Control device, processing circuit, method, non-transitory computer-readable medium and computer program product for controlling wind power generation device

Abstract

The invention provides a control device, a processing circuit, a method, a non-transitory computer readable medium and a computer program product for controlling a wind power generation device. A control device for controlling a wind power generation device provided with a tower and a nacelle, the control device being provided with: a processing circuit configured to control a motor for rotating the nacelle relative to the tower; and a torque information sensor for detecting information relating to torque acting on a gear mechanism from the nacelle, the gear mechanism connecting the tower and the nacelle in a relatively rotatable manner. The processing circuit drives the motor based on a detection value of the torque information sensor.

Description

Technical Field

[0001] The present disclosure relates to a control device, a processing circuit, a method, and a non-transitory computer-readable medium for controlling a wind power generation device. Background Art

[0002] The wind turbine generator disclosed in Japanese Patent Application Publication No. 2021-93900 includes a tower, a nacelle, a hub, multiple blades, and an anemoscope. The nacelle is connected to the upper end of the tower. The nacelle is rotatable about a yaw axis, which coincides with the central axis of the tower. The nacelle houses a generator. The hub is connected to the generator's input shaft. The hub is rotatable about a roll axis perpendicular to the yaw axis. Multiple blades are connected to the hub. The multiple blades rotate integrally with the hub. The anemoscope is mounted on the nacelle. Summary of the Invention

[0003] Problems to be solved by the invention

[0004] In a wind turbine generator such as that disclosed in Japanese Patent Application Publication No. 2021-93900, the efficiency of power generation increases when the direction of the wind with respect to the blades is roughly consistent with the extension direction of the roll axis. In consideration of this, it is preferable to adjust the rotational position of the nacelle about the yaw axis so that the direction of the wind with respect to the blades is consistent with the extension direction of the roll axis. When adjusting the rotational position of the nacelle in this manner, consideration is given to utilizing the measurement results of the wind vane. However, the wind vane is located in a position downwind relative to the blades. Therefore, the wind reaching the wind vane may become turbulent or change direction when passing through the blades. Therefore, the measurement results of the wind vane may not accurately reflect the actual direction of the wind received by the blades.

[0005] Solutions for solving problems

[0006] In one embodiment, a control device for controlling a wind turbine generator is provided. The wind turbine generator includes a tower and a nacelle, and the control device includes: a processing circuit configured to control a motor for rotating the nacelle relative to the tower; and a torque information sensor configured to detect information related to torque acting from the nacelle on a gear mechanism that rotatably couples the tower and nacelle relative to each other, wherein the processing circuit is configured to drive the motor based on a detection value from the torque information sensor.

[0007] In one embodiment, the processing circuit may also be configured to perform the following processing: obtaining a parameter positively correlated with the torque based on the detection value of the torque information sensor; starting to drive the motor to rotate the cabin relative to the tower when the parameter is above a first threshold value; and stopping driving the motor when the parameter is below a second threshold value which is smaller than the first threshold value.

[0008] In one embodiment, the information related to the torque may be strain of bolts connecting the nacelle and the gear mechanism.

[0009] In one embodiment, the torque information sensor may be the first torque information sensor among a plurality of torque information sensors, the motor may be the first motor among a plurality of motors, the bolt may be the first bolt among a plurality of bolts, and the plurality of motors may be configured such that when the nacelle is connected to the gear mechanism, the plurality of motors are arranged circumferentially with the rotation center axis of the nacelle relative to the tower as the center, and each motor is fixed to the nacelle by each bolt, each torque information sensor may be arranged corresponding to each bolt, and the processing circuit may be configured to obtain the parameter based on a value obtained by statistically processing the detection values ​​of the plurality of torque information sensors.

[0010] In one embodiment, the control device may also be provided with a speed detection sensor, which is used to detect the speed of the wind passing through the nacelle. When the direction along the rotation center axis of the blade connected to the nacelle in a plane perpendicular to the rotation center axis of the nacelle relative to the tower is set as a first direction, the direction of the wind with respect to the blade in the plane is set as a second direction, and the acute angle formed by the first direction and the second direction is set as an offset angle, the processing circuit may also be provided with a memory, which stores corresponding information representing the correspondence between the information related to the torque, the speed of the wind and the offset angle. The processing circuit may also be configured to obtain the offset angle as the parameter based on the detection value of the torque information sensor, the detection value of the speed detection sensor and the corresponding information.

[0011] In one embodiment, the control device may also be provided with a speed detection sensor for detecting the speed of wind passing through the nacelle, and the processing circuit may also be configured to perform the following processing: alternately braking the relative rotation of the nacelle with respect to the tower by driving at least one of an electromagnetic brake and a fluid pressure friction brake, and driving the motor, wherein the electromagnetic brake applies a braking force to the output shaft of the motor and the friction brake applies a braking force to the relative rotation of the nacelle with respect to the tower; and when the detection value of the speed detection sensor is below a predetermined set value, only the electromagnetic brake is driven, and when the detection value of the speed detection sensor is greater than the set value, both the electromagnetic brake and the friction brake are driven.

[0012] In another embodiment, a processing circuit for controlling a wind turbine generator is provided. The wind turbine generator includes a tower and a nacelle, and the processing circuit is configured to: obtain information regarding torque acting from the nacelle on a gear mechanism that rotatably couples the tower and nacelle relative to each other; obtain a parameter positively correlated with the torque based on the information; start driving a motor to rotate the nacelle relative to the tower when the parameter is greater than a first threshold; and stop driving the motor when the parameter is less than a second threshold that is smaller than the first threshold.

[0013] In yet another embodiment, a method for controlling a wind turbine generator is provided. The wind turbine generator includes a tower and a nacelle, the method comprising the following steps: a processing circuit acquires information regarding torque acting from the nacelle on a gear mechanism that rotatably couples the tower and nacelle relative to each other; the processing circuit acquires a parameter positively correlated with the torque based on the information; when the parameter is equal to or greater than a first threshold, the processing circuit starts driving a motor to rotate the nacelle relative to the tower; and when the parameter is equal to or less than a second threshold that is smaller than the first threshold, the processing circuit stops driving the motor.

[0014] In another embodiment, a non-transitory computer-readable medium storing a program for controlling a wind turbine generator is provided. The wind turbine generator includes a tower and a nacelle. When executed by a processing circuit, the program causes the processing circuit to perform the following processing: obtaining information regarding torque acting from the nacelle on a gear mechanism that couples the tower and nacelle for relative rotation; obtaining a parameter positively correlated with the torque based on the information; starting driving a motor to rotate the nacelle relative to the tower when the parameter is greater than or equal to a first threshold; and stopping driving the motor when the parameter is less than or equal to a second threshold that is smaller than the first threshold. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a perspective view showing the appearance of a wind turbine generator.

[0016] Figure 2 It is a top view schematically showing a wind turbine generator.

[0017] Figure 3 It is a cross-sectional view schematically showing a part of a wind turbine generator.

[0018] Figure 4 It is a cross-sectional view schematically showing a part of a wind turbine generator.

[0019] Figure 5 This is a schematic diagram of the control device.

[0020] Figure 6 This is a graph showing the amount of power generated by the generator in relation to the passing wind speed.

[0021] Figure 7 This is a flowchart showing the processing procedure of the braking control.

[0022] Figure 8 This is a flowchart showing the processing procedure of the driving control.

[0023] Figure 9 This is a graph showing an example of the correspondence relationship between load torque and bolt strain.

[0024] Figure 10 This is a graph showing an example of the correspondence between the offset angle, the strain of the bolt, and the passing wind speed. DETAILED DESCRIPTION

[0025] Hereinafter, one embodiment of a control device, a processing circuit, a method, and a non-transitory computer-readable medium for controlling a wind turbine generator will be described with reference to the accompanying drawings.

[0026] <Overall Structure>

[0027] like Figure 1 As shown in FIG. 1 , the wind turbine generator 100 includes a tower 110, a ring gear 210, and a nacelle 160. Figure 2 As shown, the wind turbine generator 100 includes a transmission shaft 130 , a hub 140 , and a plurality of blades 150 .

[0028] like Figure 1 As shown, tower 110 is cylindrical. It extends upward from the ground or offshore. The interior of tower 110 is hollow. Power cables and other components for power transmission are laid within tower 110. Hereinafter, the central axis of tower 110 will be referred to as the yaw axis Y. Yaw axis Y extends upward.

[0029] The ring gear 210 is located above the tower 110. Figure 1 In FIG. 2 , the ring gear 210 is shown in an exaggerated manner. Figure 2 As shown, the ring gear 210 is annular. The central axis of the ring gear 210 is roughly consistent with the yaw axis Y. Figure 3 As shown, a plurality of teeth 212 are disposed on the outer circumference of ring gear 210. Teeth 212 are arranged at equal intervals in the circumferential direction centered on the central axis of ring gear 210. The outer diameter of ring gear 210 is substantially identical to the outer diameter of upper wall 112 of tower 110. Ring gear 210 is fixed to upper wall 112 of tower 110.

[0030] like Figure 1 As shown, the nacelle 160 is located above the tower 110 and the ring gear 210. The nacelle 160 has a rectangular parallelepiped shape. Figure 2 As shown in FIG. 1 , when the wind turbine generator 100 is viewed from above, the outer edge of the nacelle 160 is larger than the outer edge of the tower 110 and the ring gear 210. Furthermore, when viewed from above, the ring gear 210 is located within the range surrounded by the outer edge of the nacelle 160. The nacelle 160 is hollow. The nacelle 160 houses the generator 170 and the like. Figure 2 The arrangement, shape, and size of each component shown in the drawings are given to facilitate understanding of these components and do not necessarily correspond to the actual components.

[0031] like Figure 3As shown, a portion of the lower wall 162 of the nacelle 160 faces the ring gear 210. Furthermore, a portion of the lower wall 162 of the nacelle 160 that is radially inward relative to the ring gear 210, centered about the yaw axis Y, faces the upper wall 112 of the tower 110. Furthermore, a support mechanism 90 is disposed between the lower wall 162 of the nacelle 160 and the upper wall 112 of the tower 110. The support mechanism 90 includes bearings and the like. The lower wall 162 of the nacelle 160 is supported by the support mechanism 90. When supported by the support mechanism 90, the nacelle 160 can rotate relative to the tower 110 and the ring gear 210 about the yaw axis Y as the rotation center axis.

[0032] like Figure 2 As shown, transmission shaft 130 extends from the interior of nacelle 160 to the exterior. The central axis of transmission shaft 130 is orthogonal to yaw axis Y. Hereinafter, the central axis of transmission shaft 130 is referred to as roll axis R. Transmission shaft 130 is rotatable about roll axis R. The portion of transmission shaft 130 located inside nacelle 160 is connected to generator 170 via a speed-increasing gearbox (not shown). Generator 170 converts the rotation transmitted from the speed-increasing gearbox into electric power.

[0033] The hub 140 is coupled to a portion of the transmission shaft 130 that is located outside the nacelle 160. The hub 140 and the transmission shaft 130 rotate integrally.

[0034] like Figure 1 As shown, a plurality of blades 150 are coupled to the hub 140. Thus, the plurality of blades 150 are coupled to the nacelle 160 via the hub 140. The number of blades 150 is, for example, three. The blades 150 extend outward from the hub 140 in a radial direction centered on the roll axis R. The plurality of blades 150 are arranged at equal intervals in a circumferential direction centered on the roll axis R. The plurality of blades 150 are rotatable together with the hub 140 about the roll axis R as the rotational axis.

[0035] <Drive device>

[0036] like Figure 2 As shown, the wind turbine generator 100 has four drive devices 50. The four drive devices 50 are located on the outside of the ring gear 210 in the radial direction with the yaw axis Y as the center. The four drive devices 50 are arranged at equal intervals in the circumferential direction with the yaw axis Y as the center. As will be described later, the four drive devices 50 are fixed to the nacelle 160. The structure of each drive device 50 and the method of fixing it to the nacelle 160 are the same. Therefore, the following is a description of the four drive devices 50. Figure 4 The details are described by taking a driving device 50 as an example. Figure 4 As shown, the wind turbine generator 100 includes a battery 330 and an inverter 69 for each drive device 50 as components associated with the drive device 50 .

[0037] like Figure 4 As shown, the drive device 50 includes a motor 60, a speed reducer 70, and a drive shaft 80. The motor 60 is an electric motor. It includes a first housing 62, a stator 64, a rotor 66, and an output shaft 68. The first housing 62 is located inside the nacelle 160. The first housing 62 is located near the lower wall 162 of the nacelle 160. The first housing 62 is cylindrical. The central axis J of the first housing 62 is approximately parallel to the yaw axis Y. The stator 64 is located inside the first housing 62. The stator 64 is fixed to the first housing 62. The stator 64 is cylindrical. Although not shown, coils are wound around the stator 64. The coils are electrically connected to the battery 330 via an inverter 69. The rotor 66 is located inside the stator 64. The rotor 66 is rotatable relative to the stator 64. The output shaft 68 is fixed to the rotor 66. The output shaft 68 rotates integrally with the rotor 66. The central axis J of the output shaft 68 is approximately aligned with the central axis J of the first housing 62. In this embodiment, axes coaxial with the central axis J of the first housing 62 are designated uniformly by the reference numeral J. The output shaft 68 rotates about its central axis J. The majority of the output shaft 68 is located within the first housing 62. Both ends of the output shaft 68 protrude outside the first housing 62. A bearing G1 is interposed between the portion of the output shaft 68 located closer to the first housing 62 along the central axis J and the inner surface of the first housing 62. The bearing G1 rotatably supports the output shaft 68.

[0038] The reducer 70 is located between the first housing 62 and the lower wall 162 of the nacelle 160. The reducer 70 includes a second housing 72 and a reduction mechanism 74. The second housing 72 includes a housing body 72A and a flange 72B. The housing body 72A is cylindrical. The center axis J of the housing body 72A is substantially consistent with the center axis J of the first housing 62. The housing body 72A is fixed to the first housing 62. The flange 72B is located at the lower end of the second housing 72. The flange 72B protrudes from the outer peripheral surface of the second housing 72. The flange 72B extends over the entire circumference of the housing body 72A. The lower surface of the flange 72B faces the lower wall 162 of the nacelle 160. The flange 72B is fixed to the lower wall 162 of the nacelle 160. This fixing structure will be described later.

[0039] The reduction mechanism 74 is located inside the housing main body 72A. The reduction mechanism 74 is coupled to the output shaft 68 of the motor 60. The reduction mechanism 74 is input with the torque of the output shaft 68 of the motor 60. The reduction mechanism 74 outputs the torque of the output shaft 68 of the motor 60, which is enlarged at a prescribed ratio, to the drive shaft 80. The reduction mechanism 74 is, for example, of an eccentric swing gear type or a planetary gear type. The reduction mechanism 74 can be of any type as long as it is a structure capable of enlarging and outputting the torque from the motor 60.

[0040] The drive shaft 80 is coupled to the reduction mechanism 74. The drive shaft 80 protrudes from the inside of the housing main body 72A to the outside. The central axis J of the drive shaft 80 is substantially identical to the central axis J of the output shaft 68 of the motor 60. The bearing G2 is interposed between the portion of the drive shaft 80 located inside the housing main body 72A and the inner surface of the housing main body 72A. The bearing G2 rotatably supports the drive shaft 80. The drive shaft 80 rotates with its central axis J as the center of rotation. The portion of the drive shaft 80 protruding to the outside of the housing main body 72A penetrates the penetration hole 162A provided to the lower wall 162 of the nacelle 160. The end portion of the portion of the drive shaft 80 protruding to the outside of the housing main body 72A is located within the range of the ring gear 210 in the direction along the central axis J of the drive shaft 80.

[0041] The fixed configuration of the second housing 72 relative to the nacelle 160 will be described. The second housing 72 is fixed to the lower wall 162 of the nacelle 160 by a plurality of fixing devices 30. In Figure 4 In the figure, two of the plurality of fixing devices 30 are shown as representative. The plurality of fixing devices 30 are located at the flange 72B. The plurality of fixing devices 30 are arranged at equal intervals in the circumferential direction centered on the central axis J of the housing main body 72A. The structure and function of each fixing device 30 are identical. Therefore, the details of one fixing device 30 will be described below as an example.

[0042] The fixing device 30 is composed of a bolt 32 and a nut 34. The bolt 32 penetrates the flange 72B and the lower wall 162 of the nacelle 160. The head 32A of the bolt 32 is located at the upper surface of the flange 72B. The end portion of the bolt 32 on the side opposite the head 32A protrudes downward from the lower wall 162 of the nacelle 160. The nut 34 is installed to the end portion of the bolt 32 on the side opposite the head 32A. As a result, the flange 72B and the lower wall 162 of the nacelle 160 are fixed.

[0043] Here, as described above, the second housing 72 is fixed to the first housing 62. In other words, the second housing 72 is integral with the first housing 62. Furthermore, the second housing 72 is fixed to the nacelle 160 by bolts 32. Therefore, the motor 60, including the first housing 62, is also fixed to the nacelle 160 by these bolts 32. These bolts 32 for fixing the motor 60 to the nacelle 160 are provided not only for each motor 60 but also for each drive device 50.

[0044] <Pinion>

[0045] like Figure 2 As shown, the wind turbine generator 100 includes a plurality of pinions 220. A pinion 220 is provided for each drive unit 50. The mounting method of each pinion 220 relative to the drive unit 50 is the same. Figure 4 A small gear 220 is shown as an example to explain the details.

[0046] like Figure 4 As shown, the pinion 220 is mounted on the end of the portion of the drive shaft 80 that protrudes to the outside of the housing body 72A. The pinion 220 is cylindrical. The drive shaft 80 is inserted into the hole in the center of the pinion 220. The center axis J of the pinion 220 is roughly consistent with the center axis J of the drive shaft 80. The pinion 220 rotates integrally with the drive shaft 80. There are a plurality of teeth 222 on the outer peripheral surface of the pinion 220. The plurality of teeth 222 are arranged at equal intervals in the circumferential direction with the center axis J of the pinion 220 as the center. The outer peripheral surface of the pinion 220 faces the outer peripheral surface of the ring gear 210. The teeth 222 of the pinion 220 mesh with the teeth 212 of the ring gear 210. In addition, Figure 4 , only a portion of the plurality of teeth 212 of the ring gear 210 is shown. The pinion gear 220 and the ring gear 210 constitute the gear mechanism 200 for coupling the tower 110 and the nacelle 160 so as to be relatively rotatable.

[0047] Here, the power transmission process involved in the relative rotation of the nacelle 160 with respect to the tower 110 is described. The motor 60 can output a driving force for rotating the nacelle 160 relative to the tower 110. When the output shaft 68 of the motor 60 rotates, the drive shaft 80 rotates together with the output shaft 68. At the same time, as shown by Figure 2 As shown by the arrow A1, the pinion 220 rotates. At this time, the pinion 220 rotates around the ring gear 210 while rotating. Figure 2 As shown by arrow A2 , the nacelle 160 rotates relative to the tower 110 about the yaw axis Y. In other words, the yaw axis Y is the central axis of rotation of the nacelle 160 .

[0048] <Electromagnetic brake>

[0049] like Figure 2 As shown in FIG. 1 , the wind turbine generator 100 includes a plurality of electromagnetic brakes 310. The electromagnetic brake 310 is an electromagnetic brake that utilizes electromagnetic force. An electromagnetic brake 310 is provided for each drive unit 50. The structures of the electromagnetic brakes 310 are the same. Figure 4 An electromagnetic brake 310 is shown as an example to explain the details.

[0050] like Figure 4 As shown, the electromagnetic brake 310 is located on the opposite side of the reducer 70 across the motor 60. The electromagnetic brake 310 includes a third housing 312, a contact plate 314, a movable plate 316, an electromagnet 320, and a relay 325. The third housing 312 is cylindrical. The center axis J of the third housing 312 is substantially aligned with the center axis J of the first housing 62 of the motor 60. The upper end of the third housing 312, which is one side along the direction of the center axis J, is blocked. The lower end of the third housing 312 is fixed to the first housing 62. A portion of the output shaft 68 of the motor 60 is located inside the third housing 312.

[0051] Contact plate 314, movable plate 316, and electromagnet 320 are located within third housing 312. Contact plate 314 is located closer to first housing 62 along the central axis J of third housing 312. Contact plate 314 is circular. The output shaft 68 of motor 60 extends through near the center of contact plate 314. Contact plate 314 rotates integrally with output shaft 68.

[0052] The electromagnet 320 is located on the opposite side of the first housing 62 across the contact plate 314. Although not shown in detail, the electromagnet 320 includes an electromagnet body, a coil, and a spring. The electromagnet body is fixed to the third housing 312. The coil and spring are built into the electromagnet body.

[0053] Movable plate 316 is located between contact plate 314 and electromagnet 320. Movable plate 316 is disc-shaped. A hole is formed in the center of movable plate 316. The diameter of this hole is larger than the diameter of output shaft 68 of motor 60. Furthermore, output shaft 68 is inserted through this hole. Movable plate 316 is movable in a direction along the central axis J of output shaft 68.

[0054] Relay 325 is located midway along power line 329, which connects the coil of electromagnet 320 to battery 330. The presence or absence of power to the coil of electromagnet 320 is switched by the on / off switching of relay 325. Electromagnet 320 changes the position of movable plate 316 depending on whether the coil is energized. When the coil is not energized, electromagnet 320 uses the elastic force of the spring to move movable plate 316 away from the main body of the electromagnet. At this time, the spring presses movable plate 316 against contact plate 314. This applies a braking force not only to contact plate 314 but also to the output shaft 68 of motor 60, thereby slowing the rotation of output shaft 68. In other words, movable plate 316 applies a braking force to output shaft 68. On the other hand, when the coil is energized, electromagnet 320 resists the elastic force of the spring, attracting movable plate 316 toward the main body of the electromagnet. Consequently, movable plate 316 is positioned away from contact plate 314. In this case, the braking force on the contact plate 314 and the output shaft 68 of the motor 60 is released.

[0055] <Friction brake>

[0056] like Figure 3 As shown, the wind turbine generator 100 includes a hydraulic friction brake 350 . The friction brake 350 is a so-called disc brake and includes an extension wall 370 , a connecting member 354 , a pair of friction members 356 , and a hydraulic pressure supply mechanism 360 .

[0057] The extension wall 370 protrudes from the outer surface of the tower 110. The extension wall 370 is located near the upper wall 112 of the tower 110. The extension wall 370 extends over the entire area of ​​the tower 110 in the circumferential direction centered on the yaw axis Y.

[0058] The connecting member 354 is fixed to the lower wall 162 of the nacelle 160. The connecting member 354 holds a pair of friction members 356. The friction members 356 are positioned one above the other across the extension wall 370. The friction members 356 receive hydraulic pressure from a hydraulic pressure supply mechanism 360. This mechanism includes a pump, a valve that switches the oil circuit, and other components. The position of the friction members 356 changes depending on whether hydraulic pressure is supplied. When receiving hydraulic pressure, the friction members 356 approach each other. In this situation, the friction members 356 sandwich the extension wall 370. The friction force acting between the friction members 356 and the extension wall 370 acts as a braking force to stop the relative rotation of the nacelle 160 relative to the tower 110. In other words, the friction brake 350 applies a braking force to the tower 110 and nacelle 160 to stop their relative rotation. Alternatively, the friction brake 350 applies a braking force to the relative rotation of the nacelle 160 relative to the tower 110. The pair of friction members 356 move away from each other when no hydraulic pressure is supplied. Consequently, the pair of friction members 356 are positioned away from the extension wall 370. In this case, the braking force associated with the relative rotation of the nacelle 160 with respect to the tower 110 is released.

[0059] <Sensor>

[0060] like Figure 2 and Figure 5 As shown in FIG. 1 , the wind turbine generator 100 includes a plurality of strain sensors 21. Figure 5 In FIG. 1 , one strain sensor among a plurality of strain sensors 21 is representatively shown. The strain sensor 21 is a torque information sensor for detecting strain as information related to torque. Figure 2 As shown in FIG. 5 , a strain sensor 21 is provided for each drive device 50. That is, a strain sensor 21 is provided for each motor 60. The configuration and function of each strain sensor 21 are the same. Figure 4 A strain sensor 21 is shown as an example to explain the details.

[0061] Any one of the plurality of bolts 32 used to fix a certain drive device 50 to the nacelle 160 is referred to as a detection target bolt. Figure 4 As shown in FIG, the strain sensor 21 is located near the bolt to be detected. Figure 4 In FIG. 1 , a strain sensor 21 is shown at the head 32A of the bolt 32. The strain sensor 21 is fixed to the lower wall 162 of the nacelle 160 by a retaining fixture 95. The strain sensor 21 detects the strain H of the bolt to be detected. Figure 5 As shown, the strain sensor 21 repeatedly outputs its own detection value to the control unit 500 described later.

[0062] Here, regarding the bolt to be inspected, it can be said as follows. Figure 4 As shown, the detection target bolt is a bolt used to connect the drive device 50 to the nacelle 160. Furthermore, as described above, the pinion 220 is connected to the drive shaft 80 of the drive device 50. That is, the detection target bolt connects not only the drive device 50 but also the pinion 220 to the nacelle 160. In other words, the detection target bolt connects the gear mechanism 200 composed of the pinion 220 and the ring gear 210 to the nacelle 160. Furthermore, a plurality of such detection target bolts are arranged in a circumferential direction centered on the yaw axis Y, in accordance with the balance with the position of each drive device 50. A strain sensor 21 is provided corresponding to each of these plurality of detection target bolts.

[0063] like Figure 2 and Figure 5 As shown, wind turbine generator 100 includes a wind speed sensor 22 as a speed detection sensor for detecting the speed of wind passing through nacelle 160. Wind speed sensor 22 is mounted on the upper surface of nacelle 160. Wind speed sensor 22 detects the speed of wind passing through the upper surface of nacelle 160 as a passing wind speed V. Passing wind speed V detected by wind speed sensor 22 reflects the speed of wind passing through blades 150. Wind speed sensor 22 repeatedly outputs its own detection value to control unit 500, described later.

[0064] like Figure 2 and Figure 5 As shown, wind turbine generator 100 includes wind direction sensor 23. Wind direction sensor 23 is attached to the upper surface of nacelle 160. Wind direction sensor 23 detects the direction W of wind passing through the upper surface of nacelle 160. Wind direction sensor 23 repeatedly outputs its detection value to control unit 500 described below.

[0065] <Control Unit>

[0066] like Figure 2 and Figure 5 As shown, the wind turbine generator 100 includes a control unit 500. The control unit 500 is located inside the nacelle 160. Figure 5 As shown, the control unit 500 includes a processing circuit 501. Although not shown, the control unit 500 also includes a communication device for wireless or wired communication with the outside world, a communication port for acquiring information from various sensors, and the like. The control unit 500, together with the strain sensors 21, wind speed sensor 22, and wind direction sensor 23, constitutes a control device 600.

[0067] The processing circuit 501 includes a CPU 510 and a memory 520. The memory 520 includes three types of storage media: RAM, ROM, and electrically rewritable nonvolatile memory. In this embodiment, these three types of storage media are collectively referred to as the memory 520. The memory 520 pre-stores a control program N1 for the wind turbine generator 100 that describes various processes to be executed by the CPU 510, as well as various reference data N2 required by the CPU 510 when executing the control program N1.

[0068] The CPU 510 controls various parts of the wind turbine generator 100. For example, the CPU 510 controls the generator 170, the motors 60 of the drive devices 50, the electromagnetic brakes 310, and the friction brakes 350.

[0069] <Basic Control>

[0070] The CPU 510 is basically always running except when it is being maintained by the operator. The CPU 510 continuously performs basic control during its own operation. Basic control is the control related to the power generation of the generator 170. In the basic control, the CPU 510 repeatedly obtains the latest detection value from the wind speed sensor 22. In other words, the CPU 510 repeatedly obtains the latest passing wind speed V. When the power generation conditions are met, the CPU 510 controls the generator 170 to the operating state. Figure 6 As shown, the power generation condition is that the wind speed V is greater than the allowable lower limit V1 and less than the allowable upper limit V2. The allowable lower limit V1 is predetermined by taking into account the minimum wind speed that can rotate the blades 150. The allowable upper limit V2 is predetermined by taking into account the load imposed on each device in the power transmission path from the generator 170 to the blades 150. Figure 6 As shown by the solid line, CPU 510 controls generator 170 to achieve a substantially constant power generation amount P during the operation of generator 170, except when wind speed V is low. Furthermore, memory 520 pre-stores a permissible lower limit value V1 and a permissible upper limit value V2. Permissible lower limit value V1 and permissible upper limit value V2 are one type of reference data N2.

[0071] <Brake Control>

[0072] The CPU 510 repeatedly executes braking control during the operation of the generator 170. The braking control is a control for braking the relative rotation of the nacelle 160 with respect to the tower 110. Next, a series of processes executed by the CPU 510 in the braking control will be described.

[0073] like Figure 7As shown, when the CPU 510 starts the braking control, it first executes the process of step S300. In step S300, the CPU 510 determines whether the motor 60 is stopped due to the relationship with the driving control described later. If the motor 60 is stopped (step S300: "YES"), the CPU 510 advances the process to step S310.

[0074] In step S310, the CPU 510 determines whether the latest passing wind speed V is less than or equal to the set value VM. The memory 520 pre-stores the set value VM. The set value VM is a type of reference data N2. The set value VM is predetermined, for example, by experiments or simulations, as the maximum value of the passing wind speed V at which the nacelle 160 can be maintained at the rotational position at the current time point by only the electromagnetic brake 310 of the electromagnetic brake 310 and the friction brake 350. When making the determination in step S310, the CPU 510 first obtains the latest passing wind speed V detected by the wind speed sensor 22. In essence, the CPU 510 refers to the latest value of the passing wind speed V repeatedly obtained in the basic control. When the CPU 510 obtains the latest passing wind speed V, it compares the passing wind speed V with the set value VM. If the latest passing wind speed V is less than or equal to the set value VM (step S310: "Yes"), the CPU 510 advances the processing to step S320.

[0075] In step S320, the CPU 510 puts the electromagnetic brake 310 into the driving state. That is, the CPU 510 controls the relay 325 so that the braking force of the electromagnetic brake 310 acts on the motor 60. In the present embodiment, the CPU 510 disconnects the relay 325. After putting the electromagnetic brake 310 into the driving state, the CPU 510 terminates the processing of step S320 while maintaining the driving state. The processing time required by the CPU 510 in step S320 is, for example, less than one second. This also applies to steps S330 and S340, which will be described later. Furthermore, regarding the processing of step S320, the CPU 510 may have already put the electromagnetic brake 310 into the driving state at the time the processing enters step S320 due to its connection with the braking control processing of the previous cycle. In this case, the CPU 510 directly maintains the driving state of the electromagnetic brake 310 in step S320. When the CPU 510 terminates the processing of step S320, it temporarily ends the series of braking control processing. After that, CPU 510 immediately starts the next cycle of braking control. That is, CPU 510 executes the process of step S300.

[0076] On the other hand, if the latest passing wind speed V is greater than the set value VM in step S310 (step S310: No), the CPU 510 advances the process to step S330. In this case, the CPU 510 activates both the electromagnetic brake 310 and the friction brake 350. The details of the process for activating the electromagnetic brake 310 are the same as those described in step S320. The CPU 510 controls the hydraulic pressure supply mechanism 360 for the friction brake 350 so that the braking force of the friction brake 350 acts on the tower 110 and the nacelle 160. Similar to step S320, if both the electromagnetic brake 310 and the friction brake 350 are already being activated when the process advances to step S330, the CPU 510 maintains these activations. If both the electromagnetic brake 310 and the friction brake 350 are activated, the CPU 510 terminates the process of step S330, maintaining these activations. Then, the CPU 510 temporarily ends the series of processes for the braking control. Thereafter, the CPU 510 quickly starts the next cycle of the braking control. That is, the CPU 510 executes the process of step S300.

[0077] Then, if the motor 60 is being driven in step S300 (step S300: No), the CPU 510 advances the process to step S340. In this case, the CPU 510 in step S340 places both the electromagnetic brake 310 and the friction brake 350 in a non-driven state. That is, the CPU 510 controls the relay 325 so that the braking force of the electromagnetic brake 310 on the motor 60 is released. In the present embodiment, the CPU 510 turns on the relay 325. In addition, the CPU 510 controls the hydraulic supply mechanism 360 so that the braking force of the friction brake 350 on the tower 110 and the nacelle 160 is released. If both the electromagnetic brake 310 and the friction brake 350 are in a non-driven state at the time the process enters step S340, the CPU 510 maintains this state. When both electromagnetic brake 310 and friction brake 350 are in the non-actuated state, CPU 510 terminates the process of step S340 while maintaining this state. CPU 510 then temporarily terminates the series of braking control processes. Thereafter, CPU 510 quickly begins the next cycle of braking control. In other words, CPU 510 executes the process of step S300.

[0078] Regarding the braking control described above, the CPU 510 repeatedly performing step S320 to maintain the electromagnetic brake 310 in its actuated state, and the CPU 510 repeatedly performing step S330 to maintain the actuated states of both the electromagnetic brake 310 and the friction brake 350, constitutes the braking process. Specifically, during the braking process, the CPU 510 brakes the relative rotation of the nacelle 160 relative to the tower 110 by actuating at least one of the electromagnetic brake 310 and the friction brake 350. In the following description, the electromagnetic brake 310 and the friction brake 350 are collectively referred to as "brakes."

[0079] <Drive Control>

[0080] The CPU 510 repeatedly executes drive control while the generator 170 is operating. Drive control is used to drive the relative rotation of the nacelle 160 with respect to the tower 110. The following describes the series of processes executed by the CPU 510 during drive control. Furthermore, the CPU 510 stops energizing the motor 60 at the start of generator 170 operation. In other words, the motor 60 stops at the start of generator 170 operation by the CPU 510.

[0081] like Figure 8 As shown, when the CPU 510 begins driving control, it first executes the process of step S100. In step S100, the CPU 510 acquires the torque parameter T. The torque parameter T is a parameter that is positively correlated with the load torque HT. The load torque HT will be described in the "Operation" section of the embodiment described later. When acquiring the torque parameter T, the CPU 510 first acquires the latest detection values ​​from each of the multiple strain sensors 21. Specifically, the CPU 510 acquires the latest values ​​for the strain H of the bolt 32 from each of the multiple strain sensors 21. The CPU 510 then calculates the average of these multiple acquired values. The CPU 510 then processes the obtained average value as the torque parameter T. Calculating the average value is an example of statistical processing. Upon acquiring the torque parameter T, the CPU 510 proceeds to step S110. Furthermore, the process of step S100 is an acquisition process. Specifically, in the acquisition process, the CPU 510 acquires the detection values ​​of the strain sensors 21 and acquires the torque parameter T based on these detection values.

[0082] In step S110, the CPU 510 determines whether the torque parameter T obtained in step S100 is greater than the first threshold value T1. The memory 520 pre-stores the first threshold value T1. The first threshold value T1 is a type of reference data N2. The specific value of the first threshold value T1 is described in the column of the function of the embodiment described later. When the torque parameter T obtained in step S100 is less than the first threshold value T1 (step S110: "No"), the CPU 510 returns to the processing of step S100. On the other hand, when the torque parameter T is greater than the first threshold value T1 (step S110: "Yes"), the CPU 510 causes the processing to enter step S120. In addition, the CPU 510 controls the brake to a driving state during the execution of steps S110 and S120 due to the association with the above-mentioned braking control.

[0083] In step S120, the CPU 510 begins driving the motors 60 in each drive device 50. Specifically, the CPU 510 begins energizing each motor 60 to start rotating the output shaft 68 of each motor 60. Furthermore, when driving each motor 60, the CPU 510 essentially controls the inverter 69 of each motor 60. When the CPU 510 begins driving each motor 60, the nacelle 160 begins rotating relative to the tower 110. Upon starting to drive each motor 60, the CPU 510 proceeds to step S130. Furthermore, due to its connection with the aforementioned brake control, the CPU 510 subsequently controls the brakes to a non-actuated state until the processing of step S150 is completed.

[0084] In step S130 , CPU 510 performs the acquisition process described in step S100 . That is, in step S130 , CPU 510 again acquires torque parameter T. Thereafter, CPU 510 advances the process to step S140 .

[0085] In step S140, the CPU 510 determines whether the torque parameter T obtained in step S130 is less than the second threshold value T2. The memory 520 pre-stores the second threshold value T2. The second threshold value T2 is a type of reference data N2. The second threshold value T2 is predetermined to be a value smaller than the first threshold value T1. The specific value of the second threshold value T2 is described in the column of the function of the embodiment described later. When the torque parameter T obtained in step S130 is greater than the second threshold value T2 (step S140: "No"), the CPU 510 returns to the processing of step S130. On the other hand, when the torque parameter T obtained in step S130 is less than the second threshold value T2 (step S140: "Yes"), the CPU 510 advances the processing to step S150.

[0086] In step S150, the CPU 510 stops the motor 60 of each drive device 50. That is, the CPU 510 stops the rotation of the output shaft 68 in each motor 60 by stopping the power supply to each motor 60. The CPU 510 then ends the processing of step S150. At the same time, the CPU 510 temporarily ends the series of processes related to the drive control. Thereafter, the CPU 510 quickly starts the next cycle of drive control. That is, the CPU 510 starts the processing of step S100. In addition, the series of processes from the time the CPU 510 determines "yes" in step S110 to the end of step S150 is the drive processing.

[0087] Here, the CPU 510 is capable of rotating the output shaft 68 of the motor 60 in both forward and reverse directions. Strictly speaking, regarding the above-mentioned drive processing, the CPU 510 performs the following processing. That is, in step S120, the CPU 510 rotates the output shaft 68 of the motor 60 in a predetermined first rotation direction. If the torque parameter T does not decrease temporarily after starting to drive the motor 60, the CPU 510 reverses the rotation direction of the output shaft 68. Then, the CPU 510 continues to drive the motor 60 as described above until the torque parameter T is below the second threshold value T2. In addition, the CPU 510 can also determine the rotation direction of the output shaft 68 of the motor 60 based on the detection value of the wind direction sensor 23.

[0088] <Function 1 of Embodiment: Overall Flow of Processing Performed by the CPU>

[0089] The CPU 510 performs the braking control and the driving control in a manner linked to each other during the operation of the generator 170. The overall flow of the processing performed by the CPU 510 regarding the braking control and the driving control will be summarized below.

[0090] Currently, it is assumed that the CPU 510 does not drive the motor 60 (step S300: "Yes") but instead drives the brake (step S320 or step S330). That is, the CPU 510 stops the rotation of the nacelle 160. The CPU 510 repeatedly calculates the torque parameter T while the brake is being driven, thereby monitoring the change in the torque parameter T (steps S100 and S110: "No"). Then, when the torque parameter T is greater than the first threshold value T1 (step S110: "Yes"), the CPU 510 releases the brake (step S340). On the other hand, when the torque parameter T is greater than the first threshold value T1, the CPU 510 drives the motor 60 (step S120) to rotate the nacelle 160 relative to the tower 110 until the torque parameter T is less than the second threshold value T2. That is, the CPU 510 executes the drive process. When the torque parameter T is less than the second threshold value T2 (step S140: "Yes"), the CPU 510 stops the motor 60 (step S150). At the same time, the CPU 510 drives the brake to maintain the rotational position of the nacelle 160 at the current time point (step S320 or step S330). That is, the CPU 510 performs a braking process. When the nacelle 160 is maintained at the rotational position at the current time point, when the passing wind speed V is low (step S310: "Yes"), the CPU 510 drives only the electromagnetic brake 310 (step S320). On the other hand, when the passing wind speed V is high (step S310: "No"), the CPU 510 drives both the electromagnetic brake 310 and the friction brake 350 (step S330).

[0091] Next, assume that the wind direction changes while CPU 510 is holding the rotational position of nacelle 160 by actuating the brake. Consequently, for reasons described below, torque parameter T increases. When torque parameter T exceeds first threshold value T1 (step S110: YES), CPU 510 drives motor 60 again and releases the brake. CPU 510 then rotates nacelle 160 until torque parameter T falls below second threshold value T2 (step S140: YES). Thereafter, CPU 510 actuates the brake to hold nacelle 160 in its rotated position.

[0092] In this way, the CPU 510 repeatedly performs the driving process and the braking process alternately during the operation of the generator 170. At the same time, the CPU 510 selects a brake to be used according to the passing wind speed V in the braking process.

[0093] <Effect 2 of Embodiment: Detection Value of Strain Sensor>

[0094] The relationship between the strain H of the bolt 32 detected by the strain sensor 21 and the direction of the wind acting on the blade 150 will be described in detail. Figure 2 As shown, the direction in the radial direction centered on the yaw axis Y, along the roll axis R (i.e., along the roll axis R in a plane perpendicular to the yaw axis Y), and from the side opposite to the nacelle 160 across the hub 140 toward the blade 150 is referred to as the first direction D1. Furthermore, the direction of the wind with respect to the blade 150 in the radial direction centered on the yaw axis Y (i.e., the direction of the wind with respect to the blade 150 in a plane perpendicular to the yaw axis Y) is referred to as the second direction D2. Furthermore, the acute angle formed by the first direction D1 and the second direction D2 is referred to as the offset angle DA.

[0095] Currently, it is assumed that the CPU 510 does not drive the motor 60 but maintains the nacelle 160 at a certain rotational position through the electromagnetic brake 310. In this situation, it is assumed that the wind direction changes and the offset angle DA increases. If the offset angle DA is zero, a force in a direction consistent with the roll axis R, that is, a force in a direction orthogonal to the blades 150, acts on the plurality of blades 150 when the plurality of blades 150 are viewed as a whole. On the other hand, when the offset angle DA is large, a force in a direction intersecting the roll axis R, that is, a force in a direction not orthogonal to the blades 150, acts on the blades 150. Then, the blades 150 are pushed by the wind to increase the offset angle DA. That is, as shown by Figure 2 As shown by the arrow B, the blade 150 is subjected to a force that wants to rotate the blade 150 in the circumferential direction around the yaw axis Y. This force acts on the nacelle 160 connected to the blade 150. That is, the nacelle 160 wants to rotate in the circumferential direction around the yaw axis Y. Figure 4 As shown, the force acting on the nacelle 160 is transmitted to the second housing 72 via the bolts 32 connecting the nacelle 160 to the drive unit 50. If the pinion gear 220 were in a rotatable state at this point, it would rotate relative to the ring gear 210 due to the force from the nacelle 160. However, in reality, the electromagnetic brake 310 brakes not only the rotation of the output shaft 68 of the motor 60 but also the rotation of the pinion gear 220, preventing the pinion gear 220 from rotating. Consequently, a load is applied to the bolts 32 connecting the nacelle 160, which is intended to rotate, and the drive unit 50, which is intended to inhibit such rotation. Consequently, the bolts 32 are strained. The strain sensor 21 detects this strain H of the bolts 32. Specifically, the value detected by the strain sensor 21 reflects the torque, or load torque HT, acting from the nacelle 160 on the pinion gear 220 when the electromagnetic brake 310 holds the nacelle 160 in a fixed position. Therefore, the detection value of the strain sensor 21 is information related to the load torque HT. Figure 9As shown, the detection value of the strain sensor 21 is positively correlated with the load torque HT. Figure 9 This is an example of the correspondence between the load torque HT and the strain H of the bolt 32 calculated by experiments or simulations. Regarding the relationship between the load torque HT and the detection value of the strain sensor 21, the torque parameter T, which is the average value of the detection values ​​of the plurality of strain sensors 21, is positively correlated with the load torque HT.

[0096] Next, based on the aforementioned correspondence between the torque parameter T and the deviation angle DA, the processing performed by the CPU 510 during driving control and braking control will be re-explained. During driving control, when the torque parameter T increases, that is, when the deviation angle DA increases, the CPU 510 drives the motor 60. Consequently, the CPU 510 causes the nacelle 160 to rotate relative to the tower 110. Concomitantly, the CPU 510 gradually reduces the deviation angle DA toward zero. When the torque parameter T decreases sufficiently, that is, when the deviation angle DA decreases sufficiently, the CPU 510 stops the rotation of the nacelle 160. At the position where the CPU 510 stops the rotation of the nacelle 160, i.e., at a low deviation angle DA, the blades 150 can receive wind from approximately the front. During braking control, the CPU 510 brakes the rotation of the nacelle 160 at this position where the blades 150 can receive wind from approximately the front.

[0097] <Effect 3 of Embodiment: Regarding First and Second Thresholds>

[0098] The first threshold value T1 involved in the drive control is described. The first threshold value T1 is predetermined to be, for example, the following value. The virtual circle formed by the rotation trajectory of the outer edge of the blade 150 when the blade 150 rotates around the roll axis R is called the blade circle. Figure 2 The projected area of ​​the blade circle when looking down at the blade 150 in the first direction D1 described in FIG. 1 is referred to as the first area. Figure 2 The projected area of ​​the blade circle when looking down at blade 150 from the second direction D2 described above is referred to as the second area. Furthermore, the offset angle DA at which the second area is 90% of the first area is referred to as the critical angle. The first threshold value T1 is predetermined, for example, through experiments or simulations, to be the strain H of bolt 32 that allows for understanding when the offset angle DA exceeds the critical angle. In other words, the first threshold value T1 is determined to a value that maintains high power generation efficiency. Furthermore, high power generation efficiency means achieving a higher power generation amount P under the same environmental conditions and operating conditions of the generator 170.

[0099] The second threshold value T2 related to the driving control will be described. The second threshold value T2 is predetermined, for example, by experiments or simulations, to be the strain H of the bolt 32 that can be detected when the offset angle DA is substantially zero.

[0100] <Function 4 of the embodiment: Regarding the brake used in the braking process>

[0101] As described above, CPU 510 changes the brake to be utilized during the braking process based on the passing wind speed V. The reason for this will be explained below. As a prerequisite, the braking force of friction brake 350 is considerably stronger than that of electromagnetic brake 310. Furthermore, friction brake 350 brakes the movement of nacelle 160 itself. Therefore, if friction brake 350 is activated when the passing wind speed V is low, nacelle 160 will remain almost completely immobilized even if the deflection angle DA is large. Consequently, even with a large deflection angle DA, no strain H is generated in bolt 32, and torque parameter T remains substantially zero (step S110: "No"). In this case, the drive control settings prevent CPU 510 from driving motor 60 or rotating nacelle 160, resulting in a persistently large deflection angle DA. To avoid this situation, CPU 510 utilizes only electromagnetic brake 310 to maintain the rotational position of nacelle 160 when the passing wind speed V is low. If only the electromagnetic brake 310 is actuated, the bolt 32 generates a strain H according to the offset angle DA. Thus, the CPU 510 can adjust the rotational position of the nacelle 160 according to the offset angle DA. Furthermore, if the passing wind speed V is low, the CPU 510 can maintain the rotational position of the nacelle 160 using only the braking force of the electromagnetic brake 310.

[0102] When the passing wind speed V is high, it is difficult to maintain the current rotational position of nacelle 160 using only the electromagnetic brake 310. Therefore, when the passing wind speed V is high, CPU 510 utilizes both the electromagnetic brake 310 and the friction brake 350 to maintain the rotational position of nacelle 160. However, when the passing wind speed V is high, the friction brake 350 alone cannot completely block the force that would cause nacelle 160 to rotate. Therefore, when the passing wind speed V is high, even when both the electromagnetic brake 310 and the friction brake 350 are utilized, the bolt 32 generates a strain H based on the deflection angle DA. Simultaneously, the torque parameter T increases. Therefore, when the passing wind speed V is high, even when both the electromagnetic brake 310 and the friction brake 350 are utilized, the rotational position of nacelle 160 can be adjusted based on the deflection angle DA.

[0103] <Effects of Implementation>

[0104] (1) As described above, when the torque parameter T increases, that is, the deviation angle DA increases, the CPU 510 rotates the nacelle 160 until the torque parameter T decreases sufficiently. Therefore, the CPU 510 can quickly decrease the deviation angle DA at each timing in accordance with the direction of the wind received by the blades 150.

[0105] To determine the drift angle DA, one approach is to use the detection value of the wind direction sensor 23. However, using the detection value of the wind direction sensor 23 presents the following problem. The wind direction sensor 23 is located downwind of the blades 150. Therefore, the wind reaching the wind direction sensor 23 may become turbulent or change direction as it passes through the blades 150. Consequently, the detection value of the wind direction sensor 23 may differ from the actual direction of the wind received by the blades 150. Therefore, it is difficult to determine the real-time drift angle DA using the detection value of the wind direction sensor 23. To mitigate the impact of instantaneous wind direction fluctuations included in the detection value of the wind direction sensor 23, one approach is to refer to the average value of the detection value of the wind direction sensor 23 over a predetermined period of time, such as 10 minutes. However, referring to this average value over a predetermined period of time does not allow for determining the instantaneous drift angle DA at each specific moment. Furthermore, if the rotational position of the nacelle 160 is adjusted at predetermined intervals based on this average value, the situation in which the drift angle DA increases and the power generation P decreases during the predetermined period of time will persist.

[0106] In this regard, the CPU 510 of this embodiment can grasp not only the real-time load torque HT but also the deviation angle DA by using the detection value of the strain sensor 21. Therefore, the CPU 510 can rotate the nacelle 160 to the rotation position most suitable for power generation at each timing. Moreover, the blades 150 can almost always receive wind from almost directly in front. In this case, as shown by Figure 6 As shown by the solid line, compared with the case where the rotation position of nacelle 160 is adjusted at predetermined intervals based on the value obtained by averaging the detection values ​​of wind direction sensor 23 at predetermined intervals ( Figure 6 ), the target power generation amount P increases under the same wind speed V. That is, in the configuration of this embodiment, the power generation efficiency of the wind turbine generator 100 increases.

[0107] Also, in the structure of the present embodiment, due to the association with the allowable upper limit value V2 involved in the power generation condition, it is possible as follows. That is, in the case where it is premised that the rotation of the nacelle 160 is controlled based on a value obtained by averaging the detection values of the wind direction sensor 23 at every prescribed time, the allowable upper limit value V2A needs to be set in advance to a value in which the deflection angle DA is expected to possibly increase within the prescribed time. That is, in a case where it is expected that the power generation amount P of the generator 170 will decrease due to the deflection angle DA increasing within the prescribed time, the allowable upper limit value V2A needs to be set low in accordance with the balance of effects against costs such as power consumption involved in the operation of the generator 170 and the burden imposed on each device. In this case, the range of the passing wind speed V at which the generator 170 can be operated narrows. In this regard, in the structure of the present embodiment in which the rotational position of the nacelle 160 can be adjusted in accordance with the real-time deflection angle DA, the decrease in the power generation amount P does not occur at each passing wind speed V, so the allowable upper limit value V2 can be set to the value of the maximum limit allowed. Along with this, the region of the passing wind speed V at which the generator 170 can be operated can be expanded. Therefore, in the structure of the present embodiment, it is possible to secure more power generation amount P under the same environmental conditions.

[0108] (2) The CPU 510 of the present embodiment uses the detection value of the strain sensor 21 as an index of the load torque HT. Here, as an index of the load torque HT, for example, it is also considered to use the amount of rotation of the output shaft 68 or the drive shaft 80 of the motor 60 or the like. However, the amount of rotation of these output shaft 68 or drive shaft 80 involved in the load torque HT is extremely small. Even if it is intended to make the information of such an extremely small amount of rotation correspond to the load torque HT, it is difficult to grasp the correspondence between the amount of rotation and the load torque HT with high precision. In this regard, it can be said that the detection value of the strain sensor 21 directly reflects the load torque HT. Thus, the CPU 510 of the present embodiment, which uses the detection value of the strain sensor 21 as an index of the load torque HT, can grasp the deflection angle DA and rotate the nacelle 160 with the same degree of precision as that of actually detecting the load torque HT itself.

[0109] (3) In this embodiment, the plurality of drive devices 50 are arranged at different positions in the circumferential direction centered on the yaw axis Y. Due to the differences in the positions of the drive devices 50, the magnitude of the load torque HT acting from the nacelle 160 on the gear mechanism 200 may slightly differ depending on the position of the drive devices 50. Furthermore, this may lead to errors in the detection values ​​of the plurality of strain sensors 21. Furthermore, due to individual differences between the strain sensors 21, errors may also occur in the detection values ​​of the plurality of strain sensors 21. Based on this, the CPU 510 of this embodiment calculates the average value of the detection values ​​of the plurality of strain sensors 21 as the torque parameter T. Averaging the detection values ​​of the plurality of strain sensors 21 is highly likely to cancel out the aforementioned errors. Using this average value, the CPU 510 of this embodiment can more appropriately adjust the rotational position of the nacelle 160 from the perspective of improving power generation efficiency.

[0110] (4) The CPU 510 of this embodiment changes the brake to be used according to the magnitude of the passing wind speed V. As described in the column "Action 4" of the above embodiment, the CPU 510 can rotate the nacelle 160 to a position optimal for power generation or maintain the nacelle 160 in that rotational position, regardless of the magnitude of the passing wind speed V.

[0111] <Change Example>

[0112] The above embodiment can be modified and implemented as follows. The above embodiment and the following modified examples can be combined with each other within the scope of no technical contradiction.

[0113] The torque parameter T obtained in the acquisition process is not limited to the example of the above-mentioned embodiment. The torque parameter T only needs to be a parameter that is positively correlated with the load torque HT. That is, the torque parameter T only needs to be a parameter that increases as the load torque HT increases. For example, the load torque HT itself can also be obtained as the torque parameter T. In this case, it is sufficient to store information indicating the correspondence between the strain H of the bolt 32 and the load torque HT in the memory 520 in advance as reference data N2. Then, the CPU 510 only needs to obtain the load torque HT corresponding to the detection value of the strain sensor 21 based on this information. In the case of changing the torque parameter T relative to the example of the above-mentioned embodiment, it is sufficient to change the first threshold value T1 and the second threshold value T2 to match the changed physical quantity.

[0114] · The offset angle DA may also be used as the torque parameter T. In this case, the following method may be considered as the processing content of the CPU 510 involved in the drive control. In addition, when the offset angle DA is used as the torque parameter T, as a prerequisite, the following corresponding information is pre-stored in the memory 520. The corresponding information is information indicating the corresponding relationship between the strain H of the bolt 32, the wind speed V, and the offset angle DA. The corresponding information is a type of reference data N2. Figure 10 As shown in FIG, the corresponding information shows the corresponding relationship between the offset angle DA and the strain H of the bolt 32 for each passing wind speed V. Figure 10 In the example, as a representative of the corresponding relationship for each passing wind speed V, the relationship between the offset angle DA and the strain H of the bolt 32 is shown with the first wind speed VX1 and the second wind speed VX2 as the objects. The first wind speed VX1 is greater than the second wind speed VX2. Figure 10 As shown, for a given passing wind speed V, the larger the offset angle DA, the greater the strain H of the bolt 32. Furthermore, for a given offset angle DA, the higher the passing wind speed V, the greater the strain H of the bolt 32. Such correspondence information is generated based on, for example, experiments or simulations. Alternatively, the correspondence information may be information that represents the correspondence between the offset angle DA and the load torque HT, in addition to the passing wind speed V, instead of the strain H of the bolt 32.

[0115] Then, the CPU 510 Figure 8 In the acquisition process of steps S100 and S130 of the driving control shown, the offset angle DA, serving as the torque parameter T, is acquired as follows. First, the CPU 510 acquires the latest detection values ​​from each of the multiple strain sensors 21. The CPU 510 then calculates the average of these acquired detection values ​​as the average strain. Furthermore, the CPU 510 acquires the latest detection value from the wind speed sensor 22. Based on the corresponding information, the CPU 510 then acquires the offset angle DA corresponding to the average strain and the latest passing wind speed V, as the offset angle DA corresponding to the current situation. In other words, the CPU 510 acquires the offset angle DA based on the average strain obtained by statistically processing the detection values ​​of the multiple strain sensors 21. In the driving control, the CPU 510 makes decisions in steps S110 and S140 based on the torque parameter T thus acquired. If the determination in step S110 is "yes," the CPU 510 drives the motor 60 in step S120. If the determination in step S140 is "YES," the CPU 510 in step S150 stops the motor 60. As described above, when the deviation angle DA is used as the torque parameter T, the first threshold value T1 and the second threshold value T2 are appropriately changed in advance accordingly.

[0116] When the offset angle DA is used as the torque parameter T, the CPU 510 can drive the motor 60 based on the offset angle DA itself. Therefore, the CPU 510 can more directly adjust the rotational position of the nacelle 160 to cancel the offset angle DA.

[0117] The definition of the first threshold value T1 is not limited to the example in the above embodiment. The first threshold value T1 may be appropriately determined by taking into account factors such as the frequency of the drive motor 60 and the size of the allowable deviation angle DA. The first threshold value T1 is not limited to a fixed value. Specifically, the first threshold value T1 may be variably set based on factors such as the passing wind speed V.

[0118] The definition of the second threshold value T2 is not limited to the example of the above embodiment. The second threshold value T2 only needs to be smaller than the first threshold value T1. Like the first threshold value T1, the second threshold value T2 is not limited to a fixed value.

[0119] The method of statistically processing the detection values ​​of the multiple strain sensors 21 is not limited to the examples in the above embodiment. For example, the statistical processing may include extracting the median, minimum, or maximum value of the detection values ​​of the multiple strain sensors 21, or performing a calculation that takes into account the variation in the detection values ​​of the multiple strain sensors 21. Any statistical processing may be used as long as it can extract characteristics understood from the detection values ​​of the multiple strain sensors 21.

[0120] When calculating the torque parameter T, it is not essential to use the detection values ​​of multiple strain sensors 21. In other words, the torque parameter T may be calculated based on the detection value of only one strain sensor 21. If the torque parameter T is calculated based on the detection value of only one strain sensor 21, it is not necessary to provide multiple strain sensors 21 in the wind turbine generator 100.

[0121] The torque information sensor is not limited to the example in the above embodiment. Any torque information sensor may be used as long as it can detect information related to the load torque HT. As described in a modified example below, a current sensor that detects the current value of the motor 60 may be used as the torque information sensor. When a sensor other than the strain sensor 21 is used as the torque information sensor, the strain sensor 21 may be eliminated from the wind turbine generator 100. When the torque information sensor is modified from the example in the above embodiment, the information related to the load torque HT acquired during the acquisition process also changes.

[0122] The structure of electromagnetic brake 310 is not limited to the example of the above embodiment. Electromagnetic brake 310 can be any structure as long as it can apply braking force to output shaft 68 of motor 60 using electromagnetic force. For example, electromagnetic brake 310 can also be a structure that applies braking force to output shaft 68 when relay 325 is turned on.

[0123] The structure of the friction brake 350 is not limited to the example of the above embodiment. The friction brake 350 can be used as long as it can apply a braking force to the tower 110 and nacelle 160 to prevent relative rotation thereof using fluid pressure. The fluid pressure is not limited to hydraulic pressure. For example, the fluid pressure may also be gas pressure.

[0124] To maintain the rotational position of nacelle 160, it is not essential to change the brake used based on the passing wind speed V. For example, if the braking force of friction brake 350 can be adjusted, friction brake 350 can be configured to exert a braking force sufficient to generate not only load torque HT but also strain H in bolt 32 even when the passing wind speed V is low. Furthermore, if a spring with a sufficiently high elastic force can be employed in electromagnetic brake 310 or the electromagnetic force can be sufficiently increased, the rotational position of nacelle 160 can be maintained using electromagnetic brake 310 alone even when the passing wind speed V is high.

[0125] The use of electromagnetic brake 310 or friction brake 350 is not essential for maintaining the rotational position of nacelle 160. For example, instead of using these brakes, the rotational position of nacelle 160 can be maintained by continuously energizing motor 60 and applying torque to motor 60's output shaft 68. With such a configuration, either or both electromagnetic brake 310 and friction brake 350 can be eliminated from wind turbine generator 100. Furthermore, when motor 60 is continuously energized while maintaining the rotational position of nacelle 160, the torque acting not only on output shaft 68 but also on pinion 220 can be determined based on the current flowing through motor 60. Therefore, wind turbine generator 100 can be provided with a current sensor that detects the current flowing through motor 60 and employs this current sensor as a torque information sensor. In this case, the current sensor detects the current flowing through motor 60 as information related to load torque HT.

[0126] The structure of the drive device 50 is not limited to that of the above-described embodiment. The drive device 50 only needs to include the motor 60 for driving the relative rotation of the nacelle 160 with respect to the tower 110. For example, the shape of the housing, the structure for securing the nacelle 160, and the like may be modified from those of the above-described embodiment.

[0127] The overall structure of the wind turbine generator 100 is not limited to the example embodiment described above. For example, the position and number of the drive devices 50 may be modified from those in the example embodiment described above. The structure of the nacelle 160 may also be modified from those in the example embodiment described above. For example, the nacelle 160 may include a hollow main body, a flat bottom wall located below the main body, and an intermediate wall connecting the main body and the bottom wall. Furthermore, in such a structure, the drive device 50 may be mounted on the bottom wall. In this case, the drive device 50 is exposed to the outside of the main body of the nacelle 160. The placement of the control unit 500 may also be modified from those in the example embodiment described above. For example, the control unit 500 may be located outside the nacelle 160, such as inside the tower 110. The structure of the gear mechanism 200 that connects the nacelle 160 and the tower 110 for relative rotation may also differ from those in the example embodiment described above. For example, the plurality of teeth 212 may be located on the inner circumferential surface of the ring gear 210 rather than on the outer circumferential surface. At the same time, the drive device 50 may be arranged radially inward of the ring gear 210 with respect to the yaw axis Y as the center. Alternatively, the ring gear 210 may be mounted on the nacelle 160, and the drive device 50 may be mounted on the tower 110. The structure of the gear mechanism 200 is not limited as long as the nacelle 160 and the tower 110 can be connected so as to be rotatable relative to each other. The wind turbine 100 only needs to have the nacelle 160 configured to rotate relative to the tower 110 and include the motor 60 for driving this relative rotation. The motor 60 is not limited to an electric motor.

[0128] The configuration of the control device 600 is not limited to the example in the above embodiment. The control device 600 only needs to include a sensor that detects information related to the load torque HT and a processing circuit 501 that controls the motor 60 for rotating the nacelle 160 relative to the tower 110. If the processing circuit 501 does not include processing that utilizes the detection value of the wind speed sensor 22, the wind speed sensor 22 can be omitted from the control device 600. The same applies to the wind direction sensor 23.

[0129] The processing content of the processing circuit 501 is not limited to the example of the above embodiment. As described above, the braking process that changes the brake to be used according to the wind speed V is not essential. Furthermore, if the motor 60 can be properly controlled even without the drive process, the drive process can be omitted. Furthermore, if the motor 60 can be properly controlled even without acquiring the torque parameter T, the acquisition process can be omitted. The processing content of the processing circuit 501 can be any content that drives the motor 60 for rotating the nacelle 160 relative to the tower 110 based on the detection value of the sensor that detects information related to the load torque HT.

[0130] The processing circuit 501 may have any one of the following structures (a) to (c).

[0131] (a) Processing circuit 501 includes one or more processors that execute various processes according to computer programs. The processors include a CPU and memory such as RAM and ROM. The memory stores program code or instructions that cause the CPU to execute the processes. Memory, or computer-readable media, includes any available media that can be accessed by a general-purpose or special-purpose computer.

[0132] (b) The processing circuit 501 includes one or more dedicated hardware circuits for executing various processes. Examples of the dedicated hardware circuit include application-specific integrated circuits, namely, ASICs and FPGAs.

[0133] (c) The processing circuit 501 includes a processor that executes part of various processes according to a computer program and a dedicated hardware circuit that executes the rest of the various processes.

[0134] In the above embodiments, an object composed of multiple objects may be integrated, or a single object may be divided into multiple objects. Regardless of whether or not the object is integrated, the object may be configured to achieve the purpose of the present disclosure.

[0135] In the above-described embodiments, while multiple functions are distributed, some or all of these functions can be centralized. Conversely, while multiple functions are centralized, some or all of these functions can be decentralized. Regardless of whether the functions are centralized or decentralized, the configuration is sufficient as long as the objectives of this disclosure can be achieved.

Claims

1. A control device for controlling a wind turbine generator, the wind turbine generator comprising a tower and a nacelle, the control device comprising: a processing circuit configured to control a motor for rotating the nacelle relative to the tower; and a torque information sensor for detecting information related to a torque acting from the nacelle on a gear mechanism that connects the tower and the nacelle so as to be rotatable relative to each other; in, The processing circuit is configured to drive the motor based on a detection value of the torque information sensor.

2. The control device according to claim 1, wherein: The processing circuit is further configured to perform the following processing: acquiring a parameter positively correlated with the torque based on a detection value of the torque information sensor; When the parameter is greater than a first threshold, starting to drive the motor to rotate the nacelle relative to the tower; as well as When the parameter is equal to or smaller than a second threshold value that is smaller than the first threshold value, driving of the motor is stopped.

3. The control device according to claim 2, wherein: The information related to the torque is strain of bolts connecting the nacelle and the gear mechanism.

4. The control device according to claim 3, wherein: The torque information sensor is a first torque information sensor among a plurality of torque information sensors, the motor is a first motor among a plurality of motors, and the bolt is a first bolt among a plurality of bolts. The plurality of motors are configured such that, when the nacelle is coupled to the gear mechanism, the plurality of motors are arranged in a circumferential direction centered on a rotational axis of the nacelle relative to the tower, and each motor is fixed to the nacelle by a respective bolt. Each torque information sensor is set corresponding to each bolt. The processing circuit is configured to acquire the parameter based on a value obtained by statistically processing the detection values ​​of the plurality of torque information sensors.

5. The control device according to claim 2, wherein: A speed detection sensor is further provided, the speed detection sensor being used to detect the speed of wind passing through the nacelle, When a direction along the rotational axis of a blade connected to the nacelle in a plane perpendicular to the rotational axis of the nacelle relative to the tower is defined as a first direction, a direction of wind with respect to the blade in the plane is defined as a second direction, and an acute angle formed by the first direction and the second direction is defined as an offset angle, The processing circuit includes a memory storing correspondence information indicating a correspondence relationship among the information related to the torque, the wind speed, and the deviation angle. The processing circuit is configured to acquire the offset angle as the parameter based on the detection value of the torque information sensor, the detection value of the speed detection sensor, and the correspondence information.

6. The control device according to claim 2, wherein: A speed detection sensor is further provided, the speed detection sensor detecting the speed of wind passing through the nacelle, The processing circuit is further configured to perform the following processing: alternately performing braking of the relative rotation of the nacelle with respect to the tower by driving at least one of an electromagnetic brake that applies a braking force to an output shaft of the motor and a fluid pressure friction brake that applies a braking force to the relative rotation of the nacelle with respect to the tower, and driving the motor; and When the detection value of the speed detection sensor is equal to or less than a predetermined set value, only the electromagnetic brake is driven. When the detection value of the speed detection sensor is greater than the set value, both the electromagnetic brake and the friction brake are driven.

7. A processing circuit for controlling a wind turbine generator, the wind turbine generator comprising a tower and a nacelle, the processing circuit being configured to perform the following processing: acquiring information related to a torque acting from the nacelle on a gear mechanism that couples the tower and the nacelle so as to be rotatable relative to each other; obtaining a parameter positively correlated with the torque based on the information; When the parameter is greater than a first threshold, starting to drive a motor to rotate the nacelle relative to the tower; as well as When the parameter is equal to or smaller than a second threshold value that is smaller than the first threshold value, driving of the motor is stopped.

8. A method for controlling a wind turbine generator system, the wind turbine generator system comprising a tower and a nacelle, the method comprising the following steps: a processing circuit acquiring information related to a torque acting from the nacelle on a gear mechanism that couples the tower and the nacelle in a relatively rotatable manner; The processing circuit obtains a parameter positively correlated with the torque based on the information; When the parameter is greater than a first threshold, the processing circuit starts driving a motor to rotate the nacelle relative to the tower; as well as When the parameter is equal to or less than a second threshold value that is smaller than the first threshold value, the processing circuit stops driving the motor.

9. A non-transitory computer-readable medium storing a program for controlling a wind turbine generator, the wind turbine generator comprising a tower and a nacelle, wherein when the program is executed by a processing circuit, the processing circuit performs the following processing: acquiring information related to a torque acting from the nacelle on a gear mechanism that couples the tower and the nacelle so as to be rotatable relative to each other; obtaining a parameter positively correlated with the torque based on the information; When the parameter is greater than a first threshold, starting to drive a motor to rotate the nacelle relative to the tower; as well as When the parameter is equal to or smaller than a second threshold value that is smaller than the first threshold value, driving of the motor is stopped.

10. A computer program product comprising a program for controlling a wind turbine generator, the wind turbine generator comprising a tower and a nacelle, wherein the program, when executed by a processing circuit, causes the processing circuit to perform the following processing: acquiring information related to a torque acting from the nacelle on a gear mechanism that couples the tower and the nacelle so as to be rotatable relative to each other; obtaining a parameter positively correlated with the torque based on the information; When the parameter is greater than a first threshold, starting to drive a motor to rotate the nacelle relative to the tower; as well as When the parameter is equal to or smaller than a second threshold value that is smaller than the first threshold value, driving of the motor is stopped.

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