A method and system for optimizing the operational stability of a voltage source type wind turbine

Abstract

The application provides a voltage source type wind turbine operation stability optimization control method and system, comprising: obtaining required wind turbine parameter information, substituting the parameter information into a system short-circuit ratio calculation formula to calculate a wind turbine system short-circuit ratio; comparing the system short-circuit ratio with a pre-set initial short-circuit ratio to obtain a comparison result; adjusting a virtual damping coefficient according to the comparison result and the parameter information; and adjusting a wind turbine grid-connected point voltage according to the comparison result. The application adjusts the virtual damping coefficient according to the comparison result of the system short-circuit ratio and the pre-set initial short-circuit ratio and the parameter information, suppresses potential oscillation risks, improves wind turbine operation adaptability and dynamic performance, adjusts the wind turbine grid-connected point voltage according to the comparison result of the system short-circuit ratio and the pre-set initial short-circuit ratio, improves wind turbine voltage stability under different short-circuit ratios, and is suitable for grid-connected and off-grid operation scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new energy access and control, and particularly relates to a voltage source type wind turbine operation stability optimization control method and system. BACKGROUND

[0002] Conventional wind turbines achieve synchronization control with the power grid based on phase-locked loop control, which externally exhibits current source characteristics and does not actively support the power grid voltage and frequency. Although the inertia response, primary frequency modulation and fault voltage support of the wind turbine are achieved through the additional "grid-friendly" control link, the additional "grid-friendly" follow-up control is constrained as the conventional synchronous machine is largely replaced, and the power system frequency and voltage maintenance capability is severely challenged.

[0003] Voltage source type control technology with active frequency and voltage control and self-networking capability has attracted widespread attention. Virtual synchronous control is a typical method of voltage source type control of wind turbines, and related research mainly focuses on inertia, primary frequency support and stability improvement. The existing technology proposes an adaptive control method for virtual synchronous control of wind turbines, which adjusts the virtual damping coefficient through virtual synchronous speed fluctuation to improve dynamic performance and reduce oscillation risk. However, the existing technology still needs to solve the problem of performance improvement of wind turbines when the system strength and wind conditions of the unit change. SUMMARY

[0004] In order to solve the problem that the performance of wind turbines needs to be improved when the system strength and wind conditions of the unit change in the prior art, the present application provides a voltage source type wind turbine operation stability optimization control method, which comprises:

[0005] Obtaining the required parameter information of the wind turbine, and substituting the parameter information into a system short-circuit ratio calculation formula to calculate the system short-circuit ratio;

[0006] Comparing the system short-circuit ratio with the pre-set initial short-circuit ratio to obtain a comparison result;

[0007] Adjusting the virtual damping coefficient according to the comparison result and the parameter information;

[0008] Adjusting the grid-connected point voltage of the wind turbine according to the comparison result.

[0009] Preferably, the obtaining of the required parameter information of the wind turbine and the substitution of the parameter information into the pre-set system short-circuit ratio calculation formula to calculate the wind turbine system short-circuit ratio comprises:

[0010] Substituting the rotational inertia of the virtual synchronous machine, the rated angular frequency of the virtual synchronous machine, the captured wind power of the wind turbine, the output electric power and the virtual damping coefficient in the parameter information into an angular frequency calculation formula to calculate the virtual synchronous machine angular frequency;

[0011] substituting the virtual synchronous machine angular frequency and the virtual synchronous machine rated angular frequency into a virtual power angle calculation formula to calculate a virtual power angle;

[0012] substituting the grid point three-phase voltage and current in the parameter information into a machine terminal voltage calculation formula, an active power calculation formula and a reactive power calculation formula to calculate a machine terminal voltage actual value, a grid point actual output active power and a grid point actual output reactive power;

[0013] substituting the virtual power angle, the machine terminal voltage actual value, the grid point actual output active power, the grid point actual output reactive power, the rated voltage, the rated power in the parameter information and the collected low-pass filter into a system short-circuit ratio calculation formula to calculate a system short-circuit ratio;

[0014] The parameter information further comprises: a virtual synchronous machine moment of inertia, a virtual synchronous machine rated angular frequency, a wind turbine captured wind power, an output electric power, a virtual damping coefficient, a grid point three-phase voltage, a current, a rated voltage, a rated power and a low-pass filter.

[0015] Preferably, the system short-circuit ratio calculation formula is as shown in the following formula:

[0016]

[0017] In the above formula, SCR is a system short-circuit ratio, U n is a wind turbine rated voltage, P n is a wind turbine rated power, Q is a grid point actual output reactive power, P is a grid point actual output active power, U is a machine terminal voltage actual value, H(s) is a low-pass filter; and δ is a virtual power angle.

[0018] Preferably, the adjusting the virtual damping coefficient according to the comparison result and the parameter information comprises:

[0019] If the comparison result is that the system short-circuit ratio is not less than the pre-set initial short-circuit ratio, the virtual damping coefficient is increased according to a relationship between a wind turbine wind condition and a rated wind speed in the parameter information, otherwise the virtual damping coefficient is decreased according to the relationship between the wind turbine wind condition and the rated wind speed.

[0020] Preferably, the increasing the virtual damping coefficient according to the relationship between the wind turbine wind condition and the rated wind speed in the parameter information comprises:

[0021] if the wind condition of the wind turbine is less than the rated wind speed, increasing the virtual damping coefficient between the preset virtual damping coefficient initial value and the preset virtual damping coefficient maximum value, otherwise increasing the virtual damping coefficient between the first virtual damping coefficient and the virtual damping coefficient maximum value;

[0022] wherein the first virtual damping coefficient is obtained by adding the preset virtual damping coefficient initial value and the virtual damping increment under the rated wind speed in the parameter information;

[0023] The parameter information further comprises: wind condition of the wind turbine and virtual damping increment under the rated wind speed.

[0024] Preferably, the virtual damping coefficient is reduced according to the relationship between the wind condition of the wind turbine and the rated wind speed in the parameter information, comprising:

[0025] If the wind condition of the wind turbine is less than the rated wind speed, the virtual damping coefficient is reduced from the virtual damping coefficient initial value, otherwise the virtual damping coefficient is reduced from the first virtual damping coefficient.

[0026] Preferably, the grid-connected point voltage of the wind turbine is adjusted according to the comparison result, comprising:

[0027] If the comparison result is that the system short-circuit ratio is not less than the preset initial short-circuit ratio, the grid-connected point voltage of the wind turbine is adjusted by using the reactive power-voltage droop control type, otherwise the grid-connected point voltage of the wind turbine is adjusted by using the grid-side filter capacitor voltage closed-loop control type.

[0028] Preferably, the grid-connected point voltage of the wind turbine is adjusted by using the grid-side filter capacitor voltage closed-loop control, comprising:

[0029] The parameter information is substituted into the grid-side filter capacitor voltage control type to calculate the grid-connected point voltage reference value;

[0030] The grid-connected point voltage is controlled based on the grid-connected point voltage reference value;

[0031] wherein, the parameter information comprises: terminal voltage initial value, reactive power droop coefficient, wind turbine reactive power initial value and wind turbine reactive power reference value, grid-side filter capacitor voltage reference value, proportional coefficient of PI integrator and integral coefficient of PI integrator.

[0032] In still another aspect, the application further provides a voltage source type wind turbine operation stability optimization control system, comprising:

[0033] The calculation module is used for obtaining the parameter information of the required wind turbine, and substituting the parameter information into the system short-circuit ratio calculation formula to calculate the system short-circuit ratio;

[0034] a comparison module configured to compare the system short-circuit ratio with a preset initial short-circuit ratio, and obtain a comparison result;

[0035] a first adjustment module configured to adjust a virtual damping coefficient according to the comparison result and the parameter information;

[0036] a second adjustment module configured to adjust a grid-connected point voltage of the wind turbine generator according to the comparison result.

[0037] Preferably, the calculation module comprises:

[0038] an angular frequency calculation sub-module configured to calculate a virtual synchronous machine angular frequency by substituting a moment of inertia of the virtual synchronous machine, a rated angular frequency of the virtual synchronous machine, wind power captured by the wind turbine generator, output electric power and the virtual damping coefficient in the parameter information into an angular frequency calculation formula;

[0039] a power angle calculation sub-module configured to calculate a virtual power angle by substituting the virtual synchronous machine angular frequency and the rated angular frequency of the virtual synchronous machine into a virtual power angle calculation formula;

[0040] a parameter calculation sub-module configured to calculate an actual terminal voltage, actual output active power of the grid-connected point and actual output reactive power of the grid-connected point by substituting three-phase voltage and current of the grid-connected point in the parameter information into a terminal voltage calculation formula, an active power calculation formula and a reactive power calculation formula respectively;

[0041] a system short-circuit ratio calculation sub-module configured to calculate the system short-circuit ratio by substituting the virtual power angle, the actual terminal voltage, the actual output active power of the grid-connected point, the actual output reactive power of the grid-connected point, rated voltage, rated power and a low-pass filter in the parameter information into a system short-circuit ratio calculation formula;

[0042] Preferably, the parameter information further comprises the moment of inertia of the virtual synchronous machine, the rated angular frequency of the virtual synchronous machine, the wind power captured by the wind turbine generator, the output electric power, the virtual damping coefficient, the three-phase voltage and current of the grid-connected point, the rated voltage, the rated power and the low-pass filter.

[0043] Preferably, the system short-circuit ratio calculation formula is as shown in the following formula:

[0044]

[0045] In the above formula, SCR represents the system short-circuit ratio, U n represents rated voltage of the wind turbine generator, P n represents rated power of the wind turbine generator, Q represents actual output reactive power of the grid-connected point, P represents actual output active power of the grid-connected point, U represents actual terminal voltage, H(s) represents the low-pass filter, and δ represents the virtual power angle.

[0046] Preferably, the first adjusting module comprises:

[0047] a virtual damping coefficient adjusting submodule, configured to increase the virtual damping coefficient according to a relationship between a wind condition of the wind turbine and a rated wind speed in the parameter information if the comparison result is that the system short-circuit ratio is not less than the pre-set initial short-circuit ratio, or decrease the virtual damping coefficient according to the relationship between the wind condition of the wind turbine and the rated wind speed.

[0048] Preferably, the virtual damping coefficient adjusting submodule comprises:

[0049] a first adjusting unit, configured to increase the virtual damping coefficient between a pre-set virtual damping coefficient initial value and a pre-set virtual damping coefficient maximum value if the wind condition of the wind turbine is less than the rated wind speed, or increase the virtual damping coefficient between a pre-calculated first virtual damping coefficient and the virtual damping coefficient maximum value if the wind condition of the wind turbine is not less than the rated wind speed;

[0050] a second adjusting unit, configured to decrease the virtual damping coefficient from the virtual damping coefficient initial value if the wind condition of the wind turbine is less than the rated wind speed, or decrease the virtual damping coefficient from the first virtual damping coefficient if the wind condition of the wind turbine is not less than the rated wind speed;

[0051] wherein the first virtual damping coefficient is obtained by adding the virtual damping coefficient initial value and a virtual damping increment under the rated wind speed in the parameter information;

[0052] The parameter information further comprises: a virtual damping increment under the wind condition of the wind turbine and the rated wind speed.

[0053] Preferably, the second adjusting module comprises:

[0054] a grid-connected point voltage adjusting submodule, configured to adjust the grid-connected point voltage of the wind turbine by using reactive power-voltage droop control if the comparison result is that the system short-circuit ratio is not less than the pre-set initial short-circuit ratio, or adjust the grid-connected point voltage of the wind turbine by using grid-side filter capacitor voltage closed-loop control if the comparison result is that the system short-circuit ratio is less than the pre-set initial short-circuit ratio.

[0055] Preferably, the grid-connected point voltage adjusting submodule comprises:

[0056] a third adjusting unit, configured to calculate a grid-connected point voltage reference value by substituting the parameter information into a grid-side filter capacitor voltage control formula;

[0057] a first control unit, configured to control the grid-connected point voltage based on the grid-connected point voltage reference value;

[0058] wherein the parameter information comprises: a terminal voltage initial value, a reactive power droop coefficient, a wind turbine reactive power initial value and a wind turbine reactive power reference value; a grid-side filter capacitor voltage reference value, a proportional coefficient of a PI integrator and an integral coefficient of the PI integrator.

[0059] Compared with the prior art, the application has the following advantages:

[0060] The application provides a voltage source type wind turbine operation stability optimization control method, including: obtaining parameter information of a required wind turbine, and substituting the parameter information into a pre-set system short-circuit ratio calculation formula to obtain a system short-circuit ratio; comparing the system short-circuit ratio with a pre-set initial short-circuit ratio to obtain a comparison result; adjusting a virtual damping coefficient according to the comparison result and the parameter information; and adjusting a wind turbine grid-connected point voltage according to the comparison result. According to the comparison result of the system short-circuit ratio and the pre-set initial short-circuit ratio and the parameter information, the virtual damping coefficient is adjusted, potential oscillation risks are inhibited, and the wind turbine operation adaptability and dynamic performance are improved. According to the comparison result of the system short-circuit ratio and the pre-set initial short-circuit ratio, the wind turbine grid-connected point voltage is adjusted, the wind turbine voltage stability under different short-circuit ratios is improved, and the method is suitable for grid-connected and off-grid operation scenes. BRIEF DESCRIPTION OF DRAWINGS

[0061] Figure 1 A voltage source type wind turbine operation stability optimization control method flow chart is provided in the application.

[0062] Figure 2 A virtual synchronous control rotor motion equation link schematic diagram is provided in the application.

[0063] Figure 3 A virtual synchronous control reactive power-voltage control link schematic diagram is provided in the application.

[0064] Figure 4 A voltage source type wind turbine operation stability optimization control system structure diagram is provided in the application. DETAILED DESCRIPTION

[0065] The specific embodiments of the application are further described in detail below with reference to the accompanying drawings.

[0066] Embodiment 1

[0067] The application provides a voltage source type wind turbine operation stability optimization control method, as shown in Figure 1 The method includes the following steps:

[0068] Step S101: obtaining parameter information of a required wind turbine, and substituting the parameter information into a pre-set system short-circuit ratio calculation formula to obtain a wind turbine system short-circuit ratio;

[0069] Step S102: comparing the system short-circuit ratio with a pre-set initial short-circuit ratio to obtain a comparison result;

[0070] Step S103: adjusting a virtual damping coefficient according to the comparison result and the parameter information;

[0071] Step S104: adjusting a wind turbine generator set grid-connected point voltage according to the comparison result.

[0072] The step S101 comprises the following steps:

[0073] Step S101a: substituting a virtual synchronous machine rotational inertia, a virtual synchronous machine rated angular frequency, a wind turbine generator set captured wind power, an output electric power and a virtual damping coefficient in the parameter information into an angular frequency calculation formula to calculate a virtual synchronous machine angular frequency;

[0074] Step S101b: substituting the virtual synchronous machine angular frequency and the virtual synchronous machine rated angular frequency into a virtual power angle calculation formula to calculate a virtual power angle;

[0075] Step S101c: substituting a grid-connected point three-phase voltage and current in the parameter information into a machine terminal voltage calculation formula, an active power calculation formula and a reactive power calculation formula to calculate a machine terminal voltage actual value, a grid-connected point actual output active power and a grid-connected point actual output reactive power;

[0076] Step S101d: substituting the virtual power angle, the machine terminal voltage actual value, the grid-connected point actual output active power, the grid-connected point actual output reactive power, a rated voltage, a rated power and a low-pass filter in the parameter information into a system short-circuit ratio calculation formula to calculate a system short-circuit ratio;

[0077] The parameter information comprises: a virtual synchronous machine rotational inertia, a virtual synchronous machine rated angular frequency, a wind turbine generator set captured wind power, an output electric power, a virtual damping coefficient, a grid-connected point three-phase voltage, a current, a rated voltage, a rated power and a low-pass filter.

[0078] The step S101 comprises the following specific process:

[0079] The virtual synchronous control is a strategy for realizing a voltage source type control of the wind turbine generator set, a power outer ring simulates a synchronous generator rotor motion equation and an excitation control, a rotor motion equation generates a wind turbine generator set voltage reference phase, a reactive power-voltage droop link generates a voltage reference amplitude, and an equation is shown in formula (1):

[0080]

[0081] In the above formula, J is a virtual synchronous machine rotational inertia; ω is a virtual synchronous machine angular frequency; ω0 is a virtual synchronous machine rated angular frequency; D is a virtual damping coefficient, δ is a virtual power angle; P m is a wind turbine generator set captured wind power; P e is a wind turbine generator set output electric power; U0 is a machine terminal voltage initial value; Ure Q0is the reactive initial value of the wind turbine; Q is the reactive reference value of the wind turbine; k is the reactive droop coefficient; and U is the voltage reference value of the grid-connected point. ref Q0is the reactive initial value of the wind turbine; Q is the reactive reference value of the wind turbine; k is the reactive droop coefficient; and U is the voltage reference value of the grid-connected point. q Q0is the reactive initial value of the wind turbine; Q is the reactive reference value of the wind turbine; k is the reactive droop coefficient; and U is the voltage reference value of the grid-connected point.

[0082] Considering that the inductive reactance in the line impedance is much larger than the resistance, the resistance can be ignored, and the power transmission equation can be obtained as follows:

[0083]

[0084] In the above formula, U is the actual value of the terminal voltage; P is the actual output active power of the grid-connected point; Q is the actual output reactive power of the grid-connected point; E is the voltage equivalent value of the wind turbine system converted to the wind power side; X is the equivalent impedance between the system and the wind turbine; and δ is the virtual power angle.

[0085] In the above formula, U is the actual value of the terminal voltage; P is the actual output active power of the grid-connected point; Q is the actual output reactive power of the grid-connected point; E is the voltage equivalent value of the wind turbine system converted to the wind power side; X is the equivalent impedance between the system and the wind turbine; and δ is the virtual power angle.

[0086] The impedance expression can be obtained from formula (2) as follows:

[0087]

[0088] In the above formula, X is the equivalent impedance between the system and the wind turbine; U is the actual value of the terminal voltage; P is the actual output active power of the grid-connected point; Q is the actual output reactive power of the grid-connected point; and δ is the virtual power angle.

[0089] Considering the power fluctuation, the low-pass filter H(s) can be used for smoothing processing as follows:

[0090]

[0091] In the above formula, X is the equivalent impedance between the system and the wind turbine; U is the actual value of the terminal voltage; P is the actual output active power of the grid-connected point; Q is the actual output reactive power of the grid-connected point; δ is the virtual power angle; and H(s) is the low-pass filter.

[0092] The system strength can be represented by the short-circuit ratio, and according to the definition of the short-circuit ratio combined with formula (4), the system short-circuit ratio calculation formula can be obtained as follows:

[0093]

[0094] In the above formula, SCR is the system short-circuit ratio, U n is the rated voltage of the wind turbine, P n is the rated power of the wind turbine, Q is the actual output reactive power of the grid-connected point, P is the actual output active power of the grid-connected point, U is the actual value of the terminal voltage, H(s) is the low-pass filter; and δ is the virtual power angle.

[0095] Step S102: comparing the system short circuit ratio with a pre-set initial short circuit ratio to obtain a comparison result;

[0096] Step 103: adjusting a virtual damping coefficient according to the comparison result and the parameter information, specifically:

[0097] When the comparison result is that the system short circuit ratio is not less than the pre-set initial short circuit ratio, the virtual damping coefficient is increased according to the relationship between the wind condition of the wind turbine and the rated wind speed in the parameter information, otherwise the virtual damping coefficient is decreased according to the relationship between the wind condition of the wind turbine and the rated wind speed.

[0098] Wherein, increasing the virtual damping coefficient according to the relationship between the wind condition of the wind turbine and the rated wind speed in the parameter information comprises:

[0099] If the wind condition of the wind turbine is less than the rated wind speed, the virtual damping coefficient is increased between a pre-set virtual damping coefficient initial value and a pre-set virtual damping coefficient maximum value, otherwise the virtual damping coefficient is increased between a pre-calculated first virtual damping coefficient and the virtual damping coefficient maximum value.

[0100] Decreasing the virtual damping coefficient according to the relationship between the wind condition of the wind turbine and the rated wind speed comprises:

[0101] If the wind condition of the wind turbine is less than the rated wind speed, the virtual damping coefficient is decreased from the virtual damping coefficient initial value, otherwise the virtual damping coefficient is decreased from the first virtual damping coefficient.

[0102] Wherein, the first virtual damping coefficient is obtained by adding a pre-set virtual damping coefficient initial value and a virtual damping increment under the rated wind speed in the parameter information.

[0103] The specific process of step S103 is:

[0104] The virtual damping coefficient of the voltage source type wind turbine has a significant impact on the stability of the unit grid connection, and the size of the damping coefficient is closely related to the system strength and the unit working condition.

[0105] When the system strength is large, the system frequency is relatively stable when SCR≥SCR0, at this time the virtual damping coefficient of the voltage source type wind turbine can be reduced to improve the dynamic response characteristics of the system;

[0106] When the system strength is small, that is, SCR<SCR0, the system frequency fluctuation risk is large, and the unit should increase the virtual damping coefficient to ensure the stability of the unit grid connection.

[0107] Wherein, SCR0 is a selected constant, which can be selected as 3.

[0108] For the operating conditions of the unit, referring to conventional wind turbine units, when the wind speed is below the rated wind speed, the electrical damping torque coefficient of the wind turbine unit is positive and the unit is relatively stable. When the wind speed is above the rated wind speed, the electrical damping torque coefficient is negative and it is easy to cause the system shaft oscillation.

[0109] Similarly, for voltage source wind turbines, when they operate below the rated wind speed, their virtual damping coefficient can remain unchanged, but when they operate above the rated wind speed, the virtual damping coefficient should be appropriately increased.

[0110] In summary, the virtual damping of voltage source wind turbines should be adaptively adjusted according to system strength and wind conditions to achieve better steady-state and dynamic performance, and satisfy the following functional relationship:

[0111]

[0112] In equation (6), when the wind speed V is less than the rated wind speed, as the SCR decreases, D gradually increases from the initial value D0, and the value range is D0~D max ;

[0113] When the wind speed V is greater than or equal to the rated wind speed, D increases from the initial value D0 to D0+ΔD. As the SCR decreases, D gradually increases, with a value ranging from D0+ΔD to D. max .

[0114] When the wind speed V is less than the rated wind speed, as the SCR increases, D gradually decreases from the initial value D0.

[0115] When the wind speed V is greater than or equal to the rated wind speed, as the SCR increases, D gradually decreases from the first virtual damping coefficient D0+ΔD.

[0116] The first virtual damping coefficient is obtained by adding the pre-set initial value D0 of the virtual damping coefficient and the virtual damping increment ΔD at the rated wind speed in the parameter information; D max Maximum amplitude limit.

[0117] The following is in conjunction with the appendix Figure 2 The equations of motion for virtual synchronous control rotor are introduced below:

[0118] Wind turbine captures wind power P m The difference between the output power of the wind turbine and the output power of the wind turbine is calculated, and the product of the virtual damping coefficient D and the virtual synchronous machine angular frequency deviation is subtracted from the difference. The result is then adjusted to an amplitude of [missing value]. The integral stage generates a virtual synchronization angular frequency, which is then added to the rated angular frequency ω0 to obtain the reference value ω of the virtual synchronizer angular frequency. * The virtual synchronous electrical angle reference value θ is obtained through integration. * .

[0119] Wherein, the virtual damping coefficient D is determined by f(SCR, V), and the virtual synchronous angular frequency is (ω-ω0).

[0120] Step S104: adjusting the wind turbine grid-connected point voltage according to the comparison result, specifically:

[0121] If the comparison result is that the system short-circuit ratio is not less than the pre-set initial short-circuit ratio, the reactive power-voltage droop control is used to adjust the wind turbine grid-connected point voltage, otherwise the grid-side filter capacitor voltage closed-loop control is used to adjust the wind turbine grid-connected point voltage.

[0122] Wherein, the grid-side filter capacitor voltage closed-loop control for adjusting the wind turbine grid-connected point voltage comprises:

[0123] The parameter information is substituted into the grid-side filter capacitor voltage control formula to calculate the grid-connected point voltage reference value;

[0124] The grid-connected point voltage is controlled based on the grid-connected point voltage reference value;

[0125] Wherein, the parameter information comprises: machine terminal voltage initial value, reactive power droop coefficient, wind turbine reactive power initial value and wind turbine reactive power reference value, grid-side filter capacitor voltage reference value, proportional coefficient of PI integrator and integral coefficient of PI integrator.

[0126] The specific process of step S104 is:

[0127] The reactive power-voltage control link takes the stability of the grid-connected point voltage as the target, and is directly related to the system strength,

[0128] When SCR≥SCR0, the grid-connected point voltage is relatively stable, and the voltage source type wind turbine can adopt the reactive power-voltage droop control, and the reactive power-voltage droop control formula is as follows:

[0129] U ref =U0+k q (Q ref -Q0) (7)

[0130] In the above formula, U ref is the grid-connected point voltage reference value, U0 is the given initial value of the machine terminal voltage, k q is the reactive power droop coefficient, Q ref is the given reactive power reference value of the wind turbine, and Q0 is the given reactive power initial value of the wind turbine.

[0131] When SCR<SCR0, the grid-connected point voltage of the unit fluctuates greatly, and the closed-loop control of the voltage needs to be realized to ensure stability, the grid-side filter capacitor voltage closed-loop control is adopted in the application to realize the stable control of the grid-connected point voltage, and the grid-side filter capacitor voltage closed-loop control formula is as follows:

[0132]

[0133] In the formula, U ref is a grid-connected point voltage reference value, U0 is a given initial value of terminal voltage, k q is a reactive droop coefficient, Q ref is a given reactive reference value of the wind turbine, Q0 is a given initial reactive value of the wind turbine, k pi is a proportion of the PI integrator, k ii is an integral coefficient of the PI integrator, U c_ref is a grid-side filter capacitor reference value, U c is a grid-side filter capacitor voltage value.

[0134] The following will be described in conjunction with the accompanying Figure 3 The virtual synchronous control reactive-voltage control link is introduced:

[0135] When SCR<SCR0, the "0" node is connected, the given reactive reference value Q ref of the wind turbine is subtracted from the initial reactive value Q0 of the wind turbine, and the difference is multiplied by the proportional coefficient kq, and then added to the initial terminal voltage U0 to directly generate the terminal voltage reference value U ref of the wind turbine.

[0136] When SCR≥SCR0, the "1" node is connected, the given reactive reference value Q ref of the wind turbine is subtracted from the initial reactive value Q0 of the wind turbine, and the difference is multiplied by the proportional coefficient kq, and then added to the initial terminal voltage U0, and the value after the superimposed filter capacitor voltage deviation is processed by the PI link to generate the terminal voltage reference value U ref of the wind turbine.

[0137] Embodiment 2

[0138] The application also provides a voltage source type wind turbine operation stability optimization control system, as shown in Figure 4 , comprising:

[0139] A calculation module is configured to obtain required wind turbine parameter information, and calculate a system short-circuit ratio by substituting the parameter information into a system short-circuit ratio calculation formula.

[0140] A comparison module is configured to compare the system short-circuit ratio with a pre-set initial short-circuit ratio to obtain a comparison result.

[0141] A first adjustment module is configured to adjust a virtual damping coefficient according to the comparison result and the parameter information.

[0142] A second adjustment module is configured to adjust a wind turbine grid-connected point voltage according to the comparison result.

[0143] The calculation module comprises:

[0144] The angular frequency calculation submodule is configured to calculate a virtual synchronous machine angular frequency by substituting the moment of inertia of the virtual synchronous machine, the rated angular frequency of the virtual synchronous machine, the wind power captured by the wind turbine, the output electric power and the virtual damping coefficient in the parameter information into an angular frequency calculation formula.

[0145] The power angle calculation submodule is configured to calculate a virtual power angle by substituting the virtual synchronous machine angular frequency and the rated angular frequency of the virtual synchronous machine into a virtual power angle calculation formula.

[0146] The parameter calculation submodule is configured to calculate an actual terminal voltage, an actual output active power of the grid-connected point and an actual output reactive power of the grid-connected point by substituting the three-phase voltage and current of the grid-connected point in the parameter information into a terminal voltage calculation formula, an active power calculation formula and a reactive power calculation formula respectively.

[0147] The system short-circuit ratio calculation submodule is configured to calculate a system short-circuit ratio by substituting the virtual power angle, the actual terminal voltage, the actual output active power of the grid-connected point, the actual output reactive power of the grid-connected point, the rated voltage, the rated power and the low-pass filter in the parameter information into a system short-circuit ratio calculation formula.

[0148] The parameter information comprises the moment of inertia of the virtual synchronous machine, the rated angular frequency of the virtual synchronous machine, the wind power captured by the wind turbine, the output electric power, the virtual damping coefficient, the three-phase voltage of the grid-connected point, the current, the rated voltage, the rated power and the low-pass filter.

[0149] The calculation module comprises the following specific processes:

[0150] The virtual synchronous control is a strategy for realizing voltage source type control of the wind turbine, and the power outer ring simulates a synchronous generator rotor motion equation and excitation control. The rotor motion equation generates a wind turbine voltage reference phase, and a reactive-voltage droop link generates a voltage reference amplitude. The equation is shown in formula (1):

[0151]

[0152] In the above formula, J is the moment of inertia of the virtual synchronous machine; ω is the angular frequency of the virtual synchronous machine; ω0 is the rated angular frequency of the virtual synchronous machine; D is the virtual damping coefficient; δ is the virtual power angle; P m is the wind power captured by the wind turbine; P e is the output electric power of the wind turbine; U0 is the initial terminal voltage; U re is the voltage reference value of the grid-connected point; Q0 is the initial reactive power of the wind turbine; Q ref is the reactive power reference value of the wind turbine; k q is the reactive droop coefficient.

[0153] Considering that the inductive reactance is much larger than the resistance in the line impedance, the resistance can be ignored, and the power transmission equation can be obtained as follows:

[0154]

[0155] In the above formula, U is the actual value of the terminal voltage; P is the actual output active power of the grid-connected point; Q is the actual output reactive power of the grid-connected point; E is the voltage equivalent value of the wind turbine system converted to the wind power side; X is the equivalent impedance between the system and the wind turbine; and δ is the virtual power angle.

[0156] Wherein, U, P, Q can be obtained by the wind turbine collecting the three-phase voltage and current of the grid-connected point.

[0157] The impedance expression can be obtained from formula (2) as follows:

[0158]

[0159] In the above formula, X is the equivalent impedance between the system and the wind turbine; U is the actual value of the terminal voltage; P is the actual output active power of the grid-connected point; Q is the actual output reactive power of the grid-connected point; and δ is the virtual power angle.

[0160] Considering the power fluctuation, the low-pass filter H(s) can be used for smoothing processing as follows:

[0161]

[0162] In the above formula, X is the equivalent impedance between the system and the wind turbine; U is the actual value of the terminal voltage; P is the actual output active power of the grid-connected point; Q is the actual output reactive power of the grid-connected point; δ is the virtual power angle; and H(s) is the low-pass filter.

[0163] The system strength can be represented by the short-circuit ratio, and according to the definition of the short-circuit ratio combined with formula (4), the system short-circuit ratio calculation formula can be obtained as follows:

[0164]

[0165] In the above formula, SCR is the system short-circuit ratio, U n is the rated voltage of the wind turbine, P n is the rated power of the wind turbine, Q is the actual output reactive power of the grid-connected point, P is the actual output active power of the grid-connected point, U is the actual value of the terminal voltage, H(s) is the low-pass filter; and δ is the virtual power angle.

[0166] The first adjusting module comprises:

[0167] The virtual damping coefficient adjustment submodule is configured to increase the virtual damping coefficient according to a relationship between the wind condition of the wind turbine and the rated wind speed in the parameter information if the comparison result is that the system short-circuit ratio is not less than the preset initial short-circuit ratio, or decrease the virtual damping coefficient according to the relationship between the wind condition of the wind turbine and the rated wind speed.

[0168] The virtual damping coefficient adjustment submodule comprises:

[0169] The first adjustment unit is configured to increase the virtual damping coefficient between a preset virtual damping coefficient initial value and a preset virtual damping coefficient maximum value if the wind turbine speed is less than the rated wind speed, or increase the virtual damping coefficient between a first virtual damping coefficient calculated in advance and the virtual damping coefficient maximum value if the wind turbine speed is not less than the rated wind speed.

[0170] The second adjustment unit is configured to decrease the virtual damping coefficient from the virtual damping coefficient initial value if the wind condition of the wind turbine is less than the rated wind speed, or decrease the virtual damping coefficient from the first virtual damping coefficient if the wind condition of the wind turbine is not less than the rated wind speed.

[0171] The first virtual damping coefficient is obtained by adding the virtual damping coefficient initial value and a virtual damping increment at the rated wind speed in the parameter information.

[0172] The virtual damping coefficient adjustment submodule specifically comprises the following steps:

[0173] The virtual damping coefficient of the voltage source type wind turbine has a significant influence on the grid-connection stability of the wind turbine, and the size of the virtual damping coefficient is closely related to the system strength and the operating condition of the wind turbine.

[0174] When the system strength is large, the system frequency is relatively stable when SCR is greater than or equal to SCR0, and the virtual damping coefficient of the voltage source type wind turbine can be reduced to improve the dynamic response characteristics of the system.

[0175] When the system strength is small, i.e., SCR is less than SCR0, the system frequency fluctuation risk is large, and the virtual damping coefficient of the wind turbine should be increased to ensure the grid-connection stability of the wind turbine.

[0176] SCR0 is a selected constant, which can be selected as 3.

[0177] For the operating condition of the wind turbine, the virtual damping coefficient of the voltage source type wind turbine can be kept unchanged when the wind turbine operates below the rated wind speed, and the virtual damping coefficient should be appropriately increased when the wind turbine operates above the rated wind speed.

[0178] In summary, the virtual damping of the voltage source type wind turbine should be self-adaptively adjusted according to the system strength and wind condition to realize better steady-state and dynamic performance and meet the following function relationship:

[0179]

[0180] In formula (6), when the wind speed V is less than the rated wind speed, D gradually increases from the initial value D0 to D max as the SCR decreases, and the value range is D0~D max .

[0181] When the wind speed V is greater than or equal to the rated wind speed, D increases from the initial value D0 to D0+ΔD, and gradually increases as the SCR decreases, and the value range is D0+ΔD~D max .

[0182] When the wind speed V is less than the rated wind speed, D gradually decreases from the initial value D0 as the SCR increases.

[0183] When the wind speed V is greater than or equal to the rated wind speed, D gradually decreases from the first virtual damping coefficient D0+ΔD as the SCR increases.

[0184] The first virtual damping coefficient is obtained by adding the pre-set virtual damping coefficient initial value D0 and the virtual damping increment ΔD under the rated wind speed in the parameter information; D max is the maximum limit.

[0185] The following will be combined with the accompanying drawings Figure 2 The rotor motion equation part of the virtual synchronous control is introduced:

[0186] The wind turbine captures wind power P m and subtracts the virtual damping coefficient D and the virtual synchronous angle frequency deviation product from the wind turbine output electric power, and generates a virtual synchronous angle frequency through an integral element with an amplitude of The virtual synchronous angle frequency and the rated angle frequency ω0 are added to obtain the virtual synchronous machine angle frequency reference value ω * , and the virtual synchronous electric angle reference value θ * is obtained through an integral element.

[0187] The virtual damping coefficient D is determined by f(SCR, V), and the virtual synchronous angle frequency is (ω-ω0).

[0188] The second adjusting module comprises:

[0189] The grid-connected point voltage adjusting sub-module is configured to adjust the grid-connected point voltage of the wind turbine by using reactive power-voltage droop control if the comparison result is that the system short-circuit ratio is not less than the pre-set initial short-circuit ratio, and otherwise, adjust the grid-connected point voltage of the wind turbine by using grid-side filter capacitor voltage closed-loop control.

[0190] The grid-connected point voltage adjusting sub-module comprises:

[0191] The third adjusting unit is configured to substitute the parameter information into a grid-side filter capacitor voltage control formula to obtain a grid-connected point voltage reference value;

[0192] The first control unit is configured to control the grid-connected point voltage based on the grid-connected point voltage reference value.

[0193] The parameter information comprises a terminal voltage initial value, a reactive power droop coefficient, a wind turbine reactive power initial value and a wind turbine reactive power reference value; a grid-side filter capacitor voltage reference value, a proportional coefficient of a PI integrator and an integral coefficient of the PI integrator.

[0194] The third adjusting unit has the following specific process:

[0195] The reactive power-voltage control link aims to stabilize the grid-connected point voltage and is directly related to the system strength,

[0196] When the SCR is greater than or equal to the SCR0, the grid-connected point voltage is relatively stable, and the voltage source type wind turbine can adopt the reactive power-voltage droop control, and the reactive power-voltage droop control formula is as follows:

[0197] U ref = U0 + k q (Q ref -Q0) (7)

[0198] In the formula, U ref is the grid-connected point voltage reference value, U0 is the terminal voltage given initial value, k q is the reactive power droop coefficient, Q ref is the wind turbine given reactive power reference value, and Q0 is the wind turbine given reactive power initial value.

[0199] When the SCR is less than the SCR0, the grid-connected point voltage fluctuation of the wind turbine is large, and closed-loop control of the voltage needs to be implemented to guarantee stability, the grid-side filter capacitor voltage closed-loop control is adopted in the application to realize stable control of the grid-connected point voltage, and the grid-side filter capacitor voltage closed-loop control formula is as follows:

[0200]

[0201] In the formula, U ref is the grid-connected point voltage reference value, U0 is the terminal voltage given initial value, k q is the reactive power droop coefficient, Q ref is the wind turbine given reactive power reference value, Q0 is the wind turbine given reactive power initial value, k pi is the proportional coefficient of the PI integrator, and k ii is the integral coefficient of the PI integrator.c_ref U is a network side filter capacitor reference value c U is a network side filter capacitor voltage value.

[0202] The accompanying drawings are incorporated in and constitute a part of this specification and will be understood by those skilled in the art. Figure 3 The virtual synchronous control reactive-voltage control link is introduced as follows:

[0203] When SCR < SCR0, the "0" node is connected, the wind turbine generator is given a reactive reference value Q ref and the wind turbine generator reactive initial value Q0, the difference is obtained, multiplied by the proportional coefficient kq, and then added to the terminal voltage terminal initial value U0, to directly generate the wind turbine generator terminal voltage reference value U ref .

[0204] When SCR ≥ SCR0, the "1" node is connected, the wind turbine generator is given a reactive reference value Q ref and the wind turbine generator reactive initial value Q0, the difference is obtained, multiplied by the proportional coefficient kq, and then added to the terminal voltage terminal initial value U0, to directly generate the wind turbine generator terminal voltage reference value U ref .

[0205] Those skilled in the art will appreciate that embodiments of the application can be provided as methods, systems, or computer program products. Accordingly, the application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage media, etc.) having computer usable program code embodied in the medium.

[0206] The application is described with reference to the flowcharts and / or block diagrams of the methods, apparatus (systems), and computer program products according to embodiments of the application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The flowcharts and / or block diagrams can include one or more flows and / or blocks that implement the functions specified in the flowcharts and / or block diagrams. Figure 1 The flowcharts and / or block diagrams can include one or more flows and / or blocks that implement the functions specified in the flowcharts and / or block diagrams.

[0207] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the flow Figure 1 one or more flows and / or blocks Figure 1 one or more blocks or multiple blocks.

[0208] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the flow Figure 1 one or more flows and / or blocks Figure 1 one or more blocks or multiple blocks.

[0209] Finally, it should be noted that the above-mentioned embodiments are merely used to illustrate the technical solutions of the present application, rather than limiting the same. Even though the present application has been described in detail with reference to the above-mentioned embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced equivalently, and any modification or replacement without departing from the spirit and scope of the present application should be covered within the protection scope of the claims of the present application.

Claims

1. A method for optimizing the operational stability of a voltage source wind turbine, characterized in that, The method comprises the following steps: acquiring parameter information of the wind turbine, and substituting the parameter information into a system short-circuit ratio calculation formula to calculate a system short-circuit ratio of the wind turbine; comparing the system short-circuit ratio with a preset initial short-circuit ratio to obtain a comparison result; adjusting a virtual damping coefficient according to the comparison result and the parameter information; adjusting a grid-connected point voltage of the wind turbine according to the comparison result; wherein the adjusting of the virtual damping coefficient according to the comparison result and the parameter information comprises: if the comparison result is that the system short-circuit ratio is not less than the preset initial short-circuit ratio, then increasing the virtual damping coefficient according to a relationship between a wind condition of the wind turbine and a rated wind speed in the parameter information, otherwise decreasing the virtual damping coefficient according to the relationship between the wind condition of the wind turbine and the rated wind speed.

2. The method of claim 1, wherein, The acquiring of the parameter information of the wind turbine, and the substituting of the parameter information into the preset system short-circuit ratio calculation formula to calculate the system short-circuit ratio of the wind turbine comprises: substituting a rotational inertia of a virtual synchronous machine, a rated angular frequency of the virtual synchronous machine, a wind power captured by the wind turbine, an output electric power and the virtual damping coefficient in the parameter information into an angular frequency calculation formula to calculate an angular frequency of the virtual synchronous machine; substituting the angular frequency of the virtual synchronous machine and the rated angular frequency of the virtual synchronous machine into a virtual power angle calculation formula to calculate a virtual power angle; substituting a grid-connected point three-phase voltage and current in the parameter information into a machine terminal voltage calculation formula, an active power calculation formula and a reactive power calculation formula to calculate a machine terminal voltage actual value, an actual output active power of the grid-connected point and an actual output reactive power of the grid-connected point; substituting the virtual power angle, the machine terminal voltage actual value, the actual output active power of the grid-connected point, the actual output reactive power of the grid-connected point, a rated voltage, a rated power and a low-pass filter in the parameter information into the system short-circuit ratio calculation formula to calculate the system short-circuit ratio; wherein the parameter information comprises the rotational inertia of the virtual synchronous machine, the rated angular frequency of the virtual synchronous machine, the wind power captured by the wind turbine, the output electric power, the virtual damping coefficient, the grid-connected point three-phase voltage, the current, the rated voltage, the rated power and the low-pass filter.

3. The method of claim 2, wherein, The system short-circuit ratio calculation formula is as shown in the following formula: In the formula, SCR is the system short-circuit ratio, U n is the rated voltage of the wind turbine, P n is the rated power of the wind turbine, Q is the actual output reactive power of the grid-connected point, P is the actual output active power of the grid-connected point, U is the actual value of the terminal voltage, H(s) is a low-pass filter; and δ is a virtual power angle.

4. The method of claim 1, wherein, The increasing of the virtual damping coefficient according to the relationship between the wind condition of the wind turbine and the rated wind speed in the parameter information comprises: if the wind condition of the wind turbine is less than the rated wind speed, then increasing the virtual damping coefficient between a preset virtual damping coefficient initial value and a preset virtual damping coefficient maximum value, otherwise increasing the virtual damping coefficient between a first virtual damping coefficient calculated in advance and the virtual damping coefficient maximum value; wherein the first virtual damping coefficient is obtained by adding the virtual damping increment at the rated wind speed in the parameter information to the preset virtual damping coefficient initial value; the parameter information further comprises the wind condition of the wind turbine and the virtual damping increment at the rated wind speed.

5. The method of claim 4, wherein, The decreasing of the virtual damping coefficient according to the relationship between the wind condition of the wind turbine and the rated wind speed in the parameter information comprises: If the wind condition of the wind turbine is less than the rated wind speed, the virtual damping coefficient is reduced from the initial value of the virtual damping coefficient, otherwise the virtual damping coefficient is reduced from the first virtual damping coefficient.

6. The method of claim 1, wherein, The adjusting the grid-connected point voltage of the wind turbine according to the comparison result comprises: If the comparison result is that the system short-circuit ratio is not less than the pre-set initial short-circuit ratio, the grid-connected point voltage of the wind turbine is adjusted by using reactive power-voltage droop control, otherwise the grid-connected point voltage of the wind turbine is adjusted by using grid-side filter capacitor voltage closed-loop control.

7. The method of claim 6, wherein, The adjusting the grid-connected point voltage of the wind turbine by using grid-side filter capacitor voltage closed-loop control comprises: The grid-connected point voltage reference value is calculated by substituting the initial value of the terminal voltage, the reactive power droop coefficient, the initial value of the wind turbine reactive power and the wind turbine reactive power reference value, the grid-side filter capacitor voltage reference value, the proportional coefficient of the PI integrator and the integral coefficient of the PI integrator in the parameter information into the grid-side filter capacitor voltage control formula; The grid-connected point voltage is controlled based on the grid-connected point voltage reference value; The parameter information further comprises: the initial value of the terminal voltage, the reactive power droop coefficient, the initial value of the wind turbine reactive power and the wind turbine reactive power reference value, the grid-side filter capacitor voltage reference value, the proportional coefficient of the PI integrator and the integral coefficient of the PI integrator.

8. A voltage source type wind turbine operating stability optimization control system, characterized in that, It comprises: The calculation module is configured to obtain the parameter information of the required wind turbine, and substitute the parameter information into a system short-circuit ratio calculation formula to calculate a system short-circuit ratio; The comparison module is configured to compare the system short-circuit ratio with a pre-set initial short-circuit ratio to obtain a comparison result; The first adjustment module is configured to adjust a virtual damping coefficient according to the comparison result and the parameter information; The second adjustment module is configured to adjust the grid-connected point voltage of the wind turbine according to the comparison result; The virtual damping coefficient adjustment submodule is configured to increase the virtual damping coefficient according to the relationship between the wind condition of the wind turbine and the rated wind speed in the parameter information if the comparison result is that the system short-circuit ratio is not less than the pre-set initial short-circuit ratio, otherwise reduce the virtual damping coefficient according to the relationship between the wind condition of the wind turbine and the rated wind speed.

9. The system of claim 8, wherein, The calculation module comprises: The angular frequency calculation submodule is configured to substitute the rotational inertia of the virtual synchronous machine, the virtual synchronous machine rated angular frequency, the wind turbine captured wind power, the output electric power and the virtual damping coefficient in the parameter information into an angular frequency calculation formula to calculate a virtual synchronous machine angular frequency; The power angle calculation submodule is configured to substitute the virtual synchronous machine angular frequency and the virtual synchronous machine rated angular frequency into a virtual power angle calculation formula to calculate a virtual power angle; The parameter calculation submodule is configured to substitute the grid-connected point three-phase voltage and current in the parameter information into a terminal voltage calculation formula, an active power calculation formula and a reactive power calculation formula to calculate a terminal voltage actual value, a grid-connected point actual output active power and a grid-connected point actual output reactive power; The system short-circuit ratio calculation submodule is configured to substitute the virtual power angle, the terminal voltage actual value, the grid-connected point actual output active power, the grid-connected point actual output reactive power, the rated voltage, the rated power and the low-pass filter in the parameter information into a system short-circuit ratio calculation formula to calculate a system short-circuit ratio; The parameter information includes: a rotational inertia of the virtual synchronous machine, a rated angular frequency of the virtual synchronous machine, a wind power captured by the wind turbine, an output electric power, a virtual damping coefficient, a three-phase voltage at a grid-connected point, a current, a rated voltage, a rated power, and a low-pass filter.

10. The system of claim 9, wherein, The system short-circuit ratio calculation formula is as follows: In the formula, SCR is the system short-circuit ratio, U n is the rated voltage of the wind turbine, P n is the rated power of the wind turbine, Q is the actual output reactive power of the grid-connected point, P is the actual output active power of the grid-connected point, U is the actual value of the terminal voltage, H(s) is a low-pass filter; and δ is a virtual power angle.

11. The system of claim 10, wherein, The virtual damping coefficient adjustment submodule comprises: The first adjustment unit is configured to increase the virtual damping coefficient between a preset virtual damping coefficient initial value and a preset virtual damping coefficient maximum value if the wind condition of the wind turbine is less than the rated wind speed, and otherwise increase the virtual damping coefficient between a first virtual damping coefficient calculated in advance and the virtual damping coefficient maximum value; The second adjustment unit is configured to decrease the virtual damping coefficient from the virtual damping coefficient initial value if the wind condition of the wind turbine is less than the rated wind speed, and otherwise decrease the virtual damping coefficient from the first virtual damping coefficient. The first virtual damping coefficient is obtained by adding the virtual damping coefficient initial value and a virtual damping increment at the rated wind speed in the parameter information. The parameter information further comprises: a wind condition of the wind turbine and a virtual damping increment at the rated wind speed.

12. The system of claim 10, wherein, The second adjustment module comprises: The grid-connected point voltage adjustment submodule is configured to adjust the grid-connected point voltage of the wind turbine by using reactive power-voltage droop control if the comparison result is that the system short-circuit ratio is not less than the preset initial short-circuit ratio, and otherwise adjust the grid-connected point voltage of the wind turbine by using grid-side filter capacitor voltage closed-loop control.

13. The system of claim 12, wherein, The grid-connected point voltage adjustment submodule comprises: The third adjustment unit is configured to calculate the grid-connected point voltage reference value by substituting a terminal voltage initial value, a reactive power droop coefficient, a wind turbine reactive power initial value, and a wind turbine reactive power reference value in the parameter information, a grid-side filter capacitor voltage reference value, a proportional coefficient of a PI integrator, and an integral coefficient of the PI integrator into a grid-side filter capacitor voltage control formula. The first control unit is configured to control the grid-connected point voltage based on the grid-connected point voltage reference value. The parameter information comprises: a terminal voltage initial value, a reactive power droop coefficient, a wind turbine reactive power initial value, and a wind turbine reactive power reference value; a grid-side filter capacitor voltage reference value, a proportional coefficient of a PI integrator, and an integral coefficient of the PI integrator.

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