Wind power system frequency modulation control method, device, equipment and medium

Abstract

This invention discloses a frequency regulation control method for wind power systems, relating to the field of new energy control technology. It addresses the problem of existing wind power systems' inability to adaptively adjust at different stages. The method includes the following steps: collecting and calculating wind power system data; determining the current stage based on the grid frequency; when the wind power system is in a frequency stable stage, adjusting the droop coefficient of the wind power system to zero; when the wind power system enters a frequency support stage, calculating the droop coefficient value of the wind power system based on the wind turbine speed; and when the wind power system enters a frequency recovery stage, calculating the droop coefficient value of the wind power system based on a time scale. This invention also discloses a frequency regulation control device, electronic equipment, and computer storage medium for wind power systems. By dynamically adjusting the droop coefficient, this invention improves the poor adaptability caused by setting the frequency regulation time in traditional methods.

Description

Technical Field

[0001] This invention relates to the field of new energy control technology, and in particular to a frequency regulation control method, device, equipment and medium for wind power systems that takes into account continuous frequency drops. Background Technology

[0002] As the penetration rate of new energy wind power generation increases, the increased proportion of wind power resources leads to a decrease in system inertia. Therefore, the kinetic energy stored in wind turbines is widely used to maintain the stability of the system frequency. However, when wind turbines use rotor kinetic energy for frequency support, the turbine speed decreases. When the system frequency recovers, the turbine needs to exit frequency support and return to maximum power point tracking (MPPT). When the turbine exits frequency regulation, its output power needs to be reduced to allow the speed to recover. At this time, the sudden drop in active power will cause a secondary drop in system frequency, sometimes even more severe than the primary frequency drop.

[0003] To address this, existing technologies have begun using droop control for system frequency control. Droop control adds a power reference value to the maximum power reference value, so to allow the wind turbine to return to the maximum power point after frequency support, it is only necessary to reduce the droop loop reference value to zero. However, the common method in existing technologies is to slowly and smoothly reduce it to zero over time. This method requires setting the frequency adjustment time, making it difficult for the droop coefficient to adaptively adjust with the frequency adjustment phase, thus limiting the actual control effect of flexible exit. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, one of the objectives of this invention is to provide a frequency regulation control method for wind power systems, which achieves adaptive adjustment by setting droop coefficients for wind power system frequency regulation at different stages.

[0005] One of the objectives of this invention is achieved through the following technical solution:

[0006] A frequency regulation control method for a wind power system includes the following steps:

[0007] Collect and calculate the wind turbine speed, grid frequency deviation, and the first and second derivatives of the grid frequency with respect to time at the current sampling moment of the wind power system;

[0008] Based on the first-order derivative of the grid frequency with respect to time at the current sampling time and the previous sampling time, the current stage of the wind power system is determined:

[0009] If the absolute value of the product and the difference between the first-order derivative values ​​at the current sampling time and the previous sampling time is less than the first positive threshold, the wind power system is considered to be in a frequency stable phase, and the droop coefficient of the wind power system is adjusted to zero.

[0010] If the product of the first derivative value at the current sampling time and the previous sampling time is greater than the second positive threshold and the difference is less than the third negative threshold, the wind power system is considered to have entered the frequency support stage, and the droop coefficient value of the wind power system is calculated based on the wind turbine speed value.

[0011] If the product of the first derivative value at the current sampling time and the previous sampling time is less than the fourth positive threshold and the difference is greater than the fifth positive threshold, the wind power system is considered to have entered the frequency recovery stage. The droop coefficient value of the wind power system is calculated based on the wind turbine speed value at the current time, the grid frequency difference, the second derivative value of the grid frequency with respect to time, and the time scale.

[0012] Furthermore, the system collects and calculates the wind turbine speed, grid frequency deviation, and the first and second derivatives of the grid frequency with respect to time at the current sampling moment, including:

[0013] Collect the wind turbine speed ω at the current sampling time of the wind power system. r The sample includes the power grid frequency value f and the power grid frequency reference value f at the current sampling time. N The difference is calculated to determine the grid frequency deviation Δf at the current sampling time of the wind power system;

[0014] Calculate the first-order derivative (df / dt) of the grid frequency of the wind power system at the current moment with respect to time. k And based on the first-order differential value at the current moment, further calculate the second-order differential value with respect to time (d). 2 f / dt 2 ) k .

[0015] Furthermore, an assessment of the current stage of the wind power system is conducted, including:

[0016] Determine the first-order derivative (df / dt) of the grid frequency with respect to time at the current sampling moment of the wind power system. k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) If the first derivative of the power grid frequency with respect to time at the current sampling moment is (df / dt) k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) The absolute values ​​of the product and the difference are both less than the first positive threshold (df / dt). lim_1 If so, the wind power system is considered to have entered a frequency stabilization phase;

[0017] Determine the first-order derivative (df / dt) of the grid frequency with respect to time at the current sampling moment of the wind power system. k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) If the first derivative of the power grid frequency with respect to time at the current sampling moment is (df / dt) k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) The product of is greater than the second positive threshold (df / dt). lim_2 And the difference is less than the third negative threshold (df / dt). lim_3 If so, the wind power system is considered to have entered the frequency support phase;

[0018] Determine the first-order derivative (df / dt) of the grid frequency with respect to time at the current sampling moment of the wind power system. k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) If the first derivative of the power grid frequency with respect to time at the current sampling moment is (df / dt) k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) The product of is less than the fourth positive threshold (df / dt). lim_4 And the difference is greater than the fifth positive threshold (df / dt). lim_5 If the wind power system enters the frequency recovery phase, then the wind power system is considered to have entered the frequency recovery phase.

[0019] Furthermore, the wind power system is considered to be in a frequency stable phase. When it first enters the stable phase, the droop coefficient of the wind power system is adjusted to zero; otherwise, no droop coefficient transformation is performed.

[0020] Furthermore, assuming the wind power system has entered the frequency support phase, the droop coefficient value of the wind power system is calculated based on the wind turbine speed value, including:

[0021] Establish the drop value 'a' of the wind turbine speed value and the lower limit threshold 'b' of the wind turbine speed value for the wind power system, where a = ω MPPT -ω r b = k min ×ω MPPT ω MPPT k is the rotational speed of the wind turbine in the wind power system operating in maximum power point tracking mode. min The threshold coefficient is 0. <k min <1; Establish a safety threshold c for the wind turbine speed of the wind power system, satisfying c = k safe ×(ω MPPT-b), where k safe The safety threshold coefficient is 0. <k safe <1; Establish the safe threshold value Δf for the grid frequency deviation of the wind power system. safe ;

[0022] If the degree of drop (a) in the wind turbine speed value of the wind power system is less than or equal to the safety threshold (c) of the wind turbine speed value, then the droop coefficient (K) of the wind power system is determined. D The maximum value K D_max ;

[0023] If the wind power system is determined to have a wind turbine speed drop value 'a' greater than the wind turbine speed value safety threshold 'c', and the grid frequency deviation value 'Δf' at the current sampling time of the wind power system is greater than or equal to the grid frequency deviation value safety threshold 'Δf', then the wind power system is considered to have a wind turbine speed drop value 'a' greater than or equal to the wind power system grid frequency deviation value safety threshold 'Δf'. safe Then the droop coefficient value K of the wind power system D Let be a function that monotonically decreases as time t increases, and satisfies:

[0024] When a = c, K D The maximum value K is set. D _ max When a = ω MPPT When -b, K D It is zero; when c <a<(ω MPPT When -b), the droop coefficient value K of the wind power system is... D The decreasing trend gradually decreases as time t increases;

[0025] If the drop in wind turbine speed value 'a' is greater than the safety threshold 'c' for the wind turbine speed value, and the grid frequency deviation 'Δf' at the current sampling time of the wind power system is less than the safety threshold 'Δf' for the grid frequency deviation value of the wind power system, then the wind power system is considered to be in a wind power system with the following characteristics: safe Then the droop coefficient value K of the wind power system D Let be a function that monotonically decreases as time t increases, and satisfies:

[0026] When a = c, K D The maximum value K is set. D _ max When a = ω MPPT When -b, K D It is zero; when c <a<(ω MPPT When -b), the droop coefficient value K of the wind power system is... D The decreasing trend gradually increases as time t increases;

[0027] Determine whether the wind power system is entering the frequency recovery phase for the first time. If it is entering the frequency recovery phase for the first time, set the droop coefficient value K of the wind power system. D It gradually decreases over time.

[0028] Furthermore, when the wind turbine system first enters the frequency recovery phase, the droop coefficient value gradually decreases over time; when the wind turbine system enters the frequency recovery phase for the second time, the droop coefficient value of the wind power system is calculated based on the current wind turbine speed value, the grid frequency difference, the second derivative value of the grid frequency with respect to time, and the time scale.

[0029] Furthermore, when the wind turbine system first enters the frequency recovery phase, the droop coefficient value gradually decreases over time; when the wind turbine system enters the frequency recovery phase for the second time, the droop coefficient value of the wind power system is calculated based on the current wind turbine speed, the grid frequency difference, the second derivative of the grid frequency with respect to time, and according to the time scale, including:

[0030] Determine whether the wind power system has entered the frequency support phase for the second time. If it has, then determine the wind turbine speed value ω. r Calculate the droop coefficient K of the wind power system. D ;

[0031] Establish the drop value 'a' of the wind turbine speed value and the lower limit threshold 'b' of the wind turbine speed value for the wind power system, where a = ω MPPT -ω r b = k min ×ω MPPT In the formula, ω MPPT k is the rotational speed of the wind turbine in the wind power system operating in maximum power point tracking mode. min The threshold coefficient is 0. <k min <1; Establish a safety threshold c for the wind turbine speed of the wind power system, satisfying c = k safe ×(ω MPPT -b), where k safe The safety threshold coefficient is 0. <k safe <1; Establish the safe threshold value Δf for the grid frequency deviation of the wind power system. safe ;

[0032] If the degree of drop (a) in the wind turbine speed value of the wind power system is less than or equal to the safety threshold (c) of the wind turbine speed value, then the droop coefficient (K) of the wind power system is determined. D The maximum value K is set. D _ max ;

[0033] If the wind power system is determined to have a wind turbine speed drop value 'a' greater than the wind turbine speed value safety threshold 'c', and the grid frequency deviation value 'Δf' at the current sampling time of the wind power system is greater than or equal to the grid frequency deviation value safety threshold 'Δf', then the wind power system is considered to have a wind turbine speed drop value 'a' greater than or equal to the wind power system grid frequency deviation value safety threshold 'Δf'. safe Then the droop coefficient value K of the wind power system D Let be a function that monotonically decreases as time t increases, and satisfies:

[0034] When a = c, K D The maximum value K is set. D _ max When a = ω MPPT When -b, K D It is zero; when c <a<(ω MPPT When -b), the droop coefficient value K of the wind power system is... D The decreasing trend gradually decreases as time t increases;

[0035] If the drop in wind turbine speed value 'a' is greater than the safety threshold 'c' for the wind turbine speed value, and the grid frequency deviation 'Δf' at the current sampling time of the wind power system is less than the safety threshold 'Δf' for the grid frequency deviation value of the wind power system, then the wind power system is considered to be in a wind power system with the following characteristics: safe Then the droop coefficient value K of the wind power system D (ωr) is a function that monotonically decreases as time t increases, and satisfies:

[0036] When a = c, K D The maximum value K is set. D _ max When a = ω MPPT When -b, K D It is zero; when c <a<(ω MPPT When -b), the droop coefficient value K of the wind power system is... D The decreasing trend gradually increases as time t increases;

[0037] Determine whether the wind power system has entered the frequency recovery phase for the second time. If it has entered the frequency recovery phase for the second time, then determine the wind turbine speed ω at the current moment. r The power grid frequency difference Δf and the second-order differential of the power grid frequency with respect to time (d) 2 f / dt 2 ) k To calculate the droop coefficient value K of the wind power system D Record the time point t0 when the wind power system enters the frequency recovery phase for the second time, and set the time scale Δt;

[0038] Record the current time point t, and determine the droop coefficient K of the wind power system when t = t0 + Δt. D Is it zero? If K D If the value is not zero, then set the droop coefficient value K of the wind power system. D It gradually decreases over time until it reaches zero.

[0039] The second objective of this invention is to provide a frequency regulation control device for a wind power system.

[0040] The second objective of this invention is achieved by the following technical solution:

[0041] A frequency regulation control device for a wind power system, comprising:

[0042] The data acquisition module is used to collect and calculate the wind turbine speed, grid frequency deviation, and the first and second derivative values ​​of the grid frequency with respect to time at the current sampling moment of the wind power system.

[0043] The judgment module is used to determine the current stage of the wind power system based on the first-order derivative of the grid frequency with respect to time at the current sampling time and the previous sampling time.

[0044] The adjustment and recovery module determines the wind power system's frequency stability phase if the absolute value of the product and difference of the first-order derivative values ​​at the current and previous sampling times is less than a first positive threshold, and adjusts the droop coefficient of the wind power system to zero. If the product of the first-order derivative values ​​at the current and previous sampling times is greater than a second positive threshold and the difference is less than a third negative threshold, the wind power system is considered to have entered a frequency support phase, and the droop coefficient of the wind power system is calculated based on the wind turbine speed value. If the product of the first-order derivative values ​​at the current and previous sampling times is less than a fourth positive threshold and the difference is greater than a fifth positive threshold, the wind power system is considered to have entered a frequency recovery phase, and the droop coefficient of the wind power system is calculated based on the current wind turbine speed value, the grid frequency difference, the second-order derivative of the grid frequency with respect to time, and the time scale.

[0045] A third objective of this invention is to provide an electronic device for performing one of the objectives of the invention, comprising a processor, a storage medium, and a computer program, wherein the computer program is stored in the storage medium and, when executed by the processor, implements the aforementioned wind power system frequency regulation control method.

[0046] A fourth objective of this invention is to provide a computer-readable storage medium storing one of the objectives of the invention, wherein a computer program is stored thereon, and when the computer program is executed by a processor, it implements the above-described wind power system frequency regulation control method.

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0048] This invention employs a wind power system frequency regulation exit control method that considers continuous frequency drops. It determines the wind power system's state by using wind turbine speed, grid frequency deviation, and grid frequency. The method then adjusts the droop coefficient in real time for different wind power systems under varying conditions, adapting to different frequency stages. This overcomes the potential adverse effects of secondary grid frequency drops, solves the problem of poor adaptability caused by setting frequency regulation time, and addresses the limitation of difficulty in adaptively adjusting the droop coefficient with frequency regulation stages. This achieves adaptive adjustment of the wind power system and improves the proactive frequency support effect for wind power grid connection. Attached Figure Description

[0049] Figure 1 This is a flowchart of the frequency regulation control method for a wind power system in Example 1;

[0050] Figure 2 This is a flowchart of the droop coefficient adjustment for the frequency regulation control method of the wind power system in Example 1;

[0051] Figure 3 This is a schematic diagram of the simulation results of the product and difference between the first derivative of the power grid frequency with respect to time at the current sampling moment and the first derivative of the power grid frequency with respect to time at the previous sampling moment in Example 1.

[0052] Figure 4 This is a schematic diagram of the simulation results of the grid frequency deviation value and the droop coefficient value of the virtual inertia response of the wind power system at the current sampling time during the continuous frequency drop process of Example 1, based on the time point to determine the wind power system entering different frequency stages.

[0053] Figure 5 This is a schematic diagram of the simulation results of the grid frequency deviation value and the droop coefficient value of the virtual inertia response of the wind power system at the current sampling time during the continuous frequency drop process of the wind power system in Example 1.

[0054] Figure 6 This is a structural block diagram of the wind power system frequency regulation control device in Embodiment 2;

[0055] Figure 7 This is a structural block diagram of the electronic device in Embodiment 3. Detailed Implementation

[0056] The present invention will now be described in more detail with reference to the accompanying drawings. It should be noted that the following description of the present invention with reference to the accompanying drawings is merely illustrative and not restrictive. Various embodiments can be combined with each other to form other embodiments not shown in the following description.

[0057] Example 1

[0058] Example 1 provides a frequency regulation control method for a wind power system, which aims to improve the frequency active support for wind power grid connection by adaptively adjusting the droop coefficient.

[0059] To ensure that the wind turbine's output power returns to its optimal mode after participating in primary frequency regulation control, and to prevent a secondary drop in system frequency, the droop coefficient of the wind power system needs to be gradually reduced until it reaches zero. Existing technologies often employ control strategies that reduce the droop coefficient over time, allowing the wind turbine to return to its maximum power point and minimizing the secondary drop in system frequency.

[0060] To ensure the safe operation of wind turbine speeds and the upper limit of the frequency deviation threshold, this embodiment proposes a method for adjusting the virtual inertia response droop coefficient of the wind power system based on a safety threshold coefficient and the grid frequency deviation safety threshold of the wind power system. This achieves maximum active power output while ensuring safe wind turbine speeds, thereby improving the frequency support capability of the wind power system.

[0061] Once the wind turbine enters the frequency support phase, the droop coefficient is only related to the turbine speed. This method ensures that the wind power system releases more kinetic energy in the initial stage of frequency fluctuations to raise the system's minimum frequency. At the same time, the droop coefficient decreases as the real-time speed decreases, effectively preventing excessive deceleration of the wind turbine and ensuring stable operation.

[0062] After the wind turbine enters the frequency recovery phase, the droop coefficient of the wind turbine is related to the frequency drop depth and the frequency recovery trend. The droop coefficient can be adjusted by taking into account multiple indicators and constraints to avoid secondary frequency drops in the recovery process of the system under the continuous frequency drop fault scenario.

[0063] Based on the above principles, please refer to Figure 1 As shown, a frequency regulation control method for a wind power system includes the following steps:

[0064] S1. Collect and calculate the wind turbine speed, grid frequency deviation, and the first and second derivative values ​​of the grid frequency with respect to time at the current sampling time of the wind power system;

[0065] S1 specifically includes:

[0066] Collect the wind turbine speed ω at the current sampling time of the wind power system. r The sample includes the power grid frequency value f and the power grid frequency reference value f at the current sampling time. N The difference is calculated to determine the grid frequency deviation Δf at the current sampling time of the wind power system;

[0067] Calculate the first-order derivative (df / dt) of the grid frequency of the wind power system at the current moment with respect to time. kAnd based on the first-order differential value at the current moment, further calculate the second-order differential value with respect to time (d). 2 f / dt 2 ) k .

[0068] S2. Based on the first-order derivative of the grid frequency with respect to time at the current sampling time and the previous sampling time of the wind power system, determine the current stage of the wind power system:

[0069] The specific steps in the S2 phase judgment process include:

[0070] Determine the first-order derivative (df / dt) of the grid frequency with respect to time at the current sampling moment of the wind power system. k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) If the first derivative of the power grid frequency with respect to time at the current sampling moment is (df / dt) k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) The absolute values ​​of the product and the difference are both less than the first positive threshold (df / dt). lim_1 If so, the wind power system is considered to have entered a frequency stabilization phase;

[0071] Determine the first-order derivative (df / dt) of the grid frequency with respect to time at the current sampling moment of the wind power system. k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) If the first derivative of the power grid frequency with respect to time at the current sampling moment is (df / dt) k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) The product of is greater than the second positive threshold (df / dt). lim_2 And the difference is less than the third negative threshold (df / dt). lim_3 If so, the wind power system is considered to have entered the frequency support phase;

[0072] Determine the first-order derivative (df / dt) of the grid frequency with respect to time at the current sampling moment of the wind power system. k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) If the first derivative of the power grid frequency with respect to time at the current sampling moment is (df / dt) k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1)The product of is less than the fourth positive threshold (df / dt). lim_4 And the difference is greater than the fifth positive threshold (df / dt). lim_5 If the wind power system enters the frequency recovery phase, then the wind power system is considered to have entered the frequency recovery phase.

[0073] Please refer to Figure 2 As shown, and in combination Figures 3-5 The simulation results shown illustrate a flowchart of the droop coefficient adjustment method for a wind power system frequency regulation control.

[0074] Please refer to Figure 3 The simulation results shown illustrate the first-order derivative (df / dt) of the grid frequency with respect to time at the current sampling moment during a wind power system frequency regulation exit control method that considers continuous frequency drops. k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) The simulation results of the product and difference, as well as the simulation results of the grid frequency value, frequency stage flag bit, and frequency recovery stage flag bit, are used to verify the actual situation of the product and difference under the condition that the droop coefficient value of the virtual inertia response of the wind power system is constant.

[0075] Please refer to Figure 4 The simulation results shown illustrate a frequency regulation exit control method for wind power systems considering continuous frequency drops. The simulation results demonstrate the grid frequency deviation value and the droop coefficient value of the wind power system's virtual inertia response at the current sampling time during a continuous frequency drop, based on time points to determine whether the wind power system has entered different frequency stages. This is used to verify the actual situation of the droop coefficient value of the virtual inertia response based on time points and the wind power system entering different frequency stages. As can be seen from the figure, when the wind power system enters the frequency support stage, the droop coefficient value K of the wind power system's virtual inertia response is... D It is only related to the difference between the wind turbine speed and the grid frequency. Under the premise of safe operation of the wind power system, it ensures that the wind turbine decelerates and releases a large amount of active power to achieve active frequency support. When the frequency of the wind power system drops to its lowest point, the wind power system enters the frequency recovery phase, and the droop coefficient value K of the virtual inertia response of the wind power system is... D As the frequency difference in the power grid gradually decreases and converges to zero, the wind turbine speed also gradually recovers. Subsequently, if the wind power system experiences a continuous frequency drop during the frequency recovery process, the system can identify the frequency drop and adaptively adjust the droop coefficient value for the frequency support and recovery phases, ensuring that the system achieves primary frequency regulation control and ultimately restores the wind turbine speed to its initial value.

[0076] S21. If the absolute value of the product and the difference between the first-order derivative values ​​at the current sampling time and the previous sampling time is less than the first positive threshold, the wind power system is considered to be in a frequency stable phase, and the droop coefficient of the wind power system is adjusted to zero.

[0077] S21 specifically includes:

[0078] The wind power system is considered to be in a frequency stable phase. When it first enters the stable phase, the droop coefficient of the wind power system is adjusted to zero; otherwise, no droop coefficient transformation is performed.

[0079] S22. If the product of the first derivative value at the current sampling time and the previous sampling time is greater than the second positive threshold and the difference is less than the third negative threshold, the wind power system is considered to have entered the frequency support stage, and the droop coefficient value of the wind power system is calculated based on the wind turbine speed value.

[0080] S22 specifically includes:

[0081] Establish the drop value 'a' of the wind turbine speed value and the lower limit threshold 'b' of the wind turbine speed value for the wind power system, where a = ω MPPT -ω r b = k min ×ω MPPT ω MPPT k is the rotational speed of the wind turbine in the wind power system operating in maximum power point tracking mode. min The threshold coefficient is 0. <k min <1; Establish a safety threshold c for the wind turbine speed of the wind power system, satisfying c = k safe ×(ω MPPT -b), where k safe The safety threshold coefficient is 0. <k safe <1; Establish the safe threshold value Δf for the grid frequency deviation of the wind power system. safe ;

[0082] If the degree of drop (a) in the wind turbine speed value of the wind power system is less than or equal to the safety threshold (c) of the wind turbine speed value, then the droop coefficient (K) of the wind power system is determined. D The maximum value K D max ;

[0083] If the wind power system is determined to have a wind turbine speed drop value 'a' greater than the wind turbine speed value safety threshold 'c', and the grid frequency deviation value 'Δf' at the current sampling time of the wind power system is greater than or equal to the grid frequency deviation value safety threshold 'Δf', then the wind power system is considered to have a wind turbine speed drop value 'a' greater than or equal to the wind power system grid frequency deviation value safety threshold 'Δf'. safe Then the droop coefficient value K of the wind power system DLet be a function that monotonically decreases as time t increases, and satisfies:

[0084] When a = c, K D The maximum value K is set. D _ max When a = ω MPPT When -b, K D It is zero; when c <a<(ω MPPT When -b), the droop coefficient value K of the wind power system is... D The decreasing trend gradually decreases as time t increases;

[0085] If the drop in wind turbine speed value 'a' is greater than the safety threshold 'c' for the wind turbine speed value, and the grid frequency deviation 'Δf' at the current sampling time of the wind power system is less than the safety threshold 'Δf' for the grid frequency deviation value of the wind power system, then the wind power system is considered to be in a wind power system with the following characteristics: safe Then the droop coefficient value K of the wind power system D Let be a function that monotonically decreases as time t increases, and satisfies:

[0086] When a = c, K D The maximum value K is set. D _ max When a = ω MPPT When -b, K D It is zero; when c <a<(ω MPPT When -b), the droop coefficient value K of the wind power system is... D The decreasing trend gradually increases as time t increases;

[0087] Specifically, in the experiment, the safety threshold coefficient k was set. safe =0.4, the safe threshold value Δf for the grid frequency deviation of the wind power system. safe =0.4, then the droop coefficient value K of the virtual inertia response of the wind power system in the simulation is 0.4. D Set as:

[0088]

[0089] Determine whether the wind power system is entering the frequency recovery phase for the first time. If it is entering the frequency recovery phase for the first time, set the droop coefficient value K of the wind power system. D It gradually decreases over time.

[0090] S23. If the product of the first derivative value at the current sampling time and the previous sampling time is less than the fourth positive threshold and the difference is greater than the fifth positive threshold, the wind power system is considered to have entered the frequency recovery stage. The droop coefficient value of the wind power system is calculated based on the wind turbine speed value at the current time, the grid frequency difference, the second derivative value of the grid frequency with respect to time, and the time scale.

[0091] In S23, when the wind turbine system first enters the frequency recovery phase, the sag coefficient value gradually decreases over time.

[0092] When the wind turbine system enters the frequency recovery phase for the second time, the droop coefficient of the wind power system is calculated based on the current wind turbine speed value, the grid frequency difference, the second derivative of the grid frequency with respect to time, and the time scale.

[0093] Specifically, including:

[0094] Determine whether the wind power system has entered the frequency support phase for the second time. If it has, then determine the wind turbine speed value ω. r Calculate the droop coefficient K of the wind power system. D ;

[0095] Establish the drop value 'a' of the wind turbine speed value and the lower limit threshold 'b' of the wind turbine speed value for the wind power system, where a = ω MPPT -ω r b = k min ×ω MPPT In the formula, ω MPPT k is the rotational speed of the wind turbine in the wind power system operating in maximum power point tracking mode. min The threshold coefficient is 0. <k min <1; Establish a safety threshold c for the wind turbine speed of the wind power system, satisfying c = k safe ×(ω MPPT -b), where k safe The safety threshold coefficient is 0. <k safe <1; Establish the safe threshold value Δf for the grid frequency deviation of the wind power system. safe ;

[0096] If the degree of drop (a) in the wind turbine speed value of the wind power system is less than or equal to the safety threshold (c) of the wind turbine speed value, then the droop coefficient (K) of the wind power system is determined. D The maximum value K is set. D _ max ;

[0097] If the wind power system is determined to have a wind turbine speed drop value 'a' greater than the wind turbine speed value safety threshold 'c', and the grid frequency deviation value 'Δf' at the current sampling time of the wind power system is greater than or equal to the grid frequency deviation value safety threshold 'Δf', then the wind power system is considered to have a wind turbine speed drop value 'a' greater than or equal to the wind power system grid frequency deviation value safety threshold 'Δf'. safe Then the droop coefficient value K of the wind power system D Let be a function that monotonically decreases as time t increases, and satisfies:

[0098] When a = c, K D The maximum value K is set. D _ max When a = ω MPPT When -b, K D It is zero; when c <a<(ω MPPT When -b), the droop coefficient value K of the wind power system is... D The decreasing trend gradually decreases as time t increases;

[0099] If the drop in wind turbine speed value 'a' is greater than the safety threshold 'c' for the wind turbine speed value, and the grid frequency deviation 'Δf' at the current sampling time of the wind power system is less than the safety threshold 'Δf' for the grid frequency deviation value of the wind power system, then the wind power system is considered to be in a wind power system with the following characteristics: safe Then the droop coefficient value K of the wind power system D Let be a function that monotonically decreases as time t increases, and satisfies:

[0100] When a = c, K D The maximum value K is set. D _ max When a = ω MPPT When -b, K D It is zero; when c <a<(ω MPPT When -b), the droop coefficient value K of the wind power system is... D The decreasing trend gradually increases as time t increases;

[0101] Determine whether the wind power system has entered the frequency recovery phase for the second time. If it has entered the frequency recovery phase for the second time, then determine the wind turbine speed ω at the current moment. r The power grid frequency difference Δf and the second-order differential of the power grid frequency with respect to time (d) 2 f / dt 2 ) k To calculate the droop coefficient value K of the wind power system D Record the time point t0 when the wind power system enters the frequency recovery phase for the second time, and set the time scale Δt;

[0102] Record the current time point t, and determine the droop coefficient K of the wind power system when t = t0 + Δt. D Is it zero? If K D If the value is not zero, then set the droop coefficient value K of the wind power system. D It gradually decreases over time until it reaches zero.

[0103] Please refer to Figure 5 The simulation results show the grid frequency deviation value and the droop coefficient value of the virtual inertia response of the wind power system at the current sampling time during the continuous frequency drop process of a wind power system frequency regulation exit control method considering continuous frequency drop.

[0104] Please refer to Figure 5 As shown, it illustrates the simulation results of a wind power system frequency regulation exit control method considering continuous frequency drops, including the grid frequency deviation value of the wind power system at the current sampling time during the continuous frequency drop process, and the droop coefficient value of the virtual inertia response of the wind power system.

[0105] Specifically, in the simulation, in order to simultaneously consider the droop coefficient value K of the virtual inertia response of the wind power system... D The trend of the grid frequency deviation value at the current sampling time of the wind power system and the second derivative value of the grid frequency with respect to time (d) 2 f / dt 2 ) k The convergence rate of the curve is adaptively adjusted by a proportional value. In the simulation, the droop coefficient value of the virtual inertia response of the wind power system is set as follows:

[0106]

[0107] Example 2

[0108] Example 5 discloses a device corresponding to the wind power system frequency regulation control method of the above embodiments. It is a virtual device structure of the above embodiments. Please refer to [link / reference]. Figure 6 As shown, it includes:

[0109] The acquisition module 310 is used to acquire and calculate the wind turbine speed value, grid frequency deviation value, first-order derivative value and second-order derivative value of grid frequency with respect to time at the current sampling time of the wind power system;

[0110] The judgment module 320 is used to judge the current stage of the wind power system based on the first derivative of the grid frequency with respect to time at the current sampling time and the previous sampling time.

[0111] The adjustment and recovery module 330 determines the wind power system's frequency stability phase if the absolute value of the product and difference of the first-order derivative values ​​at the current and previous sampling times is less than a first positive threshold, and adjusts the droop coefficient of the wind power system to zero. If the product of the first-order derivative values ​​at the current and previous sampling times is greater than a second positive threshold and the difference is less than a third negative threshold, the wind power system is considered to have entered a frequency support phase, and the droop coefficient of the wind power system is calculated based on the wind turbine speed value. If the product of the first-order derivative values ​​at the current and previous sampling times is less than a fourth positive threshold and the difference is greater than a fifth positive threshold, the wind power system is considered to have entered a frequency recovery phase, and the droop coefficient of the wind power system is calculated based on the current wind turbine speed value, the grid frequency difference, the second-order derivative of the grid frequency with respect to time, and the time scale.

[0112] Example 3

[0113] Figure 7 This is a schematic diagram of the structure of an electronic device provided in Embodiment 3 of the present invention, as shown below. Figure 7 As shown, the electronic device includes a processor 410, a memory 420, an input device 430, and an output device 440; the number of processors 410 in the computer device can be one or more. Figure 7 Taking a processor 410 as an example; the processor 410, memory 420, input device 430, and output device 440 in the electronic device can be connected via a bus or other means. Figure 7 Taking the example of a connection between China and Israel via a bus.

[0114] The memory 420, as a computer-readable storage medium, can be used to store software programs, computer-executable programs, and modules, such as the program instructions / modules corresponding to the wind power system frequency regulation control method in this embodiment of the invention. The processor 410 executes various functional applications and data processing of the electronic device by running the software programs, instructions, and modules stored in the memory 420, thereby implementing the wind power system frequency regulation control method of Embodiment 1 described above.

[0115] The memory 420 may primarily include a program storage area and a data storage area. The program storage area may store the operating system and at least one application program required for a given function; the data storage area may store data created based on terminal usage. Furthermore, the memory 420 may include high-speed random access memory and non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some instances, the memory 420 may further include memory remotely located relative to the processor 410, which can be connected to the electronic device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0116] Input device 430 can be used to receive input user identity information, wind power system data, time data, etc. Output device 440 may include display devices such as a display screen.

[0117] Example 4

[0118] Embodiment 7 of the present invention also provides a storage medium containing computer-executable instructions, which can be used by a computer to execute a frequency regulation control method for a wind power system, the method comprising:

[0119] Collect and calculate the wind turbine speed, grid frequency deviation, and the first and second derivatives of the grid frequency with respect to time at the current sampling moment of the wind power system;

[0120] Based on the first-order derivative of the grid frequency with respect to time at the current sampling time and the previous sampling time, the current stage of the wind power system is determined:

[0121] If the absolute value of the product and the difference between the first-order derivative values ​​at the current sampling time and the previous sampling time is less than the first positive threshold, the wind power system is considered to be in a frequency stable phase, and the droop coefficient of the wind power system is adjusted to zero.

[0122] If the product of the first derivative value at the current sampling time and the previous sampling time is greater than the second positive threshold and the difference is less than the third negative threshold, the wind power system is considered to have entered the frequency support stage, and the droop coefficient value of the wind power system is calculated based on the wind turbine speed value.

[0123] If the product of the first derivative value at the current sampling time and the previous sampling time is less than the fourth positive threshold and the difference is greater than the fifth positive threshold, the wind power system is considered to have entered the frequency recovery stage. The droop coefficient value of the wind power system is calculated based on the wind turbine speed value at the current time, the grid frequency difference, the second derivative value of the grid frequency with respect to time, and the time scale.

[0124] Of course, the computer-executable instructions provided in the embodiments of the present invention are not limited to the method operations described above, but can also perform related operations in the frequency regulation control method based on wind power system provided in any embodiment of the present invention.

[0125] Based on the above description of the implementation methods, those skilled in the art can clearly understand that the present invention can be implemented using software and necessary general-purpose hardware, and of course, it can also be implemented using hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk, or optical disk, etc., including several instructions to cause an electronic device (which may be a mobile phone, personal computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0126] It is worth noting that in the embodiments of the wind power system frequency regulation control method and device described above, the various units and modules included are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of each functional unit are only for easy differentiation and are not used to limit the scope of protection of the present invention.

[0127] For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of this invention.

Claims

1. A frequency regulation control method for a wind power system, characterized in that, Includes the following steps: Collect and calculate the wind turbine speed, grid frequency deviation, and the first and second derivatives of the grid frequency with respect to time at the current sampling moment of the wind power system; Based on the first-order derivative of the grid frequency with respect to time at the current sampling time and the previous sampling time, the current stage of the wind power system is determined: If the absolute value of the product and the difference between the first-order derivative values ​​at the current sampling time and the previous sampling time is less than the first positive threshold, the wind power system is considered to be in a frequency stable phase, and the droop coefficient of the wind power system is adjusted to zero. If the product of the first derivative value at the current sampling time and the previous sampling time is greater than the second positive threshold and the difference is less than the third negative threshold, the wind power system is considered to have entered the frequency support stage, and the droop coefficient value of the wind power system is calculated based on the wind turbine speed value. If the product of the first derivative value at the current sampling time and the previous sampling time is less than the fourth positive threshold and the difference is greater than the fifth positive threshold, the wind power system is considered to have entered the frequency recovery stage. The droop coefficient value of the wind power system is calculated based on the wind turbine speed value at the current time, the grid frequency difference, the second derivative value of the grid frequency with respect to time, and the time scale.

2. The wind power system frequency regulation control method as described in claim 1, characterized in that, Collect and calculate the wind turbine speed, grid frequency deviation, and the first and second derivatives of the grid frequency with respect to time at the current sampling moment of the wind power system, including: Collect the wind turbine speed ω at the current sampling time of the wind power system. r The sample includes the power grid frequency value f and the power grid frequency reference value f at the current sampling time. N The difference is calculated to determine the grid frequency deviation Δf at the current sampling time of the wind power system; Calculate the first-order derivative (df / dt) of the grid frequency of the wind power system at the current moment with respect to time. k And based on the first-order differential value at the current moment, further calculate the second-order differential value with respect to time (d). 2 f / dt 2 ) k .

3. The wind power system frequency regulation control method as described in claim 1, characterized in that, To assess the current stage of a wind power system, including: Determine the first-order derivative (df / dt) of the grid frequency with respect to time at the current sampling moment of the wind power system. k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) If the first derivative of the power grid frequency with respect to time at the current sampling moment is (df / dt) k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) The absolute values ​​of the product and the difference are both less than the first positive threshold (df / dt). lim_1 If so, the wind power system is considered to have entered a frequency stabilization phase; Determine the first-order derivative (df / dt) of the grid frequency with respect to time at the current sampling moment of the wind power system. k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) If the first derivative of the power grid frequency with respect to time at the current sampling moment is (df / dt) k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) The product of is greater than the second positive threshold (df / dt). lim_2 And the difference is less than the third negative threshold (df / dt). lim_3 If so, the wind power system is considered to have entered the frequency support phase; Determine the first-order derivative (df / dt) of the grid frequency with respect to time at the current sampling moment of the wind power system. k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) If the first derivative of the power grid frequency with respect to time at the current sampling moment is (df / dt) k The first-order derivative of the power grid frequency with respect to time (df / dt) at the previous sampling time. (k-1) The product of is less than the fourth positive threshold (df / dt). lim_4 And the difference is greater than the fifth positive threshold (df / dt). lim_5 If the wind power system enters the frequency recovery phase, then the wind power system is considered to have entered the frequency recovery phase.

4. The wind power system frequency regulation control method as described in claim 1, characterized in that, The wind power system is considered to be in a frequency stable phase. When it first enters the stable phase, the droop coefficient of the wind power system is adjusted to zero; otherwise, no droop coefficient transformation is performed.

5. The wind power system frequency regulation control method as described in claim 1, characterized in that, Assuming the wind power system has entered the frequency support phase, the droop coefficient of the wind power system is calculated based on the wind turbine speed value, including: Establish the drop value 'a' of the wind turbine speed value and the lower limit threshold 'b' of the wind turbine speed value for the wind power system, where a = ω MPPT -ω r b = k min ×ω MPPT ω MPPT k is the rotational speed of the wind turbine in the wind power system operating in maximum power point tracking mode. min The threshold coefficient is 0. <k min <1; Establish a safety threshold c for the wind turbine speed of the wind power system, satisfying c = k safe ×(ω MPPT -b), where k safe The safety threshold coefficient is 0. <k safe <1; Establish the safe threshold value Δf for the grid frequency deviation of the wind power system. safe ; If the degree of drop (a) in the wind turbine speed value of the wind power system is less than or equal to the safety threshold (c) of the wind turbine speed value, then the droop coefficient (K) of the wind power system is determined. D The maximum value K D_max ; If the wind power system is determined to have a wind turbine speed drop value 'a' greater than the wind turbine speed value safety threshold 'c', and the grid frequency deviation value 'Δf' at the current sampling time of the wind power system is greater than or equal to the grid frequency deviation value safety threshold 'Δf', then the wind power system is considered to have a wind turbine speed drop value 'a' greater than or equal to the wind power system grid frequency deviation value safety threshold 'Δf'. safe Then the droop coefficient value K of the wind power system D Let be a function that monotonically decreases as time t increases, and satisfies: When a = c, K D The maximum value K is set. D _ max When a = ω MPPT When -b, K D It is zero; when c <a<(ω MPPT When -b), the droop coefficient value K of the wind power system is... D The decreasing trend gradually decreases as time t increases; If the drop in wind turbine speed value 'a' is greater than the safety threshold 'c' for the wind turbine speed value, and the grid frequency deviation 'Δf' at the current sampling time of the wind power system is less than the safety threshold 'Δf' for the grid frequency deviation value of the wind power system, then the wind power system is considered to be in a wind power system with the following characteristics: safe Then the droop coefficient value K of the wind power system D Let be a function that monotonically decreases as time t increases, and satisfies: When a = c, K D The maximum value K is set. D _ max When a = ω MPPT When -b, K D It is zero; when c <a<(ω MPPT When -b), the droop coefficient value K of the wind power system is... D The decreasing trend gradually increases as time t increases; Determine whether the wind power system is entering the frequency recovery phase for the first time. If it is entering the frequency recovery phase for the first time, set the droop coefficient value K of the wind power system. D It gradually decreases over time.

6. The wind power system frequency regulation control method as described in claim 1, characterized in that, When the wind turbine system first enters the frequency recovery phase, the droop coefficient value gradually decreases over time; when the wind turbine system enters the frequency recovery phase for the second time, the droop coefficient value of the wind power system is calculated based on the current wind turbine speed value, the grid frequency difference, the second derivative of the grid frequency with respect to time, and the time scale.

7. The wind power system frequency regulation control method as described in claim 6, characterized in that, When the wind turbine system first enters the frequency recovery phase, the droop coefficient value gradually decreases over time. When the wind turbine system enters the frequency recovery phase for the second time, the droop coefficient value of the wind power system is calculated based on the current wind turbine speed, the grid frequency difference, the second derivative of the grid frequency with respect to time, and according to the time scale, including: Determine whether the wind power system has entered the frequency support phase for the second time. If it has, then determine the wind turbine speed value ω. r Calculate the droop coefficient K of the wind power system. D ; Establish the drop value 'a' of the wind turbine speed value and the lower limit threshold 'b' of the wind turbine speed value for the wind power system, where a = ω MPPT -ω r b = k min ×ω MPPT In the formula, ω MPPT k is the rotational speed of the wind turbine in the wind power system operating in maximum power point tracking mode. min The threshold coefficient is 0. <k min <1; Establish a safety threshold c for the wind turbine speed of the wind power system, satisfying c = k safe ×(ω MPPT -b), where k safe The safety threshold coefficient is 0. <k safe <1; Establish the safe threshold value Δf for the grid frequency deviation of the wind power system. safe ; If the degree of drop (a) in the wind turbine speed value of the wind power system is less than or equal to the safety threshold (c) of the wind turbine speed value, then the droop coefficient (K) of the wind power system is determined. D The maximum value K is set. D _ max ; If the wind power system is determined to have a wind turbine speed drop value 'a' greater than the wind turbine speed value safety threshold 'c', and the grid frequency deviation value 'Δf' at the current sampling time of the wind power system is greater than or equal to the grid frequency deviation value safety threshold 'Δf', then the wind power system is considered to have a wind turbine speed drop value 'a' greater than or equal to the wind power system grid frequency deviation value safety threshold 'Δf'. safe Then the droop coefficient value K of the wind power system D Let be a function that monotonically decreases as time t increases, and satisfies: When a = c, K D The maximum value K is set. D _ max When a = ω MPPT When -b, K D It is zero; when c <a<(ω MPPT When -b), the droop coefficient value K of the wind power system is... D The decreasing trend gradually decreases as time t increases; If the drop in wind turbine speed value 'a' is greater than the safety threshold 'c' for the wind turbine speed value, and the grid frequency deviation 'Δf' at the current sampling time of the wind power system is less than the safety threshold 'Δf' for the grid frequency deviation value of the wind power system, then the wind power system is considered to be in a wind power system with the following characteristics: safe Then the droop coefficient value K of the wind power system D Let be a function that monotonically decreases as time t increases, and satisfies: When a = c, K D The maximum value K is set. D _ max When a = ω MPPT When -b, K D It is zero; when c <a<(ω MPPT When -b), the droop coefficient value K of the wind power system is... D The decreasing trend gradually increases as time t increases; Determine whether the wind power system has entered the frequency recovery phase for the second time. If it has entered the frequency recovery phase for the second time, then determine the wind turbine speed ω at the current moment. r The grid frequency difference Δf and the second-order differential of the grid frequency with respect to time (d²f / dt²) are given. k To calculate the droop coefficient value K of the wind power system D Record the time point t0 when the wind power system enters the frequency recovery phase for the second time, and set the time scale Δt; Record the current time point t, and determine the droop coefficient K of the wind power system when t = t0 + Δt. D Is it zero? If K D If the value is not zero, then set the droop coefficient value K of the wind power system. D It gradually decreases over time until it reaches zero.

8. A frequency regulation control device for a wind power system, characterized in that, It includes: The data acquisition module is used to collect and calculate the wind turbine speed, grid frequency deviation, and the first and second derivative values ​​of the grid frequency with respect to time at the current sampling moment of the wind power system. The judgment module is used to determine the current stage of the wind power system based on the first-order derivative of the grid frequency with respect to time at the current sampling time and the previous sampling time. The adjustment and recovery module determines the wind power system's frequency stability phase if the absolute value of the product and difference of the first-order derivative values ​​at the current and previous sampling times is less than a first positive threshold, and adjusts the droop coefficient of the wind power system to zero. If the product of the first-order derivative values ​​at the current and previous sampling times is greater than a second positive threshold and the difference is less than a third negative threshold, the wind power system is considered to have entered a frequency support phase, and the droop coefficient of the wind power system is calculated based on the wind turbine speed value. If the product of the first-order derivative values ​​at the current and previous sampling times is less than a fourth positive threshold and the difference is greater than a fifth positive threshold, the wind power system is considered to have entered a frequency recovery phase, and the droop coefficient of the wind power system is calculated based on the current wind turbine speed value, the grid frequency difference, the second-order derivative of the grid frequency with respect to time, and the time scale.

9. An electronic device comprising a processor, a storage medium, and a computer program, wherein the computer program is stored in the storage medium, characterized in that, When the computer program is executed by the processor, it implements the wind power system frequency regulation control method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the wind power system frequency regulation control method according to any one of claims 1 to 7.

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