阅读说明：本技术 一种风力发电机组塔架净空调控方法与模块 (Wind generating set tower clearance regulation and control method and module ) 是由 周玲 王超 任永 邹荔兵 卢军 王伟 张广兴 于 2020-12-18 设计创作，主要内容包括：本发明公开了一种风力发电机组塔架净空调控方法与模块,通过测量叶片实时方位角,判断哪个叶片处于塔架净空监测区间,测量处于塔架监测区间的那个叶片的尖端到塔架表面的最小距离,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,判断机组当前状态是否存在塔架净空安全隐患,若不存在安全隐患,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,若存在安全隐患,则启动基于单独变桨控制的塔架净空调桨控制策略,微调处于塔架净空监测区的那个叶片的桨距角,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,最终达到调控塔架净空的目的。(The invention discloses a method and a module for regulating and controlling the clearance of a tower of a wind generating set, which judge which blade is positioned in a clearance monitoring interval of the tower by measuring the real-time azimuth angle of the blade, measure the minimum distance from the tip end of the blade positioned in the monitoring interval of the tower to the surface of the tower, and the real-time power and the pitch angle of the set, and respectively compare the real-time power and the pitch angle with respective limit values to judge whether the current state of the set has the clearance potential safety hazard of the tower or not, if the potential safety hazard does not exist, each blade adopts a uniform pitch control strategy, namely, an original pitch instruction output by a pitch controller of the set is adopted, if the potential safety hazard exists, the clearance control strategy of the tower based on the independent pitch control is started, the pitch angle of the blade positioned in the clearance monitoring area of the tower is finely regulated, the stress of the set, namely the blade is, finally, the aim of regulating and controlling the tower clearance is achieved.)

1. A clearance regulation and control method for a tower of a wind generating set is characterized in that the method comprises the steps of measuring a real-time azimuth angle of a blade, judging which blade is positioned in a clearance monitoring interval of the tower, measuring the minimum distance from the tip end of the blade positioned in the monitoring interval of the tower to the surface of the tower, and the real-time power and the pitch angle of the set, comparing the real-time power and the pitch angle with respective limit values respectively, and judging whether the potential safety hazard of the clearance of the tower exists in the current state of the set, if the potential safety hazard does not exist, adopting a unified pitch control strategy for each blade, namely adopting an original pitch instruction output by a pitch controller of the set, and if the potential safety hazard exists, starting the clearance and pitch: the pitch angle of the blade in the clearance monitoring area of the tower is finely adjusted, namely, an extra pitch angle is compensated to the blade, at the moment, the given value of the variable pitch instruction of the blade is equal to the original variable pitch instruction output by the variable pitch controller, the extra pitch angle is superposed, and the original variable pitch instruction output by the variable pitch controller is adopted by the other blades, so that the unit stress is reduced, namely the blade stress is reduced, the deformation and displacement of the blade are reduced, the minimum distance from the blade tip to the surface of the tower is increased, and the aim of adjusting and controlling the clearance of the tower is finally achieved.

2. The method for regulating the clearance of the tower of the wind generating set according to claim 1, comprising the steps of:

1) 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

wherein RotorAzimuth1 is the azimuth of blade 1, RotorAzimuth2 is the azimuth of blade 2, and RotorAzimuth3 is the azimuth of blade 3; comparing azimuth angles of 3 blades, and judging which azimuth angle of the blade is in an [ A, B ] interval, wherein the [ A, B ] interval is an azimuth angle interval for starting tower clearance monitoring, namely a tower clearance monitoring interval, and when any blade azimuth angle is in the [ A, B ] interval, the blade is considered to enter the tower clearance monitoring interval;

2) measuring the minimum distance TTCA from the tip of the blade entering the clearance monitoring area of the tower to the surface of the tower and the real-time power P of the unit_tAnd a real-time pitch angle;

3) judging whether a tower clearance blade-adjusting control strategy is started or not;

the starting of the tower clearance blade-adjusting control strategy must satisfy four conditions simultaneously: firstly, the azimuth angle of the blade is not less than A and not more than B; secondly, the distance between the tip of the blade and the surface of the tower is not more than a clearance limit value of the tower; the real-time power is not less than the power limit value; fourthly, the real-time pitch angle is not greater than the pitch angle limit value; the method comprises the following specific steps:

in the formula, A isLower limit of azimuth, B upper limit of azimuth, F clearance limit of tower, P_FIs a power limit value, pitch_FIs a pitch angle limit;

if the four conditions are met, starting a tower clearance blade-adjusting control strategy, and executing the steps 4) -5); if any one of the conditions is not met, the tower clearance pitch-adjusting control strategy is not started, and each blade adopts a unified pitch-adjusting control strategy, namely an original pitch-adjusting instruction output by a pitch-adjusting controller;

4) calculating a given value of a variable pitch instruction of each blade;

when a certain blade of the blades 1, 2, 3 is within the tower clearance monitoring interval, an extra pitch angle Δ pitch is required to be added to the corresponding blade, where the extra pitch angle Δ pitch is equal to a specific pitch rate Δ pitch multiplied by a controller cycle time constant, that is:

Δpitchangle＝Δpitchrate*cycletime

at the moment, the given value of the variable pitch instruction of the blade in the clearance monitoring interval of the tower is equal to the original variable pitch instruction pitch output by the variable pitch controller_originalThe additional pitch angle delta pitch is superposed, and the given value of the variable pitch instruction of the other blades is equal to the original variable pitch instruction pitch output by the variable pitch controller_original；

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

5) 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 stable operation of the unit can be guaranteed while the deformation of the blades is reduced when the blades are close to the tower, and the problem of clearance of the tower of the wind generating set is solved.

3. The method for regulating the clearance of the tower of the wind generating set according to claim 2, wherein in the step 1), the interval [ A, B ] is defined as plus or minus 30 degrees of the vertical downward orientation of the blade.

4. According toThe method for regulating the clearance of the tower of the wind generating set as claimed in claim 2, wherein in the step 3), A is takenB takingTTCA with 1.05 times of F_min，TTCA_minMinimum tower clearance value, P, to ensure safe operation of the unit_FTaking 0.7 times of rated power, pitch_FTake 4 °.

5. The utility model provides a wind generating set pylon headroom regulation and control module, characterized in that, this module is through measuring the real-time azimuth of blade, judge which blade is in pylon headroom monitoring interval, measure the minimum distance of the tip of the blade that is in pylon monitoring interval to the surface of tower, and the real-time power and the pitch angle of unit, compare with respective limit value respectively again, judge whether the current state of unit has pylon headroom potential safety hazard, if do not have the potential safety hazard, then each blade adopts the unified control strategy of changing oar, the original instruction of changing the oar of the oar controller output that adopts the unit promptly, if there is the potential safety hazard, then start the pylon headroom of based on the individual oar control of changing oar control strategy: the pitch angle of the blade in the clearance monitoring area of the tower is finely adjusted, namely, an extra pitch angle is compensated to the blade, at the moment, the given value of the variable pitch instruction of the blade is equal to the original variable pitch instruction output by the variable pitch controller, the extra pitch angle is superposed, and the original variable pitch instruction output by the variable pitch controller is adopted by the other blades, so that the unit stress is reduced, namely the blade stress is reduced, the deformation and displacement of the blade are reduced, the minimum distance from the blade tip to the surface of the tower is increased, and the aim of adjusting and controlling the clearance of the tower is finally achieved.

6. The wind generating set tower headroom regulation module of claim 5, comprising:

the impeller azimuth angle calculation unit is used for measuring and calculating the azimuth angle of each blade so as to judge which blade is positioned in the tower clearance monitoring interval;

a clearance potential safety hazard parameter measuring unit for measuring the minimum distance TTCA from the tip of the blade entering the clearance monitoring interval of the tower to the surface of the tower and the real-time power P of the unit_tAnd a real-time pitch angle;

the judging unit is used for judging whether the current state of the unit has tower clearance potential safety hazard; if no potential safety hazard exists, adopting a unified variable pitch control strategy for each blade, namely adopting an original variable pitch instruction output by a variable pitch controller of the unit; if the potential safety hazard exists, starting a tower clearance blade-adjusting control strategy;

and the tower clearance blade-adjusting control strategy execution unit is used for calculating the given value of each blade variable-pitch instruction 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 the pitch angle of each blade, so that the stable operation of the unit can be ensured while the deformation of the blades is reduced when the blades approach the tower, and the problem of tower clearance of the wind generating set is solved.

7. The wind turbine tower clearance adjustment and control module of claim 6, wherein in the impeller azimuth calculation 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 three blades evenly distributed in an impeller plane, the vertical upward azimuth angle of the blade is defined as 0 °, 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; comparing azimuth angles of 3 blades, judging which azimuth angle of the blade is in an [ A, B ] interval, wherein the [ A, B ] interval is an azimuth angle interval for starting tower clearance monitoring, namely a tower clearance monitoring interval, and when any blade azimuth angle is in the [ A, B ] interval, considering that the blade enters the tower clearance monitoring interval.

8. The wind generating set tower clearance regulating and controlling module of claim 6, wherein in the judging unit, four conditions must be satisfied simultaneously for starting the tower clearance blade-adjusting control strategy: firstly, the azimuth angle of the blade is not less than A and not more than B; secondly, the distance between the tip of the blade and the surface of the tower is not more than a clearance limit value of the tower; the real-time power is not less than the power limit value; fourthly, the real-time pitch angle is not greater than the pitch angle limit value; the method comprises the following specific steps:

wherein A is the lower limit value of the azimuth angle, B is the upper limit value of the azimuth angle, F is the clearance limit value of the tower, P_FIs a power limit value, pitch_FIs a pitch angle limit;

if the four conditions are met, starting a tower clearance blade-adjusting control strategy; and if any one of the conditions is not met, the tower clearance blade-adjusting control strategy is not started.

9. The wind turbine generator system tower clearance regulation module of claim 6, wherein in the tower clearance blade control strategy execution unit, an extra pitch angle Δ pitchangle is added to the blade within the tower clearance monitoring interval, and the extra pitch angle Δ pitchangle is equal to a specific pitch rate Δ pitchrate multiplied by a controller cycle time constant cycletime:

Δpitchangle＝Δpitchrate*cycletime

at the moment, the given value of the variable pitch instruction of the blade in the clearance monitoring interval of the tower is equal to the original variable pitch instruction pitch output by the variable pitch controller_originalThe additional pitch angle delta pitch is superposed, and the given value of the variable pitch instruction of the other blades is equal to the original variable pitch instruction pitch output by the variable pitch controller_original。

Technical Field

The invention relates to the technical field of wind generating sets, in particular to a method and a module for regulating and controlling the clearance of a tower 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, the blades are longer and longer, and the tower is higher and higher, especially for an offshore unit, in order to capture more and better wind resources and reduce operation and maintenance costs. The wind generating set often operates in a relatively severe external environment, which causes that the load of the set is larger and larger in the operation process, the deformation of the blades is also larger, which directly causes a serious problem of tower clearance, and a great challenge is formed on the design and operation of the 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 blades are important equipment for converting wind energy into electric energy, the tower is a main bearing mechanism of the unit, and the tower clearance monitoring and the problem of tower clearance are particularly important for effectively ensuring the stable operation of the unit.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a method for regulating and controlling the clearance of a tower of a wind generating set, which can effectively reduce the deformation of blades when the blades are close to the tower and ensure that the set can stably run.

The invention also provides a wind generating set tower clearance regulation and control module.

The first purpose of the invention is realized by the following technical scheme: a clearance regulation and control method for a tower of a wind generating set comprises the steps of measuring a real-time azimuth angle of a blade, judging which blade is in a clearance monitoring interval of the tower, measuring the minimum distance from the tip end of the blade in the monitoring interval of the tower to the surface of the tower, and the real-time power and the pitch angle of the set, comparing the real-time power and the pitch angle with respective limit values, judging whether a potential safety hazard of the clearance of the tower exists in the current state of the set, if the potential safety hazard does not exist, adopting a unified pitch control strategy for each blade, namely adopting an original pitch instruction output by a pitch controller of the set, and if the potential safety hazard exists, starting a clearance control strategy for the tower based on independent: the pitch angle of the blade in the clearance monitoring area of the tower is finely adjusted, namely, an extra pitch angle is compensated to the blade, at the moment, the given value of the variable pitch instruction of the blade is equal to the original variable pitch instruction output by the variable pitch controller, the extra pitch angle is superposed, and the original variable pitch instruction output by the variable pitch controller is adopted by the other blades, so that the unit stress is reduced, namely the blade stress is reduced, the deformation and displacement of the blade are reduced, the minimum distance from the blade tip to the surface of the tower is increased, and the aim of adjusting and controlling the clearance of the tower is finally achieved.

The wind generating set tower clearance regulation and control method comprises the following steps:

1) 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

wherein RotorAzimuth1 is the azimuth of blade 1, RotorAzimuth2 is the azimuth of blade 2, and RotorAzimuth3 is the azimuth of blade 3; comparing azimuth angles of 3 blades, and judging which azimuth angle of the blade is in an [ A, B ] interval, wherein the [ A, B ] interval is an azimuth angle interval for starting tower clearance monitoring, namely a tower clearance monitoring interval, and when any blade azimuth angle is in the [ A, B ] interval, the blade is considered to enter the tower clearance monitoring interval;

2) measuring the minimum distance TTCA from the tip of the blade entering the clearance monitoring area of the tower to the surface of the tower and the real-time power P of the unit_tAnd a real-time pitch angle;

3) judging whether a tower clearance blade-adjusting control strategy is started or not;

the starting of the tower clearance blade-adjusting control strategy must satisfy four conditions simultaneously: firstly, the azimuth angle of the blade is not less than A and not more than B; secondly, the distance between the tip of the blade and the surface of the tower is not more than a clearance limit value of the tower; the real-time power is not less than the power limit value; fourthly, the real-time pitch angle is not greater than the pitch angle limit value; the method comprises the following specific steps:

wherein A is the lower limit value of the azimuth angle, B is the upper limit value of the azimuth angle, F is the clearance limit value of the tower, P_FIs a power limit value, pitch_FIs a pitch angle limit;

if the four conditions are met, starting a tower clearance blade-adjusting control strategy, and executing the steps 4) -5); if any one of the conditions is not met, the tower clearance pitch-adjusting control strategy is not started, and each blade adopts a unified pitch-adjusting control strategy, namely an original pitch-adjusting instruction output by a pitch-adjusting controller;

4) calculating a given value of a variable pitch instruction of each blade;

when a certain blade of the blades 1, 2, 3 is within the tower clearance monitoring interval, an extra pitch angle Δ pitch is required to be added to the corresponding blade, where the extra pitch angle Δ pitch is equal to a specific pitch rate Δ pitch multiplied by a controller cycle time constant, that is:

Δpitchangle＝Δpitchrate*cycletime

at the moment, the given value of the variable pitch instruction of the blade in the clearance monitoring interval of the tower is equal to the original variable pitch instruction pitch output by the variable pitch controller_originalThe additional pitch angle delta pitch is superposed, and the given value of the variable pitch instruction of the other blades is equal to the original variable pitch instruction pitch output by the variable pitch controller_original；

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

5) 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 stable operation of the unit can be guaranteed while the deformation of the blades is reduced when the blades are close to the tower, and the problem of clearance of the tower of the wind generating set is solved.

In step 1), the [ A, B ] interval is defined as plus or minus 30 ° of the vertical downward orientation of the blade.

In step 3), A is takenB takingTTCA with 1.05 times of F_min，TTCA_minMinimum tower clearance value, P, to ensure safe operation of the unit_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 wind generating set pylon headroom regulation and control module, this module is through measuring the real-time azimuth of blade, judge which blade is in pylon headroom monitoring interval, measure the minimum distance that the most advanced of the blade that is in pylon monitoring interval reaches the pylon surface, and the real-time power and the pitch angle of unit, the difference is compared with respective limiting value again respectively, judge whether the current state of unit has pylon headroom potential safety hazard, if do not have the potential safety hazard, then each blade adopts the unified oar control strategy that becomes, the original oar instruction that becomes of the oar controller output that adopts the unit promptly, if there is the potential safety hazard, then start the clearance pylon of changing oar based on the individual oar control and adjust the oar control strategy: the pitch angle of the blade in the clearance monitoring area of the tower is finely adjusted, namely, an extra pitch angle is compensated to the blade, at the moment, the given value of the variable pitch instruction of the blade is equal to the original variable pitch instruction output by the variable pitch controller, the extra pitch angle is superposed, and the original variable pitch instruction output by the variable pitch controller is adopted by the other blades, so that the unit stress is reduced, namely the blade stress is reduced, the deformation and displacement of the blade are reduced, the minimum distance from the blade tip to the surface of the tower is increased, and the aim of adjusting and controlling the clearance of the tower is finally achieved.

Wind generating set tower headroom regulation and control module include:

the impeller azimuth angle calculation unit is used for measuring and calculating the azimuth angle of each blade so as to judge which blade is positioned in the tower clearance monitoring interval;

a clearance potential safety hazard parameter measuring unit for measuring the minimum distance TTCA from the tip of the blade entering the clearance monitoring interval of the tower to the surface of the tower and the real-time power P of the unit_tAnd a real-time pitch angle;

the judging unit is used for judging whether the current state of the unit has tower clearance potential safety hazard; if no potential safety hazard exists, adopting a unified variable pitch control strategy for each blade, namely adopting an original variable pitch instruction output by a variable pitch controller of the unit; if the potential safety hazard exists, starting a tower clearance blade-adjusting control strategy;

and the tower clearance blade-adjusting control strategy execution unit is used for calculating the given value of each blade variable-pitch instruction 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 the pitch angle of each blade, so that the stable operation of the unit can be ensured while the deformation of the blades is reduced when the blades approach the tower, and the problem of tower clearance of the wind generating set is solved.

Further, in the impeller azimuth angle calculation unit, an azimuth angle of the blade 1 is measured, 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 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 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; comparing azimuth angles of 3 blades, judging which azimuth angle of the blade is in an [ A, B ] interval, wherein the [ A, B ] interval is an azimuth angle interval for starting tower clearance monitoring, namely a tower clearance monitoring interval, and when any blade azimuth angle is in the [ A, B ] interval, considering that the blade enters the tower clearance monitoring interval.

Further, in the determining unit, four conditions must be simultaneously satisfied when the tower clearance blade-adjusting control strategy is started: firstly, the azimuth angle of the blade is not less than A and not more than B; secondly, the distance between the tip of the blade and the surface of the tower is not more than a clearance limit value of the tower; the real-time power is not less than the power limit value; fourthly, the real-time pitch angle is not greater than the pitch angle limit value; the method comprises the following specific steps:

wherein A is the lower limit value of the azimuth angle, B is the upper limit value of the azimuth angle, F is the clearance limit value of the tower, P_FIs a power limit value, pitch_FIs a pitch angle limit;

if the four conditions are met, starting a tower clearance blade-adjusting control strategy; and if any one of the conditions is not met, the tower clearance blade-adjusting control strategy is not started.

Further, in the tower clearance blade-adjusting control strategy executing unit, an extra pitch angle Δ pitch is added to the blade within the tower clearance monitoring interval, where the extra pitch angle Δ pitch is equal to a specific pitch rate Δ pitch multiplied by a controller cycle time constant, namely:

Δpitchangle＝Δpitchrate*cycletime

at the moment, the given value of the variable pitch instruction of the blade in the clearance monitoring interval of the tower is equal to the original variable pitch instruction pitch output by the variable pitch controller_originalThe additional pitch angle delta pitch is superposed, and the given value of the variable pitch instruction of the other blades is equal to the original variable pitch instruction pitch output by the variable pitch controller_original。

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 four conditions simultaneously meet the requirements, so that the fatigue damage to a variable-pitch bearing caused by frequent variable pitch is reduced while the deformation of the blades is reduced, and the stability of the set in normal operation is ensured.

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 clearance regulation and control method and the module for the tower of the wind generating set provided by the invention have the advantages that the thrust borne by the blades and the deformation of the blades are reduced in a mode of changing the pitch in advance when the blades are close to the tower and the potential clearance hazard is monitored, the clearance problem of a long-blade unit is solved, the stable operation of the unit is ensured, the practical application value is realized, and the popularization is worth.

Drawings

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

FIG. 2 is a control block diagram of tower clearance regulation of a wind generating set.

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

Detailed Description

The present invention will be further described with reference to the following specific examples.

Example 1

As shown in fig. 1, this embodiment provides a method for regulating and controlling a clearance of a tower of a wind turbine generator system, where the method includes determining, by measuring a real-time azimuth angle of a blade, which blade is located in a clearance monitoring interval of the tower, measuring a minimum distance from a tip of the blade located in the monitoring interval of the tower to a surface of the tower, and a real-time power and a pitch angle of the unit, and comparing the measured values with respective limit values, determining whether a potential safety hazard of the clearance of the tower exists in a current state of the unit, if the potential safety hazard does not exist, 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 if the potential safety hazard exists, starting a clearance and pitch: finely adjusting the pitch angle of the blade in the clearance monitoring area of the tower, namely compensating an extra pitch angle to the blade, wherein the given value of a variable pitch instruction of the blade is equal to the original variable pitch instruction output by a variable pitch controller and the extra pitch angle is superposed, and the original variable pitch instruction output by the variable pitch controller is adopted by the other blades, so that the stress of a unit, namely the stress of the blade is reduced, the deformation and displacement of the blade are reduced, the minimum distance from the blade tip to the surface of the tower is increased, and the aim of adjusting and controlling the clearance of the tower is finally achieved; which comprises the following steps:

1) 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

wherein RotorAzimuth1 is the azimuth of blade 1, RotorAzimuth2 is the azimuth of blade 2, and RotorAzimuth3 is the azimuth of blade 3; comparing the azimuth angles of 3 blades, judging which blade azimuth angle is in an [ A, B ] interval, wherein the [ A, B ] interval is an azimuth angle interval for starting tower clearance monitoring, namely a tower clearance monitoring interval, generally defined as positive and negative 30 degrees of a vertical downward azimuth of the blade, and when any blade azimuth angle is in the [ A, B ] interval, the blade is considered to enter the tower clearance monitoring interval.

2) Measuring the minimum distance TTCA from the tip of the blade entering the clearance monitoring area of the tower to the surface of the tower and the real-time power P of the unit_tAnd a real-time pitch angle pitch.

3) Control strategy for judging whether to start tower clearance blade adjustment

The starting of the tower clearance blade-adjusting control strategy must satisfy four conditions simultaneously: firstly, the azimuth angle of the blade is not less than A and not more than B; secondly, the distance between the tip of the blade and the surface of the tower is not more than a clearance limit value of the tower; the real-time power is not less than the power limit value; fourthly, the real-time pitch angle is not greater than the pitch angle limit value; the method comprises the following specific steps:

wherein A is the lower limit of azimuth angle, and is generally takenB is an upper limit value of azimuth, and is generally takenF is a tower clearance limiting value, and aiming at different types of machines, a minimum tower clearance value TTCA (time to failure) for ensuring the safe operation of a unit can be calculated_minIn order to ensure safety, F is 1.05 times of TTCA_min；P_FThe power limit value is generally 0.7 times of rated power; batch 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 four conditions are met, starting a tower clearance blade-adjusting control strategy, and executing the steps 4) -5); if any one of the conditions is not met, the tower clearance pitch control strategy is not started, and each blade adopts a unified pitch control strategy, namely an original pitch instruction output by a pitch controller.

4) Calculating the given value of the variable pitch instruction of each blade

When a certain blade of the blades 1, 2, 3 is within the tower clearance monitoring interval, an extra pitch angle Δ pitch is required to be added to the corresponding blade, where the extra pitch angle Δ pitch is equal to a specific pitch rate Δ pitch multiplied by a controller cycle time constant, that is:

Δpitchangle＝Δpitchrate*cycletime

at the moment, the given value of the variable pitch instruction of the blade in the clearance monitoring interval of the tower is equal to the original variable pitch instruction pitch output by the variable pitch controller_originalThe additional pitch angle delta pitch is superposed, and the given value of the variable pitch instruction of the other blades is equal to the original variable pitch instruction pitch output by the variable pitch controller_original；

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

5) 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 stable operation of the unit can be guaranteed while the deformation of the blades is reduced when the blades are close to 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 that a long-blade high tower unit has serious tower clearance problem, measuring an azimuth angle, judging whether a blade enters a tower clearance monitoring interval or not, establishing a new module on the basis of a conventional variable pitch controller, wherein the module mainly adopts a tower clearance and pitch adjustment control strategy based on independent variable pitch control to prevent the tower clearance problem from occurring, the control strategy only plays a role when the tower clearance safety hidden danger of the unit is monitored, and meanwhile, considering that if the control strategy plays a role all the time in the unit operation process, the control strategy can cause the loss of generated energy to reduce economic benefit and the variable pitch bearing load is large due to frequent variable pitch action, the starting interval of the control strategy is also limited based on the blade azimuth angle, the unit real-time power and the pitch angle. As shown in fig. 2, the module determines which blade is in the tower clearance monitoring interval by measuring the real-time azimuth angle of the blade, measures the minimum distance from the tip of the blade in the tower monitoring interval to the tower surface, and the real-time power and the pitch angle of the unit, and compares the measured values with respective limit values to determine whether the current state of the unit has a tower clearance potential safety hazard, if no potential safety hazard exists, each blade adopts a unified pitch control strategy, namely, an original pitch instruction output by a pitch controller of the unit is adopted, and if a potential safety hazard exists, a tower clearance pitch control strategy based on individual pitch control is started: the pitch angle of the blade in the clearance monitoring area of the tower is finely adjusted, namely, an extra pitch angle is compensated to the blade, at the moment, the given value of the variable pitch instruction of the blade is equal to the original variable pitch instruction output by the variable pitch controller, the extra pitch angle is superposed, and the original variable pitch instruction output by the variable pitch controller is adopted by the other blades, so that the unit stress is reduced, namely the blade stress is reduced, the deformation and displacement of the blade are reduced, the minimum distance from the blade tip to the surface of the tower is increased, and the aim of adjusting and controlling the clearance of the tower is finally achieved.

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

the impeller azimuth angle calculating unit is used for measuring and calculating the azimuth angle of each blade so as to judge which blade is in a tower clearance monitoring interval, and the specific conditions are 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; comparing the azimuth angles of 3 blades, judging which blade azimuth angle is in an [ A, B ] interval, wherein the [ A, B ] interval is an azimuth angle interval for starting tower clearance monitoring, namely a tower clearance monitoring interval, generally defined as positive and negative 30 degrees of a vertical downward azimuth of the blade, and when any blade azimuth angle is in the [ A, B ] interval, the blade is considered to enter the tower clearance monitoring interval.

A clearance potential safety hazard parameter measuring unit for measuring the minimum distance TTCA from the tip of the blade entering the clearance monitoring interval of the tower to the surface of the tower and the real-time power P of the unit_tAnd a real-time pitch angle pitch.

The judging unit is used for judging whether the current state of the unit has tower clearance potential safety hazard; if no potential safety hazard exists, adopting a unified variable pitch control strategy for each blade, namely adopting an original variable pitch instruction output by a variable pitch controller of the unit; if the potential safety hazard exists, starting a tower clearance blade-adjusting control strategy; wherein, the starting of the tower clearance blade-adjusting control strategy must simultaneously satisfy four conditions: firstly, the azimuth angle of the blade is not less than A and not more than B; secondly, the distance between the tip of the blade and the surface of the tower is not more than a clearance limit value of the tower; the real-time power is not less than the power limit value; fourthly, the real-time pitch angle is not greater than the pitch angle limit value; the method comprises the following specific steps:

wherein A is the lower limit of azimuth angle, and is generally takenB is an upper limit value of azimuth, and is generally takenF is a tower clearance limiting value, and aiming at different types of machines, a minimum tower clearance value TTCA (time to failure) for ensuring the safe operation of a unit can be calculated_minIn order to ensure safety, F is 1.05 times of TTCA_min；P_FThe power limit value is generally 0.7 times of rated power; batch 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 four conditions are met, starting a tower clearance blade-adjusting control strategy; if any one of the conditions is not met, the tower clearance pitch control strategy is not started, and each blade adopts a unified pitch control strategy, namely an original pitch instruction output by a pitch controller.

The tower clearance blade-adjusting control strategy executing unit is used for calculating a given value of each blade variable-pitch instruction 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 the pitch angle of each blade, so that the stable operation of the unit can be guaranteed while the deformation of the blades is reduced when the blades approach the tower, and the problem of tower clearance of the wind generating set is solved; wherein, an extra pitch angle Δ pitch needs to be added to the blade within the tower clearance monitoring interval, and the extra pitch angle Δ pitch is equal to the specific pitch rate Δ pitch multiplied by the controller cycle time constant, namely:

Δpitchangle＝Δpitchrate*cycletime

at the moment, the given value of the variable pitch instruction of the blade in the clearance monitoring interval of the tower is equal to the original variable pitch instruction pitch output by the variable pitch controller_originalThe additional pitch angle delta pitch is superposed, and the given value of the variable pitch instruction of the other blades is equal to the original variable pitch instruction pitch output by the variable pitch controller_original。

The above-mentioned embodiments are merely preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, so that the changes in the shape and principle of the present invention should be covered within the protection scope of the present invention.