Wind power generation system control device, wind power generation system processing circuit, wind power generation system control method and wind power generation system control program

Abstract

To enhance power generation efficiency of a wind power generation system.SOLUTION: A processing circuit performs the processes: acquiring information about torque applied from a nacelle to a gear mechanism which enables a tower and the nacelle to relatively rotate and acquiring torque parameter T which positively correlates with the torque based on the information (Steps S100 and S130); when the torque parameter T becomes equal to or greater than a first threshold (Yes in Step S110), driving a motor to rotate the nacelle relative to the tower (Step S120) until the torque parameter T drops to or below a second threshold (Yes in Step S140).SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a control device for a wind turbine generator, a processing circuit for a wind turbine generator, a control method for a wind turbine generator, and a control program for a wind turbine generator. [Background technology]

[0002] The wind turbine generator disclosed in Patent Document 1 includes a tower, a nacelle, a hub, multiple blades, and a wind vane. The nacelle is connected to the top end of the tower. The nacelle is rotatable around a yaw axis. The yaw axis coincides with the central axis of the tower. The nacelle houses a generator. The hub is connected to the input shaft of the generator. The hub is rotatable around a roll axis that is perpendicular to the yaw axis. The multiple blades are connected to the hub. The multiple blades rotate integrally with the hub. The wind vane is attached to the nacelle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-93900 Summary of the Invention [Problem to be solved by the invention]

[0004] In a wind turbine generator such as that described in Patent Document 1, power generation efficiency is high when the wind direction relative to the blades and the extension direction of the roll axis are approximately aligned. Taking this into consideration, it is preferable to adjust the rotational position of the nacelle around the yaw axis so that the wind direction relative to the blades and the extension direction of the roll axis are aligned. When adjusting the rotational position of the nacelle in this manner, it is possible to use the measurement results of a wind vane. However, the wind vane is located downwind of the blades. Therefore, the wind reaching the wind vane may be disturbed or change direction as it passes over the blades. Therefore, the measurement results of the wind vane do not necessarily accurately reflect the actual wind direction experienced by the blades. [Means for solving the problem]

[0005] A control device for a wind power generation device to solve the above problem includes a processing circuit that controls a motor that rotates a nacelle relative to the tower of the wind power generation device, and a sensor that detects information regarding the torque acting from the nacelle on a gear mechanism that connects the tower and the nacelle so that they can rotate relative to each other, and the processing circuit drives the motor based on the detection value of the sensor.

[0006] A control device for a wind power generation device that solves the above problem includes a processing circuit that controls a motor that rotates a nacelle relative to the tower of the wind power generation device, and a sensor that detects information related to the torque acting from the nacelle on a gear mechanism that connects the tower and the nacelle so that they can rotate relative to each other, and the processing circuit executes an acquisition process that acquires a parameter that is positively correlated with the torque based on the detection value of the sensor, and a drive process that, when the parameter becomes equal to or greater than a predetermined first threshold, drives the motor to rotate the nacelle relative to the tower until the parameter becomes equal to or less than a predetermined second threshold that is smaller than the first threshold.

[0007] The torque acting on the gear mechanism from the nacelle reflects the misalignment between the direction of the wind blowing on the blades connected to the nacelle and the central axis of rotation of the blades. By rotating the nacelle based on this torque, each of the above control devices can reduce this misalignment by aligning it with the direction of the wind blowing on the blades. This increases the efficiency of power generation by the wind turbine generator.

[0008] In the control device for a wind turbine generator, the sensor may detect strain on a bolt that connects the nacelle to the gear mechanism as the information related to the torque. In a control device for a wind power generation device, the sensors are provided corresponding to each of the bolts for each of the motors that are arranged circumferentially around the central axis of rotation of the nacelle relative to the tower and that secure the motors to the nacelle, and the processing circuit may acquire the parameters in the acquisition process based on values ​​obtained by statistically processing the detection values ​​of the multiple sensors.

[0009] In a control device for a wind power generation device, when the sensor is defined as a first sensor, a second sensor is provided that detects the speed of wind passing through the nacelle, and when a radial direction centered on the central axis of rotation of the nacelle relative to the tower, a direction along the central axis of rotation of the blades connected to the nacelle is defined as a first direction, a direction of the wind relative to the blades is defined as a second direction, and an acute angle formed by the first direction and the second direction is defined as a deviation angle, the processing circuit may store information related to the torque and correspondence information that represents a correspondence relationship between the wind speed and the deviation angle, and in the acquisition process, the deviation angle may be acquired as the parameter based on the detection value detected by the first sensor, the detection value detected by the second sensor, and the correspondence information.

[0010] In a control device for a wind power generation device, when the sensor is defined as a first sensor, a second sensor is provided that detects the speed of wind passing through the nacelle, and the processing circuit controls, in addition to the motor, an electromagnetic brake that applies a braking force to the 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 alternates between a braking process that brakes the relative rotation of the nacelle with respect to the tower by driving at least one of the electromagnetic brake and the friction brake, and the driving process, and in the braking process, if the detection value of the second sensor is equal to or less than a predetermined set value, only the electromagnetic brake is driven, and if the detection value of the second sensor is greater than the set value, both the electromagnetic brake and the friction brake are driven.

[0011] A processing circuit for a wind power generation device that solves the above problem controls a motor that rotates a nacelle relative to the tower of the wind power generation device, and performs an acquisition process that acquires information about the torque acting from the nacelle on a gear mechanism that connects the tower and the nacelle so that they can rotate relative to each other, and acquires a parameter that is positively correlated to the torque based on the information, and a drive process that, when the parameter becomes equal to or greater than a predetermined first threshold, drives the motor to rotate the nacelle relative to the tower until the parameter becomes equal to or less than a predetermined second threshold that is smaller than the first threshold.

[0012] A control method for a wind turbine generator that solves the above problem includes having a processing circuit, which controls a motor that rotates a nacelle relative to the tower of the wind turbine generator, perform an acquisition process that acquires information about the torque acting from the nacelle on a gear mechanism that connects the tower and the nacelle so that they can rotate relative to each other, and acquires a parameter that is positively correlated to the torque based on the information, and a drive process that, when the parameter becomes equal to or greater than a predetermined first threshold, drives the motor to rotate the nacelle relative to the tower until the parameter becomes equal to or less than a predetermined second threshold that is smaller than the first threshold.

[0013] A control program for a wind turbine generator that solves the above problem causes a processing circuit, whose control object is a motor that rotates a nacelle relative to the tower of the wind turbine generator, to perform an acquisition process that acquires information about the torque acting from the nacelle on a gear mechanism that connects the tower and the nacelle so that they can rotate relative to each other, and acquires a parameter that is positively correlated to the torque based on the information, and a drive process that, when the parameter becomes equal to or greater than a predetermined first threshold, drives the motor to rotate the nacelle relative to the tower until the parameter becomes equal to or less than a predetermined second threshold that is smaller than the first threshold.

[0014] The torque acting on the gear mechanism from the nacelle reflects the misalignment between the direction of the wind blowing on the blades connected to the nacelle and the central axis of rotation of the blades. The processing circuit, control method, and control program described above can reduce this misalignment by rotating the nacelle based on this torque, thereby matching the direction of the wind blowing on the blades. This increases the efficiency of power generation by the wind turbine generator. [Effects of the Invention]

[0015] The above technical concept can increase the efficiency of power generation by the wind power generation device. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view showing the appearance of a wind turbine generator. [Figure 2] FIG. 2 is a top view schematically illustrating the wind turbine generator. [Figure 3] FIG. 3 is a cross-sectional view that schematically shows a part of the wind turbine generator. [Figure 4] FIG. 4 is a cross-sectional view that schematically shows a part of the wind turbine generator. [Figure 5] FIG. 5 is a schematic diagram of the control device. [Figure 6] FIG. 6 is a graph showing the amount of power generated by the generator in relation to the passing wind speed. [Figure 7] FIG. 7 is a flowchart showing the procedure of the braking control. [Figure 8] FIG. 8 is a flowchart showing the processing procedure of the drive control. [Figure 9] FIG. 9 is a graph showing an example of the correspondence relationship between the load torque and the bolt strain. [Figure 10] FIG. 10 is a graph showing an example of the correspondence between the deviation angle, the bolt strain, and the passing wind speed. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of a control device for a wind turbine generator, a processing circuit for a wind turbine generator, a control method for a wind turbine generator, and a control program for a wind turbine generator will be described with reference to the drawings. <Overall structure> As shown in Fig. 1, the wind turbine generator 100 includes a tower 110, a ring gear 210, and a nacelle 160. As shown in Fig. 2, the wind turbine generator 100 also includes a transmission shaft 130, a hub 140, and a plurality of blades 150.

[0018] As shown in FIG. 1, the tower 110 is cylindrical. The tower 110 extends upward from the ground or sea. The interior of the tower 110 is hollow. Power cables for transmitting electricity are laid inside the tower 110. Hereinafter, the central axis of the tower 110 will be referred to as the yaw axis Y. The yaw axis Y extends upward.

[0019] The ring gear 210 is located above the tower 110. Note that the ring gear 210 is exaggerated in size in FIG. 1. As shown in FIG. 2, the ring gear 210 is annular. The central axis of the ring gear 210 substantially coincides with the yaw axis Y. As shown in FIG. 3, a plurality of teeth 212 are present on the outer peripheral surface of the ring gear 210. The plurality of teeth 212 are arranged at equal intervals in the circumferential direction around the central axis of the ring gear 210. The outer diameter of the ring gear 210 substantially coincides with the outer diameter of the top wall 112 of the tower 110. The ring gear 210 is fixed to the top wall 112 of the tower 110.

[0020] As shown in FIG. 1, the nacelle 160 is located above the tower 110 and thus above the ring gear 210. The nacelle 160 has a rectangular parallelepiped outer shape. As shown in FIG. 2, when the wind turbine generator 100 is viewed from above in a plan view, the outer edge dimensions of the nacelle 160 are larger than those of the tower 110 and the ring gear 210. In this plan view, the ring gear 210 is located within an area surrounded by the outer edge of the nacelle 160. The nacelle 160 is hollow. The nacelle 160 houses the generator 170 and other components. The arrangement, shape, and size of each component shown in FIG. 2, including the generator 170, are shown for convenience of understanding and do not necessarily correspond to the actual components.

[0021] As shown in Fig. 3, 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 inward from the ring gear 210 in the radial direction centered on the yaw axis Y faces the upper wall 112 of the tower 110. 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. Supported by this support mechanism 90, the nacelle 160 is rotatable relative to the tower 110 and the ring gear 210, with the yaw axis Y as the central axis of rotation.

[0022] As shown in FIG. 2, the transmission shaft 130 extends from the inside to the outside of the nacelle 160. The central axis of the transmission shaft 130 is perpendicular to the yaw axis Y. Hereinafter, the central axis of the transmission shaft 130 will be referred to as the roll axis R. The transmission shaft 130 is rotatable around the roll axis R as the central axis of rotation. A portion of the transmission shaft 130 located inside the nacelle 160 is connected to the generator 170 via a gearbox (not shown). The generator 170 converts the rotation transmitted from the gearbox into electric power.

[0023] The hub 140 is connected to a portion of the transmission shaft 130 that is located outside the nacelle 160. The hub 140 rotates together with the transmission shaft 130. As shown in Fig. 1, the multiple blades 150 are connected to the hub 140. Therefore, the multiple blades 150 are connected 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 multiple blades 150 are arranged at equal intervals in the circumferential direction centered on the roll axis R. The multiple blades 150 are rotatable together with the hub 140 with the roll axis R as the central axis of rotation.

[0024] <Drive unit> As shown in FIG. 2, the wind turbine generator 100 is equipped with four drive units 50. The four drive units 50 are positioned outward from the ring gear 210 in the radial direction centered on the yaw axis Y. The four drive units 50 are arranged at equal intervals in the circumferential direction centered on the yaw axis Y. As will be explained later, the four drive units 50 are fixed to the nacelle 160. The configuration of each drive unit 50 and the manner of fixing it to the nacelle 160 are the same. Therefore, the following will explain the details using one drive unit 50 shown in FIG. 4 as an example. Note that, as shown in FIG. 4, the wind turbine generator 100 is equipped with a battery 330 and an inverter 69 for each drive unit 50 as components related to the drive units 50.

[0025] As shown in FIG. 4, the drive device 50 includes a motor 60, a reducer 70, and a drive shaft 80. The motor 60 is an electric motor. The motor 60 includes a first case 62, a stator 64, a rotor 66, and an output shaft 68. The first case 62 is located inside the nacelle 160. The first case 62 is located near the bottom wall 162 of the nacelle 160. The first case 62 is cylindrical. The central axis J of the first case 62 is approximately parallel to the yaw axis Y. The stator 64 is located inside the first case 62. The stator 64 is fixed to the first case 62. The stator 64 is cylindrical. Although not shown, a coil is wound around the stator 64. The coil is 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 substantially coincides with the central axis J of the first case 62. In this embodiment, components that are coaxial with the central axis J of the first case 62 are uniformly designated by the symbol J. The output shaft 68 rotates around its own central axis J. Most of the output shaft 68 is located inside the first case 62. Both ends of the output shaft 68 protrude outside the first case 62. A bearing G1 is interposed between a portion of the output shaft 68 that is located toward the end of the first case 62 in the direction along the central axis J and the inner surface of the first case 62. The bearing G1 rotatably supports the output shaft 68.

[0026] The reducer 70 is located between the first case 62 and the bottom wall 162 of the nacelle 160. The reducer 70 includes a second case 72 and a reduction mechanism 74. The second case 72 includes a case main body 72A and a flange 72B. The case main body 72A is cylindrical. The central axis J of the case main body 72A substantially coincides with the central axis J of the first case 62. The case main body 72A is fixed to the first case 62. The flange 72B is located at a lower end of the second case 72. The flange 72B protrudes from the outer peripheral surface of the second case 72. The flange 72B extends around the entire circumference of the case main body 72A. The lower surface of the flange 72B faces the bottom wall 162 of the nacelle 160. The flange 72B is fixed to the bottom wall 162 of the nacelle 160. This fixing structure will be described later.

[0027] The reduction mechanism 74 is located inside the case main body 72A. The reduction mechanism 74 is connected to the output shaft 68 of the motor 60. The torque of the output shaft 68 of the motor 60 is input to the reduction mechanism 74. The reduction mechanism 74 amplifies the torque of the output shaft 68 of the motor 60 at a predetermined ratio and outputs the amplified torque to the drive shaft 80. The reduction mechanism 74 may be, for example, an eccentric oscillating gear type or a planetary gear type. Any type of reduction mechanism 74 may be used as long as it is configured to amplify and output the torque from the motor 60.

[0028] The drive shaft 80 is connected to the reduction gear mechanism 74. The drive shaft 80 protrudes from the inside to the outside of the case body 72A. The central axis J of the drive shaft 80 substantially coincides with the central axis J of the output shaft 68 of the motor 60. A bearing G2 is interposed between the portion of the drive shaft 80 located inside the case body 72A and the inner surface of the case body 72A. The bearing G2 rotatably supports the drive shaft 80. The drive shaft 80 rotates around its own central axis J. The portion of the drive shaft 80 protruding outside the case body 72A passes through a through-hole 162A provided in the bottom wall 162 of the nacelle 160. The end of the portion of the drive shaft 80 protruding outside the case 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.

[0029] The structure for fixing the second case 72 to the nacelle 160 will now be described. The second case 72 is fixed to the bottom wall 162 of the nacelle 160 by a plurality of fasteners 30. Figure 4 shows two of the multiple fasteners 30 as representatives. The multiple fasteners 30 are located on the flange 72B. The multiple fasteners 30 are arranged at equal intervals in the circumferential direction around the central axis J of the case main body 72A. Each fastener 30 has the same configuration and function. Therefore, the following will describe the details using one fastener 30 as an example.

[0030] The fastener 30 is composed of a bolt 32 and a nut 34. The bolt 32 penetrates the flange 72B and the bottom wall 162 of the nacelle 160. The head 32A of the bolt 32 is located on the upper surface of the flange 72B. The end of the bolt 32 opposite the head 32A protrudes downward from the bottom wall 162 of the nacelle 160. The nut 34 is attached to the end of the bolt 32 opposite the head 32A. As a result, the flange 72B and the bottom wall 162 of the nacelle 160 are fixed together.

[0031] Here, as described above, the second case 72 is fixed to the first case 62. In other words, the second case 72 is integral with the first case 62. Since the second case 72 is fixed to the nacelle 160 by the bolts 32, the motor 60 including the first case 62 is also fixed to the nacelle 160 by the bolts 32. Such bolts 32 for fixing the motor 60 to the nacelle 160 are provided for each motor 60, and therefore for each drive unit 50.

[0032] <Pinion gear> As shown in Fig. 2, the wind turbine generator 100 has a plurality of pinion gears 220. A pinion gear 220 is provided for each drive unit 50. The pinion gears 220 are attached to the drive units 50 in the same manner. Therefore, the following will be described in detail using one pinion gear 220 shown in Fig. 4 as an example.

[0033] As shown in FIG. 4, the pinion gear 220 is attached to the end of the portion of the drive shaft 80 that protrudes outside the case main body 72A. The pinion gear 220 is cylindrical. The drive shaft 80 is inserted into a central hole of the pinion gear 220. The central axis J of the pinion gear 220 approximately coincides with the central axis J of the drive shaft 80. The pinion gear 220 rotates integrally with the drive shaft 80. The outer peripheral surface of the pinion gear 220 has a plurality of teeth 222. The plurality of teeth 222 are arranged at equal intervals in the circumferential direction about the central axis J of the pinion gear 220. The outer peripheral surface of the pinion gear 220 faces the outer peripheral surface of the ring gear 210. The teeth 222 of the pinion gear 220 mesh with the teeth 212 of the ring gear 210. Note that FIG. 4 shows only a portion of the plurality of teeth 212 of the ring gear 210. The pinion gear 220 and the ring gear 210 constitute a gear mechanism 200 that connects the tower 110 and the nacelle 160 so as to be capable of relative rotation.

[0034] Here, the flow of power transmission related to the relative rotation of the nacelle 160 with respect to the tower 110 will be described. The motor 60 is capable of outputting 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, the pinion gear 220 rotates as shown by arrow A1 in FIG. 2. At this time, the pinion gear 220 revolves around the periphery of the ring gear 210 while rotating on its own axis. As the pinion gear 220 revolves, the nacelle 160 rotates relative to the tower 110 around the yaw axis Y as the center of rotation as shown by arrow A2 in FIG. 2. In other words, the yaw axis Y is the central axis of rotation of the nacelle 160.

[0035] <Electromagnetic brake> As shown in Fig. 2, the wind turbine generator 100 is equipped with a plurality of electromagnetic brakes 310. The electromagnetic brakes 310 are electromagnetic brakes that utilize electromagnetic force. An electromagnetic brake 310 is provided for each drive unit 50. Each electromagnetic brake 310 has the same configuration. Therefore, the following will be described in detail using one electromagnetic brake 310 shown in Fig. 4 as an example.

[0036] As shown in FIG. 4 , the electromagnetic brake 310 is located on the opposite side of the motor 60 from the reducer 70. The electromagnetic brake 310 includes a third case 312, a contact plate 314, a movable plate 316, an electromagnet 320, and a relay 325. The third case 312 is cylindrical. The central axis J of the third case 312 substantially coincides with the central axis J of the first case 62 of the motor 60. One upper end of the third case 312 in the direction along the central axis J is closed. The lower end of the third case 312 is fixed to the first case 62. A portion of the output shaft 68 of the motor 60 is located inside the third case 312.

[0037] The contact plate 314, the movable plate 316, and the electromagnet 320 are located inside the third case 312. The contact plate 314 is located closer to the first case 62 in the direction along the central axis J of the third case 312. The contact plate 314 is disk-shaped. The output shaft 68 of the motor 60 passes through the vicinity of the center of the contact plate 314. The contact plate 314 rotates integrally with the output shaft 68.

[0038] The electromagnet 320 is located on the opposite side of the contact plate 314 from the first case 62. Although detailed illustration is omitted, the electromagnet 320 includes an electromagnet body, a coil, and a spring. The electromagnet body is fixed to the third case 312. The coil and spring are built into the electromagnet body.

[0039] The movable plate 316 is located between the contact plate 314 and the electromagnet 320. The movable plate 316 is disk-shaped. A hole is formed in the center of the movable plate 316. The diameter of this hole is larger than the diameter of the output shaft 68 of the motor 60. The output shaft 68 is inserted into this hole. The movable plate 316 is movable in a direction along the central axis J of the output shaft 68.

[0040] The relay 325 is located midway along a power line 329 connecting the coil of the electromagnet 320 and the battery 330. The on / off state of the relay 325 switches between energizing and de-energizing the coil of the electromagnet 320. The electromagnet 320 changes the position of the movable plate 316 depending on whether or not the coil is energized. When the coil is not energized, the electromagnet 320 moves the movable plate 316 away from the electromagnet body by the elastic force of the spring. At this time, the spring presses the movable plate 316 against the contact plate 314. Accordingly, a braking force that brakes the rotation of the output shaft 68 is applied to the contact plate 314 and, ultimately, to the output shaft 68 of the motor 60. In other words, the movable plate 316 applies a braking force to the output shaft 68. On the other hand, when the coil is energized, the electromagnet 320 pulls the movable plate 316 toward the electromagnet body against the elastic force of the spring. Accordingly, the movable plate 316 is positioned at a position away from the 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.

[0041] <Friction brake> 3, the wind turbine generator 100 is equipped with a hydraulic friction brake 350. The friction brake 350 is a so-called disc brake. The friction brake 350 includes an extension wall 370, a connecting member 354, a pair of friction members 356, and a hydraulic pressure supply mechanism 360.

[0042] The extension wall 370 protrudes from the outer surface of the tower 110. The extension wall 370 is located near the top 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.

[0043] The connecting member 354 is fixed to the bottom wall 162 of the nacelle 160. The connecting member 354 holds a pair of friction members 356. The pair of friction members 356 are positioned above and below, sandwiching an extension wall 370 between them. The pair of friction members 356 receive hydraulic pressure from a hydraulic pressure supply mechanism 360. The hydraulic pressure supply mechanism 360 includes a pump, a valve for switching oil paths, and the like. The position of the pair of friction members 356 changes depending on whether hydraulic pressure is supplied. When hydraulic pressure is supplied, the pair of friction members 356 move closer to each other. In this case, the pair of friction members 356 sandwich the extension wall 370. The friction force acting between the pair of friction members 356 and the extension wall 370 at this time serves as a braking force that brakes the relative rotation of the nacelle 160 with respect to the tower 110. In other words, the friction brake 350 applies a braking force to the tower 110 and the nacelle 160 to brake their relative rotation. It can be said that the friction brake 350 applies a braking force to the relative rotation of the nacelle 160 with respect to the tower 110. The pair of friction members 356 move away from each other when no hydraulic pressure is supplied. Accordingly, the pair of friction members 356 are disposed at positions away from the extension wall 370. In this case, the braking force on the relative rotation of the nacelle 160 with respect to the tower 110 is released.

[0044] <Sensor> As shown in Figures 2 and 5, the wind turbine generator 100 is equipped with a plurality of strain sensors 21. Note that Figure 5 shows one of the plurality of strain sensors 21 as a representative. The strain sensor 21 is a first sensor. As shown in Figure 2, a strain sensor 21 is provided for each drive device 50. In other words, a strain sensor 21 is provided for each motor 60. The arrangement and functions of each strain sensor 21 are the same. Therefore, the following will explain the details using one strain sensor 21 shown in Figure 4 as an example.

[0045] Any one of the multiple bolts 32 that secure a given drive unit 50 to the nacelle 160 is referred to as the detection target bolt. As shown in FIG. 4, the strain sensor 21 is located near the detection target bolt. In FIG. 4, the strain sensor 21 is shown on the head 32A of the bolt 32. The strain sensor 21 is fixed to the bottom wall 162 of the nacelle 160 by a holder 95. The strain sensor 21 detects strain H of the detection target bolt. As shown in FIG. 5, the strain sensor 21 repeatedly outputs its detection value to a control unit 500, which will be described later.

[0046] Here, the following can be said about the detection target bolt. As shown in FIG. 4 , the detection target bolt is a bolt that connects the drive unit 50 and the nacelle 160. As described above, the pinion gear 220 is connected to the drive shaft 80 of the drive unit 50. In other words, the detection target bolt connects the drive unit 50, and therefore the pinion gear 220, to the nacelle 160. In other words, the detection target bolt connects the gear mechanism 200, which is made up of the pinion gear 220 and the ring gear 210, to the nacelle 160. A plurality of such detection target bolts are lined up in the circumferential direction around the yaw axis Y, taking into account the positions of the drive units 50. A strain sensor 21 is provided corresponding to each of these plurality of detection target bolts.

[0047] 2 and 5, the wind turbine generator 100 is equipped with a wind speed sensor 22. The wind speed sensor 22 is a second sensor. The second sensor is attached to the upper surface of the nacelle 160. The wind speed sensor 22 detects the speed of wind passing over the upper surface of the nacelle 160 as a passing wind speed V. The passing wind speed V detected by the wind speed sensor 22 reflects the speed of wind passing over the blades 150. The wind speed sensor 22 repeatedly outputs its own detection value to the control unit 500, which will be described later.

[0048] 2 and 5, the wind turbine generator 100 includes a wind direction sensor 23. The wind direction sensor 23 is attached to the upper surface of the nacelle 160. The wind direction sensor 23 detects the direction W of the wind passing over the upper surface of the nacelle 160. The wind direction sensor 23 repeatedly outputs its own detection value to the control unit 500, which will be described later.

[0049] <Control unit> 2 and 5, the wind turbine generator 100 includes a control unit 500. The control unit 500 is located inside the nacelle 160. As shown in FIG. 5, the control unit 500 includes a processing circuit 501. Although not shown, the control unit 500 also includes a communication device for communicating with the outside world wirelessly or via a cable, a communication port for acquiring information from various sensors, and the like. The control unit 500, together with the strain sensor 21, the wind speed sensor 22, and the wind direction sensor 23, constitutes a control device 600.

[0050] The processing circuit 501 includes a CPU 510 and a memory 520. The memory 520 includes three types of storage media: a RAM, a ROM, and an electrically rewritable non-volatile memory. In this embodiment, these three types of storage media are collectively referred to as the memory 520. The memory 520 stores in advance a control program N1 for each type of wind turbine generator 100, in which the processing to be executed by the CPU 510 is described, and various types of reference data N2 that are required for the CPU 510 to execute the control program N1.

[0051] The CPU 510 controls various components 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 brake 350.

[0052] <Basic control> The CPU 510 basically operates constantly except when an operator performs maintenance. The CPU 510 continues to execute basic control while it is operating. The basic control is control related to power generation by the generator 170. In basic control, the CPU 510 repeatedly acquires the latest detected value from the wind speed sensor 22. That is, the CPU 510 repeatedly acquires the latest passing wind speed V. When the power generation condition is satisfied, the CPU 510 controls the generator 170 to operate. As shown in FIG. 6 , the power generation condition is that the passing wind speed V is equal to or greater than a permissible lower limit V1 and equal to or less than a permissible upper limit V2. The permissible lower limit V1 is set in advance in consideration of the minimum wind speed at which the blades 150 can rotate, etc. The permissible upper limit V2 is set in advance in consideration of the load on each device located in the power transmission path from the generator 170 to the blades 150, etc. As shown by the solid line in Figure 6, CPU 510 controls generator 170 so that a constant power generation amount P is basically obtained while generator 170 is operating, except when passing wind speed V is low. Note that memory 520 stores in advance 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 types of reference data N2.

[0053] <Braking control> The CPU 510 repeatedly executes braking control during 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. A series of processes executed by the CPU 510 during the braking control will be described below.

[0054] 7, when CPU 510 starts braking control, it first executes the process of step S300. In step S300, CPU 510 determines whether motor 60 is stopped in connection with driving control, which will be described later. If motor 60 is stopped (step S300: YES), CPU 510 proceeds to the process of step S310.

[0055] In step S310, CPU 510 determines whether the latest passing wind speed V is equal to or less than set value VM. Memory 520 pre-stores set value VM. Set value VM is a type of reference data N2. Set value VM is determined in advance, for example, through experiments or simulations, as the maximum value of passing wind speed V at which nacelle 160 can be held in the current rotational position by electromagnetic brake 310 alone, out of electromagnetic brake 310 and friction brake 350. When making the determination in step S310, CPU 510 first acquires the latest passing wind speed V detected by wind speed sensor 22. In essence, CPU 510 refers to the latest value of passing wind speed V, which is repeatedly acquired in basic control. After acquiring the latest passing wind speed V, CPU 510 compares this passing wind speed V with set value VM. If the latest passing wind speed V is equal to or less than set value VM (step S310: YES), CPU 510 proceeds to step S320.

[0056] In step S320, the CPU 510 activates the electromagnetic brake 310. 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 this embodiment, the CPU 510 turns off the relay 325. After the CPU 510 activates the electromagnetic brake 310, the CPU 510 maintains the activated state and ends the process of step S320. The processing time required for the CPU 510 to perform step S320 is, for example, less than one second. This also applies to steps S330 and S340, which will be described later. Note that with respect to the process of step S320, the CPU 510 may have already activated the electromagnetic brake 310 when the process proceeds to step S320, in relation to the braking control process of the previous cycle. In this case, the CPU 510 maintains the activated state of the electromagnetic brake 310 in step S320. When CPU 510 completes the process of step S320, it temporarily ends the series of processes for braking control. After that, CPU 510 promptly starts the braking control of the next cycle. That is, CPU 510 executes the process of step S300.

[0057] On the other hand, in step S310, if the latest passing wind speed V is greater than the set value VM (step S310: NO), the CPU 510 proceeds to step S330. In this case, the CPU 510 drives both the electromagnetic brake 310 and the friction brake 350. The process for driving the electromagnetic brake 310 is the same as that described in step S320. With regard to the friction brake 350, the CPU 510 controls the hydraulic supply mechanism 360 so that the braking force of the friction brake 350 acts on the tower 110 and the nacelle 160. As in step S320, if both the electromagnetic brake 310 and the friction brake 350 are already being driven when the process proceeds to step S330, the CPU 510 maintains those states. After driving both the electromagnetic brake 310 and the friction brake 350, the CPU 510 ends the process of step S330 while maintaining those states. Then, CPU 510 temporarily ends the series of processes for braking control. After this, CPU 510 promptly starts the next cycle of braking control. That is, CPU 510 executes the process of step S300.

[0058] If the CPU 510 determines in step S300 that the motor 60 is being driven (step S300: NO), the CPU 510 proceeds to step S340. In this case, the CPU 510 deactivates both the electromagnetic brake 310 and the friction brake 350 in step S340. 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 this embodiment, the CPU 510 turns on the relay 325. The CPU 510 also 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 the CPU 510 has deactivated both the electromagnetic brake 310 and the friction brake 350 at the time the process proceeds to step S340, the CPU 510 maintains the deactivated state. After deactivating both the electromagnetic brake 310 and the friction brake 350, the CPU 510 terminates the process of step S340 while maintaining the deactivated state. Then, CPU 510 temporarily ends the series of processes for braking control. After this, CPU 510 promptly starts the next cycle of braking control. That is, CPU 510 executes the process of step S300.

[0059] Regarding the braking control described above, the process in which CPU 510 repeats the process of step S320 to maintain the actuation state of electromagnetic brake 310, and the process in which CPU 510 repeats the process of step S330 to maintain the actuation states of both electromagnetic brake 310 and friction brake 350, constitute braking processes. That is, in the braking process, CPU 510 brakes the relative rotation of nacelle 160 with respect to tower 110 by actuating at least one of electromagnetic brake 310 and friction brake 350. Note that, hereinafter, when electromagnetic brake 310 and friction brake 350 are collectively described, they will be simply referred to as brakes.

[0060] <Drive control> The CPU 510 repeatedly executes drive control while the generator 170 is operating. The braking control is a control for driving the relative rotation of the nacelle 160 with respect to the tower 110. A series of processes executed by the CPU 510 in the braking control will be described below. Note that the CPU 510 stops the supply of electricity to the motor 60 when the generator 170 starts operating. In other words, the motor 60 is stopped when the CPU 510 starts operating the generator 170.

[0061] As shown in FIG. 8, when the CPU 510 starts the drive control, it first executes the process of step S100. In step S100, the CPU 510 acquires a 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 section on operation of the embodiment described later. To acquire the torque parameter T, the CPU 510 first acquires the latest detected value from each of the multiple strain sensors 21. That is, the CPU 510 acquires the latest value of the strain H of the bolt 32 from each of the multiple strain sensors 21. Thereafter, the CPU 510 calculates the average value of the acquired multiple values. The CPU 510 then treats the acquired average value as the torque parameter T. Calculating the average value is an example of statistical processing. After acquiring the torque parameter T, the CPU 510 proceeds to step S110. Note that the process of step S100 is an acquisition process. That is, in the acquisition process, CPU 510 acquires the detection value of strain sensor 21 and acquires torque parameter T based on the detection value.

[0062] In step S110, CPU 510 determines whether torque parameter T acquired in step S100 is equal to or greater than a first threshold value T1. Memory 520 stores first threshold value T1 in advance. First threshold value T1 is a type of reference data N2. The specific value of first threshold value T1 will be described later in the section on operation of an embodiment. If torque parameter T acquired in step S100 is less than first threshold value T1 (step S110: NO), CPU 510 returns to the process of step S100. On the other hand, if torque parameter T is equal to or greater than first threshold value T1 (step S110: YES), CPU 510 proceeds to the process of step S120. Note that in relation to the braking control described above, CPU 510 controls the brake to be in an actuated state during execution of steps S110 and S120.

[0063] In step S120, the CPU 510 starts driving the motor 60 in each drive device 50. That is, the CPU 510 starts energizing each motor 60, thereby starting the rotational driving of the output shaft 68 of each motor 60. Note that, when driving each motor 60, the CPU 510 essentially controls the inverter 69 for each motor 60. When the CPU 510 starts driving each motor 60, the nacelle 160 starts rotating relative to the tower 110. When the CPU 510 starts driving each motor 60, the process proceeds to step S130. Note that, in relation to the braking control described above, the CPU 510 subsequently controls the brakes to a non-driving state until the process of step S150 is completed.

[0064] 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 proceeds to step S140.

[0065] In step S140, CPU 510 determines whether torque parameter T acquired in step S130 is equal to or less than second threshold value T2. Memory 520 stores second threshold value T2 in advance. Second threshold value T2 is a type of reference data N2. Second threshold value T2 is predetermined as a value smaller than first threshold value T1. The specific value of second threshold value T2 will be described later in the section on operation of the embodiment. If torque parameter T acquired in step S130 is greater than second threshold value T2 (step S140: NO), CPU 510 returns to the process of step S130. On the other hand, if torque parameter T acquired in step S130 is equal to or less than second threshold value T2 (step S140: YES), CPU 510 proceeds to the process of step S150.

[0066] In step S150, CPU 510 stops motor 60 of each drive device 50. That is, CPU 510 stops the supply of power to each motor 60, thereby stopping the rotation of output shaft 68 of each motor 60. After this, CPU 510 ends the process of step S150. At the same time, CPU 510 temporarily ends the series of processes related to drive control. After this, CPU 510 promptly starts the drive control of the next cycle. That is, CPU 510 starts the process of step S100. Note that the series of processes from when CPU 510 determines YES in step S110 until it ends step S150 constitutes the drive process.

[0067] Here, the CPU 510 can rotate the output shaft 68 of the motor 60 in both forward and reverse directions. Strictly speaking, the CPU 510 performs the following process regarding the above drive process. 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 even after a while from when the CPU 510 starts driving the motor 60, the CPU 510 reverses the rotation direction of the output shaft 68. Then, as described above, the CPU 510 continues driving the motor 60 until the torque parameter T becomes equal to or less than the second threshold value T2. 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.

[0068] <Embodiment Action 1: Overall Flow of Processing Performed by the CPU> The CPU 510 performs braking control and driving control in association with each other during operation of the generator 170. Below, an overview will be given of the overall flow of processing performed by the CPU 510 regarding the braking control and driving control.

[0069] Assume now that the CPU 510 is not driving the motor 60 (step S300: YES) but is driving the brake (step S320 or step S330). That is, the CPU 510 stops the rotation of the nacelle 160. While the brake is being driven, the CPU 510 monitors the transition of the torque parameter T by repeatedly calculating the torque parameter T (steps S100 and S110: NO). Then, when the torque parameter T becomes equal to or 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 becomes equal to or 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 becomes equal to or less than the second threshold value T2. That is, the CPU 510 executes the drive process. When the torque parameter T becomes equal to or 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 activates the brake to maintain the current rotational position of the nacelle 160 (step S320 or step S330). That is, the CPU 510 executes braking processing. When maintaining the nacelle 160 at the current rotational position, if the passing wind speed V is low (step S310: YES), the CPU 510 activates only the electromagnetic brake 310 (step S320). On the other hand, if the passing wind speed V is high (step S310: NO), the CPU 510 activates both the electromagnetic brake 310 and the friction brake 350 (step S330).

[0070] Now, suppose that the wind direction changes while CPU 510 is holding the rotational position of nacelle 160 with the brake activated. Then, torque parameter T increases for reasons described below. When torque parameter T becomes equal to or greater than first threshold value T1 (step S110: YES), CPU 510 again drives motor 60 and releases the brake. Then, CPU 510 rotates nacelle 160 until torque parameter T becomes equal to or less than second threshold value T2 (step S140: YES). Thereafter, CPU 510 activates the brake to hold nacelle 160 in the position after rotation.

[0071] In this way, CPU 510 alternately repeats the driving process and the braking process during operation of generator 170. At the same time, CPU 510 selects the brake to be used in accordance with passing wind speed V in the braking process.

[0072] <Embodiment Action 2: Detected Value of Strain Sensor> 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. As a premise, as shown in Fig. 2, among the radial directions centered on the yaw axis Y, a direction along the roll axis R and a direction toward the blade 150 from the opposite side of the hub 140 from the nacelle 160 will be referred to as a first direction D1. Furthermore, among the radial directions centered on the yaw axis Y, the direction of the wind relative to the blade 150 will be referred to as a second direction D2. The acute angle formed by the first direction D1 and the second direction D2 will be referred to as a deviation angle DA.

[0073] Now, assume that the CPU 510 is not driving the motor 60 and that the electromagnetic brake 310 is holding the nacelle 160 at a certain rotational position. Under these circumstances, assume that the wind direction changes, increasing the deviation angle DA. If the deviation angle DA is zero, a force acting on the blades 150 as a whole in a direction that coincides with the roll axis R, i.e., a force perpendicular to the blades 150, acts on the blades 150. On the other hand, if the deviation angle DA is large, a force acting on the blades 150 in a direction that intersects the roll axis R, i.e., a force that is not perpendicular to the blades 150, acts on the blades 150. The blades 150 are then pushed by the wind so as to increase the deviation angle DA. In other words, as shown by arrow B in FIG. 2 , the blades 150 are subjected to a force that tends to rotate the blades 150 in a circumferential direction about the yaw axis Y. This force acts on the nacelle 160, which is connected to the blades 150. The nacelle 160 therefore tends to rotate in a circumferential direction about the yaw axis Y. As shown in FIG. 4 , the force acting on the nacelle 160 at this time is transmitted to the second case 72 via the bolt 32 connecting the nacelle 160 and the drive unit 50. If the pinion gear 220 were rotatable at this time, the pinion gear 220 would rotate relative to the ring gear 210 in response to the force from the nacelle 160. However, in reality, the rotation of the output shaft 68 of the motor 60, and therefore the rotation of the pinion gear 220, is braked by the electromagnetic brake 310, so the pinion gear 220 is unable to rotate. As a result, a load is placed on the bolt 32 connecting the nacelle 160, which is attempting to rotate, and the drive unit 50, which is attempting to prevent that rotation. This causes the bolt 32 to become distorted. The strain sensor 21 detects the strain H of the bolt 32. That is, the detection value detected by strain sensor 21 reflects load torque HT, which is the torque acting on pinion gear 220 from nacelle 160 when nacelle 160 is held in a fixed position by electromagnetic brake 310. Therefore, the detection value of strain sensor 21 is information related to load torque HT. At the same time, as shown in Fig. 9, the detection value of strain sensor 21 is positively correlated with load torque HT.9 shows an example of the correspondence between the load torque HT and the strain H of the bolt 32, calculated, for example, by an experiment or a simulation. In view of the relationship between the load torque HT and the detection values ​​of the strain sensors 21 described above, the torque parameter T, which is the average value of the detection values ​​of the multiple strain sensors 21, is positively correlated with the load torque HT.

[0074] Now, taking into consideration the above-described correspondence between the torque parameter T and the deviation angle DA, the processing performed by the CPU 510 in the drive control and braking control will be described again. In the drive control, the CPU 510 drives the motor 60 when the torque parameter T increases, i.e., when the deviation angle DA increases. This causes the CPU 510 to rotate the nacelle 160 relative to the tower 110. Accordingly, the CPU 510 gradually reduces the deviation angle DA toward zero. When the torque parameter T decreases, i.e., when the deviation angle DA decreases, 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 the position where the deviation angle DA is small, the blades 150 can receive the wind substantially head-on. In the braking control, the CPU 510 brakes the rotation of the nacelle 160 at such a position where the blades 150 can receive the wind substantially head-on.

[0075] <Embodiment 3: First Threshold and Second Threshold> The first threshold T1 related to the drive control will be described. The first threshold T1 is predetermined as, for example, the following value. A virtual circle connecting the rotational locus of the outer edge of the blade 150 when the blade 150 rotates around the roll axis R is referred to as the blade circle. The projected area of ​​the blade circle when the blade 150 is viewed from a plane in the first direction D1 described in FIG. 2 is referred to as the first area. The projected area of ​​the blade circle when the blade 150 is viewed from a plane in the second direction D2 described in FIG. 2 is referred to as the second area. The deviation angle DA when the second area is 90% of the first area is referred to as the limit angle. The first threshold T1 is predetermined, for example, through experiments or simulations, as the strain H of the bolt 32 that indicates when the deviation angle DA exceeds the limit angle. In other words, the first threshold T1 is set to a value that allows high power generation efficiency to be maintained. Note that high power generation efficiency means that a higher power generation amount P can be obtained under the same environmental conditions and under the same operating state of the generator 170.

[0076] The second threshold value T2 related to the drive control will be described below. The second threshold value T2 is determined in advance, for example, through an experiment or a simulation, as the strain H of the bolt 32 at which it can be determined that the deviation angle DA is approximately zero.

[0077] <Embodiment 4: Brakes Used in Braking Process> As described above, in the braking process, the CPU 510 changes the brake to be used depending on the passing wind speed V. The reason for this will be explained. As a premise, the braking force of the friction brake 350 is significantly stronger than the braking force of the electromagnetic brake 310. In addition, the friction brake 350 brakes the movement of the nacelle 160 itself. Therefore, if the friction brake 350 is driven when the passing wind speed V is low, the nacelle 160 will not move at all even if the deviation angle DA is large. Therefore, even if the deviation angle DA is large, no strain H will be generated in the bolt 32, and the torque parameter T will remain approximately zero (step S110: NO). In this case, due to the drive control settings, the CPU 510 will not drive the motor 60 and therefore the rotation of the nacelle 160, so the large deviation angle DA will continue. To avoid this situation, the CPU 510 maintains the rotational position of the nacelle 160 by using only the electromagnetic brake 310 when the passing wind speed V is low. If only electromagnetic brake 310 is driven, strain H occurs in bolt 32 in accordance with deviation angle DA. Therefore, CPU 510 can adjust the rotational position of nacelle 160 in accordance with deviation angle DA. Note that, under conditions where passing wind speed V is low, CPU 510 can maintain the rotational position of nacelle 160 using only the braking force of electromagnetic brake 310.

[0078] Now, when the passing wind speed V is high, it becomes difficult to maintain the current rotational position of the nacelle 160 using only the electromagnetic brake 310. Therefore, when the passing wind speed V is high, the CPU 510 maintains the rotational position of the nacelle 160 using both the electromagnetic brake 310 and the friction brake 350. Here, when the passing wind speed V is high, the friction brake 350 alone cannot withstand the force that attempts to rotate the nacelle 160. Therefore, when the passing wind speed V is high, even when both the electromagnetic brake 310 and the friction brake 350 are used, strain H occurs in the bolt 32 in accordance with the deviation angle DA. At the same time, the torque parameter T increases. Therefore, when the passing wind speed V is high, the rotational position of the nacelle 160 can be adjusted in accordance with the deviation angle DA even when both the electromagnetic brake 310 and the friction brake 350 are used.

[0079] <Effects of the embodiment> (1) As described above, when the torque parameter T increases, that is, when the deviation angle DA increases, the CPU 510 rotates the nacelle 160 until the torque parameter T decreases. Therefore, the CPU 510 can quickly decrease the deviation angle DA in accordance with the direction of the wind that the blades 150 receive at each timing.

[0080] Here, it is conceivable to use the detection value of the wind direction sensor 23 to determine the wind deviation angle DA. However, using the detection value of the wind direction sensor 23 has 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 be disturbed or change direction as it passes over the blades 150. As a result, the detection value of the wind direction sensor 23 may differ from the actual wind direction experienced by the blades 150. Therefore, it is difficult to determine the wind deviation angle DA in real time using the detection value of the wind direction sensor 23. To reduce the influence of such instantaneous wind direction fluctuations contained in the detection value of the wind direction sensor 23, it is conceivable to refer to the average value of the detection value of the wind direction sensor 23 over a relatively long predetermined period of time, such as 10 minutes. However, referring to such an average value over a predetermined period of time does not allow for the determination of the instantaneous wind deviation angle DA at each timing. Furthermore, if the rotational position of the nacelle 160 were adjusted at predetermined intervals based on this average value, the wind deviation angle DA would increase over the predetermined period of time, and the power generation amount P would remain low over the predetermined period of time.

[0081] In this regard, the CPU 510 of this embodiment can grasp the load torque HT and therefore the deviation angle DA in real time by using the detection value of the strain sensor 21. Therefore, the CPU 510 can rotate the nacelle 160 to the optimal rotational position for power generation at each timing. The blades 150 can then receive the wind from almost directly ahead at almost all times. In this case, as shown by the solid line in FIG. 6, the power generation amount P under the same passing wind speed V is greater than in the case where the rotational position of the nacelle 160 is adjusted every predetermined time based on the average value of the detection value of the wind direction sensor 23 every predetermined time (the two-dot chain line in FIG. 6). In other words, the configuration of this embodiment improves the efficiency of power generation by the wind turbine generator 100.

[0082] Furthermore, the configuration of this embodiment enables the following in relation to the allowable upper limit V2 related to the power generation conditions. That is, assuming that the rotation of the nacelle 160 is controlled based on the average value of the detection value of the wind direction sensor 23 over a predetermined period of time, the allowable upper limit V2A needs to be set to a value that anticipates that the offset angle DA may increase over the predetermined period of time. That is, when it is anticipated that the power generation amount P of the generator 170 may decrease due to the offset angle DA increasing over the predetermined period of time, the allowable upper limit V2A needs to be set low, taking into account the cost-effectiveness of the power consumption and the load on each device involved in the operation of the generator 170. In this case, the range of the passing wind speed V at which the generator 170 can be operated is narrowed. In this regard, the configuration of this embodiment, which can adjust the rotational position of the nacelle 160 according to the offset angle DA in real time, does not result in a decrease in the power generation amount P at each passing wind speed V, and therefore the allowable upper limit V2 can be set to the maximum allowable value. Accordingly, the range of the passing wind speed V at which the generator 170 can be operated is expanded. Therefore, in the configuration of this embodiment, a larger amount of power generation P can be secured under the same environmental conditions.

[0083] (2) The CPU 510 of this embodiment uses the detection value of the strain sensor 21 as an index of the load torque HT. It is also possible to use, for example, the amount of rotation of the output shaft 68 or the drive shaft 80 of the motor 60 as an index of the load torque HT. However, the amount of rotation of the output shaft 68 or the drive shaft 80 related to the load torque HT is extremely small. Even if one attempts to associate information on such an extremely small amount of rotation with the load torque HT, it is difficult to accurately determine the correspondence between the amount of rotation and the load torque HT. In this regard, it can be said that the detection value of the strain sensor 21 directly reflects the load torque HT. Therefore, the CPU 510 of this embodiment, which uses the detection value of the strain sensor 21 as an index of the load torque HT, can determine the deviation angle DA and rotate the nacelle 160 with the same degree of accuracy as if the load torque HT itself were actually detected.

[0084] (3) In this embodiment, the multiple drive units 50 are disposed at different positions in the circumferential direction around the yaw axis Y. Due to differences in the installation positions of the drive units 50, the magnitude of the load torque HT acting from the nacelle 160 on the gear mechanism 200 may vary slightly depending on the installation position of the drive units 50. Consequently, errors may occur between the detected values ​​of the multiple strain sensors 21. Furthermore, errors may occur between the detected values ​​of the multiple strain sensors 21 due to individual differences between the strain sensors 21. Taking these factors into consideration, the CPU 510 of this embodiment calculates the average value of the detected values ​​of the multiple strain sensors 21 as the torque parameter T. Averaging the detected values ​​of the multiple strain sensors 21 is likely to cancel out the errors described above. The CPU 510 of this embodiment, which uses this average value, can more appropriately adjust the rotational position of the nacelle 160 in order to increase power generation efficiency.

[0085] (4) The CPU 510 of this embodiment changes the brake to be used depending on the magnitude of the passing wind speed V. As a result, as described in the section of action 4 of the above embodiment, the CPU 510 can rotate the nacelle 160 to a position optimal for power generation and hold the nacelle 160 in that rotated position, regardless of the magnitude of the passing wind speed V.

[0086] <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0087] The torque parameter T acquired in the acquisition process is not limited to the example in the above embodiment. The torque parameter T may be any parameter that is positively correlated with the load torque HT. In other words, the torque parameter T may be any parameter that increases as the load torque HT increases. For example, the load torque HT itself may be acquired as the torque parameter T. In this case, information representing the correspondence between the strain H of the bolt 32 and the load torque HT may be stored in advance in the memory 520 as reference data N2. Then, the CPU 510 may acquire the load torque HT corresponding to the detection value of the strain sensor 21 based on this information. When the torque parameter T is changed from the example in the above embodiment, the first threshold value T1 and the second threshold value T2 may be changed in accordance with the changed physical quantity.

[0088] The deviation angle DA may be used as the torque parameter T. In this case, the following aspects may be considered as the processing details of the CPU 510 related to drive control. When the deviation angle DA is used as the torque parameter T, the following correspondence information is stored in advance in the memory 520. The correspondence information is information representing the correspondence relationship between the strain H of the bolt 32, the passing wind speed V, and the deviation angle DA. The correspondence information is a type of reference data N2. As shown in FIG. 10, the correspondence information represents the correspondence relationship between the deviation angle DA and the strain H of the bolt 32 for each passing wind speed V. In the example of FIG. 10, the relationship between the deviation angle DA and the strain H of the bolt 32 is represented for two passing wind speeds V, a first wind speed VX1 and a second wind speed VX2, which are representative of the correspondence relationship for each passing wind speed V. The first wind speed VX1 is greater than the second wind speed VX2. As shown in Fig. 10, for the same passing wind speed V, the larger the deviation angle DA, the larger the strain H of the bolt 32. Also, for the same deviation angle DA, the higher the passing wind speed V, the larger the strain H of the bolt 32. Such correspondence information is created, for example, based on experiments or simulations. Note that the correspondence information may also be one that shows the deviation angle DA in relation to the load torque HT together with the passing wind speed V, instead of the strain H of the bolt 32.

[0089] In the acquisition process of steps S100 and S130 of the drive control shown in FIG. 8, the CPU 510 acquires the deviation angle DA, which is the torque parameter T, as follows. First, the CPU 510 acquires the latest detection value from each of the multiple strain sensors 21. Then, the CPU 510 calculates the average value of the acquired detection values ​​as the average strain. The CPU 510 also acquires the latest detection value from the wind speed sensor 22. Thereafter, the CPU 510 acquires the deviation angle DA corresponding to the average strain and the latest passing wind speed V as the deviation angle DA according to the current situation based on the correspondence information. That is, the CPU 510 acquires the deviation angle DA based on the average strain obtained by statistically processing the detection values ​​of the multiple strain sensors 21. In the drive control, the CPU 510 makes the determinations of steps S110 and S140 based on the torque parameter T acquired in this manner. If the determination in step S110 is YES, then in step S120, CPU 510 drives motor 60. If the determination in step S140 is YES, then CPU 510 stops motor 60 in step S150. As described above, when deviation angle DA is used as torque parameter T, first threshold value T1 and second threshold value T2 are appropriately changed accordingly.

[0090] When the deviation angle DA is used as the torque parameter T, the CPU 510 can drive the motor 60 based on the deviation angle DA itself. Therefore, the CPU 510 can adjust the rotational position of the nacelle 160 more directly to eliminate the deviation angle DA.

[0091] 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 determined as appropriate, taking into consideration the frequency at which the motor 60 is driven and the magnitude of the allowable deviation angle DA. The first threshold value T1 is not limited to a fixed value. In other words, the first threshold value T1 may be variably set depending on, for example, the passing wind speed V.

[0092] The definition of the second threshold T2 is not limited to the example in the above embodiment. The second threshold T2 may be smaller than the first threshold T1. As with the first threshold T1, the second threshold T2 is not limited to a fixed value.

[0093] The method of statistically processing the detection values ​​of the multiple strain sensors 21 is not limited to the example in the above embodiment. For example, the statistical processing may involve extracting the median, minimum, or maximum 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. The statistical processing may be any process that can extract characteristics that can be understood from the detection values ​​of the multiple strain sensors 21.

[0094] It is not necessary to use the detection values ​​of multiple strain sensors 21 when calculating the torque parameter T. That is, 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.

[0095] The first sensor is not limited to the example in the above embodiment. The first sensor may be any sensor that can detect information related to the load torque HT. As in a modified example described below, a current sensor that detects the current value of the motor 60 may be used as the first sensor. When a sensor other than the strain sensor 21 is used as the first sensor, the strain sensor 21 may be eliminated from the wind turbine generator 100. When the first sensor is changed from the example in the above embodiment, the information related to the load torque HT acquired in the acquisition process also changes.

[0096] The configuration of the electromagnetic brake 310 is not limited to the example in the above embodiment. The electromagnetic brake 310 may be configured to apply a braking force to the output shaft 68 of the motor 60 using electromagnetic force. For example, the electromagnetic brake 310 may be configured to apply a braking force to the output shaft 68 when the relay 325 is turned on.

[0097] The configuration of the friction brake 350 is not limited to the example of the above embodiment. The friction brake 350 may be any brake that can apply a braking force to the tower 110 and the nacelle 160 by fluid pressure to brake the relative rotation between them. The fluid pressure is not limited to hydraulic pressure. The fluid pressure may be, for example, gas pressure.

[0098] To maintain the rotational position of the nacelle 160, it is not necessary to change the brake to be used in accordance with the passing wind speed V. For example, if the magnitude of the braking force of the friction brake 350 can be adjusted, it is possible to have the friction brake 350 exert a braking force that is sufficient to generate a load torque HT and, in turn, strain H of the bolts 32 when the passing wind speed V is low. Also, if it is possible to use a spring with a fairly high elastic force in the electromagnetic brake 310 or to increase the electromagnetic force considerably, it is possible to maintain the rotational position of the nacelle 160 solely by the electromagnetic brake 310 when the passing wind speed V is high.

[0099] It is not necessary to use the electromagnetic brake 310 or the friction brake 350 to maintain the rotational position of the nacelle 160. For example, instead of using these brakes to maintain the rotational position of the nacelle 160, the rotational position of the nacelle 160 may be maintained by continuing to energize the motor 60 and applying torque to the output shaft 68 of the motor 60. If such a configuration is adopted, it is also possible to eliminate either or both of the electromagnetic brake 310 and the friction brake 350 from the wind turbine generator 100. Note that, if the motor 60 is continued to be energized to maintain the rotational position of the nacelle 160, the torque acting on the output shaft 68 and, ultimately, the pinion gear 220 can be determined based on the current value flowing through the motor 60. Therefore, a current sensor that detects the current value flowing through the motor 60 may be provided in the wind turbine generator 100, and this current sensor may be used as the first sensor. In this case, the current sensor detects the current value flowing through the motor 60 as information regarding the load torque HT.

[0100] The configuration of the drive unit 50 is not limited to the example of the above embodiment. The drive unit 50 only needs to include the motor 60 that drives the relative rotation of the nacelle 160 with respect to the tower 110. For example, the shape of the case, the fixing structure with respect to the nacelle 160, etc. may be changed from the example of the above embodiment.

[0101] The overall configuration of the wind turbine generator 100 is not limited to the above-described embodiment. For example, the position and number of the drive units 50 may be changed from those in the above-described embodiment. The configuration of the nacelle 160 may be changed from that in the above-described embodiment. 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. In such a configuration, the drive units 50 may be attached to the bottom wall. In this case, the drive units 50 are exposed to the outside of the main body of the nacelle 160. The location of the control unit 500 may be changed from that in the above-described embodiment. The control unit 500 may be located outside the nacelle 160, for example, inside the tower 110. The configuration of the gear mechanism 200 that connects the nacelle 160 and the tower 110 so that they can rotate relative to each other may be different from that in the above-described embodiment. For example, the ring gear 210 may have multiple teeth 212 on its inner circumferential surface rather than its outer circumferential surface. In addition, the drive unit 50 may be disposed inside the ring gear 210 in the radial direction centered on the yaw axis Y. Alternatively, the ring gear 210 may be attached to the nacelle 160, and the drive unit 50 may be attached to the tower 110. The configuration of the gear mechanism 200 is not important as long as the nacelle 160 and the tower 110 can be connected to each other so as to be capable of relative rotation. The wind turbine generator 100 may be provided with a nacelle 160 that is rotatable relative to the tower 110, and a motor 60 that drives this relative rotation. The motor 60 is not limited to being electrically driven.

[0102] The configuration of the control device 600 is not limited to the example of 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 that rotates the nacelle 160 relative to the tower 110. If the processing content of the processing circuit 501 does not include the use of the detection value of the wind speed sensor 22, the wind speed sensor 22 may be eliminated from the control device 600. The same applies to the wind direction sensor 23.

[0103] 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 depending on the passing wind speed V is not essential. Furthermore, if the motor 60 can be appropriately controlled without performing the driving process, the driving process may be eliminated. Furthermore, if the motor 60 can be appropriately controlled without acquiring the torque parameter T, the acquisition process may be eliminated. The processing content of the processing circuit 501 may be any processing that drives the motor 60 that rotates the nacelle 160 relative to the tower 110 based on the detection value of a sensor that detects information about the load torque HT.

[0104] The processing circuit 501 may have any one of the following configurations (a) to (c). (a) The processing circuit 501 includes one or more processors that execute various processes according to a computer program. The processor includes a CPU and memory such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any available medium that can be accessed by a general-purpose or special-purpose computer.

[0105] (b) The processing circuit 501 includes one or more dedicated hardware circuits for executing various processes. Examples of the dedicated hardware circuits include an application specific integrated circuit (ASIC) or an FPGA.

[0106] (c) The processing circuitry 501 includes a processor that executes some of the various processes in accordance with a computer program, and a dedicated hardware circuit that executes the remaining processes among the various processes.

[0107] In the above embodiments, if an object is made up of multiple objects, the multiple objects may be integrated, and conversely, if an object is made up of a single object, it may be divided into multiple objects. Regardless of whether the objects are integrated or not, it is sufficient that the object of the invention can be achieved.

[0108] In the above embodiments, where multiple functions are provided in a distributed manner, some or all of the multiple functions may be provided in a consolidated manner, and conversely, where multiple functions are provided in a consolidated manner, some or all of the multiple functions may be provided in a distributed manner. Regardless of whether the functions are consolidated or distributed, it is sufficient that the configuration is such that the object of the invention can be achieved. [Explanation of symbols]

[0109] N1...Control program 21...Strain sensor 22...Wind speed sensor 32...volts 60...Motor 68...Output shaft 100...Wind power generation equipment 110...Tower 150...Blade 160...Nacelle 200...Gear mechanism 310...Electromagnetic brake 350...Friction brake 501...Processing circuit 600...Control device

Claims

1. a processing circuit that controls a motor that rotates a nacelle relative to a tower of a wind turbine; a sensor for detecting information relating to a torque acting from the nacelle on a gear mechanism that connects the tower and the nacelle so as to be capable of relative rotation; The processing circuit drives the motor based on the detected value of the sensor. Control device for wind power generation equipment.

2. a processing circuit that controls a motor that rotates a nacelle relative to a tower of a wind turbine; a sensor for detecting information relating to a torque acting from the nacelle on a gear mechanism that connects the tower and the nacelle so as to be capable of relative rotation; The processing circuitry an acquisition process of acquiring a parameter positively correlated with the torque based on the detection value of the sensor; a driving process for rotating the nacelle relative to the tower by driving the motor when the parameter becomes equal to or greater than a predetermined first threshold value until the parameter becomes equal to or less than a predetermined second threshold value that is smaller than the first threshold value; Run Control device for wind power generation equipment.

3. The sensor detects strain on a bolt that connects the nacelle to the gear mechanism as information related to the torque. The control device for a wind turbine generator according to claim 2.

4. the sensors are provided corresponding to the bolts for the plurality of motors arranged in a circumferential direction around a central axis of rotation of the nacelle relative to the tower, the bolts being used to fix the motors to the nacelle; In the acquisition process, the processing circuit acquires the parameter based on a value obtained by statistically processing detected values ​​of the plurality of sensors. The control device for a wind turbine generator according to claim 3.

5. When the sensor is a first sensor, a second sensor is provided to detect the speed of wind passing through the nacelle, When a direction along the central axis of rotation of the blades connected to the nacelle among radial directions centered on the central axis of rotation of the nacelle relative to the tower is defined as a first direction, a wind direction relative to the blades is defined as a second direction, and an acute angle formed between the first direction and the second direction is defined as a deviation angle, The processing circuitry Correspondence information representing a correspondence relationship between the information about the torque, the wind speed, and the deviation angle is stored, In the acquisition process, the deviation angle is acquired as the parameter based on the detection value detected by the first sensor, the detection value detected by the second sensor, and the correspondence information. The control device for a wind turbine generator according to claim 2.

6. When the sensor is a first sensor, a second sensor is provided to detect the speed of wind passing through the nacelle, The processing circuitry In addition to the motor, an electromagnetic brake that applies a braking force to the 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 are controlled, a braking process for braking the relative rotation of the nacelle with respect to the tower by activating at least one of the electromagnetic brake and the friction brake; and the driving process are alternately performed, In the braking process, when the detection value of the second sensor is equal to or less than a predetermined set value, only the electromagnetic brake is driven, and when the detection value of the second sensor is greater than the set value, both the electromagnetic brake and the friction brake are driven. The control device for a wind turbine generator according to claim 2.

7. The motor that rotates the nacelle relative to the tower of the wind turbine is the object to be controlled. an acquisition process for acquiring information about a torque acting from the nacelle on a gear mechanism that connects the tower and the nacelle so as to be capable of relative rotation, and acquiring a parameter that is positively correlated with the torque based on the acquired information; a driving process for rotating the nacelle relative to the tower by driving the motor when the parameter becomes equal to or greater than a predetermined first threshold value until the parameter becomes equal to or less than a predetermined second threshold value that is smaller than the first threshold value; Run Processing circuitry for wind power generation equipment.

8. A processing circuit for controlling a motor that rotates a nacelle relative to a tower of a wind turbine generator, an acquisition process for acquiring information about a torque acting from the nacelle on a gear mechanism that connects the tower and the nacelle so as to be capable of relative rotation, and acquiring a parameter that is positively correlated with the torque based on the acquired information; a driving process for rotating the nacelle relative to the tower by driving the motor when the parameter becomes equal to or greater than a predetermined first threshold value until the parameter becomes equal to or less than a predetermined second threshold value that is smaller than the first threshold value; Run A control method for a wind power generating device.

9. A processing circuit for controlling a motor that rotates a nacelle relative to a tower of a wind turbine generator, an acquisition process for acquiring information about a torque acting from the nacelle on a gear mechanism that connects the tower and the nacelle so as to be capable of relative rotation, and acquiring a parameter that is positively correlated with the torque based on the acquired information; a driving process for rotating the nacelle relative to the tower by driving the motor when the parameter becomes equal to or greater than a predetermined first threshold value until the parameter becomes equal to or less than a predetermined second threshold value that is smaller than the first threshold value; Run A control program for wind power generation equipment.

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