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

Claim 13:
14. A wind turbine comprising a control system and a rotor with one or more pitch adjustable rotor blades, the control system being arranged for controlling the wind turbine in response to a rotor stop signal, wherein the control system comprises:
a stop controller arranged for controlling the one or more pitch adjustable rotor blades towards a feathering position in response to the rotor stop signal as part of a stopping process, and wherein the stop controller is arranged to pitch the one or more pitch adjustable rotor blades 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 arranged 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 to the desired pitch angles, 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;
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.