JP2007291976A - Pitch drive device of wind turbine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a wind turbine from being excessively rotated in a pitch drive device for changing the pitch of the blades of the wind turbine. <P>SOLUTION: A motor 16 drives a pinion 10 meshed with a ring gear 8 secured to the blades 6b of a rotor 6. A clutch 14 is installed between the pinion 10 and the motor 16. An over-rotation determiner 22 determines the state of the over-rotation of the rotor 6, and disengages the clutch 14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pitch driving device that changes the pitch of blades in a wind turbine.

  In a rotor of a wind turbine, for example, a horizontal axis type wind turbine, blades extend radially from a hub coupled to a horizontally disposed rotating shaft with respect to the rotating shaft. In a wind power generator, a generator is coupled to a rotating shaft of a rotor via a speed increaser. When a gust blows on this windmill, the number of rotations of the rotor increases and the generator and the gearbox may be damaged. As a solution of this point, there is a technique disclosed in Patent Document 1.

  In the technique of Patent Document 1, each blade is configured so that the pitch angle can be individually changed by the pitch driving device, and when a gust blows, all the blades are moved to the feathering position by the pitch driving device. Be made.

JP 2006-16984 A

  However, in the technique of Patent Document 1, even if the blade is instantaneously driven by the pitch driving device, the blade may not be instantaneously driven due to the influence of inertia or the like. When the blades are driven slowly as described above, the rotor rotates too much to prevent damage to the generator and the speed increaser. Further, if the blade is feathered more than necessary at that time by the pitch drive device, lift force in the reverse rotation direction is generated on the blade, the rotational speed of the rotor is reduced, and the power generation efficiency is reduced. .

  An object of this invention is to provide the pitch drive device which can prevent the overrotation of a windmill.

  A pitch drive device for a windmill according to an aspect of the present invention includes a pinion that meshes with a ring gear fixed to a blade of the windmill, and a rotary drive source that drives the pinion. The wind turbine pitch driving device is provided for each blade. For example, an electric motor can be used as the rotary drive source. A clutch is provided between the pinion and the drive source. This clutch is switched to a selected state between a connected state in which the pinion and the drive source are connected and a disconnected state in which both are disconnected, and is normally in a connected state. An over-rotation determination device is provided. The over-rotation determination unit determines a state where the rotation of the windmill is over-rotation, and transmits a signal, for example. Whether or not the engine is over-rotated is determined based on, for example, the rotational speed of the rotor and the wind speed. The clutch is disengaged in response to a signal from the overspeed determination device. In addition, the rotating shaft of the rotor of this windmill is connected to the generator through the speed increaser.

  In the pitch driving device configured as described above, when the rotational speed of the windmill is over-rotated, the over-rotation determination device generates a signal, the clutch is instantaneously disconnected, and the blade is in a free state. Become. As a result, the blade moves quickly and automatically in the feathering direction by the lift of the wind. As a result, the lift for rotating the rotor can be reduced, the rotor can be prevented from over-rotating, and the generator and the gearbox can be prevented from being damaged.

  A rotation detector for detecting the rotation of the drive source can be provided. This rotation detector may be provided in the drive source and detects the pitch angle of the blade. When the state in which the windmill is over-rotated is avoided, the number of rotations of the windmill is reduced. As a result, the signal disappears and the clutch returns to the connected state. Thereafter, the pitch of the blade is controlled using the rotation detector signal. After the clutch is disengaged, the blade moves to the feathering position side, so that the blade pitch angle based on the rotation detector signal is determined. And the angle of the feathering position do not match. Therefore, the value of the pitch angle of the blade based on the signal of the rotation detector is changed to the angle of the feathering position, and the pitch angle of the blade is controlled using the signal of the rotation detector. In order to detect the angle of the feathering position of the blade, a pitch angle detector can be provided on the blade. By providing the pitch angle detector, the blade can be continuously operated without returning to the origin position (for example, the feathering position) and performing an origin return operation for resetting the pitch angle.

  A wind turbine pitch driving apparatus according to another aspect of the present invention includes a drive source that changes a pitch angle of a blade of a wind turbine. As the drive source, a pinion and a rotary drive source can be used as in the above-described embodiment, or the rotary drive source can be directly coupled to the blade and the blade can be rotated by the rotary drive source. . An over-rotation determination unit determines a state in which the number of rotations of the windmill is over-rotation and transmits a signal. This determination can be made by detecting the wind speed or the rotational speed of the rotor and using the detection result. In response to the signal from the over-rotation determination device, the driving force of the driving source is reduced or eliminated. A control unit to which a signal from the over-rotation determination device is supplied can control the drive source so as to reduce or eliminate the drive force of the drive source. In addition, the windmill is connected to the generator via the gearbox.

  With this configuration, for example, when a wind gust blows and the windmill becomes over-rotated, the driving force of the driving source is reduced or eliminated. Therefore, the blade automatically moves in the feathering direction by wind lift. As a result, the lift force that rotates the windmill is reduced, overwinding of the windmill can be prevented, and damage to the generator and the deceleration can be prevented. In addition, when disconnecting or connecting the clutch provided between the drive source and the blade to prevent damage to the generator or the like, a shock is generated when the blade is connected to the drive source. In this case, since the coupling between the driving source and the blade is always maintained, no shock is generated. In addition, when the rotation source is provided with a rotation detector and the pitch angle detected based on the signal from the rotation detector is controlled to match the pitch angle commanded based on the pitch command signal, Since the coupling between the blade and the blade is always maintained, the rotation detector signal does not deviate from the actual pitch angle. Therefore, it is not necessary to return the blade to the reference position, for example, the feathering position. Furthermore, since the blade is not driven to the feathering side more than necessary, the rotational speed of the windmill is not reduced more than necessary, and the power generation efficiency is not extremely reduced.

  The pitch driving device can also regulate the speed of changing the pitch angle of the blade after avoiding a state in which the rotation speed of the windmill is excessive. For example, after the over-rotation state is avoided, the blade is returned to the original position. At this time, since the change speed of the pitch angle of the blade is regulated, the rapid change of the pitch angle of the blade and the rapid reversal of the blade are suppressed, and the blade can be prevented from being damaged. For example, when the drive source is an electric motor, this restriction can be performed by restricting the current flowing through the electric motor. Alternatively, the initial position used for controlling the position of the blade can be set on the feathering side. This can be done by setting it to the most rotated position.

  Further, in this pitch driving device, the driving source can output a force that restricts the movement of the blade to the flat side when the rotational speed of the windmill is excessively rotated. For example, when the drive source is an electric motor, the movement to the flat side is locked, or the current flowing through the electric motor when moving to the flat side is limited to a predetermined current or less. When a gust of wind blows intermittently, the blade may receive a force that temporarily returns to the flat side between the gust of wind. Even if it receives such force, the drive source outputs a force that regulates the movement to the flat side, so the movement of the blade to the flat side can be regulated, and the pitch angle of the blade even if intermittent gusts blow Can be prevented from swinging. Moreover, the impact which arises in a braid | blade by the gust which blew later can be relieved.

  In this pitch driving device, when the driving force of the driving source is reduced or eliminated, the moving speed of the blade toward the feathering side of the blade can be restricted. If comprised in this way, since it can prevent that a braid | blade is moved to the feathering side suddenly by a gust of wind, damage to a braid | blade can be prevented.

  In this pitch driving apparatus, when the driving force of the driving source is reduced or eliminated, if the moving speed of the blade toward the feathering side is equal to or less than a predetermined value, a force for moving the blade in the feathering direction is provided. The drive source can output. With this configuration, even after the wind velocity has once weakened, the blade continues to move toward the feathering side. Therefore, even if a gust of wind blows again, the impact applied to the rotor can be reduced.

  As described above, according to the present invention, it is possible to prevent over-rotation of the windmill by disengaging the clutch and controlling the output of the drive source.

  The wind turbine pitch driving apparatus according to the first embodiment of the present invention is provided with a wind turbine as shown in FIG. This windmill is a horizontal axis windmill, and has a nacelle 4 disposed substantially horizontally at the upper end of the tower 2. The nacelle 4 is provided so as to be rotatable about the longitudinal axis of the tower 2. A wind turbine rotor 6 is provided at one end of the nacelle 4. The rotor 6 has a hub 6a and a plurality of, for example, three blades 6b extending radially from the hub 6a. The hub 6a has a rotation shaft (not shown) arranged horizontally, and this is connected to a generator (not shown) through a speed increaser (not shown) in the nacelle 4. .

  Each blade 6b is provided so as to be rotatable around an axis along the length direction of the tower 2 indicated by a dotted line in FIG. 2, and is a flat position where the surface of the blade is positioned substantially perpendicular to the wind from the front of the hub 6a. And the feathering position where the blade surface is positioned substantially parallel to the wind from the front of the hub 6a. That is, it is pitch driven.

  Therefore, in this pitch drive device, as shown in FIG. 3, ring gears 8 are provided on the peripheral surfaces of the joint portions of the blades 6b with the hub 6a. A pinion 10 is provided, for example, in the bubb 6a so as to mesh with these ring gears 8 respectively. By rotating these pinions 10 forward or backward, the blade 6b rotates around an axis along the length direction of the tower 2 described above.

  As shown in FIG. 1, the pinion 10 is coupled to a clutch, such as a non-excitation electromagnetic clutch 14, via a speed reducer 12, and the clutch 14 is coupled to a rotary drive source, such as an electric motor 16. The clutch 14 makes the speed reducer 12 and the motor 16 connected or disconnected. When the motor 16 rotates in the connected state, the driving force of the motor 16 is transmitted to the speed reducer 12 via the clutch 14. The pinion 10 rotates and the blade 6b rotates. The clutch 14 is normally in a connected state.

  The electric motor 16 is provided with a rotation detector, for example, an encoder 18, and detects the number of rotations of the electric motor 16, and thus the pitch angle from the reference position of the blade 6b, for example, from the flat position or the feathering position. A pitch angle signal representing the detected pitch angle is supplied to the control unit 20. A pitch position command is supplied to the control unit 20 from the outside, and the control unit 20 controls the electric motor 16 so that the pitch angle of the blade becomes the pitch angle indicated by the pitch position command.

  As described above, the clutch 14 connects the speed reducer 12 and the electric motor 16 in a normal state, and the clutch 14 disconnects the speed reducer 12 and the electric motor 16 when a signal is supplied from the overspeed determination unit 22. . The over-rotation determination unit 22 generates a signal when the rotor 6 is over-rotating, for example, rotating more than the rated rotation. Such over rotation occurs, for example, when a gust of wind occurs. In order for the over-rotation determination unit 22 to generate the above signal, the over-rotation determination unit 22 is supplied with a rotor rotation number detection signal from a rotation number detector (not shown) that detects the rotation number of the rotor 6. When this exceeds a reference signal corresponding to the rated speed, the signal is supplied to the clutch 14.

  As a result, the clutch 14 disconnects the speed reducer 12 and the electric motor 16. As a result, the blade 6b enters a free state, and instantaneously rotates toward the feathering position. As a result, the lift force that rotates the rotor 6 is reduced, and the rotational speed of the rotor 6 becomes less than the rated input. As a result, overrotation of the rotor 6 can be prevented.

  When the rotational speed of the rotor 6 becomes equal to or lower than the rated input, the signal from the overspeed determination unit 22 disappears, and the clutch 14 connects the speed reducer 12 and the electric motor 16 again. Thereafter, the control unit 20 controls the electric motor 16 so that the blade 6b forms a pitch angle corresponding to the pitch command signal supplied to the control unit 20. However, the motor 16 does not follow the rotation of the blade 6b while the blade 6b rotates toward the feathering side while the clutch 14 disconnects the speed reducer 12 and the motor 16. Therefore, since the pitch angle signal from the encoder 18 does not correspond to the actual pitch angle, even if the motor 16 is controlled using this pitch angle signal, the blade 6b is controlled to the pitch angle indicated by the pitch position command. I can't. Therefore, the pitch angle detector 24 is provided on the blade 6b side, for example, on the ring gear 4. The pitch angle detection signal generated by the pitch angle detector 24 represents the actual pitch angle of the blade 6b rotating toward the feathering position. Therefore, this pitch angle detection signal is supplied to the control unit 20, and the pitch angle signal from the encoder 18 is matched with the pitch angle detection signal. The electric motor 16 is controlled based on the matched pitch angle signal. Thereby, even if the clutch 14 is disconnected and then connected again, the pitch angle of the blade 6b can be accurately controlled.

  In the above-described embodiment, the over-rotation determination unit 22 determines whether the over-rotation is based on the number of rotations of the rotor 6, but is not limited to this. It is also possible to determine that the engine is over-rotated when the wind speed signal representing the wind speed is equal to or higher than a reference signal representing the wind speed corresponding to the predetermined over-rotation, and to supply the signal to the clutch 14. Alternatively, the lift measurement signal generated by the lift measuring device that measures the lift generated in the blade 6b is supplied to the over-rotation determination unit 22, and this lift measurement signal is greater than or equal to the reference signal representing the lift corresponding to the over-rotation. In some cases, it may be determined that the engine is over-rotated and a signal is supplied to the clutch 14.

  A pitch driving apparatus according to a second embodiment of the present invention is shown in FIG. Similarly to the first embodiment, this pitch driving device is also connected to the rotor 6 having the hub 6a and the blade 6b, the ring gear 8, the pinion 10 meshing with the rotor 6 and the pinion 10 via the speed reducer 12. And an electric motor 16.

  The pitch of the blades 6b is changed by the rotation of the electric motor 16. This pitch change is performed based on a pitch position command given from the outside. This pitch position command is supplied to a position controller 32 via a selection means, for example, a changeover switch 30, and the direction and angle for rotating the electric motor 16 are determined, and further the speed for rotating in the speed controller 34 is determined. Is determined by the current controller 36 and supplied to the electric motor 16.

  The pitch driving device further includes an overspeed prevention controller 38. The over-rotation prevention controller 38 includes a wind speed signal indicating the wind speed received by the wind turbine measured by a wind speed measuring device (not shown), and the rotation speed of the rotor 6 measured by a rotation detector (not shown). And a rotor phase signal from a phase measuring device (not shown) for measuring the phase of the rotor 6 are input. The pitch angle signal of the blade 6 b from the encoder 18 provided in the electric motor 16 is also supplied to the over-rotation prevention controller 38.

  Based on the wind speed signal or pitch angle signal, the over-rotation prevention controller 38 determines whether or not a gust of wind that causes over-rotation is blowing on the rotor 6. For example, when it is determined by comparing with a reference signal and it is determined that a gust of wind is blowing, a command is sent to the current controller 36 to set the current supplied to the motor 16 to zero or to a value for setting the blade 6b to a free state. The current controller 36 is controlled to limit. As a result, due to the gust of wind, the blade 6b rotates in the direction of the feathering position, the blade 6b loses lift, and overrotation of the rotor 6 is prevented.

  When the gust is settled, the current limit is released and the pitch angle of the blade 6b is changed again according to the position command. Before that, the changeover switch 30 supplies the pitch angle signal from the encoder 18 to the position controller 32. To be switched. As a result, the position controller 32 sets the current pitch angle signal as an initial value. Thereafter, the changeover switch 30 is changed over so that a pitch position command is supplied to the position controller 32. Thereby, the blade 6b is controlled with the position of the blade 6b when the gust is settled as an initial position. Therefore, the blade 6b is not reversed to the original initial position side on the flat side, and damage to the blade 6b can be prevented.

  Further, the force acting on each blade 6 b includes a rotational force due to lift and an inertial force and weight of the blade itself due to rotation of the rotor 6. These forces are not necessarily proportional to the wind speed. Therefore, if the thrust by the electric motor 16 is zero or the blade 6b is in a free state, the blade 6b may rotate to the flat position side by its own weight or inertial force. This is because the center of gravity of the blade 6b may not be at the center of rotation, and depending on the rotor phase at that time, the blade 6b may act on its own weight so as to rotate the blade 6b to the flat side, or as described above. This is because if the rotational speed of the rotor 6 decreases when the center of gravity is not at the center of rotation, the inertial force of the blade 6b may act on the flat side. In any case, it is expected that the force for rotating the blade 6b to the flat side is larger than the lift by wind. In such a case, the reduction in the rotational speed of the rotor 6 is delayed.

  Therefore, the over-rotation prevention controller 38 determines whether the force acting on the blade 6b is the feathering direction side rotation direction or the flat side rotation direction from the rotation number signal and the rotor phase signal of the rotor 6, and if it is on the feathering direction side. For example, as described above, the thrust of the electric motor 16 is made zero or free, and the current controller 36 is controlled so as to lock the rotation of the electric motor 16 if it is in the flat direction side. Such a situation is likely to occur when gusts of wind blow intermittently. Instead of determining the rotational direction of the blade 6b from the speed and rotor phase of the rotor 6, the blade 6b may move in the flat direction when the thrust of the electric motor 16 is zero or free, for example, the encoder 18 The blade 6b may be configured to lock in the flat direction when detected from the pitch angle signal.

  Although the thrust of the electric motor 16 is zero or free, the blade 6b is rotated in the feathering direction by the wind so that the speed when the blade 6b rotates in the feathering direction does not exceed a predetermined value. The over-rotation prevention controller 38 controls the current controller 36 so as to limit the current flowing through the electric motor 16. As a result, the rapid rotation of the blade 6b in the feathering direction can be restricted, and damage to the blade 6b and the like can be prevented.

  Further, when the blade 6b rotates in the feathering direction with the thrust of the electric motor 16 being zero or in a free state, the overspeed prevention control from the current controller 36 is that the moving speed is slower than a predetermined speed. When the over-rotation prevention controller 38 determines from the torque information (representing the torque generated by the electric motor 16) supplied to the machine 38, the over-rotation prevention controller 38 switches the changeover switch 30 so that the over-rotation prevention controller A signal is sent from 38 to the position controller 32 so that the torque is balanced. Thus, the blade 6b is rotated to the feathering side by the electric motor 16, and the operation delay to the feathering side can be minimized. In addition, when the gust blows and the blade 6b moves in the feathering direction, even if the gust blows again in a short time after the wind has weakened, the blade 6b is sufficiently feathered on the first gust. Therefore, the impact on the blade 6b due to the second and subsequent gusts can be reduced. In addition, from the torque information from the current controller 36, it was detected that the speed of the blade 6b in the feathering direction was insufficient. Based on the signal from the encoder 18, the speed of the blade 6b in the feathering direction of the blade 6b was detected. You can also.

  In both of the above-described embodiments, the encoder 18 is provided in the electric motor 16 to detect the pitch angle of the blade 6b. However, the present invention is not limited to this. For example, the rotation of the blade 6b can be directly detected. .

It is a block diagram of the pitch control device of a 1st embodiment of the present invention. It is a side view of the windmill with which the pitch control apparatus of FIG. 1 is implemented. It is a perspective view which shows the structure which changes the pitch of the blade in the windmill of FIG. It is a block diagram of the pitch control apparatus of the 2nd Embodiment of this invention.

Explanation of symbols

6 Blade 6b Blade 8 Ring gear 10 Pinion 22 Over-rotation determination device 22
38 Over-rotation prevention controller (over-rotation judgment device)

Claims (7)

In a wind turbine pitch driving device comprising a pinion that meshes with a ring gear fixed to a blade of a wind turbine, and a rotary drive source that drives the pinion,
A clutch is provided between the pinion and the drive source;
Determining a state in which the rotation of the windmill is over-rotating, and comprising an over-rotation determining device for transmitting a signal;
The wind turbine pitch driving device according to claim 1, wherein the clutch is disengaged in response to a signal from the over-rotation determination device. In the pitch drive device of the windmill according to claim 1,
A rotation detector for detecting rotation of the drive source;
When the state in which the windmill is over-rotated is avoided, the clutch is engaged, and the value of the blade pitch angle based on the signal of the rotation detector is changed to the angle of the feathering position. Pitch drive device. In a wind turbine pitch drive device having a drive source for changing the pitch angle of the wind turbine blade,
Determining a state in which the rotational speed of the windmill is over-rotated, and comprising an over-speed determining device for transmitting a signal;
A wind turbine pitch driving device characterized in that the driving force of the driving source is reduced or eliminated in response to a signal from the over-rotation judging device. In the pitch drive device of the windmill according to claim 3,
A wind turbine pitch driving device that regulates a change speed of a pitch angle of the blade after avoiding a state in which the rotation speed of the wind turbine is excessive. In the pitch drive device of the windmill according to claim 3 or 4,
The wind turbine pitch driving device according to claim 1, wherein when the rotational speed of the wind turbine is excessive, the driving source outputs a force that restricts movement of the blade to the flat side. In the pitch drive device of the windmill according to any one of claims 3 to 5,
A wind turbine pitch driving device, wherein when the driving force of the driving source is reduced or eliminated, the driving source regulates the moving speed of the blade toward the feathering side. In the pitch drive device of the windmill according to any one of claims 3 to 6,
When the driving force of the driving source is reduced or eliminated, the driving source outputs a force for moving the blade in the feathering direction when the moving speed of the blade to the feathering side is a predetermined value or less. A wind turbine pitch drive device.

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