A method and system for load reduction control of a wind turbine under extreme gusts

Abstract

The application discloses a load reduction control method and system of a wind turbine under extreme gust, comprising: through judging the current wind wheel speed deviation and the wind wheel speed deviation change rate, when exceeding the set threshold, superimposing an additional pitch rate on the pitch instruction; through judging the current cabin acceleration, when the cabin acceleration exceeds the threshold, after a delay period, the wind wheel speed is greater than the rated wind wheel speed and the wind wheel acceleration is greater than the threshold, superimposing the additional pitch rate on the pitch instruction; through judging the yaw error measured by the cabin wind vane, when the yaw error exceeds the yaw error threshold, reducing the set value of the wind wheel speed, i.e. reducing the impeller speed, to reduce the load of the wind turbine. The application can effectively reduce the component load of the wind turbine under extreme gust, and realize the lightweight design of the unit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind power generation, and particularly to a load reduction control method and system for a wind turbine under extreme gust, a storage medium and a computing device. BACKGROUND

[0002] Under the background of carbon neutrality, wind power generation technology has made remarkable achievements, and is rapidly developing towards high efficiency, high reliability, low cost and intelligence. Wind turbines are also moving towards large-scale, high-tower, lightweight and intelligent. Therefore, at the beginning of the design of the wind turbine, some new control technologies and methods must be used to optimize the load of each component of the unit. For the extreme gust wind condition of the wind turbine, the wind turbine often appears blade limit load, hub limit load, yaw limit load and tower limit load. However, the existing proportional integral control and nonlinear gain control method cannot effectively solve the problem of large limit load of the wind turbine under gust. Therefore, a load reduction control scheme for extreme gust wind condition is needed. SUMMARY

[0003] The first object of the present application is to overcome the shortcomings and deficiencies of the prior art, and to provide a load reduction control method for a wind turbine under extreme gust, which can effectively reduce the component load of the wind turbine under extreme gust and realize lightweight design of the unit.

[0004] The second object of the present application is to provide a load reduction control system for a wind turbine under extreme gust.

[0005] The third object of the present application is to provide a storage medium.

[0006] The fourth object of the present application is to provide a computing device.

[0007] The first object of the present application is achieved by the following technical scheme: a load reduction control method for a wind turbine under extreme gust, comprising:

[0008] Gust priority pitch: by judging the current wind wheel speed deviation and the wind wheel speed deviation change rate, when the set threshold is exceeded, an additional pitch rate is superimposed on the pitch command;

[0009] Gust overspeed suppression: by judging the current nacelle acceleration, when the nacelle acceleration exceeds the threshold, after a delay period, the wind wheel speed is greater than the rated wind wheel speed and the wind wheel acceleration is greater than the threshold, an additional pitch rate is superimposed on the pitch command;

[0010] Nonlinear speed setting: by judging the yaw error measured by the nacelle wind vane, when the yaw error exceeds the yaw error threshold, the set value of the wind wheel speed is reduced, i.e. the rotor speed is reduced, to reduce the load of the wind turbine.

[0011] Preferably, in gust priority pitch, the average wind speed experienced by the wind turbine under gust condition reaches the cut-out wind speed from the rated wind speed in a short time, the rotor speed increases significantly, and the rotor speed shows an accelerating upward trend; at this time, the rotor speed minus the rated speed is defined as the rotor speed deviation, if the product of the current rotor speed deviation and the rotor speed deviation rate of change exceeds the set threshold, it is judged as gust condition, an additional pitch rate is superimposed on the pitch command, as follows:

[0012] First, define the rotor speed deviation as follows:

[0013]

[0014] In the formula, Δω r represents the rotor speed deviation; ω r represents the rotor speed after filtering out high-frequency noise; ω rated represents the rated speed of the rotor; if represents the judgment condition; else represents other conditions; if the rotor speed ω r is higher than the rated speed of the rotor ω rated , the rotor speed deviation Δω r is equal to the difference between the rotor speed and the rated speed of the rotor, i.e. ω r - ω rated , otherwise the rotor speed deviation Δω r is equal to 0;

[0015] Based on the rotor speed deviation, the rotor speed deviation rate of change is defined as follows:

[0016]

[0017] In the formula, represents the rotor speed deviation rate of change; d(Δω r ) / dt represents the derivative of the rotor speed deviation with respect to time t; if the rotor speed deviation Δω r is accelerating upward, the rotor speed deviation rate of change is equal to the derivative of the rotor speed deviation with respect to time t, otherwise the rotor speed deviation rate of change is equal to 0.

[0018] Based on the rotor speed deviation and the rotor speed deviation rate of change, the priority pitch additional pitch rate is defined as follows:

[0019]

[0020] In the formula, δ represents the priority pitch additional pitch rate; δ E represents the priority pitch additional pitch rate preset value; E βrepresents the maximum threshold of the product of the rotational speed deviation and the rotational speed deviation change rate, which changes with the average pitch angle; P e represents the current generator measured power; k represents the power coefficient, which is set in the interval of 0 to 1; P rated represents the generator rated power; and represents the logical and operation;

[0021] Finally, the additional pitch rate is superimposed on the pitch command as follows:

[0022]

[0023] In the formula, β1 represents the pitch angle command transmitted to the blade 1 pitch system; β2 represents the pitch angle command transmitted to the blade 2 pitch system; and β3 represents the pitch angle command transmitted to the blade 3 pitch system. represents the pitch angle command of blade 1 output by the controller; represents the pitch angle command of blade 2 output by the controller; represents the pitch angle command of blade 3 output by the controller; and ∫δdt represents the integral of the priority pitch additional pitch rate into the additional pitch angle.

[0024] Preferably, in the gust overspeed suppression, the average wind speed experienced by the wind wheel of the wind turbine reaches the cut-out wind speed from the rated wind speed in a short time under the gust working condition, at which time the nacelle acceleration will increase significantly, and the rotational speed will show an accelerating upward trend. Since the nacelle acceleration responds to the gust more quickly, the nacelle acceleration is used as a pre-judgment condition, and after a delay time, it is monitored whether the rotational speed of the wind wheel has an accelerating trend. If it exceeds the threshold, an additional pitch rate is superimposed on the pitch command, which is as follows:

[0025] The delay time is realized by a timer. When the nacelle acceleration exceeds the acceleration threshold, the timer starts timing; when the nacelle acceleration is lower than the acceleration threshold, the timer is initialized to zero. Wherein, the timer of the nacelle acceleration as a pre-judgment condition is defined as follows:

[0026]

[0027] In the formula, t n represents the time of the timer at time n; t n-1 represents the time of the timer at time n-1; and Δt represents the time step from time n-1 to n. represents the nacelle fore-aft direction acceleration; M fa represents the nacelle fore-aft acceleration threshold; if represents the judgment condition behind; else represents other cases.

[0028] Based on the timer and the rotational speed deviation change rate, the overspeed suppression additional pitch rate is defined as follows:

[0029]

[0030] where λ represents overspeed inhibition additional pitch rate; λ E represents overspeed inhibition additional pitch rate preset value; represents wind wheel speed deviation change rate; H β represents wind wheel speed deviation change rate threshold; T E represents time threshold of timer; and represents logical and operation;

[0031] Finally, the additional pitch rate is superimposed on the pitch command as follows:

[0032]

[0033] where β1 represents pitch angle command transmitted to blade 1 pitch system; β2 represents pitch angle command transmitted to blade 2 pitch system; and β3 represents pitch angle command transmitted to blade 3 pitch system; represents pitch angle command of blade 1 output by controller; represents pitch angle command of blade 2 output by controller; represents pitch angle command of blade 3 output by controller; and ∫λdt represents overspeed inhibition additional pitch rate integrated into additional pitch angle.

[0034] Preferably, in the nonlinear speed setting, when the yaw error angle measured by the nacelle wind vane exceeds the threshold value, the orientation of the wind wheel deviates greatly from the wind direction, at this time, the wind wheel is not directly against the wind, the wind wheel is subjected to a large unbalanced bending moment, and by reducing the impeller speed, the load on the wind wheel will be reduced simultaneously; when the wind wheel is finally against the wind, at this time, the yaw error is reduced, and the wind wheel speed is restored to the rated speed operation; wherein the impeller speed setting value is defined as follows:

[0035]

[0036] where ω set represents impeller speed setting value; ω rated represents rated impeller speed; φ represents yaw error angle after low-pass filtering of the yaw error measured by the nacelle wind vane; f(φ) represents nonlinear part of speed setting value, which is a lookup table function, and the speed setting value offset is looked up according to the yaw error angle; abs(φ) represents absolute value of yaw error angle; and φ E represents threshold value of absolute value of yaw error angle; if represents judgment condition; and else represents other cases.

[0037] The second object of the application is achieved by the following technical scheme: a load reduction control system of a wind turbine under extreme gust, comprising:

[0038] The gust-priority pitch control module determines the current rotor speed deviation and the rate of change of the rotor speed deviation. When the deviation exceeds the set threshold, it adds an additional pitch rate to the pitch control instruction.

[0039] The gust overspeed suppression module judges the current nacelle acceleration. When the nacelle acceleration exceeds the threshold, after a delay period, the wind rotor speed is greater than the rated speed of the wind rotor and the wind rotor acceleration is greater than the threshold, an additional pitch rate is superimposed on the pitch command;

[0040] The nonlinear speed setting module judges the yaw error measured by the nacelle wind vane. When the yaw error exceeds the yaw error threshold, the set value of the wind rotor speed is reduced, that is, the impeller speed is reduced to reduce the load of the wind turbine.

[0041] Preferably, in the gust priority pitch control module, when the wind turbine is in a gust condition, the average wind speed felt by the rotor reaches the cut-out wind speed from the rated wind speed in a short period of time, the rotor speed increases significantly, and the speed shows an accelerating upward trend; at this time, the rotor speed minus the rated speed is defined as the rotor speed deviation. If the product of the current rotor speed deviation and the rotor speed deviation change rate exceeds the set threshold, it is determined to be a gust condition, and an additional pitch rate is superimposed on the pitch control instruction, as follows:

[0042] First, define the wind rotor speed deviation as follows:

[0043]

[0044] Where Δω r Indicates the wind wheel speed deviation; ω r Indicates the wind wheel speed after filtering out high-frequency noise; ω rated Indicates the rated speed of the wind wheel; if indicates the following judgment condition; else indicates other conditions; if the wind wheel speed ω r Higher than the rated speed of the wind wheelω rated When the wind wheel speed deviation Δω r Equal to the difference between the wind rotor speed and the rated speed of the wind rotor, that is, ω r -ω rated , otherwise the wind wheel speed deviation Δω r =0;

[0045] Based on the wind rotor speed deviation, the wind rotor speed deviation change rate is defined as follows:

[0046]

[0047] Where, Indicates the rate of change of the wind wheel speed deviation; d(Δω r ) / dt represents the derivative of the rotor speed deviation with respect to time t; if the rotor speed deviation Δωr Rising acceleration, wind speed deviation rate of change equal to the derivative of the wind speed deviation with respect to time t, otherwise the wind speed deviation rate of change is equal to 0.

[0048] Based on the wind speed deviation and the wind speed deviation rate of change, the priority pitch additional pitch rate is defined as follows:

[0049]

[0050] In the formula, δ represents the priority pitch additional pitch rate; δ E represents the priority pitch additional pitch rate preset value; E β represents the maximum threshold of the product of the speed deviation and the speed deviation rate of change, which changes with the average pitch angle; P e represents the current generator measured power; k represents the power coefficient, which is set in the interval of 0 to 1; P rated represents the generator rated power; and represents the logical and operation;

[0051] Finally, the additional pitch rate is superimposed on the pitch command as follows:

[0052]

[0053] In the formula, β1 represents the pitch angle command transmitted to the blade 1 pitch system; β2 represents the pitch angle command transmitted to the blade 2 pitch system; β3 represents the pitch angle command transmitted to the blade 3 pitch system; represents the pitch angle command of blade 1 output by the controller; represents the pitch angle command of blade 2 output by the controller; represents the pitch angle command of blade 3 output by the controller; and ∫δdt represents the integration of the priority pitch additional pitch rate into the additional pitch angle.

[0054] Preferably, in the gust overspeed suppression module, the wind speed experienced by the wind wheel of the wind turbine reaches the cut-out wind speed from the rated wind speed in a short time under gust working condition, at this time the nacelle acceleration will increase significantly, and the speed presents an accelerating upward trend. Since the nacelle acceleration responds faster to the gust, the nacelle acceleration is used as a prediction condition, and after a delay time, it is monitored whether the wind wheel speed has an accelerating trend, if it exceeds the threshold, an additional pitch rate is superimposed on the pitch command, as follows:

[0055] The delay time is realized by a timer, when the nacelle acceleration exceeds the acceleration threshold, the timer starts timing; when the nacelle acceleration is lower than the acceleration threshold, the timer is initialized to zero; wherein the timer of the nacelle acceleration as a prediction condition is defined as follows:

[0056]

[0057] where t n denotes the time of the timer at time n; t n-1 denotes the time of the timer at time n-1; Δt denotes the time step from time n-1 to n; denotes the cabin fore-aft direction acceleration; M fa denotes the cabin fore-aft acceleration threshold; if denotes the following is the judgment condition; else denotes other cases;

[0058] Based on the timer and the wind wheel speed deviation rate of change, the overspeed inhibition additional pitch rate is defined as follows:

[0059]

[0060] where λ denotes the overspeed inhibition additional pitch rate; λ E denotes the overspeed inhibition additional pitch rate preset value; denotes the wind wheel speed deviation rate of change; H β denotes the wind wheel speed deviation rate of change threshold; T E denotes the time threshold of the timer; and denotes the logical and operation;

[0061] Finally, the additional pitch rate is superimposed on the pitch command as follows:

[0062]

[0063] where β1 denotes the pitch angle command transmitted to the blade 1 pitch system; β2 denotes the pitch angle command transmitted to the blade 2 pitch system; β3 denotes the pitch angle command transmitted to the blade 3 pitch system; denotes the pitch angle command of blade 1 output by the controller; denotes the pitch angle command of blade 2 output by the controller; denotes the pitch angle command of blade 3 output by the controller; ∫λdt denotes the overspeed inhibition additional pitch rate integrated into the additional pitch angle.

[0064] Preferably, in the nonlinear speed setting module, when the cabin wind vane measures that the yaw error angle exceeds the threshold value, the orientation of the wind wheel deviates greatly from the wind direction, at this time the wind wheel is not directly against the wind, the wind wheel receives a large unbalanced bending moment, and by reducing the impeller speed, the load received by the wind wheel will be reduced simultaneously; when the wind wheel is finally yawed against the wind, at this time the yaw error is reduced, and the wind wheel speed is restored to the rated speed operation; wherein the impeller speed setting value is defined as follows:

[0065]

[0066] where ω setIndicates the impeller speed setting value; ω rated represents the rated speed of the impeller; φ represents the yaw error angle after low-pass filtering of the yaw error measured by the cabin wind vane; f(φ) represents the nonlinear part of the speed setting value, which is a lookup function that looks up the speed setting value offset according to the yaw error angle; abs(φ) represents the absolute value of the yaw error angle; φ E Indicates the threshold of the absolute value of the yaw error angle; if indicates that the following is a judgment condition; else indicates other situations.

[0067] The third object of the present invention is achieved through the following technical solution: a storage medium stores a program, and when the program is executed by a processor, the above-mentioned load reduction control method of the wind turbine under extreme gusts is implemented.

[0068] The fourth object of the present invention is achieved through the following technical solution: a computing device, comprising a processor and a memory for storing a program executable by the processor, wherein when the processor executes the program stored in the memory, the above-mentioned load reduction control method for the wind turbine under extreme gusts is implemented.

[0069] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0070] 1. The present invention proposes a load reduction control method for wind turbines operating under extreme gust conditions based on the judgment of the wind rotor speed deviation, nacelle acceleration and yaw error changes, which can reduce the extreme loads on the impeller, yaw bearing and tower.

[0071] 2. The load reduction control method proposed in the present invention is based on the existing sensors of the wind turbine, including the impeller speed sensor, the nacelle acceleration sensor and the wind vane sensor. There is no need to add additional measurement sensors and the hardware cost is not increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 This is an architectural diagram of the system of the present invention. DETAILED DESCRIPTION

[0073] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0074] Example 1

[0075] This embodiment discloses a load reduction control method for a wind turbine generator set under extreme gusts, the details of which are as follows:

[0076] a. Gust-priority pitch control: By judging the current rotor speed deviation and the rate of change of the rotor speed deviation, when it exceeds the set threshold, an additional pitch rate is superimposed on the pitch control instruction.

[0077] Under gust condition, the average wind speed experienced by the wind wheel of a wind turbine increases from rated wind speed to cut-out wind speed in a short time, and the rotation speed of the wind wheel increases obviously and presents an accelerating upward trend. At this time, the wind wheel rotation speed deviation is defined as the wind wheel rotation speed minus the rated rotation speed. If the product of the current wind wheel rotation speed deviation and the wind wheel rotation speed deviation change rate exceeds a set threshold value, the gust condition is judged, and an additional pitch rate is superimposed on the pitch command, as follows:

[0078] Firstly, the wind wheel rotation speed deviation is defined as follows:

[0079]

[0080] In the formula, Δω r represents the wind wheel rotation speed deviation; ω r represents the wind wheel rotation speed after filtering high-frequency noise; ω rated represents the rated rotation speed of the wind wheel; if represents the judgment condition behind; else represents other conditions; if the wind wheel rotation speed ω r is higher than the rated rotation speed ω rated of the wind wheel, the wind wheel rotation speed deviation Δω r is equal to the difference between the wind wheel rotation speed and the rated rotation speed of the wind wheel, i.e. ω r - ω rated , otherwise the wind wheel rotation speed deviation Δω r is equal to 0.

[0081] Based on the wind wheel rotation speed deviation, the wind wheel rotation speed deviation change rate is defined as follows:

[0082]

[0083] In the formula, represents the wind wheel rotation speed deviation change rate; d(Δω r ) / dt represents the derivative of the wind wheel rotation speed deviation with respect to time t; if the wind wheel rotation speed deviation Δω r is accelerating upward, the wind wheel rotation speed deviation change rate is equal to the derivative of the wind wheel rotation speed deviation with respect to time t, otherwise the wind wheel rotation speed deviation change rate is equal to 0.

[0084] Based on the wind wheel rotation speed deviation and the wind wheel rotation speed deviation change rate, the priority pitch additional pitch rate is defined as follows:

[0085]

[0086] In the formula, δ represents the priority pitch additional pitch rate; δ E represents the priority pitch additional pitch rate preset value; E β represents the maximum threshold value of the product of the rotation speed deviation and the rotation speed deviation change rate, which changes with the change of the average pitch angle, and the current threshold value E is obtained by looking up the current pitch angle.β ; P e represents the current generator measured power; k represents the power coefficient, parameter setting in the interval of 0 to 1; P rated represents the generator rated power; and represents the logical and operation;

[0087] Finally, the additional pitch rate is superimposed on the pitch command as follows:

[0088]

[0089] In the formula, β1 represents the pitch angle command transmitted to the blade 1 pitch system; β2 represents the pitch angle command transmitted to the blade 2 pitch system; β3 represents the pitch angle command transmitted to the blade 3 pitch system; represents the pitch angle command of blade 1 output by the controller; represents the pitch angle command of blade 2 output by the controller; represents the pitch angle command of blade 3 output by the controller; ∫δdt represents the integral of the priority pitch additional pitch rate into the additional pitch angle.

[0090] b, gust overspeed suppression: through the judgment of the current nacelle acceleration, when the nacelle acceleration exceeds the threshold value, after a time delay, the wind wheel speed is greater than the rated speed of the wind wheel and the wind wheel acceleration is greater than the threshold value, the additional pitch rate is superimposed on the pitch command.

[0091] Under gust working condition, the average wind speed felt by the wind wheel of the wind turbine reaches the cut-out wind speed from the rated wind speed in a short time, at this time the nacelle acceleration will increase obviously, and the speed presents an accelerating upward trend. Since the nacelle acceleration responds to the gust faster, the nacelle acceleration is used as a pre-judgment condition, and after a time delay, it is monitored whether the wind wheel speed has an accelerating trend, if it exceeds the threshold value, the additional pitch rate is superimposed on the pitch command, as follows:

[0092] The time delay is realized by a timer, when the nacelle acceleration exceeds the acceleration threshold value, the timer starts timing; when the nacelle acceleration is lower than the acceleration threshold value, the timer is initialized to zero; wherein the timer of the nacelle acceleration as a pre-judgment condition is defined as follows:

[0093]

[0094] In the formula, t n represents the time of the timer at time n; t n-1 represents the time of the timer at time n-1; Δt represents the time step from time n-1 to n; represents the nacelle fore-aft direction acceleration; M fa represents the nacelle fore-aft acceleration threshold value; if represents the judgment condition behind; else represents other conditions;

[0095] Based on the timer and the wind wheel speed deviation change rate, the overspeed inhibition additional pitch rate is defined as follows:

[0096]

[0097] In the formula, λ represents the overspeed inhibition additional pitch rate; λ E represents the overspeed inhibition additional pitch rate preset value; represents the wind wheel speed deviation change rate; H β represents the wind wheel speed deviation change rate threshold; T E represents the time threshold of the timer; and represents the logical and operation;

[0098] Finally, the additional pitch rate is superimposed on the pitch instruction as follows:

[0099]

[0100] In the formula, β1 represents the pitch angle instruction transmitted to the blade 1 pitch system; β2 represents the pitch angle instruction transmitted to the blade 2 pitch system; and β3 represents the pitch angle instruction transmitted to the blade 3 pitch system. represents the pitch angle instruction of blade 1 output by the controller; represents the pitch angle instruction of blade 2 output by the controller; represents the pitch angle instruction of blade 3 output by the controller; and ∫λdt represents the integral of the overspeed inhibition additional pitch rate into the additional pitch angle.

[0101] c. Nonlinear speed setting: by judging the yaw error measured by the nacelle wind vane, when the yaw error exceeds the yaw error threshold, the set value of the wind wheel speed is reduced, that is, the rotor speed is reduced, so as to reduce the load of the wind turbine.

[0102] When the nacelle wind vane measures that the yaw error angle exceeds the threshold, the orientation of the wind wheel deviates greatly from the wind direction, at this time the wind wheel is not directly against the wind, and the wind wheel receives a larger unbalanced bending moment. By reducing the rotor speed, the load received by the wind wheel will be reduced at the same time. When the wind wheel is finally yawed to the wind, at this time the yaw error is reduced, and the rotor speed is restored to the rated speed operation. Wherein, the rotor speed set value is defined as follows:

[0103]

[0104] In the formula, ω set represents the rotor speed set value; ω ratedrepresents the rated speed of the impeller; φ represents the yaw error angle after low-pass filtering of the yaw error measured by the nacelle wind vane; f(φ) represents the non-linear part of the speed setting value, which is a table function, and the speed setting value offset is obtained by looking up the table according to the yaw error angle; abs(φ) represents the absolute value of the yaw error angle; φ E represents the threshold value of the absolute value of the yaw error angle; if represents that the following is a judgment condition; else represents other cases.

[0105] Embodiment 2

[0106] This embodiment discloses a load reduction control system of a wind turbine under extreme gust, as shown in the figure, the system comprises the following functional modules: Figure 1

[0107] The gust priority pitch module adds an additional pitch rate to the pitch instruction by judging the current wind wheel speed deviation and the wind wheel speed deviation change rate when the set threshold is exceeded;

[0108] The gust overspeed suppression module adds an additional pitch rate to the pitch instruction by judging the current nacelle acceleration when the nacelle acceleration exceeds the threshold, after a delay of a period of time, the wind wheel speed is greater than the rated speed of the wind wheel and the wind wheel acceleration is greater than the threshold;

[0109] The non-linear speed setting module reduces the set value of the wind wheel speed, i.e. reduces the impeller speed, to reduce the load of the wind turbine by judging the yaw error measured by the nacelle wind vane when the yaw error exceeds the yaw error threshold.

[0110] Preferably, in the gust priority pitch module, under the gust working condition, the average wind speed felt by the wind wheel reaches the cut-out wind speed in a short time from the rated wind speed, the wind wheel speed increases significantly, and the speed presents an accelerating upward trend; at this time, the wind wheel speed minus the rated speed is defined as the wind wheel speed deviation, if the product of the current wind wheel speed deviation and the wind wheel speed deviation change rate exceeds the set threshold, it is judged as the gust working condition, and an additional pitch rate is added to the pitch instruction, as follows:

[0111] First, the wind wheel speed deviation is defined as follows:

[0112]

[0113] In the formula, Δω r represents the wind wheel speed deviation; ω r represents the wind wheel speed after filtering out high-frequency noise; ω rated represents the rated speed of the wind wheel; if represents that the following is a judgment condition; else represents other cases; if the wind wheel speed ω r is higher than the rated speed of the wind wheel ω rated ​ω r is equal to the difference between the wind rotor speed and the rated wind rotor speed, i.e. ω r - ω rated , otherwise the wind rotor speed deviation Δω r is equal to 0.

[0114] Based on the wind rotor speed deviation, the wind rotor speed deviation rate of change is defined as follows:

[0115]

[0116] wherein denotes the wind rotor speed deviation rate of change; d(Δω r ) / dt denotes the derivative of the wind rotor speed deviation with respect to time t; if the wind rotor speed deviation Δω r is increasing, the wind rotor speed deviation rate of change is equal to the derivative of the wind rotor speed deviation with respect to time t, otherwise the wind rotor speed deviation rate of change is equal to 0.

[0117] Based on the wind rotor speed deviation and the wind rotor speed deviation rate of change, the priority pitch additional pitch rate is defined as follows:

[0118]

[0119] wherein δ denotes the priority pitch additional pitch rate; δ E denotes the priority pitch additional pitch rate preset value; E β denotes the maximum threshold of the product of the speed deviation and the speed deviation rate of change, which varies with the average pitch angle, the current threshold E β is obtained by looking up the current pitch angle; P e denotes the current generator measured power; k denotes the power coefficient, which is set as a parameter in the interval of 0 to 1; P rated denotes the generator rated power; and and denote the logical AND operation.

[0120] Finally, the additional pitch rate is superimposed on the pitch command as follows:

[0121]

[0122] wherein β1 denotes the pitch angle command transmitted to the blade 1 pitch system; β2 denotes the pitch angle command transmitted to the blade 2 pitch system; β3 denotes the pitch angle command transmitted to the blade 3 pitch system; denotes the pitch angle command of blade 1 output by the controller; denotes the pitch angle command of blade 2 output by the controller; denotes the pitch angle command of blade 3 output by the controller; and ∫δdt denotes the additional pitch angle integrated from the priority pitch additional pitch rate.

[0123] Preferably, in the gust overspeed inhibition module, the average wind speed experienced by the wind turbine in gust condition is from rated wind speed to cut-out wind speed in a short time, at this time the nacelle acceleration will increase obviously and the rotor speed will show an accelerating upward trend. Since the nacelle acceleration responds to the gust more quickly, the nacelle acceleration is used as a pre-judgment condition, and after a delay time, the rotor speed is monitored to see if it has an accelerating trend. If it exceeds the threshold, an additional pitch rate is superimposed on the pitch command, as follows:

[0124] The delay time is realized by a timer. When the nacelle acceleration exceeds the acceleration threshold, the timer starts timing; when the nacelle acceleration is below the acceleration threshold, the timer is initialized to zero. The timer for the nacelle acceleration as a pre-judgment condition is defined as follows:

[0125]

[0126] In the formula, t n represents the time of the timer at time n; t n-1 represents the time of the timer at time n-1; and Δt represents the time step from time n-1 to n; represents the nacelle fore-aft direction acceleration; M fa represents the nacelle fore-aft acceleration threshold; if represents the judgment condition; and else represents other cases;

[0127] Based on the timer and the rotor speed deviation change rate, the overspeed inhibition additional pitch rate is defined as follows:

[0128]

[0129] In the formula, λ represents the overspeed inhibition additional pitch rate; λ E represents the preset value of the overspeed inhibition additional pitch rate; represents the rotor speed deviation change rate; H β represents the threshold of the rotor speed deviation change rate; T E represents the time threshold of the timer; and and represents the logical and operation;

[0130] Finally, the additional pitch rate is superimposed on the pitch command, as follows:

[0131]

[0132] In the formula, β1 represents the pitch angle command transmitted to the blade 1 pitch system; β2 represents the pitch angle command transmitted to the blade 2 pitch system; and β3 represents the pitch angle command transmitted to the blade 3 pitch system; represents the pitch angle command of blade 1 output by the controller; represents the pitch angle command of blade 2 output by the controller; represents the pitch angle command of blade 3 output by the controller; ∫λdt represents the overspeed inhibition additional pitch rate integral into additional pitch angle.

[0133] Preferably, in the nonlinear speed setting module, when the yaw error angle measured by the nacelle wind vane exceeds a threshold value, the orientation of the wind wheel deviates greatly from the wind direction, at this time, the wind wheel is not directly against the wind, the wind wheel is subjected to a large unbalanced bending moment, and by reducing the rotor speed, the load on the wind wheel will be reduced simultaneously; when the wind wheel is finally yawed to be against the wind, at this time, the yaw error is reduced, and the rotor speed is restored to the rated speed operation; wherein the rotor speed setting value is defined as follows:

[0134]

[0135] In the formula, ω set represents the rotor speed setting value; ω rated represents the rated rotor speed; φ represents the yaw error angle after low-pass filtering of the yaw error measured by the nacelle wind vane; f(φ) represents the nonlinear part of the speed setting value, which is a lookup table function, and the speed setting value offset is looked up according to the yaw error angle; abs(φ) represents the absolute value of the yaw error angle; φ E represents the threshold value of the absolute value of the yaw error angle; if represents the following is a judgment condition; else represents other cases.

[0136] Embodiment 3

[0137] The embodiment discloses a storage medium, which stores a program, and when the program is executed by a processor, the load reduction control method of the wind turbine under the limit gust is realized.

[0138] The storage medium in the embodiment can be a disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), a U disk, a mobile hard disk, and the like.

[0139] Embodiment 4

[0140] The embodiment discloses a computing device, which comprises a processor and a memory for storing a program executable by the processor, and when the processor executes the program stored in the memory, the load reduction control method of the wind turbine under the limit gust is realized.

[0141] The computing device described in the embodiments can be a desktop computer, a notebook computer, a smart phone, a PDA handheld terminal, a tablet computer, a programmable logic controller (PLC), or other terminal device with processor function.

[0142] The above embodiments are preferred embodiments of the present application, but the embodiments of the present application are not limited to the above embodiments, and any changes, modifications, substitutions, combinations, simplifications, etc. made without departing from the spirit and principles of the present application should be equivalent replacement methods and should be included in the protection scope of the present application.

Claims

1. A load reduction control method for a wind turbine generator set under extreme gusts, characterized in that: include: Gust-priority pitch control: By judging the current rotor speed deviation and the rate of change of the rotor speed deviation, when it exceeds the set threshold, an additional pitch rate is superimposed on the pitch command; Gust overspeed suppression: By judging the current nacelle acceleration, when the nacelle acceleration exceeds the threshold, after a delay period, the wind rotor speed is greater than the wind rotor rated speed and the wind rotor acceleration is greater than the threshold, an additional pitch rate is superimposed on the pitch command; Non-linear speed setting: By judging the yaw error measured by the nacelle wind vane, when the yaw error exceeds the yaw error threshold, the set value of the wind rotor speed is reduced, that is, the impeller speed is reduced to reduce the load of the wind turbine; In gust-priority pitch control, when a wind turbine operates in gusty conditions, the average wind speed felt by the rotor increases from the rated wind speed to the cut-out wind speed in a short period of time. The rotor speed increases significantly, and the speed shows an accelerating upward trend. At this time, the rotor speed deviation is defined as the rotor speed minus the rated speed. If the product of the current rotor speed deviation and the rotor speed deviation change rate exceeds the set threshold, it is determined to be a gust condition, and an additional pitch rate is superimposed on the pitch control command, as follows: First, define the wind rotor speed deviation as follows: Where Δω r Indicates the wind wheel speed deviation; ω r Indicates the wind wheel speed after filtering out high-frequency noise; ω rated Indicates the rated speed of the wind wheel; if indicates the following judgment condition; else indicates other conditions; if the wind wheel speed ω r Higher than the rated speed of the wind wheelω rated When the wind wheel speed deviation Δω r Equal to the difference between the wind rotor speed and the rated speed of the wind rotor, that is, ω r -ω rated , otherwise the wind wheel speed deviation Δω r =0; Based on the wind rotor speed deviation, the wind rotor speed deviation change rate is defined as follows: Where, Indicates the rate of change of the wind wheel speed deviation; d(Δω r ) / dt represents the derivative of the rotor speed deviation with respect to time t; if the rotor speed deviation Δω r When accelerating upward, the wind wheel speed deviation change rate Equal to the derivative of the wind rotor speed deviation with respect to time t, otherwise the rate of change of the wind rotor speed deviation is equal to 0; Based on the rotor speed deviation and the rotor speed deviation change rate, the priority pitch additional pitch rate is defined as follows: Where, δ represents the priority pitch additional pitch rate; δ E Indicates the priority pitch additional pitch rate preset value; E β It represents the maximum threshold of the product of the speed deviation and the speed deviation change rate. This threshold changes with the change of the average pitch angle. e Indicates the current generator measured power; k represents the power coefficient, and the parameter is set in the range of 0 to 1; P rated Indicates the rated power of the generator; and indicates the logical AND operation; Finally, the additional pitch rate is added to the pitch command as follows: Where β1 represents the pitch angle command transmitted to the pitch system of blade 1; β2 represents the pitch angle command transmitted to the pitch system of blade 2; β3 represents the pitch angle command transmitted to the pitch system of blade 3; represents the pitch angle command of blade 1 output by the controller; represents the pitch angle command of blade 2 output by the controller; represents the pitch angle command of blade 3 output by the controller; ∫δdt represents the priority pitch additional pitch rate integrated into the additional pitch angle; In gust overspeed suppression, when a wind turbine is operating under gusty conditions, the average wind speed felt by the rotor increases from the rated wind speed to the cut-out wind speed in a short period of time. At this time, the nacelle acceleration will increase significantly, and the speed will show an accelerating upward trend. Since the nacelle acceleration responds more quickly to gusts, the nacelle acceleration is used as a pre-judgment condition. After a delay time, the rotor speed is monitored to see if there is an acceleration trend. If the threshold is exceeded, an additional pitch rate is superimposed on the pitch command, as follows: The delay time is implemented by a timer. When the cabin acceleration exceeds the acceleration threshold, the timer starts counting; when the cabin acceleration falls below the acceleration threshold, the timer is initialized to zero. The timer for cabin acceleration as a pre-judgment condition is defined as follows: Where, t n Indicates the time of the timer at time n; t n-1 represents the time of the timer at time n-1; Δt represents the time step from time n-1 to time n; Indicates the acceleration in the longitudinal direction of the cabin; M fa Indicates the acceleration threshold for the front and rear of the cabin; if indicates the following judgment condition; else indicates other conditions; Based on the timer and the rotor speed deviation change rate, the overspeed suppression additional pitch rate is defined as follows: Where, λ represents the additional pitch rate for overspeed suppression; λ E Indicates the preset value of the additional pitch rate for overspeed suppression; Indicates the rate of change of the wind wheel speed deviation; H β Indicates the wind wheel speed deviation change rate threshold; T E Indicates the time threshold of the timer; and indicates the logical AND operation; Finally, the additional pitch rate is added to the pitch command as follows: Where β1 represents the pitch angle command transmitted to the pitch system of blade 1; β2 represents the pitch angle command transmitted to the pitch system of blade 2; β3 represents the pitch angle command transmitted to the pitch system of blade 3; represents the pitch angle command of blade 1 output by the controller; represents the pitch angle command of blade 2 output by the controller; represents the pitch angle command of blade 3 output by the controller; ∫λdt represents the overspeed suppression additional pitch rate integrated into the additional pitch angle; In the nonlinear speed setting, when the nacelle wind vane instrument measures a yaw error angle exceeding a threshold, the rotor's orientation deviates significantly from the wind direction. At this point, the rotor is not facing the wind and is subject to a large unbalanced bending moment. By reducing the rotor speed, the load on the rotor is reduced simultaneously. When the rotor finally yaws into the wind, the yaw error decreases and the rotor speed returns to the rated speed. The rotor speed setting value is defined as follows: Where, ω set Indicates the impeller speed setting value; ω rated represents the rated speed of the impeller; φ represents the yaw error angle after low-pass filtering of the yaw error measured by the cabin wind vane; f(φ) represents the nonlinear part of the speed setting value, which is a lookup function that looks up the speed setting value offset according to the yaw error angle; abs(φ) represents the absolute value of the yaw error angle; φ E Indicates the threshold of the absolute value of the yaw error angle; if indicates that the following is a judgment condition; else indicates other situations.

2. A load reduction control system for a wind turbine under extreme gusts, characterized in that: include: The gust-priority pitch control module determines the current rotor speed deviation and the rate of change of the rotor speed deviation. When the deviation exceeds the set threshold, it adds an additional pitch rate to the pitch control instruction. The gust overspeed suppression module judges the current nacelle acceleration. When the nacelle acceleration exceeds the threshold, after a delay period, the wind rotor speed is greater than the rated speed of the wind rotor and the wind rotor acceleration is greater than the threshold, an additional pitch rate is superimposed on the pitch command; The nonlinear speed setting module judges the yaw error measured by the nacelle wind vane. When the yaw error exceeds the yaw error threshold, the set value of the wind rotor speed is reduced, that is, the impeller speed is reduced to reduce the load of the wind turbine; In the gust-priority pitch control module, when a wind turbine operates in gusty conditions, the average wind speed felt by the rotor increases from the rated wind speed to the cut-out wind speed in a short period of time, causing the rotor speed to increase significantly, and the speed to show an accelerating upward trend. At this time, the rotor speed deviation is defined as the rotor speed minus the rated speed. If the product of the current rotor speed deviation and the rotor speed deviation change rate exceeds the set threshold, it is determined to be a gust condition, and an additional pitch rate is superimposed on the pitch control command, as follows: First, define the wind rotor speed deviation as follows: Where Δω r Indicates the wind wheel speed deviation; ω r Indicates the wind wheel speed after filtering out high-frequency noise; ω rated Indicates the rated speed of the wind wheel; if indicates the following judgment condition; else indicates other conditions; if the wind wheel speed ω r Higher than the rated speed of the wind wheelω rated When the wind wheel speed deviation Δω r Equal to the difference between the wind rotor speed and the rated speed of the wind rotor, that is, ω r -ω rated , otherwise the wind wheel speed deviation Δω r =0; Based on the wind rotor speed deviation, the wind rotor speed deviation change rate is defined as follows: Where, Indicates the rate of change of the wind wheel speed deviation; d(Δω r ) / dt represents the derivative of the rotor speed deviation with respect to time t; if the rotor speed deviation Δω r When accelerating upward, the wind wheel speed deviation change rate Equal to the derivative of the wind rotor speed deviation with respect to time t, otherwise the rate of change of the wind rotor speed deviation is equal to 0; Based on the rotor speed deviation and the rotor speed deviation change rate, the priority pitch additional pitch rate is defined as follows: Where, δ represents the priority pitch additional pitch rate; δ E Indicates the priority pitch additional pitch rate preset value; E β It represents the maximum threshold of the product of the speed deviation and the speed deviation change rate. This threshold changes with the change of the average pitch angle. e Indicates the current generator measured power; k represents the power coefficient, and the parameter is set in the range of 0 to 1; P rated Indicates the rated power of the generator; and indicates the logical AND operation; Finally, the additional pitch rate is added to the pitch command as follows: Where β1 represents the pitch angle command transmitted to the pitch system of blade 1; β2 represents the pitch angle command transmitted to the pitch system of blade 2; β3 represents the pitch angle command transmitted to the pitch system of blade 3; represents the pitch angle command of blade 1 output by the controller; represents the pitch angle command of blade 2 output by the controller; represents the pitch angle command of blade 3 output by the controller; ∫δdt represents the priority pitch additional pitch rate integrated into the additional pitch angle; In the gust overspeed suppression module, when the wind turbine is in gusty conditions, the average wind speed felt by the rotor reaches the cut-out wind speed from the rated wind speed in a short period of time. At this time, the nacelle acceleration will increase significantly, and the speed will show an accelerating upward trend. Since the nacelle acceleration responds more quickly to gusts, the nacelle acceleration is used as a pre-judgment condition. After a delay time, the rotor speed is monitored to see if there is an acceleration trend. If it exceeds the threshold, an additional pitch rate is superimposed on the pitch command, as follows: The delay time is implemented by a timer. When the cabin acceleration exceeds the acceleration threshold, the timer starts counting; when the cabin acceleration falls below the acceleration threshold, the timer is initialized to zero. The timer for cabin acceleration as a pre-judgment condition is defined as follows: Where, t n Indicates the time of the timer at time n; t n-1 represents the time of the timer at time n-1; Δt represents the time step from time n-1 to time n; Indicates the acceleration in the longitudinal direction of the cabin; M fa Indicates the acceleration threshold for the front and rear of the cabin; if indicates the following judgment condition; else indicates other conditions; Based on the timer and the rotor speed deviation change rate, the overspeed suppression additional pitch rate is defined as follows: Where, λ represents the additional pitch rate for overspeed suppression; λ E Indicates the preset value of the additional pitch rate for overspeed suppression; Indicates the rate of change of the wind wheel speed deviation; H β Indicates the wind wheel speed deviation change rate threshold; T E Indicates the time threshold of the timer; and indicates the logical AND operation; Finally, the additional pitch rate is added to the pitch command as follows: Where β1 represents the pitch angle command transmitted to the pitch system of blade 1; β2 represents the pitch angle command transmitted to the pitch system of blade 2; β3 represents the pitch angle command transmitted to the pitch system of blade 3; represents the pitch angle command of blade 1 output by the controller; represents the pitch angle command of blade 2 output by the controller; represents the pitch angle command of blade 3 output by the controller; ∫λdt represents the overspeed suppression additional pitch rate integrated into the additional pitch angle; In the nonlinear speed setting module, when the nacelle wind vane measures a yaw error angle exceeding a threshold, the rotor's orientation deviates significantly from the wind direction. At this point, the rotor is not facing the wind and is subject to a large unbalanced bending moment. By reducing the rotor speed, the load on the rotor is reduced. When the rotor finally yaws into the wind, the yaw error decreases and the rotor speed returns to the rated speed. The rotor speed setting value is defined as follows: Where, ω set Indicates the impeller speed setting value; ω rated represents the rated speed of the impeller; φ represents the yaw error angle after low-pass filtering of the yaw error measured by the cabin wind vane; f(φ) represents the nonlinear part of the speed setting value, which is a lookup function that looks up the speed setting value offset according to the yaw error angle; abs(φ) represents the absolute value of the yaw error angle; φ E Indicates the threshold of the absolute value of the yaw error angle; if indicates that the following is a judgment condition; else indicates other situations.

3. A storage medium storing a program, characterized in that: When the program is executed by the processor, the load reduction control method for the wind turbine generator set under extreme gusts according to claim 1 is implemented.

4. A computing device comprising a processor and a memory for storing a program executable by the processor, characterized in that When the processor executes the program stored in the memory, the load reduction control method for the wind turbine generator set under extreme gusts according to claim 1 is implemented.

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