JP2013231409A - Wind power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wind power generator capable of correctly monitoring the vibration of blades on a real time basis.SOLUTION: A wind power generator 1 includes a turning mechanism having a hub 5, and a plurality of blades 2_1 to 2_3 arranged in a radial manner around the rotary shaft 8 of the hub 5, a nacelle 6 having a generator driven by the turning mechanism, a tower 7 for supporting the nacelle 6, strain gages 3_1, 4_1 which are provided on at least one of the plurality of blades 2_1 to 2_3, and arranged in series in the longitudinal direction of the blades 2_1 to 2_3, and a vibration calculation unit for calculating the vibration component of the primary mode of the blade 2_1 and the secondary mode thereof by using signals outputted from the strain gages 3_1, 4_1.

Description

  The present invention relates to a wind power generator, and more particularly to a wind power generator capable of monitoring blade vibration.

  In recent years, interest in power generation devices using clean energy has increased. One such power generator is a wind power generator. The wind turbine generator includes a windmill that rotates by receiving natural wind, a generator that converts the rotation of the windmill into electric power, and the like.

  Patent Document 1 discloses a technique for preventing contact between a blade and a tower included in a wind turbine generator.

US Patent Application Publication No. 2004/0057828

  The wind power generator includes a rotating mechanism (windmill) that rotates by receiving natural wind, and a generator that converts rotation of the rotating mechanism into electric power. The rotation mechanism includes a hub and a plurality of blades arranged radially around the rotation axis of the hub. Moreover, the generator is accommodated in the nacelle, and the nacelle is supported by the tower.

  In a wind turbine generator having such a configuration, the blade may vibrate due to strong wind or wind pulsation. In particular, when the blade resonates, the vibration of the blade increases, which causes a problem that the blade fatigues and breaks, or the blade contacts the tower. Therefore, a wind turbine generator capable of accurately monitoring blade vibration in real time has been required.

  In view of the above problems, an object of the present invention is to provide a wind turbine generator capable of accurately monitoring blade vibration in real time.

  A wind turbine generator according to the present invention includes a rotating mechanism including a hub and a plurality of blades arranged radially around the rotation axis of the hub, a nacelle including a generator driven by the rotating mechanism, and the nacelle. A first tower and a second strain gauge provided on at least one of the plurality of blades and arranged in series in the longitudinal direction of the blade, and the first and second strain gauges A vibration calculation unit that calculates a vibration component of a primary mode and a vibration component of a secondary mode of the blade using a signal output from the blade.

  According to the present invention, it is possible to provide a wind turbine generator capable of accurately monitoring blade vibration in real time.

1 is a front view showing a wind turbine generator according to Embodiment 1; It is a side view which shows the wind power generator concerning Embodiment 1. FIG. It is a figure for demonstrating a mode test apparatus. It is a figure which shows the vibration of the mode test apparatus shown in FIG. It is a figure which shows the relationship between the measured value of a primary mode, and an interpolation function. It is a figure which shows the relationship between the measured value of a secondary mode, and an interpolation function. It is a figure which shows the case where the interpolation function of a primary mode is subjected to second-order differentiation. It is a figure which shows the case where the interpolation function of a secondary mode is second-order differentiated. It is a block diagram which shows the control system with which the wind power generator concerning Embodiment 1 is provided. 3 is a flowchart for explaining an operation of the wind turbine generator according to the first embodiment; It is a block diagram which shows the control system with which the wind power generator concerning Embodiment 2 is provided. It is a figure for demonstrating the wind power generator used for experiment. It is a figure for demonstrating the bending direction of a braid | blade. It is a figure which shows the time change of the displacement of a blade front-end | tip (when there is no board in front of a tower). It is a figure which shows the time change of the displacement of a blade front-end | tip (when there exists a board ahead of a tower).

<Embodiment 1>
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a front view illustrating the wind turbine generator according to the first embodiment. FIG. 2 is a side view of the wind power generator according to the first embodiment. As shown in FIGS. 1 and 2, the wind turbine generator 1 according to the present embodiment includes a rotating mechanism including blades 2_1 to 2_3 and a hub 5, a nacelle 6, and a tower 7.

  The blades 2_1 to 2_3 are arranged radially around the rotation axis 8 of the hub 5. The blades 2_1 to 2_3 have a pitch angle with respect to the wind inflow direction so that the force of the wind flowing toward the wind power generator 1 can be converted into a rotational force. The rotating mechanism including the blades 2_1 to 2_3 and the hub 5 is arranged so that the rotating shaft 8 is substantially horizontal during normal operation of the wind turbine generator. The wind power generator 1 shown in FIG. 1 shows a case where the three blades 2_1 to 2_3 are arranged radially at intervals of 120 degrees, but the number of blades may be two, or four. There may be more than one.

  The hub 5 is mechanically connected to a generator provided in the nacelle 6, and the generator converts the rotational force transmitted from the hub 5 into electric power. The hub 5 and the generator may be mechanically connected via a gear (transmission). In this case, a gear box is disposed in the nacelle 6. The tower 7 supports the nacelle 6 at the top of the tower 7.

  Moreover, in the wind power generator 1 concerning this Embodiment, the two strain gauges 3_1 to 3_3 and 4_1 to 4_3 are provided in each blade 2_1 to 2_3. In the wind turbine generator 1 according to the present embodiment, two strain gauges 3_1 and 4_1 are arranged in series in the longitudinal direction of the blade 2_1 in order to measure the vibration in the longitudinal direction of the blade.

  In the wind power generator 1 shown in FIG. 1, the case where two strain gauges are provided for all the blades 2_1 to 2_3 is shown, but the strain gauge may be provided for at least one of the plurality of blades. Good. Moreover, since the wind turbine generator 1 according to the present embodiment measures two vibration modes (primary mode and secondary mode) of the blade, it is necessary to provide at least two strain gauges on one blade. At this time, three or more strain gauges may be provided on one blade. By increasing the number of strain gauges, blade vibration can be measured more accurately.

  A strain gauge is a sensor that utilizes the fact that the cross-sectional area of a metal resistor changes when stress acts in the longitudinal direction of the metal resistor, and the resistance of the metal resistor changes accordingly. Strain gauges are inexpensive and robust, making them suitable for applications that detect blade strain. Each of the strain gauges 3_1 to 3_3, 4_1 to 4_3 is attached so that the strain in the longitudinal direction of the blades 2_1 to 2_3 can be measured. For example, the strain gauges 3_1 to 3_3, 4_1 to 4_3 may be provided on the surface of the blades 2_1 to 2_3 (the upstream surface in the wind direction) (see FIG. 2), and the back surface of the blades 2_1 to 2_3 (the downstream in the wind direction). May be provided on the side surface). Further, the strain gauges 3_1 to 3_3, 4_1 to 4_3 may be embedded in the blade. When the blade vibrates in a direction parallel to the rotation shaft 8, the distortion on the front surface and the back surface is larger than that in the blade. Therefore, the strain gauges 3_1 to 3_3, 4_1 to 4_3 are preferably provided on the front surface or the back surface of the blades 2_1 to 2_3.

  In this embodiment, the case where the strain of the blade is measured using a strain gauge using a metal resistor has been described. However, the strain of the blade may be measured using a piezoelectric element instead of the strain gauge. Good.

  Next, a method for calculating the primary mode vibration and the secondary mode vibration of the blade using the signal output from the strain gauge will be described. In the wind turbine generator 1 according to the present embodiment, the vibration component of both the first mode vibration component and the second mode vibration component are calculated from the strain obtained by the strain gauge using the inverse transformation matrix. It is possible to monitor the deformation of the entire blade in real time as a superposition of the two.

When considering the primary mode and the secondary mode, the displacement of the blade can be approximated by the following equation.

Here, z _d is an arbitrary position of the blade, ν (z _d , t) is a displacement of the position z _d at time t, and V ₁ (z _d ) is a value of the mode shape at the position z _d expressed by an interpolation function. (Primary mode), f ₁ (t) is the time response of the contribution factor component of the primary mode form, and V ₂ (z _d ) is the value of the mode form at the position z _d (second order mode) expressed by an interpolation function. , F ₂ (t) is the time response of the contribution factor component of the second-order mode.

In this case, two strain gauges are required to obtain the displacement ν (z _d , t). If the positions z ₁ and z ₂ are measurement positions using a strain gauge, the relationship between strain and displacement can be expressed as follows.

Here, ε ₁ (z ₁ , t) is the strain at time t at position z ₁ , ε ₂ (z ₂ , t) is the strain at time t at position z ₂ , and r ₁ is the central axis of the blade at position z ₁ To the surface to which the first strain gauge is attached (neutral line distance), r ₂ is the distance from the central axis of the blade at the position z ₂ to the surface to which the second strain gauge is attached.

Therefore, the time responses in the first-order mode and the second-order mode calculated from the distortions measured at the positions z ₁ and z ₂ can be expressed as follows from Equations 2 and 3.

Therefore, the displacement at the position z _d can be expressed as follows by substituting Equation 4 into Equation 1.

  Here, each coefficient of Formula 5 can be obtained by a mode test. Below, the determination method of each coefficient is demonstrated.

  FIG. 3 is a diagram for explaining the mode test apparatus. In the mode test described below, a blade 11 having a length of 75 (cm) is used as an example. The blade 11 is made of wood, and the surface of the blade 11 is coated with urethane. One end of the blade 11 is fixed using a fixing member 12, and the blade 11 is a so-called cantilever. The displacement of the tip portion of the blade 11 can be measured using the accelerometer 15. The signal output from the accelerometer 15 is amplified by the amplifier 16 and then output to the computer 17. As shown in FIG. 3, the x direction is the thickness direction of the blade 11, the y direction is a direction orthogonal to the longitudinal direction of the blade 11, and the z direction is the longitudinal direction of the blade 11.

In the mode test, each excitation position 13 (P ₊₁ , P ₊₂ ,..., P ₋₁ , P ₋₂ ,...) Is struck with a hammer to vibrate the blade 11, and then the frequency response function (FRF : Frequency Response Function), and then the mode shape is identified based on the frequency response function (FRF).

  FIG. 4 is a diagram showing the vibration of the mode test apparatus shown in FIG. 3, and shows the vibration response with respect to the frequency. As shown in FIG. 4, the natural frequency of the first-order mode is 36 Hz, the natural frequency of the second-order mode is 123 Hz, the natural frequency of the third-order mode is 262 Hz, and the natural frequency of the fourth-order mode. Is 300 Hz. Here, the first and second modes are out-of-plane bending vibrations, and the third and fourth modes are torsional vibrations. In the following, only the primary mode and the secondary mode having a large vibration response, that is, out-of-plane bending vibration will be considered.

ここで、Ｃ_１〜Ｃ_４、λ_ｒは係数であり、境界条件を考慮した最小二乗法を用いることで決定することができる。 The vibration in the primary mode and the vibration in the secondary mode can be expressed using an interpolation function using a trigonometric function shown below. However, this is only an example, and appropriate expression change is possible depending on the specifications of the target blade.

Here, C _{1 to} C ₄ and λ _r are coefficients, and can be determined by using a least square method in consideration of boundary conditions.

  FIG. 5 is a diagram illustrating the relationship between the measurement value of the primary mode and the interpolation function. FIG. 6 is a diagram showing the relationship between the measurement value of the secondary mode and the interpolation function. As shown in FIGS. 5 and 6, the measured value almost coincides with the interpolation function, and the vibration in each mode can be expressed using the interpolation function shown in Equation 6.

  FIG. 7 is a diagram illustrating a case where the first-order mode interpolation function illustrated in FIG. 5 is second-order differentiated. FIG. 8 is a diagram illustrating a case where the second-order mode interpolation function illustrated in FIG. 6 is second-order differentiated. The second derivative of the interpolation function in each mode indicates the distortion distribution. Therefore, by providing a strain gauge at a location where the absolute value of strain is maximized, the sensitivity of the strain gauge can be improved.

  In the examples shown in FIGS. 7 and 8, the absolute value of the second derivative of the interpolation function of each mode is maximized in the vicinity of z = 0.55 (m). Therefore, by providing a strain gauge in the vicinity of z = 0.55 (m), the sensitivity of the strain gauge can be improved. In FIG. 8, the absolute value of the second-order derivative of the interpolation function of the second-order mode is zero in the vicinity of z = 0.26 (m). On the other hand, in FIG. 7, the absolute value of the second derivative of the interpolation function of the first-order mode is not zero in the vicinity of z = 0.26 (m). Therefore, by providing a strain gauge in the vicinity of z = 0.26 (m), the strain caused by the primary mode and the strain caused by the secondary mode can be well separated. Here, the place where the absolute value of the second-order differential of the interpolation function is zero corresponds to the vibration node.

  Further, the deflection of the blade can be dynamically identified by calibrating the strain gauge value (voltage value) from the strain distribution values shown in FIGS.

  In a wind power generator, a blade may vibrate due to strong wind or pulsation of wind. In particular, when the blade resonates, the vibration of the blade increases, which causes a problem that the blade fatigues and breaks, or the blade contacts the tower. Therefore, a wind turbine generator capable of accurately monitoring blade vibration in real time has been required.

  Therefore, in the wind turbine generator 1 according to the present embodiment, at least two strain gauges are arranged in series in the longitudinal direction of the blade, and the vibration component of the primary mode of the blade is determined using signals output from these strain gauges. The vibration component of the secondary mode is calculated. As described above, in the wind turbine generator 1 according to the present embodiment, the vibration component of the primary mode and the vibration component of the secondary mode are calculated using the strain gauge signal. Can be monitored. Accordingly, since the deflection of the entire blade can be monitored instead of the distortion at a specific location of the blade, the vibration of the blade can be monitored more accurately than in the past.

  Further, in the wind turbine generator 1 according to the present embodiment, by monitoring the natural frequency of the primary mode and the natural frequency of the secondary mode, abnormalities of the blade (for example, cracks in the blade or deposits on the blade). Can be detected). In other words, blade abnormality can be detected by detecting changes in the natural frequency of the primary mode and changes in the natural frequency of the secondary mode.

  In the wind power generator 1 according to the present embodiment, the vibration state of the blade may be adjusted based on the calculated vibration information. FIG. 9 is a block diagram illustrating a control system included in the wind turbine generator according to the present embodiment. As shown in FIG. 9, the control system included in the wind turbine generator according to the present embodiment includes a strain gauge 21 (corresponding to the strain gauges 3_1 to 3_3 and 4_1 to 4_3 in FIGS. 1 and 2), and a vibration calculation unit 22. , A vibration state adjustment unit 23, a pitch angle adjustment unit 24, a rotation mechanism 25 (corresponding to the rotation mechanism of FIGS. 1 and 2), and a generator 26.

  The strain gauge 21 measures the strain at two locations of the blade and outputs information on the measured strain to the vibration calculation unit 22. The vibration calculation unit 22 calculates the primary mode vibration and the secondary mode vibration of the blade using the signals output from the two strain gauges 21. At this time, the vibration calculation unit 22 converts the strain measured by the two strain gauges into a deflection using a predetermined inverse transformation matrix (see Equation 5), so that the vibration component of the primary mode of the blade and 2 The vibration component of the next mode can be calculated.

  The vibration state adjustment unit 23 adjusts the vibration state of the blade based on the vibration information calculated by the vibration calculation unit 22. For example, the vibration state adjusting unit 23 can attenuate the vibration of the blade by controlling the rotation of the generator 26. In this case, the vibration state adjusting unit 23 may control the rotational speed of the generator 26 by changing the electrical output of the generator 26, or may mechanically brake the rotation of the generator 26. Good. As a result, the rotation speed of the rotation mechanism 25 including the blade can be reduced, and blade vibration can be attenuated.

  Further, the vibration state adjusting unit 23 may attenuate the vibration of the blades by adjusting the pitch angles of the plurality of blades 2_1 to 2_3. Here, the pitch angle is an angle formed by the rotation surface (a surface having the rotation axis 8 as a normal line) and the blade. The vibration state adjustment unit 23 uses the pitch angle adjustment unit 24 to adjust the pitch angle of the plurality of blades 2_1 to 2_3 (for example, increase the pitch angle), thereby reducing the rotation speed of the rotation mechanism 25 including the blades. And the vibration of the blade can be damped.

  For example, the vibration state adjusting unit 23 may attenuate the vibrations of the blades 2_1 to 2_3 when the displacement at the tip portions of the blades 2_1 to 2_3 is equal to or greater than a predetermined first threshold value. Here, the first threshold is a distance at which the blades 2_1 to 2_3 and the tower 7 may come into contact with each other when the tip portions of the blades 2_1 to 2_3 are displaced further. Thereby, contact with the tip of blades 2_1 to 2_3 and tower 7 can be avoided.

  In addition, the vibration state adjusting unit 23 may attenuate the vibration of the blades 2_1 to 2_3 when the displacement of the blades 2_1 to 2_3 at a predetermined position becomes equal to or greater than a predetermined second threshold value. Here, the second threshold value corresponds to a displacement amount that, when the predetermined positions of the blades 2_1 to 2_3 are displaced more than this, leads to shortening of the life due to breakage or fatigue of the blades. Thereby, shortening of the life due to breakage or fatigue of the blades 2_1 to 2_3 can be avoided.

  In addition, the vibration state adjusting unit 23 may attenuate the vibrations of the blades 2_1 to 2_3 when the vibration displacement in the secondary mode of the blades 2_1 to 2_3 is equal to or greater than a predetermined third threshold value. Here, the third threshold value corresponds to a displacement amount that, if the predetermined position of the blades 2_1 to 2_3 is further displaced, leads to shortening of the life due to breakage or fatigue of the blade. Thus, by paying attention to the vibrations of the secondary modes of the blades 2_1 to 2_3, it is possible to detect excessive vibrations of the blades and avoid shortening the life due to breakage or fatigue of the blades 2_1 to 2_3. it can.

  In the wind power generator 1 according to the present embodiment, for example, a strain sensor may be provided in each of the blades 2_1 to 2_3, and the pitch angle may be adjusted only for blades that are excessively vibrating. That is, the pitch angles of the blades 2_1 to 2_3 may be adjusted independently. The blades 2_1 to 2_3 may have slightly different natural frequencies due to manufacturing errors or the like. Therefore, it is preferable to provide a strain sensor on each of the blades 2_1 to 2_3 and monitor the vibration of each of the blades 2_1 to 2_3 independently.

  Next, operation | movement of the wind power generator concerning this Embodiment is demonstrated. FIG. 10 is a flowchart for explaining the operation of the wind turbine generator according to the present embodiment. In the wind turbine generator according to the present embodiment, first, when the wind turbine generator is operating, that is, the rotating mechanism 25 (the blades 2_1 to 2_3 and the hub 5) rotates and the generator 26 generates power. At this time, the strain of the blade is measured using the strain gauge 21 provided on the blade (step S1).

  The strain gauge 21 outputs information on the measured strain to the vibration calculation unit 22. The vibration calculation unit 22 converts the strain measured by the strain gauge 21 into deflection using a predetermined conversion matrix, and calculates the vibration component of the primary mode and the vibration component of the secondary mode of the blade (step S2). ).

  Then, the vibration state adjustment unit 23 determines whether or not the amount of displacement of the blade at a predetermined position is equal to or greater than a predetermined threshold (step S3). If the amount of displacement of the blade at the predetermined position is smaller than the predetermined threshold (step S3: No), the operations after step S1 are repeated. On the other hand, when the displacement amount at the predetermined position of the blade is equal to or greater than the predetermined threshold (step S3: Yes), the vibration state adjusting unit 23 adjusts the vibration state of the blade (step S4).

  For example, the vibration state adjusting unit 23 can attenuate blade vibrations by controlling the rotation of the generator 26 or adjusting the pitch angles of the plurality of blades 2_1 to 2_3. At this time, the vibration state adjusting unit 23 may attenuate the vibration of the blade when the distance between the tip of the blade and the tower is equal to or less than a predetermined first threshold value. Further, the vibration state adjusting unit 23 may attenuate the vibration of the blade when the displacement of the blade at a predetermined position becomes equal to or greater than a predetermined second threshold value. Further, the vibration state adjusting unit 23 may attenuate the vibration of the blade when the displacement of the vibration in the secondary mode of the blade is equal to or greater than a predetermined third threshold value. After the adjustment of the vibration state of the blade is completed, the operation from step S1 is repeated again.

  As described above, in the wind turbine generator according to the present embodiment, the vibration component of the first-order mode and the vibration component of the second-order mode of the blade are calculated using the signal output from the strain gauge. The blade vibration state is adjusted based on the vibration information. Therefore, since the vibration of the blade can be suppressed when the blade vibrates excessively due to resonance or the like, the life of the wind turbine generator can be extended.

<Embodiment 2>
Next, a second embodiment of the present invention will be described. The wind power generator according to the present embodiment differs from the wind power generator according to the first embodiment in that a noise sensor is provided at a position separated from the wind power generator. Since it is the same as that of the wind power generator concerning Embodiment 1 except this, the same code | symbol is attached | subjected to the same component and the overlapping description is abbreviate | omitted.

  FIG. 11 is a block diagram illustrating a control system provided in the wind turbine generator according to the present embodiment. As shown in FIG. 11, the control system included in the wind turbine generator according to the present embodiment includes a strain gauge 21 (corresponding to the strain gauges 3_1 to 3_3 and 4_1 to 4_3 in FIGS. 1 and 2), and a vibration calculation unit 22. , A vibration state adjustment unit 23, a pitch angle adjustment unit 24, a rotation mechanism 25 (corresponding to the rotation mechanism in FIGS. 1 and 2), a generator 26, and a noise sensor 27.

  The noise sensor 27 is provided at a position separated from the wind turbine generator, and can measure noise generated by the wind turbine generator. As the noise sensor 27, for example, a microphone or a pressure sensor can be used. The noise of the wind power generator is considered to be caused by, for example, wind noise generated by the blade or low-frequency vibration of the blade.

  In the wind turbine generator according to the present embodiment, the vibration state adjustment unit 23 determines the blade vibration state based on the vibration information calculated by the vibration calculation unit 22 and the noise level measured by the noise sensor 27. It is adjusted. That is, the vibration state adjustment unit 23 can adjust the vibration state of the blade in consideration of both the displacement of the blade at a predetermined position and the noise level measured by the noise sensor 27. For example, even if the displacement of the blade at a predetermined position is equal to or less than a predetermined threshold value, the vibration state adjusting unit 23 determines that the vibration of the blade is greater than a certain reference value. Adjust the vibration state of the blade so that is attenuated.

  In the wind turbine generator according to the present embodiment, at least one of a signal transmitted from the strain gauge to the vibration calculating unit 22 and a signal transmitted from the noise sensor 27 to the vibration state adjusting unit 23 is wirelessly used. You may make it transmit. In this manner, by using wireless technology, a sensor network can be easily constructed even for a large-scale wind power generator.

  Next, examples of the present invention will be described. FIG. 12 is a front view showing the wind turbine generator 31 used in the experiment. In this embodiment, a wind power generator in which three blades are arranged radially from the hub 35 at intervals of 120 degrees is used. Two strain sensors 33 and 34 are provided on one blade 32 of the plurality of blades. The signals from the strain sensors 33 and 34 were collected by the sensor network 41 and then wirelessly transferred to the computer 44 via the wireless module 42. The displacement of the blade 32 was obtained by processing the distortion information with the computer 44. The rotational speed and position of the blade 32 were measured using a magnetic sensor 43. The signal from the magnetic sensor 43 was also wirelessly transferred to the computer 44 via the wireless module 42.

  The power generation capacity of the wind power generator 31 used in this example was 300 W. As the blade 32, the blade described with reference to FIG. At this time, the length in the longitudinal direction of the blade extending radially from the hub 35 was 68.5 (cm). Further, in this embodiment, in order to examine the influence of the tower 37 on the vibration of the blade, the vibration of the blade in the case where the plate 39 is installed in front of the tower 37 and in the case where it is not installed is examined. Further, as shown in FIG. 13, out of the deflection of the blade 32, the deflection toward the tower 37 side is defined as plus deflection, and the deflection away from the tower 37 is defined as minus deflection.

  FIG. 14 is a diagram showing the change over time of the displacement of the tip of the blade 32 (when there is no plate in front of the tower). FIG. 15 is a diagram showing the change over time of the displacement of the tip of the blade 32 (when there is a plate in front of the tower). As shown in FIGS. 14 and 15, the rotation frequency of the rotation mechanism (blade 32) was 4.9 Hz. 14 and 15, the portion where the signal of the magnetic sensor is at a high level indicates a region where the tower 37 and the blade 32 overlap.

  As shown in the measurement result of FIG. 14, when there is no plate in front of the tower 37, deflection in the direction opposite to the wind direction (that is, minus deflection) occurs in front of the tower 37. In addition, when the plate is in front of the tower 37, the blade 32 is deflected more than when the plate is not in front of the tower 37. Thus, by using the wind power generator according to the present invention, it was possible to monitor blade vibration in real time and accurately.

  The present invention has been described with reference to the above-described embodiment and examples. However, the present invention is not limited only to the configurations of the above-described embodiment and examples. It goes without saying that various modifications, corrections, and combinations that can be made by those skilled in the art within the scope of the invention are included.

DESCRIPTION OF SYMBOLS 1 Wind generator 2_1-2_3 Blade 3_1-3_3, 4_1-4_3 Strain gauge 5 Hub 6 Nacelle 7 Tower 8 Rotating shaft 11 Blade 12 Fixing member 13 Excitation position 15 Acceleration sensor 16 Amplifier 17 Computer 21 Strain gauge 22 Vibration calculation part 23 Vibration State adjusting unit 24 Pitch angle adjusting unit 25 Rotating mechanism 26 Generator 27 Noise sensor 31 Wind power generator 32 Blade 33, 34 Strain sensor 35 Hub 37 Tower 41 Sensor network 42 Wireless module 43 Magnetic sensor 44 Computer

Claims (15)

A rotation mechanism comprising a hub and a plurality of blades arranged radially around the rotation axis of the hub;
A nacelle comprising a generator driven by the rotating mechanism;
A tower that supports the nacelle;
First and second strain gauges provided on at least one of the plurality of blades and arranged in series in a longitudinal direction of the blade;
A vibration calculation unit that calculates a vibration component of a primary mode and a vibration component of a secondary mode of the blade using signals output from the first and second strain gauges;
Wind power generator.   2. The wind turbine generator according to claim 1, wherein the vibration calculation unit converts the strain measured by the first and second strain gauges into a deflection using a predetermined inverse transformation matrix. The wind power generator according to claim 2, wherein the vibration calculation unit converts the strain measured by the first and second strain gauges into a deflection using the following equation.

Here, z _d is an arbitrary position of the blade, t is time, ν is displacement, V ₁ (z _d ) is a mode-shaped value (primary mode) in z _d expressed by an interpolation function, and V ₂ (z _d ) is the value of the mode shape (second order mode) in z _d expressed by the interpolation function, ε ₁ is the strain measured with the first strain gauge, ε ₂ is the strain measured with the second strain gauge, r ₁ is the distance from the central axis of the blade at z ₁ to the surface to which the first strain gauge is attached, and r ₂ is from the central axis of the blade at z ₂ to the surface to which the second strain gauge is attached. Distance. The wind power generator according to claim 3, wherein the interpolation function is a function shown below.

  5. The wind turbine generator according to claim 3, wherein at least one of the first and second strain gauges is disposed at a position where the absolute value of the second derivative of the interpolation function is the largest.   6. The wind power according to claim 3, wherein one of the first and second strain gauges is disposed at a position where an absolute value of a second-order derivative of the interpolation function is zero. Power generation device. Detecting an abnormality of the blade using at least one of a change in the natural frequency of the primary mode and a change in the natural frequency of the secondary mode calculated by the vibration calculation unit;
The wind power generator according to any one of claims 1 to 6.   The wind turbine generator according to any one of claims 1 to 7, further comprising a vibration state adjustment unit that adjusts a vibration state of the blade based on vibration information calculated by the vibration calculation unit.   The wind power generator according to claim 8, wherein the vibration state adjusting unit attenuates vibration of the blade by controlling rotation of the generator. The rotating mechanism includes a pitch angle adjusting unit capable of adjusting a pitch angle of the blade,
The wind power generator according to claim 8 or 9, wherein the vibration state adjustment unit attenuates vibration of the blade by adjusting a pitch angle of the blade.   The wind turbine generator according to any one of claims 8 to 10, wherein the vibration state adjusting unit attenuates vibration of the blade when a displacement at a tip portion of the blade becomes a first threshold value or more.   The wind power according to any one of claims 8 to 10, wherein the vibration state adjustment unit attenuates the vibration of the blade when the displacement of the blade at a predetermined position becomes equal to or greater than a predetermined second threshold value. Power generation device.   11. The vibration state adjustment unit according to claim 8, wherein the vibration of the blade is attenuated when a vibration displacement in the secondary mode of the blade becomes a predetermined third threshold value or more. The wind power generator described. A noise sensor provided at a position separated from the wind turbine generator, and measuring noise generated by the wind turbine generator;
The vibration state adjustment unit adjusts the vibration state of the blade based on the vibration information calculated by the vibration calculation unit and the noise level measured by the noise sensor.
The wind power generator according to any one of claims 8 to 13.   15. At least one of a signal transmitted from the first and second strain gauges to the vibration calculation unit and a signal transmitted from the noise sensor to the vibration state adjustment unit are transmitted using radio. The wind power generator described.

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