阅读说明：本技术 一种解决风力发电机组塔架净空问题的控制方法与模块 (Control method and module for solving clearance problem of tower of wind generating set ) 是由 周玲 任永 邹荔兵 王超 卢军 王伟 张广兴 于 2020-12-22 设计创作，主要内容包括：本发明公开了一种解决风力发电机组塔架净空问题的控制方法与模块,通过监测塔架倾覆弯矩变化率以及机组的实时功率和桨距角,再分别与各自限定值进行对比,判断机组是否处于极端负剪切风况,若判断机组不处于极端负剪切风况下,则各叶片采用统一变桨控制策略,即采用机组的变桨控制器输出的原始变桨指令,一旦判断机组是处于极端负剪切风况下,则启动基于叶轮方位角的独立变桨IPC控制策略,通过计算不同叶片所需的不同额外桨距角补偿到对应的叶片上,减小机组受力,即叶片受力,从而减小叶片形变量和位移,增大叶尖到塔架表面的最小距离,从而解决风力发电机组塔架净空问题,保障风力发电机组安全稳定运行。(The invention discloses a control method and a module for solving the clearance problem of a tower of a wind generating set, which judge whether the set is in an extreme negative shearing wind condition or not by monitoring the change rate of the overturning bending moment of the tower and the real-time power and the pitch angle of the set and respectively comparing the change rate with respective limit values, if the set is judged not to be in the extreme negative shearing wind condition, each blade adopts a unified pitch control strategy, namely, an original pitch instruction output by a pitch controller of the set is adopted, once the set is judged to be in the extreme negative shearing wind condition, an independent pitch IPC control strategy based on the azimuth angle of an impeller is started, different extra pitch angles required by different blades are calculated to be compensated to the corresponding blades, the stress of the set, namely the stress of the blades is reduced, so that the deformation and displacement of the blades are reduced, the minimum distance of wind power from the blade tips to the surface of the tower is, the safe and stable operation of the wind generating set is guaranteed.)

1. A control method for solving the problem of clearance of a tower of a wind generating set is characterized in that the method comprises the steps of monitoring the change rate of the overturning bending moment of the tower and the real-time power and the pitch angle of a unit, comparing the change rate with respective limit values, judging whether the unit is in an extreme negative shear wind condition, if the unit is not in the extreme negative shear wind condition, adopting a unified pitch control strategy for each blade, namely adopting an original pitch instruction output by a pitch controller of the unit, and starting an independent pitch control IPC strategy based on an impeller azimuth angle once the unit is judged to be in the extreme negative shear wind condition: increasing or decreasing the pitch angle according to different azimuth angles of the blades, reducing unbalanced stress of the blades, namely reducing a pitch angle at the azimuth angle of 0 degree, increasing forward thrust of the blades at the azimuth angle of 0 degree, increasing the pitch angle at the azimuth angle of 180 degrees, reducing the forward thrust of the blades at the azimuth angle of 180 degrees, reducing a tower overturning bending moment introduced by the unbalanced thrust, reducing a blade deformation quantity, and reducing the power fluctuation caused by the advanced pitch because the blade clearance problem only occurs when the blades are close to the tower and are near the azimuth angle of 180 degrees, so that the blades are pitched in advance before reaching the azimuth angle of 180 degrees, the blade deformation is reduced, the pitch angles of the other two blades need to be properly compensated to achieve the purpose of constant power, and finally, different extra pitch angles required by different blades are calculated to be compensated to the corresponding blades, so as to reduce the stress of a unit, the blades are stressed, so that the deformation quantity and displacement of the blades are reduced, the minimum distance from the blade tips to the surface of the tower is increased, the problem of tower clearance of the wind generating set is solved, and the safe and stable operation of the wind generating set is guaranteed.

2. A control method for solving the problem of tower clearance of a wind generating set according to claim 1, comprising the following steps:

1) calculating the change rate of the overturning bending moment of the tower;

measuring the tower overturning bending moment value, and calculating the tower overturning bending moment change rate through a second-order low-pass filterThe following formula is used:

M_yf(k)＝M_y(k)*F(s)

M_yf(k-1)＝M_y(k-1)*F(s)

wherein F(s) is a second-order low-pass filter transfer function, ξ is a damping coefficient, ω is a frequency, s is a Laplace operator, k represents the current time, M is a frequency, and_y(k) is the tower overturning moment value at the current moment, M_yf(k) Is the value of the tower overturning bending moment at the current moment after being filtered, k-1 represents the previous moment, M_y(k-1) is the tower overturning moment value at the previous moment, M_yf(k-1) is the value of the tower overturning bending moment at the previous moment after filtering, and T is sampling time;

2) real-time power P of measuring unit_tAnd a real-time pitch angle;

3) judging whether an independent pitch control IPC strategy is started or not;

three conditions must be met simultaneously for starting the independent pitch IPC control strategy: firstly, the change rate of the tower overturning bending moment is not less than the limit value of the change rate of the tower overturning bending moment; secondly, the real-time power is not less than the power limit value; thirdly, the real-time pitch angle is not greater than the pitch angle limit value; the method comprises the following specific steps:

wherein F is the limiting value of the change rate of the tower overturning bending moment, P_FIs a power limit value, pitch_FIs a pitch angle limit;

if the three conditions are met, starting an independent pitch control IPC strategy, and executing steps 4) -7); if any one of the conditions is not met, the independent pitch control IPC strategy is not started, and each blade adopts a unified pitch control strategy, namely an original pitch instruction output by a pitch controller;

4) measuring and calculating an impeller azimuth angle;

measuring the azimuth angle of the blade 1, calculating the azimuth angles of the blade 2 and the blade 3 according to the fact that the three blades are uniformly distributed on an impeller plane, defining the vertical upward azimuth angle of the blade to be 0 degree, measuring through a sensor to obtain the azimuth angle of the blade 1 to be alpha, and adding the azimuth angle of the blade 2 on the basis of the azimuth angle of the blade 1The azimuth angle of the blade 3 is added on the basis of the azimuth angle of the blade 1Namely:

RotorAzimuth1＝α

wherein RotorAzimuth1 is the azimuth of blade 1, RotorAzimuth2 is the azimuth of blade 2, and RotorAzimuth3 is the azimuth of blade 3;

5) calculating an extra pitch angle compensation value of each blade;

an independent variable pitch IPC control strategy based on an impeller azimuth angle introduces a cosine function for calculating an extra pitch angle compensation value, gives an amplitude Azimuth IPCAmplite which is defined as A, and adds an angle RotorAzimuth Advance to the measured impeller azimuth angle which is defined as beta in consideration of the hysteresis of a variable pitch system of a unit, so that the effect of advance action is achieved, namely:

AzimuthIPCAmplitude＝A

RotorAzimuthAdvance＝β

Δpitchangle1＝-A*cos(α+β)

in the formula, Δ pitch 1 is the extra pitch angle compensation value of blade 1, Δ pitch 2 is the extra pitch angle compensation value of blade 2, and Δ pitch 3 is the extra pitch angle compensation value of blade 3;

6) calculating a given value of a pitch angle of each blade, namely a given value of a pitch instruction;

the given value of the variable pitch instruction is equal to the original variable pitch instruction pitch output by the variable pitch controller_originalThe extra pitch angle compensation value is superimposed, i.e.:

pitch_demand1＝pitch_original+Δpitchangle1

pitch_demand2＝pitch_original+Δpitchangle2

pitch_demand3＝pitch_original+Δpitchangle3

in the formula, pitch_demand1Setting a pitch instruction given value for the blade 1_demand2For setting the pitch command values of the blades 2, pitch_demand3Setting a given value for a variable pitch instruction of the blade 3;

the variable pitch controller obtains a final variable pitch instruction according to the variable pitch instruction set value of each blade;

7) executing pitch angle variation;

the variable pitch actuator of the unit adjusts the pitch angle of each blade according to a final variable pitch instruction sent by the variable pitch controller, so that the constant power can be ensured while the deformation of the blade is reduced when the blade approaches the tower, and the problem of clearance of the tower of the wind generating set is solved.

3. The control method for solving the problem of tower clearance of the wind generating set according to claim 2, wherein in the step 3), P is_FTaking 0.7 times of rated power, pitch_FTake 4 °.

4. The utility model provides a solve control module of wind generating set pylon headroom problem, a serial communication port, this module is through monitoring the real-time power and the pitch angle of pylon overturning moment of flexure change rate and unit, the limiting value of each is again respectively contrasted, judge whether the unit is in extreme negative shear wind condition, if judge the unit not be in extreme negative shear wind condition, then each blade adopts the unified oar control strategy that becomes, adopt the original oar instruction that becomes of the oar controller output of unit promptly, in case judge the unit be in extreme negative shear wind condition, then start the independent oar IPC control strategy that becomes based on the impeller azimuth: increasing or decreasing the pitch angle according to different azimuth angles of the blades, reducing unbalanced stress of the blades, namely reducing a pitch angle at the azimuth angle of 0 degree, increasing forward thrust of the blades at the azimuth angle of 0 degree, increasing the pitch angle at the azimuth angle of 180 degrees, reducing the forward thrust of the blades at the azimuth angle of 180 degrees, reducing a tower overturning bending moment introduced by the unbalanced thrust, reducing a blade deformation quantity, and reducing the power fluctuation caused by the advanced pitch because the blade clearance problem only occurs when the blades are close to the tower and are near the azimuth angle of 180 degrees, so that the blades are pitched in advance before reaching the azimuth angle of 180 degrees, the blade deformation is reduced, the pitch angles of the other two blades need to be properly compensated to achieve the purpose of constant power, and finally, different extra pitch angles required by different blades are calculated to be compensated to the corresponding blades, so as to reduce the stress of a unit, the blades are stressed, so that the deformation quantity and displacement of the blades are reduced, the minimum distance from the blade tips to the surface of the tower is increased, the problem of tower clearance of the wind generating set is solved, and the safe and stable operation of the wind generating set is guaranteed.

5. The control module of claim 4, wherein the control module is configured to solve the problem of tower clearance of the wind turbine generator system, and comprises:

the tower overturning bending moment change rate calculation unit is used for calculating the tower overturning bending moment change rate;

a real-time power and pitch angle measuring unit for measuring the real-time power P of the unit_tAnd a real-time pitch angle;

the judging unit is used for judging whether the unit is under the extreme negative shear wind condition or not, if the unit is not under the extreme negative shear wind condition, a unified variable pitch control strategy is adopted by each blade, namely, an original variable pitch instruction output by a variable pitch controller of the unit is adopted, and once the unit is judged to be under the extreme negative shear wind condition, an independent variable pitch IPC control strategy based on an impeller azimuth angle is started;

and the independent variable pitch IPC control strategy execution unit is used for calculating an impeller azimuth angle and an extra pitch angle compensation value of each blade, further calculating a given value of each blade pitch angle to obtain a final variable pitch instruction, and sending the final variable pitch instruction to a variable pitch actuator of the unit through a variable pitch controller to execute adjustment of each blade pitch angle, so that the power can be ensured to be constant while the blade deformation is reduced when the blade approaches a tower, and the problem of tower clearance of a wind generating set is solved.

6. The control module of claim 5, wherein the tower overturning bending moment rate of change calculating unit calculates the tower overturning bending moment rate of change by measuring the tower overturning bending moment value and passing through a second-order low-pass filterBy usingThe following equation:

M_yf(k)＝M_y(k)*F(s)

M_yf(k-1)＝M_y(k-1)*F(s)

wherein F(s) is a second-order low-pass filter transfer function, ξ is a damping coefficient, ω is a frequency, s is a Laplace operator, k represents the current time, M is a frequency, and_y(k) is the tower overturning moment value at the current moment, M_yf(k) Is the value of the tower overturning bending moment at the current moment after being filtered, k-1 represents the previous moment, M_y(k-1) is the tower overturning moment value at the previous moment, M_yfAnd (k-1) is the value of the tower overturning bending moment at the previous moment after filtering, and T is sampling time.

7. The control module for solving the problem of tower clearance of the wind generating set according to claim 5, wherein in the judging unit, three conditions must be satisfied simultaneously when the independent pitch control strategy is started: firstly, the change rate of the tower overturning bending moment is not less than the limit value of the change rate of the tower overturning bending moment; secondly, the real-time power is not less than the power limit value; thirdly, the real-time pitch angle is not greater than the pitch angle limit value; the method comprises the following specific steps:

wherein F is the limiting value of the change rate of the tower overturning bending moment, P_FIs a power limit value, pitch_FIs a pitch angle limit;

if the three conditions are met, starting an independent pitch control IPC strategy; and if any one of the conditions is not met, the independent pitch control IPC strategy is not started.

8. The control module for solving the clearance problem of the tower of the wind generating set according to claim 5, wherein in the independent pitch IPC control strategy execution unit, the azimuth angle of the blade 1 is measured, the azimuth angles of the blade 2 and the blade 3 are calculated according to the fact that the three blades are uniformly distributed in an impeller plane, the azimuth angle of the blade in the vertical direction is defined to be 0 degree, the azimuth angle of the blade 1 is measured by the sensor to be alpha, and the azimuth angle of the blade 2 is added on the basis of the azimuth angle of the blade 1The azimuth angle of the blade 3 is added on the basis of the azimuth angle of the blade 1Namely:

RotorAzimuth1＝α

wherein RotorAzimuth1 is the azimuth of blade 1, RotorAzimuth2 is the azimuth of blade 2, and RotorAzimuth3 is the azimuth of blade 3;

an independent variable pitch IPC control strategy based on an impeller azimuth angle introduces a cosine function for calculating an extra pitch angle compensation value, gives an amplitude Azimuth IPCAmplite which is defined as A, and adds an angle RotorAzimuth Advance to the measured impeller azimuth angle which is defined as beta in consideration of the hysteresis of a variable pitch system of a unit, so that the effect of advance action is achieved, namely:

AzimuthIPCAmplitude＝A

RotorAzimuthAdvance＝β

Δpitchangle1＝-A*cos(α+β)

in the formula, Δ pitch 1 is the extra pitch angle compensation value of blade 1, Δ pitch 2 is the extra pitch angle compensation value of blade 2, and Δ pitch 3 is the extra pitch angle compensation value of blade 3;

the given value of the pitch angle of each blade, namely the given value of the variable pitch instruction, is equal to the original variable pitch instruction pitch output by the variable pitch controller_originalSuperimposing the respective extra pitch angle compensation values, i.e.:

pitch_demand1＝pitch_original+Δpitchangle1

pitch_demand2＝pitch_original+Δpitchangle2

pitch_demand3＝pitch_original+Δpitchangle3

in the formula, pitch_demand1Setting a pitch instruction given value for the blade 1_demand2For setting the pitch command values of the blades 2, pitch_demand3Setting a given value for a variable pitch instruction of the blade 3;

and the variable pitch controller obtains a final variable pitch instruction according to the variable pitch instruction set value of each blade, and sends the final variable pitch instruction to the variable pitch actuator for execution.

Technical Field

The invention relates to the technical field of wind generating sets, in particular to a control method and a control module for solving the problem of tower clearance of a wind generating set.

Background

With the development of wind power generation technology, the capacity of a wind generating set is larger and larger, blades are longer and longer, and a tower is higher and higher, and the wind generating set is often operated in a relatively severe external environment, which causes the load of the wind generating set to be larger and larger in the operation process, the deformation of the blades is also large, the problem of tower clearance is directly serious, and great challenges are formed on the design and operation of the wind generating set. In addition, the blade-sweeping tower may cause tower collapse, which results in complete machine damage, and thus once the blade-sweeping tower occurs, great economic loss is brought to the wind power plant.

The tower clearance of a wind turbine is the distance from the tip of the blade to the tower surface during rotation of the impeller. The blade is an important device for converting wind energy into electric energy, and the tower is a main bearing mechanism of the wind generating set, so that the wind generating set is ensured to operate stably, and the problem of tower clearance is particularly important.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides a control method for solving the problem of tower clearance of a wind generating set, reduces the deformation of blades when the blades are close to the tower, and ensures that the power is basically constant, so that the set can stably run.

The second purpose of the invention is to provide a control module for solving the problem of tower clearance of the wind generating set.

The first purpose of the invention is realized by the following technical scheme: a control method for solving the clearance problem of a tower of a wind generating set comprises the steps of monitoring the change rate of the overturning bending moment of the tower and the real-time power and the pitch angle of a unit, comparing the change rate with respective limit values, judging whether the unit is in an extreme negative shearing wind condition, if the unit is not in the extreme negative shearing wind condition, adopting a unified pitch control strategy for each blade, namely adopting an original pitch instruction output by a pitch controller of the unit, and starting an independent pitch IPC control strategy based on the azimuth angle of an impeller once the unit is judged to be in the extreme negative shearing wind condition: increasing or decreasing the pitch angle according to different azimuth angles of the blades, reducing unbalanced stress of the blades, namely reducing a pitch angle at the azimuth angle of 0 degree, increasing forward thrust of the blades at the azimuth angle of 0 degree, increasing the pitch angle at the azimuth angle of 180 degrees, reducing the forward thrust of the blades at the azimuth angle of 180 degrees, reducing a tower overturning bending moment introduced by the unbalanced thrust, reducing a blade deformation quantity, and reducing the power fluctuation caused by the advanced pitch because the blade clearance problem only occurs when the blades are close to the tower and are near the azimuth angle of 180 degrees, so that the blades are pitched in advance before reaching the azimuth angle of 180 degrees, the blade deformation is reduced, the pitch angles of the other two blades need to be properly compensated to achieve the purpose of constant power, and finally, different extra pitch angles required by different blades are calculated to be compensated to the corresponding blades, so as to reduce the stress of a unit, the blades are stressed, so that the deformation quantity and displacement of the blades are reduced, the minimum distance from the blade tips to the surface of the tower is increased, the problem of tower clearance of the wind generating set is solved, and the safe and stable operation of the wind generating set is guaranteed.

The control method for solving the problem of tower clearance of the wind generating set comprises the following steps:

1) calculating the change rate of the overturning bending moment of the tower;

measuring the tower overturning bending moment value, and calculating the tower overturning bending moment change rate through a second-order low-pass filterThe following formula is used:

M_yf(k)＝M_y(k)*F(s)

M_yf(k-1)＝M_y(k-1)*F(s)

wherein F(s) is a second-order low-pass filter transfer function, ξ is a damping coefficient, ω is a frequency, s is a Laplace operator, k represents the current time, M is a frequency, and_y(k) is the tower overturning moment value at the current moment, M_yf(k) Is the value of the tower overturning bending moment at the current moment after being filtered, k-1 represents the previous moment, M_y(k-1) is the tower overturning moment value at the previous moment, M_yf(k-1) is the value of the tower overturning bending moment at the previous moment after filtering, and T is sampling time;

2) real-time power P of measuring unit_tAnd a real-time pitch angle;

3) judging whether an independent pitch control IPC strategy is started or not;

three conditions must be met simultaneously for starting the independent pitch IPC control strategy: firstly, the change rate of the tower overturning bending moment is not less than the limit value of the change rate of the tower overturning bending moment; secondly, the real-time power is not less than the power limit value; thirdly, the real-time pitch angle is not greater than the pitch angle limit value; the method comprises the following specific steps:

wherein F is the limiting value of the change rate of the tower overturning bending moment, P_FIs a power limit value, pitch_FIs a pitch angle limit;

if the three conditions are met, starting an independent pitch control IPC strategy, and executing steps 4) -7); if any one of the conditions is not met, the independent pitch control IPC strategy is not started, and each blade adopts a unified pitch control strategy, namely an original pitch instruction output by a pitch controller;

4) measuring and calculating an impeller azimuth angle;

measuring the azimuth angle of the blade 1, calculating the azimuth angles of the blade 2 and the blade 3 according to the fact that the three blades are uniformly distributed on an impeller plane, defining the vertical upward azimuth angle of the blade to be 0 degree, measuring through a sensor to obtain the azimuth angle of the blade 1 to be alpha, and adding the azimuth angle of the blade 2 on the basis of the azimuth angle of the blade 1The azimuth angle of the blade 3 is added on the basis of the azimuth angle of the blade 1Namely:

RotorAzimuth1＝α

wherein RotorAzimuth1 is the azimuth of blade 1, RotorAzimuth2 is the azimuth of blade 2, and RotorAzimuth3 is the azimuth of blade 3;

5) calculating an extra pitch angle compensation value of each blade;

an independent variable pitch IPC control strategy based on an impeller azimuth angle introduces a cosine function for calculating an extra pitch angle compensation value, gives an amplitude Azimuth IPCAmplite which is defined as A, and adds an angle RotorAzimuth Advance to the measured impeller azimuth angle which is defined as beta in consideration of the hysteresis of a variable pitch system of a unit, so that the effect of advance action is achieved, namely:

AzimuthIPCAmplitude＝A

RotorAzimuthAdvance＝β

Δpitchangle1＝-A*cos(α+β)

in the formula, Δ pitch 1 is the extra pitch angle compensation value of blade 1, Δ pitch 2 is the extra pitch angle compensation value of blade 2, and Δ pitch 3 is the extra pitch angle compensation value of blade 3;

6) calculating a given value of a pitch angle of each blade, namely a given value of a pitch instruction;

the given value of the variable pitch instruction is equal to the original variable pitch instruction pitch output by the variable pitch controller_originalThe extra pitch angle compensation value is superimposed, i.e.:

pitch_demand1＝pitch_original+Δpitchangle1

pitch_demand2＝pitch_original+Δpitchangle2

pitch_demand3＝pitch_original+Δpitchangle3

in the formula, pitch_demand1Setting a pitch instruction given value for the blade 1_demand2For setting the pitch command values of the blades 2, pitch_demand3Setting a given value for a variable pitch instruction of the blade 3;

the variable pitch controller obtains a final variable pitch instruction according to the variable pitch instruction set value of each blade;

7) executing pitch angle variation;

the variable pitch actuator of the unit adjusts the pitch angle of each blade according to a final variable pitch instruction sent by the variable pitch controller, so that the constant power can be ensured while the deformation of the blade is reduced when the blade approaches the tower, and the problem of clearance of the tower of the wind generating set is solved.

In step 3), P_FTaking 0.7 times of rated power, pitch_FTake 4 °.

The second purpose of the invention is realized by the following technical scheme: the utility model provides a solve control module of wind generating set pylon headroom problem, this module is through monitoring the real-time power and the pitch angle of pylon overturning moment of flexure change rate and unit, the reexamination compares with limit value separately, judge whether the unit is in extreme negative shear wind condition, if judge that the unit is not in under extreme negative shear wind condition, then each blade adopts the unified oar control strategy that becomes, adopt the original oar instruction that becomes of the oar controller output of unit promptly, in case judge that the unit is in under extreme negative shear wind condition, then start the independent oar IPC control strategy that becomes based on the impeller azimuth: increasing or decreasing the pitch angle according to different azimuth angles of the blades, reducing unbalanced stress of the blades, namely reducing a pitch angle at the azimuth angle of 0 degree, increasing forward thrust of the blades at the azimuth angle of 0 degree, increasing the pitch angle at the azimuth angle of 180 degrees, reducing the forward thrust of the blades at the azimuth angle of 180 degrees, reducing a tower overturning bending moment introduced by the unbalanced thrust, reducing a blade deformation quantity, and reducing the power fluctuation caused by the advanced pitch because the blade clearance problem only occurs when the blades are close to the tower and are near the azimuth angle of 180 degrees, so that the blades are pitched in advance before reaching the azimuth angle of 180 degrees, the blade deformation is reduced, the pitch angles of the other two blades need to be properly compensated to achieve the purpose of constant power, and finally, different extra pitch angles required by different blades are calculated to be compensated to the corresponding blades, so as to reduce the stress of a unit, the blades are stressed, so that the deformation quantity and displacement of the blades are reduced, the minimum distance from the blade tips to the surface of the tower is increased, the problem of tower clearance of the wind generating set is solved, and the safe and stable operation of the wind generating set is guaranteed.

The control module for the wind generating set tower clearance problem comprises:

the tower overturning bending moment change rate calculation unit is used for calculating the tower overturning bending moment change rate;

a real-time power and pitch angle measuring unit for measuring the real-time power P of the unit_tAnd a real-time pitch angle;

the judging unit is used for judging whether the unit is under the extreme negative shear wind condition or not, if the unit is not under the extreme negative shear wind condition, a unified variable pitch control strategy is adopted by each blade, namely, an original variable pitch instruction output by a variable pitch controller of the unit is adopted, and once the unit is judged to be under the extreme negative shear wind condition, an independent variable pitch IPC control strategy based on an impeller azimuth angle is started;

and the independent variable pitch IPC control strategy execution unit is used for calculating an impeller azimuth angle and an extra pitch angle compensation value of each blade, further calculating a given value of each blade pitch angle to obtain a final variable pitch instruction, and sending the final variable pitch instruction to a variable pitch actuator of the unit through a variable pitch controller to execute adjustment of each blade pitch angle, so that the power can be ensured to be constant while the blade deformation is reduced when the blade approaches a tower, and the problem of tower clearance of a wind generating set is solved.

Further, in the tower overturning bending moment change rate calculation unit, the tower overturning bending moment change rate is calculated by measuring the tower overturning bending moment value and passing through a second-order low-pass filterThe following formula is used:

M_yf(k)＝M_y(k)*F(s)

M_yf(k-1)＝M_y(k-1)*F(s)

wherein F(s) is a second-order low-pass filter transfer function, ξ is a damping coefficient, ω is a frequency, s is a Laplace operator, k represents the current time, M is a frequency, and_y(k) is the tower overturning moment value at the current moment, M_yf(k) Is the value of the tower overturning bending moment at the current moment after being filtered, k-1 represents the previous moment, M_y(k-1) is the tower overturning moment value at the previous moment，M_yfAnd (k-1) is the value of the tower overturning bending moment at the previous moment after filtering, and T is sampling time.

Further, in the determination unit, the starting of the independent pitch control IPC control strategy must satisfy three conditions at the same time: firstly, the change rate of the tower overturning bending moment is not less than the limit value of the change rate of the tower overturning bending moment; secondly, the real-time power is not less than the power limit value; thirdly, the real-time pitch angle is not greater than the pitch angle limit value; the method comprises the following specific steps:

wherein F is the limiting value of the change rate of the tower overturning bending moment, P_FIs a power limit value, pitch_FIs a pitch angle limit;

if the three conditions are met, starting an independent pitch control IPC strategy; and if any one of the conditions is not met, the independent pitch control IPC strategy is not started.

Further, in the independent pitch control IPC control strategy execution unit, the azimuth angle of the blade 1 is measured, the azimuth angles of the blade 2 and the blade 3 are calculated according to the fact that the three blades are uniformly distributed on an impeller plane, the vertical upward azimuth angle of the blade is defined to be 0 degrees, the azimuth angle of the blade 1 is measured to be alpha through a sensor, and then the azimuth angle of the blade 2 is added to the azimuth angle of the blade 1The azimuth angle of the blade 3 is added on the basis of the azimuth angle of the blade 1Namely:

RotorAzimuth1＝α

wherein RotorAzimuth1 is the azimuth of blade 1, RotorAzimuth2 is the azimuth of blade 2, and RotorAzimuth3 is the azimuth of blade 3;

an independent variable pitch IPC control strategy based on an impeller azimuth angle introduces a cosine function for calculating an extra pitch angle compensation value, gives an amplitude Azimuth IPCAmplite which is defined as A, and adds an angle RotorAzimuth Advance to the measured impeller azimuth angle which is defined as beta in consideration of the hysteresis of a variable pitch system of a unit, so that the effect of advance action is achieved, namely:

AzimuthIPCAmplitude＝A

RotorAzimuthAdvance＝β

Δpitchangle1＝-A*cos(α+β)

in the formula, Δ pitch 1 is the extra pitch angle compensation value of blade 1, Δ pitch 2 is the extra pitch angle compensation value of blade 2, and Δ pitch 3 is the extra pitch angle compensation value of blade 3;

the given value of the pitch angle of each blade, namely the given value of the variable pitch instruction, is equal to the original variable pitch instruction pitch output by the variable pitch controller_originalSuperimposing the respective extra pitch angle compensation values, i.e.:

pitch_demand1＝pitch_original+Δpitchangle1

pitch_demand2＝pitch_original+Δpitchangle2

pitch_demand3＝pitch_original+Δpitchangle3

in the formula, pitch_demand1Setting a pitch instruction given value for the blade 1_demand2For setting the pitch command values of the blades 2, pitch_demand3Setting a given value for a variable pitch instruction of the blade 3;

and the variable pitch controller obtains a final variable pitch instruction according to the variable pitch instruction set value of each blade, and sends the final variable pitch instruction to the variable pitch actuator for execution.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. in the normal power generation working interval of the wind generating set, the invention can only act when three conditions simultaneously meet the requirements, reduces the fatigue damage to the variable-pitch bearing caused by frequent variable pitch while reducing the deformation of the blades, and ensures the stability of the set in normal operation.

2. The invention can reduce the deformation of the blades by adopting a control mode of changing the pitch in advance when the wind generating set is in an extreme external environment, so that the set can stably run.

3. The invention has strong theoretical basis, is easy to be accepted by related technical personnel, and lays a foundation for subsequent control optimization improvement and equipment maintenance.

In conclusion, the control method and the control module for solving the clearance problem of the tower of the wind generating set provided by the invention reduce the thrust borne by the blades and the deformation of the blades in a mode of changing the pitch in advance when the blades are close to the tower, solve the clearance problem of a long-blade unit, ensure the stable operation of the unit, have practical application value and are worthy of popularization.

Drawings

FIG. 1 is a flow chart of the method of the present invention.

FIG. 2 is a control block diagram for solving a wind generating set tower clearance problem.

Fig. 3 is an architecture diagram of the module of the present invention.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto.

Example 1

As shown in fig. 1, this embodiment provides a control method for solving the clearance problem of a tower of a wind turbine generator system, the method includes monitoring a tower overturning bending moment change rate and a real-time power and a Pitch angle of a unit, and then comparing the real-time power and the Pitch angle with respective limit values to determine whether the unit is in an extreme negative shear wind condition, if the unit is not in the extreme negative shear wind condition, each blade adopts a unified Pitch control strategy, that is, an original Pitch instruction output by a Pitch controller of the unit is adopted, and once the unit is determined to be in the extreme negative shear wind condition, an independent Pitch ipc (industrial Pitch control) control strategy based on an impeller azimuth is started: increasing or decreasing the pitch angle according to different azimuth angles of the blades, reducing unbalanced stress of the blades, namely reducing a pitch angle at the azimuth angle of 0 degree, increasing forward thrust of the blades at the azimuth angle of 0 degree, increasing the pitch angle at the azimuth angle of 180 degrees, reducing the forward thrust of the blades at the azimuth angle of 180 degrees, reducing a tower overturning bending moment introduced by the unbalanced thrust, reducing a blade deformation quantity, and reducing the power fluctuation caused by the advanced pitch because the blade clearance problem only occurs when the blades are close to the tower and are near the azimuth angle of 180 degrees, so that the blades are pitched in advance before reaching the azimuth angle of 180 degrees, the blade deformation is reduced, the pitch angles of the other two blades need to be properly compensated to achieve the purpose of constant power, and finally, different extra pitch angles required by different blades are calculated to be compensated to the corresponding blades, so as to reduce the stress of a unit, namely, the blades are stressed, so that the deformation quantity and displacement of the blades are reduced, and the minimum distance from the blade tips to the surface of the tower is increased, so that the problem of tower clearance of the wind generating set is solved, and the safe and stable operation of the wind generating set is guaranteed; which comprises the following steps:

1) calculating the tower overturning bending moment change rate

Measuring the tower overturning bending moment value, and calculating the tower overturning bending moment change rate through a second-order low-pass filterThe following formula is used:

M_yf(k)＝M_y(k)*F(s)

M_yf(k-1)＝M_y(k-1)*F(s)

wherein F(s) is a second-order low-pass filter transfer function, ξ is a damping coefficient, ω is a frequency, s is a Laplace operator, k represents the current time, M is a frequency, and_y(k) is the tower overturning moment value at the current moment, M_yf(k) Is the value of the tower overturning bending moment at the current moment after being filtered, k-1 represents the previous moment, M_y(k-1) is the tower overturning moment value at the previous moment, M_yfAnd (k-1) is the value of the tower overturning bending moment after filtering at the previous moment, and T is sampling time which is generally 0.01 s.

2) Real-time power P of measuring unit_tAnd a real-time pitch angle pitch.

3) Judging whether to start independent pitch control IPC (inter-phase control) strategy

Three conditions must be met simultaneously for starting the independent pitch IPC control strategy: firstly, the change rate of the tower overturning bending moment is not less than the limit value of the change rate of the tower overturning bending moment; secondly, the real-time power is not less than the power limit value; thirdly, the real-time pitch angle is not greater than the pitch angle limit value; the method comprises the following specific steps:

wherein F is the limiting value of the change rate of the tower overturning bending moment, P_FIs a power limit value, generally 0.7 times the rated power, pitch angle_FThe pitch angle limit value is generally 4 degrees, the parameter value is only used for reference, and the actual value is set according to the running condition of the unit;

if the three conditions are met, starting an independent pitch control IPC strategy, and executing steps 4) -7); if any one of the conditions is not met, the independent pitch control IPC strategy is not started, and each blade adopts a unified pitch control strategy, namely an original pitch instruction output by a pitch controller.

4) Measuring and calculating the azimuth angle of the impeller

Measuring the azimuth angle of the blade 1, calculating the azimuth angles of the blade 2 and the blade 3 according to the fact that the three blades are uniformly distributed on an impeller plane, defining the vertical upward azimuth angle of the blade to be 0 degree, measuring through a sensor to obtain the azimuth angle of the blade 1 to be alpha, and adding the azimuth angle of the blade 2 on the basis of the azimuth angle of the blade 1The azimuth angle of the blade 3 is added on the basis of the azimuth angle of the blade 1Namely:

RotorAzimuth1＝α

in the formula, RotorAzimuth1 is the azimuth of blade 1, RotorAzimuth2 is the azimuth of blade 2, and RotorAzimuth3 is the azimuth of blade 3.

5) Calculating an additional pitch angle compensation value for each blade

When a unit is under an extreme negative shear wind condition, the stress analysis of the blades under different azimuth angles shows that the overturning bending moment load of the tower is reduced fundamentally, the deformation of the blades is reduced, and the problem of tower clearance is solved, the pitch angles can be increased or decreased according to the different azimuth angles of the blades, the stress imbalance of the blades is reduced, namely the blade changing angle is reduced at the azimuth angle of 0 degree, the forward thrust of the blades at the azimuth angle of 0 degree is increased, the blade changing angle is increased at the azimuth angle of 180 degrees, the forward thrust of the blades at the azimuth angle of 180 degrees is reduced, the overturning bending moment introduced by the unbalanced thrust is reduced, and the deformation of the blades is reduced;

because the blade clearance problem only occurs when the blades are close to the tower and are positioned near the azimuth angle of 180 degrees, the blades can be changed in advance before a certain blade reaches the azimuth angle of 180 degrees, the blade deformation is reduced, and meanwhile, in order to avoid power fluctuation caused by the advance change of the blades, the pitch angles of the other two blades can be properly compensated to achieve the aim of basically constant power;

an independent variable pitch IPC control strategy based on an impeller azimuth angle introduces a cosine function for calculating an extra pitch angle compensation value, gives an amplitude Azimuth IPCAmplite which is defined as A, and adds an angle RotorAzimuth Advance to the measured impeller azimuth angle which is defined as beta in consideration of the hysteresis of a variable pitch system of a unit, so that the effect of advance action is achieved, namely:

AzimuthIPCAmplitude＝A

RotorAzimuthAdvance＝β

Δpitchangle1＝-A*cos(α+β)

in the equation, Δ pitch 1 is the extra pitch angle compensation value of blade 1, Δ pitch 2 is the extra pitch angle compensation value of blade 2, and Δ pitch 3 is the extra pitch angle compensation value of blade 3.

6) Calculating a given value of a pitch angle of each blade, namely a given value of a pitch instruction

The given value of the variable pitch instruction is equal to the original variable pitch instruction pitch output by the variable pitch controller_originalThe extra pitch angle compensation value is superimposed, i.e.:

pitch_demand1＝pitch_original+Δpitchangle1

pitch_demand2＝pitch_original+Δpitchangle2

pitch_demand3＝pitch_original+Δpitchangle3

in the formula, pitch_demand1Setting a pitch instruction given value for the blade 1_demand2For setting the pitch command values of the blades 2, pitch_demand3Setting a given value for a variable pitch instruction of the blade 3;

and the variable pitch controller obtains a final variable pitch instruction according to the variable pitch instruction set value of each blade.

7) Performing pitch angle pitching

The variable pitch actuator of the unit adjusts the pitch angle of each blade according to a final variable pitch instruction sent by the variable pitch controller, so that the constant power can be ensured while the deformation of the blade is reduced when the blade approaches the tower, and the problem of clearance of the tower of the wind generating set is solved.

Example 2

The conventional controller of the wind generating set consists of a torque controller and a variable pitch controller: the torque controller is used for capturing wind energy maximally when the wind energy is below the rated wind speed; when the variable pitch controller is used above the rated wind speed, the rotating speed of the generator is kept near the rated rotating speed by adjusting the pitch angle, so that the output power of the generator set is guaranteed to be the rated power while the normal operation of the generator set is guaranteed. However, considering a long-blade high-tower unit, under an extreme negative shear wind condition, the problem of tower clearance is serious, analyzing the stress condition of the blades under different azimuth angles under the extreme negative shear wind condition, and establishing a new control module based on the azimuth angles, wherein the module mainly adopts an Independent Pitch Control (IPC) strategy based on the azimuth angles of the impellers to prevent the problem of tower clearance, the control strategy only acts when the unit operates under the extreme negative shear wind condition, and meanwhile, considering that if the independent Pitch control strategy is always acted in the unit operation process, the Pitch action may be frequent, so that the problem of large load of a Pitch bearing is caused, and the starting of the control strategy is limited based on the power and the Pitch angle. As shown in fig. 2, in the module, the change rate of the tower overturning bending moment and the real-time power and the pitch angle of the unit are monitored, and then are respectively compared with respective limit values, so as to judge whether the unit is in an extreme negative shear wind condition, if the unit is not in the extreme negative shear wind condition, each blade adopts a unified pitch control strategy, namely, an original pitch instruction output by a pitch controller of the unit is adopted, and once the unit is judged to be in the extreme negative shear wind condition, an independent pitch control IPC strategy based on the azimuth angle of an impeller is started: increasing or decreasing the pitch angle according to different azimuth angles of the blades, reducing unbalanced stress of the blades, namely reducing a pitch angle at the azimuth angle of 0 degree, increasing forward thrust of the blades at the azimuth angle of 0 degree, increasing the pitch angle at the azimuth angle of 180 degrees, reducing the forward thrust of the blades at the azimuth angle of 180 degrees, reducing a tower overturning bending moment introduced by the unbalanced thrust, reducing a blade deformation quantity, and reducing the power fluctuation caused by the advanced pitch because the blade clearance problem only occurs when the blades are close to the tower and are near the azimuth angle of 180 degrees, so that the blades are pitched in advance before reaching the azimuth angle of 180 degrees, the blade deformation is reduced, the pitch angles of the other two blades need to be properly compensated to achieve the purpose of constant power, and finally, different extra pitch angles required by different blades are calculated to be compensated to the corresponding blades, so as to reduce the stress of a unit, the blades are stressed, so that the deformation quantity and displacement of the blades are reduced, the minimum distance from the blade tips to the surface of the tower is increased, the problem of tower clearance of the wind generating set is solved, and the safe and stable operation of the wind generating set is guaranteed.

As shown in fig. 3, the control module for solving the problem of tower clearance of the wind generating set provided by the embodiment includes the following functional units:

the tower overturning bending moment change rate calculation unit calculates the tower overturning bending moment change rate by measuring the tower overturning bending moment value and passing through a second-order low-pass filterThe following formula is used:

M_yf(k)＝M_y(k)*F(s)

M_yf(k-1)＝M_y(k-1)*F(s)

wherein F(s) is a second-order low-pass filter transfer function, ξ is a damping coefficient, ω is a frequency, s is a Laplace operator, k represents the current time, M is a frequency, and_y(k) is the tower overturning moment value at the current moment, M_yf(k) Is the value of the tower overturning bending moment at the current moment after being filtered, k-1 represents the previous moment, M_y(k-1) is the tower overturning moment value at the previous moment, M_yfAnd (k-1) is the value of the tower overturning bending moment after filtering at the previous moment, and T is sampling time which is generally 0.01 s.

A real-time power and pitch angle measuring unit for measuring the real-time power P of the unit_tAnd a real-time pitch angle pitch.

The judging unit is used for judging whether the unit is under the extreme negative shear wind condition or not, if the unit is not under the extreme negative shear wind condition, a unified variable pitch control strategy is adopted by each blade, namely, an original variable pitch instruction output by a variable pitch controller of the unit is adopted, and once the unit is judged to be under the extreme negative shear wind condition, an independent variable pitch IPC control strategy based on an impeller azimuth angle is started; wherein, the starting of the independent pitch IPC control strategy must satisfy three conditions simultaneously: firstly, the change rate of the tower overturning bending moment is not less than the limit value of the change rate of the tower overturning bending moment; secondly, the real-time power is not less than the power limit value; thirdly, the real-time pitch angle is not greater than the pitch angle limit value; the method comprises the following specific steps:

wherein F is the limiting value of the change rate of the tower overturning bending moment, P_FIs a power limit value, generally 0.7 times the rated power, pitch angle_FThe pitch angle limit value is generally 4 degrees, the parameter value is only used for reference, and the actual value is set according to the running condition of the unit;

if the three conditions are met, starting an independent pitch control IPC strategy, and executing steps 4) -7); if any one of the conditions is not met, the independent pitch control IPC strategy is not started, and each blade adopts a unified pitch control strategy, namely an original pitch instruction output by a pitch controller.

The independent variable pitch IPC control strategy execution unit is used for calculating an impeller azimuth angle and an extra pitch angle compensation value of each blade, further calculating a given value of each blade pitch angle to obtain a final variable pitch instruction, and sending the final variable pitch instruction to a variable pitch actuator of the unit through a variable pitch controller to adjust each blade pitch angle, so that the power can be ensured to be constant while the blade deformation is reduced when the blade approaches a tower, and the problem of clearance of the tower of the wind generating set is solved; the specific operation is as follows:

measuring the azimuth angle of the blade 1, calculating the azimuth angles of the blade 2 and the blade 3 according to the fact that the three blades are uniformly distributed on an impeller plane, defining the vertical upward azimuth angle of the blade to be 0 degree, measuring through a sensor to obtain the azimuth angle of the blade 1 to be alpha, and adding the azimuth angle of the blade 2 on the basis of the azimuth angle of the blade 1The azimuth angle of the blade 3 is added on the basis of the azimuth angle of the blade 1Namely:

RotorAzimuth1＝α

wherein RotorAzimuth1 is the azimuth of blade 1, RotorAzimuth2 is the azimuth of blade 2, and RotorAzimuth3 is the azimuth of blade 3;

an independent variable pitch IPC control strategy based on an impeller azimuth angle introduces a cosine function for calculating an extra pitch angle compensation value, gives an amplitude Azimuth IPCAmplite which is defined as A, and adds an angle RotorAzimuth Advance to the measured impeller azimuth angle which is defined as beta in consideration of the hysteresis of a variable pitch system of a unit, so that the effect of advance action is achieved, namely:

AzimuthIPCAmplitude＝A

RotorAzimuthAdvance＝β

Δpitchangle1＝-A*cos(α+β)

in the formula, Δ pitch 1 is the extra pitch angle compensation value of blade 1, Δ pitch 2 is the extra pitch angle compensation value of blade 2, and Δ pitch 3 is the extra pitch angle compensation value of blade 3;

the given value of the pitch angle of each blade, namely the given value of the variable pitch instruction, is equal to the original variable pitch instruction pitch output by the variable pitch controller_originalSuperimposing the respective extra pitch angle compensation values, i.e.:

pitch_demand1＝pitch_original+Δpitchangle1

pitch_demand2＝pitch_original+Δpitchangle2

pitch_demand3＝pitch_original+Δpitchangle3

in the formula, pitch_demand1Setting a pitch instruction given value for the blade 1_demand2For setting the pitch command values of the blades 2, pitch_demand3Setting a given value for a variable pitch instruction of the blade 3;

and the variable pitch controller obtains a final variable pitch instruction according to the variable pitch instruction set value of each blade, and sends the final variable pitch instruction to the variable pitch actuator for execution.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.