Pitch Control of Large Wind Turbines During the Shutdown Operation

In this contribution, the control for the shutdown operation of a very large wind turbine is studied. The control scheme uses the standard control infrastructure, which is available in the machine, but the control system is reconfigured according to the needs of the shutdown control problem.The classic collective pitch control (CPC) system, which operates as a regulator, is complemented with a feedforward control scheme to improve responsiveness and is reconfigured as a reference tracking control problem with restrictions. The restrictions are treated with an anti-windup strategy for magnitude and rate. The effectiveness of the approach is studied by simulations using a 20 MW reference wind turbine.