Yaw system for a windmill

Abstract

The present invention relates to a yaw systemfor a windmill, the windmill comprising a towerand a nacelle, the tower and the nacelle being joined by the yaw system and the yaw system further comprising a bearing fixed to the tower, on which bearing the nacelle rests and slides in a yawing movement, and at least one yaw motor arranged to allow the nacelle to perform a rotary motion along the bearing, wherein the yaw systemfurther comprises control meansfor continuously operating the at least one yaw motor in such a way that the yaw motor strives to maneuver the nacelle according to a setpoint. The invention also relates to a method for controlling the yaw of a windmill, comprising the steps of determining a set point for the windmill, calculating a yaw error based on the set point and a current alignment of the windmill, determining a size and direction of a torque based at least on the yaw error, and applying the torque to at least one yaw motor of a yaw system for turning the turbine, whereby the method also comprises the step of continuously calculating the yaw error and applying the torque in order to strive towards the setpoint.