Feedforward control of a floating offshore wind turbine-generator system based on wind speed preview using a nacelle-mounted lidar

Abstract

To reduce both the platform motion and dynamic loads of floating offshore wind turbine-generator systems, feedforward control for high wind speed regions is developed by combining with the wind speed previewed by a nacelle-mounted lidar. First, the wind speed preview using a nacelle-mounted lidar was simulated by considering the floating platform velocity and the temporal difference of laser casting. Feedforward control, in which the blade pitch is manipulated according to the previewed wind speed so as to maintain the rated generator speed, is combined with gain-scheduling feedback control of the generator speed. This feedforward control is characterized by employing the first-order lag filter with the delay compensator for the previewed wind speed. The effectiveness of the developed feedforward-feedback controller is analyzed through an aero-elastic-hydro-control coupled nonlinear dynamic simulation of a 5-MW floating offshore wind turbine-generator system under turbulent wind fields and irregular wave height variations.