JP2011027050A - Wind turbine generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a cost for the control of a wind turbine generator. <P>SOLUTION: The wind turbine generator 10 includes a wind turbine 12, a generator 24 coupled to a rotating shaft 14 of the wind turbine 12, a supporting means 34 for supporting the generator 24 and the wind turbine 12, and a control means 62 which is disposed at a position apart from the wind turbine 12 and the generator 24 with the supporting means 34 interposed therebetween and which controls the operation of the wind turbine 12 and/or the generator 24. The wind turbine generator further includes a strain sensor which comprises an optical fiber 48 in which fiber gratings (FBG) 42, 44, 46 are formed, a light source 50 for emitting light L thereto, and a wavelength detector 56 for detecting the wavelengths of the light reflected on the FBGs 42, 44, 46 and which detects the vibration of the generator. Light signals Lc, Lp are used as control signals which are emitted from the control means 62 and control the operation of the wind turbine 12 and/or the generator 24. A signal transmission passage for transmitting the light signals Lc, Lp is configured using at least a part of the optical fiber 48. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wind power generator that drives a generator by wind power.

  2. Description of the Related Art Conventionally, as shown in, for example, Patent Document 1, a wind turbine generator that receives wind power with a windmill (propeller) and drives the generator with the rotational force to obtain electric power is known. Recently, as this type of wind turbine generator, a small device with a rated output of 1 kW or less, which has a small windmill and can constantly generate power even in a place where strong winds are difficult to blow, has attracted attention. Development is also actively done.

  By the way, this wind power generator may be subjected to extremely strong winds or earthquake vibrations, and the generator may cause abnormal vibrations due to, for example, uneven wear of bearings. In such a case, it is desirable to stop the operation or prevent vibrations such as reducing the rotational speed of the windmill in order to prevent destruction. Therefore, conventionally, as shown in Patent Document 2, a strain sensor that detects vibrations in the vicinity of the windmill is provided, and when the strain sensor detects large vibrations, the above-described vibration-proofing measures are performed. Wind generators have also been proposed.

  In such a wind power generation apparatus, it is generally necessary to detect vibrations of a plurality of parts of the wind power generation apparatus, that is, for example, the vicinity of the generator and the column part. In that case, if a strain sensor made of a piezo element or the like is used, individual electrical wiring is required for each sensor, so that the larger the number of sensors installed, the more cost is required. Under such circumstances, in Patent Document 3, a strain sensor made of an optical fiber provided with a fiber grating (hereinafter referred to as FBG) is applied to detect vibration in a plurality of portions of the wind power generator. Has been proposed.

  Hereinafter, this strain sensor will be described. The FBG is an optical fiber in which a diffraction grating continuous in the length direction is formed in a core portion. Each grating portion of the diffraction grating is formed, for example, by irradiating the core portion with ultraviolet rays to change the refractive index of only that portion, or by providing a slit in the core portion. When light having a certain wavelength band is input from one end of an optical fiber having such an FBG, light of a specific wavelength corresponding to the period is diffracted in the FBG portion, but the FBG is distorted by stress. As the period changes, the wavelength of the diffracted light changes. Therefore, by detecting the wavelength variation of the light diffracted by the FBG and reflected to the one end side of the optical fiber, it is possible to detect the vibration received by the FBG.

  The strain sensor made of an optical fiber provided with this FBG can detect vibrations for each part of the FBG by providing a plurality of FBGs having different periods, so that it is possible to reduce the cost of many parts of the wind turbine generator. Vibration can be detected. Unlike the large wind power generator, the small wind power generator described above has a structure that can flex flexibly without using high rigidity, unlike the large wind power generator. There are many. In the wind power generator having such a structure, the vibration sensor of the FBG is particularly suitable because vibrations of a plurality of portions in the support column may be detected.

  In the wind power generator, in addition to measures against strong winds and the like, vibration in the vicinity of the generator may be detected in order to detect an abnormality in the generator. However, the strain sensor composed of the FBG detects such vibration. Of course, it can also be used.

  On the other hand, in the wind turbine generator as described above, in order to control the operation of the generator, and further to monitor the operation status of the generator, a generator part and control means installed on the ground are provided. A control wiring to be connected is required. Conventionally, this type of control wiring has been applied with electric wiring using general copper wire.

JP 2002-155850 A JP 2007-205225 A JP 2007-114072 A

  As the amount of information of the wind power generator increases, the control wiring described above is required to have a higher speed range, which causes a significant increase in the installation cost of the wind power generator. In addition, when a control wiring using a copper wire is used, an electric signal for control to transmit the control wiring is easily affected by noise generated from a generator or noise coming from the outside.

  The present invention has been made in view of the above circumstances, and it is possible to keep the cost of a part related to control low even if the amount of information increases, and to prevent the influence of noise on the control signal. An object is to provide a power generator.

The wind power generator according to the present invention uses the optical fiber as a signal transmission path for transmitting a control signal in the wind power generator using a strain sensor made of an optical fiber equipped with an FBG as described above. In terms of
In a wind turbine generator comprising a windmill, a generator connected to the rotating shaft of the windmill, and a control means for controlling the operation of the windmill and / or the generator,
An optical fiber in which an FBG is formed, a light source that makes light incident on the optical fiber, and a wavelength detector that detects the wavelength of the light reflected by the FBG, and a strain sensor that detects at least some vibrations of the power generation device are provided. ,
An optical signal is used as a control signal emitted from the control means to control the operation of the windmill and / or generator,
The signal transmission path for transmitting the optical signal is configured by using at least a part of the optical fiber.

In the wind power generator of the present invention,
Prop that supports the windmill and generator is provided,
The control means is disposed at a position away from the windmill and the generator with the strut in between,
It is desirable that the optical fiber is disposed along the support column.

  On the other hand, it is desirable that the optical signal has a wavelength different from that of the light emitted from the light source constituting the strain sensor.

  The wind power generator of the present invention is preferably configured such that the optical signal and the light emitted from the light source constituting the strain sensor are propagated through the optical fiber in a time-division manner.

  In the wind turbine generator according to the present invention, the optical fiber has a plurality of FBGs having different periods, and the light source emits light including wavelength components that can be diffracted by the plurality of FBGs. It is desirable.

  Further, in the wind turbine generator of the present invention, the frequency component synchronized with the frequency detected by the frequency detector from the frequency detector that detects the frequency of the output of the generator and the wavelength detection signal output from the wavelength detector ( That is, it is desirable to provide means for removing the same frequency component and its harmonic component.

  According to the wind power generator of the present invention, an optical signal is used as a control signal that is emitted from the control means and controls the operation of the windmill and / or generator, and the signal transmission path that transmits this optical signal constitutes the strain sensor. Since the optical fiber is configured using at least a part of the optical fiber, the cost of the part related to the control can be kept low even if the amount of information increases. In other words, when an optical signal is transmitted through an optical fiber, it is generally possible to transmit at a higher speed than when an electrical signal is transmitted. It can be transmitted by optical fiber. In addition, since this optical fiber originally serves as a strain sensor, a transmission path dedicated to the control signal is not required, and the configuration for signal transmission is greatly simplified. It becomes possible to keep the cost of the part concerned low.

  As described above, the cost reduction effect by omitting the transmission line dedicated to the control signal is provided in the wind power generator of the present invention, as described above, provided with the support for supporting the wind turbine and the generator, and the control means is configured to support the support. It is particularly noticeable if the optical fiber is placed along the struts and is positioned at a distance from the windmill and generator. That is, in the case of providing a control signal dedicated transmission line in a wind turbine generator having a support as described above, the dedicated transmission line extends along the support and becomes costly. As a result, a greater cost reduction effect can be obtained.

  In addition, since noise generated from the generator or noise coming from the outside is generally electrical, the control signal, which is an optical signal propagating through the optical fiber, is less susceptible to this type of noise.

  Furthermore, when an electrical signal is used as a control signal, it is necessary to configure the signal transmission path so as not to cause problems due to a strong electric field or humidity. Since no problem occurs, the wind power generator of the present invention is highly reliable in that respect.

  In the wind power generator of the present invention, when the above optical signal has a wavelength different from that of the light emitted from the light source constituting the strain sensor, the two types of light are distinguished by the wavelength. The vibration element analysis by the strain sensor can be made easier.

  Further, when the wind power generator of the present invention is configured such that the optical signal and the light emitted from the light source constituting the strain sensor are time-divided with each other and propagate through the optical fiber, these two types of light Is discriminated on the time axis, the vibration element analysis by the strain sensor can be performed more easily in this case as well.

  On the other hand, in the wind turbine generator according to the present invention, in particular, the optical fiber has a plurality of FBGs having different periods, and the light source emits light including wavelength components that can be diffracted by the plurality of FBGs. In this case, light having different wavelengths is diffracted in each of the plurality of FBGs. Therefore, if the optical fiber is disposed so that each of the plurality of FBGs is located in a different part of the generator, vibrations in the plurality of parts of the generator can be detected.

  In the wind power generator of the present invention, in particular, the frequency detection means for detecting the frequency of the output of the generator and the frequency detection signal output from the wavelength detector constituting the strain sensor, the frequency detected by the frequency detection means is used. When a means for removing synchronized frequency components is provided, only vibrations caused by external factors such as strong winds can be accurately detected, excluding vibration components due to normal rotation of the generator.

  Hereinafter, this point will be described in detail. In general, a generator has a rotor and / or a stator having a plurality of poles, so that the generator output varies periodically with the rotation of the rotor. That is, unless a commutator or the like is particularly provided, the output of the generator is an alternating current. On the other hand, since the plurality of poles are present, the generator may periodically vibrate as the rotor rotates. Since this vibration has the same frequency as the frequency of the generator output or a harmonic thereof, if the frequency component synchronized with the generator output is removed from the wavelength detection signal output by the wavelength detector, power generation Vibration detection signals can be obtained that show only vibrations that need to take anti-vibration measures, such as vibrations caused by external factors such as strong winds that are not related to normal machine vibrations, and abnormalities in generators due to uneven wear of bearings, etc. It becomes like this.

The schematic block diagram which shows the wind power generator by one Embodiment of this invention. The graph which shows the reflection diffraction characteristic of the fiber grating in the wind power generator of FIG.

10 Wind power generator
12 windmill
16 Electromagnetic clutch
18 gear box
24 generator
28 Nacelle control unit
30 photodetectors
32 casing
34 Prop
39 Transmission line
42, 44, 46 Fiber grating
48 optical fiber
50 Laser light source
52 turnout
54 Condensing lens
56 Wavelength detector
58 Signal processing circuit
60 multiplexer
62 Control circuit

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partially broken side view showing a schematic configuration of a wind turbine generator according to an embodiment of the present invention. As shown in the figure, this wind power generator 10 includes a windmill (propeller) 12 that rotates by receiving wind power, an electromagnetic clutch 16 that is connected to a rotating shaft 14 of the windmill 12, and a speed increaser that is connected to the electromagnetic clutch 16. 18, a generator 24 having a rotor 22 connected to the output shaft 20 of the speed increaser 18, a flywheel 26 connected to the rotor 22, and a nacelle for controlling the operation of the electromagnetic clutch 16. An internal control unit 28 and a photodetector 30 for inputting a light detection signal to the internal control unit 28 in the nacelle are provided. The above elements 12 to 30 are disposed in a casing 32, and the casing 32 is fixed on a support column 34.

  The support column 34 is fixed on a leg portion 36, and a control box 38 having elements to be described later is placed on the leg portion 36. A cylindrical rotating part 40 is formed at the bottom of the casing 32 constituting the nacelle part, and the rotating part 40 is rotatably held at the upper end part of the leg part 36.

  In the wind turbine generator 10 configured as described above, when the wind turbine 12 receives wind, the rotating shaft 14 rotates, and the rotation is increased by the speed increaser 18 and then transmitted to the rotor 22 of the generator 24. In this way, power is generated by rotating the rotor 22 of the generator 24. The power generation output P of the generator 24 is transmitted via a power transmission line 39 disposed in the support column 34 and the control box 38, and subjected to processing such as rectification by means not shown, and then stored in, for example, a capacitor. Alternatively, it is directly used for driving electrical equipment.

  Note that the wind turbine generator 10 of the present embodiment is formed to be relatively small and can generate power even with a slight wind. That is, the diameter of the windmill 12 is about 3 m as an example, the generator 24 can generate power from, for example, a wind speed of about 5 m / s (seconds), and the rated output is about 1 kW as an example.

  In this type of wind power generation apparatus 10, it is necessary to detect abnormal vibrations of the main part of the apparatus due to an increase in wind speed, an abnormality in the structure, or the like for safe operation and prevention of destruction. Hereinafter, a configuration for that purpose will be described. The strain sensor that detects this vibration basically includes an optical fiber 48 in which, for example, three FBGs (fiber gratings) 42, 44, and 46 are formed in the core, a laser light source 50 that makes the laser light L incident thereon, A branching device 52 that branches a laser beam L and a reflected beam LR, which will be described later, a condensing lens 54 that converges the laser beam L on one end surface 48a of the optical fiber 48 and enters the optical fiber 48 from there, and the reflection A wavelength detector 56 for detecting the wavelength of the light LR and a signal processing circuit 58 for processing a wavelength detection signal output from the wavelength detector 56 are configured. The optical fiber 48 is disposed along with the power transmission line 39 so as to pass through the cylindrical rotating portion 40.

  The laser light L incident on the optical fiber 48 and propagating therethrough is reflected and diffracted by the FBGs 42, 44 and 46. These FBGs 42, 44, and 46 are formed with different periods, so that the center wavelengths (peak wavelengths) of the light that is reflected and diffracted under a stationary state are respectively λ1, λ2 and λ3 are different from each other. Note that the period of the FBGs 42, 44, and 46 means that when the lattice parts that are periodically connected to each other are formed by changing the refractive index of only a part of the core part as described above, for example, the refractive index changes. If the lattice portion is formed by providing a slit in the core portion, it is the interval (pitch) of the slit.

  The laser light source 50 is composed of, for example, three different semiconductor lasers and the like, and emits three types of laser light L having a predetermined width including the wavelengths λ1, λ2, and λ3. Therefore, when the laser light L is incident on the optical fiber 48 and propagates through the core portion, the lights having the central wavelengths λ1, λ2, and λ3 are reflected and diffracted at the FBGs 42, 44, and 46, respectively, and the reflected light LR is one of the optical fibers 48. The light exits from the end face 48a. The reflected light LR passes through a multiplexer 60 described later, is branched from the optical path of the laser light L by a branching device 52, is received by a wavelength detector 56, and its wavelength is detected. The condensing lens 54 described above functions to collect the reflected light LR emitted from the one end surface 48a of the optical fiber 48 in a divergent light state with respect to the reflected light LR.

  Here, when an external force is applied to the portion of the optical fiber 48 where the FBGs 42, 44, 46 are provided and the portion is distorted, the period of the FBGs 42, 44, 46 changes, so the center of reflection diffraction in each FBG 42, 44, 46 The wavelength varies from λ1, λ2, and λ3. Therefore, the wavelength detection signal output from the wavelength detector 56 is sent to the signal processing circuit 58, and the signal processing circuit 58 detects the wavelength modulation states in the vicinity of the wavelengths λ1, λ2, and λ3 of the reflected light LR. The vibration applied to the portions 44 and 46 can be detected. That is, the amplitude of the vibration can be detected from the modulation width of the wavelength of the reflected light LR, and the frequency can be detected from the modulation frequency of the wavelength.

  In order to detect each of the wavelength modulation states near the wavelengths λ1, λ2, and λ3 as described above, for example, three types of band-pass filters each having a passband having a wavelength modulation width assumed near the wavelengths λ1, λ2, and λ3 are used. What is necessary is just to detect a wavelength modulation state about each light which passed reflected light LR and passed those band pass filters.

  As the three different semiconductor lasers constituting the laser light source 50, those having an oscillation wavelength in the 1.3 μm or 1.5 μm band, for example, are preferably used. Each of the FBGs 42, 44, and 46 has a period for reflecting and diffracting the laser beam L in such a wavelength band. Further, instead of the laser light source 50 that emits the three types of laser light L as described above, it is also possible to use a light source that emits light over a wide wavelength range including all the assumed center wavelengths λ1, λ2, and λ3. is there.

  Here, the portion of the optical fiber 48 where the FBG 42 is provided is fixed to a bearing 29 that receives the output shaft 20 of the gearbox 18, that is, the rotating shaft of the generator 24. Therefore, the amplitude and frequency of vibration applied to the bearing 29 can be detected by detecting the wavelength modulation state in the vicinity of the wavelength λ1 of the reflected light LR. Normally, vibrations due to normal rotation of the generator 24 and harmonics thereof are continuously applied to the bearing 29 portion. Therefore, the wavelength detection signal output from the wavelength detector 56 and a part of the generator output P sent by the transmission line 39 are input to the signal processing circuit 58, and the signal processing circuit 58 generates power from the wavelength detection signal. Excluding frequency components synchronized with the frequency of the machine output P (that is, components of the same frequency and its harmonic components), vibrations caused by abnormal rotation of the generator 24 and vibrations caused by strong winds in the vicinity of the generator 24 are detected. can do. The detailed reason is as described above.

  As described above, in the present embodiment, the signal processing circuit 58 and the power transmission line 39 constitute frequency detection means for detecting the frequency of the output of the generator, and the signal processing circuit 58 detects the wavelength detected by the wavelength detector 56. A means for removing a frequency component synchronized with the frequency detected by the frequency detecting means from the signal is also configured.

  On the other hand, the portion of the optical fiber 48 where the FBG 44 is provided and the portion where the FBG 46 is provided are fixed to the intermediate portion of the column 34 and the junction between the column 34 and the leg 36, respectively. Therefore, by detecting the wavelength modulation state in the vicinity of the wavelengths λ2 and λ3 of the reflected light LR, it is possible to detect the amplitude and frequency of vibration caused by strong winds applied to the intermediate portion and the joint portion.

  Here, the operation control of the generator 24 by the control circuit 62 arranged at a position away from the windmill 12 and the generator 24 with the support 34 interposed therebetween will be described. Hereinafter, as an example, a case will be described in which the electromagnetic clutch 16 is connected and disconnected to turn the operation of the generator 24 on and off.

  From the signal processing circuit 58 to the control circuit 62, the signal SV indicating the amplitude and frequency of vibration in the three portions of the wind turbine generator 10 described above is input. When the control circuit 62 receives this signal SV, the control circuit 62 compares each of the three amplitudes and frequencies indicated by the signal SV with a preset threshold value for each of them. For example, even one of the amplitude and frequency exceeds the threshold value. In this case, a clutch disengagement signal Lc that is an optical signal is output.

  This clutch disconnection signal Lc is sent into this optical path via a multiplexer 60 arranged in the optical path of the laser light L, and enters the core from one end face 48a of the optical fiber 48. The clutch disengagement signal Lc propagates through the optical fiber 48, exits from the other end surface 48 b of the optical fiber 48 disposed in the casing 32, is collected by the condenser lens 64, and is detected by the photodetector 30. When the photodetector 30 receives the clutch disengagement signal Lc, it photoelectrically converts it and outputs a photodetection signal Ec comprising an electrical signal. The light detection signal Ec is input to the in-nacelle control unit 28. Upon receipt of the photodetection signal Ec, the in-nacelle control unit 28 sends a control signal to the electromagnetic clutch 16 to instruct the clutch to be disengaged. Set. As a result, the generator 24 is disconnected from the windmill 12 and is set to the OFF state, that is, the operation stop state. By doing so, for example, it is avoided that the generator 24 is operated under a storm or a state where an abnormality has occurred in the apparatus, and the wind power generator 10 is prevented from being destroyed.

  After that, when all three amplitudes and frequencies indicated by the signal SV are equal to or less than the corresponding threshold values, the control circuit 62 outputs a clutch connection signal Lp that is an optical signal. This signal Lp also propagates through the optical fiber 48 in the same manner as described above and is detected by the photodetector 30. When receiving the clutch connection signal Lp, the photodetector 30 photoelectrically converts it and outputs a photodetection signal Ep composed of an electrical signal. The light detection signal Ep is input to the in-nacelle control unit 28. Upon receipt of the photodetection signal Ep, the in-nacelle control unit 28 sends a control signal for instructing clutch connection to the electromagnetic clutch 16 to put the electromagnetic clutch 16 in a connected state. Set. Thereby, the operation of the generator 24 is resumed.

  As described above, in the present embodiment, the optical signals Lc and Lp are used as control signals that are emitted from the control circuit 62 and control the operation of the generator 24, and the signal transmission lines that transmit these optical signals Lc and Lp are: Since the optical fiber 48 that constitutes the strain sensor is also used, a control signal dedicated transmission line is not required, and the configuration for signal transmission is greatly simplified, thereby reducing the cost of the part related to control. It becomes possible to suppress.

  As described above, the cost reduction effect by omitting the transmission line dedicated to the control signal becomes more remarkable especially when the support column 34 is formed longer. That is, in such a case, if a dedicated transmission line for the control signal is provided, the cost of the dedicated transmission line becomes higher. Therefore, by omitting it, the cost of the part related to control can be greatly reduced.

  Further, when the wind power generator 10 is highly functional, in addition to the optical signals Lc and Lp for controlling the operation of the electromagnetic clutch 16 described above, for example, the pitch angle of the windmill 12 is controlled, and further, the generator 22 In order to control the operation more complexly, the amount of information is increased, but in this case as well, according to the present invention, the cost of the part related to control is lower than in the case of using a control signal composed of an electrical signal. Can be suppressed. That is, when an optical signal is transmitted via the optical fiber 48, transmission is generally possible at a higher speed than when an electrical signal is transmitted. Therefore, even if the control signal has a large capacity, it is usually transmitted by a single optical fiber. Can be transmitted.

  In addition, since noise generated from the generator 24 or noise coming from the outside is generally electrical, the optical signals Lc and Lp propagating through the optical fiber 48 are not easily affected by this type of noise.

  Furthermore, when an electric signal is used as a control signal, it is necessary to configure the signal transmission path so as not to cause a problem due to a strong electric field or humidity. However, when the optical signals Lc and Lp are propagated in the optical fiber 48, Since such a problem does not inherently occur, the wind turbine generator 10 of the present embodiment is highly reliable from that point.

  The optical signals Lc and Lp are light having a wavelength deviating from the wavelength of the strain sensor laser light L (as described above, the 1.3 μm and 1.5 μm bands), so that the vibration element analysis can be performed more easily. For example, it is desirable to be composed of light having a wavelength in the visible range. Alternatively, the optical signals 48 may be propagated after time division of the optical signals Lc and Lp and the strain sensor laser light L instead of distinguishing them by wavelength.

  Further, the embodiment of the wind turbine generator having a relatively small size has been described above. However, the present invention is naturally applicable to a relatively large wind turbine generator, and in that case as well, as described above. The effect of this is achieved.

Claims (6)

In a wind turbine generator comprising a windmill, a generator connected to the rotating shaft of the windmill, and a control means for controlling the operation of the windmill and / or the generator,
An optical fiber in which a fiber grating is formed, a light source that makes light incident thereon, and a wavelength sensor that detects a wavelength of light reflected by the fiber grating, and a strain sensor that detects vibration of at least a part of the power generation device. Provided,
An optical signal is used as a control signal emitted from the control means to control the operation of the windmill and / or generator,
A wind power generator characterized in that a signal transmission path for transmitting the optical signal is configured using at least a part of the optical fiber. A support for supporting the windmill and the generator is provided,
The control means is disposed at a position away from the windmill and the generator with the strut in between,
The wind power generator according to claim 1, wherein the optical fiber is disposed along the support column.   The wind power generator according to claim 1 or 2, wherein the optical signal has a wavelength different from that of light emitted from a light source constituting the strain sensor.   4. The optical signal and the light emitted from a light source constituting the strain sensor are configured to be time-divided to propagate through the optical fiber. Wind power generator. The optical fiber has a plurality of fiber gratings with different periods,
5. The wind power generator according to claim 1, wherein the light source emits light including a wavelength component that can be diffracted by each of the plurality of fiber gratings. Frequency detection means for detecting the frequency of the output of the generator;
The wind power according to any one of claims 1 to 5, further comprising: means for removing a frequency component synchronized with the frequency detected by the frequency detection means from the wavelength detection signal output by the wavelength detector. Power generation device.

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