Patent ID: 11959460
Assignee: VESTAS WIND SYSTEMS A/S
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F  Y | IPC F

Claim 17:
18. A computer program product comprising a non-transitory computer readable medium having software code which, is adapted to control a wind turbine comprising a rotor with one or more pitch adjustable rotor blades, the computer program product being adapted to perform an operation for controlling the wind turbine, the operation comprising:
implementing a stopping process by a stop controller in response to a rotor stop signal, the stopping process reducing speed of the rotor by controlling the one or more pitch adjustable rotor blades towards a feathering position at a number of pre-set pitch rates including a first pitch rate and a second pitch rate, the second pitch rate being lower than the first pitch rate, wherein the stop controller is configured to:
access desired pitch angles of the stopping process, the desired pitch angles defining a pitch trajectory across an entire duration of the stopping process;
define an envelope band of the pitch trajectory by adding positive values and negative values thereby defining an upper band and a lower band of the pitch trajectory across the entire duration, or until a termination criterion has been reached; and
move the one or more pitch adjustable rotor blades at a selected pitch rate among the number of pre-set pitch rates until a pitch angle signal is outside a pitch angle value defined by the envelope band such that:
when the pitch angle signal is larger than the upper band at a specific time, the selected pitch rate is changed to the second pitch rate; and
when the pitch angle signal is smaller than the lower band at a specific time, the selected pitch rate is changed to the first pitch rate.