Frequency modulation switching method, device, equipment and system for hybrid energy storage

Abstract

The invention provides a frequency modulation switching method, device, equipment and system for hybrid energy storage, and relates to the technical field of power grid frequency modulation. The method comprises the steps of obtaining a real-time SOC value of the flywheel energy storage device in a power grid frequency modulation process of the flywheel energy storage device; determining the remaining available time of the flywheel energy storage device based on the real-time SOC value; when the remaining available time reaches a set time threshold value, the battery energy storage device is controlled to start participating in power grid frequency modulation; and correspondingly reducing the real-time flywheel frequency modulation power of the flywheel energy storage device based on the real-time battery frequency modulation power of the battery energy storage device until the real-time battery frequency modulation power of the battery energy storage device reaches the frequency modulation power required by the current power grid. According to the invention, seamless switching between the flywheel energy storage device and the battery energy storage device can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power grid frequency modulation, and particularly relates to a hybrid energy storage frequency modulation switching method, device, equipment and system. BACKGROUND

[0002] In the field of power grid primary frequency modulation, hybrid energy storage systems have attracted extensive attention due to their comprehensive performance advantages. Such systems are usually composed of different types of energy storage elements, among which the combination of flywheel energy storage devices and battery energy storage devices is particularly typical. Flywheel energy storage has the characteristics of rapid power response, frequent charging and discharging, and almost no influence of cycle times, while battery energy storage can provide relatively persistent energy support.

[0003] However, the energy storage capacity of flywheel energy storage devices is relatively limited, and in the process of continuously supporting power grid frequency modulation, the state of charge (SOC) thereof will quickly decrease to the lower limit value or increase to the upper limit value, making it difficult to support the complete frequency modulation process alone. Although battery energy storage devices have sufficient energy reserves, the frequent power switching and charging and discharging cycles will accelerate the aging of the battery energy storage devices due to their chemical properties, seriously affecting the service life. When the system needs to switch from the flywheel energy storage dominant mode to the battery energy storage support mode, improper switching strategy may easily lead to sudden changes or interruptions in power output, thereby affecting the stability of the power grid frequency.

[0004] Therefore, in the process of power grid primary frequency modulation, how to control the flywheel energy storage device and the battery energy storage device to cooperate with each other to achieve seamless switching is a problem to be solved at present. SUMMARY

[0005] Embodiments of the present application provide a hybrid energy storage frequency modulation switching method, device, equipment and system to control the flywheel energy storage device and the battery energy storage device to cooperate with each other to achieve seamless switching.

[0006] In a first aspect, the embodiments of the present application provide a hybrid energy storage frequency modulation switching method, comprising: In the process of flywheel energy storage device performing power grid frequency modulation, an real-time SOC value of the flywheel energy storage device is acquired; Based on the real-time SOC value, a remaining available time of the flywheel energy storage device is determined; When the remaining available time reaches a set time threshold, a battery energy storage device is controlled to start participating in power grid frequency modulation; Based on a real-time battery frequency modulation power of the battery energy storage device, a real-time flywheel frequency modulation power of the flywheel energy storage device is correspondingly reduced until the real-time battery frequency modulation power of the battery energy storage device reaches the frequency modulation power required by the current power grid.

[0007] In a possible implementation, the controlling the battery energy storage device to start participating in grid frequency modulation when the remaining available time reaches a set time threshold comprises: determining the set time threshold based on a required frequency modulation power of a current grid; controlling the battery energy storage device to start when the remaining available time reaches the set time threshold based on the required frequency modulation power of the current grid.

[0008] In a possible implementation, the determining the set time threshold based on the required frequency modulation power of the current grid comprises: obtaining a preset query table; the query table contains a required start time of the battery energy storage device from receiving a start instruction to stably output different frequency modulation powers; determining the start time of the battery energy storage device based on the query table and the required frequency modulation power of the current grid; determining the set time threshold based on the start time and a preset safety margin time.

[0009] In a possible implementation, the corresponding reducing the real-time flywheel frequency modulation power of the flywheel energy storage device based on the real-time battery frequency modulation power of the battery energy storage device comprises: obtaining the real-time battery frequency modulation power of the battery energy storage device during a start process of the battery energy storage device; determining a required frequency modulation power currently required to be provided by the flywheel energy storage device based on a difference between the required frequency modulation power of the current grid and the real-time battery frequency modulation power; reducing the real-time flywheel frequency modulation power of the flywheel energy storage device according to the required frequency modulation power currently required to be provided by the flywheel energy storage device.

[0010] In a possible implementation, the determining the remaining available time of the flywheel energy storage device based on the real-time SOC value comprises: obtaining an upper limit value of an SOC of the flywheel energy storage device, a lower limit value of the SOC, and an energy capacity; when the flywheel energy storage device is in a discharging state, determining a remaining available energy of the flywheel energy storage device based on a difference between the real-time SOC value and the lower limit value of the SOC and the energy capacity; when the flywheel energy storage device is in a charging state, determining a remaining available energy of the flywheel energy storage device based on a difference between the upper limit value of the SOC and the real-time SOC value and the energy capacity; determining the remaining available time of the flywheel energy storage device based on the remaining available energy.

[0011] In a possible implementation, the determining the remaining available time of the flywheel energy storage device based on the remaining available energy comprises: obtaining a real-time flywheel frequency modulation power of the flywheel energy storage device; determining the remaining available time of the flywheel energy storage device based on a ratio of the remaining available energy to the real-time flywheel frequency modulation power.

[0012] In a second aspect, an embodiment of the present application provides a hybrid energy storage frequency modulation switching device, comprising: an obtaining module configured to obtain a real-time SOC value of a flywheel energy storage device during grid frequency modulation performed by the flywheel energy storage device; a calculating module configured to determine a remaining available time of the flywheel energy storage device based on the real-time SOC value; a switching module configured to: control a battery energy storage device to start participating in grid frequency modulation when the remaining available time reaches a set time threshold; correspondingly reduce a real-time flywheel frequency modulation power of the flywheel energy storage device based on a real-time battery frequency modulation power of the battery energy storage device, until the real-time battery frequency modulation power of the battery energy storage device reaches a frequency modulation power required by a current grid.

[0013] In a third aspect, an embodiment of the present application provides a switching device, comprising a memory and a processor, the memory stores a computer program, and the processor implements the method in the first aspect or any possible implementation manner of the first aspect when executing the computer program.

[0014] In a fourth aspect, an embodiment of the present application provides a hybrid energy storage system, comprising a flywheel energy storage device, a battery energy storage device, and the switching device in the third aspect.

[0015] In a fifth aspect, an embodiment of the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the method in the first aspect or any possible implementation manner of the first aspect.

[0016] In the embodiment of the present application, by monitoring the real-time SOC value of the flywheel energy storage device in real time and estimating the remaining available time, the battery energy storage device can be started in time to participate in frequency modulation before the flywheel energy is about to be exhausted (or before the flywheel energy is about to be full). The process ensures smooth connection of the power source of grid frequency modulation, effectively avoids the interruption of frequency modulation power due to insufficient support of flywheel alone, and thus guarantees the stability of grid frequency. Moreover, after the battery energy storage device is started, the real-time flywheel frequency modulation power of the flywheel energy storage device is correspondingly reduced according to the real-time battery frequency modulation power output, realizing the collaborative output between the two energy storage devices. The control method makes the total frequency modulation power stable during the switching process, avoids the secondary impact on the grid caused by sudden change of frequency modulation power, and realizes seamless switching from the flywheel energy storage device to the battery energy storage device. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is the application scenario diagram of the frequency modulation switching method of the hybrid energy storage provided by the embodiment of the present application; Figure 2 is a structural schematic diagram of the hybrid energy storage system provided by the embodiment of the present application; Figure 3 is the implementation flowchart of the frequency modulation switching method of the hybrid energy storage provided by the embodiment of the present application; Figure 4 is a structural schematic diagram of the frequency modulation switching device of the hybrid energy storage provided by the embodiment of the present application; Figure 5 is a schematic diagram of the switching device provided by the embodiment of the present application. DETAILED DESCRIPTION

[0018] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0019] When the hybrid energy storage system composed of flywheel energy storage and battery energy storage participates in grid frequency modulation, the flywheel energy storage device cannot support the entire frequency modulation process alone, and needs to be switched to the battery energy storage to continue the subsequent frequency modulation process. When the hybrid energy storage system needs to switch from flywheel energy storage to battery energy storage to support frequency modulation, if the switching strategy between the flywheel energy storage and the battery energy storage is improper, it is easy to cause sudden change or interruption of power output, and thus affect the stability of grid frequency.

[0020] To realize seamless switching between the flywheel energy storage and the battery energy storage and guarantee the stability of the grid frequency, in the embodiment of the application, the real-time SOC value of the flywheel energy storage device is monitored in real time and the remaining available time thereof is estimated, so that the battery energy storage device is started in time to participate in frequency modulation before the flywheel energy storage device is about to run out of energy (or before the flywheel energy storage device is about to be fully charged), thereby avoiding the interruption of frequency modulation. Moreover, after the battery energy storage device is started, the real-time flywheel frequency modulation power of the flywheel energy storage device is correspondingly reduced, so that the total frequency modulation power remains stable during the switching process, thereby avoiding the secondary impact on the grid caused by the sudden change of the frequency modulation power and realizing seamless switching from the flywheel energy storage device to the battery energy storage device.

[0021] Figure 1 The application scenario of the frequency modulation switching method of the hybrid energy storage provided by the embodiment of the application is shown in the figure. The devices involved in the application scenario mainly include a hybrid energy storage system and a grid.

[0022] When the hybrid energy storage system participates in grid frequency modulation, the flywheel energy storage device and the battery energy storage device are provided in the hybrid energy storage system. When the grid frequency fluctuates and the hybrid energy storage system needs to support grid frequency modulation, the flywheel energy storage device can be called first to participate in grid frequency modulation due to the characteristics of the flywheel energy storage device, such as rapid response, frequent charging and discharging and almost no influence of cycle times. However, the energy storage capacity of the flywheel energy storage device is relatively limited, which is difficult to support the complete frequency modulation process alone. The embodiment of the application starts the battery energy storage device in time to participate in grid frequency modulation before the flywheel energy storage device is about to run out of energy (or before the flywheel energy storage device is about to be fully charged), thereby realizing seamless switching from the flywheel energy storage device to the battery energy storage device.

[0023] Figure 2 The structure diagram of the hybrid energy storage system provided by the embodiment of the application is shown in the figure. Figure 2 As shown in the figure, the hybrid energy storage system includes a flywheel energy storage device 201, a battery energy storage device 202 and a switching device 203.

[0024] When the flywheel energy storage device 201 alone performs grid frequency modulation, the switching device 203 acquires the real-time SOC value of the flywheel energy storage device 201 and determines the remaining available time of the flywheel energy storage device 201 based on the real-time SOC value. When the remaining available time reaches a set time threshold, the battery energy storage device 202 is controlled to start participating in grid frequency modulation. Moreover, the real-time flywheel frequency modulation power of the flywheel energy storage device 201 is correspondingly reduced based on the real-time battery frequency modulation power of the battery energy storage device 202, until the real-time battery frequency modulation power of the battery energy storage device 202 reaches the frequency modulation power required by the current grid, thereby realizing seamless switching between the flywheel energy storage device 201 and the battery energy storage device 202.

[0025] The hybrid energy storage system of Figure 2 will be described below with reference to the figure. Figure 3This invention describes a frequency regulation switching method for hybrid energy storage provided by an embodiment of the present invention. It should be noted that the embodiments of the present invention can be applied to switching equipment, meaning the frequency regulation switching method for hybrid energy storage provided by the embodiments of the present invention can be executed on the switching equipment.

[0026] See Figure 3 The flowchart illustrating the implementation of the frequency modulation switching method for hybrid energy storage provided in this embodiment of the invention is described in detail below: Step 301: During the process of the flywheel energy storage device performing grid frequency regulation, obtain the real-time SOC value of the flywheel energy storage device.

[0027] Flywheel energy storage devices primarily support grid frequency regulation through charging and discharging. When the grid frequency is higher than the rated frequency (e.g., 50Hz), the flywheel energy storage device continuously charges to lower the grid frequency to the rated frequency. When the current grid frequency is lower than the rated frequency, the flywheel energy storage device continuously discharges to raise the grid frequency to the rated frequency. Considering the relatively limited energy storage capacity of flywheel energy storage devices, during the process of supporting grid frequency regulation, its State of Charge (SOC) value will rapidly decrease to the lower limit or increase to the upper limit, making it difficult to support the entire frequency regulation process independently. Therefore, in this embodiment of the invention, during the process of the flywheel energy storage device independently supporting grid frequency regulation, its real-time SOC value can be obtained to predict the remaining usable time, thus preparing for the subsequent switch to battery energy storage devices.

[0028] Step 302: Determine the remaining available time of the flywheel energy storage device based on the real-time SOC value.

[0029] The State of Charge (SOC) value of a flywheel energy storage device reflects the energy available for grid frequency regulation within the device. In this embodiment of the invention, the remaining usable time of the flywheel energy storage device can be determined based on the aforementioned energy available for grid frequency regulation.

[0030] In some embodiments, when determining the remaining usable time of a flywheel energy storage device, the upper limit of its State of Charge (SOC), the lower limit of its SOC, and its energy capacity can be obtained first. When the flywheel energy storage device is in a discharging state, the remaining usable energy of the flywheel energy storage device is determined based on the difference between the real-time SOC value and the lower limit of its SOC, as well as its energy capacity. When the flywheel energy storage device is in a charging state, the remaining usable energy of the flywheel energy storage device is determined based on the difference between the upper limit of its SOC and the real-time SOC value, as well as its energy capacity. Finally, the remaining usable time of the flywheel energy storage device is determined based on the remaining usable energy.

[0031] When the flywheel energy storage device is in a discharging state, the remaining energy in the flywheel energy storage device is the energy available for grid frequency regulation. In this embodiment of the invention, the product of the difference between the real-time SOC value and the lower limit of SOC value and the energy capacity can be determined as the energy available for grid frequency regulation in the flywheel energy storage device, i.e., the remaining usable energy.

[0032] When the flywheel energy storage device is charging, the energy that is not fully charged in the flywheel energy storage device is the energy available for grid frequency regulation. In this embodiment of the invention, the difference between the upper limit of SOC and the real-time SOC value, multiplied by the energy capacity, can be used to determine the energy available for grid frequency regulation in the flywheel energy storage device, i.e., the remaining usable energy.

[0033] Here, the upper and lower limits of SOC can be determined based on actual conditions. For example, the upper limit of SOC can be 90%, and the lower limit of SOC can be 10%. Energy capacity is the rated energy that the flywheel energy storage device can hold, which can be determined based on the equipment parameters of the flywheel energy storage device.

[0034] In some embodiments, the real-time flywheel frequency modulation power of the flywheel energy storage device can be obtained; then, based on the ratio of the remaining available energy to the real-time flywheel frequency modulation power, the remaining available time of the flywheel energy storage device can be determined.

[0035] The embodiments of the present invention can collect the real-time flywheel frequency modulation power of the flywheel energy storage device in real time, and determine the remaining available time of the flywheel energy storage device by the ratio of the remaining available energy to the real-time flywheel frequency modulation power.

[0036] Step 303: When the remaining available time reaches the set time threshold, control the battery energy storage device to start participating in grid frequency regulation.

[0037] Here, the time threshold can be determined based on the startup time of the battery storage device. For example, the time threshold can be set to be equivalent to the startup time of the battery storage device.

[0038] When the remaining available time reaches the start-up time of the battery energy storage device, the battery energy storage device is controlled to start up, so as to ensure that the battery energy storage device can be fully started before the remaining available energy of the flywheel energy storage device is exhausted, thus avoiding the occurrence of frequency regulation interruption.

[0039] Step 304: Based on the real-time battery frequency regulation power of the battery energy storage device, reduce the real-time flywheel frequency regulation power of the flywheel energy storage device until the real-time battery frequency regulation power of the battery energy storage device reaches the frequency regulation power required by the current power grid.

[0040] After the battery energy storage device is started, the real-time battery frequency regulation power of the battery energy storage device can be collected in real time, and the real-time flywheel frequency regulation power of the flywheel energy storage device can be reduced accordingly. This ensures that the sum of the real-time battery frequency regulation power and the real-time flywheel frequency regulation power is always equal to the frequency regulation power required by the power grid, so as to avoid frequency regulation fluctuations and affect the stability of the power grid frequency.

[0041] In this embodiment, by monitoring the real-time SOC value of the flywheel energy storage device and estimating its remaining usable time, the battery energy storage device can be activated in time to participate in frequency regulation before the flywheel energy is about to be depleted (or before the flywheel energy is about to be fully charged). This process ensures a smooth continuity of the power source for grid frequency regulation, effectively avoiding power interruption caused by insufficient support capacity of the flywheel alone, thereby ensuring the stability of the grid frequency. Furthermore, after the battery energy storage device is activated, the real-time flywheel frequency regulation power of the flywheel energy storage device is reduced accordingly based on its output real-time battery frequency regulation power, realizing coordinated output between the two energy storage devices. This control method keeps the total frequency regulation power stable during the switching process, avoiding secondary impacts on the grid caused by sudden changes in frequency regulation power, and achieving seamless switching from the flywheel energy storage device to the battery energy storage device.

[0042] The following section details the switching process between flywheel energy storage devices and battery energy storage devices.

[0043] During the process of the flywheel energy storage device supporting grid frequency regulation alone, its remaining available time is continuously shortened. When the remaining available time is shortened to the set time threshold, the battery energy storage device can be controlled to start and begin to support grid frequency regulation together with the flywheel energy storage device.

[0044] In some embodiments, a set time threshold can be determined based on the frequency regulation power required by the current power grid; when the remaining available time reaches the set time threshold, the battery energy storage device is controlled to start based on the frequency regulation power required by the current power grid.

[0045] Here, a mathematical mapping relationship between the grid frequency and the frequency regulation power can be predetermined. This mathematical mapping relationship is used to reflect the frequency regulation power required by the grid at any given grid frequency. This mathematical mapping relationship can be reflected by a frequency-power characteristic (FPC) curve.

[0046] The method for determining the mathematical mapping relationship (i.e., the FPC curve) between the above-mentioned power grid frequency and frequency regulation power is as follows: First, the frequency reference deviation can be obtained from the relevant technical specifications, and the ratio of the rated power of the hybrid energy storage system to the frequency reference deviation can be calculated. This ratio can then be determined as the frequency modulation slope.

[0047] Here, for a hybrid energy storage system consisting of flywheel energy storage and battery energy storage, the rated power of the hybrid energy storage system can be the sum of the rated power of the flywheel energy storage and the rated power of the battery energy storage.

[0048] Frequency reference deviation refers to the frequency deviation that produces 100% of the rated power of the energy storage system. For example, the frequency reference deviation can be 0.2Hz, meaning that the hybrid energy storage system can only produce 100% power output when the grid frequency fluctuates by 0.2Hz above or below the rated frequency (e.g., 50Hz).

[0049] The frequency regulation slope refers to the frequency regulation power that the hybrid energy storage system needs to provide for every 1 Hz change in the grid frequency. For example, if the rated power of the hybrid energy storage system is 5 MW and the frequency reference deviation is 0.2 Hz, then the frequency regulation slope can be 5 MW / 0.2 Hz = 25 MW / Hz. That is, for every 0.1 Hz change in the grid frequency, the hybrid energy storage system needs to provide 2.5 MW of power output.

[0050] Next, the frequency modulation dead zone can be obtained from the relevant technical specifications, for example, 50±0.03Hz, which means that when the grid frequency is in the range of 50±0.03Hz, the required frequency modulation power is 0.

[0051] Finally, when the grid frequency exceeds the frequency regulation dead zone, the product of the change in grid frequency (i.e., the difference between the rated frequency of 50Hz and the grid frequency) and the above-mentioned frequency regulation slope can be calculated, and this product can be determined as the frequency regulation power required by the grid, thereby obtaining the mathematical mapping relationship between grid frequency and frequency regulation power.

[0052] Using a grid rated frequency of 50Hz as a reference, when the grid frequency is within the frequency regulation dead zone (e.g., 50 ± 0.03Hz), the required frequency regulation power is 0 to avoid unnecessary frequent responses. When the grid frequency is higher than the upper limit of the frequency regulation dead zone (e.g., 50.03Hz), the hybrid energy storage system needs to perform charging operations to reduce the grid frequency, and the higher the grid frequency, the higher the required charging power (i.e., frequency regulation power). When the grid frequency is lower than the lower limit of the frequency regulation dead zone (e.g., 49.97Hz), the hybrid energy storage system needs to perform discharging operations to increase the grid frequency, and the lower the grid frequency, the higher the required discharging power (i.e., frequency regulation power).

[0053] In this embodiment of the invention, when the frequency modulation power is positive, it is used to characterize the discharge power; the larger the absolute value of the frequency modulation power, the greater the discharge power. When the frequency modulation power is negative, it is used to characterize the charging power; the larger the absolute value of the frequency modulation power, the greater the charging power.

[0054] The embodiments of the present invention can obtain the current power grid frequency in real time, and based on the power grid frequency and the above-mentioned mathematical mapping relationship, obtain the frequency regulation power required by the current power grid in real time.

[0055] Based on this, in determining the set time threshold, embodiments of the present invention can obtain a preset lookup table. This lookup table contains the startup time required for the battery energy storage device to stably output different frequency regulation powers from receiving a startup command. Then, based on the lookup table and the frequency regulation power required by the current power grid, the startup time of the battery energy storage device is determined; subsequently, based on the startup time and a preset safety margin time, the set time threshold is determined.

[0056] Here, embodiments of the present invention can employ experimental calibration to determine the startup time required for the battery energy storage device to stably output different frequency modulation powers from receiving a startup command. A lookup table is then established based on this startup time and the corresponding frequency modulation power.

[0057] Specifically, for each frequency modulation power, a start command can be sent to the battery energy storage device based on the frequency modulation power to control the battery energy storage device to stably output the frequency modulation power. At the same time, a timer is started to record the duration from when the start command is issued to when the battery energy storage device stably outputs the frequency modulation power. This duration is the start time corresponding to the frequency modulation power.

[0058] Here, for each frequency modulation power, the test can be repeated multiple times to cover different operating conditions of the battery energy storage device, resulting in multiple durations. The maximum value among these durations is then determined as the final start-up time. It should be noted that the SOC value and ambient temperature of the battery energy storage device differ under different operating conditions.

[0059] The embodiments of the present invention can determine the required frequency regulation power of the current power grid based on the above-mentioned mathematical mapping relationship, or it can determine the required frequency regulation power of the current power grid based on the real-time flywheel frequency regulation power of the flywheel energy storage device. Then, the start-up time of the battery energy storage device is determined by looking up a table based on the required frequency regulation power of the current power grid. It can be understood that during the process where the flywheel energy storage device independently supports power grid frequency regulation, the real-time flywheel frequency regulation power of the flywheel energy storage device is the required frequency regulation power of the current power grid.

[0060] In addition, to address communication delays and uncertain buffer times, this embodiment of the invention adds a safety margin time to the above-mentioned startup time to determine the final set time threshold, thereby ensuring that the battery energy storage device can start up within the set time threshold and stably output the frequency regulation power required by the power grid.

[0061] In this embodiment of the invention, when the remaining available time is shortened to a set time threshold, the frequency regulation power required by the current power grid can be used as the target frequency regulation power, and the battery energy storage device can be started according to the target frequency regulation power, so that the real-time battery frequency regulation power of the battery energy storage device can gradually climb to the target frequency regulation power and stably output the target frequency regulation power.

[0062] As the real-time battery frequency regulation power gradually increases, in order to avoid frequency regulation fluctuations and affect the stability of the power grid frequency, the embodiments of the present invention can correspondingly reduce the real-time flywheel frequency regulation power of the flywheel energy storage device, so as to ensure that the battery energy storage device and the flywheel energy storage device can jointly meet the frequency regulation power required by the power grid.

[0063] In some embodiments, during the startup process of the battery energy storage device, the real-time battery frequency regulation power of the battery energy storage device can be obtained; and based on the difference between the frequency regulation power required by the current power grid and the real-time battery frequency regulation power, the frequency regulation power that the flywheel energy storage device needs to provide at present can be determined; then, the real-time flywheel frequency regulation power of the flywheel energy storage device is reduced according to the frequency regulation power that the flywheel energy storage device needs to provide at present.

[0064] It is understandable that when both the flywheel energy storage device and the battery energy storage device participate in grid frequency regulation, the sum of the real-time battery frequency regulation power and the real-time flywheel frequency regulation power is the frequency regulation power required by the current grid. Based on this, this embodiment of the invention acquires the real-time battery frequency regulation power during the startup process of the battery energy storage device, and determines the required frequency regulation power from the flywheel energy storage device by calculating the difference between the current grid-required frequency regulation power and the real-time battery frequency regulation power. Here, the real-time flywheel frequency regulation power can be reduced to the required frequency regulation power from the flywheel energy storage device to avoid frequency regulation fluctuations.

[0065] It is important to note that as frequency regulation continues, the required frequency regulation power of the power grid gradually decreases, meaning the target frequency regulation power corresponding to the battery energy storage device gradually decreases. Therefore, this embodiment of the invention can collect the required frequency regulation power of the power grid in real time during the startup and subsequent operation of the battery energy storage device, and dynamically adjust the target frequency regulation power corresponding to the battery energy storage device in real time according to the required power grid, thereby adjusting the operating state of the battery energy storage device in real time.

[0066] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0067] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0068] Figure 4 A schematic diagram of the hybrid energy storage frequency modulation switching device provided in an embodiment of the present invention is shown. For ease of explanation, only the parts related to the embodiment of the present invention are shown, and are described in detail below: like Figure 4As shown, the hybrid energy storage frequency switching device 4 includes: an acquisition module 41, a calculation module 42, and a switching module 43.

[0069] The acquisition module 41 is used to acquire the real-time SOC value of the flywheel energy storage device during the process of grid frequency regulation of the flywheel energy storage device; Calculation module 42 is used to determine the remaining available time of the flywheel energy storage device based on the real-time SOC value; Switching module 43 is used for: When the remaining available time reaches the set time threshold, the control battery energy storage device begins to participate in grid frequency regulation; Based on the real-time battery frequency regulation power of the battery energy storage device, the real-time flywheel frequency regulation power of the flywheel energy storage device is reduced accordingly until the real-time battery frequency regulation power of the battery energy storage device reaches the frequency regulation power required by the current power grid.

[0070] Optionally, switch module 43 is used specifically for: Determine the set time threshold based on the frequency regulation power required by the current power grid; When the remaining available time reaches the set time threshold, the battery energy storage device is controlled to start based on the frequency regulation power required by the current power grid.

[0071] Optionally, switch module 43 is used specifically for: Obtain a preset lookup table; the lookup table contains the startup time required for the battery energy storage device to stably output different frequency modulation power from receiving the startup command. The start-up time of the battery energy storage device is determined based on the lookup table and the frequency regulation power required by the current power grid. The set time threshold is determined based on the startup time and the preset safety margin time.

[0072] Optionally, switch module 43 is used specifically for: During the startup process of the battery energy storage device, the real-time battery frequency modulation power of the battery energy storage device is obtained; Based on the difference between the frequency regulation power required by the current power grid and the real-time frequency regulation power of the battery, the frequency regulation power that the flywheel energy storage device needs to provide at present is determined. Reduce the real-time flywheel frequency regulation power of the flywheel energy storage device according to the current required frequency regulation power.

[0073] Optional, calculation module 42, specifically used for: Obtain the upper limit of SOC, lower limit of SOC, and energy capacity of the flywheel energy storage device; When the flywheel energy storage device is in a discharge state, the remaining usable energy of the flywheel energy storage device is determined based on the difference between the real-time SOC value and the lower limit of SOC value, as well as the energy capacity. When the flywheel energy storage device is in a charging state, the remaining available energy of the flywheel energy storage device is determined based on the difference between the upper limit of SOC and the real-time SOC value, as well as the energy capacity. Based on the remaining available energy, determine the remaining available time of the flywheel energy storage device.

[0074] Optional, calculation module 42, specifically used for: Obtain the real-time flywheel frequency modulation power of the flywheel energy storage device; The remaining usable time of the flywheel energy storage device is determined based on the ratio of the remaining available energy to the real-time flywheel frequency modulation power.

[0075] This device embodiment can be used to implement the above method embodiment, and its technical principle and implementation effect are the same as those of the above method embodiment, so they will not be repeated here.

[0076] Figure 5 This is a schematic diagram of a switching device provided in an embodiment of the present invention. Figure 5 As shown, the switching device in this embodiment includes a processor 50 and a memory 51. The memory 51 stores a computer program 52. When the processor 50 executes the computer program 52, it implements the steps in the various method embodiments described above. Alternatively, when the processor 50 executes the computer program 52, it implements the functions of each module / unit in the various device embodiments described above.

[0077] For example, computer program 52 may be divided into one or more modules / units, which are stored in memory 51 and executed by processor 50 to perform the present invention. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of computer program 52 in a switching device.

[0078] The switching device may include, but is not limited to, processor 50 and memory 51. Those skilled in the art will understand that... Figure 5 This is merely an example of switching device 5 and does not constitute a limitation on the switching device. It may include more or fewer components than shown, or combine certain components, or different components. For example, the switching device may also include input / output devices, network access devices, buses, etc.

[0079] The processor 50 can be a central processing unit (CPU), or 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 any conventional processor.

[0080] The memory 51 can be an internal storage unit of the switching device, such as the hard drive or RAM of the switching device. The memory 51 can also be an external storage device of the switching device, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the switching device. Furthermore, the memory 51 can include both internal and external storage units of the switching device. The memory 51 is used to store the computer program 52 and other programs and data required by the switching device. The memory 51 can also be used to temporarily store data that has been output or will be output.

[0081] For the sake of simplicity and clarity, only the above-described functional modules / units are used as examples. In practical applications, the functions described above can be assigned to different functional modules / units as needed. These modules / units can be implemented in hardware, software, or a combination of both.

[0082] This invention also provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the methods described in the above-described method embodiments.

[0083] This invention also provides a computer program product, including a computer program. When the computer program is executed by a processor, it implements the methods described in the above-described method embodiments.

[0084] Computer programs include computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. Computer-readable media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0085] In the above embodiments, the descriptions of each embodiment have their own emphasis. Parts not detailed or described in a particular embodiment can be referred to in the relevant descriptions of other embodiments. Unless otherwise specified or in conflict with logic, the terminology and / or descriptions between different embodiments are consistent and can be referenced interchangeably. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0086] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A frequency regulation switching method for hybrid energy storage, characterized in that, include: During the process of grid frequency regulation by the flywheel energy storage device, the real-time SOC value of the flywheel energy storage device is obtained; Based on the real-time SOC value, the remaining available time of the flywheel energy storage device is determined; When the remaining available time reaches a set time threshold, the battery energy storage device is controlled to start participating in grid frequency regulation; Based on the real-time battery frequency regulation power of the battery energy storage device, the real-time flywheel frequency regulation power of the flywheel energy storage device is reduced accordingly until the real-time battery frequency regulation power of the battery energy storage device reaches the frequency regulation power required by the current power grid.

2. The frequency regulation switching method for hybrid energy storage according to claim 1, characterized in that, When the remaining available time reaches a set time threshold, controlling the battery storage device to start participating in grid frequency regulation includes: The set time threshold is determined based on the frequency regulation power required by the current power grid; When the remaining available time reaches the set time threshold, the battery energy storage device is controlled to start based on the frequency regulation power required by the current power grid.

3. The frequency regulation switching method for hybrid energy storage according to claim 2, characterized in that, Determining the set time threshold based on the frequency regulation power required by the current power grid includes: Obtain a preset lookup table; the lookup table contains the startup time required for the battery energy storage device to stably output different frequency modulation power from receiving the startup command. Based on the lookup table and the frequency regulation power required by the current power grid, the start-up time of the battery energy storage device is determined; The set time threshold is determined based on the startup time and the preset safety margin time.

4. The frequency regulation switching method for hybrid energy storage according to any one of claims 1-3, characterized in that, The reduction of the real-time flywheel frequency regulation power of the flywheel energy storage device based on the real-time battery frequency regulation power of the battery energy storage device includes: During the startup process of the battery energy storage device, the real-time battery frequency regulation power of the battery energy storage device is acquired; Based on the difference between the frequency regulation power required by the current power grid and the real-time battery frequency regulation power, the frequency regulation power currently required to be provided by the flywheel energy storage device is determined. Reduce the real-time flywheel frequency regulation power of the flywheel energy storage device according to the frequency regulation power provided by the flywheel energy storage device as needed.

5. The frequency regulation switching method for hybrid energy storage according to any one of claims 1-3, characterized in that, Determining the remaining available time of the flywheel energy storage device based on the real-time SOC value includes: Obtain the upper limit of SOC, the lower limit of SOC, and the energy capacity of the flywheel energy storage device; When the flywheel energy storage device is in a discharge state, the remaining usable energy of the flywheel energy storage device is determined based on the difference between the real-time SOC value and the lower limit of SOC value, as well as the energy capacity. When the flywheel energy storage device is in a charging state, the remaining available energy of the flywheel energy storage device is determined based on the difference between the upper limit of SOC and the real-time SOC value, as well as the energy capacity. Based on the remaining available energy, the remaining available time of the flywheel energy storage device is determined.

6. The frequency regulation switching method for hybrid energy storage according to claim 5, characterized in that, Determining the remaining usable time of the flywheel energy storage device based on the remaining available energy includes: Obtain the real-time flywheel frequency modulation power of the flywheel energy storage device; The remaining usable time of the flywheel energy storage device is determined based on the ratio of the remaining available energy to the real-time flywheel frequency modulation power.

7. A frequency modulation switching device for hybrid energy storage, characterized in that, include: The acquisition module is used to acquire the real-time SOC value of the flywheel energy storage device during the process of grid frequency regulation. A calculation module is used to determine the remaining available time of the flywheel energy storage device based on the real-time SOC value; Switching modules, used for: When the remaining available time reaches a set time threshold, the battery energy storage device is controlled to start participating in grid frequency regulation; Based on the real-time battery frequency regulation power of the battery energy storage device, the real-time flywheel frequency regulation power of the flywheel energy storage device is reduced accordingly until the real-time battery frequency regulation power of the battery energy storage device reaches the frequency regulation power required by the current power grid.

8. A switching device, characterized in that, It includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the method as described in any one of claims 1 to 6.

9. A hybrid energy storage system, characterized in that, It includes a flywheel energy storage device, a battery energy storage device, and a switching device as described in claim 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method as described in any one of claims 1 to 6.

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