to optimize the phase deviation during switching, thereby achieving smooth redundant switching and controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system.

[0008] In some embodiments, the control system further includes a timer connected to the controller, used to measure the measurement time from when the second control system receives a system synchronization signal from the first control system to when the second control system receives a system switching signal, as the data refresh delay. Measuring the data refresh delay using the timer, and actually measuring the data refresh delay, is used to optimize the phase deviation during switching, achieving phase deviation-free compensation, thereby realizing redundant smooth switching and controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system.

[0009] In some embodiments, the second control system includes a timer connected to the controller, used to measure the time from when the second control system receives a system synchronization signal from the first control system to when the second control system receives a system switching signal, as the data refresh delay. Measuring the data refresh delay using the timer, and actually measuring the data refresh delay, is used to optimize the phase deviation during switching, achieving phase deviation-free compensation, thereby realizing redundant smooth switching and controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system.

[0010] In some embodiments, the data refresh delay is the midpoint value of the time interval. The data refresh delay is determined by estimating it from the analyzed time interval. This is used to optimize phase deviation during switching, achieving phase deviation-free compensation, thereby enabling smooth redundant switching and controlling converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system.

[0011] In some embodiments, the phase corresponding to the data refresh delay is the data refresh delay divided by the system period of the grid-type energy storage system, and then multiplied by 360 degrees. By obtaining the phase corresponding to the data refresh delay, it is used to optimize the phase deviation during switching, achieving phase deviation-free compensation, thereby realizing smooth redundancy switching and controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system.

[0012] In some embodiments, the phase of the first control system is received by the second control system from the first control system. By receiving the phase from the first control system, the second control system performs phase control or phase compensation control, optimizes the phase deviation during switching, thereby achieving smooth redundancy switching and controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system.

[0013] To address the aforementioned issues, this application provides a grid-connected energy storage system, including the aforementioned control system and a power grid connected to the control system via a grid connection point.

[0014] To address the aforementioned problems, this application provides a control method for a grid-connected energy storage system. The grid-connected energy storage system includes a first control system and a second control system, each connected to a grid connection point. The control method includes: acquiring a data refresh delay between the first control system and the second control system; and when switching from the first control system to the second control system, using the phase corresponding to the data refresh delay for phase compensation control in the second control system.

[0015] In some embodiments, using the phase corresponding to the data refresh delay for phase compensation control in the second control system includes: superimposing the phase corresponding to the data refresh delay with the phase of the first control system for phase control in the second control system.

[0016] To address the aforementioned problems, this application provides a control device for a grid-connected energy storage system. The grid-connected energy storage system includes a first control system and a second control system, each connected to a grid connection point. The control method includes: a data refresh delay acquisition module, used to acquire the data refresh delay between the first control system and the second control system when switching from the first control system to the second control system; and a phase compensation control module, used to apply the phase corresponding to the data refresh delay to the second control system for phase compensation control.

[0017] By acquiring the data refresh delay between the first and second control systems, and using the phase corresponding to the data refresh delay for phase compensation control in the second control system when switching from the first to the second control system, the phase deviation during switching is optimized, thereby achieving smooth redundant switching. This controls the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system. At the same time, it significantly reduces the impact of pulse power during redundant switching and extends the service life of the grid-type energy storage system. Attached Figure Description

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0019] Figure 1 is a schematic diagram of the control system of the grid-type energy storage system according to an embodiment of this application;

[0020] Figure 2 is a schematic diagram of redundancy switching of the control system of the grid-type energy storage system according to an embodiment of this application;

[0021] Figure 3 is a control equivalent circuit diagram of a grid-type energy storage system according to an embodiment of this application;

[0022] Figure 4 is a flowchart of a control method for a grid-type energy storage system according to an embodiment of this application;

[0023] Figure 5 is a comparison diagram of the instantaneous power of the redundancy switching of the control system of the grid-type energy storage system according to an embodiment of this application;

[0024] Figure 6 is a comparison diagram of the instantaneous power of the redundancy switching of the control system of the grid-type energy storage system according to an embodiment of this application;

[0025] Figure 7 is a schematic diagram of the structure of a control device for a grid-type energy storage system according to an embodiment of this application;

[0026] Figure 8 is a schematic diagram of the structure of an electronic device according to an embodiment of this application;

[0027] Figure 9 is a schematic diagram of the structure of a computer-readable storage medium according to an embodiment of this application. Embodiments of the present invention

[0028] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0030] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0031] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0032] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0033] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0034] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0035] In the dual-system redundancy design of a grid-connected energy storage system, due to the use of phase-locked loop (PLL)-free control, the phase and frequency of the control system depend on a virtual rotor motion equation. Only the phase of the master system is consistent with the external power grid; the slave system cannot accurately generate virtual speed and generator phase. Therefore, the slave system needs to rely on key status information such as control mode and unlock status transmitted from the master system for virtual synchronous machine control. This involves data refresh between systems, meaning the slave system receives data from the master system in real time for updating. Due to the refresh delay, the reference phase received by the slave system deviates from the actual phase of the external power grid, generating step signals such as pulse power, which can cause significant power surges and other non-negligible impacts on the energy storage system.

[0036] In view of this, the control system of the grid-type energy storage system provided in this application is equipped with a controller, wherein the controller is used to obtain the data refresh delay between the first control system and the second control system, and when switching from the first control system to the second control system, the phase corresponding to the data refresh delay is used for phase compensation control of the second control system to optimize the phase deviation during switching, thereby realizing redundant smooth switching and controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system.

[0037] Please refer to Figure 1, which is a schematic diagram of the control system of a grid-connected energy storage system according to an embodiment of this application. The control system 10 includes a first control system 11, a second control system 12, and a controller 13, all connected to the grid connection point. The controller 13 is connected to the first control system 11 and the second control system 12, and is used to obtain the data refresh delay between the first control system 11 and the second control system 12. When switching from the first control system 11 to the second control system 12, the controller 13 uses the phase corresponding to the data refresh delay for phase compensation control in the second control system 12.

[0038] Grid-based energy storage systems serve as voltage sources, including but not limited to grid-based converters, step-up transformers, and power lines. They can simulate synchronous generator sets, internally set voltage parameters, and exchange active and reactive power with the grid by controlling the phase and amplitude of the converter output, thereby outputting stable voltage and frequency.

[0039] The first control system 11 and the second control system 12 are redundantly designed, also known as redundant systems. The first control system 11 is the master system and the second control system 12 is the slave system.

[0040] The first control system 11 or the second control system 12 mainly includes a pole control system, a valve control system, and a sub-module-level control system to achieve various functions. The pole control system generates modulation wave commands based on the control objectives of the DC system. The valve control system receives these modulation wave commands, parses them, and issues switching commands to each sub-module. The sub-module-level control system controls the switching on and off of the corresponding IGBT devices, realizing the connection or disconnection of the DC capacitor, and fitting AC voltages with different amplitudes and phase angles. Of course, the first control system 11 or the second control system 12, i.e., the master system or slave system, may also include other modules, such as a sampling module and a digital-to-analog converter module.

[0041] The controller 13 may be a logic device connected to the first control system 11 and the second control system 12 to obtain the data refresh delay between the first control system 11 and the second control system 12.

[0042] Please refer to Figure 2, which is a schematic diagram of redundancy switching of the control system of a grid-type energy storage system according to an embodiment of this application. The data refresh delay is the time from when the second control system 12 receives the system synchronization signal from the first control system 11 to when the second control system 12 receives the system switching signal. The system synchronization signal is used to indicate that the second control system 12 receives key status information such as the corresponding control mode and unlock status from the first control system 11, including the phase of the first control system 11. The system switching signal is used to indicate the switch from the first control system 11 to the second control system 12, so that the second control system 12 can be used for control. The system switching signal may be a signal generated when the first control system 11 fails.

[0043] The phase corresponding to the data refresh delay can be data refresh delay / system period × 360°, that is, the data refresh delay is divided by the system period of the grid-type energy storage system and multiplied by 360 degrees, where the system period is 20ms. When switching from the first control system 11 to the second control system 12, the controller 13 uses the phase corresponding to the data refresh delay for phase compensation control in the second control system 12. For example, the controller 13 superimposes the phase corresponding to the data refresh delay with the phase of the first control system 11 for phase compensation control in the second control system 12.

[0044] In this embodiment, by obtaining the data refresh delay between the first control system and the second control system, and when switching from the first control system to the second control system, the phase corresponding to the data refresh delay is used for phase compensation control of the second control system to optimize the phase deviation during switching, thereby achieving smooth redundancy switching, controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system, and significantly reducing the impact of pulse power during redundancy switching, thus extending the service life of the grid-type energy storage system.

[0045] In some embodiments, the controller 13 is used to superimpose the phase corresponding to the data refresh delay with the phase of the first control system 11 for phase control by the second control system 12, or the second control system 12 superimposes the phase corresponding to the data refresh delay with the phase of the first control system 11 for phase control, or the second control system 12 uses the phase corresponding to the data refresh delay for phase compensation control.

[0046] To facilitate understanding of the phase control or phase compensation control in this application, the control equivalent circuit of the grid-type energy storage system involved in the embodiments of this application will be described below. Please refer to Figure 3, which is a control equivalent circuit diagram of the grid-type energy storage system involved in the embodiments of this application. The control equivalent circuit is used for the first control system 11 and the second control system 12. When the first control system 11 performs control, it internally sets voltage parameters and controls the grid-type converter to output corresponding phase and amplitude, exchanging active and reactive power with the grid, thereby outputting a stable voltage and frequency. That is, the first control system 11 controls the output phase θref to perform corresponding control. When switching to the second control system 12, the second control system 12 also uses the control equivalent circuit for control.

[0047] The controller 13 is connected to the first control system 11 and can receive the phase θref from the first control system 11. Then, it superimposes the phase corresponding to the data refresh delay with the phase θref from the first control system 11 for phase control by the second control system 12. At this time, the second control system 12 controls the converter to output the superimposed phase, directly controlling the converter according to the superimposed phase, exchanging active and reactive power with the grid, thereby outputting a stable voltage and frequency.

[0048] Optionally, the second control system 12 receives the phase from the first control system 11, superimposes it with the phase corresponding to the data refresh delay, and performs phase control. At this time, the second control system 12 controls the converter to output the superimposed phase, directly controls it according to the superimposed phase, and exchanges active and reactive power with the grid, thereby outputting a stable voltage and frequency.

[0049] Optionally, the second control system 12 utilizes the phase corresponding to the data refresh delay for phase compensation control. A delay compensation stage is added to the active / DC voltage control section, specifically to the outer loop control circuit of the active / DC voltage control section. This enables the converter to output the corresponding phase, allowing for active and reactive power exchange with the grid, thereby outputting a stable voltage and frequency.

[0050] In this embodiment, the phase corresponding to the data refresh delay is superimposed with the phase of the first control system for phase control by the second control system, or the phase corresponding to the data refresh delay is used for phase compensation control to optimize the phase deviation during switching, thereby achieving redundant smooth switching and controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system.

[0051] In some embodiments, the data refresh delay is located within a time interval, wherein the minimum value of the time interval is the physical delay, and the maximum value is the sum of the physical delay and the program execution cycle of the first control system 11 itself.

[0052] Referring to Figure 2, the first control system 11 and the second control system 12 use asynchronous communication. The actual delay in signal transmission between the systems caused by asynchronous communication is not a fixed value; its time interval is Δt2 ~ Δt2 + Δt, where Δt2 is the physical delay in signal transmission between the first control system 11 and the second control system 12, caused by the communication link between them, and Δt is the program execution cycle of the first control system 11 itself. Δt2 can be between Δt and 2Δt.

[0053] The data refresh delay is the time from when the second control system 12 receives the system synchronization signal from the first control system 11 to when the second control system 12 receives the system switching signal. It can be seen that when the second control system 12 receives the corresponding system synchronization signal from the first control system 11, this causes the actual delay in signal transmission between the systems. In other words, the data refresh delay is also the actual delay in signal transmission between the systems. Similarly, its time interval is Δt2 ~ Δt2 + Δt, where Δt2 is the physical delay in signal transmission between the first control system 11 and the second control system 12, caused by the communication link between them, and Δt is the program execution cycle of the first control system 11 itself. Δt2 can be between Δt and 2Δt.

[0054] In this embodiment, by analyzing the data refresh delay within the time interval, the data refresh delay is accurately determined and used to optimize the phase deviation during switching, thereby achieving smooth switching of redundancy and controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system.

[0055] In some embodiments, the second control system 12 includes a timer connected to the controller 13, used to measure the measurement time from when the second control system 12 receives a system synchronization signal from the first control system 11 to when the second control system 12 receives a system switching signal, as a data refresh delay.

[0056] The second control system 12 includes a timer, which can be implemented by software control on the second control system 12, for example, by a system timer.

[0057] The data refresh delay is the time from when the second control system 12 receives the system synchronization signal from the first control system 11 to when the second control system 12 receives the system switching signal. It can be seen that the second control system 12 can transmit the corresponding system synchronization signal received from the first control system 11 and the system switching signal received by the second control system 12 to the timer internally.

[0058] In this embodiment, the data refresh delay is measured by a timer. The actual measured data refresh delay is used to optimize the phase deviation during switching, achieve phase deviation-free compensation, thereby realizing smooth switching of redundancy and controlling the output voltage and power fluctuations of the converter within a controllable range without changing the communication method of the redundant system.

[0059] In some embodiments, the control system of the grid-type energy storage system further includes a timer connected to the controller 13, used to measure the measurement time from when the second control system 12 receives the system synchronization signal from the first control system 11 to when the second control system 12 receives the system switching signal, as a data refresh delay.

[0060] The control system of the grid-type energy storage system also includes a timer, which can be implemented by physical hardware. It is connected to the controller 13 to measure the data refresh delay. The data refresh delay is the time from when the second control system 12 receives the system synchronization signal from the first control system 11 to when the second control system 12 receives the system switching signal. It can be seen that the second control system 12 can receive the corresponding system synchronization signal from the first control system 11 and the second control system 12 can receive the system switching signal from the first control system 11. Both can be transmitted to the timer by the controller 13.

[0061] In this embodiment, the data refresh delay is measured by a timer. The actual measured data refresh delay is used to optimize the phase deviation during switching, achieve phase deviation-free compensation, thereby realizing smooth switching of redundancy and controlling the output voltage and power fluctuations of the converter within a controllable range without changing the communication method of the redundant system.

[0062] In some embodiments, the data refresh delay is the midpoint of the time interval.

[0063] The data refresh delay is the time from when the second control system 12 receives the system synchronization signal from the first control system 11 to when the second control system 12 receives the system switching signal. It can be seen that when the second control system 12 receives the corresponding system synchronization signal from the first control system 11, it causes the actual delay in signal transmission between the systems. In other words, the data refresh delay is also the actual delay in signal transmission between the systems. Similarly, its time interval is Δt2 ~ Δt2+Δt, where Δt2 is the physical delay in signal transmission between the first control system 11 and the second control system 12, which is caused by the communication link in signal transmission between the first control system 11 and the second control system 12, and Δt is the program running cycle of the first control system 11 itself.

[0064] If the data refresh delay is the midpoint of the time interval, then the data refresh delay is Δt² + 0.5Δt. Of course, in other embodiments, the data refresh delay can also be other points in the time interval, such as Δt² + 0.7Δt, as long as the data refresh delay falls within that time interval.

[0065] In this embodiment, the data refresh delay is estimated from the time interval obtained by analysis to determine the data refresh delay, which is used to optimize the phase deviation during switching, realize phase deviation-free compensation, thereby achieving smooth switching of redundancy, and controlling the output voltage and power fluctuation of the converter within a controllable range without changing the communication method of the redundant system.

[0066] In some embodiments, the phase corresponding to the data refresh delay is the data refresh delay divided by the system period of the grid-type energy storage system and multiplied by 360 degrees.

[0067] The phase corresponding to the data refresh delay can be data refresh delay / system period × 360°, that is, the data refresh delay is divided by the system period of the grid-type energy storage system and multiplied by 360 degrees, where the system period is 20ms.

[0068] In this embodiment, by obtaining the phase corresponding to the data refresh delay, it is used to optimize the phase deviation during switching, thereby achieving phase deviation-free compensation and realizing redundant smooth switching. This controls the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system.

[0069] In some embodiments, the phase of the first control system 11 is received by the second control system 12 from the first control system 11.

[0070] The second control system 12 receives key status information such as the control mode and unlock status from the first control system 11, including the phase of the first control system 11.

[0071] In this embodiment, the second control system receives the phase from the first control system and implements phase control or phase compensation control to optimize the phase deviation during switching, thereby achieving smooth redundant switching and controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system.

[0072] This application further proposes a grid-based energy storage system, including the aforementioned control system 10 and a power grid connected to the control system 10 via a grid connection point. Based on this, the phase deviation during switching is optimized, thereby achieving smooth redundancy switching, controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system, and significantly reducing the impact of pulse power during redundancy switching, thus extending the service life of the grid-based energy storage system.

[0073] Please refer to Figure 4, which is a flowchart of a control method for a grid-connected energy storage system according to an embodiment of this application. The grid-connected energy storage system includes a first control system and a second control system respectively connected to the grid connection point. The control method includes: S41: obtaining the data refresh delay between the first control system and the second control system; S42: when switching from the first control system to the second control system, using the phase corresponding to the data refresh delay for phase compensation control of the second control system.

[0074] In this embodiment, by obtaining the data refresh delay between the first control system and the second control system, and when switching from the first control system to the second control system, the phase corresponding to the data refresh delay is used for phase compensation control of the second control system to optimize the phase deviation during switching, thereby achieving smooth redundancy switching, controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system, and significantly reducing the impact of pulse power during redundancy switching, thus extending the service life of the grid-type energy storage system.

[0075] In some embodiments, step S42, using the phase corresponding to the data refresh delay for phase control in the second control system, includes: superimposing the phase corresponding to the data refresh delay with the phase of the first control system for phase control in the second control system.

[0076] In this embodiment, the phase corresponding to the data refresh delay is superimposed with the phase of the first control system for phase control by the second control system. This optimizes the phase deviation during switching, thereby achieving smooth switching of redundancy and controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system.

[0077] In some embodiments, in the redundancy switching strategy of the control system of the grid-type energy storage system shown in Figure 1, when the system switches, the data refresh delay between the redundant systems is obtained, that is, the data refresh delay between the first control system and the second control system, and the phase corresponding to the data refresh delay is used for phase compensation control of the switched system (i.e., the second control system).

[0078] Theoretically, the data refresh delay between redundant systems lies within the interval Δt2 ~ Δt2 + Δt, where Δt2 is the physical delay of signal transmission between the first and second control systems, caused by the communication link between them, and Δt is the program execution cycle of the first control system itself. Specifically, the data refresh delay is the time from when the second control system receives the system synchronization signal from the first control system to when it receives the system switching signal. It can be seen that when the second control system receives the corresponding system synchronization signal from the first control system, this causes the actual delay in signal transmission between the systems. In other words, the data refresh delay is also the actual delay in signal transmission between the systems, and its time interval is Δt2 ~ Δt2 + Δt. The phase corresponding to the data refresh delay can be calculated as data refresh delay / system period × 360°, that is, the data refresh delay is divided by the system period of the grid-type energy storage system and multiplied by 360 degrees, where the system period is 20ms.

[0079] When performing redundancy switching, the methods for obtaining the data refresh delay between redundant systems can include the following:

[0080] Option 1: Add a timing mechanism, such as a timer, to measure the actual data refresh delay, and obtain the corresponding phase based on the data refresh delay = measurement delay / 20ms × 360°.

[0081] When using Scheme 1, the power diagram at the moment of redundancy switching is shown in Figure 5(a), where there is no fluctuation in active power. To facilitate understanding of the advantages of the redundancy switching strategy using Scheme 1, Figure 5(b) shows the redundancy switching strategy without considering data refresh delay, with a maximum active power deviation of -8.9MW. The comparison shows that the redundancy switching strategy using Scheme 1 optimizes the phase deviation during switching, thereby achieving smooth redundancy switching and controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system. At the same time, it significantly reduces the impact of pulse power during redundancy switching.

[0082] It should be noted that the redundancy switching strategies in Figure 5 are all under the condition of controlling P=100MW.

[0083] Option 2: Take the midpoint value of the interval △t2 ~ △t2+△t, i.e. △t2+0.5△t, estimate the data refresh delay, and obtain the corresponding phase based on the data refresh delay = estimated delay / 20ms×360°.

[0084] When using Scheme 2, the instantaneous power diagram during redundancy switching is shown in Figure 6(a), with a maximum active power deviation of 5.5MW. To better understand the advantages of the redundancy switching strategy using Scheme 2, Figure 6(b) shows the redundancy switching strategy without considering data refresh delay, with a maximum active power deviation of -8.9MW. The comparison shows that the redundancy switching strategy using Scheme 2 optimizes the phase deviation during switching, thereby achieving smooth redundancy switching, controlling the converter output voltage and power fluctuations within a controllable range, without changing the communication method of the redundant system, and significantly reducing the impact of pulse power during redundancy switching.

[0085] It should be noted that the redundancy switching strategies in Figure 6 are all under the condition of controlling P=100MW.

[0086] Please refer to Figure 7, which is a schematic diagram of a control device 70 for a grid-connected energy storage system according to an embodiment of this application. The grid-connected energy storage system includes a first control system and a second control system connected to the grid connection point. The control device 70 includes a data refresh delay acquisition module 71 and a phase compensation control module 72. The data refresh delay acquisition module 71 is used to acquire the data refresh delay between the first and second control systems when switching from the first control system to the second control system. The phase compensation control module 72 is used to apply the phase corresponding to the data refresh delay to the second control system for phase compensation control.

[0087] In this embodiment, when switching from the first control system to the second control system, the data refresh delay between the first control system and the second control system is obtained, and the phase corresponding to the data refresh delay is used for phase compensation control of the second control system to optimize the phase deviation during switching. This achieves smooth redundancy switching, controls the converter output voltage and power fluctuations within a controllable range, and does not require changing the communication method of the redundant system. At the same time, it significantly reduces the impact of pulse power during redundancy switching and extends the service life of the grid-type energy storage system.

[0088] In some embodiments, the phase compensation control module 72 is used to superimpose the phase corresponding to the data refresh delay with the phase of the first control system for phase control by the second control system.

[0089] In this embodiment, the phase corresponding to the data refresh delay is superimposed with the phase of the first control system for phase control by the second control system. This optimizes the phase deviation during switching, thereby achieving smooth switching of redundancy and controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system.

[0090] Please refer to Figure 8, which is a schematic diagram of the structure of an electronic device according to an embodiment of this application. The electronic device 80 includes a memory 81 and a processor 82. The processor 82 is used to execute program instructions stored in the memory 81 to implement the steps in any of the above-described embodiments of the control method for a grid-type energy storage system. In a specific implementation scenario, the electronic device 80 may include, but is not limited to, a microcomputer or a server. Furthermore, the electronic device 80 may also include a laptop computer, tablet computer, or other similar device; no further limitations are imposed here.

[0091] Specifically, processor 82 is used to control itself and memory 81 to implement the steps in any of the control method embodiments of the above-described grid-type energy storage system. Processor 82 can also be referred to as a CPU (Central Processing Unit). Processor 82 may be an integrated circuit chip with signal processing capabilities. Processor 82 can also be a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. A general-purpose processor can be a microprocessor or any conventional processor. Furthermore, processor 82 can be implemented using integrated circuit chips.

[0092] In this embodiment, by obtaining the data refresh delay between the first control system and the second control system, and when switching from the first control system to the second control system, the phase corresponding to the data refresh delay is used for phase compensation control of the second control system to optimize the phase deviation during switching, thereby achieving smooth redundancy switching, controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system, and significantly reducing the impact of pulse power during redundancy switching, thus extending the service life of the grid-type energy storage system.

[0093] Please refer to Figure 9, which is a schematic diagram of the structure of a computer-readable storage medium according to an embodiment of this application. The computer-readable storage medium 90 stores program instructions 901 thereon. When the program instructions 901 are executed by a processor, they implement the steps in any of the above-described embodiments of the control method for a grid-type energy storage system.

[0094] In this embodiment, by obtaining the data refresh delay between the first control system and the second control system, and when switching from the first control system to the second control system, the phase corresponding to the data refresh delay is used for phase compensation control of the second control system to optimize the phase deviation during switching, thereby achieving smooth redundancy switching, controlling the converter output voltage and power fluctuations within a controllable range without changing the communication method of the redundant system, and significantly reducing the impact of pulse power during redundancy switching, thus extending the service life of the grid-type energy storage system.

[0095] In some embodiments, the functions or modules of the apparatus provided in this disclosure can be used to perform the methods described in the above method embodiments. The specific implementation can be referred to the description of the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0096] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A control system, wherein, The control system is used in a grid-type energy storage system and includes: The first and second control systems are respectively connected to the grid connection point; The controller, connected to the first control system and the second control system, is used to obtain the data refresh delay between the first control system and the second control system, and when switching from the first control system to the second control system, uses the phase corresponding to the data refresh delay to perform phase compensation control on the second control system.

2. The control system of claim 1, wherein, The controller is used to superimpose the phase corresponding to the data refresh delay with the phase of the first control system for phase control by the second control system.

3. The control system of claim 1, wherein, The second control system superimposes the phase corresponding to the data refresh delay with the phase of the first control system to perform phase control.

4. The control system of claim 1, wherein, The second control system uses the phase corresponding to the data refresh delay to perform phase compensation control.

5. The control system of any one of claims 1-4, wherein, The data refresh delay is located within a time interval, where the minimum value of the time interval is the physical delay and the maximum value is the sum of the physical delay and the program execution cycle of the first control system itself.

6. The control system of any one of claims 1-5, wherein, Also includes: A timer, connected to the controller, is used to measure the time from when the second control system receives a system synchronization signal from the first control system to when the second control system receives a system switching signal, and this time is used as the data refresh delay.

7. The control system of any one of claims 1-5, wherein, The second control system includes: A timer, connected to the controller, is used to measure the time from when the second control system receives a system synchronization signal from the first control system to when the second control system receives a system switching signal, and this time is used as the data refresh delay.

8. The control system of claim 5, wherein, The data refresh delay is the midpoint value of the time interval.

9. The control system of any one of claims 1-8, wherein, The phase corresponding to the data refresh delay is the data refresh delay divided by the system period of the grid-type energy storage system, and then multiplied by 360 degrees.

10. The control system according to any one of claims 2-9, wherein, The phase of the first control system is received by the second control system from the first control system.

11. The control system of any one of claims 2-10, wherein, The data refresh delay is the time from when the second control system receives the system synchronization signal from the first control system to when the second control system receives the system switching signal, wherein the system synchronization signal is used to indicate that the second control system receives the phase of the first control system from the first control system, and the system switching signal is used to indicate switching from the first control system to the second control system so that the second control system can be used for control.

12. The control system of claim 11, wherein, The system switching signal is generated when the first control system malfunctions.

13. A grid-forming energy storage system, wherein, It includes the control system as described in any one of claims 1-12 and the power grid connected to the control system via a power grid connection point.

14. A control method, wherein, For a grid-connected energy storage system, the grid-connected energy storage system includes a first control system and a second control system respectively connected to the grid connection point; the control method includes: Obtain the data refresh delay between the first control system and the second control system; When switching from the first control system to the second control system, the phase corresponding to the data refresh delay is used for phase compensation control in the second control system.

15. The control method according to claim 14, wherein The step of using the phase corresponding to the data refresh delay for phase compensation control in the second control system includes: The phase corresponding to the data refresh delay is superimposed with the phase of the first control system for phase control by the second control system.

16. A control device, wherein, The control device is used in a grid-connected energy storage system, which includes a first control system and a second control system respectively connected to the grid connection point; the control device includes: The data refresh delay acquisition module is used to acquire the data refresh delay between the first control system and the second control system when switching from the first control system to the second control system; The phase compensation control module is used to use the phase corresponding to the data refresh delay for phase compensation control in the second control system.

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