Browse Prior Art Database

North Calibration of Direction Sensor (Yaw Encoder)

IP.com Disclosure Number: IPCOM000198275D
Original Publication Date: 2010-Aug-23
Included in the Prior Art Database: 2010-Aug-23
Document File: 4 page(s) / 109K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

In the field of wind turbines a precise calibration of the turbines direction sensor (yaw encoder) is important. The yaw encoder is responsible for measuring which direction the nacelle is pointing. The direction is measured in degrees and should be zero when the nacelle is pointing directly north. The turbine weather stations are mounted on the nacelles, so the nacelle direction is needed in order to determine the (absolute) wind direction. The direction measurements have several different uses, including data analysis, activation of low noise operation, if a turbine is near living quarters, and park wind direction, if no metrology tower is present. Theoretically, land surveyors are probably able to take a bearing from known objects in the landscape (like a church tower) or from equipment purposely placed in the landscape. Another method uses a magnetic compass when calibrating the yaw encoder. Due to the nacelle being a steel structure the compass readings are rather unreliable and the service staffs often have to stand outside the turbine and judge the nacelle direction from a distance.

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North Calibration of Direction Sensor (Yaw Encoder)

Idea: Rasmus Nielsen, DK-Brande

In the field of wind turbines a precise calibration of the turbines direction sensor (y important. The yaw encoder is responsible for measuring which direction the nac direction is measured in degrees and should be zero when the nacelle is pointing turbine weather stations are mounted
determine the (absolute) wind direction. The direction measurements have several including data analysis, activation of low noise operation, if a turbine is near living wind direction, if no metrology tower is present.

Theoretically, land surveyors are prob
(like a church tower) or from equipment purposely placed in the landscape. Another magnetic compass when calibrating the yaw encoder. Due to the nacelle being a ste compass readings are rather unreliable and the service staffs often have to stand and judge the nacelle direction from a distance.

The novel idea consists in using the sun to determine the nacelle direction.
the earth is time dependent, but well described. Combining that knowledge with i
from GPS (Global Positioning System) makes it possible to determine the nacelle dire measuring the sunlight direction relative to the nacelle or aligning the nacelle in a fixed angle sunlight. Figure 1 shows an illustration of turbine with north, nacelle and sunligh
example the actual nacelle direction is 45

The user performing the calibration will mount a sundial-like device on top of the na
The mounting bracket ensures that zero degrees point along the main shaft,
The actual sun-disc has finer angular graduation than shown in the illustration in Figure 2. For improved readability it can also have lines extending from the center to the edge. So
shows the sunlight direction, relative to the nacelle.

The sunlight direction, relative to the nacelle, is read fr
application on a GPS equipped handheld device (e.g. a cellular phone or a Perso
(PDA)). The application uses the date, time and position information from GPS to
sunlight direction, relative to north. The two directions are combined and the outpu
nacelle direction, relative to north (see Figure 3). If the turbine itself is equipped with GPS or otherwise knows the site coordinates, the application can be integrated into the turbine softwa
the date and time can be read from the turbine clock. When the actual nacelle direct
determined, the yaw encoder can be calibrated to match this value.

In an alternative, simplified use of the same main principle the nacelle is yawed
parallel to the sunlight direction (see Figure 4). A device similar to the sun-disc, or even ju existing antenna and a dot painted on the nacelle roof, can assist the user when ali
(see Figure 5). An application on a handheld, GPS equipped device uses the date, t information from GPS to calculate the sunlight direction, relative to north, whic
direction (see Figure 6). If the turbine itself is equipped with GPS or the site coordinate known, the application may be integra...