# US 2019/0170116 A1 · Control method for a wind turbine

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- Number: US 2019/0170116 A1
- Document ID: US20190170116A1
- Status: Published application
- Kind: A1
- Application number: 16/314,000
- Filed: 2017-06-29
- Published: 2019-06-06
- Earliest claimed: 2016-06-30
- Assignees: Vestas Wind Systems A/S
- Applicants: Vestas Wind Systems A/S
- Inventors: Johnny Nielsen
- Web page: https://patentgrep.com/patent/US20190170116A1

## CPC

- F03D 7/0204: {for orientation in relation to wind direction}
- F03D 17/00: Monitoring or testing of wind motors, e.g. diagnostics (testing during commissioning of wind motors F03D13/30)
- F05B 2270/321: Wind directions
- F05B 2270/329: Azimuth or yaw angle
- F05B 2270/802: Calibration thereof
- 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 wind turbine includes a wind direction sensor, a yawing system, and a control system for yawing the wind turbine rotor relative to the wind. The control system measures a wind direction parameter by the wind direction sensor Over time a group of data sets is obtained and a wind direction offset is determined from the group of data sets which is used to adjust the wind direction parameter. The adjusted wind direction parameter is then used in the controlling of the wind turbine.

## Claims

### Claim 1

A method of controlling a wind turbine, the wind turbine comprising a wind direction sensor for measuring a wind direction parameter indicative of the wind direction relative to the wind turbine, a yawing system, and a control system for yawing the wind turbine rotor relative to the wind, the method comprising:
measuring a first wind direction parameter by the wind direction sensor;
performing a yaw event comprising the steps of determining a control parameter of the wind turbine as a function of the wind direction parameter, wherein the control parameter comprises a yawing parameter for the wind turbine, and controlling the wind turbine according to the control parameter, wherein the controlling comprises yawing the wind turbine according to the yawing parameter;
measuring a wind direction parameter by the wind direction sensor after said yawing event;
determining a data set comprising the first wind direction parameter, a wind direction sensor angle determined as a difference in the measured wind direction parameter before and after the yawing event, and a yaw angle indicative of the yawing performed during the yawing event;
obtaining over time a group of data sets;
determining a wind direction offset from the group of data sets;
adjusting the wind direction parameter as a function of the wind direction offset, and
applying the adjusted wind direction parameter in the controlling of the wind turbine.

### Claim 2 (depends on 1)

A method of controlling according to claim 1, further comprising determining for each data set a difference between the yaw angle and the wind direction sensor angle and determining the wind direction offset as an average of the difference for the group of data.

### Claim 3 (depends on 1)

A method of controlling according to claim 1, wherein the yaw event comprises repeating said steps of determining a control parameter and controlling the wind turbine a number of times.

### Claim 4 (depends on 3)

A method of controlling according to claim 3, wherein the steps are repeated until the measured wind direction parameter is within a pre-defined threshold of zero degrees.

### Claim 5 (depends on 1)

A method of controlling according to claim 1 further comprising obtaining a number of pre-defined wind direction intervals and obtaining a group of data and a wind direction offset for each wind direction interval, and wherein each data set is allocated to a group of data according to the first wind direction parameter in the data set.

### Claim 6 (depends on 5)

A method of controlling according to claim 5, wherein the wind direction parameter is adjusted as a function of the wind direction offset of the wind direction interval comprising the wind direction parameter at the time of adjusting.

### Claim 7 (depends on 1)

A method of controlling according to claim 1 further comprising obtaining a number of pre-defined wind speed intervals and obtaining a group of data and a wind direction offset for each wind speed interval, and wherein each data set is allocated to a group of data according to a wind speed at a time during the yaw event of the data set.

### Claim 8 (depends on 7)

A method of controlling according to claim 7, wherein the wind direction parameter is adjusted as a function of the wind direction offset of the wind speed interval comprising the wind speed at the time of adjusting.

### Claim 9 (depends on 7)

A method of controlling according to claim 7, wherein the wind direction parameter is adjusted by an interpolation function between the wind direction offsets of the different wind speed intervals.

### Claim 10 (depends on 1)

A method of controlling according to claim 1, where a group of data sets is determined over a predetermined time period.

### Claim 11 (depends on 1)

A method of controlling according to claim 1, where a group of data sets is determined based on a predetermined number of data sets in the group.

### Claim 12 (depends on 1)

A method of controlling according to claim 1, where the steps of obtaining a group of data sets and determining a wind direction offset are repeated at time intervals.

### Claim 13 (depends on 1)

A method of controlling according to claim 1, where the steps of obtaining a group of data sets and determining a wind direction offset are repeated a predefined number of times.

### Claim 14 (depends on 1)

A method of controlling according to claim 1, where the adjusting of the wind direction parameter comprises subtracting the wind direction offset times a gain factor smaller than one, wherein the gain factor is in the interval of 0.1-0.95, such as in the interval of 0.4-0.6, such as equal to 0.5.

### Claim 15 (depends on 1)

A method of controlling according to claim 1, where the wind direction parameter is further adjusted as a function of earlier wind direction offsets.

### Claim 16

A control system for a wind turbine configured to perform the steps of:
receiving a first wind direction parameter as measured by a wind direction sensor, wherein the wind direction parameter is indicative of the wind direction relative to the wind turbine;
performing a yaw event comprising the steps of determining a control parameter of the wind turbine as a function of the wind direction parameter, wherein the control parameter comprises a yawing parameter for the wind turbine, and controlling the wind turbine according to the control parameter, wherein the controlling comprises yawing the wind turbine according to the yawing parameter;
receiving a wind direction parameter as measured by the wind direction sensor after said yawing event;
determining a data set comprising the first wind direction parameter, a wind direction sensor angle determined as a difference in the measured wind direction parameter before and after the yawing event, and a yaw angle indicative of the yawing performed during the yawing event;
obtaining over time a group of data sets;
determining a wind direction offset from the group of data sets;
adjusting the wind direction parameter as a function of the wind direction offset, and
applying the adjusted wind direction parameter in the controlling of the wind turbine.

### Claim 17

(canceled)

### Claim 18

A wind turbine, comprising:
a tower;
a nacelle disposed on the tower;
a rotor extending from the nacelle;
a plurality of blades connected to the rotor;
a wind sensor configured to detect a direction of a wind;
a yawing system; and
a control system configured to perform an operation, comprising:
measuring a first wind direction parameter by the wind direction sensor;
performing a yaw event, comprising:
determining a control parameter of the wind turbine as a function of the wind direction parameter, wherein the control parameter comprises a yawing parameter for the wind turbine, and
controlling, by the yawing system, the wind turbine according to the control parameter, wherein the controlling comprises yawing the wind turbine according to the yawing parameter;
measuring a wind direction parameter by the wind direction sensor after said yawing event;
determining a data set comprising the first wind direction parameter, a wind direction sensor angle determined as a difference in the measured wind direction parameter before and after the yawing event, and a yaw angle indicative of the yawing performed during the yawing event;
obtaining over time a group of data sets;
determining a wind direction offset from the group of data sets;
adjusting the wind direction parameter as a function of the wind direction offset, and
applying the adjusted wind direction parameter in the controlling of the wind turbine.