阅读说明：本技术 塔架刚度控制方法、装置及风力发电机组可变刚度塔架 (Tower stiffness control method and device and variable stiffness tower of wind generating set ) 是由 袁凌 郑梁 李英昌 员一泽 朱孝晗 于国亮 于 2021-01-13 设计创作，主要内容包括：本发明提供一种塔架刚度控制方法、装置及风力发电机组可变刚度塔架,该方法包括：获取风轮一倍频频率、塔架振动频率及塔架一阶固有频率；当风轮一倍频率落入塔架一阶固有频率的第一临近区间内,控制塔架变刚度执行机构按照第一频率差与风轮一倍频率的比值改变塔架刚度；当风轮一倍频率未落入第一临近区间内,且风轮一倍频率落入塔架振动频率的第二临近区间内,控制塔架变刚度执行机构按照第二频率差与风轮一倍频率的比值改变塔架刚度。本发明可以根据风轮转速和塔架瞬时固有频率,实时动态调整塔架刚度,从而避免塔架与风轮共振和减轻塔架非固有频率的瞬态共振振幅。(The invention provides a method and a device for controlling the rigidity of a tower and a variable-rigidity tower of a wind generating set, wherein the method comprises the following steps: acquiring a first-order frequency multiplication frequency of a wind wheel, a tower vibration frequency and a first-order natural frequency of a tower; when the one-time frequency of the wind wheel falls into a first adjacent interval of the first-order natural frequency of the tower, controlling a tower stiffness changing actuating mechanism to change the tower stiffness according to the ratio of the first frequency difference to the one-time frequency of the wind wheel; when the first frequency of the wind wheel does not fall into the first adjacent interval and the first frequency of the wind wheel falls into the second adjacent interval of the tower vibration frequency, the tower rigidity changing actuating mechanism is controlled to change the tower rigidity according to the ratio of the second frequency difference to the first frequency of the wind wheel. The invention can dynamically adjust the rigidity of the tower in real time according to the rotating speed of the wind wheel and the instantaneous natural frequency of the tower, thereby avoiding the resonance of the tower and the wind wheel and reducing the transient resonance amplitude of the non-natural frequency of the tower.)

1. A tower rigidity control method is applied to a variable rigidity tower of a wind generating set, wherein the variable rigidity tower of the wind generating set comprises a tower rigidity variable actuating mechanism, and the method comprises the following steps:

acquiring a first-order frequency multiplication frequency of a wind wheel, a tower vibration frequency and a first-order natural frequency of a tower;

when the one-time frequency of the wind wheel falls into a first adjacent interval of the first-order natural frequency of the tower, controlling the tower stiffness changing actuating mechanism to change the tower stiffness according to the ratio of the first frequency difference to the one-time frequency of the wind wheel; the first frequency difference is the difference between a first-order frequency multiplication frequency of the wind wheel and a first-order natural frequency of the tower;

when the one-time frequency of the wind wheel does not fall into the first adjacent interval and the one-time frequency of the wind wheel falls into the second adjacent interval of the tower vibration frequency, controlling the tower stiffness changing actuating mechanism to change the tower stiffness according to the ratio of the second frequency difference to the one-time frequency of the wind wheel; the second frequency difference is a difference between a first frequency multiplication frequency of the wind wheel and a vibration frequency of the tower.

2. The method of claim 1, wherein the tower variable stiffness actuator comprises a servo motor and a moving member, the moving member being mounted laterally inside the tower;

the control of the tower stiffness varying executing mechanism changes the tower stiffness according to the ratio of the first frequency difference to the frequency which is one time higher than the wind wheel frequency, and comprises the following steps:

determining the rotation angle of the servo motor according to the ratio of the first frequency difference to the one-time frequency of the wind wheel;

and controlling the servo motor to rotate according to the rotation angle so as to drive the moving part to move transversely and change the rigidity of the tower.

3. The method of claim 2, wherein the wind turbine primary octave frequency is f'_r1And said tower has a first order natural frequency of f_t1Determining a rotation angle of the servo motor according to a ratio of the first frequency difference to one frequency multiple of the wind wheel, comprising:

when f'_r1＜0.85f_t1Or f'_r1＞1.15f_t1When the servo motor is not output, the control signal is not output; alternatively, the first and second electrodes may be,

when 0.85f_t1≤f′_r1≤1.15f_t1Then, according to | f'_r1-f_t1|/f′_r1Outputting a control signal; alternatively, the first and second electrodes may be,

when the rotating speed of the wind wheel is reduced to f'_r1＜0.85f_t1In time, in a first preset time period, | f'_r1-f_t1|/f′_r1The control signal linearly decreases to 0; alternatively, the first and second electrodes may be,

when the rotating speed of the wind wheel rises to f'_r1＞1.15f_t1Then | f 'is set within a second preset time length'_r1-f_t1|/f′_r1The control signal linearly decreases to 0;

determining a rotation angle omega of the servo motor according to the control signal, wherein a control function of the rotation angle omega is omega-A-f'_r1-f_t1|/f′_r1Wherein A is a gain factor.

4. The method of claim 1, wherein the tower variable stiffness actuator comprises a servo motor and a moving member, the moving member being mounted laterally inside the tower;

the control of the tower stiffness varying executing mechanism changes the tower stiffness according to the ratio of the second frequency difference to the frequency which is one time higher than the wind wheel frequency, and comprises the following steps:

determining the rotation angle of the servo motor according to the ratio of the second frequency difference to the frequency of the wind wheel;

and controlling the servo motor to rotate according to the rotation angle so as to drive the moving part to move transversely and change the rigidity of the tower.

5. A method according to claim 4, wherein the wind wheel first octave frequency is f'_r1Wherein the tower vibration frequency is f'_tAnd said tower has a first order natural frequency of f_t1Determining a rotation angle of the servo motor according to a ratio of the second frequency difference to one frequency multiple of the wind wheel, comprising:

when f'_r1＜0.85f_t1Or f'_r1＞1.15f_t1And 0.95 f'_t≤f′_r1≤1.05f′_tThen, according to | f'_r1-f′_t|/f′_r1Outputting a control signal; alternatively, the first and second electrodes may be,

when the rotating speed of the wind wheel is reduced to f'_r1＜0.95f′_tThen | f 'is set within a third preset time length'_r1-f′_t|/f′_r1The control signal is linearly shifted to 0; alternatively, the first and second electrodes may be,

when the rotating speed of the wind wheel rises to f'_r1＞1.15f′_tThen | f 'is set within a fourth preset time length'_r1-f′_t|/f′_r1The control signal is linearly shifted to 0;

determining a rotation angle omega of the servo motor according to the control signal, wherein a control function of the rotation angle omega is omega-A-f'_r1-f_t1|/f′_r1Wherein A is a gain factor.

6. The method of claim 2 or 4, further comprising:

acquiring the maximum length of the transverse movement of the moving part, and determining the maximum rotation angle of the servo motor corresponding to the maximum length;

the control servo motor rotates according to turned angle includes:

and if the rotation angle is larger than the maximum rotation angle, controlling the servo motor to rotate according to the maximum rotation angle.

7. The method of claim 1, wherein obtaining a first octave frequency of the rotor, a tower vibration frequency, and a first order natural tower frequency comprises:

acquiring continuous transient rotating speed of a wind wheel through a wind wheel rotating speed sensor, and performing digital filtering, steady-state processing and band-pass filtering on the continuous transient rotating speed of the wind wheel to obtain first frequency multiplication frequency of the wind wheel;

the method comprises the steps of obtaining the vibration acceleration of the tower through a tower vibration acceleration sensor, and carrying out digital filtering, time domain-frequency domain conversion and band-pass filtering according to the vibration acceleration of the tower to obtain the vibration frequency of the tower.

8. A tower rigidity control device is applied to a wind generating set variable rigidity tower, the wind generating set variable rigidity tower comprises a tower rigidity variable actuating mechanism, and the device comprises:

the acquisition module is used for acquiring a first-order frequency multiplication frequency of the wind wheel, a tower vibration frequency and a first-order natural frequency of the tower;

the first control module is used for controlling the tower stiffness changing actuating mechanism to change the tower stiffness according to the ratio of a first frequency difference to the wind wheel frequency multiplication when the wind wheel frequency multiplication falls into a first adjacent interval of the tower first-order natural frequency multiplication; the first frequency difference is the difference between a first-order frequency multiplication frequency of the wind wheel and a first-order natural frequency of the tower;

the second control module is used for controlling the tower stiffness varying executing mechanism to vary the tower stiffness according to the ratio of a second frequency difference to the wind wheel frequency one when the wind wheel frequency one does not fall into the first adjacent interval and the wind wheel frequency one falls into a second adjacent interval of the tower vibration frequency; the second frequency difference is a difference between a first frequency multiplication frequency of the wind wheel and a vibration frequency of the tower.

9. A variable stiffness tower for a wind generating set, comprising: the wind wheel rotating speed sensor, the tower vibration acceleration sensor, the tower variable-rigidity executing mechanism and the driving controller are arranged on the wind wheel rotating speed sensor;

the wind wheel rotating speed sensor is used for acquiring the rotating speed of the wind wheel;

the tower vibration acceleration sensor is used for acquiring the tower vibration acceleration;

the driving controller is used for executing the tower rigidity control method of any one of claims 1 to 7 to control the tower rigidity changing actuator to change the tower rigidity.

10. The wind generating set variable stiffness tower of claim 9, wherein the tower variable stiffness actuator includes servo electric cylinders and at least one connecting rod;

one end of the connecting rod is connected with the inner wall of the tower through a mounting seat, and the other end of the connecting rod is connected with the top end of a lead screw of the servo electric cylinder;

the servo electric cylinder is used for changing the extending length of the lead screw so as to drive the connecting rod to move transversely and change the acting force applied to the inner wall of the tower by the connecting rod.

11. The variable stiffness tower of claim 10, comprising a first connecting rod and a second connecting rod;

the first connecting rod, the servo motor and the second connecting rod are sequentially connected, and the first connecting rod and the second connecting rod are connected with the inner wall of the tower frame through mounting seats.

12. The variable stiffness tower of claim 11, wherein the first and second connecting rods are each connected to the mounting base by a connecting pin.

Technical Field

The invention relates to the technical field of tower resonance prevention, in particular to a tower rigidity control method and device and a variable rigidity tower of a wind generating set.

Background

The tower is a main supporting component of the wind generating set, and supports the engine room and the wind wheel at a certain height, so that the wind generating set can obtain wind power resources meeting requirements. The tower of the large-scale wind generating set is generally formed into a cylindrical structure of a cylinder or a cone by adopting the modes of rolling, welding and the like of a steel plate, the first-order natural frequency is higher than the first-order frequency (1P) frequency of a wind wheel, and the resonance of the tower can not be caused when the wind generating set works.

With the continuous development of wind power technology, larger wind wheel diameter and higher tower frame become the main trend of wind power development, the height of the tower frame of a large megawatt wind generating set is generally more than tens of meters, even more than one hundred meters, and the manufacturing cost of the tower frame is greatly increased along with the rising of the height. When the height of the tower exceeds one hundred meters, the weight is exponentially increased, the cost is increased, and the economy is low. Therefore, the high tower is often designed to reduce weight, the first-order natural frequency of the high tower is lower than the first-order frequency multiplication frequency of the wind wheel, and the high tower and the wind wheel can resonate in a working interval.

In order to avoid the problems, the existing scheme is to control the running rotating speed of a wind wheel to quickly jump over a resonance area by controlling a pitch-controlled yaw brake and adjusting the electromagnetic torque of a generator, so that the reliability is not high, and the tower collapse accident caused by the failure of a control system occurs. In addition, no control measures are taken for transient resonance of the tower non-natural frequency, which can cause the tower to vibrate greatly and is very unfavorable for the structure.

Disclosure of Invention

The invention solves the problem that the existing method can not effectively avoid the problem that the tower and the wind wheel share and reduce the transient resonance amplitude of the non-inherent frequency of the tower.

In order to solve the above problems, the present invention provides a tower stiffness control method, which is applied to a variable stiffness tower of a wind generating set, where the variable stiffness tower of the wind generating set includes a tower stiffness variation actuator, and the method includes: acquiring a first-order frequency multiplication frequency of a wind wheel, a tower vibration frequency and a first-order natural frequency of a tower; when the one-time frequency of the wind wheel falls into a first adjacent interval of the first-order natural frequency of the tower, controlling the tower stiffness changing actuating mechanism to change the tower stiffness according to the ratio of the first frequency difference to the one-time frequency of the wind wheel; the first frequency difference is the difference between a first-order frequency multiplication frequency of the wind wheel and a first-order natural frequency of the tower; when the one-time frequency of the wind wheel does not fall into the first adjacent interval and the one-time frequency of the wind wheel falls into the second adjacent interval of the tower vibration frequency, controlling the tower stiffness changing actuating mechanism to change the tower stiffness according to the ratio of the second frequency difference to the one-time frequency of the wind wheel; the second frequency difference is a difference between a first frequency multiplication frequency of the wind wheel and a vibration frequency of the tower.

Optionally, the tower stiffness varying actuating mechanism includes a servo motor and a moving member, and the moving member is transversely installed inside the tower; the control of the tower stiffness varying executing mechanism changes the tower stiffness according to the ratio of the first frequency difference to the frequency which is one time higher than the wind wheel frequency, and comprises the following steps: determining the rotation angle of the servo motor according to the ratio of the first frequency difference to the one-time frequency of the wind wheel; and controlling the servo motor to rotate according to the rotation angle so as to drive the moving part to move transversely and change the rigidity of the tower.

Optionally, the primary doubling frequency of the wind wheel is f'_r1And said tower has a first order natural frequency of f_t1Determining a rotation angle of the servo motor according to a ratio of the first frequency difference to one frequency multiple of the wind wheel, comprising: when f'_r1＜0.85f_t1Or f'_r1＞1.15f_t1When the servo motor is not output, the control signal is not output; or, when 0.85f_t1≤f′_r1≤1.15f_t1Then, according to | f'_r1-f_t1|/f′_r1Outputting a control signal; or when the rotating speed of the wind wheel is reduced to f'_r1＜0.85f_t1In time, in a first preset time period, | f'_r1-f_t1|/f′_r1The control signal linearly decreases to 0; or when the rotation speed of the wind wheel rises to f'_r1＞1.15f_t1Then | f 'is set within a second preset time length'_r1-f_t1|/f′_r1The control signal linearly decreases to 0; determining a rotation angle omega of the servo motor according to the control signal, wherein a control function of the rotation angle omega is omega-A-f'_r1-f_t1|/f′_r1Wherein A is a gain factor.

Optionally, the tower stiffness varying actuating mechanism includes a servo motor and a moving member, and the moving member is transversely installed inside the tower; the control of the tower stiffness varying executing mechanism changes the tower stiffness according to the ratio of the second frequency difference to the frequency which is one time higher than the wind wheel frequency, and comprises the following steps: determining the rotation angle of the servo motor according to the ratio of the second frequency difference to the frequency of the wind wheel; and controlling the servo motor to rotate according to the rotation angle so as to drive the moving part to move transversely and change the rigidity of the tower.

Optionally, the primary doubling frequency of the wind wheel is f'_r1Wherein the tower vibration frequency is f'_tAnd said tower has a first order natural frequency of f_t1Determining a rotation angle of the servo motor according to a ratio of the second frequency difference to one frequency multiple of the wind wheel, comprising: when f'_r1＜0.85f_t1Or f'_r1＞1.15f_t1And 0.95 f'_t≤f′_r1≤1.05f′_tThen, according to | f'_r1-f′_t|/f′_r1Outputting a control signal; or when the rotating speed of the wind wheel is reduced to f'_r1＜0.95f′_tThen | f 'is set within a third preset time length'_r1-f′_t|/f′_r1The control signal is linearly shifted to 0; or when the rotation speed of the wind wheel rises to f'_r1＞1.15f′_tThen | f 'is set within a fourth preset time length'_r1-f′_t|/f′_r1The control signal is linearly shifted to 0; determining servo based on the control signalA rotation angle ω of the motor, wherein a control function of the rotation angle ω is ω ═ a | f'_r1-f_t1|/f′_r1Wherein A is a gain factor.

Optionally, the method further comprises: acquiring the maximum length of the transverse movement of the moving part, and determining the maximum rotation angle of the servo motor corresponding to the maximum length; the control servo motor rotates according to turned angle includes: and if the rotation angle is larger than the maximum rotation angle, controlling the servo motor to rotate according to the maximum rotation angle.

Optionally, the obtaining a first-order double frequency of the wind turbine, a tower vibration frequency, and a first-order natural frequency of the tower includes: acquiring continuous transient rotating speed of a wind wheel through a wind wheel rotating speed sensor, and performing digital filtering, steady-state processing and band-pass filtering on the continuous transient rotating speed of the wind wheel to obtain first frequency multiplication frequency of the wind wheel; the method comprises the steps of obtaining the vibration acceleration of the tower through a tower vibration acceleration sensor, and carrying out digital filtering, time domain-frequency domain conversion and band-pass filtering according to the vibration acceleration of the tower to obtain the vibration frequency of the tower.

The invention provides a tower rigidity control device, which is applied to a variable rigidity tower of a wind generating set, wherein the variable rigidity tower of the wind generating set comprises a tower rigidity variable actuating mechanism, and the device comprises: the acquisition module is used for acquiring a first-order frequency multiplication frequency of the wind wheel, a tower vibration frequency and a first-order natural frequency of the tower; the first control module is used for controlling the tower stiffness changing actuating mechanism to change the tower stiffness according to the ratio of a first frequency difference to the wind wheel frequency multiplication when the wind wheel frequency multiplication falls into a first adjacent interval of the tower first-order natural frequency multiplication; the first frequency difference is the difference between a first-order frequency multiplication frequency of the wind wheel and a first-order natural frequency of the tower; the second control module is used for controlling the tower stiffness varying executing mechanism to vary the tower stiffness according to the ratio of a second frequency difference to the wind wheel frequency one when the wind wheel frequency one does not fall into the first adjacent interval and the wind wheel frequency one falls into a second adjacent interval of the tower vibration frequency; the second frequency difference is a difference between a first frequency multiplication frequency of the wind wheel and a vibration frequency of the tower.

The invention provides a variable rigidity tower of a wind generating set, which comprises: the wind wheel rotating speed sensor, the tower vibration acceleration sensor, the tower variable-rigidity executing mechanism and the driving controller are arranged on the wind wheel rotating speed sensor; the wind wheel rotating speed sensor is used for acquiring the rotating speed of the wind wheel; the tower vibration acceleration sensor is used for acquiring the tower vibration acceleration; the driving controller is used for executing the tower rigidity control method so as to control the tower rigidity changing actuating mechanism to change the tower rigidity.

Optionally, the tower stiffness-variable actuator comprises a servo electric cylinder and at least one connecting rod; one end of the connecting rod is connected with the inner wall of the tower through a mounting seat, and the other end of the connecting rod is connected with the top end of a lead screw of the servo electric cylinder; the servo electric cylinder is used for changing the extending length of the lead screw so as to drive the connecting rod to move transversely and change the acting force applied to the inner wall of the tower by the connecting rod.

Optionally, a first connecting rod and a second connecting rod are included; the first connecting rod, the servo motor and the second connecting rod are sequentially connected, and the first connecting rod and the second connecting rod are connected with the inner wall of the tower frame through mounting seats.

Optionally, the first connecting rod and the second connecting rod are respectively connected with the mounting seat through a connecting pin.

According to the wind turbine generator set control method and the wind turbine generator set control system, the rigidity of the tower is dynamically adjusted in real time according to the rotating speed of the wind turbine and the instantaneous natural frequency of the tower, resonance of the tower and the wind turbine is avoided, transient resonance amplitude of non-natural frequency of the tower is reduced, the tower and the wind turbine generator set control system is independent of the wind turbine generator set control system and operates independently, the wind turbine generator set control system is not affected, and power generation loss caused when the rotating speed corresponding to one-.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic structural view of a variable stiffness tower of a wind generating set according to an embodiment of the invention;

FIG. 2 is a schematic structural diagram of a tower stiffness-variable actuator according to an embodiment of the present invention;

FIG. 3 is a schematic flow chart illustrating a method for controlling tower stiffness according to an embodiment of the present invention;

FIG. 4 is a schematic flow chart of another method of tower stiffness control in an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a tower stiffness control device according to an embodiment of the present invention.

Description of reference numerals:

11-wheel speed sensor; 12-a tower vibration acceleration sensor; 13-a tower variable stiffness actuator; 14-a drive controller; 21-a mounting seat; 22-a connecting rod; 23-servo electric cylinder; 24-a lead screw; 25-connecting a pin shaft; 501-an obtaining module; 502-a first control module; 503-second control module.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The embodiment of the invention provides a variable-rigidity tower of a wind generating set, which comprises: the wind wheel rotating speed sensor, the tower vibration acceleration sensor, the tower variable-rigidity executing mechanism and the driving controller.

Referring to the structural schematic diagram of the variable stiffness tower of the wind generating set shown in fig. 1, a wind turbine rotation speed sensor 11, a tower vibration acceleration sensor 12, a tower variable stiffness actuator 13 and a drive controller 14 are shown. The driving controller 14 is connected to the wind turbine rotation speed sensor 11, the tower vibration acceleration sensor 12, and the tower stiffness varying actuator 13, and is configured to receive a signal and control the tower stiffness varying actuator 13 to vary the tower stiffness.

Specifically, the wind wheel rotating speed sensor 11 is configured to collect a wind wheel rotating speed and send the wind wheel rotating speed to the drive controller 14; the tower vibration acceleration sensor is used for acquiring the tower vibration acceleration and sending the tower vibration acceleration to the driving controller 14; the tower rigidity-variable executing mechanism is fixedly arranged in the tower and comprises a movable part, and the movable part is contacted with the inner wall of the tower;

and a driving controller 14 for performing a preset tower stiffness control method and controlling the movable member to move to change the force applied by the movable member to the tower.

The driving controller 14 can process the signals, and a specific tower stiffness control algorithm is adopted to control the movement of the movable component of the tower stiffness changing actuator 13, wherein the movable component is in contact with the inner wall of the tower, and the movement of the movable component can cause the acting force exerted on the inner wall of the tower by the movable component, so that the rigidity of the tower can be changed, the resonance of the tower can be avoided, and the amplitude of the tower can be reduced.

According to the variable-rigidity tower of the wind generating set, the wind wheel rotating speed sensor, the tower vibration acceleration sensor, the tower variable-rigidity executing mechanism and the driving controller are added in the tower of the wind generating set, the rigidity of the tower can be dynamically adjusted according to signals of the sensors, and the natural frequency of the tower is changed, so that the resonance between the tower and a wind wheel is avoided, and the transient resonance amplitude of the non-natural frequency of the tower is reduced; when the tower is designed, whether the natural frequency of the tower is in resonance with the frequency which is one time of that of the wind wheel or not is not particularly considered, so that the weight of the tower can be greatly reduced, and the production and manufacturing cost of the tower is saved.

Optionally, the tower stiffness varying actuator further comprises a servo electric cylinder, and the movable component may be a connecting rod. One end of the connecting rod is connected with the inner wall of the tower through the mounting seat, and the other end of the connecting rod is connected with the top end of a screw rod of the servo electric cylinder. The servo electric cylinder is used for changing the extending length of the lead screw so as to drive the connecting rod to move transversely and change the acting force applied to the inner wall of the tower by the connecting rod.

The mounting seat can be connected with a fixing plate on the inner wall of the tower frame, and an open type connecting lug seat is arranged at one end, far away from the fixing plate, of the mounting seat. One end of the connecting piece is provided with a non-opening connecting lug, and the opening type connecting lug seat is connected with the non-opening connecting lug; the other end of the connecting piece is provided with an opening connecting lug, and the opening connecting lug is connected with a non-opening connecting lug at the top end of the screw rod. Optionally, the open type connecting lug seat of the mounting seat is connected with the non-open type connecting lug of the connecting piece through a connecting pin shaft, and the open type connecting lug of the connecting piece is connected with the non-open type connecting lug at the top end of the screw rod through the connecting pin shaft.

Further, the installation seats can be arranged on the inner wall of the tower in a bilateral symmetry mode, and each tower rigidity-variable actuating mechanism is fixed by the two installation seats.

Further, the variable-rigidity tower of the wind generating set can comprise a first connecting rod and a second connecting rod; the first connecting rod, the servo motor and the second connecting rod are sequentially connected, and the first connecting rod and the second connecting rod are connected with the inner wall of the tower frame through the mounting seat. Optionally, the first connecting rod and the second connecting rod are respectively connected with the mounting seat through a connecting pin shaft.

Optionally, a plurality of tower stiffness-variable actuating mechanisms can be arranged, and all the tower stiffness-variable actuating mechanisms are transversely and fixedly arranged in the tower.

Referring to the structural schematic diagram of the tower stiffness-variable actuator shown in fig. 2, a mounting base 21, a connecting rod 22, a servo electric cylinder 23, a lead screw 24 and a connecting pin 25 are shown.

The mounting seats 21 can be welded on the inner wall of the tower, and each tower rigidity-changing actuating mechanism is fixed through two symmetrically-arranged mounting seats 21. Illustratively, each mounting block 21 is connected to the inner wall of the tower by four steel plates, with open-ended connecting lugs at the ends.

Fig. 2 shows two connecting rods 22, one end of the upper connecting rod 22 is designed with an open connecting lug, and the other end is designed with a non-open connecting lug, the open connecting lug is connected with a screw rod 24 of a servo electric cylinder 23, and the non-open connecting lug is connected with an open connecting lug seat of a fixed seat 21; similarly, the lower connecting rods 22 are connected to the servo electric cylinder 23 and the lower mounting base 21, respectively.

A plurality of tower rigidity changing actuating mechanisms can be installed in one tower, and each servo electric cylinder changes the extending length of a lead screw in the electric cylinder through the rotation of a servo motor, so that the acting force exerted on the inner wall of the tower by the tower rigidity changing actuating mechanisms is changed.

The form of the mounting seat 21 is not limited to that shown in fig. 2, and a similar structural form may be adopted as long as the mounting requirements of the connecting rod are met.

Fig. 3 is a schematic flow chart of a tower stiffness control method in an embodiment of the present invention, applied to a variable stiffness tower of a wind turbine generator system, where the variable stiffness tower of the wind turbine generator system includes a tower stiffness actuator, and the method includes:

s302, acquiring a first-order frequency multiplication frequency of the wind wheel, a tower vibration frequency and a first-order natural frequency of the tower.

Optionally, the continuous transient rotating speed of the wind wheel is obtained through a wind wheel rotating speed sensor, and digital filtering, steady-state processing and band-pass filtering are carried out on the continuous transient rotating speed of the wind wheel to obtain a first frequency multiplication frequency of the wind wheel. And acquiring the vibration acceleration of the tower through a tower vibration acceleration sensor, and performing digital filtering, time domain-frequency domain conversion and band-pass filtering according to the vibration acceleration of the tower to obtain the vibration frequency of the tower. The tower first order natural frequency may be manually entered by a control person.

S304, when the frequency of the wind wheel is one time within a first adjacent interval of the first-order natural frequency of the tower, the tower stiffness changing actuating mechanism is controlled to change the tower stiffness according to the ratio of the first frequency difference to the frequency of the wind wheel. The first frequency difference is the difference between a first-order multiplied frequency of the wind wheel and a first-order natural frequency of the tower.

Optionally, the tower variable stiffness actuator may comprise a servo motor and a moving member, the moving member being transversely mounted inside the tower. The control process for changing the stiffness of the tower can be performed as follows: firstly, determining the rotation angle of a servo motor according to the ratio of a first frequency difference to one-time frequency of a wind wheel; then, the servo motor is controlled to rotate according to the rotation angleSo as to drive the moving member to move transversely to change the rigidity of the tower. Is of f'_r1Representing the first doubling frequency of the wind wheel in f'_tRepresenting tower vibration frequency, in f_t1Representing the tower first order natural frequency, the above-mentioned servomotor rotation angle is determined, for example, as follows:

(1) when f'_r1＜0.85f_t1Or f'_r1＞1.15f_t1When the servo motor is not output, the control signal is not output; when 0.85f_t1≤f′_r1≤1.15f_t1Then, according to | f'_r1-f_t1|/f′_r1Outputting a control signal; when the rotating speed of the wind wheel is reduced to f'_r1＜0.85f_t1In time, in a first preset time period, | f'_r1-f_t1|/f′_r1The control signal linearly decreases to 0; illustratively, the first preset duration is 5 s; when the rotating speed of the wind wheel rises to f'_r1＞1.15f_t1Then | f 'is set within a second preset time length'_r1-f_t1|/f′_r1The control signal linearly decreases to 0; illustratively, the second preset duration is 5 s.

(2) Determining a rotation angle ω of the servo motor according to the control signal, wherein a control function of the rotation angle ω is ω ═ a | f'_r1-f_t1|/f′_r1Wherein A is a gain factor.

According to the rotating speed of the wind wheel and the instantaneous natural frequency of the tower, the rotating angle of the servo motor is dynamically changed in real time, so that the extending length of the lead screw is controlled, the acting force of the connecting rod on the inner wall of the tower is changed, the rigidity of the tower is adjusted, the natural frequency of the tower is changed, and the resonance of the tower and the wind wheel is avoided.

S306, when the one-time frequency of the wind wheel does not fall into the first adjacent interval and the one-time frequency of the wind wheel falls into the second adjacent interval of the tower vibration frequency, the tower rigidity changing executing mechanism is controlled to change the tower rigidity according to the ratio of the second frequency difference to the one-time frequency of the wind wheel. The second frequency difference is the difference between a first frequency multiplication frequency of the wind wheel and the vibration frequency of the tower.

The control process for changing the stiffness of the tower can be performed as follows: firstly, determining the rotation angle of the servo motor according to the ratio of the second frequency difference to the frequency of one time of the wind wheel; and then, controlling the servo motor to rotate according to the rotation angle so as to drive the moving part to move transversely and change the rigidity of the tower. Illustratively, the rotation angle of the servo motor is determined as follows:

(1) when f'_r1＜0.85f_t1Or f'_r1＞1.15f_t1And 0.95 f'_t≤f′_r1≤1.05f′_tThen, according to | f'_r1-f′_t|/f′_r1Outputting a control signal; when the rotating speed of the wind wheel is reduced to f'_r1＜0.95f′_tThen | f 'is set within a third preset time length'_r1-f′_t|/f′_r1The control signal is linearly shifted to 0, illustratively, the third preset duration is 10 s; when the rotating speed of the wind wheel rises to f'_r1＞1.15f′_tThen | f 'is set within a fourth preset time length'_r1-f′_t|/f′_r1The control signal is linearly shifted to 0, illustratively, the fourth preset duration is 10 s.

(2) Determining a rotation angle ω of the servo motor according to the control signal, wherein a control function of the rotation angle ω is ω ═ a | f'_r1-f_t1|/f′_r1Wherein A is a gain factor.

According to the rotating speed of the wind wheel and the instantaneous natural frequency of the tower, the rotating angle of the servo motor is dynamically changed in real time, so that the extending length of the lead screw is controlled, the acting force of the connecting rod on the inner wall of the tower is changed, the rigidity of the tower is adjusted, the natural frequency of the tower is changed, and the transient resonance amplitude of the non-natural frequency of the tower is reduced.

According to the wind turbine generator set control method and the wind turbine generator set control system, the rigidity of the tower is dynamically adjusted in real time according to the rotating speed of the wind turbine and the instantaneous natural frequency of the tower, resonance of the tower and the wind turbine is avoided, transient resonance amplitude of non-natural frequency of the tower is reduced, the tower and the wind turbine generator set control system is independent of the wind turbine generator set control system and operates independently, the wind turbine generator set control system is not affected, and power generation loss caused when the rotating speed corresponding to one-.

When the servo motor is controlled to rotate, the lead screw of the electric servo cylinder is prevented from being too long in extension length so as to leadThe deformation of the tower barrel is too large, the buckling risk is increased, the extending length of the screw rod must be limited, and the maximum value of the extending length is L_lim，L_limThe value of (a) is determined according to the safety margin of the tower tube buckling. Based on this, the above method further comprises: acquiring the maximum length of the transverse movement of the moving part, and determining the maximum rotation angle of the servo motor corresponding to the maximum length; and if the rotation angle determined in the step is larger than the maximum rotation angle, controlling the servo motor to rotate according to the maximum rotation angle.

The following embodiments detail the detailed steps of the tower stiffness control method. Referring to the flow chart of the tower stiffness control method shown in fig. 4, the method comprises the following steps:

s401, collecting data of a wind wheel rotating speed sensor to obtain continuous transient rotating speed n of a wind wheel_r。

S402, aiming at the rotating speed n of the wind wheel_rCarrying out digital filtering processing to eliminate noise signals and other interference signals to obtain the rotation speed n 'of the wind wheel'_r。

S403, wind wheel rotating speed n 'after noise and interference signals are eliminated'_rCarrying out steady state treatment to obtain the frequency f of the steady state wind wheel_r. The stabilization treatment can be carried out on n'_rThe average value is taken after the integration is carried out in a time unit of 0.25 s-0.5 s.

S404, aiming at the steady state wind wheel frequency f_rPerforming band-pass filtering to remove triple frequency and other high-order frequency signals of the wind wheel and only reserve the first double frequency f of the wind wheel'_r1。

S405, collecting data of a tower vibration acceleration sensor arranged at the top of the tower to obtain tower vibration acceleration a_t。a_tIs a continuous time domain signal.

S406, the vibration acceleration a of the tower is treated_tCarrying out digital filtering processing to eliminate noise signals and other interference signals to obtain tower vibration acceleration a'_t。

S407, tower vibration acceleration a'_tCarrying out time domain-frequency domain transformation to obtain the tower vibration frequency f_t. Time-frequency domain transform to pair a'_tPerforming Fast Fourier transform (Fast Fourier Tran)sform，FFT)。

S408, aiming at the tower vibration frequency f_tBand-pass filtering is carried out to remove the vibration excitation frequency of the blade sweep to the tower when the wind wheel rotates and other high-order frequencies to obtain the tower vibration frequency f'_t. The vibration excitation frequency is the triple frequency (3P) frequency of the wind wheel.

S409, inputting a first-order inherent frequency value f of the tower_t1。

So far, all signal acquisition steps are completed, and three groups of signals fed back to the driving controller are as follows: a doubling frequency f'_r1And tower vibration frequency f'_rFirst order natural frequency value f of the tower_t1。

And S410, executing logic for avoiding tower resonance and logic for lightening tower amplitude, and outputting a control signal.

The three groups of signals fed back to the driving controller are processed logically, and the two logics are total, wherein the two logics are respectively used for avoiding tower resonance and lightening tower amplitude, and the specific method is detailed as follows:

avoiding tower resonance logic: when f'_r1＜0.85f_t1Or f'_r1＞1.15f_t1When the servo electric cylinder has no output, the driving controller does not act and does not output a control signal; when 0.85f_t1≤f′_r1≤1.15f_t1At that time, the drive controller is operated according to | f'_r1-f_t1|/f′_r1Outputting a control signal when the rotating speed of the wind wheel is reduced to f'_r1＜0.85f_t1Then drive controller will | f 'within 5 s'_r1-f_t1|/f′_r1The signal is linearly switched to 0, and when the rotating speed of the wind wheel rises, f'_r1＞1.15f_t1Then drive controller will | f 'within 5 s'_r1-f_t1|/f′_r1The signal is linearly up to 0.

Mitigating tower amplitude logic: when f'_r1＜0.85f_t1Or f'_r1＞1.15f_t1And 0.95 f'_r≤f′_r1≤1.05f′_tAt this time, the tower amplitude mitigation logic is activated, and the drive controller is activated according to | f'_r1-f′_t|/f′_r1Outputting a control signal when the rotating speed of the wind wheel is reduced to f'_r1＜0.95f′_tThen the drive controller will | f 'within 10 s'_r1-f′_t|/f′_r1The signal is linearly switched to 0, and when the rotating speed of the wind wheel rises, f'_r1＞1.15f′_tThen the drive controller will | f 'within 10 s'_r1-f′_t|/f′_r1The signal is linearly up to 0.

And S411, the servo electric cylinder driving circuit adjusts the rotation angle omega of the servo motor according to the control signal, and feeds the angle omega value back to the servo electric cylinder driving circuit for closed-loop control.

The control function of the angle ω is ω ═ a ═ f'_r1-f_t1|/f′_r1Wherein A is a gain coefficient, and the total error of the angle omega is not more than 0.1%. When the driving controller has an output signal, when the output signal is increased, the lead screw of the electric servo cylinder is in a stretching state, and when the output signal is reduced, the lead screw of the electric servo cylinder is in a state that the stretching length is gradually reduced.

S412, the servo electric cylinder changes acting force exerted on the tower by the tower rigidity changing actuating mechanism through the extending length of the screw rod, the tower rigidity is improved, and the natural frequency of the tower is changed.

According to the invention, a wind wheel rotating speed sensor, a tower vibration acceleration sensor, a tower rigidity changing actuating mechanism and a driving controller are added in the wind generating set, and the tower rigidity is dynamically adjusted in real time according to the wind wheel rotating speed and the tower instantaneous natural frequency, so that the resonance of the tower and the wind wheel is avoided, and the transient resonance amplitude of the tower non-natural frequency is reduced.

The variable-rigidity tower of the wind generating set provided by the invention has the advantages that the variable-rigidity executing mechanism of the tower is simple in structure and convenient to install and implement. When the tower is erected, whether the natural frequency of the tower is in resonance with the frequency of one time of the wind wheel or not is not particularly considered, so that the weight of the tower can be greatly reduced, and the production and manufacturing cost of the tower is saved.

The traditional method for controlling tower resonance is as follows: the variable pitch yaw brake is controlled, the electromagnetic torque of the generator is adjusted, the generator rapidly passes through a resonance interval, and if the rotating speed corresponding to one-time frequency of the wind wheel frequently fluctuates near the resonance rotating speed, the generating capacity of the wind generating set can be influenced to a great extent. The control method provided by the invention is independent of the main control of the wind generating set, operates independently, and does not influence the main control of the wind generating set, so that the power generation loss caused when the rotating speed corresponding to one-time frequency of the wind wheel fluctuates frequently near the resonance rotating speed is avoided.

Fig. 5 is a schematic structural diagram of a tower stiffness control device applied to a variable stiffness tower of a wind generating set, the variable stiffness tower of the wind generating set comprises a tower stiffness varying actuator, and the device comprises:

the acquiring module 501 is configured to acquire a first-order frequency multiplication frequency of a wind wheel, a tower vibration frequency, and a first-order natural frequency of a tower;

a first control module 502, configured to control the tower stiffness varying actuator to vary the tower stiffness according to a ratio of a first frequency difference to a first frequency multiple of the wind turbine when the frequency multiple of the wind turbine falls within a first proximity range of a first-order natural frequency of the tower; the first frequency difference is the difference between a first-order frequency multiplication frequency of the wind wheel and a first-order natural frequency of the tower;

a second control module 503, configured to control the tower stiffness varying actuator to vary the tower stiffness according to a ratio of a second frequency difference to the first frequency of the wind wheel when the first frequency of the wind wheel does not fall within the first proximity interval and the first frequency of the wind wheel falls within a second proximity interval of the tower vibration frequency; the second frequency difference is a difference between a first frequency multiplication frequency of the wind wheel and a vibration frequency of the tower.

According to the wind turbine generator set control method and the wind turbine generator set control system, the rigidity of the tower is dynamically adjusted in real time according to the rotating speed of the wind turbine and the instantaneous natural frequency of the tower, resonance of the tower and the wind turbine is avoided, transient resonance amplitude of non-natural frequency of the tower is reduced, the tower and the wind turbine generator set control system is independent of the wind turbine generator set control system and operates independently, the wind turbine generator set control system is not affected, and power generation loss caused when the rotating speed corresponding to one-.

Optionally, as an embodiment, the tower stiffness varying actuator includes a servo motor and a moving part, and the moving part is transversely installed inside the tower; the first control module 502 is specifically configured to: determining the rotation angle of the servo motor according to the ratio of the first frequency difference to the one-time frequency of the wind wheel; and controlling the servo motor to rotate according to the rotation angle so as to drive the moving part to move transversely and change the rigidity of the tower.

Optionally, as an embodiment, the wind wheel primary harmonic frequency is f'_r1And said tower has a first order natural frequency of f_t1The first control module 502 is specifically configured to:

when f'_r1＜0.85f_t1Or f'_r1＞1.15f_t1When the servo motor is not output, the control signal is not output; alternatively, the first and second electrodes may be,

when 0.85f_t1≤f′_r1≤1.15f_t1Then, according to | f'_r1-f_t1|/f′_r1Outputting a control signal; alternatively, the first and second electrodes may be,

when the rotating speed of the wind wheel is reduced to f'_r1＜0.85f_t1In time, in a first preset time period, | f'_r1-f_t1|/f′_r1The control signal linearly decreases to 0; alternatively, the first and second electrodes may be,

when the rotating speed of the wind wheel rises to f'_r1＞1.15f_t1Then | f 'is set within a second preset time length'_r1-f_t1|/f′_r1The control signal linearly decreases to 0;

determining a rotation angle omega of the servo motor according to the control signal, wherein a control function of the rotation angle omega is omega-A-f'_r1-f_t1|/f′_r1Wherein A is a gain factor.

Optionally, as an embodiment, the tower stiffness varying actuator includes a servo motor and a moving element, the moving element is transversely installed inside the tower, and the second control module 503 is specifically configured to: determining the rotation angle of the servo motor according to the ratio of the second frequency difference to the frequency of the wind wheel; and controlling the servo motor to rotate according to the rotation angle so as to drive the moving part to move transversely and change the rigidity of the tower.

Optionally, as an embodiment, the wind wheel primary harmonic frequency is f'_r1And said tower has a first order natural frequency of f_t1The second control module 503 is specifically configured to:

when f'_r1＜0.85f_t1Or f'_r1＞1.15f_t1And 0.95 f'_t≤f′_r1≤1.05f′_tThen, according to | f'_r1-f′_t|/f′_r1Outputting a control signal; alternatively, the first and second electrodes may be,

when the rotating speed of the wind wheel is reduced to f'_r1＜0.95f′_tThen | f 'is set within a third preset time length'_r1-f′_t|/f′_r1The control signal is linearly shifted to 0; alternatively, the first and second electrodes may be,

when the rotating speed of the wind wheel rises to f'_r1＞1.15f′_tThen | f 'is set within a fourth preset time length'_r1-f′_t|/f′_r1The control signal is linearly shifted to 0;

determining a rotation angle omega of the servo motor according to the control signal, wherein a control function of the rotation angle omega is omega-A-f'_r1-f_t1|/f′_r1Wherein A is a gain factor.

Optionally, as an embodiment, the apparatus further includes a restriction module, configured to: acquiring the maximum length of the transverse movement of the moving part, and determining the maximum rotation angle of the servo motor corresponding to the maximum length; the control servo motor rotates according to turned angle includes: and if the rotation angle is larger than the maximum rotation angle, controlling the servo motor to rotate according to the maximum rotation angle.

Optionally, as an embodiment, the obtaining module 501 is specifically configured to: acquiring continuous transient rotating speed of a wind wheel through a wind wheel rotating speed sensor, and performing digital filtering, steady-state processing and band-pass filtering on the continuous transient rotating speed of the wind wheel to obtain first frequency multiplication frequency of the wind wheel; the method comprises the steps of obtaining the vibration acceleration of the tower through a tower vibration acceleration sensor, and carrying out digital filtering, time domain-frequency domain conversion and band-pass filtering according to the vibration acceleration of the tower to obtain the vibration frequency of the tower.

The embodiment of the present invention further provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the computer program implements each process of the above-mentioned tower stiffness control method embodiment, and can achieve the same technical effect, and in order to avoid repetition, details are not repeated here. The computer-readable storage medium may be a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk.

Of course, those skilled in the art will understand that all or part of the processes in the methods of the above embodiments may be implemented by instructing the control device to perform operations through a computer, and the programs may be stored in a computer-readable storage medium, and when executed, the programs may include the processes of the above method embodiments, where the storage medium may be a memory, a magnetic disk, an optical disk, and the like.

In this document, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.