JP5705152B2 - Wind power generator - Google Patents

Description

  The present invention relates to a wind turbine generator that converts torque generated by wind turbine blades receiving wind into electric power using a generator.

  With the recent increase in environmental awareness, demand for environmentally friendly clean energy is increasing. One of the representatives of such clean energy is wind power generation. In wind power generation, wind force is converted into torque, and electric power is generated using the torque, so that the load on the environment is small (see, for example, Patent Document 1).

Since the wind power generator is generally installed in a natural environment and basically operates using irregular wind energy as power, relatively large fluctuation torque is applied to the components of the wind power generator. Such torque fluctuations can shorten the life of the components of the wind turbine generator.
Therefore, conventionally, for example, with respect to a change in wind speed, the impact is reduced by pitch control that changes the angle of the windmill blade.

Special table 2008-546948

Under such circumstances, the present inventor has recognized the following problems.
In addition to the above-mentioned change in wind speed, there is a wind shear as a factor of torque fluctuation. Torque fluctuations can occur as the windmill blades rotate while wind shear is occurring. This torque variation can place a mechanical load on the components of the wind turbine generator.

  Conventional pitch control is control for coping with temporal changes in wind speed, and is ineffective against torque fluctuations caused by wind shear.

  In general, it is difficult to reduce torque fluctuation according to the rotation speed of the wind turbine blade by pitch control. This is because the pitch control response is slower than the rotation of the windmill blade.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wind turbine generator that can reduce a mechanical load on components due to a variation in torque caused by wind turbine blades receiving wind.

  One embodiment of the present invention relates to a wind turbine generator. This wind turbine generator is a wind turbine generator that converts torque generated by wind turbine blades receiving wind into electric power using a generator, and is provided with a speed increase provided on a torque transmission path from the wind turbine blades to the generator. And a support member that supports the speed increaser. The rigidity of the support member is set so that the natural frequency of the power transmission system from the windmill blade to the generator deviates from the natural number times the product of the rotational speed of the windmill blade and the number of blades of the windmill blade, and the rotational speed of the windmill blade. Is done.

  According to this aspect, the torque fluctuation according to the rotation speed can be reduced.

  Another embodiment of the present invention is also a wind power generator. This apparatus includes a generator that converts torque generated by wind turbine blades receiving wind into electric power, and a support member that supports the generator. The rigidity of the support member is set so that the natural frequency of the power transmission system from the windmill blade to the generator deviates from the natural number times the product of the rotational speed of the windmill blade and the number of blades of the windmill blade, and the rotational speed of the windmill blade. Is done.

  According to this aspect, the torque fluctuation according to the rotation speed can be reduced.

  Note that any combination of the above elements, or elements and expressions of the present invention that are mutually replaced between apparatuses, methods, systems, and the like are also effective as embodiments of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the mechanical load to the component of a wind power generator by the fluctuation | variation of the torque which arises when a windmill blade receives a wind can be reduced.

It is a side view of the wind power generator concerning a 1st embodiment. FIGS. 2A and 2B are diagrams showing torque fluctuations caused by the wind turbine blade receiving wind. It is a schematic diagram which shows the inside of the nacelle of the wind power generator which concerns on 1st Embodiment. It is a front view of the step-up gear of the wind power generator concerning a 1st embodiment. It is a perspective view of the support mechanism on the right side of the speed up gear shown in FIG. It is a side view of the support mechanism on the right side of the speed up gear shown in FIG. It is a block diagram which shows the function and structure of a control part of FIG. FIGS. 8A and 8B are schematic front views of the step-up gear of the wind turbine generator according to the first embodiment. It is a graph which shows the relationship between the natural frequency of a power transmission system, and the rigidity of a torque arm calculated | required by simulation. It is an exemplary Campbell diagram about the torque in a wind power generator. It is sectional drawing of the left side support mechanism of the step-up gear of the wind power generator which concerns on 2nd Embodiment. It is the sectional view on the AA line of FIG. It is sectional drawing of the left side support mechanism of the step-up gear of the wind power generator which concerns on a 3rd modification.

  Hereinafter, the same or equivalent components and members shown in the respective drawings are denoted by the same reference numerals, and repeated descriptions thereof are omitted as appropriate. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. Also, in the drawings, some of the members that are not important for describing the embodiment are omitted.

(First embodiment)
FIG. 1 is a side view of a wind turbine generator 1 according to the first embodiment. The wind turbine generator 1 includes a column 2 that is erected on a foundation 6, a nacelle 3 that is installed at the upper end of the column 2, and a rotor head 4 that is rotatably assembled to the nacelle 3. . A plurality of (for example, three) wind turbine blades (also referred to as wind turbine blades) 5 are attached to the rotor head 4. The wind turbine generator 1 is a so-called constant speed operation windmill, and is configured such that the windmill blade 5 rotates at the rated rotational speed after the rotational speed of the windmill blade 5 reaches a predetermined rated rotational speed.

  FIGS. 2A and 2B are diagrams showing torque fluctuations caused by wind turbine blades 5 receiving wind. FIG. 2A shows a frequency spectrum of torque, and FIG. 2B shows time series data of torque. By analyzing the torque data represented by FIGS. 2A and 2B, the present inventor has come up with the following two types of torque fluctuations to be reduced.

(1) Torque fluctuation due to rotation of the windmill blade 5 The torque fluctuation is often steady, that is, the frequency is substantially constant. For example, in the frequency spectrum of FIG. 2A, peaks are seen in the primary component 30, the tertiary component 32, and the sixth component 34 corresponding to the rated rotational speed of the wind turbine blade 5. The primary component 30 is centered on the rated speed. The tertiary component 32 is approximately centered on the product of the rated speed and the number of blades (= 3), and the sixth order component 34 is approximately centered on twice the product of the rated speed and the number of blades (= 3). The fact that no peak is observed in the secondary component or the quaternary component is understood from the fact that the windmill blade 5 is approximately three-fold symmetric (that is, it overlaps itself when rotated 120 degrees).

The inventor has found the following relationship between the rotational speed of the wind turbine blade 5 and the torque fluctuation. When the rotation speed of the windmill blade 5 is N, the number of blades of the windmill blade is n, and P is a natural number, peaks in N and nNP tend to appear in the frequency spectrum of torque. Such a peak occurs due to wind shear. That is, the torque fluctuates due to the non-uniform wind speed on the wind receiving surface of the wind power generator 1, and such torque fluctuations appear as peaks in N and nNP.
If the torque fluctuation and the natural frequency of the system overlap, resonance may occur and the mechanical load on the components of the wind power generator 1 may further increase.

(2) Sudden torque fluctuation due to gusts, etc. For example, in the time-series data of FIG. 2B, in addition to the fine torque fluctuation corresponding to the primary component 30, the tertiary component 32, and the sixth component 34, Long time span torque fluctuations. In particular, in the portions 36, 38, and 40 surrounded by a broken line in FIG. 2B, the torque increases with a rise time of about 10 to 20 seconds.

  In the wind turbine generator 1 according to the present embodiment, the following three approaches are adopted in order to effectively reduce the mechanical load on the components of the gearbox due to the two types of torque fluctuations.

  (A) An actuator is introduced into the torque arm that supports the gearbox, and the actuator is actively controlled according to the torque. According to this approach, the mechanical load due to sudden torque fluctuations mainly due to gusts or the like is reduced.

  (B) Two types of torque fluctuation reducing means for steady fluctuation and sudden fluctuation will be introduced. According to this approach, more precise torque fluctuation reduction control is possible based on the inventor's recognition that there are two types of torque fluctuations to be reduced. The idea is to perform necessary control when necessary.

(Ii) An elastic body is provided between the torque arm and the nacelle 3 to attenuate or reduce the torque fluctuation itself due to the rotation of the windmill blade 5. In addition, the rigidity of the elastic body is determined so that the rotation of the windmill blade 5 and the power transmission system from the windmill blade 5 to the generator do not resonate. The rigidity of the elastic body is determined by the natural frequency of the power transmission system.
(A) the rotational speed of the windmill blade 5 (N), and (B) a natural number times the product of the rotational speed of the windmill blade 5 and the number of blades of the windmill blade 5 (nNP),
Set to deviate from

  More specifically, in the frequency spectrum of torque, the frequency range corresponding to the peak approximately centered on the rated speed and the frequency corresponding to the peak approximately centered on the natural number times the product of the rated speed and the number of blades. The rigidity of the elastic body is determined so that the natural frequency does not enter the range. The frequency range corresponding to the peak may be the full width at half maximum (FWHM) of the peak.

  In the example of FIG. 2A, the natural frequency of the power transmission system is equal to or lower than the lower limit of the frequency range corresponding to the primary component 30, or the natural frequency 42 of the power transmission system corresponds to the primary component 30. The upper limit of the frequency range corresponding to the third order component 32 or the lower limit of the frequency range corresponding to the third order component 32 or the upper limit of the frequency range corresponding to the third order component 32 and the sixth order component. The rigidity of the elastic body is determined so as to be between the lower limits of the frequency range corresponding to 34. According to this approach, the mechanical load due to steady torque fluctuation mainly due to the rotation of the wind turbine blade 5 is reduced.

  FIG. 3 is a schematic diagram showing the inside of the nacelle 3. The wind turbine generator 1 converts the torque Qf generated when the windmill blade 5 receives the wind 7 into electric power by the generator 20. The step-up gear 10 is included in the power transmission system, and is provided on a torque transmission path from the windmill blade 5 to the generator 20. The rotor head 4 and the speed increaser 10 are mechanically connected by an input shaft 12, and the input torque Qin (= torque Qf) is input to the speed increaser 10 in the form of rotation of the input shaft 12.

The speed increaser 10 and the generator 20 are mechanically connected by an output shaft 14. The speed increaser 10 rotates the output shaft 14 at an output torque Qout lower than the input torque Qin input via the input shaft 12 and at a higher rotational speed than the rotational speed of the input shaft 12.
The generator 20 generates electricity using the rotation of the output shaft 14.

  The difference (Qin−Qout) between the input torque Qin and the output torque Qout generates a main body torque Qb that attempts to rotate the main body of the gearbox 10 around the input shaft 12. Therefore, the wind turbine generator 1 has a support mechanism 100 that mechanically supports the gear box 10 with respect to the nacelle 3. The support mechanism 100 can withstand the body torque Qb, that is, increase the reaction force from the nacelle 3. It is transmitted to the speed machine 10.

  The support mechanism 100 includes a first arm 110 and a second arm 112 respectively attached to the left and right sides of the speed increaser 10 when the speed increaser 10 is viewed from the input shaft 12 side, and the first arm 110 and the nacelle 3. The first bush 102 and the first actuator 104 provided in series between the second arm 112 and the nacelle 3, and the second bush 106 and the second actuator 108 provided in series between the second arm 112 and the nacelle 3.

  The first bush 102 and the second bush 106 constitute mitigation means for reducing torque fluctuation generated based on wind shear among torque fluctuations applied to the power transmission system. Both the first bush 102 and the second bush 106 are formed of a relatively low-rigidity material such as rubber for shock absorption. As described above, the rigidity of the bush is set such that the natural frequency of the power transmission system deviates from the natural number times the product of the rated rotational speed and the number of blades and from the rated rotational speed.

  The first actuator 104 and the second actuator 108 constitute mitigation means for reducing torque fluctuations not caused by wind shear among torque fluctuations applied to the power transmission system. The first actuator 104 and the second actuator 108 are configured to be able to control the attitude of the speed increaser 10 with respect to the input shaft 12.

  The control unit 114 provided in the wind turbine generator 1 includes a first actuator 104 and a second actuator so that the speed increaser 10 is tilted according to the rotation direction of the input shaft 12 based on information related to the magnitude of the torque Qf. 108 is controlled. Each of the first actuator 104 and the second actuator 108 may be a linear actuator such as a hydraulic cylinder or an air cylinder.

  FIG. 4 is a front view of the gearbox 10. FIG. 5 is a perspective view of a support mechanism on the right side of the gearbox 10 shown in FIG. FIG. 6 is a side view of the support mechanism on the right side of the gearbox 10 shown in FIG.

  A first accelerometer 120 is attached to the first arm 110, and a second accelerometer 122 is attached to the second arm 112. The first accelerometer 120 and the second accelerometer 122 measure the acceleration of the first arm 110 and the second arm 112, respectively. The acceleration measured by these accelerometers is a value reflecting the magnitude of the torque Qf at the time of measurement, excluding the contribution from the first actuator 104 and the second actuator 108. That is, basically, when the torque Qf increases, the measured acceleration increases, and when the torque Qf decreases, the measured acceleration decreases.

  Regarding the support mechanism on the right side of the speed increaser 10, one end of the first arm 110 is attached to the main body of the speed increaser 10, and the other end is separated along a direction along the input shaft 12 (hereinafter referred to as a main shaft direction). Two rectangular ring portions 110a and 110b are provided. The base portions 110aa and 110ba of the two rectangular ring portions 110a and 110b are inserted into the inner peripheral surface 116a side of the first bush holding portion 116, which is a rectangular ring-shaped member.

  On the inner peripheral surface 116 a side of the first bush holding portion 116, the bottom portions 110 aa and 110 ba are sandwiched between the upper and lower first bushes 102. The two first bushes 102 are attached to the inner peripheral surface 116 a of the first bush holding portion 116. The first bush holding unit 116 holds a total of four first bushes 102. Similarly, for the support mechanism on the left side of the gearbox 10, a second bush holding portion 118 that holds a total of four second bushes 106 is provided.

  The first actuator 104 and the second actuator 108 are disposed so as to be substantially symmetrical with respect to the input shaft 12. The first actuator 104 and the second actuator 108 are driven in opposite directions as a result of the control by the control unit 114. That is, when the first actuator 104 moves the first bush holding portion 116 vertically upward, the second actuator 108 moves the second bush holding portion 118 vertically downward. In this case, the speed increaser 10 tilts counterclockwise around the input shaft 12 when viewed from the front.

  It depends on the direction of rotation of the input shaft 12 to which the gearbox 10 is inclined. That is, the first actuator 104 and the second actuator 108 tilt the speed increaser 10 clockwise (counterclockwise) when the input shaft 12 rotates clockwise (counterclockwise) when viewed from the front.

  Referring to FIGS. 5 and 6, the first actuator 104 includes a first front actuator 104 a and a first rear actuator 104 b, and supports the first bush holding portion 116 at two locations spaced along the main axis direction. The first front actuator 104a supports the first bush holding portion 116 with respect to the nacelle 3 on the front side of the gearbox 10, and the first rear actuator 104b holds the first bush holding portion 116 on the back side of the gearbox 10. Supports the nacelle 3. When the first bush holding portion and the first bush are viewed as a part of the first arm, the other end of the first arm is attached to the first actuator 104, and the first actuator 104 is separated at two locations along the input shaft 12. It can be said that the first arm is supported. The second actuator 108 has a similar configuration.

  FIG. 7 is a block diagram showing the function and configuration of the control unit 114. Each block shown here can be realized in hardware by elements and mechanical devices such as a microcomputer and a CPU (central processing unit) of a computer, and in software it is realized by a computer program or the like. Then, the functional block realized by those cooperation is drawn. Therefore, it is understood by those skilled in the art who have touched this specification that these functional blocks can be realized in various forms by a combination of hardware and software.

The control unit 114 includes a measurement result acquisition unit 130, a wind speed acquisition unit 132, a mode selection unit 134, and a tilt drive unit 136.
The measurement result acquisition unit 130 acquires acceleration measurement results from the first accelerometer 120 and the second accelerometer 122.
The wind speed acquisition unit 132 acquires the wind speed measured by an anemometer arranged in a mesh around the wind power generator 1.

  The mode selection unit 134 controls the first actuator 104 and the second actuator 108 based on at least one of the acceleration measurement result acquired by the measurement result acquisition unit 130 and the wind speed acquired by the wind speed acquisition unit 132. Select. The control mode includes a sudden torque control mode corresponding to a sudden increase in the torque Qf and a steady torque control mode during steady operation.

  In particular, the mode selection unit 134 removes contributions from the first actuator 104 and the second actuator 108 from the measured acceleration. The mode selection unit 134 compares the magnitude of the acceleration thus processed with a predetermined acceleration threshold value. The mode selection unit 134 selects the sudden torque control mode when the former is larger than the latter, and selects the steady torque control mode otherwise. During this comparison, the mode selection unit 134 may perform correction based on the measured wind speed. The acceleration threshold corresponds to the torque threshold Qth of the torque Qf, and when the magnitude of acceleration from which the contribution by the actuator is removed is larger than the acceleration threshold, the magnitude of the torque Qf is the torque threshold. This corresponds to the case of exceeding Qth.

When the mode selection unit 134 selects the sudden torque control mode, the tilt drive unit 136 specifies the rotation direction of the input shaft 12 from the acceleration directions measured by the first accelerometer 120 and the second accelerometer 122. To do. The tilt drive unit 136 follows the specified rotation direction (in other words, “so that the speed increaser 10 tilts in the same direction as the rotation direction of the input shaft 12”) or “in a direction in which the torque is reduced”. The driving directions of the first actuator 104 and the second actuator 108 are determined. For example, when the rotation direction of the specified input shaft 12 is clockwise (counterclockwise) when viewed from the front of the speed increaser 10, the driving direction of the first actuator 104 is vertically downward (vertically upward), the second The driving direction of the actuator 108 is determined to be vertically upward (vertically downward). The tilt driving unit 136 drives each actuator at a predetermined speed in the determined direction. The driving speed of the first actuator 104 is set to be equal to the driving speed of the second actuator 108.
In addition, when the direction of rotation of the windmill blade 5 is determined, the inclination driving unit 136 does not need to specify the direction of rotation each time. In this case, the tilt driving unit 136 may determine the driving directions of the first actuator 104 and the second actuator 108 so as to follow the determined rotation direction.

  Each actuator has an upper limit value of the expansion / contraction amount based on the limit value of the expansion / contraction amount. When at least one of the expansion / contraction amount of the first actuator 104 and the expansion / contraction amount of the second actuator 108 reaches a corresponding upper limit value, the tilt driving unit 136 causes the first actuator 104 and the second actuator 108 to expand / contract at that time. Control the amount to be maintained.

  When the mode selection unit 134 selects the steady torque control mode, the tilt drive unit 136 does not control the first actuator 104 and the second actuator 108. That is, the tilt driving unit 136 puts the first actuator 104 and the second actuator 108 into a non-control state. In this uncontrolled state, the first actuator 104 and the second actuator 108 have a buffering action against the rotation of the main body of the gearbox 10 around the input shaft 12. For example, hydraulic cylinders and air cylinders respond elastically to external forces when not controlled. The first actuator 104 and the second actuator 108 may realize a buffering action using the elasticity of the cylinder.

  When the sudden torque control mode is switched to the steady torque control mode, the first actuator 104 and the second actuator 108 attempt to return to the equilibrium position, that is, the position where the expansion / contraction amount is zero.

Operation | movement of the wind power generator 1 comprised as mentioned above is demonstrated.
FIGS. 8A and 8B are schematic front views of the gearbox 10. FIG. 8A shows the state of the gearbox 10 when the steady torque control mode, ie, torque Qf <torque threshold Qth, and FIG. 8B shows the sudden torque control mode, ie, torque Qf ≧ torque threshold. The state of the gearbox 10 at the value Qth is shown.

  In the steady torque control mode, the first actuator 104 and the second actuator 108 are in a non-control state (a state in which they are fixed so as not to move), and support the first arm 110 and the second arm 112 in an equilibrium position. Due to the buffering action of the first actuator 104 and the second actuator 108, the fluctuation of the main body torque Qb is moderated. In other words, the uncontrolled first actuator 104 and second actuator 108 act as a low-pass filter for the body torque Qb.

  In the sudden torque control mode, the first actuator 104 and the second actuator 108 are driven so that the speed increaser 10 tilts according to the direction of rotation of the input shaft 12. In the example of FIG. 8B, since the input shaft 12 rotates clockwise, the first actuator 104 contracts at a predetermined speed and the second actuator 108 extends at the same speed. As a result, the speed increaser 10 tilts clockwise around the input shaft 12.

  According to the wind turbine generator 1 according to the present embodiment, when the torque Qf increases, the speed increaser 10 tilts according to the direction of rotation of the input shaft 12. Thereby, increase of the torque which acts on the power transmission system of the gearbox 10 by increase of the torque Qf can be suppressed. As a result, the lifetime of the gearbox 10 can be extended.

  In general, a wind turbine blade of a wind turbine generator may be momentarily strongly applied with a “wind whose wind speed or direction changes”. For example, when a strong gust is applied to the windmill blade, a strong acceleration torque is instantaneously applied to each element of the speed increaser. However, since a generator that rotates at high speed is connected as a load at the tip of the speed increaser, each element of the speed increaser can instantaneously follow this acceleration torque due to inertia and increase the rotation speed. Can not. As a result, when the acceleration torque rises steeply, the acceleration torque that rises steeply is applied to each element instantaneously (as is applied to each stationary element).

  Therefore, the wind turbine generator 1 according to the present embodiment, based on the measurement results of the first accelerometer 120 and the second accelerometer 122, should be used from among the sudden torque control mode and the steady torque control mode. Select a mode. When the acceleration torque rises as described above, the wind turbine generator 1 selects the sudden torque control mode. In the sudden torque control mode, the main body of the speed increaser 10 is tilted in accordance with the direction of rotation of the input shaft 12. Therefore, the acceleration torque applied to each element of the speed increaser 10 can be reduced by the amount of inclination of the speed increaser 10 main body.

  In the wind power generator 1 according to the present embodiment, the first actuator 104 and the second actuator 108 are controlled based on the wind speed measured by the anemometer provided around the wind power generator 1. Therefore, more accurate actuator control is possible.

  Further, in the wind turbine generator 1 according to the present embodiment, each actuator supports the corresponding bush holding portion at two locations separated along the input shaft 12. Therefore, the resistance to bending of the input shaft 12, in particular, an external force that causes the input shaft 12 to swing along the vertical plane is improved.

  In the wind turbine generator 1 according to the present embodiment, the actuator that has expanded or contracted in the sudden torque control mode tends to return to the original equilibrium position in the steady torque control mode. Therefore, in a situation where the amount of expansion / contraction of the actuator is limited, sudden torque fluctuations can be suppressed more efficiently.

  Further, in the wind turbine generator 1 according to the present embodiment, the rigidity of the bush is set so that the natural frequency of the power transmission system does not fall within the frequency range corresponding to the peak of the torque frequency spectrum. Accordingly, the rotation of the windmill blade 5 and the resonance between the power transmission system can be suppressed. As a result, the mechanical load applied to the power transmission system can be reduced and the life of the power transmission system can be extended.

  Further, the wind turbine generator 1 according to the present embodiment is caused by the wind shear among the torque fluctuations applied to the power transmission system and the means for reducing torque fluctuations generated based on the wind shear among the torque fluctuations applied to the power transmission system. Both of the means for reducing torque fluctuations are not provided. Therefore, it is possible to suitably cope with both steady fluctuations and sudden fluctuations in torque. Further, by properly using both, it is possible to perform more precise torque fluctuation reduction control.

(Second Embodiment)
In 1st Embodiment, the case where the wind power generator 1 was a constant speed driving | running | working windmill was demonstrated. The wind turbine generator according to the second embodiment is a so-called variable speed operation wind turbine, and is configured such that the rotation speed of the wind turbine blade 5 is changed depending on the wind speed or the like during normal operation.

  FIG. 9 is a graph showing the relationship between the natural frequency of the power transmission system and the rigidity of the torque arm, obtained by simulation. As shown in FIG. 9, the natural frequency of the power transmission system is relatively largely dependent on the rigidity of the torque arm. Therefore, the natural frequency can be controlled with relatively high accuracy by changing the rigidity of the torque arm.

  FIG. 10 is an exemplary Campbell diagram for torque in a wind turbine generator. FIG. 10 particularly relates to a three-blade wind power generator. In the case of a constant-speed operation wind turbine such as the wind turbine generator 1 according to the first embodiment, when the wind turbine generator is started, the rotational speed of the wind turbine blade rises relatively quickly from 0 to the rated rotational speed Na (arrow 302). ). Thereafter, the rotational speed is stabilized near the rated rotational speed Na (arrow 304). In this case, the rigidity of the torque arm is such that the natural frequency fd of the power transmission system is a value f3 between the product (3Na) of the rated rotational speed Na and the number of blades and twice the product (6Na). Is set. Even if the natural frequency fd overlaps with a higher-order component (6N or 12N) while the rotational speed is increasing, the increase speed of the rotational speed is large, so that the increase in torque fluctuation due to resonance is relatively limited. Therefore, the necessity of actively changing the rigidity of the torque arm according to the rotational speed is relatively low, and the natural frequency fd can be set to a value that does not depend on the rotational speed. Thereby, the structure of the means to reduce the torque fluctuation generated based on the wind shear can be simplified.

  In the case of a variable speed operation wind turbine such as the wind turbine generator according to the second embodiment, the rotational speed can fluctuate relatively large during normal operation (arrow 306). Therefore, if the natural frequency is constant regardless of the rotation speed, a state in which the natural frequency overlaps with a higher-order component may continue for a relatively long time. Therefore, the wind turbine generator according to the second embodiment measures the rotational speed of the windmill blade 5 and determines the rigidity of the torque arm by the rotational speed at which the natural frequency fv of the power transmission system is measured and the number of blades. Control to deviate from natural product multiple of product and measured rotation speed.

  In the example of FIG. 10, when the rotation speed is in the range of 0 to Nb, the natural frequency fv is set to f1. At this time, f1> 12Nb. When the rotation speed is in the range of Nb to Nc, the natural frequency fv is set to f2. At this time, f1> f2> 6Nc. When the rotation speed is in the range of Nc to Na, the natural frequency fv is set to f3.

  FIG. 11 is a cross-sectional view of the support mechanism on the left side of the step-up gear of the wind turbine generator according to the second embodiment. The cross section of FIG. 11 is orthogonal to the principal axis direction. 12 is a cross-sectional view taken along line AA in FIG. Although not shown in FIGS. 11 and 12, the wind turbine generator includes a tachometer that measures the rotation speed of the windmill blade 5. The tachometer may be attached to the input shaft or output shaft of the gear box, for example. The tachometer may be constructed using known rotation measurement techniques.

  One end of the second arm 212 is attached to the gearbox main body, and the other end is provided with a rectangular ring portion 212a. The bottom portion 212aa of the rectangular ring portion 212a is inserted into the inner peripheral surface side of the second bush holding portion 218. On the inner peripheral surface side of the second bush holding portion 218, the bottom portion 212aa is supported by a support member. The support member is divided into a plurality of, for example, six partial support portions, and each partial support portion is configured to support the base portion 212aa in parallel (or individually).

  The first partial support portion 248 includes a split bush 230 and a state switching portion 246 interposed between the split bush 230 and the bottom portion 212aa. In response to a command from the control unit (not shown), the state switching unit 246 switches the state of the first partial support unit 248 between the support state related to the support of the speed increaser and the state that is not related to the support of the speed increaser. Switch between supporting state.

The state switching part 246 includes a fixed part 242 fixed to the divided bush 230, a movable part 244 interposed between the fixed part 242 and the bottom side part 212aa, and a rigidity switch for taking in and out the movable part 244 according to a command from the control part. And an actuator 250. When the movable portion 244 is pulled out by the rigidity switching actuator 250, the divided bush 230 does not transmit force from the second arm 212 to the nacelle 3. When the movable portion 244 is inserted by the rigidity switching actuator 250, the divided bush 230 transmits a force from the second arm 212 to the nacelle 3, and the rigidity of the divided bush 230 contributes to the rigidity of the second arm 212.
The other five partial support portions are configured in the same manner as the first partial support portion 248.
The support mechanism on the right side of the speed increaser of the wind turbine generator is configured in the same manner as the support mechanism on the left side. That is, in the second embodiment, there are a total of 12 partial support portions.

  The control unit measures the rigidity of the support member by the natural speed fv of the power transmission system, which is a natural number times the product of the rotational speed measured by the tachometer and the number of blades of the windmill blade 5, and by the tachometer. Control to deviate from the rotation speed. In particular, the control unit discretely controls the rigidity of the support member by controlling the number of partial support units that are in the support state.

  For example, in order to realize the change of the natural frequency fv with respect to the rotational speed as shown in FIG. Let the partial support part be a support state. When the measured number of rotations is in the range of Nb to Nc, the control unit pulls out the movable portions of the two partial support portions to be in an unsupported state, and sets the number of partial support portions in the supported state to 10. When the measured number of rotations is in the range of Nc to Na, the control unit pulls out the movable portions of the six partial support portions to be in an unsupported state, and sets the number of partial support portions in the supported state to 6.

  In the wind turbine generator according to the present embodiment, the rigidity of the support member is set to active so that the natural frequency fv of the power transmission system does not fall within the frequency range corresponding to the peak of the torque frequency spectrum. Therefore, especially in the variable speed driving wind turbine, the rotation of the wind turbine blade 5 and the resonance between the power transmission system can be suppressed. As a result, the mechanical load applied to the power transmission system can be reduced and the life of the power transmission system can be extended.

  Heretofore, the configuration and operation of the wind turbine generator according to the embodiment have been described. It is to be understood by those skilled in the art that these embodiments are exemplifications, and that various modifications can be made to combinations of the respective components, and such modifications are within the scope of the present invention.

  Also, combinations of the embodiments are possible. That is, the second actuator 108 in the first embodiment may be provided between the second bush holding portion 218 and the nacelle 3 in the second embodiment. In this case, active mitigation means for mitigating torque fluctuations generated based on wind shear and active mitigation means for mitigating torque fluctuations not caused by wind shear are provided.

  In the first embodiment, the case where the tilt driving unit 136 does not control the first actuator 104 and the second actuator 108 when the mode selection unit 134 selects the steady torque control mode has been described. Not limited. For example, the tilt drive unit moves the first actuator 104 and the second actuator 108 so that the speed increaser 10 tilts according to the direction of rotation of the input shaft 12 even when the mode selection unit 134 selects the steady torque control mode. You may control. In this case, the inclination driving unit 136 may drive the actuator at a speed smaller than the speed at which the actuator is driven in the sudden torque control mode. That is, the difference in mode may be a difference in speed at which the actuator is driven.

  In the first embodiment, the case where the actuator is introduced into the support mechanism 100 of the gearbox 10 has been described, but the present invention is not limited to this. For example, in the case of a so-called gearless wind power generator, the rotor head and the generator are directly connected by an input shaft. The technical idea of the present embodiment can also be applied to such a wind power generator. The wind turbine generator according to the first modified example converts a torque generated when the windmill blade receives wind into electric power, and receives the generator in the form of rotation of the input shaft, and the attitude of the generator with respect to the input shaft An actuator that can control the generator, and a control unit that controls the actuator so that the generator is tilted according to the direction of rotation of the input shaft based on information related to the magnitude of torque generated by the wind turbine blade receiving wind. Prepare. According to this modification, it is possible to suppress an increase in torque acting on the power transmission system of the generator due to an increase in torque Qf. As a result, the life of the generator can be extended.

A gearless wind turbine generator according to a second modification includes a generator that converts torque generated by wind generated by a windmill blade into electric power, and a support member that supports the generator. The rigidity of the support member is set so that the natural frequency of the power transmission system from the windmill blade to the generator deviates from the natural number times the product of the rotational speed of the windmill blade and the number of blades of the windmill blade, and the rotational speed of the windmill blade. Is done. In this case, the rotation of the windmill blade and the resonance between the power transmission system can be suppressed.
The technical idea of the second embodiment may be applied to a gearless wind power generator.

  In the first embodiment, the description has been given of the case where each actuator supports the corresponding bush holding portion at two positions separated along the main axis direction. However, the present invention is not limited to this, and the actuator may be provided at one position. You may support the corresponding bush holding | maintenance part in three or more places separated along.

  In the first embodiment, the case where acceleration is measured using the first accelerometer 120 and the second accelerometer 122 has been described. However, the present invention is not limited to this, and information related to the magnitude of the torque Qf can be measured. That's fine. For example, a displacement meter may be provided instead of the accelerometer, or a load sensor such as a load cell may be provided. Alternatively, for example, a friction type torque meter may be attached to the input shaft 12. The input torque Qin measured by this torque meter is a torque Qf itself or a quantity having a relatively high relationship with the torque Qf.

  In the first embodiment, the mode selection unit 134 has been described with respect to the case where the measured wind speed is used for correction at the time of acceleration comparison, but the present invention is not limited to this. For example, the mode selection unit may predict the torque Qf from the measured wind speed. The mode selection unit compares the predicted torque Qf with the torque threshold value Qth, selects the sudden torque control mode if the former is larger than the latter, and selects the steady torque control mode otherwise. Also good.

  In the first embodiment, the case where the control unit 114 controls the first actuator 104 and the second actuator 108 based on the magnitude relationship between the magnitude of acceleration and the acceleration threshold value has been described. However, the present invention is not limited to this. . For example, the control unit may determine the expansion / contraction amount of the actuator and the driving speed according to the magnitude of the torque Qf.

  In the first embodiment, the case where the first accelerometer 120 is attached to the first arm 110 and the second accelerometer 122 is attached to the second arm 112 has been described. However, the present invention is not limited to this. May be attached to any part of the support mechanism.

  In the first embodiment, the case where the bush and the actuator are provided in series between the arm and the nacelle has been described. However, the present invention is not limited to this. For example, the bush may not be provided. And the nacelle may be provided in parallel.

  FIG. 13 is a cross-sectional view of the support mechanism on the left side of the step-up gear of the wind turbine generator according to the third modification. The cross section of FIG. 13 is orthogonal to the principal axis direction. The left support mechanism includes a second bush 406 and a second actuator 408 provided in parallel between the second arm 412 and the nacelle 3. The second bush holding portion 418 holds the second bush 406 and is interposed between the second bush 406 and the nacelle 3.

  In the second embodiment, the case where the rigidity switching actuator 250 moves the movable part 244 in and out has been described. However, the present invention is not limited to this, and the rigidity switching actuator may move the divided bush in and out.

  DESCRIPTION OF SYMBOLS 1 Wind power generator, 2 support | pillars, 3 nacelle, 4 rotor head, 5 windmill blade, 6 foundation, 10 speed increaser, 12 input shaft, 20 generator, 100 support mechanism, 102 1st bush, 104 1st actuator, 106 2nd bush, 108 2nd actuator, 110 1st arm, 112 2nd arm, 114 control part.

Claims (6)

A wind turbine generator that converts torque generated by wind turbine blades receiving wind into electric power using a generator,
A speed increaser provided on a path of torque transmission from the windmill blade to the generator;
A support member for supporting the speed increaser,
The rigidity of the support member is such that the natural frequency of the power transmission system from the windmill blade to the generator is a natural number times the product of the number of rotations of the windmill blade and the number of blades of the windmill blade, and It is set so that it may remove from rotation speed, The wind power generator characterized by the above-mentioned. The wind turbine generator is configured such that the wind turbine blade rotates at the rated rotational speed after the rotational speed of the wind turbine blade reaches a predetermined rated rotational speed.
The rigidity of the support member is set such that the natural frequency of the power transmission system deviates from a natural number multiple of a product of a rated rotational speed and the number of blades of the wind turbine blade and a rated rotational speed. Item 1. The wind power generator according to Item 1. A measuring unit for measuring the rotational speed of the windmill blade;
For the rigidity of the support member, the natural frequency of the power transmission system is a natural number times the product of the number of rotations measured by the measurement unit and the number of blades of the windmill blade, and the number of rotations measured by the measurement unit. The wind power generator according to claim 1, further comprising: a rigidity control unit that controls to disengage from the wind power generator. The support member includes a plurality of partial support parts configured to take a first state or a second state that is not involved in supporting the speed increaser;
The wind power generator according to claim 3, wherein the stiffness control unit controls the stiffness of the support member by controlling the number of partial support units taking the first state.   The rigidity of the support member is set so that the natural frequency of the power transmission system is between the product of the number of rotations of the wind turbine blade and the number of blades of the wind turbine blade and twice the product. The wind power generator according to any one of claims 1 to 4, wherein A generator that converts torque generated by windmill blades receiving wind into electric power;
A support member for supporting the generator,
The rigidity of the support member is such that the natural frequency of the power transmission system from the windmill blade to the generator is a natural number times the product of the number of rotations of the windmill blade and the number of blades of the windmill blade, and It is set so that it may remove from rotation speed, The wind power generator characterized by the above-mentioned.

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