Rotating three-dimensional ultrasonic anemometer and method of measuring three-dimensional wind velocity using the same

A three-dimensional (3D) wind velocity measuring method comprising:

• receiving a 3D sensed wind velocity on a sensing coordinate system, which is sensed by a 3D ultrasonic anemometer that is installed at a rotation body rotating around a rotation axis and rotates around the rotation axis together with the rotation body;
• receiving a rotation angle φ of the rotation body;
• and
• converting the 3D sensed wind velocity on the sensing coordinate system into a 3D fixed wind velocity on a fixed coordinate system by using the rotation angle φ.

A wind turbine comprising:

• a hub rotating along a rotation axis;
• rotation blades installed at the hub to rotate the hub by wind power;
• a nacelle generating electricity by the rotation of the hub;
• a three-dimensional (3D) ultrasonic anemometer outputting a 3D fixed wind velocity on a fixed coordinate system;
• and
• a controller controlling at least one of a pitch angle of the rotation blades and a yaw angle of the rotation axis by using the 3D fixed wind velocity,
• wherein the 3D ultrasonic anemometer comprises:
• an ultrasonic sensor comprising three pairs of ultrasonic transceivers arranged in different directions, wherein the ultrasonic sensor is installed at a spinner of the hub rotating around the rotation axis and rotates around the rotation axis together with the hub;
• a signal processor outputting a 3D sensed wind velocity on a sensing coordinate system sensed by the ultrasonic sensor;
• and
• a coordinate converter converting the 3D sensed wind velocity into the 3D fixed wind velocity by using a rotation angle φ of the hub.