Offshore Wind Turbine Controls

Offshore wind turbines distinguish themselves from their land‐based counterparts in several important respects. Economies of scale and challenging maintenance access dictate large turbine variants, typically with power generating capacities in excess of 3 MW. This chapter describes the offshore reference turbine (ORT) in more detail. It focuses on the system dynamics of an offshore wind turbine, rather than advanced control algorithms, discussing controls based on embedded dynamic models (Kalman filters and their extensions). The chapter examines the functions which the controller is required to perform – rotor speed control, load rejection, damping and power command tracking – along with the sensors and actuators with which it has to work. The primary objective of the wind turbine controller is to keep the rotor speed of the wind turbine within limits, as it generates power. The chapter addresses the problem of controlling large bottom‐fixed offshore wind turbines.