Grid-connected wind storage frequency modulation control method based on rotor kinetic energy and energy storage soc optimization

Abstract

The application provides a grid-connected wind storage frequency modulation control method based on rotor kinetic energy and energy storage SOC optimization, which controls the wind turbine to operate in a reduced power reserve frequency control (PRFC) mode during wind storage combined frequency modulation; acquires an actual system angular frequency and a disturbance amount of the wind turbine unit, and obtains wind turbine output power according to the actual system angular frequency and the disturbance amount; obtains a system angular frequency change amount according to the actual system angular frequency and a rated angular frequency of the grid-connected wind turbine; obtains a wind turbine frequency modulation output power change amount according to the system angular frequency change amount and a frequency modulation coefficient, and the frequency modulation coefficient is used for dynamically adjusting the frequency modulation capacity of the grid-connected wind turbine; and obtains an output reference power according to the wind turbine output power and the wind turbine frequency modulation output power change amount, so as to perform frequency modulation according to the output reference power. The wind turbine dynamically adjusts the system stability according to its own dynamic characteristics during frequency modulation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind power generation control, and in particular to a grid-connected wind storage frequency modulation control method based on rotor kinetic energy and energy storage SOC optimization. BACKGROUND

[0002] The grid-connected wind power is a new type of wind power technology. Compared with the traditional grid-connected wind turbine, it can actively perceive the power grid disturbance, has controllable damping capability, and can provide active support capability of frequency and voltage for high proportion wind power grid system.

[0003] Among them, the grid-connected wind power system mainly adopts two types of control strategies of rotor kinetic energy frequency modulation and power reserve frequency control (PRFC). The former relies on adjusting the speed of the wind turbine to release or absorb kinetic energy to achieve fast frequency response; the latter reserves part of the power by deviating from the maximum power point operation, which is used as frequency modulation margin when the frequency fluctuates. However, the frequency modulation response only depends on the wind turbine itself still has deficiencies in power regulation rate and stability, especially in the case of large disturbance and variable power grid, it is difficult to achieve efficient support.

[0004] Therefore, the wind storage combined frequency modulation control has become a key way for the grid-connected wind power system to improve the frequency modulation capability. However, the wind storage combined frequency modulation control in the prior art does not fully consider the influence of the change of the working condition of the wind power system and the change of the state of the energy storage on the frequency modulation, thereby affecting the stability of the wind storage combined frequency modulation. SUMMARY

[0005] The present application provides a grid-connected wind storage frequency modulation control method based on rotor kinetic energy and energy storage SOC optimization to solve the technical problems mentioned in the background art.

[0006] In a first aspect, the present application provides a grid-connected wind storage frequency modulation control method based on rotor kinetic energy and energy storage SOC optimization, comprising:

[0007] When the grid frequency difference is greater than or equal to the frequency modulation dead zone frequency difference, control the grid-connected wind turbine to perform wind storage combined frequency modulation, and control the wind turbine to operate in the power reserve frequency control (PRFC) mode during the wind storage combined frequency modulation;

[0008] Obtain the actual system angular frequency and disturbance of the wind turbine unit, and obtain the output power of the wind turbine according to the actual system angular frequency and the disturbance;

[0009] Obtain the system angular frequency change amount according to the actual system angular frequency and the rated angular frequency of the grid-connected wind turbine;

[0010] Obtain the wind turbine frequency modulation output power change amount according to the system angular frequency change amount and the frequency modulation coefficient, and the frequency modulation coefficient is used to dynamically adjust the frequency modulation capability of the grid-connected wind turbine;

[0011] According to the wind turbine output power and the wind turbine frequency modulation output power variation, an output reference power is obtained to perform frequency modulation according to the output reference power.

[0012] Optionally, before the wind turbine frequency modulation output power variation is obtained according to the system angular frequency variation and the frequency modulation coefficient, the method further comprises:

[0013] obtaining a maximum rotor speed variation, a minimum rotor speed variation, a rotor speed deviation of the wind turbine currently participating in the frequency modulation process, a minimum limit frequency modulation power, and a maximum limit frequency modulation power;

[0014] obtaining a ratio of a current adjustable kinetic energy of the wind turbine to a maximum adjustable kinetic energy of the wind turbine according to the maximum rotor speed variation, the minimum rotor speed variation, the rotor speed deviation of the wind turbine currently participating in the frequency modulation process, and the grid frequency difference;

[0015] obtaining a ratio of a current variable output power of the wind turbine to a maximum variable output power of the wind turbine according to the minimum limit frequency modulation power, the maximum limit frequency modulation power, and the grid frequency difference;

[0016] obtaining the frequency modulation coefficient according to the ratio of the current adjustable kinetic energy of the wind turbine to the maximum adjustable kinetic energy of the wind turbine and the ratio of the current variable output power of the wind turbine to the maximum variable output power of the wind turbine.

[0017] Optionally, the frequency modulation coefficient is obtained according to the ratio of the current adjustable kinetic energy of the wind turbine to the maximum adjustable kinetic energy of the wind turbine and the ratio of the current variable output power of the wind turbine to the maximum variable output power of the wind turbine, comprising:

[0018] determining a smaller value of the ratio of the current adjustable kinetic energy of the wind turbine to the maximum adjustable kinetic energy of the wind turbine and the ratio of the current variable output power of the wind turbine to the maximum variable output power of the wind turbine;

[0019] obtaining the frequency modulation coefficient based on a Sigmoid function according to the smaller value of the ratio of the current adjustable kinetic energy of the wind turbine to the maximum adjustable kinetic energy of the wind turbine and the ratio of the current variable output power of the wind turbine to the maximum variable output power of the wind turbine.

[0020] Optionally, the wind turbine output power is obtained according to the actual system angular frequency and the disturbance, comprising:

[0021] obtaining an initial wind turbine output power according to the actual system angular frequency and the disturbance;

[0022] obtaining the wind turbine output power according to the initial wind turbine output power and a limit frequency modulation power.

[0023] Optionally, the method further comprises:

[0024] obtaining the charge-discharge power of the energy storage system corresponding to the grid-connected wind turbine at the current time, the current available charge-discharge capacity of the energy storage, the initial value of the energy storage system power and the energy storage SOC;

[0025] obtaining the current value of the energy storage SOC corresponding to the current time according to the current available charge-discharge capacity of the energy storage and the energy storage system power;

[0026] obtaining the predicted value of the energy storage SOC corresponding to the next time according to the charge-discharge power corresponding to the current time, the current value of the energy storage SOC and the initial value of the energy storage SOC;

[0027] obtaining the energy storage output compensation power corresponding to the current time according to the predicted value of the energy storage SOC and the current available charge-discharge capacity of the energy storage;

[0028] obtaining the compensation coefficient corresponding to the current time according to the current value of the energy storage SOC based on the characteristics of the inverse tangent function;

[0029] obtaining the target energy storage output compensation power corresponding to the current time according to the energy storage output compensation power, the compensation coefficient corresponding to the current time and the maximum available capacity of the energy storage;

[0030] correcting the charge-discharge power at the current time according to the target energy storage output compensation power corresponding to the current time, to obtain the corrected charge-discharge power.

[0031] Optionally, the obtaining of the charge-discharge power corresponding to the current time comprises:

[0032] obtaining the droop coefficient corresponding to the current time according to the current value of the energy storage SOC, the initial value of the energy storage SOC and the grid frequency difference;

[0033] obtaining the energy storage output reference power corresponding to the current time according to the droop coefficient corresponding to the current time and the grid frequency difference;

[0034] obtaining the charge-discharge power corresponding to the current time according to the energy storage output reference power corresponding to the current time.

[0035] In a second aspect, the application provides a grid-connected wind storage frequency modulation control device based on rotor kinetic energy and energy storage SOC optimization, comprising:

[0036] a mode switching module, configured to control the grid-connected wind turbine to perform wind storage joint frequency modulation when the grid frequency difference is greater than or equal to the frequency difference of the frequency modulation dead zone, and control the wind turbine to operate in the power reduction power reserve frequency control (PRFC) mode during the wind storage joint frequency modulation;

[0037] an obtaining module, configured to obtain an actual system angular frequency and a disturbance of the fan unit, and obtain a wind turbine output power according to the actual system angular frequency and the disturbance;

[0038] a rotor primary frequency modulation module, configured to obtain a system angular frequency variation according to the actual system angular frequency and a rated angular frequency of a grid-connected wind turbine, and obtain a wind turbine frequency modulation output power variation according to the system angular frequency variation and a frequency modulation coefficient, the frequency modulation coefficient being used to dynamically adjust a frequency modulation capability of the grid-connected wind turbine;

[0039] a frequency modulation output module, configured to obtain an output reference power according to the wind turbine output power and the wind turbine frequency modulation output power variation, so as to perform frequency modulation according to the output reference power.

[0040] Optionally, the obtaining module obtains the wind turbine output power according to the actual system angular frequency and the disturbance, and specifically is configured to:

[0041] obtain an initial wind turbine output power according to the actual system angular frequency and the disturbance;

[0042] obtain the wind turbine output power according to the initial wind turbine output power and a limit frequency modulation power.

[0043] Optionally, before the rotor primary frequency modulation module obtains the wind turbine frequency modulation output power variation according to the system angular frequency variation and the frequency modulation coefficient, the rotor primary frequency modulation module is further configured to:

[0044] obtain a maximum rotor speed variation, a minimum rotor speed variation, a rotor speed deviation of the grid-connected wind turbine in a current frequency modulation process, a minimum limit frequency modulation power, and a maximum limit frequency modulation power;

[0045] obtain a proportion of a current adjustable kinetic energy of the wind turbine relative to a maximum adjustable kinetic energy of the wind turbine according to the maximum rotor speed variation, the minimum rotor speed variation, the rotor speed deviation of the grid-connected wind turbine in the current frequency modulation process, and the grid frequency difference;

[0046] obtain a proportion of a current variable output power of the wind turbine relative to a maximum variable output power of the wind turbine according to the minimum limit frequency modulation power, the maximum limit frequency modulation power, and the grid frequency difference;

[0047] obtain the frequency modulation coefficient according to the proportion of the current adjustable kinetic energy of the wind turbine relative to the maximum adjustable kinetic energy of the wind turbine and the proportion of the current variable output power of the wind turbine relative to the maximum variable output power of the wind turbine.

[0048] Optionally, the rotor primary frequency modulation module obtains the frequency modulation coefficient according to a proportion of current adjustable kinetic energy of the fan relative to maximum adjustable kinetic energy thereof and a proportion of current variable output power of the fan relative to maximum variable output power thereof, and is specifically used for:

[0049] determining a smaller value of the proportion of current adjustable kinetic energy of the fan relative to maximum adjustable kinetic energy thereof and the proportion of current variable output power of the fan relative to maximum variable output power thereof;

[0050] obtaining the frequency modulation coefficient based on a Sigmoid function according to the smaller value of the proportion of current adjustable kinetic energy of the fan relative to maximum adjustable kinetic energy thereof and the proportion of current variable output power of the fan relative to maximum variable output power thereof.

[0051] Optionally, the energy storage frequency modulation module is used for:

[0052] obtaining, at a current time, charge-discharge power of an energy storage system corresponding to the grid-connected fan, currently available charge-discharge capacity of the energy storage, energy storage system power and an initial value of an energy storage state of charge (SOC);

[0053] obtaining a current value of the energy storage SOC corresponding to the current time according to the currently available charge-discharge capacity of the energy storage and the energy storage system power;

[0054] obtaining a predicted value of the energy storage SOC corresponding to a next time according to the charge-discharge power corresponding to the current time, the current value of the energy storage SOC and the initial value of the energy storage SOC;

[0055] obtaining an energy storage output compensation power corresponding to the current time according to the predicted value of the energy storage SOC and the currently available charge-discharge capacity of the energy storage;

[0056] obtaining a compensation coefficient corresponding to the current time according to the current value of the energy storage SOC based on an inverse tangent function characteristic;

[0057] obtaining a target energy storage output compensation power corresponding to the current time according to the energy storage output compensation power, the compensation coefficient corresponding to the current time and a maximum available capacity of the energy storage;

[0058] correcting the charge-discharge power at the current time according to the target energy storage output compensation power corresponding to the current time to obtain a corrected charge-discharge power.

[0059] Optionally, the energy storage frequency modulation module obtains the charge-discharge power corresponding to the current time, and is specifically used for:

[0060] obtaining a droop coefficient corresponding to the current time according to the current value of the energy storage SOC, the initial value of the energy storage SOC and the grid frequency difference;

[0061] obtaining, according to the droop coefficient corresponding to the current moment and the power grid frequency difference, the energy storage output reference power corresponding to the current moment;

[0062] obtaining, according to the energy storage output reference power corresponding to the current moment, the charge-discharge power corresponding to the current moment.

[0063] In a third aspect, the present application provides an electronic device, comprising: a processor and a memory;

[0064] The memory stores computer execution instructions.

[0065] The processor executes the computer execution instructions stored in the memory, so that the processor executes the method of any one of the first aspect.

[0066] In a fourth aspect, the embodiments of the present application provide a readable storage medium, comprising a program or instructions, when the program or instructions are run on a computer, the method of any one of the above first aspect is executed.

[0067] In a fifth aspect, the embodiments of the present application provide a computer program product, comprising a computer program, when the computer program is executed by a processor, the method of any one of the first aspect is realized.

[0068] The method for grid-connected wind storage frequency modulation control based on rotor kinetic energy and energy storage SOC optimization provided by the present application obtains the power grid frequency difference, and judges whether the power grid frequency difference is greater than or equal to the frequency modulation dead zone frequency difference; when the power grid frequency difference is greater than or equal to the frequency modulation dead zone frequency difference, the wind turbine unit is controlled to run in the reduced load power standby frequency modulation PRFC mode; the actual system angular frequency and the disturbance of the wind turbine unit are obtained, and the wind turbine output power is obtained according to the actual system angular frequency and the disturbance; the speed difference value is obtained according to the actual system angular frequency and the rated speed of the wind turbine unit; the additional electromagnetic power increment is obtained according to the speed difference value and the frequency modulation coefficient, and the frequency modulation coefficient is used to adjust the frequency modulation capacity of the wind turbine unit; the output reference power is obtained according to the wind turbine output power and the electromagnetic power increment, so as to modulate according to the output reference power. In this embodiment, when the rotor kinetic energy is modulated during the grid-connected wind storage combined frequency modulation control, the frequency modulation coefficient is introduced, the purpose of adjusting the frequency modulation capacity of the wind turbine through the frequency modulation coefficient is realized, so that the secondary fluctuation of the frequency during the speed recovery can be reduced as much as possible. BRIEF DESCRIPTION OF DRAWINGS

[0069] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0070] Figure 1 The flow chart of the grid-connected type wind storage frequency modulation control method based on rotor kinetic energy and energy storage SOC optimization provided by an embodiment of the present application is shown in FIG. 6;

[0071] Figure 2 The structural schematic diagram of the wind turbine unit rotating speed regulation control block diagram provided by an embodiment of the present application is shown in FIG. 7;

[0072] Figure 3 The relationship diagram of virtual inertia and frequency deviation and voltage fluctuation provided by an embodiment of the present application is shown in FIG. 8;

[0073] Figure 4 The flow chart of the energy storage SOC charge and discharge limit and recovery frequency modulation control method provided by an embodiment of the present application is shown in FIG. 9;

[0074] Figure 5 The block diagram of the energy storage SOC charge and discharge limit and recovery frequency modulation control method provided by an embodiment of the present application is shown in FIG. 10;

[0075] Figure 6 The simulation diagram of the grid-connected type wind storage frequency modulation control method based on rotor kinetic energy and energy storage SOC optimization provided by an embodiment of the present application is shown in FIG. 11; k add Root locus of variation;

[0076] Figure 7 The simulation diagram of the grid-connected type wind storage frequency modulation control method based on rotor kinetic energy and energy storage SOC optimization provided by an embodiment of the present application is shown in FIG. 11;

[0077] Figure 8 The comparison diagram of the frequency response of the grid-connected type wind storage frequency modulation control method based on rotor kinetic energy and energy storage SOC optimization and the existing method provided by an embodiment of the present application is shown in FIG. 12;

[0078] Figure 9 The comparison diagram of the wind power output of the grid-connected type wind storage frequency modulation control method based on rotor kinetic energy and energy storage SOC optimization and the existing method provided by an embodiment of the present application is shown in FIG. 13;

[0079] Figure 10 The comparison diagram of the energy storage output power of the grid-connected type wind storage frequency modulation control method based on rotor kinetic energy and energy storage SOC optimization and the existing method provided by an embodiment of the present application is shown in FIG. 14;

[0080] Figure 11 The comparison diagram of the wind turbine rotating speed of the grid-connected type wind storage frequency modulation control method based on rotor kinetic energy and energy storage SOC optimization and the existing method provided by an embodiment of the present application is shown in FIG. 15;

[0081] Figure 12 The comparison diagram of the energy storage SOC of the grid-connected type wind storage frequency modulation control method based on rotor kinetic energy and energy storage SOC optimization and the existing method provided by an embodiment of the present application is shown in FIG. 16;

[0082] Figure 13 A structural schematic diagram of a grid-connected wind storage frequency modulation control device based on rotor kinetic energy and energy storage SOC optimization provided by an embodiment of the present application is shown in FIG. 1.

[0083] Figure 14 A structural schematic diagram of an electronic device provided by an embodiment of the present application is shown in FIG. 2. DETAILED DESCRIPTION

[0084] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0085] For grid-connected wind storage joint frequency modulation, the transfer function corresponding to system frequency modulation is:

[0086] (1)

[0087] wherein, Δ P W is the wind power increment, Δ P E is the energy storage system power increment, Δ P L is the load variation, Δ P G is the active power increment of other energy units outside the wind storage system participating in primary frequency modulation, H and D are respectively the system inertia constant and damping constant, Δ f is the grid frequency difference, Δ P is the power variation, p represents the system order, s 1 represents the Laplace operator.

[0088] wherein, the output power variation Δ P W is expressed as follows:

[0089] (2)

[0090] wherein, Δ P * ref = Δ P del + Δ P add That is, the active power reference value of the VSG control is composed of the wind turbine output power P del and the frequency modulation output power Padd composition, K vsg is a primary frequency modulation coefficient, D vsg is a virtual damping of the VSG, J vsg is a virtual inertia of the VSG, and Δω is a system angular frequency variation.

[0091] wherein the energy storage system power increment Δ P E The expression is as follows:

[0092] (3)

[0093] wherein, J bess is an equivalent rotational inertia of the super capacitor, w N is a rated angular frequency of the grid-connected wind turbine, represents a frequency variation rate, D f represents a primary frequency modulation damping coefficient (analog power-frequency response) of the super capacitor.

[0094] Below, on the basis of the grid-connected wind storage combined frequency modulation control, the technical solution of the embodiment is described.

[0095] Figure 1 is a flowchart of a grid-connected wind storage frequency modulation control method based on rotor kinetic energy and energy storage SOC optimization provided by an embodiment of the application. As Figure 1 shown, the grid-connected wind storage combined frequency modulation control method provided by the embodiment includes:

[0096] S101, obtain a power grid frequency difference, and when the power grid frequency difference is greater than or equal to a frequency modulation dead zone difference, control the grid-connected wind turbine to perform wind storage combined frequency modulation, and when the wind storage combined frequency modulation is performed, control the wind turbine unit to operate in a load reduction power reserve frequency modulation (PRFC) mode.

[0097] In this step, when the power grid frequency difference is within the frequency modulation dead zone difference, frequency modulation is not needed, which can avoid parameter settings of frequent adjustment of the wind turbine unit, reduce frequent actions of mechanical parts due to small frequency differences, thereby prolonging the service life of the equipment and improving the stability of the power grid.

[0098] When it is detected that the power grid frequency changes, the power grid frequency difference Δ f is obtained, and when the power grid frequency difference Δ f is greater than or equal to the frequency modulation dead zone difference, wind storage combined frequency modulation is performed; otherwise, frequency modulation is not performed.

[0099] wherein, for the frequency modulation performed by the wind turbine body in the wind storage combined frequency modulation, the frequency modulation is performed by the wind turbine bodyFigure 2 As shown, if the fan unit is running in the MPPT mode at this time, first control the fan unit to switch to run in the PRFC mode. Among them, Figure 2 d in the formula is the load reduction rate of the grid-connected fan.

[0100] S102, obtain the actual system angular frequency and the disturbance of the fan unit, and obtain the wind turbine output power according to the actual system angular frequency and the disturbance.

[0101] In this step, when the fan unit is running in the PRFC mode, the actual system angular frequency ω and the disturbance of the fan unit are obtained, so that the wind turbine output power is obtained according to the actual system angular frequency and the disturbance. P del .

[0102] Optionally, one specific embodiment of S102 is:

[0103] S1021, obtaining the initial wind turbine output power according to the actual system angular frequency and the disturbance.

[0104] S1022, obtaining the wind turbine output power according to the initial wind turbine output power and the limit frequency modulation power.

[0105] Specifically, the wind turbine output power cannot exceed the limit frequency modulation power, so the initial wind turbine output power and the limit frequency modulation power are compared, when the initial wind turbine output power is less than the limit frequency modulation power, the initial wind turbine output power is determined as the wind turbine output power; when the initial wind turbine output power is greater than or equal to the limit frequency modulation power, the limit frequency modulation power is determined as the wind turbine output power.

[0106] S103, obtaining the system angular frequency change amount according to the actual system angular frequency and the rated angular frequency of the grid-connected fan.

[0107] In this step, the system angular frequency change amount Δω is obtained according to the actual system angular frequency ω and the rated angular frequency of the grid-connected fan ω N .

[0108] S104, obtaining the wind turbine frequency modulation output power change amount according to the system angular frequency change amount and the frequency modulation coefficient, the frequency modulation coefficient is used to dynamically adjust the frequency modulation capacity of the grid-connected fan.

[0109] In this step, the frequency modulation coefficient k rp is introduced into the rotor kinetic energy control to evaluate the primary frequency modulation capacity of the grid-connected fan in the PRFC mode. Among them, the frequency modulation coefficient k rp is related to the speed and the difference of the grid frequency, so the frequency modulation coefficient k rp is dynamically changed.

[0110] wherein the wind turbine frequency modulation output power variation ΔPf is obtained by the system angular frequency variation Δω and the frequency modulation coefficient k rp P add .

[0111] S105, obtaining an output reference power according to the wind turbine output power and the wind turbine frequency modulation output power variation, so as to perform frequency modulation according to the output reference power.

[0112] In this step, the output reference power of the virtual synchronous generator VSG is obtained according to the wind turbine output power P del and the wind turbine frequency modulation output power variation ΔPf P add , that is, as shown in formula (4):

[0113] (4)

[0114] The wind turbine performs frequency modulation according to the output reference power P*ref .

[0115] In this embodiment, when the grid frequency difference is greater than or equal to the frequency modulation dead zone frequency difference, the grid-connected wind turbine is controlled to perform wind storage combined frequency modulation, and when the wind storage combined frequency modulation is performed, the wind turbine is controlled to operate in the reduced load power reserve frequency control PRFC mode; the actual system angular frequency and the disturbance of the wind turbine unit are obtained, and the wind turbine output power is obtained according to the actual system angular frequency and the disturbance; the system angular frequency variation is obtained according to the actual system angular frequency and the rated angular frequency of the grid-connected wind turbine; the wind turbine frequency modulation output power variation is obtained according to the system angular frequency variation and the frequency modulation coefficient, and the frequency modulation coefficient is used to dynamically adjust the frequency modulation capability of the grid-connected wind turbine; the output reference power is obtained according to the wind turbine output power and the wind turbine frequency modulation output power variation, so as to perform frequency modulation according to the output reference power. In this embodiment, the frequency modulation coefficient is introduced in the rotor kinetic energy frequency modulation when the grid-connected wind storage combined frequency modulation control is performed. Since the frequency modulation coefficient is related to the rotational speed and the grid frequency difference, the frequency modulation parameter dynamically changes, so that the wind turbine realizes the purpose of dynamically adjusting the system stability according to its own dynamic characteristics in the frequency modulation process through the frequency modulation coefficient, so as to reduce the frequency secondary fluctuation as much as possible when the rotational speed is recovered.

[0116] Optionally, before S104, the method further comprises:

[0117] S1041, obtaining the maximum rotational speed variation, the minimum rotational speed variation, the rotor rotational speed deviation of the grid-connected wind turbine in the current frequency modulation process, and the minimum limit frequency modulation power and the maximum limit frequency modulation power. ​​

[0118] In this step, the maximum value of the change in rotational speed, the minimum value of the change in rotational speed, and the minimum value and the maximum value of the limit frequency modulation power are obtained by referring to the prior art. The rotor speed deviation of the grid-connected wind turbine currently participating in the frequency modulation process can be obtained by the following method:

[0119] The additional electromagnetic power increment of the grid-connected wind turbine participating in the frequency modulation control process based on the VSG control is as follows:

[0120] (5)

[0121] The electromagnetic power correction amount output by the additional frequency modulation control module of the grid-connected wind turbine is:

[0122] (6)

[0123] Wherein, H WTG is the inertia time constant of the wind turbine, ω r0 is the initial value of the rotor speed, k del is the load shedding rate, and the rotor speed deviation expression of the wind turbine currently participating in the frequency modulation process is obtained according to formula (5) and formula (6):

[0124] (7)

[0125] S1042, according to the maximum value of the change in rotational speed, the minimum value of the change in rotational speed, the rotor speed deviation of the grid-connected wind turbine currently participating in the frequency modulation process, and the grid frequency difference, the ratio of the current adjustable kinetic energy of the wind turbine unit to the maximum adjustable kinetic energy is obtained.

[0126] In this step, the ratio of the current adjustable kinetic energy of the wind turbine unit to the maximum adjustable kinetic energy is obtained according to formula (8) k r :

[0127] (8)

[0128] Wherein, Δ ω rmin , Δ ω rmax are the maximum value and the minimum value of the change in rotational speed, respectively, and Δ ω r is the rotor speed deviation of the grid-connected wind turbine currently participating in the frequency modulation process.

[0129] S1043, according to the minimum value and the maximum value of the limit frequency modulation power, and the grid frequency difference, the ratio of the current variable output power of the wind turbine to the maximum variable output power is obtained.

[0130] In this step, the ratio of the current variable output power of the fan to the maximum variable output power of the fan is obtained according to formula (9) k p :

[0131] (9)

[0132] wherein, Δ P max , Δ P min are the unit values of the minimum and maximum limit frequency modulation power respectively.

[0133] S1044, according to the ratio of the current adjustable kinetic energy of the fan to the maximum adjustable kinetic energy of the fan and the ratio of the current variable output power of the fan to the maximum variable output power of the fan, obtain the frequency modulation coefficient.

[0134] In this step, the ratio of the current adjustable kinetic energy of the fan to the maximum adjustable kinetic energy of the fan k r and the ratio of the current variable output power of the fan to the maximum variable output power of the fan k p may be selected to calculate the frequency modulation coefficient.

[0135] Specifically, S1044 includes the following steps:

[0136] Step 1, determine the smaller value of the ratio of the current adjustable kinetic energy of the fan to the maximum adjustable kinetic energy of the fan and the ratio of the current variable output power of the fan to the maximum variable output power of the fan.

[0137] Specifically, according to the definition of k r and k p , when the grid frequency decreases, k r increases with the increase of wind speed, k p decreases with the increase of wind speed; when the grid frequency rises, the trend of the two is opposite. Therefore, the frequency modulation capacity of the grid-connected wind turbine should depend on the smaller value of the two, that is, f =min[ kr , k p ].

[0138] Step 2, according to the smaller value of the ratio of the current adjustable kinetic energy of the fan to the maximum adjustable kinetic energy of the fan and the ratio of the current variable output power of the fan to the maximum variable output power of the fan, obtain the frequency modulation coefficient based on the Sigmoid function.

[0139] Specifically, according to f =min[kr , k p The frequency modulation coefficient is determined based on the Sigmoid function. k rp That is, according to formula (10) k rp :

[0140] (10)

[0141] in, k rp It should vary with the power grid frequency deviation Δ f The parameters gradually approach 1 from 0 to fully utilize the frequency regulation capability of the wind turbine. a The rate of change must be controlled; too small or too large a rate is detrimental to system stability. Parameter b determines the initial degree of the fan's participation in frequency regulation; too large or too small a rate limits the frequency regulation effect. Both factors need to be considered in relation to the frequency regulation coefficient. k rp To assess the impact, we selected a=0.217 and b=2.536.

[0142] In this embodiment, by setting the frequency regulation coefficient, the frequency regulation coefficient is dynamically changed according to the grid frequency deviation, so that the rotor kinetic energy state can adaptively adjust the power, optimize the kinetic energy release process, suppress the secondary frequency drop caused by the rapid decrease in speed, thereby improving the sustainability of frequency regulation and wind energy utilization efficiency.

[0143] Furthermore, in the joint frequency regulation control of wind and energy storage in a grid-connected system, based on the improvement of the system's frequency support capability through rotor kinetic energy optimization strategies for grid-connected wind turbines, this application introduces supercapacitors as fast power support units to address the dual requirements of high dynamic frequency fluctuation response of the system and sustainable operation of energy storage SOC. This constructs a multi-timescale frequency regulation system that is synergistic and complementary between wind and energy storage. By establishing a variable coefficient feedback control strategy that considers the charging and discharging limits and SOC recovery characteristics of energy storage, dynamic adaptive adjustment of energy storage power is achieved, thereby further optimizing frequency regulation performance and improving the stability and reliability of the power grid.

[0144] The relationship between the energy storage power command and the actual output can be described by a first-order inertial element, whose transfer function model is as follows:

[0145] (11)

[0146] in, T bess Let be the response time constant of the energy storage. s is the integration constant.

[0147] Under constant current charging and discharging mode, the terminal voltage of the supercapacitor changes continuously, and its charging and discharging power can be expressed as the first differential form of the voltage Uc:

[0148] (12)

[0149] wherein, U c is the voltage, P cha and P dis are the charging power and the discharging power, respectively.

[0150] By referring to the swing equation of the traditional synchronous generator, the virtual inertia control of the super capacitor is expressed as:

[0151] (13)

[0152] wherein, S N is the rated capacity of the synchronous generator, and Δ P is the power variation. Wherein, Δ P and Δ f are in a positive correlation.

[0153] The synchronous generator adjusts the active power through the rotor kinetic energy, and the super capacitor adjusts through the charging and discharging, and the power equations of the two are similar. The super capacitor can be regarded as an energy storage element with virtual inertia, wherein the right part of formula (13) is equivalent to Δ P By combining formula (12) and formula (13), formula (14) is obtained:

[0154] (14)

[0155] According to formula (14), the equivalent rotational inertia constant of the super capacitor J bess is determined by multiple factors, including the system frequency, the capacitance value, and the voltage across the capacitor, etc. These factors interact with each other and significantly affect the energy storage and release characteristics of the super capacitor under different working conditions.

[0156] wherein, as shown in FIG. 2, the equivalent rotational inertia constant of the super capacitor Figure 3 is shown when the capacitance value is 10 F. J bess The three-dimensional curve of the equivalent rotational inertia constant of the super capacitor J bess can be set by adjusting the capacitance value.

[0157] Figure 4 is a flowchart of the frequency adjustment control method for the energy storage SOC charging and discharging limit and recovery provided by an embodiment of the present application. Figure 5 is a block diagram of the frequency adjustment control method for the energy storage SOC charging and discharging limit and recovery provided by an embodiment of the present application. As shown in FIG. 3, the frequency adjustment control method for the energy storage SOC charging and discharging limit and recovery provided by an embodiment of the present application comprises the following steps.Figure 4 The method comprises:

[0158] S401, obtaining the charge and discharge power of the energy storage system corresponding to the network-constructed wind turbine at the current moment, the currently available charge and discharge capacity of the energy storage, the initial value of the energy storage system power and the energy storage SOC.

[0159] In this step, the energy storage system participates in frequency modulation when the network-constructed wind storage joint frequency modulation is performed. The energy storage SOC charge and discharge limit and the energy storage SOC recovery characteristic of the energy storage system play an important role in grid frequency modulation. Therefore, in this embodiment, a power feedback control link of the energy storage SOC charge and discharge limit is added to optimize power distribution, improve frequency modulation stability, sustainability and energy storage operation safety.

[0160] Therefore, the charge and discharge power of the energy storage system at the current moment is obtained , and the currently available charge and discharge capacity of the energy storage, the initial value of the energy storage system power and the energy storage SOC.

[0161] The charge and discharge power of the energy storage system at the current moment may be obtained in the following manner:

[0162] S4011, obtaining the droop coefficient corresponding to the current moment according to the current value of the energy storage SOC, the initial value of the energy storage SOC and the grid frequency difference.

[0163] Specifically, the droop coefficient corresponding to the current moment is obtained according to formula (15) :

[0164] (15)

[0165] wherein, ξ is a power index constant.

[0166] S4012, obtaining the energy storage output reference power corresponding to the current moment according to the droop coefficient corresponding to the current moment and the grid frequency difference.

[0167] Specifically, the energy storage output reference power corresponding to the current moment is obtained according to formula (16) :

[0168] (16)

[0169] S4013, obtaining the charge and discharge power corresponding to the current moment according to the energy storage output reference power corresponding to the current moment.

[0170] Specifically, the charge and discharge power corresponding to the current moment is obtained according to formula (11) and the energy storage output reference power corresponding to the current moment : ​

[0171] (17)

[0172] Therefore, in the embodiment, the dynamic power regulation of the energy storage is based on the SOC state, the frequency response is optimized by combining the variable droop coefficient regulation and the charge and discharge limit feedback control, and the SOC adaptive adjustment mechanism is constructed, so that the energy storage droop coefficient is dynamically adjusted according to the SOC, the discharge frequency regulation capability is enhanced when the SOC is high, and the discharge is inhibited when the SOC is low to prevent over-discharge from affecting the service life.

[0173] S402, obtaining the current SOC value corresponding to the current time according to the current available charge and discharge capacity of the energy storage and the energy storage system power.

[0174] In this step, the current SOC value corresponding to the current time is obtained according to formula (18):

[0175] (18)

[0176] wherein, E bess the current available charge and discharge capacity of the energy storage, P bess the energy storage system power, and s is an integral constant, t denotes the current time

[0177] S403, obtaining the predicted SOC value of the energy storage corresponding to the next time according to the current charge and discharge power corresponding to the current time, the current SOC value of the energy storage and the initial value of the SOC of the energy storage.

[0178] In this step, the predicted SOC value of the energy storage corresponding to the next time (t+1) is obtained according to formula (19): t

[0179] (19)

[0180] S404, obtaining the energy storage output compensation power corresponding to the current time according to the predicted SOC value of the energy storage and the current available charge and discharge capacity of the energy storage.

[0181] In this step, after obtaining the predicted SOC value of the energy storage, the current available charge and discharge capacity of the energy storage is multiplied and integrated to obtain the energy storage output compensation power corresponding to the current time.

[0182] S405, obtaining the compensation coefficient corresponding to the current time according to the current SOC value of the energy storage based on the characteristics of the inverse tangent function.

[0183] In this step, the inverse tangent function is used to construct the compensation coefficient corresponding to the current time of the energy storage SOC in view of the characteristics of the inverse tangent function approaching the extreme value. k add ​a function relationship between them, the compensation coefficient corresponding to the current moment is obtained according to formula 20 k add :

[0184] (20)

[0185] wherein, α and β is an adjustment coefficient, α the value range is (0, 1.5); β the value range is (1, 3).

[0186] wherein, as shown in Figure 6 , considering the frequency regulation control strategy of the SOC charge and discharge limit and SOC recovery of the energy storage system, the energy storage power is dynamically adjusted to respond to the system state change, thereby optimizing the frequency regulation effect and improving the stability of the power grid. Based on the characteristics of the inverse tangent function, the relationship between the battery SOC and k add is nonlinear, as k add increases, the root locus approaches the imaginary axis, and when the real part is positive, the system loses stability, as Figure 6 shown, therefore, by adjusting the value of k add , the system instability can be avoided, and the stable operation of the energy storage can be ensured.

[0187] S406, according to the energy storage output compensation power, the compensation coefficient corresponding to the current moment and the maximum capacity available to the energy storage, the target energy storage output compensation power corresponding to the current moment is obtained.

[0188] In this step, according to formula (21), the target energy storage output compensation power corresponding to the current moment is obtained :

[0189] (21)

[0190] wherein, SOC ( t +1)* E bess / s indicates the energy storage output compensation power,

[0191] wherein, indicates the maximum capacity available to the energy storage.

[0192] S407, according to the target energy storage output compensation power corresponding to the current moment, the charge and discharge power at the current moment is corrected to obtain the corrected charge and discharge power.

[0193] In this step, as shown in Figure 5 , according to the target energy storage output compensation power corresponding to the current moment The current moment charge and discharge power obtained through S4011-S4013 is corrected to obtain the corrected charge and discharge power, so as to realize dynamic power adjustment of the energy storage SOC. Wherein, Figure 5 d in the formula (1) represents the energy storage utilization hours, c represents the energy storage life, and Cn represents the energy storage capacitance constant.

[0194] In the energy storage SOC recovery process in the embodiment, SOC feedback control is added to realize dynamic adaptive adjustment of the energy storage power. Further, in the wind storage joint frequency modulation, based on the rotor kinetic energy constraint and the energy storage SOC dynamic adjustment mechanism, the frequency support process of the wind storage system under multiple time scales is coordinated. The proposed frequency response strategy fully considers the charge and discharge boundary and dynamic recovery characteristics of the energy storage system, dynamically adjusts the energy storage based on the SOC state, and optimizes the frequency modulation response by combining the variable droop coefficient adjustment and the charge and discharge limit feedback control. The energy storage SOC adaptive adjustment mechanism is constructed, so that the energy storage droop coefficient is dynamically adjusted with the energy storage SOC, the discharge modulation capacity is enhanced when the energy storage SOC is high, and the discharge is inhibited when the energy storage SOC is low to prevent over-discharge from affecting the life. At the same time, the power distribution is optimized by combining the energy storage power constraint and the energy storage SOC feedback control, the frequency modulation stability, sustainability and energy storage operation safety are improved, the energy storage power is adaptively adjusted with the grid frequency deviation and load change, and the rapid frequency response capability and operation adaptability of the system are significantly improved.

[0195] Simulation embodiment of the technical scheme of the present application:

[0196] To verify the effectiveness of the proposed joint frequency modulation control strategy of the grid-connected wind storage system based on rotor kinetic energy and energy storage SOC optimization, a simulation test system including grid-connected wind turbines, energy storage systems, synchronous generators and typical AC loads is built, and the structure is as shown in Figure 7 The wind farm is composed of 15 doubly-fed induction wind turbines with a rated capacity of 5 MW, and the rated power of the supporting energy storage system is 3 MW, and the energy storage capacity is 6 MWh.

[0197] To verify the effectiveness of the proposed strategy under variable wind speed conditions, the following three kinds of collaborative control strategies of the grid-connected wind storage system are compared and analyzed under step load disturbance conditions: ① improved droop control; ② traditional MPC control; and ③ the grid-connected wind storage frequency modulation control based on rotor kinetic energy and energy storage SOC optimization mentioned in the present application, which is recorded as EMPC control.

[0198] To verify the effectiveness of the strategy under low wind speed condition of 7 m / s, the initial SOC is set to 50%, and a step load disturbance with an amplitude of 30 MW is added at 5s. To evaluate the control effect of the frequency modulation control strategy and the maintenance effect of the energy storage SOC, in addition to the maximum frequency deviation Δfmax and the steady-state frequency deviation Δ f sIn addition to serving as an evaluation metric, the absolute value of the rate of change of SOC is added to measure the effectiveness of the control strategy.

[0199] Absolute value of the rate of change of SOC | vSOC The expression for | is:

[0200] (twenty two)

[0201] In the formula, t o , t s These are the simulation start and end times, respectively. SOC o , SOC s These represent the state of charge at the beginning and end of the energy storage frequency regulation, respectively.

[0202] Depend on Figures 8-12 It can be seen that the proposed EMPC control can dynamically adjust the wind and storage output ratio according to the system frequency change, giving full play to the advantages of wind and storage coordinated frequency regulation and improving system stability and economy. Combined with the frequency regulation indicators in Table 1, it can be seen that its maximum frequency deviation Δ f max Compared to droop control and traditional MPC control, the deviation is reduced by 16.54% and 5.43% respectively, and the steady-state frequency deviation Δ f s It also reaches the minimum, reducing costs by 7.04% compared to traditional MPC control.

[0203] Table 1 Results of frequency regulation index at low wind speeds

[0204]

[0205] Under low wind speed conditions, grid-connected wind turbines lack sufficient kinetic energy, and continuous frequency regulation at the lowest turbine speed can easily lead to turbine shutdown and system instability. The grid-connected DFIG based on EMPC control extends the duration of the speed maintained at the lowest point (0.733 pu), improving it by 0.012 pu compared to the other two methods, and also results in more stable speed changes; simultaneously, the final energy storage system... v SOC The value is 0.81, and the maximum output depth is reduced by approximately 22.64%. Therefore, by effectively ensuring the stable operation of grid-connected wind turbine units and improving energy utilization efficiency, the reliability and sustainability of wind-storage systems during frequency regulation can be enhanced.

[0206] Figure 13 This is a schematic diagram of a grid-type wind-storage frequency regulation control device based on rotor kinetic energy and energy storage SOC optimization, provided as an embodiment of this application. Figure 13As shown, the grid-forming wind storage combined frequency modulation control device comprises: a mode switching module 901, an acquisition module 902, a primary frequency modulation module 903, and a frequency modulation output module 904. Figure 13 As shown, the grid-forming wind storage combined frequency modulation control device further comprises: an energy storage frequency modulation module 905.

[0207] The mode switching module 901 is configured to control the grid-forming wind turbine to perform wind storage combined frequency modulation when the grid frequency difference is greater than or equal to the frequency difference of the frequency modulation dead zone, and control the wind turbine to operate in the power reserve frequency control (PRFC) mode during the wind storage combined frequency modulation.

[0208] The acquisition module 902 is configured to acquire an actual system angular frequency and a disturbance amount of the wind turbine unit, and obtain a wind turbine output power according to the actual system angular frequency and the disturbance amount.

[0209] The rotor primary frequency modulation module 903 is configured to obtain a system angular frequency variation according to the actual system angular frequency and a rated angular frequency of the grid-forming wind turbine, and obtain a wind turbine frequency modulation output power variation according to the system angular frequency variation and a frequency modulation coefficient, the frequency modulation coefficient being used to dynamically adjust the frequency modulation capability of the grid-forming wind turbine.

[0210] The frequency modulation output module 904 is configured to obtain an output reference power according to the wind turbine output power and the wind turbine frequency modulation output power variation, and perform frequency modulation according to the output reference power.

[0211] Optionally, the acquisition module 902 obtains the wind turbine output power according to the actual system angular frequency and the disturbance amount, and specifically is configured to:

[0212] obtain an initial wind turbine output power according to the actual system angular frequency and the disturbance amount;

[0213] obtain the wind turbine output power according to the initial wind turbine output power and a limit frequency modulation power.

[0214] Optionally, before the rotor primary frequency modulation module 903 obtains the wind turbine frequency modulation output power variation according to the system angular frequency variation and the frequency modulation coefficient, the rotor primary frequency modulation module 903 is further configured to:

[0215] obtain a maximum rotor speed variation, a minimum rotor speed variation, a rotor speed deviation of the grid-forming wind turbine in a current frequency modulation process, a minimum limit frequency modulation power, and a maximum limit frequency modulation power;

[0216] obtain a proportion of a current adjustable kinetic energy of the wind turbine relative to a maximum adjustable kinetic energy of the wind turbine according to the maximum rotor speed variation, the minimum rotor speed variation, the rotor speed deviation of the grid-forming wind turbine in the current frequency modulation process, and the grid frequency difference.

[0217] obtaining a ratio of a current variable output power of the wind turbine to a maximum variable output power of the wind turbine according to the minimum limit frequency modulation power, the maximum limit frequency modulation power and the grid frequency difference;

[0218] obtaining the frequency modulation coefficient according to the ratio of the current variable output power of the wind turbine to the maximum variable output power of the wind turbine and the ratio of the current adjustable kinetic energy of the wind turbine to the maximum adjustable kinetic energy of the wind turbine.

[0219] Optionally, the rotor primary frequency modulation module 903 obtains the frequency modulation coefficient according to the ratio of the current variable output power of the wind turbine to the maximum variable output power of the wind turbine and the ratio of the current adjustable kinetic energy of the wind turbine to the maximum adjustable kinetic energy of the wind turbine, and is specifically used for:

[0220] determining a smaller value of the ratio of the current variable output power of the wind turbine to the maximum variable output power of the wind turbine and the ratio of the current adjustable kinetic energy of the wind turbine to the maximum adjustable kinetic energy of the wind turbine;

[0221] obtaining the frequency modulation coefficient based on a Sigmoid function according to the smaller value of the ratio of the current variable output power of the wind turbine to the maximum variable output power of the wind turbine and the ratio of the current adjustable kinetic energy of the wind turbine to the maximum adjustable kinetic energy of the wind turbine.

[0222] Optionally, the energy storage frequency modulation module 905 is used for:

[0223] obtaining a charge and discharge power of an energy storage system corresponding to the grid-forming wind turbine at a current time, a currently available charge and discharge capacity of the energy storage, a power of the energy storage system and an initial value of an energy storage state of charge (SOC);

[0224] obtaining a current value of the energy storage SOC corresponding to the current time according to the currently available charge and discharge capacity of the energy storage and the power of the energy storage system;

[0225] obtaining a predicted value of the energy storage SOC corresponding to a next time according to the charge and discharge power corresponding to the current time, the current value of the energy storage SOC and the initial value of the energy storage SOC;

[0226] obtaining an energy storage output compensation power corresponding to the current time according to the predicted value of the energy storage SOC and the currently available charge and discharge capacity of the energy storage;

[0227] obtaining a compensation coefficient corresponding to the current time according to the current value of the energy storage SOC based on an inverse tangent function characteristic;

[0228] obtaining a target energy storage output compensation power corresponding to the current time according to the energy storage output compensation power, the compensation coefficient corresponding to the current time and a maximum capacity available to the energy storage;

[0229] The charge-discharge power of the current moment is corrected according to the target energy storage output compensation power corresponding to the current moment, to obtain corrected charge-discharge power.

[0230] Optionally, the energy storage frequency modulation module 905 obtains the charge-discharge power of the current moment, and is specifically used for:

[0231] According to the energy storage SOC current value, the energy storage SOC initial value and the power grid frequency difference, a droop coefficient corresponding to the current moment is obtained.

[0232] According to the droop coefficient corresponding to the current moment and the power grid frequency difference, an energy storage output reference power corresponding to the current moment is obtained.

[0233] According to the energy storage output reference power corresponding to the current moment, a charge-discharge power corresponding to the current moment is obtained.

[0234] The network-constructing wind storage frequency modulation control device based on rotor kinetic energy and energy storage SOC optimization provided by the embodiments of the present application can refer to the implementation process of the above method embodiments, and has similar implementation principles and technical effects. Therefore, the implementation process of the present embodiment will not be described here.

[0235] Figure 14 The structural schematic diagram of the electronic device provided by an embodiment of the present application is shown in FIG. 10. Figure 14 As shown in FIG. 10, the electronic device includes a processor 1010 and a memory 1020.

[0236] The memory 1020 stores computer execution instructions.

[0237] The processor 1010 executes the computer execution instructions stored in the memory 1020, so that the processor 1010 executes the method described in any of the above embodiments.

[0238] The electronic device provided by the embodiments of the present application can refer to the implementation process of the above method embodiments, and has similar implementation principles and technical effects. Therefore, the implementation process of the present embodiment will not be described here.

[0239] In the above Figure 14In the illustrated embodiment, it is to be understood that the processor can be a central processing unit (CPU), but can also be other general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), and so on. The general purpose processor can be a microprocessor or the processor can be any conventional processor. The steps of the methods disclosed in connection with the present application can be embodied directly in hardware, in software with associated processor, or in a combination of software and hardware.

[0240] The memory can include a high-speed RAM memory and can also include a non-volatile storage NVM, such as at least one disk memory.

[0241] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, and so on. The bus can be divided into an address bus, a data bus, a control bus, and so on. For ease of representation, the bus in the drawings of the present application is not limited to only one bus or one type of bus.

[0242] The embodiments of the present application also provide a computer readable storage medium, the computer readable storage medium stores computer execution instructions, when the processor executes the computer execution instructions, the method shown in the above method embodiments is implemented.

[0243] The above computer readable storage medium, the above readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general or special purpose computer.

[0244] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an application-specific integrated circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0245] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0246] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A network configuration type wind storage frequency modulation control method based on rotor kinetic energy and energy storage SOC optimization, characterized in that, The method comprises the following steps: When the grid frequency difference is greater than or equal to the frequency modulation dead zone frequency difference, the grid-connected wind turbine is controlled to perform wind storage combined frequency modulation, and when the wind storage combined frequency modulation is performed, the wind turbine is controlled to operate in a reduced load power reserve frequency control (PRFC) mode; An actual system angular frequency and a disturbance amount of the wind turbine unit are obtained, and wind turbine output power is obtained according to the actual system angular frequency and the disturbance amount; A system angular frequency variation amount is obtained according to the actual system angular frequency and a rated angular frequency of the grid-connected wind turbine; A wind turbine frequency modulation output power variation amount is obtained according to the system angular frequency variation amount and a frequency modulation coefficient, the frequency modulation coefficient being used to dynamically adjust the frequency modulation capability of the grid-connected wind turbine; An output reference power is obtained according to the wind turbine output power and the wind turbine frequency modulation output power variation amount, and frequency modulation is performed according to the output reference power; Before the wind turbine frequency modulation output power variation amount is obtained according to the system angular frequency variation amount and the frequency modulation coefficient, the following steps are further included: A maximum rotor speed variation value, a minimum rotor speed variation value, a rotor speed deviation of the grid-connected wind turbine in a current frequency modulation process, a minimum limit frequency modulation power value and a maximum limit frequency modulation power value are obtained; A ratio of a current adjustable kinetic energy of the wind turbine to a maximum adjustable kinetic energy of the wind turbine is obtained according to the maximum rotor speed variation value, the minimum rotor speed variation value, the rotor speed deviation of the grid-connected wind turbine in the current frequency modulation process and the grid frequency difference; A ratio of a current variable output power of the wind turbine to a maximum variable output power of the wind turbine is obtained according to the minimum limit frequency modulation power value, the maximum limit frequency modulation power value and the grid frequency difference; The frequency modulation coefficient is obtained according to the ratio of the current adjustable kinetic energy of the wind turbine to the maximum adjustable kinetic energy of the wind turbine and the ratio of the current variable output power of the wind turbine to the maximum variable output power of the wind turbine; The frequency modulation coefficient is obtained according to the ratio of the current adjustable kinetic energy of the wind turbine to the maximum adjustable kinetic energy of the wind turbine and the ratio of the current variable output power of the wind turbine to the maximum variable output power of the wind turbine, comprising: A smaller value of the ratio of the current adjustable kinetic energy of the wind turbine to the maximum adjustable kinetic energy of the wind turbine and the ratio of the current variable output power of the wind turbine to the maximum variable output power of the wind turbine is determined; The frequency modulation coefficient is obtained based on a Sigmoid function according to the smaller value of the ratio of the current adjustable kinetic energy of the wind turbine to the maximum adjustable kinetic energy of the wind turbine and the ratio of the current variable output power of the wind turbine to the maximum variable output power of the wind turbine; The charge and discharge power of the energy storage system corresponding to the grid-connected wind turbine at a current time, the current available charge and discharge capacity of the energy storage, the energy storage system power and the initial value of the energy storage SOC are obtained; A current value of the energy storage SOC corresponding to the current time is obtained according to the current available charge and discharge capacity of the energy storage and the energy storage system power; A predicted value of the energy storage SOC corresponding to a next time is obtained according to the charge and discharge power corresponding to the current time, the current value of the energy storage SOC and the initial value of the energy storage SOC; A compensation power of the energy storage output corresponding to the current time is obtained according to the predicted value of the energy storage SOC and the current available charge and discharge capacity of the energy storage; According to the current value of the energy storage SOC, a compensation coefficient corresponding to the current moment is obtained based on the characteristics of an inverse tangent function; According to the energy storage output compensation power, the compensation coefficient corresponding to the current moment, and the maximum capacity available to the energy storage, a target energy storage output compensation power corresponding to the current moment is obtained; According to the target energy storage output compensation power corresponding to the current moment, the charge-discharge power at the current moment is corrected to obtain corrected charge-discharge power.

2. The method of claim 1, wherein, The smaller value between the proportion of the current adjustable energy of the fan relative to the maximum adjustable energy of the fan and the proportion of the current variable output power of the fan relative to the maximum variable output power of the fan is obtained, and the frequency modulation coefficient is obtained based on a Sigmoid function, including: The smaller value between the proportion of the current adjustable energy of the fan relative to the maximum adjustable energy of the fan and the proportion of the current variable output power of the fan relative to the maximum variable output power of the fan is obtained, and the frequency modulation coefficient is obtained based on a Sigmoid function according to a target formula, wherein the target formula is: wherein, f = min[ kr , k p ], parameter a controls the rate of change, parameter b determines the initial degree of participation of the fan in the frequency regulation.

3. The method of claim 2, wherein, The value of the parameter a is 0.217, the value of the parameter b is 2.

536.

4. The method according to any one of claims 1 to 3, characterized in that, The wind turbine output power is obtained according to the actual system angular frequency and the disturbance, including: An initial wind turbine output power is obtained according to the actual system angular frequency and the disturbance; The wind turbine output power is obtained according to the initial wind turbine output power and the limit frequency modulation power.

5. The method of claim 1, wherein, The charge-discharge power corresponding to the current moment is obtained, including: According to the current value of the energy storage SOC, the initial value of the energy storage SOC, and the grid frequency difference, a droop coefficient corresponding to the current moment is obtained; According to the droop coefficient corresponding to the current moment and the grid frequency difference, an energy storage output reference power corresponding to the current moment is obtained; According to the energy storage output reference power corresponding to the current moment, a charge-discharge power corresponding to the current moment is obtained.

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