Horizontal axis wind turbine

Abstract

A horizontal axis wind turbine is disclosed. When a wind direction changes to blow against a rotor from a rear side, a pitch angle of a rotor blade of the rotor are controlled to reverse a rotation of the rotor, without turning of the rotor to the rear side.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2005-011225, filed on Jan. 19, 2005, and the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a horizontal axis wind turbine, and more particularly to a horizontal axis wind turbine in which a rotating direction of a rotor changes according to a change of the wind direction by, for example, changing pitch angles of rotor blades, and further the direction of the wind turbine can be changed appropriately according to the change of the wind direction at its placed position. [0004] 2. Description of the Related Art [0005] There has been known a horizontal axis wind turbine of downwind type, for example, as shown in FIG. 5, as a conventional example of a horizontal axis wind turbine which performs direction control ac...

AI Technical Summary

Benefits of technology

[0008] An object of the invention is to provide a horizontal axis wind turbine that is not complicated in installation work and relatively flexible in correction after installation with respect to controlling an azimuth angle and a tilt angle according to a change of wind direction.

[0010] Accordingly, because the change of pitch angle of the blades and the reverse in the rotating direction of the rotor can be performed without turning movement of a nacelle which was required by the above-described conventional example, installation work is not complicated due to omission of work for rotating the nacelle, and correction after installation becomes easier. As a result, the cost for maintenance can be cut down.

[0011] Preferably, the horizontal axis wind turbine comprises: a nacelle to support the rotor; a tower head which the nacelle is mounted on and comprises a rail with a circular or arc shape thereon; and a roller to support the nacelle, which is movable on and guided by the rail, to control an azimuth direction of the wind turbine. In the horizontal axis wind turbine, each roller is moved on the rail with a circular or arc shape, in a limited range to correspond to the change of wind direction in the range, which allows the wind turbine to be adjusted within a narrow range for the wind direction in the azimuth-angle direction.

[0013] According to such a horizontal axis wind turbine, the inclination angle can be controlled by extending and retracting the actuators without producing a special cam track which was required by the above-described conventional example, therefore installation cost can be reduced including omission of work to lift a large cam, and further a horizontal axis wind turbine more precisely facing the wind direction can be implemented.

[0021] The horizontal axis wind turbine according to the invention allows the pitch angle of blades to be changed and the rotating direction of the rotor to be reversed when the wind turbine is fixed at a place where the wind direction is almost constant as for the seasons, or as in a coast side or a mountain side where a wind from the sea or an upflow wind blows in the daytime and a land wind or a downflow wind blows at night. Further, when the wind turbine is installed at a place where wind directions are changeable, in addition to the above-described changes of the pitch angle and the reverse of rotation, the wind turbine follows the azimuth direction of a wind using the rails and the rollers rotatably moving thereon, and controls the inclination angle by up-and-down control of the actuators to coincide with the wind direction. Accordingly, the wind turbine of the invention has advantages in that installation can be relatively easier and the change after the installation can be also easier.

Problems solved by technology

According to such a structure, the cam tracks have to be produced having different values of tilt angles correlative to azimuth angles for every installing position, and further a difficulty occurs in work for correcting the angle once set.

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