# US 2018/0320664 A1 · Wind turbine variable-pitch control method and device

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- Number: US 2018/0320664 A1
- Document ID: US20180320664A1
- Status: Published application
- Kind: A1
- Application number: 15/773,060
- Filed: 2017-05-18
- Published: 2018-11-08
- Earliest claimed: 2016-08-02
- Assignees: Beijing Goldwind Science & Creation Windpower Equi Pment Co., Ltd.
- Applicants: Beijing Goldwind Science & Creation Windpower Equipment Co., Ltd.
- Inventors: Jie ZHOU; Hao TANG; Qingtian WANG
- Web page: https://patentgrep.com/patent/US20180320664A1

## CPC

- F03D 7/042: {by means of an electrical or electronic controller}
- F03D 7/0224: {Adjusting blade pitch}
- F03D 7/0292: {to reduce fatigue}
- F05B 2260/74: by turning around an axis perpendicular the rotor centre line
- F05B 2270/1095: by limiting mechanical stresses
- F05B 2270/32: Wind speeds
- F05B 2270/327: Rotor or generator speeds
- F05B 2270/328: Blade pitch angle
- 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 method and a device for use in variable-pitch control of a wind turbine, in said method: if a current wind speed is continuously maintained at a small wind speed, then periodically detecting whether a maintained duration of a current pitch angle of a wind turbine reaches a preset duration; once the preset duration is reached, switching a current minimum pitch angle to another minimum pitch angle.

## Claims

### Claim 1

A pitch control method for a wind turbine, comprising:
setting a plurality of minimum pitch angles; and
switching periodically among the plurality of minimum pitch angles according to a first preset duration;
wherein switching periodically among the plurality of minimum pitch angles according to the first preset duration comprises:
determining whether a maintaining duration of a current minimum pitch angle reaches a preset duration, and switching the current minimum pitch angle to another minimum pitch angle of the plurality of the minimum pitch angles in a case that the maintaining duration reaches the preset duration.

### Claim 2 (depends on 1)

The control method according to claim 1, wherein, before the switching periodically among the plurality of minimum pitch angles according to a first preset duration, the method further comprises:
acquiring periodically an operating parameter of the wind turbine according to a second preset duration, and determining whether the operating parameter of the wind turbine is less than a preset threshold; and
performing the switching periodically among the plurality of minimum pitch angles according to a first preset duration, in a case that the operating parameter of the wind turbine is less than the preset threshold.

### Claim 3 (depends on 2)

The control method according to claim 2, further comprising:
switching, in a case that the operating parameter of the wind turbine is greater than or equal to the preset threshold, the current minimum pitch angle to a default minimum pitch angle after a third preset duration, wherein the default minimum pitch angle is less than a minimum value of the plurality of minimum pitch angles.

### Claim 4 (depends on 1)

The control method according to claim 1, wherein the operating parameter comprises:
a wind speed, a turbulence intensity, a rotational speed or a power.

### Claim 5 (depends on 1)

The control method according to claim 1, further comprising:
determining an optimal gain, wherein the optimal gain corresponds to a minimum pitch angle reached after the switching; and
regulating torque of the wind turbine to be torque corresponding to the optimal gain.

### Claim 6

A pitch control device for a wind turbine, comprising:
a minimum pitch angle setting module, configured to set a plurality of minimum pitch angles; and
a minimum pitch angle switching module, configured to switch periodically among the plurality of minimum pitch angles according to a first preset duration;
wherein switching periodically among the plurality of minimum pitch angles according to the first preset duration comprises:
determining whether a maintaining duration of a current minimum pitch angle reaches a preset duration, and switching the current minimum pitch angle to another minimum pitch angle of the plurality of the minimum pitch angles in a case that the maintaining duration reaches the preset duration.

### Claim 7 (depends on 6)

The control device according to claim 6, further comprising:
a wind turbine operating parameter determination module, configured to acquire periodically an operating parameter of the wind turbine according to a second preset duration, and determine whether the operating parameter of the wind turbine is less than a preset threshold; wherein the minimum pitch angle switching module is triggered in a case that the operating parameter of the wind turbine is less than the preset threshold.

### Claim 8 (depends on 7)

The control device according to claim 7, further comprising:
a minimum pitch angle restoring module, configured to switch, in a case that the operating parameter of the wind turbine is greater than or equal to the preset threshold, the current minimum pitch angle to a default minimum pitch angle after a third preset duration, wherein the default minimum pitch angle is less than a minimum value of the plurality of minimum pitch angles.

### Claim 9 (depends on 6)

The control device according to claim 6, wherein the operating parameter acquired by the wind turbine operating parameter determination module comprises:
a wind speed, a turbulence intensity, a rotational speed or a power.

### Claim 10 (depends on 6)

The control device according to claim 6, further comprising:
an optimal gain determination module, configured to determine an optimal gain, wherein the optimal gain corresponds to a minimum pitch angle reached after the switching; and
a torque regulating module, configured to regulate torque of the wind turbine to be torque corresponding to the optimal gain.

### Claim 11 (depends on 1)

A pitch control device for a wind turbine, comprising:
a memory, configured to store instructions for performing the method according to claim 1; and
a processor, configured to read and execute the instructions in the memory.

### Claim 12 (depends on 2)

The control method according to any one of claim 2, wherein the operating parameter comprises:
a wind speed, a turbulence intensity, a rotational speed or a power.

### Claim 13 (depends on 3)

The control method according to any one of claim 3, wherein the operating parameter comprises:
a wind speed, a turbulence intensity, a rotational speed or a power.

### Claim 14 (depends on 3)

The control method according to claim 3, further comprising:
determining an optimal gain, wherein the optimal gain corresponds to a minimum pitch angle reached after the switching; and
regulating torque of the wind turbine to be torque corresponding to the optimal gain.

### Claim 15 (depends on 7)

The control device according to any one of claim 7, wherein the operating parameter acquired by the wind turbine operating parameter determination module comprises:
a wind speed, a turbulence intensity, a rotational speed or a power.

### Claim 16 (depends on 8)

The control device according to any one of claim 8, wherein the operating parameter acquired by the wind turbine operating parameter determination module comprises:
a wind speed, a turbulence intensity, a rotational speed or a power.

### Claim 17 (depends on 8)

The control device according to claim 8, further comprising:
an optimal gain determination module, configured to determine an optimal gain, wherein the optimal gain corresponds to a minimum pitch angle reached after the switching; and
a torque regulating module, configured to regulate torque of the wind turbine to be torque corresponding to the optimal gain.