Frequency Control Method for Offshore Wind Power Hydrogen Energy System

Abstract

The present application relates to a frequency control method for an offshore wind power hydrogen energy system. First, obtain the power supply frequencies of the power supply side of the power supply system at each moment from the current moment to the initial moment, and determine the power adjustment amounts of each power device according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs. Then, adjust the output powers of each power device according to the power adjustment amounts of each power device to control the power supply frequency on the grid side within a preset frequency range. This method uses the power distribution strategies of each adjustment stage to adjust the powers of each power device respectively, which can make the power supply on the grid side within a preset range and ensure the stability of the power supply system.

Description

Technical Field

[0001] The present application relates to the field of power systems, and particularly to a frequency control method for an offshore wind power hydrogen energy system. Background Art

[0002] The offshore wind power - hydrogen energy system is an integrated energy system centered around an offshore wind farm, which uses hydrogen production, storage, and hydrogen power generation equipment as flexible adjustment units. It can provide energy for offshore electrical and hydrogen loads nearby, and supply electrical and hydrogen energy as well as auxiliary services such as primary and secondary frequency modulation to the shore through a flexible DC transmission system and a hydrogen transmission system.

[0003] In the offshore wind power - hydrogen energy system, when the power supply frequency on the grid side changes, it will affect the normal use of electrical equipment, and at the same time, it will also endanger the normal operation of power supply equipment. Based on this, when the power supply frequency on the grid side changes, it is necessary to adjust the power supply frequency on the grid side through power equipment to ensure the stability of the power supply frequency. Usually, when adjusting the power supply frequency on the grid side, only wind turbines are used to adjust the power supply frequency on the grid side.

[0004] However, in the prior art, when using wind turbines to adjust the power supply frequency on the grid side, the change and fluctuation of the power supply frequency on the grid side are relatively large, and the ability of wind turbines to adjust the frequency is not high. Summary of the Invention

[0005] Based on this, in view of the above technical problems, it is necessary to provide a frequency control method for an offshore wind power hydrogen energy system that uses multiple power equipment to cooperate in adjusting the power supply frequency on the grid side. This method can make the change and fluctuation of the power supply frequency on the grid side smaller when multiple power equipment adjust the power supply frequency on the grid side.

[0006] In a first aspect, the present application provides a frequency control method, which includes:

[0007] Obtain the power supply frequencies of each moment from the current moment to the initial moment on the power supply side of the power supply system; the power supply side includes multiple power equipment; the initial moment represents the moment when the power supply frequency on the grid side of the power supply system starts to change;

[0008] Determine the power adjustment amount of each power equipment according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs; among them, the power distribution strategy corresponding to each adjustment stage is different;

[0009] Adjust the output power of each power equipment according to the power adjustment amount of each power equipment to control the power supply frequency on the grid side within a preset frequency range.

[0010] In one embodiment, before obtaining the power supply frequencies of the power supply side of the power supply system at each moment between the current moment and the initial moment, the method further includes:

[0011] Determine the time ranges of each adjustment stage according to the initial moment and the stage durations of a plurality of preset adjustment stages; the plurality of adjustment stages include a frequency modulation stage, a power compensation stage, and a voltage recovery stage;

[0012] Determine the adjustment stage to which the current moment belongs according to the current moment and the time ranges of each adjustment stage.

[0013] In one embodiment, if the adjustment stage to which the current moment belongs is the frequency modulation stage, obtaining the power supply frequencies of the power supply side of the power supply system at each moment between the current moment and the initial moment includes:

[0014] Obtain the first power supply frequency change amounts at each moment between the current moment and the initial moment on the grid side of the power supply system and the voltage-frequency droop coefficient of the converter station on the grid side;

[0015] Determine the change amount of the DC bus voltage of the power supply system according to each first power supply frequency change amount and the voltage-frequency droop coefficient;

[0016] Determine the second power supply frequency change amounts at each moment between the current moment and the initial moment on the power supply side according to the change amount of the DC bus voltage and the frequency-voltage droop coefficient of the converter station on the power supply side;

[0017] Determine the power supply frequencies at each moment between the current moment and the initial moment on the power supply side according to each second power supply frequency change amount and the initial power supply frequency at the initial moment on the power supply side.

[0018] In one embodiment, determining the power adjustment amounts of each power device according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs includes:

[0019] Calculate the frequency change rate between the current moment and the initial moment according to each power supply frequency;

[0020] Based on the droop control strategy, the inertia response strategy, the second power supply frequency change amount, the frequency change rate, and the inertia control coefficients corresponding to each power device, determine the power adjustment amounts of each power device; the inertia control coefficients include the droop coefficient and the inertia response coefficient.

[0021] In one embodiment, if the adjustment stage to which the current moment belongs is the power compensation stage or the voltage recovery stage, obtaining the power supply frequencies of the power supply side of the power supply system at each moment between the current moment and the initial moment includes:

[0022] Send a power supply frequency acquisition instruction to the frequency detection device, where the frequency detection device is a device in the power supply system used to collect the power supply frequencies at each moment from the current moment to the initial moment on the power supply side;

[0023] Receive the power supply frequencies at each moment from the current moment to the initial moment on the power supply side sent by the frequency detection device.

[0024] In one embodiment, if the adjustment stage to which the current moment belongs is the power compensation stage, then determine the power adjustment amount of each power device according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs, including:

[0025] Obtain the minimum frequency in the frequency modulation stage from each power supply frequency;

[0026] Determine the fixed power compensation time in the power compensation stage according to the minimum frequency and the preset time-frequency coefficient;

[0027] Determine the total power value that each power device needs to adjust according to the fixed power compensation time;

[0028] Determine the power adjustment amount of each power device according to the total power value.

[0029] In one embodiment, the multiple devices include a wind turbine generator set, an electrolytic cell, and a fuel cell; determine the total power value that the multiple power devices need to adjust according to the fixed power compensation time, including:

[0030] If the current moment is greater than or equal to the first preset moment and less than or equal to the second preset moment, then determine the preset fixed compensation power as the total power value that the multiple power devices need to adjust; the first preset moment is the starting moment of the power compensation stage, and the difference between the second preset moment and the first preset moment is the fixed power compensation time;

[0031] If the current moment is greater than the second preset moment and less than or equal to the third preset moment, determine the total power values that the wind turbine generator set, the electrolytic cell, and the fuel cell need to adjust through the functional relationship among the current moment, the second preset moment, the third preset moment, the fixed compensation power, and the total power value; the third preset moment is the ending moment of the power compensation stage; the second preset moment is less than the third preset moment; the functional relationship is constructed according to the characteristics of the wind turbine generator set in the power compensation stage.

[0032] In one embodiment, determine the power adjustment amount of each power device according to the total power value, including:

[0033] Obtain the remaining capacity of the electrolytic cell and the remaining capacity of the fuel cell;

[0034] If the sum of the remaining capacity of the electrolyzer and the remaining capacity of the fuel cell is greater than or equal to the fixed compensation power, then, based on the remaining capacity of the electrolyzer, the remaining capacity of the fuel cell, and the total power value, determine the power adjustment amounts of the electrolyzer and the fuel cell, and determine that the power adjustment amount of the wind turbine is 0;

[0035] If the sum of the remaining capacity of the electrolyzer and the remaining capacity of the fuel cell is less than the fixed compensation power, then, based on the remaining capacity of the electrolyzer, the fixed compensation power, and the total power value, determine the power adjustment amount of the electrolyzer; based on the remaining capacity of the fuel cell, the fixed compensation power, and the total power value, determine the power adjustment amount of the fuel cell; and based on the total power value, the power adjustment amount of the electrolyzer, and the power adjustment amount of the fuel cell, determine the power adjustment amount of the wind turbine.

[0036] In one embodiment, if the adjustment stage to which the current moment belongs is the voltage recovery stage; then, according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs, determine the power adjustment amounts of each power equipment, including:

[0037] Obtain the power supply frequency at the third preset moment, and calculate the third power supply frequency change amount of the power supply side from the third preset moment to the initial moment according to the power supply frequency at the third preset moment; the third preset moment is the end moment of the power compensation stage;

[0038] According to the third power supply frequency change amount and the frequency-voltage droop coefficient, determine the voltage offset amount of the DC bus from the third preset moment to the initial moment;

[0039] According to the slope of the DC bus voltage recovery and the voltage offset amount, determine the total power value that each power equipment needs to adjust;

[0040] Determine the adjustment amounts of each power equipment according to the total power value.

[0041] In one embodiment, according to the slope of the DC bus voltage recovery and the voltage offset amount, determining the total power value that each power equipment needs to adjust includes:

[0042] According to the slope of the DC bus voltage recovery and the voltage offset amount, determine the duration of the voltage recovery of the power supply side;

[0043] According to the rated capacitance of the DC bus, the slope, and the voltage of the DC bus at the third preset moment, determine the total power value that each power equipment needs to adjust during the voltage recovery process in the power supply system;

[0044] According to the total power value and the duration of the voltage recovery, determine the total power value that each power equipment needs to adjust.

[0045] In a second aspect, the present application further provides a frequency control device, and the device includes:

[0046] An acquisition module, configured to acquire the power supply frequencies of the power supply side of the power supply system at each moment from the current moment to the initial moment; the power supply side includes a plurality of power devices; the initial moment represents the moment when the power supply frequency of the grid side of the power supply system starts to change;

[0047] A distribution module, configured to determine the power adjustment amount of each power device according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs; wherein, the power distribution strategies corresponding to each adjustment stage are different;

[0048] An adjustment module, configured to adjust the output power of each power device according to the power adjustment amount of each power device to control the power supply frequency of the grid side within a preset frequency range.

[0049] In a third aspect, an embodiment of the present application provides a computer device, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the steps of any method provided in the embodiment of the first aspect are implemented.

[0050] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of any method provided in the embodiment of the first aspect are implemented.

[0051] In a fifth aspect, an embodiment of the present application provides a computer program product, including a computer program. When the computer program is executed by a processor, the steps of any method provided in the embodiment of the first aspect are implemented.

[0052] A frequency control method for an offshore wind power hydrogen energy system provided by an embodiment of the present application first acquires the power supply frequencies of the power supply side of the power supply system at each moment from the current moment to the initial moment, and determines the power adjustment amount of each power device according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs. Then, according to the power adjustment amount of each power device, the output power of each power device is adjusted to control the power supply frequency of the grid side within a preset frequency range. In this method, when the frequency of the grid side of the power supply system changes, the power supply side will acquire the power supply frequencies at each moment after the moment when the grid side starts to change, and then according to the power supply frequencies at each moment and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs, the power distribution strategies corresponding to different adjustment stages are different, which ensures that when the power supply frequency of the grid side is adjusted, the change of the power supply frequency fluctuates less, improving the stability of the power supply; and, by using a plurality of power devices to jointly participate in power adjustment and using the power distribution strategies of each adjustment stage to adjust the power of each power device respectively, the power supply power of the grid side can be kept within a preset range, ensuring the stability of the power supply system. Description of the Drawings

[0053] Figure 1 It is an application environment diagram of the frequency control method in an embodiment;

[0054] Figure 2 It is a schematic flowchart of the frequency control method in an embodiment;

[0055] Figure 3 It is a system structure diagram of the frequency control method in an embodiment;

[0056] Figure 4 It is a schematic flowchart of the frequency control method in another embodiment;

[0057] Figure 5 It is a schematic flowchart of the frequency control method in another embodiment;

[0058] Figure 6 It is a system structure diagram of the frequency control method in another embodiment;

[0059] Figure 7 It is a schematic flowchart of the frequency control method in another embodiment;

[0060] Figure 8 It is a strategy block diagram of the frequency control method in an embodiment;

[0061] Figure 9 It is a schematic flowchart of the frequency control method in another embodiment;

[0062] Figure 10 It is a schematic flowchart of the frequency control method in another embodiment;

[0063] Figure 11 It is a schematic flowchart of the frequency control method in another embodiment;

[0064] Figure 12 It is a schematic flowchart of the frequency control method in another embodiment;

[0065] Figure 13 It is a schematic diagram of the power change of a wind turbine in an embodiment;

[0066] Figure 14 It is a system structure diagram of the frequency control method in another embodiment;

[0067] Figure 15 It is a schematic diagram of the frequency change of different frequency modulation strategies in an embodiment;

[0068] Figure 16 It is a schematic diagram of the power change of different frequency modulation strategies in an embodiment;

[0069] Figure 17Schematic flowchart of a frequency control method in another embodiment;

[0070] Figure 18 Block diagram of a frequency control device in one embodiment;

[0071] Figure 19 Internal structure diagram of a computer device in one embodiment. Detailed implementation manners

[0072] In order to make the objectives, technical solutions and advantages of the present application more clear and understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0073] The frequency control method provided by the embodiments of the present application can be in the application environment as Figure 1 shown. Among them, the power supply system communicates with the server through a network. The database can store the data that the server needs to process. The database can be integrated on the server, or placed in the cloud or other network servers.

[0074] Among them, the server can be implemented by an independent server or a server cluster composed of multiple servers; the power supply system is a system that generates electric energy and supplies and transmits it to electrical equipment, consisting of a power system and a power transmission and distribution system. The power system includes a mine power supply system, a city power supply system, a power traction power supply system, an offshore wind power-hydrogen energy system, etc.

[0075] The embodiments of the present application provide a frequency control method for an offshore wind power-hydrogen energy system. The method uses multiple power equipment to jointly adjust the power supply frequency on the grid side, which can make the fluctuation smaller when the power supply frequency on the grid side is adjusted, and improve the stability of the power supply system.

[0076] The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application.

[0077] In one embodiment, a frequency control method is provided for application in Figure 1Taking the application environment in [the specific context] as an example, this embodiment involves first obtaining the power supply frequencies of the power supply side of the power supply system at each moment from the current moment to the initial moment, and determining the power adjustment amounts of each power device according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs, and adjusting the output powers of each power device according to the power adjustment amounts of each power device to control the power supply frequency on the grid side within a preset frequency range. The specific process is as follows Figure 2 As shown, this embodiment includes the following steps:

[0078] S201, obtain the power supply frequencies of the power supply side of the power supply system at each moment from the current moment to the initial moment; the power supply side includes multiple power devices; the initial moment represents the moment when the power supply frequency on the grid side of the power supply system starts to change.

[0079] A power supply system is a system that generates electrical energy, supplies and transmits it to electrical equipment, consisting of a power supply system and a power transmission and distribution system. The power supply sources can be divided into mine power supply systems, urban power supply systems, electric traction power supply systems, aircraft electrical systems, etc.; generally, the side that generates electrical energy in the power supply system is called the power supply side, and the side that provides electrical energy for electrical equipment in the power supply system is called the grid side.

[0080] In the embodiment of the present application, the power supply system can be an offshore wind power - hydrogen energy system, which directly converts the electrical energy generated by wind power into hydrogen through a water electrolysis hydrogen production device, and produces hydrogen that is convenient for long - term storage through electrolyzing water.

[0081] The power supply frequency in the power supply system is one of the important indicators of power quality and is also the core parameter on which the grid dispatching depends to control the operation of the power system. Once the power supply frequency deviates too much, it will cause the grid to collapse and lead to large - scale power outages.

[0082] When the electricity generated on the grid side is in real - time balance with the electricity consumed by the user, the power supply frequency on the grid side will be maintained at the rated frequency; if the electricity generated on the grid side is greater than the electricity used, the power supply frequency on the grid side will increase, and if the electricity generated on the grid side is less than the electricity used, the power supply frequency on the grid side will decrease; due to the randomness of load fluctuations in the power supply system, the frequency on the grid side also changes in real - time. Only when the power supply frequency on the grid side is maintained within the allowable deviation range can the power supply system operate safely and stably.

[0083] However, if the electrical load suddenly changes, the power supply frequency on the grid side will also change. If the change in the power supply frequency is not within the allowable deviation range, the power devices on the power supply side will participate in frequency modulation to keep the grid frequency within a certain range of operation.

[0084] When power equipment on the power supply side participates in frequency modulation, first obtain the moment when the power supply frequency on the power supply side starts to change, that is, the initial moment, and obtain the power supply frequency corresponding to the power supply side at the initial moment.

[0085] Then, obtain the power supply frequencies of the power supply side of the power supply system at each moment between the current moment and the initial moment, where the current moment represents any moment during the frequency adjustment process on the grid side after the power supply frequency on the grid side changes.

[0086] The way to obtain the power supply frequencies at each moment can be to first obtain multiple path waveform signals of the power supply side at each moment, and then use the frequency of the waveform signal with the smallest distortion degree among the multiple path waveform signals at each moment as the power supply frequency of the power supply side at each moment.

[0087] Among them, the power equipment includes power generation equipment and power supply equipment. In the embodiments of the present application, the power equipment can be power generation equipment, and the power generation equipment includes power station boilers, steam turbines, gas turbines, water turbines, generators, transformers, etc.

[0088] S202, determine the power adjustment amount of each power equipment according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs; among them, the power distribution strategies corresponding to each adjustment stage are different.

[0089] The frequency control stage is divided into multiple adjustment stages, where one adjustment stage corresponds to one power distribution strategy, and different adjustment stages correspond to different power distribution strategies; the power distribution strategy is a strategy for allocating power adjustment amounts to each power equipment corresponding to each adjustment stage. For example, this strategy can allocate the power adjustment amounts of multiple power equipment in a preset ratio.

[0090] According to the preset adjustment stage, it can be determined which adjustment stage the current moment is in, and according to the adjustment stage to which the current moment belongs, determine the power distribution strategy at the current moment as the target power distribution strategy. Therefore, the power adjustment amount of each power equipment can be calculated according to the power supply frequencies of the power supply side at each moment and the target power distribution strategy.

[0091] The way to determine the power adjustment amount of each power equipment can be determined through a neural network model. Specifically, each power supply frequency and the target power distribution strategy are used as the input of a preset power distribution model, and then the power distribution model is trained, and finally the power adjustment amount of each power equipment is output.

[0092] Among them, the power equipment can be wind turbine generators and diesel generator sets.

[0093] S203, adjust the output power of each power equipment according to the power adjustment amount of each power equipment to control the power supply frequency on the grid side within a preset frequency range.

[0094] Taking the power supply system of an offshore wind power - hydrogen energy system as an example, as Figure 3 shown Figure 3 is the basic structure diagram of the system. When the power supply frequency on the grid side changes, the power supply side will obtain the power supply frequency at each moment, and adjust the power of multiple power devices on the power supply side according to the power supply frequency on the power supply side, and then control the power supply frequency on the grid side to be within a preset power supply range by adjusting the output power of the multiple power devices.

[0095] Taking the power device as a wind turbine as an example, the output power of the wind turbine is adjusted according to the power adjustment amount of the wind turbine. If the power adjustment amount of the wind turbine is +5w, it means that the power of the wind turbine needs to be increased by 5w. The output power of the wind turbine can be increased by increasing the wind speed of the wind turbine, and the adjusted output power is transmitted to the grid side. The grid side controls the power supply frequency on the grid side through the adjusted output power.

[0096] Optionally, the preset frequency range can be 50 ± 0.1 Hz.

[0097] In the above frequency control method, first, the power supply frequencies of the power supply side of the power supply system at each moment from the current moment to the initial moment are obtained, and according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs, the power adjustment amount of each power device is determined. Then, according to the power adjustment amount of each power device, the output power of each power device is adjusted to control the power supply frequency on the grid side to be within the preset frequency range. In this method, when the frequency on the grid side of the power supply system changes, the power supply side will obtain the power supply frequencies at each moment after the moment when the change starts on the grid side, and then according to each power supply frequency at each moment and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs, the power distribution strategies corresponding to different adjustment stages are different, which ensures that when the power supply frequency on the grid side is adjusted, the change of the power supply frequency fluctuates less, improving the stability of the power supply; and, by using multiple power devices to jointly participate in power adjustment and using the power distribution strategies of each adjustment stage to adjust the power of each power device respectively, the power supply on the grid side can be kept within the preset range, ensuring the stability of the power supply system.

[0098] In one embodiment, as Figure 4 shown, before obtaining the power supply frequencies of the power supply side of the power supply system at each moment from the current moment to the initial moment, this embodiment includes the following steps:

[0099] S401, determining the time range of each adjustment stage according to the initial moment and the stage duration of a preset plurality of adjustment stages; the plurality of adjustment stages include a frequency modulation stage, a power compensation stage, and a voltage recovery stage.

[0100] According to the preset duration and initial time of each adjustment stage, determine the time range of each adjustment stage. For example, if the preset adjustment stages are set to 3, namely the frequency modulation stage, the power compensation stage, and the voltage recovery stage, the frequency modulation stage corresponds to the first power distribution strategy, the power compensation stage corresponds to the second power distribution strategy, and the voltage recovery stage corresponds to the third power distribution strategy. The stage duration of the frequency modulation stage is 3, the stage duration of the power compensation stage is 5, and the stage duration of the voltage recovery stage is 4. If the initial time is 1, then the frequency modulation stage should be between time 1 and time 4, the power compensation stage should be between time 4 and time 9, and the voltage recovery stage should be between time 9 and time 13.

[0101] It should be noted that for the values corresponding to the time and the preset duration in the embodiments of the present application, the time unit is not considered, and it is only for more clearly explaining the adjustment stage to which the current time belongs.

[0102] S402. Determine the adjustment stage to which the current time belongs according to the current time and the time range of each adjustment stage.

[0103] Based on the above embodiments, if the current time is 5, the frequency modulation stage is between time 1 and time 4, the power compensation stage is between time 4 and time 9, and the voltage recovery stage is between time 9 and time 13, then it is determined that the adjustment stage to which the current time belongs is the power compensation stage.

[0104] In the above frequency control method, the time range of each adjustment stage is determined according to the initial time and the stage duration of a plurality of preset adjustment stages. The plurality of adjustment stages include a frequency modulation stage, a power compensation stage, and a voltage recovery stage, and the adjustment stage to which the current time belongs is determined according to the current time and the time range of each adjustment stage. By dividing the frequency adjustment process on the grid side into multiple adjustment stages and adjusting the power of each power device through multiple adjustment stages, the fluctuation during the grid side power supply frequency adjustment can be made smaller, and the stability of the power supply system is improved.

[0105] In one embodiment, as Figure 5 shown, if the adjustment stage to which the current time belongs is the frequency modulation stage, obtain the power supply frequencies of the power supply side of the power supply system at each time between the current time and the initial time, including the following steps:

[0106] S501. Obtain the first power supply frequency change amount of the grid side of the power supply system at each time between the current time and the initial time and the voltage-frequency droop coefficient of the converter station on the grid side.

[0107] A frequency detection device is installed on the grid side of the power supply system. When the power supply frequency on the grid side changes, the frequency detection device can issue an early warning. Moreover, the frequency detection device can collect the power supply frequency on the grid side in real time and store the power supply frequency in the frequency database. Therefore, the power supply frequencies at each moment between the current moment and the initial moment when the power supply frequency changes can be obtained from the frequency database.

[0108] According to the power supply frequency at the initial moment, the first power supply frequency change amount at each moment between the current moment and the initial moment can be obtained. Specifically, the difference between the power supply frequency at each moment and the power supply frequency at the initial moment is calculated respectively to obtain the frequency change amount corresponding to each moment between the current moment and the initial moment, and the frequency change amount is determined as the first frequency change amount.

[0109] For example, if f n0 is the power supply frequency on the grid side at the initial moment and f n is the power supply frequency on the grid side at the current moment, then the first frequency change amount at the current moment is Δf n = f n - f n0 .

[0110] A converter station refers to a station established in a high-voltage DC power transmission system to complete the conversion of alternating current to direct current or direct current to alternating current and meet the requirements of the power supply system for safety, stability, and power quality. When transmitting current from the power source side to the grid side, the transmitted current is direct current. Therefore, when receiving on the grid side, the direct current can be converted to alternating current according to the converter station on the grid side.

[0111] Droop control selects a frequency primary droop characteristic curve (Droop Character) similar to that of a traditional generator as the control method for the micro-source, that is, stable frequency and voltage are obtained through f-U d droop control and U d -f droop control respectively. This control method controls the active power and reactive power output by the micro-source in the microgrid respectively, without the need for communication coordination between units, achieving the goals of plug-and-play and peer-to-peer control of the micro-source.

[0112] In order to enable the power supply system to respond to the change event of the power supply frequency on the grid side, the power supply system needs to be able to reflect the change of the power supply frequency on the grid side. Therefore, the converter station on the grid side adopts f-U d droop control. The f-U d droop control can change the DC bus voltage of the power supply system according to the change of the power supply frequency on the grid side. When detecting the change of the power supply frequency, the DC bus voltage should be obtained first.

[0113] To obtain the DC bus voltage through droop control, it is first necessary to obtain the voltage-frequency droop coefficient of the converter station on the grid side. Optionally, the voltage-frequency droop coefficient of the converter station on the grid side can be obtained from a pre-stored database, or it can be obtained through multiple tests to get the voltage-frequency droop coefficient corresponding to the optimal result.

[0114] S502. Determine the change in the DC bus voltage of the power supply system according to each first power supply frequency change amount and the voltage-frequency droop coefficient.

[0115] The change in the DC bus voltage of the power supply system can be calculated using Equation (1):

[0116] Δu = k on ·Δf n t < t w_re (1)

[0117] Where Δu is the change in the DC bus voltage of the power supply system, Δf n is the change in the first power supply frequency on the grid side, k on is the voltage-frequency droop coefficient; t is the current time, and t w_re is the next time after the termination time of the frequency modulation stage.

[0118] It should be noted that t and t in the following embodiments w_re are the same as the descriptions in this embodiment and will not be elaborated below.

[0119] S503. Determine the change in the second power supply frequency at each time from the current time to the initial time on the power supply side according to the change in the DC bus voltage and the frequency-voltage droop coefficient of the converter station on the power supply side.

[0120] The change in the second power supply frequency at each time from the current time to the initial time on the power supply side can be calculated using Equation (2):

[0121] Δf w = k off ·Δu t < t w_re (2)

[0122] Where Δf w is the change in the second power supply frequency on the power supply side, Δu is the change in the DC bus voltage of the power supply system, and k off is the frequency-voltage droop coefficient of the converter station on the power supply side; the frequency-voltage droop coefficient can be obtained from a preset frequency database.

[0123] S504. Determine the power supply frequency at each time from the current time to the initial time on the power supply side according to each second power supply frequency change amount and the initial power supply frequency at the initial time on the power supply side.

[0124] According to the change amount of the second power supply frequency of the power supply side at each moment from the current moment to the initial moment and the initial power supply frequency of the power supply side at the initial moment, calculate the power supply frequency of the power supply side at each moment from the current moment to the initial moment according to Equation (3):

[0125] f w = f w0 + Δf w t < t w_re (3)

[0126] Wherein, f w is the power supply frequency of the power supply side at each moment from the current moment to the initial moment, Δf w is the change amount of the second power supply frequency of the power supply side, f w0 is the initial power supply frequency of the power supply side at the initial moment, that is, the rated frequency of the power supply side.

[0127] In one embodiment, taking the power supply system as an offshore wind power - hydrogen energy system as an example, as Figure 6 shown,[[]]END]] Figure 6 is the basic structure diagram of the system. In this system, the grid side is the receiving - end AC system and the receiving - end converter station, and the power supply side is the sending - end converter station and the sending - end AC system. When the frequency of the receiving - end AC system changes, the receiving - end converter station adopting voltage - frequency droop control makes the DC bus voltage of the flexible DC transmission system change according to the change of the power supply frequency of the receiving - end AC system, as shown in Equation (1); the sending - end converter station adopting frequency - voltage droop control detects the change of the DC bus voltage and changes the frequency of the offshore AC system, as shown in Equation (2); Figure 6 Each power equipment in

[0128] includes a wind farm, an electrolyzer, a fuel cell, and an offshore load.

[0129] In one embodiment, as Figure 7As shown, according to the target power distribution strategy corresponding to each power supply frequency and the adjustment stage to which the current moment belongs, determining the power adjustment amount of each power device includes the following steps:

[0130] S701, according to each power supply frequency, calculate the frequency change rate between the current moment and the initial moment.

[0131] Based on the power supply frequencies at each moment from the current moment to the initial moment on the power supply side, calculate the frequency change rate at each moment. The calculation method of the frequency change rate at any moment can be, for example, if the initial moment is 1, the arbitrary moment is 5, the frequency at the initial moment is 50, and the power supply frequency at moment 5 is 60, then the frequency change rate at moment 5 is (60 - 50) / (5 - 1) = 2.5. Optionally, the frequency change rates at each moment between the current moment and the initial moment can all be calculated by this method.

[0132] S702, based on the droop control strategy, inertial response strategy, second power supply frequency change amount, frequency change rate, and the inertial control coefficients corresponding to each power device, determine the power adjustment amount of each power device; the inertial control coefficients include the droop coefficient and the inertial response coefficient.

[0133] The comprehensive inertial control includes two parts: virtual inertial control and droop control, which use the system frequency change rate and frequency deviation as input signals respectively. The former is mainly used to slow down the rapid change of the system frequency, and the latter is mainly used to reduce the frequency deviation. By introducing both the frequency deviation and the frequency change rate in the active power control link, the frequency adjustment ability of each power device is further improved.

[0134] For example, if the power devices include wind turbines, electrolyzers, and fuel cells, the method of using the comprehensive inertial control to calculate the wind turbines, electrolyzers, and fuel cells is as shown in equations (4)-(6).

[0135]

[0136] Among them, ΔP w is the power adjustment amount of the wind turbine; Δf w is the second power supply frequency change amount on the power supply side; k in_w and k f_w are the inertial response coefficient and droop coefficient of the wind turbine respectively, is the frequency change rate of the wind turbine; as Figure 8 shown, Figure 8 is the block diagram of the comprehensive inertial control strategy of the wind turbine. In Figure 8 , P MPPT is the power of the wind turbine in the normal operation mode. According to the power of the wind turbine in the normal operation mode and the power adjustment amount of the wind turbine, the actual power P W of the wind turbine can be obtained.

[0137] The electrolyzer and the fuel cell are connected to the AC power supply side by a DC / AC converter similar to that in a wind turbine. Therefore, during the frequency modulation stage before the rotor speed of the wind turbine recovers, this embodiment also adopts a comprehensive inertia response and frequency droop control strategy similar to that of the wind turbine to achieve the frequency control of the electrolyzer and the fuel cell.

[0138]

[0139] Among them, ΔP EL is the power adjustment amount of the electrolyzer; Δf w is the change amount of the second power supply frequency on the power supply side, and k in_w and k f_w are the inertia response coefficient and the droop coefficient of the electrolyzer respectively, is the frequency change rate of the electrolyzer.

[0140]

[0141] Among them, ΔP FC is the power adjustment amount of the fuel cell; Δf w is the change amount of the second power supply frequency of the fuel cell, and k in_w and k f_w are the inertia response coefficient and the droop coefficient of the fuel cell respectively, is the frequency change rate of the fuel cell.

[0142] In the above frequency control method, according to each power supply frequency, the frequency change rate between the current moment and the initial moment is calculated; based on the droop control strategy, the inertia response strategy, the change amount of the second power supply frequency, the frequency change rate, and the inertia control coefficients corresponding to each power device, the power adjustment amount of each power device is determined; the inertia control coefficients include the droop coefficient and the inertia response coefficient. In this method, during the frequency modulation stage, by the droop control strategy and the inertia response strategy, the power adjustment amount of each power device is calculated, which can make the fluctuation smaller when the power supply frequency on the grid side is adjusted, and improves the stability of the power supply system.

[0143] In one embodiment, as Figure 9 shown, if the adjustment stage to which the current moment belongs is the power compensation stage or the voltage recovery stage, obtaining the power supply frequencies of each moment between the current moment and the initial moment on the power supply side of the power supply system includes the following steps:

[0144] S901, send a power supply frequency acquisition instruction to the frequency detection device, and the frequency detection device is a device in the power supply system used to collect the power supply frequencies of each moment between the current moment and the initial moment.

[0145] A frequency detection device is a device capable of collecting frequencies. When the frequency detection device is installed on the power supply side of the power supply system, the power supply frequency on the power supply side can be obtained from the frequency detection device when needed.

[0146] Specifically, in the power compensation stage and the voltage recovery stage, a power supply frequency acquisition instruction can be sent to the frequency detection device. The power supply frequency acquisition instruction is used to acquire the power supply frequencies of the power supply side at each moment between the current moment and the initial moment collected by the frequency detection device.

[0147] Optionally, the frequency detection device can be a low-pass filter circuit, a peak detection circuit, a gain control circuit, a pulse acquisition circuit, etc.

[0148] S902. Receive the power supply frequencies of the power supply side at each moment between the current moment and the initial moment sent by the frequency detection device.

[0149] After receiving the power supply frequency acquisition instruction, the frequency detection device can send the acquired power supply frequencies of the power supply side at each moment between the current moment and the initial moment to the server, and the server receives the power supply frequencies of the power supply side at each moment between the current moment and the initial moment sent by the frequency detection device.

[0150] In this embodiment, the power supply frequency of the power supply side is obtained through the frequency detection device in the power compensation stage and the voltage recovery stage. Therefore, the power supply frequencies received by the server from the frequency detection device are the power supply frequencies at each moment in the power compensation stage and the voltage recovery stage.

[0151] In the above frequency control method, a power supply frequency acquisition instruction is sent to the frequency detection device. The frequency detection device is a device in the power supply system used to collect the power supply frequencies of the power supply side at each moment between the current moment and the initial moment, and the power supply frequencies of the power supply side at each moment between the current moment and the initial moment sent by the frequency detection device are received. In the power compensation stage and the voltage recovery stage, this method uses the frequency detection device to obtain the power supply frequency of the power supply side, improving the response speed of the power supply side and ensuring the timeliness of frequency adjustment on the grid side.

[0152] In one embodiment, as Figure 10 shown, if the adjustment stage to which the current moment belongs is the power compensation stage, then according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs, determine the power adjustment amount of each power device, including the following steps:

[0153] S1001. Obtain the minimum frequency in the frequency modulation stage from each power supply frequency.

[0154] After adopting the comprehensive inertia control strategy in the frequency modulation stage, taking the reduction of the power supply frequency on the grid side as an example, if the power device includes a wind turbine generator set, then in the frequency modulation stage, the wind turbine generator set will increase the output electromagnetic power ΔPw When the mechanical power of the wind turbine is less than the electromagnetic power, the rotor speed of the wind turbine will gradually decrease, and the rotor releases kinetic energy to participate in frequency regulation.

[0155] Therefore, during the power compensation stage, it is necessary to reduce the electromagnetic power of the wind turbine in the normal mode to restore the rotor speed of the wind turbine. During the rotor speed recovery period, it is necessary to keep the power of the wind turbine fixed for a certain period of time. After the fixed power duration, the output power of the wind turbine gradually increases to the normal power, and the increasing speed gradually decreases.

[0156] The fixed power duration is related to the additional energy released by the wind turbine during the frequency regulation stage. The more additional energy the wind turbine releases, the greater the fixed power duration; when the lowest power supply frequency on the power supply side during the frequency regulation stage is lower, the power of the wind turbine is correspondingly greater and the energy provided is also more. Therefore, the fixed power duration can be approximately reflected by the lowest power supply frequency on the power supply side during the frequency regulation stage.

[0157] Therefore, before obtaining the fixed power duration, that is, the fixed power compensation time, it is necessary to obtain the lowest frequency point (minimum frequency) of the power supply side during the frequency regulation stage.

[0158] Based on the power supply frequency obtained in the above embodiment during the frequency regulation stage, determine the minimum power supply frequency during the frequency regulation stage, that is, the minimum frequency during the frequency regulation stage.

[0159] S1002. Determine the fixed power compensation time of the power compensation stage according to the minimum frequency and the preset time-frequency coefficient.

[0160] According to the minimum frequency obtained above during the frequency regulation stage and the preset time-frequency coefficient, the fixed power compensation time of the power compensation stage can be obtained, as shown in Equation (7).

[0161] Δt w_sup =K w_re f wmin (7)

[0162] Where, Δt w_sup is the fixed power compensation time of the power compensation stage, K w_re is the time-frequency coefficient, and f wmin is the minimum frequency of the power supply side during the frequency regulation stage.

[0163] S1003. Determine the total power value that each power equipment needs to adjust according to the fixed power compensation time.

[0164] Based on the obtained fixed power compensation time above, determine the total power value that each power device needs to adjust. Since the power compensation stage is a process of the rotor speed recovery of the wind turbine generator set, at this time, if the output power of the wind turbine generator set decreases or increases, it will cause the imbalance of the power supply system and the secondary drop of the frequency. Therefore, it is necessary to use power devices to adjust the power to compensate for the increased or decreased power of the wind turbine generator set.

[0165] For example, if the frequency on the grid side decreases, the wind turbine generator set increases its output power during the frequency regulation stage, the rotor releases kinetic energy to participate in frequency regulation, and the rotor speed decreases. During the power compensation stage, the rotor speed of the wind turbine generator set is restored, and the output power of the wind turbine generator set decreases. At this time, in order to maintain the stability of the power supply system, the power of other power devices is increased, and the increased power value is the total power value that each power device needs to adjust.

[0166] Therefore, based on the fixed power compensation time, the total power value that each power device needs to adjust can be determined according to a preset determination algorithm.

[0167] Taking the power devices including wind turbine generator sets, electrolyzers and fuel cells as an example, determine the total power value that each power device needs to adjust.

[0168] In one embodiment, set the first preset moment as the starting moment of the power compensation stage, the difference between the second preset moment and the first preset moment is the fixed power compensation time; the third preset moment is the ending moment of the power compensation stage; the second preset moment is less than the third preset moment.

[0169] If the current moment is greater than or equal to the first preset moment and less than or equal to the second preset moment, then set the preset fixed compensation power as the total power value that multiple power devices need to adjust.

[0170] If the current moment is greater than the second preset moment and less than or equal to the third preset moment, determine the total power values that the wind turbine generator set, the electrolyzer and the fuel cell need to adjust through the functional relationship among the current moment, the second preset moment, the third preset moment, the fixed compensation power, and the total power value; the functional relationship is constructed according to the characteristics of the wind turbine generator set during the power compensation stage.

[0171] During the power compensation stage, the total power P that the wind turbine generator set, the fuel cell and the electrolyzer need to adjust w_sup can be calculated by Equation (8).

[0172]

[0173] Among them, t w_re is the first preset moment, that is, the starting moment of the power compensation stage, and also the moment when the rotor speed of the wind turbine generator set is restored. Δt w_supThe fixed power compensation time, t, in the power compensation stage W-re +Δt w_sup is the second preset moment, t w_sup is the third preset moment, i.e., the termination moment of the power compensation stage, ΔP w_sup is the preset fixed compensation power.

[0174] If the current moment is greater than or equal to t w_re , and less than or equal to t w_re +Δt w_sup , then ΔP w_sup is determined as the total power value that needs to be adjusted for the wind turbine, electrolyzer, and fuel cell.

[0175] If the current moment is greater than t w_re +Δt w_sup , and less than or equal to t w_sup , the total power value that needs to be adjusted for the wind turbine, electrolyzer, and fuel cell at each moment is calculated according to the functional relationship (see Equation (8)) constructed based on the characteristics of the wind turbine in the power compensation stage.

[0176] Among them, the compensation power ΔP w_sup is a preset value. In this embodiment, it is set that ΔP w_sup is equal to the preset fixed reduction power ΔP w_re when the rotor speed of the wind turbine starts to recover. In the high wind speed section of the frequency modulation stage of the wind turbine, when the wind speed is low, the output ratio of synchronous units in the entire power supply system is high, the inertia of the power supply system is strong, the power supply frequency drop on the power supply side is low, and the energy released additionally by the wind turbine in the frequency modulation stage is low. Therefore, when the wind speed is low, the preset values of ΔP w_re and ΔP w_sup should be reduced accordingly. Optionally, the method of looking up a table can be used to set ΔP w_re and ΔP w_sup at different wind speeds.

[0177] After the second preset moment, the power compensation value gradually decreases and is close to t w_sup the power compensation value is already very small. Therefore, t w_sup has a relatively small impact on the power supply frequency on the grid side. In this embodiment, it can be set as the moment t u_re when the flexible DC voltage recovery starts, that is, the starting moment of the voltage recovery stage.

[0178] S1004. Determine the power adjustment amount of each power equipment according to the total power value.

[0179] Based on the above total power value, the power adjustment amount can be reasonably distributed among the wind turbine generator, the electrolyzer, and the fuel cell. The total power value can be distributed according to the remaining capacities of the electrolyzer and the fuel cell. In one embodiment, the electrolyzer and the fuel cell give priority to outputting power. If the remaining capacities of the electrolyzer and the fuel cell are sufficient, the total power value is distributed to the electrolyzer and the fuel cell. If the remaining capacities of the electrolyzer and the fuel cell are insufficient, such as when the fuel cell is fully loaded and the electrolyzer is idle, the wind turbine generator will reduce its load. That is, when the remaining capacities of the electrolyzer and the fuel cell are insufficient, the wind turbine generator will jointly distribute the total power value with the electrolyzer and the fuel cell.

[0180] The following uses an embodiment to illustrate how to distribute the power adjustment amount of the total power value required to be adjusted by the wind turbine generator, the electrolyzer, and the fuel cell according to the remaining capacities of the electrolyzer and the fuel cell. In one embodiment, first, obtain the remaining capacity of the electrolyzer and the remaining capacity of the fuel cell.

[0181] Secondly, if the sum of the remaining capacity of the electrolyzer and the remaining capacity of the fuel cell is greater than or equal to the fixed compensation power, then according to the remaining capacity of the electrolyzer, the remaining capacity of the fuel cell, and the total power value, determine the power adjustment amounts of the electrolyzer and the fuel cell, and determine that the power adjustment amount of the wind turbine generator is 0.

[0182] If the sum of the remaining capacity of the electrolyzer and the remaining capacity of the fuel cell is less than the fixed compensation power, then according to the remaining capacity of the electrolyzer, the fixed compensation power, and the total power value, determine the power adjustment amount of the electrolyzer; according to the remaining capacity of the fuel cell, the fixed compensation power, and the total power value, determine the power adjustment amount of the fuel cell; and according to the total power value, the power adjustment amount of the electrolyzer, and the power adjustment amount of the fuel cell, determine the power adjustment amount of the wind turbine generator.

[0183] Before the rotor speed of the wind turbine generator recovers, if the remaining capacity of the electrolyzer is and the remaining capacity of the fuel cell is

[0184] When , the power adjustment amount of the wind turbine generator is 0, and the electrolyzer and the fuel cell can supply all the energy required for the rotor speed recovery of the wind turbine generator. The power adjustment amount ΔP el_w of the electrolyzer and the power adjustment amount ΔP fc_w of the fuel cell are distributed according to and , as shown in Equation (9).

[0185]

[0186] When , the wind turbine generator needs to reduce its load. Let its load reduction power be P de_w , then

[0187]

[0188] ΔP de_w = P sup_w -ΔP el_w -ΔP fc_w (11)

[0189] wherein, P w_sup is the total power that needs to be adjusted for the wind turbine, fuel cell and electrolyzer during the power compensation stage, and ΔP de_w is the power adjustment amount of the wind turbine, and ΔP el_w is the power adjustment amount of the electrolyzer, and ΔP fc_w is the power adjustment amount of the fuel cell, is the remaining capacity of the electrolyzer, is the remaining capacity of the fuel cell.

[0190] In the above frequency control method, the minimum frequency in the frequency modulation stage is obtained from each power supply frequency, and according to the minimum frequency and the preset time-frequency coefficient, the fixed power compensation time in the power compensation stage is determined, and according to the fixed power compensation time, the total power value that each power equipment needs to adjust is determined; the power adjustment amount of each power equipment is determined according to the total power value. In this method, first, the total power value that each power equipment needs to adjust in the power compensation stage of the grid-side frequency control is determined, and then the total power value is allocated to each power equipment, ensuring the stability of the power supply system during the grid-side power supply frequency control process.

[0191] In one embodiment, as Figure 11 shown, if the adjustment stage to which the current moment belongs is the voltage recovery stage; then according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs, the power adjustment amount of each power equipment is determined, including the following steps:

[0192] S1101, obtain the power supply frequency at the third preset moment, and calculate the third power supply frequency change amount of the power supply side from the third preset moment to the initial moment according to the power supply frequency at the third preset moment; the third preset moment is the end moment of the power compensation stage.

[0193] The end moment of the power compensation stage is also the moment when the flexible DC system in the power supply system starts to recover, that is, the start moment t u_re of the voltage recovery stage, and t u_re is related to the input time of the frequency modulation device and can be set to a fixed value.

[0194] When the bus voltage of the flexible DC system recovers, it is actually charging the capacitor of the flexible DC system. Before the DC bus voltage recovers, it is necessary to calculate the frequency deviation value of the power supply side compared with the initial moment.

[0195] Therefore, first obtain the power supply frequency on the power supply side at the third preset moment, and then calculate the third power supply frequency change amount from the third preset moment to the initial moment according to the power supply frequency at the third preset moment and the rated frequency on the power supply side at the initial moment; subtract the rated frequency on the power supply side at the initial moment from the power supply frequency at the third preset moment to obtain the third power supply frequency change amount.

[0196] The third power supply frequency change amount represents the frequency deviation value between the power supply side and the initial moment after the end of the power compensation stage and before the start of the voltage recovery stage, and this frequency deviation value is the frequency value that needs to be adjusted at the voltage recovery moment.

[0197] S1102. Determine the voltage offset amount of the DC bus from the third preset moment to the initial moment according to the third power supply frequency change amount and the frequency-voltage droop coefficient.

[0198] The method for determining the voltage offset amount of the DC bus from the third preset moment to the initial moment is shown in Equation (12).

[0199]

[0200] Among them, is the voltage offset amount of the DC bus from the third preset moment to the initial moment, is the third power supply frequency change amount of the power supply side from the third preset moment to the initial moment, and k off is the frequency-voltage droop coefficient of the converter station on the power supply side.

[0201] S1103. Determine the total power value that each power equipment needs to adjust according to the slope of the DC bus voltage recovery and the voltage offset amount.

[0202] The total power value that each power equipment needs to adjust can be determined through a preset adjustment algorithm. Specifically, take the slope of the DC bus voltage recovery and the voltage offset amount as the input of the adjustment algorithm, and by running this adjustment algorithm, finally directly output the total power amount that the wind turbine, electrolyzer, and fuel cell need to adjust.

[0203] S1104. Determine the adjustment amount of each power equipment according to the total power value.

[0204] In the voltage recovery stage, after obtaining the total power value as described above, the method for determining the adjustment amount of each power equipment according to the total power value can be the same as the method for obtaining the power adjustment amount of each power equipment according to the total power value in the power compensation stage, and it is also determined by the remaining capacity of the electrolyzer and the fuel cell.

[0205] Specifically, obtain the remaining capacity of the electrolyzer and the remaining capacity of the fuel cell; secondly, if the sum of the remaining capacity of the electrolyzer and the remaining capacity of the fuel cell is greater than or equal to the fixed compensation power in the power compensation stage, then determine the power adjustment amounts of the electrolyzer and the fuel cell according to the remaining capacity of the electrolyzer, the remaining capacity of the fuel cell, and the total power value, and determine that the power adjustment amount of the wind turbine is 0.

[0206] If the sum of the remaining capacity of the electrolyzer and the remaining capacity of the fuel cell is less than the fixed compensation power, then determine the power adjustment amount of the electrolyzer according to the remaining capacity of the electrolyzer, the fixed compensation power, and the total power value; determine the power adjustment amount of the fuel cell according to the remaining capacity of the fuel cell, the fixed compensation power, and the total power value; and determine the power adjustment amount of the wind turbine according to the total power value, the power adjustment amount of the electrolyzer, and the power adjustment amount of the fuel cell.

[0207] The specific calculation methods for determining the power adjustment amounts of the wind turbine, the electrolyzer, and the fuel cell according to the remaining capacities of the electrolyzer and the fuel cell and the total power value are the same as those in the above formulas (9)-(11), and will not be elaborated in this embodiment.

[0208] In the above frequency control method, obtain the power supply frequency at the third preset moment, and calculate the third power supply frequency change amount of the power supply side from the third preset moment to the initial moment. The third preset moment is the end moment of the power compensation stage. Then, determine the voltage offset amount of the DC bus from the third preset moment to the initial moment according to the third power supply frequency change amount and the frequency-voltage droop coefficient. According to the slope of the DC bus voltage recovery and the voltage offset amount, determine the total power value that each power device needs to adjust. Finally, determine the adjustment amount of each power device according to the total power value. In this method, by calculating the frequency offset amount that needs to be restored in the voltage recovery stage, and then determining the voltage offset amount according to the frequency offset amount, the total power value that each power device needs to adjust in the voltage recovery stage is calculated, and then the power adjustment amount of each power device is calculated, which reasonably distributes the total power value among each power device and ensures the stability of the power supply system during the power supply frequency control on the grid side.

[0209] In one embodiment, as Figure 12 shown, determining the total power value that each power device needs to adjust according to the slope of the DC bus voltage recovery and the voltage offset amount includes the following steps:

[0210] S1201, determine the duration of the voltage recovery of the power supply side according to the slope of the DC bus voltage recovery and the voltage offset amount.

[0211] The duration of voltage recovery during the voltage adjustment phase can be calculated based on the voltage offset and the slope of the DC bus voltage recovery. The duration of voltage recovery is also the duration for which additional power is generated during the voltage recovery phase.

[0212] The method for determining the duration of voltage recovery on the power supply side can be calculated using Equation (13).

[0213]

[0214] Where, Δt u_re is the duration of voltage recovery on the power supply side, and k u_re is the slope of the DC bus voltage recovery, is the voltage offset.

[0215] S1202. Determine the total amount of electricity that needs to be adjusted for each power device during the voltage recovery process in the power supply system based on the rated capacitance of the DC bus, the slope, and the voltage of the DC bus at the third preset moment.

[0216] When recovering the voltage, it is actually charging the capacitance of the DC bus of the flexible DC system. Therefore, it is necessary to calculate the change in the charge of the capacitance before voltage recovery, that is, the total amount of electricity that needs to be adjusted for each power device during the voltage recovery process in the power supply system.

[0217] The method for calculating the total amount of electricity that needs to be adjusted for each power device during the voltage recovery process can be calculated according to Equation (14).

[0218]

[0219] Where, ΔE dc is the total amount of electricity that needs to be adjusted for each power device during the voltage recovery process, C dc is the rated capacitance of the DC bus, is the voltage of the DC bus at the third preset moment before the voltage recovery phase, and k u_re is the slope of the voltage recovery.

[0220] S1203. Determine the total power value that needs to be adjusted for each power device based on the total amount of electricity and the duration of voltage recovery.

[0221] The method for determining the total power value that needs to be adjusted for each power device can be calculated using Equation (15).

[0222]

[0223] Where, P u_sup is the total power value that needs to be adjusted for each power device, ΔE dc is the total amount of electricity that needs to be adjusted for each power device during the voltage recovery process, and Δt u_reThe duration for the power supply side to perform voltage recovery, t u_re is the third preset time.

[0224] In the above frequency control method, according to the slope of the DC bus voltage recovery and the voltage offset, the duration for the power supply side to perform voltage recovery is determined; according to the rated capacitance of the DC bus, the slope, and the voltage of the DC bus at the third preset time, the total amount of electricity that needs to be adjusted for each power device during the voltage recovery process in the power supply system is determined; according to the total amount of electricity and the duration of voltage recovery, the total power value that needs to be adjusted for each power device is determined. This method ensures the stability of the power supply system during the power grid side power supply frequency control process.

[0225] In one embodiment. Please continue to refer to Figure 8 , when performing the comprehensive inertia control and rotor speed recovery control of the wind turbine, the calculated power adjustment amount of the wind turbine is the same. After obtaining the adjustment amount of the wind turbine, the actual power value of the wind turbine can be calculated using Equation (16).

[0226]

[0227] Among them, P w is the actual power value of the wind turbine, is the power of the wind turbine at the initial moment when operating in the Maximum Power Point Tracking (MPPT) mode. The MPPT mode is a normal operating state of the wind turbine. ΔP w is the power adjustment amount of the wind turbine during the frequency modulation stage. ΔP w_re is the power adjustment amount during the fixed power compensation in the power compensation stage. t is the current time, and t w_re is the start time of the power compensation stage. Δt sup is the fixed power compensation duration.

[0228] In one embodiment, if the power supply frequency on the power grid side can return to normal, according to the above comprehensive inertia control strategy, the DC bus voltage will automatically recover. However, if the secondary frequency modulation equipment on the power grid side is not put into operation in time, the power supply frequency deviation and the DC bus voltage deviation between the power supply side and the power grid side will continue, reducing the operating efficiency of the power supply system. Therefore, it is necessary to preset a duration after the power supply frequency event on the power grid side to make the voltage of the DC bus return to normal. The slope recovery strategy can be used to recover the DC bus voltage at time t u_re , as shown in Equation (17).

[0229]

[0230] Among them, u dc is the actual voltage value, and k u_reis the slope of voltage recovery, t u_re is the start time of the voltage recovery stage, is the voltage at the start time of the voltage recovery stage, and t is the current time.

[0231] In one embodiment, as Figure 13 shown, the figure includes the power change amount of the wind turbine generator set, as well as the total power adjustment amounts of the wind turbine generator set, the electrolyzer and the fuel cell, t w_re to t w_sup is the power compensation stage, and t w_sup to t w_re1 is the voltage recovery stage. After the power supply frequency on the grid side changes, the change amount of the output electromagnetic power of the wind turbine generator set is as Figure 13 shown. Between t w_re and t w_re +Δt w_re is the fixed compensation power stage of the power compensation stage, where the power of the wind turbine generator set is almost unchanged and the power difference remains ΔP w_re ; between t w_re +Δt w_re and t w_re1 , the output power of the wind turbine generator set gradually increases to the normal power, and the increasing speed gradually decreases; and the compensated power ΔP w_sup of the wind turbine generator set, the electrolyzer and the fuel cell is set to be equal to ΔP w_re . Δt w_re and t w_re1 are related to the wind speed, the initial frequency event, and the characteristics of the wind turbine generator set and the external system.

[0232] In one embodiment, taking the offshore wind power - hydrogen energy system as an example for the power supply system, overall, the control framework for the offshore wind power - hydrogen energy system to participate in primary frequency modulation is as Figure 14 shown. When the onshore load power suddenly increases by ΔP Lon , the speed of the conventional synchronous generator set changes, resulting in a change of Δf n in the onshore grid side frequency. At the same time, the governor in the conventional synchronous generator set detects the frequency change, and the synchronous generator set performs primary frequency modulation. The onshore converter station using f - U droop control changes the DC bus voltage of the flexible DC transmission system by Δu dc according to the onshore grid side frequency change; the offshore converter station using U - f droop control detects the change of Δu dc and changes the offshore AC system frequency by Δf w . After that, the offshore wind turbine generator set, the electrolyzer, and the fuel cell adjust their own powers according to Δf w using the strategy in this application; at the same time, the power of the offshore load with a load - damping constant of D off changes by an amount of ΔP LoffFinally, the power change ΔP of the offshore wind power - hydrogen energy system off is injected into the flexible DC transmission system, transmitted to the synchronous machine side, and participates in the primary frequency regulation of the onshore power grid.

[0233] It should be noted that Figure 14 the parameters in are the same as those described in the above embodiments, and will not be elaborated here.

[0234] In one embodiment, the frequency control method in this application is simulated and compared with three cases: no frequency regulation, wind turbines and flexible DC systems participating in frequency regulation, and electrolyzers, fuel cells and flexible DC systems participating in frequency regulation through the offshore wind power - hydrogen energy system.

[0235] First, as shown in Table 1, the basic parameters of the offshore wind farm and the receiving system in the offshore wind power - hydrogen energy system are set. Table 2 shows the basic parameters of the Voltage Source Converter based High Voltage Direct Current Transmission (VSC - HVDC), and Table 3 shows the basic parameters of the electrolyzer and the fuel cell.

[0236] Table 1

[0237] Parameter Value Rated capacity of offshore wind farm 300MW Rated wind speed 12m / s Rated speed 1.1pu Rotor speed range of wind turbine 0.4 - 1.2pu Inertia response coefficient and droop coefficient of wind turbine 10，10 Offshore load capacity 20MW Offshore load - damping constant 2％ Rated capacity of receiving - end synchronous unit 400MW Droop coefficient of synchronous unit 8％ Onshore load capacity 360MW

[0238] Table 2

[0239] Parameter Value Rated power of VSC converter station 300MW Rated frequency 50Hz Droop coefficient of VSC converter station 1,1.6 DC bus voltage recovery coefficient 0.01pu / s

[0240] Table 3

[0241]

[0242]

[0243] To verify the effectiveness of the primary frequency regulation strategy of the offshore wind power - hydrogen energy system proposed in this application, 3 frequency regulation strategies are designed for comparative analysis, as shown in Table 4. The initial wind speed is set to 11 m / s, the initial power of the electrolyzer is set to 10 MW, and the initial power of the fuel cell is set to 0 MW. It is assumed that the frequency event is a sudden increase in the onshore load by 50 MW at the 20th second, the system frequency drops, and each device starts to participate in frequency regulation. The VSC converter station starts voltage recovery at the 55th second. The simulation curves of the grid - side frequency under each strategy are as Figure 15As shown, it can be seen that after the wind turbine participates in frequency regulation, the maximum value of the system frequency drop in Strategy 2 is significantly reduced compared to the case without frequency regulation. At the same time, during the rotor speed recovery period in Strategy 2, the wind turbine reduces its load, resulting in a significantly smaller secondary frequency drop compared to Strategy 1. In Strategy 3, the electrolyzer and fuel cell participate in frequency regulation separately, and the maximum frequency drop is smaller than that of Strategy 2, indicating that under the initial conditions of this application, the electrolyzer and fuel cell have a relatively strong ability to participate in primary frequency regulation. In Strategy 4, all devices in the system participate in primary frequency regulation, so the maximum frequency drop value is the smallest. At the same time, compared to Strategy 3, in Strategy 4, the electrolyzer and fuel cell provide power support during the rotor speed recovery period (29.5 - 55 s), resulting in a smaller secondary frequency drop in Strategy 4. During the VSC voltage recovery stage, Strategies 2, 3, and 4 all provide effective power support, making the frequency change amplitude very small.

[0244] Table 4

[0245]

[0246] During the simulation process, the powers of the wind turbine, electrolyzer, and fuel cell are as Figure 16 shown. During the temporary frequency support stage (frequency regulation stage) (20 - 29.5 s), only the wind turbine in Strategy 2 provides additional energy; in Strategy 3, the electrolyzer reduces its power and the fuel cell increases its power to provide additional energy; in the strategies proposed in this application, all devices provide additional energy simultaneously. During the rotor speed recovery stage (power compensation stage) (29.5 s - 55 s), in the strategies proposed in this application, since the remaining capacities of the electrolyzer and fuel cell are sufficient, the speed recovery compensation power is entirely borne by the two, and the wind turbine will not reduce its load; during the VSC voltage recovery stage (> 55 s), the required energy is still provided by the electrolyzer and fuel cell.

[0247] It can be seen that the primary frequency regulation strategy of the offshore wind power - hydrogen energy system proposed in this application has good effects, reasonably distributes the powers of the wind turbine, electrolyzer, and fuel cell, and makes the maximum frequency deviation and the frequency changes during rotor speed recovery and VSC voltage recovery relatively small.

[0248] In one embodiment, as Figure 17 shown, taking the power supply system as an offshore wind power - hydrogen energy system as an example, this embodiment includes the following steps:

[0249] S1701, Obtain the frequency change amount of the receiving - end AC system, and calculate the change amount of the DC bus voltage according to the frequency change amount of the receiving - end AC system.

[0250] S1702, Calculate the frequency change amount of the offshore AC system according to the change amount of the DC bus voltage.

[0251] S1703. When the current moment is in the frequency modulation stage, adopt the comprehensive inertia control strategy to calculate the power adjustment amounts of the wind turbine generator, electrolyzer, and fuel cell.

[0252] S1704. If the current moment is in the power compensation stage, calculate the total power value that needs to be adjusted for the wind turbine generator, electrolyzer, and fuel cell.

[0253] Among them, first calculate the fixed power compensation time in the power compensation stage according to the lowest frequency point in the frequency modulation stage, and calculate the total power value at each moment according to the fixed power compensation time.

[0254] S1705. Allocate the total power value according to the remaining capacities of the electrolyzer and fuel cell to determine the respective power adjustment amounts of the wind turbine generator, electrolyzer, and fuel cell.

[0255] S1706. When the current moment is in the voltage recovery stage, calculate the voltage deviation of the DC bus according to the frequency deviation of the wind farm side, and calculate the duration of the additional power generation of the power supply side according to the voltage change amount and the slope of the voltage recovery.

[0256] S1707. Calculate the change amount of the electric field energy stored in the DC capacitor corresponding to the voltage recovery of the flexible DC system, and calculate the total additional power value of the wind turbine generator, electrolyzer, and fuel cell in the voltage recovery stage according to the duration of the additional power generation and the change amount of the electric field energy stored in the DC capacitor.

[0257] S1708. According to the total power value, adopt the power allocation strategy in step S1705 to allocate the power of the wind turbine generator, electrolyzer, and fuel cell during the voltage recovery of the flexible DC system.

[0258] For the specific limitations of the frequency control method provided in this embodiment, reference can be made to the step limitations of each embodiment in the frequency control method described above, which will not be elaborated here.

[0259] It should be understood that although the steps in the flowcharts attached in the above embodiments are shown in sequence according to the arrows, these steps do not necessarily need to be executed in the order indicated by the arrows. Unless there is a clear description in this article, there is no strict order limit for the execution of these steps, and these steps can be executed in other orders. Moreover, at least a part of the steps in the figures attached in the above embodiments may include multiple steps or multiple stages. These steps or stages do not necessarily need to be executed at the same moment, but can be executed at different moments. The execution order of these steps or stages does not necessarily need to be sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0260] In one embodiment, as Figure 18As shown in the figure, an embodiment of the present application further provides a frequency control device 1800, which includes: an acquisition module 1801, a distribution module 1802, and an adjustment module 1803, where:

[0261] The acquisition module 1801 is configured to acquire the power supply frequencies of the power supply side of the power supply system at each moment between the current moment and the initial moment; the power supply side includes a plurality of power devices; the initial moment represents the moment when the power supply frequency of the grid side of the power supply system starts to change;

[0262] The distribution module 1802 is configured to determine the power adjustment amount of each power device according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs; among them, the power distribution strategies corresponding to each adjustment stage are different;

[0263] The adjustment module 1803 is configured to adjust the output power of each power device according to the power adjustment amount of each power device to control the power supply frequency of the grid side within a preset frequency range.

[0264] In one embodiment, the device 1800 further includes:

[0265] The first determination module is configured to determine the time range of each adjustment stage according to the initial moment and the stage duration of a preset plurality of adjustment stages; the plurality of adjustment stages include a frequency modulation stage, a power compensation stage, and a voltage recovery stage;

[0266] The second determination module is configured to determine the adjustment stage to which the current moment belongs according to the current moment and the time range of each adjustment stage.

[0267] In one embodiment, the acquisition module 1801 includes:

[0268] The first acquisition unit is configured to acquire the first power supply frequency change amount of the grid side of the power supply system at each moment between the current moment and the initial moment and the voltage-frequency droop coefficient of the converter station on the grid side;

[0269] The first determination unit is configured to determine the change amount of the DC bus voltage of the power supply system according to each first power supply frequency change amount and the voltage-frequency droop coefficient;

[0270] The second determination unit is configured to determine the second power supply frequency change amount of the power supply side at each moment between the current moment and the initial moment according to the change amount of the DC bus voltage and the frequency-voltage droop coefficient of the converter station on the power supply side;

[0271] The third determination unit is configured to determine the power supply frequency of the power supply side at each moment between the current moment and the initial moment according to each second power supply frequency change amount and the initial power supply frequency of the power supply side at the initial moment.

[0272] In one embodiment, the allocation module 1802 includes:

[0273] A calculation unit, configured to calculate a frequency change rate between the current moment and the initial moment according to each power supply frequency;

[0274] A fourth determination unit, configured to determine a power adjustment amount for each power device based on a droop control strategy, an inertia response strategy, a second power supply frequency change amount, a frequency change rate, and an inertia control coefficient corresponding to each power device; the inertia control coefficient includes a droop coefficient and an inertia response coefficient.

[0275] In one embodiment, the acquisition module 1801 includes:

[0276] A sending unit, configured to send a power supply frequency acquisition instruction to a frequency detection device, where the frequency detection device is a device in the power supply system for collecting the power supply frequencies at each moment between the current moment and the initial moment on the power supply side;

[0277] A receiving unit, configured to receive the power supply frequencies at each moment between the current moment and the initial moment on the power supply side sent by the frequency detection device.

[0278] In one embodiment, the allocation module 1802 includes:

[0279] A second acquisition unit, configured to acquire the minimum frequency in the frequency modulation stage from each power supply frequency;

[0280] A fifth determination unit, configured to determine a fixed power compensation time in the power compensation stage according to the minimum frequency and a preset time-frequency coefficient;

[0281] A sixth determination unit, configured to determine a total power value to be adjusted for each power device according to the fixed power compensation time;

[0282] A seventh determination unit, configured to determine a power adjustment amount for each power device according to the total power value.

[0283] In one embodiment, the sixth determination unit includes:

[0284] A first determination subunit, configured to, if the current moment is greater than or equal to a first preset moment and less than or equal to a second preset moment, determine a preset fixed compensation power as the total power value to be adjusted for multiple power devices; the first preset moment is the starting moment of the power compensation stage, and the difference between the second preset moment and the first preset moment is the fixed power compensation time;

[0285] A second determination subunit, configured to, if the current moment is greater than a second preset moment and less than or equal to a third preset moment, determine the total power value that needs to be adjusted for the wind turbine, the electrolyzer, and the fuel cell according to the functional relationship among the current moment, the second preset moment, the third preset moment, the fixed compensation power, and the total power value; the third preset moment is the end moment of the power compensation stage; the second preset moment is less than the third preset moment; the functional relationship is constructed according to the characteristics of the wind turbine during the power compensation stage.

[0286] In one embodiment, the seventh determination unit includes:

[0287] A first acquisition subunit, configured to acquire the remaining capacity of the electrolyzer and the remaining capacity of the fuel cell;

[0288] A third determination subunit, configured to, if the sum of the remaining capacity of the electrolyzer and the remaining capacity of the fuel cell is greater than or equal to the fixed compensation power, determine the power adjustment amounts of the electrolyzer and the fuel cell according to the remaining capacity of the electrolyzer, the remaining capacity of the fuel cell, and the total power value, and determine that the power adjustment amount of the wind turbine is 0;

[0289] A fourth determination subunit, configured to, if the sum of the remaining capacity of the electrolyzer and the remaining capacity of the fuel cell is less than the fixed compensation power, determine the power adjustment amount of the electrolyzer according to the remaining capacity of the electrolyzer, the fixed compensation power, and the total power value; determine the power adjustment amount of the fuel cell according to the remaining capacity of the fuel cell, the fixed compensation power, and the total power value; and determine the power adjustment amount of the wind turbine according to the total power value, the power adjustment amount of the electrolyzer, and the power adjustment amount of the fuel cell.

[0290] In one embodiment, the allocation module 1802 includes:

[0291] A third acquisition unit, configured to acquire the power supply frequency at the third preset moment and calculate the third power supply frequency change amount of the power supply side from the third preset moment to the initial moment; the third preset moment is the end moment of the power compensation stage;

[0292] A voltage offset unit, configured to determine the voltage offset amount of the DC bus from the third preset moment to the initial moment according to the third power supply frequency change amount and the frequency-voltage droop coefficient;

[0293] An eighth determination unit, configured to determine the total power value that needs to be adjusted for each power device according to the slope of the DC bus voltage recovery and the voltage offset amount;

[0294] A ninth determination unit, configured to determine the adjustment amounts of each power device according to the total power value.

[0295] In one of the embodiments, the eighth determination unit includes:

[0296] A fifth determination subunit, configured to determine the duration for voltage recovery on the power supply side according to the slope of the DC bus voltage recovery and the voltage offset;

[0297] A sixth determination subunit, configured to determine the total amount of electricity that needs to be adjusted for each power device during the voltage recovery process in the power supply system according to the rated capacitance of the DC bus, the slope, and the voltage of the DC bus at a third preset moment;

[0298] A seventh determination subunit, configured to determine the total power value that needs to be adjusted for each power device according to the total amount of electricity and the duration of voltage recovery.

[0299] For the specific limitations of the frequency control device, reference can be made to the limitations of each step in the frequency control method described above, which will not be elaborated here. Each module in the above frequency control device can be implemented in whole or in part by software, hardware, and their combinations. The above modules can be embedded in the target device in hardware form or independent of the target device, or stored in the memory of the target device in software form, so that the target device can call and execute the operations corresponding to the above modules.

[0300] In one embodiment, a computer device is provided, as Figure 19 shown. The computer device includes a processor, a memory, a communication interface, a display screen, and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements a frequency control method. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, a trackball, or a touchpad provided on the housing of the computer device, or an external keyboard, touchpad, or mouse, etc.

[0301] Those skilled in the art can understand that the above structural description of the computer device only relates to some structures related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0302] In one embodiment, a computer device is further provided, which includes a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, the steps in the above method embodiments are implemented.

[0303] For each step implemented by the processor in this embodiment, its implementation principle and technical effect are similar to those of the above frequency control method, and will not be elaborated here.

[0304] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0305] For each step implemented when the computer program in this embodiment is executed by the processor, its implementation principle and technical effect are similar to those of the above frequency control method, and will not be elaborated here.

[0306] In one embodiment, a computer program product is provided, which includes a computer program. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0307] For each step implemented when the computer program in this embodiment is executed by the processor, its implementation principle and technical effect are similar to those of the above frequency control method, and will not be elaborated here.

[0308] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data that have been authorized by the user or fully authorized by all parties.

[0309] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FRAM), phase change memories (PCM), graphene memories, etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0310] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0311] The above-described embodiments merely represent several implementation manners of the present application. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A frequency control method, characterized in that, The method includes: Obtaining the power supply frequencies of the power supply side of the power supply system at each moment between the current moment and the initial moment; the power supply side includes a plurality of power devices; the initial moment represents the moment when the power supply frequency of the grid side of the power supply system starts to change; Determining the power adjustment amount of each power device according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs; wherein, the power distribution strategy corresponding to each adjustment stage is different; Adjusting the output power of each power device according to the power adjustment amount of each power device to control the power supply frequency of the grid side within a preset frequency range; Wherein, before obtaining the power supply frequencies of the power supply side of the power supply system at each moment between the current moment and the initial moment, the method further includes: Determining the time range of each adjustment stage according to the initial moment and the stage duration of a preset plurality of adjustment stages; the plurality of adjustment stages include a frequency modulation stage, a power compensation stage, and a voltage recovery stage; Determining the adjustment stage to which the current moment belongs according to the current moment and the time range of each adjustment stage; If the adjustment stage to which the current moment belongs is the frequency modulation stage, the obtaining the power supply frequencies of the power supply side of the power supply system at each moment between the current moment and the initial moment includes: Obtaining the first power supply frequency change amount of the grid side of the power supply system at each moment between the current moment and the initial moment and the voltage-frequency droop coefficient of the converter station on the grid side of the power supply system; Determining the change amount of the DC bus voltage of the power supply system according to each first power supply frequency change amount and the voltage-frequency droop coefficient; Determining the second power supply frequency change amount of the power supply side at each moment between the current moment and the initial moment according to the change amount of the DC bus voltage and the frequency-voltage droop coefficient of the converter station on the power supply side; Determining the power supply frequencies of the power supply side at each moment between the current moment and the initial moment according to each second power supply frequency change amount and the initial power supply frequency of the power supply side at the initial moment.

2. The method according to claim 1, wherein The determining the power adjustment amount of each power device according to each power supply frequency and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs includes: Calculating the frequency change rate between the current moment and the initial moment according to each power supply frequency; Determining the power adjustment amount of each power device based on the droop control strategy, the inertia response strategy, the second power supply frequency change amount, the frequency change rate, and the inertia control coefficients corresponding to each power device; the inertia control coefficients include a droop coefficient and an inertia response coefficient.

3. The method according to claim 2, wherein If the adjustment stage to which the current moment belongs is the power compensation stage or the voltage recovery stage, the obtaining the power supply frequencies of the power supply side of the power supply system at each moment between the current moment and the initial moment includes: Sending a power supply frequency acquisition instruction to a frequency detection device, where the frequency detection device is a device in the power supply system for collecting the power supply frequencies of the power supply side at each moment between the current moment and the initial moment; Receive the power supply frequencies of the power supply side at each moment between the current moment and the initial moment sent by the frequency detection device.

4. The method according to claim 3, characterized in that If the adjustment stage to which the current moment belongs is the power compensation stage, then determining the power adjustment amount of each of the power devices according to each of the power supply frequencies and the target power distribution strategy corresponding to the adjustment stage to which the current moment belongs includes: Obtain the minimum frequency of the frequency modulation stage from each of the power supply frequencies; Determine the fixed power compensation time of the power compensation stage according to the minimum frequency and a preset time-frequency coefficient; Determine the total power value that each of the power devices needs to adjust according to the fixed power compensation time; Determine the power adjustment amount of each of the power devices according to the total power value.

5. The method according to claim 4, wherein The multiple devices include a wind turbine, an electrolyzer, and a fuel cell; determining the total power value that the multiple power devices need to adjust according to the fixed power compensation time includes: If the current moment is greater than or equal to a first preset moment and less than or equal to a second preset moment, then determine the preset fixed compensation power as the total power value that the multiple power devices need to adjust; the first preset moment is the starting moment of the power compensation stage, and the difference between the second preset moment and the first preset moment is the fixed power compensation time; If the current moment is greater than the second preset moment and less than or equal to a third preset moment, determine the total power values that the wind turbine, the electrolyzer, and the fuel cell need to adjust through the functional relationship among the current moment, the second preset moment, the third preset moment, the fixed compensation power, and the total power value; the third preset moment is the ending moment of the power compensation stage; the second preset moment is less than the third preset moment; the functional relationship is constructed according to the characteristics of the wind turbine in the power compensation stage.

6. The method according to claim 5, wherein Determining the power adjustment amount of each of the power devices according to the total power value includes: Obtain the remaining capacity of the electrolyzer and the remaining capacity of the fuel cell; If the sum of the remaining capacity of the electrolyzer and the remaining capacity of the fuel cell is greater than or equal to the fixed compensation power, then determine the power adjustment amounts of the electrolyzer and the fuel cell according to the remaining capacity of the electrolyzer, the remaining capacity of the fuel cell, and the total power value, and determine the power adjustment amount of the wind turbine to be 0; If the sum of the remaining capacity of the electrolyzer and the remaining capacity of the fuel cell is less than the fixed compensation power, then determine the power adjustment amount of the electrolyzer according to the remaining capacity of the electrolyzer, the fixed compensation power, and the total power value; determine the power adjustment amount of the fuel cell according to the remaining capacity of the fuel cell, the fixed compensation power, and the total power value; and determine the power adjustment amount of the wind turbine according to the total power value, the power adjustment amount of the electrolyzer, and the power adjustment amount of the fuel cell.

7. The method according to claim 3, wherein If the adjustment stage to which the current moment belongs is the voltage recovery stage; then determining the power adjustment amount of each power device according to the target power distribution strategy corresponding to each power supply frequency and the adjustment stage to which the current moment belongs includes: Obtaining the power supply frequency at a third preset moment, and calculating a third power supply frequency change amount of the power supply side from the third preset moment to the initial moment according to the power supply frequency at the third preset moment; the third preset moment is the end moment of the power compensation stage; Determining a voltage offset amount of the DC bus from the third preset moment to the initial moment according to the third power supply frequency change amount and the frequency-voltage droop coefficient; Determining the total power value that each power device needs to adjust according to the slope of the DC bus voltage recovery and the voltage offset amount; Determining the adjustment amount of each power device according to the total power value.

8. The method according to claim 7, characterized in that The determining the total power value that each power device needs to adjust according to the slope of the DC bus voltage recovery and the voltage offset amount includes: Determining the duration of the voltage recovery of the power supply side according to the slope of the DC bus voltage recovery and the voltage offset amount; Determining the total power consumption value that each power device needs to adjust during the voltage recovery process in the power supply system according to the rated capacitance of the DC bus, the slope, and the voltage of the DC bus at the third preset moment; Determining the total power value that each power device needs to adjust according to the total power consumption value and the duration of the voltage recovery.

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