# US 2021/0340953 A1 · Pitch varying device, pitch varying method and pitch varying control device for wind turbine blade and wind turbine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0340953 A1 - Document ID: US20210340953A1 - Status: Published application - Kind: A1 - Application number: 17/376,418 - Filed: 2021-07-15 - Published: 2021-11-04 - Earliest claimed: 2017-07-06 - Assignees: Beijing Goldwind Science & Creation Windpower Equipment Co., Ltd. - Applicants: Beijing Goldwind Science & Creation Windpower Equipment Co., Ltd. - Inventors: Yaqi GU; Bing ZHU - Web page: https://patentgrep.com/patent/US20210340953A1 ## CPC - F03D 7/0224: {Adjusting blade pitch} - F03D 7/042: {by means of an electrical or electronic controller} - F03D 80/70: Bearing or lubricating arrangements - F05B 2220/30: in turbines - F05B 2260/406: through hydraulic systems - F05B 2260/76: the adjusting mechanism using auxiliary power sources - F05B 2260/79: Bearing, support or actuation arrangements therefor - F05B 2270/328: Blade pitch angle - F05B 2270/604: hydraulic actuators - Y02E 10/72: Wind turbines with rotation axis in wind direction - F03D: WIND MOTORS - F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A pitch varying device, a pitch varying method and a pitch varying control device for a wind turbine blade and a wind turbine are provided. The blade pitch varying device includes: a disc-type driving structure perpendicular to an axis of a pitch bearing, a track surrounding the axis of the pitch bearing being provided on the disc-type driving structure; a first linear telescopic driving mechanism connected to the track through a first clamping member capable of clamping the track, and the first linear telescopic driving mechanism and the first clamping member being connected through a hinge connection; and a second linear telescopic driving mechanism connected to the track through a second clamping member capable of clamping the track, and the second linear telescopic driving mechanism and the second clamping member being connected through a hinge connection. ## Claims ### Claim 1 A pitch varying device for a blade of a wind turbine, configured to control a pitch angle of the blade rotatably mounted on a hub, and the blade being mounted on the hub through a pitch bearing, and the pitch varying device comprises: a disc-type driving structure fixedly mounted on the blade and being perpendicular to an axis of the pitch bearing, wherein a track surrounding the axis of the pitch bearing is provided on the disc-type driving structure; a first linear telescopic driving mechanism having one end hinged to the hub and another end hinged to a first clamping member; and a second linear telescopic driving mechanism having one end hinged to the hub and another end hinged to a second clamping member; wherein the first linear telescopic driving mechanism is configured to drive the disc-type driving structure in a case that an included angle between a target pitch angle and a present pitch angle is smaller than or equal to a preset threshold; in this case, the first clamping member is configured to clamp the track, and the second clamping member is configured to be disengaged from the track; and the second linear telescopic driving mechanism is configured to drive the disc-type driving structure in a case that the included angle is greater than the preset threshold; in this case, the second clamping member is configured to clamp the track, and the first clamping member is configured to be disengaged from the track. ### Claim 2 (depends on 1) The pitch varying device according to claim 1, wherein the disc-type driving structure is fixedly mounted on an inner ring or an outer ring, that is fixedly connected to the blade, of the pitch bearing. ### Claim 3 (depends on 2) The pitch varying device according to claim 2, wherein the outer ring of the pitch bearing is fixedly connected to the blade, or the inner ring of the pitch bearing is fixedly connected to the blade. ### Claim 4 (depends on 1) The pitch varying device according to claim 1, wherein the disc-type driving structure is a ring-shaped structure, in a radial direction of the ring-shaped structure, the disc-type driving structure comprises a main body portion and an inner circumferential portion from outside to inside; and at least a part of the inner circumferential portion has a thickness greater than that of the main body portion 320, and the least a part of the inner circumferential portion forms the track. ### Claim 5 (depends on 1) The pitch varying device according to claim 1, wherein the first clamping member comprises a first clamping body and a clamp driving mechanism mounted at the first clamping body; and the clamp driving mechanism comprises a piston configured to extend toward the track or retract. ### Claim 6 (depends on 1) The pitch varying device according to claim 1, wherein the first linear telescopic driving mechanism comprises a first telescopic member and a first driving mechanism, the first driving mechanism is configured to drive the first telescopic member to make a telescopic movement, the first driving mechanism is hinged to the hub, and the first telescopic member is hinged to the first clamping member. ### Claim 7 (depends on 6) The pitch varying device according to claim 6, wherein the first driving mechanism is a motor or a hydraulic cylinder. ### Claim 8 (depends on 1) The pitch varying device according to claim 1, wherein the second linear telescopic driving mechanism comprises a second telescopic member and a second driving mechanism, the second driving mechanism is configured to drive the second telescopic member to make a telescopic movement, the second driving mechanism is hinged to the hub, and the second telescopic member is hinged to the second clamping member. ### Claim 9 (depends on 8) The pitch varying device according to claim 8, wherein the second driving mechanism is a motor or a hydraulic cylinder. ### Claim 10 (depends on 1) A control method for the pitch varying device according to claim 1, comprising: acquiring the included angle between the target pitch angle and the present pitch angle; comparing the included angle with the preset threshold; and in the case that the included angle is greater than the preset threshold, sending a first control signal and a second reset signal, wherein the first control signal is configured to control the second linear telescopic driving mechanism to drive the disc-type driving structure, to allow the blade to approach the target pitch angle, and the second reset signal is configured to control the first linear telescopic driving mechanism to be reset to an initial position; and in the case that the included angle is smaller than or equal to the preset threshold, sending a second control signal and a first reset signal, wherein the second control signal is configured to control the first linear telescopic driving mechanism to drive the disc-type driving structure, to allow the blade to reach the target pitch angle, and the first reset signal is configured to control the second linear telescopic driving mechanism to be reset to an initial position; and wherein the preset threshold is greater than 0 degrees. ### Claim 11 (depends on 10) The control method according to claim 10, wherein both the second linear telescopic driving mechanism and the first linear telescopic driving mechanism at the initial positions are not perpendicular to the track. ### Claim 12 (depends on 10) The control method according to claim 10, comprising: sending a stop signal when the blade rotates to the target pitch angle, wherein the stop signal is configured to control the two linear telescopic driving mechanisms to stop at the same time, and to control the two clamping members to clamp the track. ### Claim 13 (depends on 10) The control method according to claim 10, wherein the preset threshold ranges from 0.1 to 5 degrees. ### Claim 14 (depends on 1) A pitch varying control device for the pitch varying device according to claim 1, comprising: an acquiring unit configured to acquire the included angle between the target pitch angle and the present pitch angle; a determining unit configured to compare the included angle with the preset threshold; and a signal sending unit; and wherein in the case that the included angle is greater than the preset threshold, the signal sending unit is configured to send a first control signal, and the first control signal is configured to control the second linear telescopic driving mechanism to drive the disc-type driving structure, to allow the blade to approach the target pitch angle; and in the case that the included angle is smaller than or equal to the preset threshold, the signal sending unit is configured to send a second control signal, and the second control signal is configured to control the first linear telescopic driving mechanism to drive the disc-type driving structure, to allow the blade to reach the target pitch angle; and wherein the preset threshold is greater than 0 degrees. ### Claim 15 (depends on 14) The pitch varying control device according to claim 14, wherein in the case that the included angle is smaller than or equal to the preset threshold, the signal sending unit is further configured to send a first reset signal, and the first reset signal is configured to control the second linear telescopic driving mechanism to be reset to an initial position; and in the case that the included angle is greater than the preset threshold, the signal sending unit is further configured to send a second reset signal, and the second reset signal is configured to control the first linear telescopic driving mechanism to be reset to an initial position. ### Claim 16 (depends on 15) The pitch varying control device according to claim 15, wherein both the second linear telescopic driving mechanism and the first linear telescopic driving mechanism at the initial positions are not perpendicular to the track. ### Claim 17 (depends on 14) The pitch varying control device according to claim 14, wherein the signal sending unit is further configured to send a stop signal when the blade rotates to the target pitch angle, and the stop signal is configured to control the two linear telescopic driving mechanisms to stop at the same time, and to control the two clamping members to clamp the track. ### Claim 18 (depends on 14) The pitch varying control device according to claim 14, wherein the pitch varying control device is embedded in a main controller and/or a pitch varying controller. ### Claim 19 (depends on 14) A wind turbine, comprising the pitch varying control device according to claim 14.