METHOD FOR CONTROLLING A WIND TURBINE DURING SHUTDOWN

摘要

A method for controlling a wind turbine during shutdown is disclosed, said wind turbine comprising a rotor carrying at least three wind turbine blades adapted to be pitched individually. A first shutdown strategy is initially selected, and subsequently a second shutdown strategy is selected, the second shutdown strategy ensuring alignment of the pitch angles of the wind turbine blades. The time for switching from the first shutdown strategy to the second shutdown strategy is calculated on the basis of a misalignment of the pitch angles, and in order to align the pitch angles before an estimated point in time where the pitch angles must be aligned, in order to avoid excessive asymmetric loads on the wind turbine blades and/or on the rotor. According to an alternative embodiment, the first shutdown strategy includes moving the wind turbine blades towards a feathered position at identical pitch rates.

主权项

1. A method for controlling a wind turbine during shutdown, said wind turbine comprising a rotor carrying at least three wind turbine blades adapted to be pitched individually, the method comprising:
receiving a shutdown command for stopping operation of the wind turbine, obtaining a measure for a misalignment of the pitch angles of the wind turbine blades, calculating a time required for aligning the pitch angles of the wind turbine blades, based on said measure for a misalignment, estimating a point in time where the pitch angles of the wind turbine blades should be aligned, moving the wind turbine blades towards a feathered position in accordance with a first shutdown strategy until the time remaining until the estimated point in time corresponds to the time required for aligning the pitch angles of the wind turbine blades, or until one or more predefined criteria is/are fulfilled by the wind turbine, and subsequently moving the wind turbine blades towards a feathered position in accordance with a second shutdown strategy, said second shutdown strategy providing alignment of the pitch angles of the wind turbine blades.