An adaptive control method and device for a wind turbine based on short-circuit ratio identification

Abstract

The application discloses a kind of short-circuit ratio identification-based wind turbine adaptive control method and device, it is related to wind turbine control field, and the extraction of disturbance response signal is obtained by double SOGI scheme, the short-circuit ratio of power grid is calculated based on this, the change trend of power grid is determined using the short-circuit ratio obtained multiple times, adaptive control coefficient is determined according to change trend, the proportion of current source type control scheme and voltage source type control scheme in wind turbine overall control is adjusted according to adaptive control coefficient, and two kinds of control scheme jointly constitute unit overall control. Disturbance response signal can be simply obtained by double SOGI scheme, which reduces the operation difficulty and cost;By adjusting adaptive control coefficient, smooth transition of two control modes can be realized, disturbance impact caused by direct switching to system is avoided to reduce system stability, and the advantages of the two control schemes can also be combined to ensure better control effect under various grid strengths.

Description

Technical Field

[0001] The present invention relates to the field of wind turbine control, and in particular to a method and device for adaptively controlling a wind turbine based on short-circuit ratio identification. Background Art

[0002] Current wind turbine control schemes are typically categorized as current source control or voltage source control. Current source control is suitable for strong grid environments, while voltage source control is suitable for weak grid environments. When the wind turbine's grid strength changes, the corresponding control scheme must be switched based on the changed grid strength. To determine the control scheme, the wind turbine's grid strength must be determined. Since the short-circuit ratio is positively correlated with grid strength, grid strength is currently typically determined based on the short-circuit ratio, based on online identification of the system's short-circuit ratio.

[0003] However, because current control schemes only include current source control and voltage source control, neither control scheme alone can effectively control the wind turbine when the wind turbine's grid strength is between strong and weak. Furthermore, when the wind turbine's grid strength changes from weak to strong or vice versa, switching between the two control schemes is necessary. The current approach typically involves directly switching from one control scheme to another. This direct switching process can introduce uncertain disturbances and shocks to the grid, thereby reducing grid stability.

[0004] Furthermore, when determining the short-circuit ratio, the grid impedance is typically calculated first to further determine the short-circuit ratio. Impedance calculations are currently divided into two methods: passive and active. The passive method extracts harmonics generated by grid distortion or uses the inherent harmonics of the inverter to calculate impedance. The active method injects disturbances into the grid connection point and then extracts the disturbance response signal to calculate impedance. However, the passive method's calculation process is easily affected by the system operating state of the wind turbine, resulting in low accuracy. The active method requires discrete Fourier transform analysis to extract the disturbance response signal, which is complex and requires high-performance equipment for calculation. High-performance equipment comes at a high cost. Summary of the Invention

[0005] The purpose of the present invention is to provide an adaptive control method and device for wind turbines based on short-circuit ratio identification, which avoids directly switching control schemes and reducing the stability of the power grid, and can also ensure better control effects on power grids under various power grid strengths.

[0006] To solve the above technical problems, the present invention provides an adaptive control method for a wind turbine generator system based on short-circuit ratio identification, comprising:

[0007] When a disturbance signal is detected to be injected into the power grid of the wind turbine generator system, a disturbance response signal at the grid connection point of the power grid is obtained by using a dual SOGI scheme;

[0008] determining the impedance of the power grid when the power grid is disturbed by the disturbance response signal;

[0009] determining the impedance of the power grid using the impedance when disturbed and the rated frequency of the power grid;

[0010] Determining the short-circuit ratio according to the grid impedance and the rated capacity and preset rated voltage at the grid connection point;

[0011] Determine a change trend of the power grid strength based on the currently obtained short-circuit ratio and the short-circuit ratios obtained N times in a row, wherein the change trend includes an increasing trend and a decreasing trend, and N is a positive integer;

[0012] Determining an adaptive control coefficient corresponding to the currently obtained short-circuit ratio according to the change trend;

[0013] Adjusting the weights of the current source control scheme and the voltage source control scheme in the wind turbine generator set in the overall control of the wind turbine generator set according to the adaptive control coefficient;

[0014] The sum of the weight of the current source control scheme in the overall control of the wind turbine generator set and the weight of the voltage source control scheme in the overall control of the wind turbine generator set is equal to 100%.

[0015] Preferably, before determining the adaptive control coefficient corresponding to the currently obtained short-circuit ratio according to the change trend, the method further includes:

[0016] Obtaining a voltage value at the grid connection point;

[0017] Determining whether the voltage value is within a preset voltage range;

[0018] If not, the overall control of the wind turbine generator set is adjusted to the complete voltage source control scheme.

[0019] Preferably, before determining the adaptive control coefficient corresponding to the currently obtained short-circuit ratio according to the change trend, the method further includes:

[0020] Obtaining a voltage change rate at the grid connection point;

[0021] Determining whether the voltage change speed is greater than a preset change speed;

[0022] If so, the overall control of the wind turbine generator set is adjusted to the complete voltage source control scheme.

[0023] Preferably, determining the adaptive control coefficient corresponding to the currently obtained short-circuit ratio according to the change trend includes:

[0024] In the change trend, determining a relationship between the short-circuit ratio corresponding to the currently obtained short-circuit ratio and an adaptive control coefficient;

[0025] The adaptive control coefficient corresponding to the currently obtained short circuit ratio is determined by using the relationship and the currently obtained short circuit ratio.

[0026] Preferably, before determining the change trend of the power grid strength according to the currently obtained short-circuit ratio and the short-circuit ratios obtained N times in a row, the method further includes:

[0027] When the short-circuit ratio is not less than a first preset short-circuit ratio, adjusting the overall control of the wind turbine generator set to the complete current source control scheme;

[0028] When the short-circuit ratio is not greater than a second preset short-circuit ratio, adjusting the overall control of the wind turbine generator set to a complete voltage source control scheme;

[0029] When the short-circuit ratio is greater than the second preset short-circuit ratio and less than the first preset short-circuit ratio, entering the step of determining a change trend of the power grid according to the currently obtained short-circuit ratio and the short-circuit ratios obtained N times in a row;

[0030] Wherein, the second preset short-circuit ratio is smaller than the first preset short-circuit ratio.

[0031] Preferably, while adjusting the weights of the current source control scheme and the voltage source control scheme in the wind turbine generator set in the overall control of the wind turbine generator set according to the adaptive control coefficient, the method further includes:

[0032] Controlling the weight of the active power droop control in the voltage source control scheme and the phase-locked loop control in the current source control scheme in the phase-locked control of the wind turbine generator system according to the adaptive control coefficient;

[0033] The weights of the reactive power-voltage droop control in the voltage source control scheme and the fixed reactive power outer loop control in the current source control scheme in the reactive power outer loop control of the wind turbine are controlled according to the adaptive control coefficient.

[0034] Preferably, determining the impedance of the power grid when it is disturbed by using the disturbance response signal includes:

[0035] The ratio between the voltage amplitude and the current amplitude of the disturbance response signal is used as the impedance of the power grid when it is disturbed.

[0036] Preferably, before obtaining the disturbance response signal at the grid connection point of the power grid using the dual SOGI solution, the method further includes:

[0037] Determining the current amplitude and disturbance frequency of the disturbance signal;

[0038] Acquiring a voltage signal and a current signal at the grid connection point;

[0039] Obtaining a disturbance response signal at a grid connection point of the power grid using a dual SOGI solution, including:

[0040] Acquiring a fundamental wave signal in the power grid using a first SOGI;

[0041] Determine the fundamental signal, determine the difference between the voltage signal and the current signal, and use the difference as a harmonic signal;

[0042] amplifying the harmonic signal by a preset multiple;

[0043] A signal at the disturbance frequency contained in the harmonic signal amplified by the preset multiple is obtained by using the second SOGI, and is used as the disturbance response signal.

[0044] Preferably, before using the dual SOGI to obtain the disturbance response signal at the grid connection point of the power grid, the method further includes:

[0045] Determining the rated current of the power grid when it is operating normally without disturbance;

[0046] determining a preset current amplitude of the disturbance signal according to the rated current;

[0047] A disturbance signal having a preset duration and a strength of the preset current amplitude is injected into the grid connection point.

[0048] The present application also provides an adaptive control device for a wind turbine generator system based on short-circuit ratio identification, comprising:

[0049] Memory for storing computer programs;

[0050] The processor is configured to implement the steps of the above-mentioned method for adaptive control of a wind turbine generator system based on short-circuit ratio identification when executing the computer program.

[0051] The present application provides an adaptive control method and device for a wind turbine based on short-circuit ratio identification. Dual SOGIs are used to extract disturbance response signals at the grid connection point and calculate the short-circuit ratio of the power grid. The short-circuit ratios obtained multiple times are used to determine the changing trend of the power grid. Based on the changing trend, an adaptive control coefficient corresponding to the currently obtained short-circuit ratio is determined. The proportion of the current source control scheme and the voltage source control scheme in the wind turbine in the overall control of the unit is adjusted based on the control coefficient. The two control schemes together constitute the overall control of the unit. By obtaining disturbance response signals through dual SOGIs, real-time and effective extraction of disturbance response signals can be achieved without changing the system structure or the original operating state. Complex calculation methods and high-performance equipment are also unnecessary to obtain disturbance response signals, resulting in minimal impact on the system and reduced operational difficulty and economic costs. When switching control schemes is required, a smooth transition between the two control modes can be achieved by adjusting the adaptive control coefficient, avoiding the disturbance impact of direct switching on the system and reducing system stability. Furthermore, the adaptive control combining the two control schemes can combine the good frequency and voltage support capabilities of the voltage source control scheme with the fast response capabilities of the current source control scheme, ensuring better control effects under various grid strengths. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the prior art and the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0053] Figure 1 A flow chart of an adaptive control method for a wind turbine generator system based on short-circuit ratio identification provided in this application;

[0054] Figure 2 A function diagram of an adaptive control coefficient provided by this application;

[0055] Figure 3 A schematic diagram of the structure of a SOGI provided in this application;

[0056] Figure 4 A schematic diagram of a SOGI Bode diagram provided in this application;

[0057] Figure 5 A schematic diagram of a process for obtaining a disturbance response signal using SOGI provided in this application;

[0058] Figure 6 A schematic diagram of the structure of an adaptive control system for a wind turbine generator system based on short-circuit ratio identification provided by this application;

[0059] Figure 7 A schematic diagram of a method of injecting a disturbance signal provided in this application;

[0060] Figure 8 A schematic diagram of direct switching of a control scheme of the prior art;

[0061] Figure 9 A control block diagram for adaptive switching of a wind turbine generator system provided in this application;

[0062] Figure 10 This is a schematic structural diagram of an adaptive control device for a wind turbine generator system based on short-circuit ratio identification provided in this application. DETAILED DESCRIPTION

[0063] The core of the present invention is to provide an adaptive control method and device for wind turbines based on short-circuit ratio identification, which avoids directly switching control schemes and reducing the stability of the power grid, and can also ensure better control effects on power grids under various power grid strengths.

[0064] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0065] Currently, there are two control schemes for wind turbines: current source control and voltage source control. Voltage source control has better adaptability to weak grids, while current source control is more suitable for strong grids. It can be seen that these two control schemes have certain "complementary" characteristics for wind turbines. These two control schemes have their own advantages and are applicable to different scenarios. Different control schemes need to be adopted according to the actual operation of the wind turbine, but currently they are usually switched directly. For example, please refer to Figure 8 , Figure 8 This is a schematic diagram of a direct switching control scheme in the prior art. When the wind turbine's grid transitions from a weak to a weak state, it directly switches from voltage source control to current source control. When the grid transitions from a weak to a weak state, it also directly switches from current source control to voltage source control. This switching method can cause significant short-term impacts on the grid, resulting in uncertain disturbances.

[0066] To solve the above technical problems, please refer to Figure 1 , Figure 1A flowchart of a method for adaptively controlling a wind turbine generator system based on short-circuit ratio identification provided in this application is applied to a processor connected to a grid connection point of a wind turbine generator system. The method for adaptively controlling a wind turbine generator system based on short-circuit ratio identification includes:

[0067] S1: When a disturbance signal is detected to be injected into the grid of the wind turbine, a dual SOGI scheme is used to obtain a disturbance response signal at the grid connection point;

[0068] S2: Determine the impedance when the power grid is disturbed through the disturbance response signal;

[0069] S3: Determine the grid impedance using the impedance at the time of disturbance and the rated frequency of the grid;

[0070] S4: Determine the short-circuit ratio based on the grid impedance, the rated capacity at the grid connection point, and the preset rated voltage;

[0071] S5: determining a change trend of the power grid strength based on the currently obtained short-circuit ratio and the short-circuit ratios obtained for the previous N consecutive times, where the change trend includes an increasing trend and a decreasing trend, and N is a positive integer;

[0072] S6: Determine the adaptive control coefficient corresponding to the current short-circuit ratio according to the change trend;

[0073] S7: adjusting the weights of the current source control scheme and the voltage source control scheme in the wind turbine generator set in the overall control of the wind turbine generator set according to the adaptive control coefficient;

[0074] The sum of the weight of the current source control scheme in the overall control of the wind turbine generator set and the weight of the voltage source control scheme in the overall control of the wind turbine generator set is equal to 100%.

[0075] Since grid strength is positively correlated with the short-circuit ratio, and the short-circuit ratio needs to be calculated based on the grid impedance, there are two methods for obtaining grid impedance: passive and active. The passive method uses the harmonics generated by grid distortion or the inherent harmonics of the grid-connected inverter to input into the grid, then extracts and calculates the grid impedance. The active method injects a certain disturbance into the grid. Since the components of the disturbance will flow through the grid side and the generator side respectively, a disturbance response will be generated at the grid connection point. The active method uses algorithms or hardware equipment to extract the corresponding disturbance response signal to calculate the impedance. Compared with the active method, the passive method's measurement process is easily affected by the operating state of the wind turbine, resulting in low accuracy of the obtained grid impedance. The active method usually uses discrete Fourier transform (DFT) analysis to extract harmonics. The analysis method is complex or requires high-performance sampling and analog-to-digital conversion equipment, which is complex to operate and has high cost.

[0076] Taking into account that the passive method is easily affected by the operating state of the wind turbine, and the accuracy of the obtained grid impedance is not high, this application is modified on the basis of the active method. After other devices inject a disturbance signal into the grid, it is first necessary to obtain the disturbance response signal at the grid connection point. Specifically, considering that the disturbance signal does not always exist, it is necessary to quickly and accurately extract the disturbance response signal from the voltage signal at the grid connection point within the time period of the disturbance signal injection. The grid connection point signal can be separated by using SOGI (Second-Order General Integrator) or other similar structures such as a double second-order generalized integrator. The processor uses SOGI to extract the disturbance response signal. Since SOGI can also realize the filtering function, the disturbance response signal obtained by the processor is more stable.

[0077] For example, see Figure 3 , Figure 3 A schematic diagram of the structure of a SOGI provided in this application, according to Figure 3 It can be seen that the transfer function of SOGI is:

[0078]

[0079] Where u is the input signal coming from the grid connection point, u` is the output signal, qu` is the signal after the phase of u` is shifted by 90°, T(s) is the transfer function of u` to u, and D(s) is the transfer function of qu` to u. ω, ω`, ε, and k are all custom control parameters, which are related to the frequency f of the input signal: ω is the angular velocity, ω` is the control angular frequency of the SOGI control link, ε is the input signal frequency error control, k is the input signal error ratio control parameter, and 1 / s is the integral link in the control. It can be seen that through SOGI, two signals u` and qu` that are identical and orthogonal to the original input signal u can be obtained. For this application, u` and u have the same phase, so u` is used as the disturbance response signal to be used later. As for qu`, since its properties are consistent with u`, qu` can also be used as the disturbance response signal. The specific parameters can be determined according to the actual application.

[0080] As a preferred embodiment, determining the impedance when the power grid is disturbed by using the disturbance response signal includes:

[0081] The ratio between the voltage amplitude and the current amplitude of the disturbance response signal is used as the impedance of the power grid when it is disturbed.

[0082] After obtaining the disturbance response signal u' at the grid connection point, the impedance value of the grid under the influence of the disturbance signal is calculated:

[0083]

[0084] Based on this, the absolute value of the impedance is determined as:

[0085]

[0086] Among them, Z(f p ) and |Z(f p )| are respectively the power grid at a frequency of f p The actual impedance value under interference and the absolute value of the impedance value, and are the voltage phasor and current phasor of the disturbance response signal u`, U pm and I pm are the voltage amplitude and current amplitude of the disturbance response signal u` respectively.

[0087] In addition, |Z(f p )|also equals Among them, R g is the equivalent resistance of the transmission system, X g is the equivalent reactance. Ideally, the equivalent resistance does not change with frequency, but the reactance is proportional to the frequency. Considering that the resistance in the high-voltage transmission line is much smaller than the reactance, and as the line grows, the reactance value increases faster than the resistance value, the resistance component can be ignored. At this time, |Z(f p )|approximately equal to|X g (f p )|, and according to the calculation formula of system reactance, |X g (f p )|equal to ω p L g ,ω p is the angular frequency of the disturbance signal, L g The equivalent inductance of the transmission system shows that in addition to calculating the impedance using the voltage and current amplitudes mentioned above, the impedance can also be calculated based on the angular frequency and inductance, and the system impedance is approximately proportional to the frequency. Therefore, the system impedance at the disturbance frequency can be converted to the rated frequency to obtain:

[0088]

[0089] Among them, Z(f n ) is the grid impedance at the rated operating frequency, f n is the rated operating frequency, f p is the frequency of the disturbance signal.

[0090] After obtaining the grid impedance, the short-circuit ratio of the grid can be calculated. Specifically, since the short-circuit ratio is equal to the ratio between the current short-circuit capacity at the grid connection point and the rated capacity; the rated capacity is fixed, and the current short-circuit capacity is equal to The product of the preset rated voltage and the short-circuit current at the grid connection point, the preset rated voltage is equal to The product of the short-circuit current at the grid connection point and the grid impedance can be used to determine the short-circuit ratio at the grid connection point according to the following formula:

[0091]

[0092] Among them, SCR is the short circuit ratio, S f is the current short-circuit capacity at the grid connection point, S n is the rated capacity at the grid connection point, U n is the rated line voltage at the grid connection point, I f is the short-circuit current at the grid connection point, Z is the above Z(f n ) is also the grid impedance at the rated operating frequency.

[0093] Considering that current wind turbines, such as distributed renewable energy generation systems, typically utilize long-distance transmission lines and multiple transformers to connect to the main grid, the system will gradually exhibit weak grid characteristics with a low short-circuit ratio. The presence of grid impedance will become a major factor affecting system stability. Grid strength is primarily measured by the short-circuit ratio (SCR). Therefore, the SCR can be used to determine grid strength and thus select the appropriate control scheme.

[0094] In order to achieve adaptive control, since the range of grid strength applicable to current source control and voltage source control is inconsistent, current source control is suitable for strong grid environment and voltage source control is suitable for weak grid environment. When the short circuit ratio changes from large to small, that is, the grid change trend is a weakening trend, it is necessary to adjust from current source control to voltage source control; when the short circuit ratio changes from small to large, that is, the grid change trend is a strengthening trend, it is necessary to adjust from voltage source control to current source control.

[0095] In the prior art, the adjustment of the control scheme is directly switched from one control scheme to another, for example, when the short-circuit ratio changes from small to large, the voltage source control is directly switched to the current source control. This method brings uncertain disturbance and impact to the system. Therefore, in the present application, a control strategy is adopted which combines the voltage source control scheme and the current source control scheme, and the adaptive control coefficient is used to realize the smooth transition of the control mode. Specifically, since the applicable range of the short-circuit ratio of the current source control and the voltage source control is different, the applicable short-circuit ratio range of the two control schemes can be determined in advance, the minimum short-circuit ratio of the optimal applicable range of the current source control scheme is taken as the maximum value of the transition region, and the maximum short-circuit ratio of the optimal applicable range of the voltage source control scheme is taken as the minimum value of the transition region. The optimal applicable range refers to the range in which the control scheme can achieve the best control effect, and the optimal applicable range is a subset of the applicable range. When the actual short-circuit ratio is within the applicable range but not within the optimal applicable range, the control scheme is still effective, but the control effect will be reduced. When the actual determined short-circuit ratio is greater than the maximum value of the transition region, only the current source control scheme is used. When the actual determined short-circuit ratio is less than the minimum value of the transition region, only the voltage source control scheme is used. When the actual determined short-circuit ratio is within the transition region, a new control strategy is formed by combining the two control schemes, and the weights of the two control schemes in the overall control of the wind turbine are determined according to the adaptive control coefficient.

[0096] Specifically, since the applicable ranges of the two control schemes are different but there is a certain intersection between them, please refer to Figure 2 , Figure 2 The function graph of the adaptive control coefficient provided in the present application is shown in the figure. The upward arrow curve is the adaptive control coefficient corresponding to each short-circuit ratio when the grid strength changes in the strengthening trend, and the downward arrow curve is the adaptive control coefficient corresponding to each short-circuit ratio when the grid strength changes in the weakening trend. When the adaptive control coefficient is equal to 1, it means that the wind turbine completely adopts the current source control scheme, and when the adaptive control coefficient is equal to 0, it means that the wind turbine completely adopts the voltage source control scheme. It can be seen that the adjustment coefficient corresponding to the same short-circuit ratio is different when the change trend is different. This is because the applicable ranges of the two control schemes have a certain intersection. When the short-circuit ratio is about to reach the applicable boundary of the control scheme being used, the adaptive control is started. This can avoid the mis-triggering of the adaptive control due to the abnormal decrease or increase of the short-circuit ratio caused by short-term unexpected situations, and can also reduce the number of switching control schemes and improve the stability of the grid.

[0097] Taking the weakening trend as an example, the applicable scope of the current source control scheme is the environment where the short-circuit ratio is greater than 3. Assuming that the original wind turbine control scheme completely adopts the current source control scheme, when the short-circuit ratio is less than 3, the impact of the short-circuit ratio continuing to decrease on the wind turbine is significantly greater than the impact of the short-circuit ratio decreasing on the wind turbine when the short-circuit ratio is greater than 3. Therefore, when the short-circuit ratio is close to 3, it is necessary to accelerate the implementation of the voltage source control scheme to maintain the stability of the wind turbine, such as Figure 2 In the process, the adaptive control coefficient begins to gradually change from 1 to 0, and the closer the short-circuit ratio is to 3, the greater the slope of the curve, and the faster the adaptive control coefficient changes with the short-circuit ratio. When the short-circuit ratio continues to decrease, the slope of the curve becomes smaller, and the speed of change of the adaptive control coefficient becomes slower, until it completely becomes voltage source control.

[0098] Please refer to Figure 6 , Figure 6 This is a schematic diagram of the structure of an adaptive control system for a wind turbine generator system based on short-circuit ratio identification provided by this application. The dotted box is regarded as the grid connection point. After injecting a disturbance signal into the grid connection point, the disturbance response signal component is extracted to determine the grid impedance and further calculate the short-circuit ratio. At this time, the adaptive adjustment weight coefficient K is determined according to the short-circuit ratio. a (i.e. adaptive control coefficient), Figure 6 In, K a The value of is equal to the weight of the current source control scheme in the overall control of the wind turbine (that is, the weight of the overall control of the grid-connected inverter), and the remaining weight (1-K a ) is equal to the weight of the voltage source control scheme in the overall control of the wind turbine. It can be seen that when K a When it is not equal to 1 or 0, the two control schemes run at the same time. By combining the two, the wind turbines under various grid strengths can be effectively controlled. When it is necessary to switch from one control scheme to another, according to Figure 2 It can be seen that the adaptive control coefficient does not change from 1 to 0 or from 0 to 1 instantly, but needs to gradually decrease or increase over a period of time, avoiding the uncertain disturbance caused by direct switching.

[0099] After the introduction of the adaptive control coefficient, the current source control scheme and the voltage source control scheme are no longer independent of each other. The advantages of the frequency and voltage support capabilities of the voltage source control scheme and the fast response capability of the current source control scheme can be combined. This not only ensures the regulatory adaptability of the system when it is more sensitive to changes in the short-circuit ratio, but also achieves a smooth transition between control schemes.

[0100] In summary, dual SOGI is used to extract disturbance response signals at the grid connection point and calculate the short-circuit ratio of the power grid. The short-circuit ratios obtained multiple times are used to determine the changing trend of the power grid. Based on this trend, the adaptive control coefficient corresponding to the currently obtained short-circuit ratio is determined. The proportion of the current source control scheme and the voltage source control scheme in the wind turbine is adjusted based on the control coefficient. Together, these two control schemes constitute the overall control of the wind turbine. By obtaining disturbance response signals through dual SOGI, real-time and effective extraction of disturbance response signals is achieved without changing the system structure or the original operating state. Complex calculation methods are also unnecessary, resulting in minimal impact on the system and reduced operational difficulty and cost. When switching control schemes, adjusting the adaptive control coefficient enables a smooth transition between the two control modes, avoiding the disturbance impact of direct switching that could reduce system stability. Furthermore, the adaptive control combining the two control schemes combines the excellent frequency and voltage support capabilities of the voltage source control scheme with the fast response capabilities of the current source control scheme, ensuring optimal control under various grid strengths.

[0101] Based on the above embodiment:

[0102] As a preferred embodiment, before determining the adaptive control coefficient corresponding to the currently obtained short-circuit ratio according to the change trend, the method further includes:

[0103] Get the voltage value at the grid connection point;

[0104] Determine whether the voltage value is within the preset voltage range;

[0105] If not, adjust the overall control of the wind turbine to a complete voltage source control scheme.

[0106] In order to ensure the stability of the power grid, in this application, during the normal operation of the wind turbine, the voltage in the power grid usually does not change much. However, when the wind turbine or the power grid is subject to a large interference or disturbance, the voltage of the power grid will fluctuate significantly. This significant fluctuation will not only cause the instability of the wind turbine, but also increase the error of the phase-locked control part in the wind turbine. Therefore, before performing adaptive control on the wind turbine, or while performing adaptive control, it is necessary to determine whether the voltage value of the grid connection point is within a preset voltage range (that is, to monitor the voltage at the grid connection point in real time and determine whether the voltage fluctuation amplitude exceeds the acceptable amplitude). When the voltage value is not within the preset voltage range, the control scheme is directly switched to a complete voltage source control scheme. This is because when the voltage variation amplitude is too large, there is already an uncertain disturbance inside the power grid. In order to avoid further expansion of the disturbance, it is possible to spend some disturbance to directly switch to the voltage source control scheme. Since the voltage source control scheme has a stronger support capacity for frequency and voltage than the current source control scheme, it can effectively reduce the interference caused to the power grid when the wind turbine or the power grid is subject to a large interference or disturbance. For example, assuming the preset ratio is 10%, the difference between the currently acquired voltage and the rated operating voltage must be calculated to determine whether the absolute value of the difference exceeds 10% of the rated operating voltage. If it does not exceed 10%, the wind turbine maintains normal operation. If it exceeds 10%, it indicates that the traditional phase-locked control error has increased, and the current source control scheme is no longer applicable. A direct switch to a voltage source control scheme is necessary. Based on this, when the voltage fluctuation is excessive, a direct switch to a full voltage source control scheme can ensure grid stability.

[0107] As a preferred embodiment, before determining the adaptive control coefficient corresponding to the currently obtained short-circuit ratio according to the change trend, the method further includes:

[0108] Get the voltage change rate at the grid connection point;

[0109] Determine whether the voltage change speed is greater than a preset change speed;

[0110] If so, adjust the overall control of the wind turbine to a complete voltage source control scheme.

[0111] In order to ensure the stability of the power grid, in this application, during the normal operation of the wind turbine, the voltage at the grid connection point will usually not change much. However, when the wind turbine or the power grid is subject to large interference or disturbance, the voltage at the grid connection point will fluctuate significantly. This significant fluctuation will not only cause the instability of the wind turbine, but also increase the error of the phase-locked control part in the wind turbine. Therefore, before performing adaptive control on the wind turbine, or while performing adaptive control, it is necessary to determine whether the voltage change speed is too fast. If it is too fast, the control scheme will be directly switched to a complete voltage source control scheme. According to the current low voltage fault ride-through standard for wind farms, it is required that when the voltage drops to 90% to 20% of the rated voltage, the connection with the grid must be guaranteed, and from the moment the voltage drops, the dynamic reactive current rise time of the wind farm shall not exceed 60ms, and the wind farm will respond quickly to provide reactive support current to help restore the voltage at the grid connection point. According to the above-mentioned ratio requirement standard, the maximum change speed, that is, the preset change speed V max for:

[0112]

[0113] Where pu is the unit of per unit value. If the per unit value of the reference voltage of the wind turbine in normal operation is set to 1, then the 90% to 20% in the above requirements correspond to 0.9pu and 0.2pu in the above formula respectively. When the wind turbine is operated according to the above adaptive control strategy, When , the control scheme is directly switched to a complete voltage source control scheme, where t is the unit time.

[0114] Based on this, when the voltage changes too quickly, directly switching to a complete voltage source control scheme can ensure the stability of the power grid.

[0115] As a preferred embodiment, determining the adaptive control coefficient corresponding to the currently obtained short-circuit ratio according to the change trend includes:

[0116] In the changing trend, determining the relationship between the short-circuit ratio corresponding to the currently obtained short-circuit ratio and the adaptive control coefficient;

[0117] The adaptive control coefficient corresponding to the currently obtained short circuit ratio is determined using the relationship and the currently obtained short circuit ratio.

[0118] Considering that when the short-circuit ratio approaches the applicable range limit of the currently applied control scheme, the adaptive control coefficient changes faster with the change of the short-circuit ratio, so as to speed up the proportion of investing in another control scheme to ensure the stability of the power grid, therefore, in this application, different short-circuit ratio ranges are set for different change trends, and the relationship between the change curves corresponding to the short-circuit ratios in different ranges is different. For details, please refer to Figure 2 , Figure 2 This is a function diagram of an adaptive control coefficient provided in this application. Assuming that the maximum value of the short-circuit ratio in the optimal applicable range of voltage source control is S min The short-circuit ratio of the optimal application range of current source control is S max , and the adjustment speed of the proportion of the control scheme is different under different short-circuit ratios. When the change of the short-circuit ratio has a more obvious effect on the wind turbine, the adjustment speed should be accelerated accordingly. In different change trends, there will be a point where the adjustment speed changes the most. At this point, the effect of switching the control scheme is the most obvious. Taking the reduction of the short-circuit ratio as an example, the short-circuit ratio starts to decrease from the optimal applicable range of the current source control. When the short-circuit ratio is reduced to S max Below, although the current source control can still ensure a good control effect, it cannot achieve the best control effect. As the short-circuit ratio continues to decrease, the control effect of the current source control continues to decrease, and the speed of the control effect decreases faster and faster. When the short-circuit ratio is reduced to a certain point, the control effect of the current source control is worse than that of the voltage source control. This point is the point where the above changes the most. When the change trend is a weakening trend, this point is called S mid_1 When the trend of change is an increasing trend, the point is called S mid_2 Among them, S min mid_1 mid_2 max , that is, taking the short circuit ratio reduction as an example, when the short circuit ratio is greater than S max When the short-circuit ratio is less than S, the current source control scheme can fully meet the control requirements of the wind turbine. max After that, the control effect of the current source control scheme begins to decline; when the short circuit ratio is less than S mid_1 After that, the control effect of the voltage source control scheme is better than that of the current source control scheme; when the short circuit ratio is less than S min After that, the voltage source control scheme can fully meet the control of the wind turbine. Similarly, if the short circuit ratio becomes larger, then S min_2 is the internal boundary and is the point with the fastest adjustment speed. In simple terms, when the change trend is different, the starting point (short-circuit ratio value) of the weight adjustment of the control scheme is different, and the actual switching process corresponds to Figure 2 It can be seen that when the short-circuit ratio changes from small to large, it is necessary to min Then we start to increase the proportion of current source control scheme, and when the short circuit ratio is closer to S mid_2 When the short-circuit ratio changes from large to small, the short-circuit ratio is less than S max Then the proportion of voltage source type solution is increased, and when the short circuit ratio is closer to S​​​mid_1 The faster the increase.

[0119] exist Figure 2 When the adaptive control coefficient is equal to 1, it means that the wind turbine completely adopts the current source control scheme. When the adaptive control coefficient is equal to 0, it means that the wind turbine completely adopts the voltage source control scheme. When the short circuit ratio changes from large to small, S mid_1 <Short Circuit Ratio max When the adaptive control coefficient is equal to S min <Short Circuit Ratio mid_1 When the adaptive control coefficient is equal to Short circuit ratio is less than or equal to S min When the short circuit ratio changes from small to large, S min <Short Circuit Ratio mid_2 When the adaptive control coefficient is equal to S min <Short Circuit Ratio mid_2 When the adaptive control coefficient is equal to Short circuit ratio greater than or equal to S max When the current source control scheme is changed completely. Among them, C1, C2, a1 and a2 are all different constants. The larger a1 and a2 are, the faster the adjustment speed of the corresponding adaptive control coefficient is. C1 and C2 are mainly used to calibrate the relationship in S min 、S mid_1 、S mid_2 and S max (For example, when the adaptive control coefficient is equal to 0.5 when the SCR is equal to 3 under the weakening trend, the adaptive control coefficient is equal to 0.5 by adjusting C1. The actual values ​​of C1, C2, a1 and a2 can be set according to the actual operation requirements of the wind turbine. For example, a1 can be set to 30, a2 to 10, C1 to 60, and C2 to 20. This application does not limit this.

[0120] Corresponding to Figure 2 It can be seen that Figure 2 The slope of the second curve in the short circuit ratio is 3 is smaller than the slope of the first curve in the short circuit ratio is 3, that is, ​​​​Taking the scenario of a reduced short-circuit ratio as an example, since the impact of the reduced short-circuit ratio on the system is more significant when the SCR is less than 3 than when the SCR is greater than 3, a faster activation of voltage source control is required to maintain stable system operation. Specifically, the closer to the cutoff point, the faster the adjustment should be, and then gradually slow down. Corresponding to the slope of the curve, if the current source control scheme and the voltage source control scheme at the cutoff point are set to the same proportion, that is, when the adaptive control coefficient is equal to 0.5, then C1 = 2a1 and C2 = 2a2. Based on this, by setting the relationship corresponding to the short-circuit ratio within different ranges with different change trends, the appropriate adaptive control coefficient can be accurately determined to ensure grid stability and better adapt to grid operation needs.

[0121] As a preferred embodiment, before determining the change trend of the power grid strength based on the currently obtained short-circuit ratio and the short-circuit ratios obtained for the previous N times, the method further includes:

[0122] When the short-circuit ratio is not less than a first preset short-circuit ratio, adjusting the overall control of the wind turbine generator set to a complete current source control scheme;

[0123] When the short-circuit ratio is not greater than a second preset short-circuit ratio, adjusting the overall control of the wind turbine generator set to a complete voltage source control scheme;

[0124] When the short-circuit ratio is greater than the second preset short-circuit ratio and less than the first preset short-circuit ratio, the step of determining a change trend of the power grid according to the currently obtained short-circuit ratio and the short-circuit ratios obtained for the previous N consecutive times is entered;

[0125] The second preset short-circuit ratio is smaller than the first preset short-circuit ratio.

[0126] In order to simply determine the adaptive control coefficient, in this application, taking into account the different applicable scopes of the two control schemes, the stability threshold value that can ensure the stable operation of the power grid can be determined in the applicable scope of the two control schemes respectively. Taking the current source control scheme as an example, although the applicable scope of the current source control scheme is an environment where the short-circuit ratio is greater than 3, in actual application, when the short-circuit ratio is close to 3, the control effect of the current source control scheme is significantly deteriorated, and the wind turbine generator set is prone to instability; when the short-circuit ratio is greater than 20, the current source control scheme has a better control effect on the wind turbine generator set. Therefore, the first preset short-circuit ratio is set to 20 (that is, S in the above embodiment). max ); Similarly, the voltage source type control scheme is applicable to environments where the short circuit ratio is less than 3. When the short circuit ratio is less than 1.5, the voltage source type control scheme has a better control effect on the wind turbine. Therefore, the second preset short circuit ratio is set to 1.5 (that is, S in the above embodiment). min). The specific set value needs to be set according to the actual application situation. It is only used as an example for explanation here. The actual value of the preset short-circuit ratio is not limited in this application. Based on this, after obtaining the short-circuit ratio, if it is determined that the short-circuit ratio is greater than the first preset weight or less than the second preset weight, the control scheme of the wind turbine can be set to complete current source control or complete voltage source control. This situation usually occurs when the wind turbine continues to operate in complete current source control or complete voltage source control, or when the wind turbine has just completely converted from one control scheme to another. Based on this, by setting two preset short-circuit ratios, if the actual short-circuit ratio is greater than the first preset weight or less than the second preset weight, it can be directly determined that the wind turbine selects a certain control scheme, and the adaptive control coefficient can be simply obtained without calculation.

[0127] As a preferred embodiment, while controlling the weights of the current source control scheme and the voltage source control scheme in the wind turbine generator set according to the adaptive control coefficient, the method further includes:

[0128] The weight of the active power droop control in the voltage source type control scheme and the phase-locked loop control in the current source type control scheme in the phase-locked control of the wind turbine is controlled according to the adaptive control coefficient;

[0129] The weight of the reactive power-voltage droop control in the voltage source type control scheme and the fixed reactive power outer loop control in the current source type control scheme in the reactive power outer loop control of the wind turbine is controlled according to the adaptive control coefficient.

[0130] In order to improve the stability of the wind turbine, in this application, in addition to combining the voltage source control scheme and the current source control scheme to jointly control the entire wind turbine, it is also necessary to combine the sub-schemes of these two control schemes in the details of the wind turbine to improve the reliability of the wind turbine. Figure 9 , Figure 9 This is a control block diagram of adaptive switching of a wind turbine provided by this application. Based on the structure of the original wind turbine, phase-locked adaptive control is adopted in the phase-locked part. The solid line represents the current source control part in the adaptive control, and the dotted line represents the voltage source control part in the adaptive control. When the system operation does not meet the phase-locked constraint conditions, the unit control is switched to voltage source control; and when the system operation meets the phase-locked constraint conditions, the active-frequency droop control in the voltage source control scheme is combined with the phase-locked loop control in the current source control scheme. The voltage source control scheme accounts for 1-K a , the current source control solution accounts for K a. When the short circuit ratio is relatively high, the complete use of phase-locked loop control can ensure the stability of the power grid. When the short circuit ratio decreases, the phase-locked loop control will have errors. At this time, it is necessary to use the active-frequency droop control in the voltage source control scheme to compensate for the phase-locked error of the phase-locked loop. As the short circuit ratio continues to decrease, the error of the phase-locked loop control continues to increase. When the system meets the phase-locked constraint conditions, the error is limited by the phase-locked constraint conditions, and the proportion of phase-locked loop control in the phase-locked control is gradually reduced. Gradually, the phase-locked loop control is completely transitioned to active-frequency droop control. Similarly, the increase in the short circuit ratio is a gradual transition from active-frequency droop control to phase-locked loop control. For the reactive outer loop control part, the reactive-voltage outer loop adaptive control is also adopted. The solid line represents the current source control part in the adaptive control, and the dotted line represents the voltage source control part in the adaptive control. The voltage source control scheme accounts for 1-K a , the current source control solution accounts for K a Similar to the above, this approach combines the reactive-voltage droop control of the voltage source control scheme with the constant reactive outer loop control of the current source control scheme. When the short-circuit ratio decreases and traditional constant reactive power control fails to guarantee voltage support, the appropriate introduction of droop control can provide a certain amount of reactive power support to the system, better ensuring stable operation of the unit under different short-circuit ratios. The actual proportion of these controls needs to be adjusted according to the actual short-circuit ratio. Based on this, the operating performance of the wind turbine can be improved.

[0131] As a preferred embodiment, before obtaining the disturbance response signal at the grid connection point using the dual SOGI solution, the method further includes:

[0132] Determining the current amplitude and disturbance frequency of the disturbance signal;

[0133] Obtain voltage and current signals at the grid connection point;

[0134] The dual SOGI solution is used to obtain the disturbance response signal at the grid connection point, including:

[0135] Utilizing the fundamental signal in the first SOGI power grid;

[0136] Determine the fundamental signal, determine the difference between the voltage signal and the current signal, and use the difference as the harmonic signal;

[0137] Amplify the harmonic signal by a preset multiple;

[0138] The second SOGI is used to obtain a signal at a disturbance frequency contained in the harmonic signal after amplification by a preset multiple, and the signal is used as a disturbance response signal.

[0139] In order to accurately obtain the disturbance response signal, we first need to understand the frequency characteristics of SOGI. Assuming that the detection frequency f' of SOGI is 50Hz, according to Figure 3 The Bode plot of SOGI can be determined by the above transfer function formula. Please refer to Figure 4 , Figure 4 This is a schematic diagram of a SOGI Bode diagram provided by this application. When the frequency of the disturbance signal f p When it is approximately equal to the detection frequency f' of SOGI, the amplitude of qu' of u' will change rapidly and significantly, and the phase will be directly reversed. It can be seen that SOGI is very sensitive to the input signal with a frequency of f'. Based on this, f' can be set equal to the frequency of the injected disturbance signal to accurately respond to the disturbance signal. When obtaining the disturbance response signal, since the content of the fundamental frequency signal in the collected input signal is much larger than the harmonic response signal, the disturbance response signal cannot be directly extracted from the input signal. It is necessary to first filter out the fundamental component and then amplify the harmonic response signal in order to accurately extract the components of the disturbance response signal. Please refer to Figure 5 , Figure 5 This is a flow chart of a method for obtaining a disturbance response signal using SOGI provided in this application. After collecting the input voltage signal at the grid connection point, SOGI is used to extract the fundamental signal therein, and the original input signal is subtracted from the fundamental signal to obtain the harmonic signal after filtering out the fundamental wave. The harmonic signal is then amplified by K. m times, and then use SOGI to extract the frequency f corresponding to the disturbance signal p The disturbance response signal can be accurately obtained.

[0140] As a preferred embodiment, before using the dual SOGI to obtain the disturbance response signal at the grid connection point, the method further includes:

[0141] Determine the rated current of the power grid when there is no disturbance and it is operating normally;

[0142] Determining a preset current amplitude of the disturbance signal according to the rated current;

[0143] A disturbance signal with a preset duration and a preset current amplitude is injected into the grid connection point.

[0144] In order to minimize the impact of the disturbance signal on the power grid of the wind turbine, it is necessary to minimize the current amplitude of the injected signal. However, if the disturbance signal is set too small, it will be difficult to extract the disturbance response signal from the power grid. Therefore, when injecting the disturbance signal, it is necessary to consider the above two points and pre-set the amplitude of the disturbance signal. Please refer to Figure 7 , Figure 7A schematic diagram of a disturbance signal injection method provided in this application, assuming that a three-phase symmetrical disturbance current signal I with a duration of t is injected sp ,have:

[0145]

[0146] ω p =2πf p

[0147] Among them, I pm is the amplitude of the disturbance signal, ω p is the angular velocity of the disturbance signal, φ p is the initial phase angle of the disturbance signal, f p is the frequency of the disturbance signal, ω p It needs to be set to be different from the fundamental signal. In order to minimize the impact on the original system, the amplitude needs to be reduced. However, if the amplitude is too small, it will be difficult to obtain the disturbance response signal later. Therefore, the amplitude of the disturbance signal needs to be set according to the amplitude of the signal in the power grid during normal operation. For example, I pm Set to 0.1% I gn , I gn is the amplitude of the signal in the power grid during normal operation; f p It also needs to be determined based on actual operating conditions, and the duration t also needs to be determined based on actual operating conditions.

[0148] Please refer to Figure 10 , Figure 10 The present application provides a schematic structural diagram of an adaptive control device for a wind turbine generator system based on short-circuit ratio identification, comprising:

[0149] Memory 21, for storing computer programs;

[0150] The processor 22 is configured to implement the steps of the above-mentioned method for adaptive control of a wind turbine generator system based on short-circuit ratio identification when executing a computer program.

[0151] For a detailed introduction to the adaptive control device for a wind turbine generator set based on short-circuit ratio identification provided in this application, please refer to the above-mentioned embodiment of the adaptive control method for a wind turbine generator set based on short-circuit ratio identification, and this application will not elaborate on it here.

[0152] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0153] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0154] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An adaptive control method for a wind turbine generator system based on short-circuit ratio identification, characterized in that: include: When a disturbance signal is detected to be injected into the power grid of the wind turbine generator system, a disturbance response signal at the grid connection point of the power grid is obtained by using a dual SOGI scheme; determining the impedance of the power grid when the power grid is disturbed by the disturbance response signal; determining the impedance of the power grid using the impedance when disturbed and the rated frequency of the power grid; Determining the short-circuit ratio according to the grid impedance and the rated capacity and preset rated voltage at the grid connection point; When the short-circuit ratio is not less than a first preset short-circuit ratio, adjusting the overall control of the wind turbine generator set to a complete current source control scheme; When the short-circuit ratio is not greater than a second preset short-circuit ratio, adjusting the overall control of the wind turbine generator set to a complete voltage source control scheme; When the short-circuit ratio is greater than the second preset short-circuit ratio and less than the first preset short-circuit ratio, determining a change trend of the power grid strength based on the currently obtained short-circuit ratio and the short-circuit ratios obtained N consecutive times, the change trend including an increasing trend and a decreasing trend, N being a positive integer, and the second preset short-circuit ratio being less than the first preset short-circuit ratio; In the change trend, determining a relationship between the short circuit ratio corresponding to the currently obtained short circuit ratio and an adaptive control coefficient; determining the adaptive control coefficient corresponding to the currently obtained short circuit ratio using the relationship and the currently obtained short circuit ratio; Adjusting the weights of the current source control scheme and the voltage source control scheme in the wind turbine generator set in the overall control of the wind turbine generator set according to the adaptive control coefficient; The sum of the weight of the current source control scheme in the overall control of the wind turbine generator set and the weight of the voltage source control scheme in the overall control of the wind turbine generator set is equal to 100%. Before obtaining the disturbance response signal at the grid connection point of the power grid using the dual SOGI solution, the method further includes: determining the current amplitude and disturbance frequency of the disturbance signal; obtaining the voltage signal and current signal at the grid connection point; Correspondingly, a dual SOGI scheme is used to obtain a disturbance response signal at a grid connection point of the power grid, including: using a first SOGI to obtain a fundamental signal in the power grid; determining a difference between the fundamental signal, the voltage signal, and the current signal, and using the difference as a harmonic signal; amplifying the harmonic signal by a preset multiple; and using a second SOGI to obtain a signal at the disturbance frequency contained in the harmonic signal amplified by the preset multiple, and using the signal as the disturbance response signal.

2. The adaptive control method for a wind turbine generator system based on short-circuit ratio identification according to claim 1, characterized in that: Before determining the adaptive control coefficient corresponding to the currently obtained short-circuit ratio according to the change trend, the method further includes: Obtaining a voltage value at the grid connection point; Determining whether the voltage value is within a preset voltage range; If not, the overall control of the wind turbine generator set is adjusted to the complete voltage source control scheme.

3. The adaptive control method for a wind turbine generator system based on short-circuit ratio identification according to claim 1, characterized in that: Before determining the adaptive control coefficient corresponding to the currently obtained short-circuit ratio according to the change trend, the method further includes: Obtaining a voltage change rate at the grid connection point; Determining whether the voltage change speed is greater than a preset change speed; If so, the overall control of the wind turbine generator set is adjusted to the complete voltage source control scheme.

4. The adaptive control method for a wind turbine generator system based on short-circuit ratio identification according to claim 1, characterized in that: While adjusting the weights of the current source control scheme and the voltage source control scheme in the wind turbine generator set in the overall control of the wind turbine generator set according to the adaptive control coefficient, the method further includes: Controlling the weight of the active power droop control in the voltage source control scheme and the phase-locked loop control in the current source control scheme in the phase-locked control of the wind turbine generator system according to the adaptive control coefficient; The weights of the reactive power-voltage droop control in the voltage source control scheme and the fixed reactive power outer loop control in the current source control scheme in the reactive power outer loop control of the wind turbine are controlled according to the adaptive control coefficient.

5. The adaptive control method for a wind turbine generator system based on short-circuit ratio identification according to claim 1, characterized in that: Determining the impedance of the power grid when the power grid is disturbed by the disturbance response signal includes: The ratio between the voltage amplitude and the current amplitude of the disturbance response signal is used as the impedance of the power grid when it is disturbed.

6. The adaptive control method for a wind turbine generator system based on short-circuit ratio identification according to any one of claims 1 to 5, characterized in that: Before using the dual SOGI to obtain the disturbance response signal at the grid connection point of the power grid, the method further includes: Determining the rated current of the power grid when it is operating normally without disturbance; determining a preset current amplitude of the disturbance signal according to the rated current; A disturbance signal having a preset duration and a strength of the preset current amplitude is injected into the grid connection point.

7. An adaptive control device for a wind turbine generator system based on short-circuit ratio identification, characterized in that: include: memory for storing computer programs; A processor is configured to implement the steps of the adaptive control method for a wind turbine generator system based on short-circuit ratio identification as claimed in any one of claims 1 to 6 when executing the computer program.

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