Control of the Platform of an Offshore Wind Turbine

This paper addresses the control of the platform of a floating wind turbine. The floating wind turbine consists in a semi-submersible type platform and a 5 MW wind turbine. The platform pitch was identified as the platform critical motion. Since a non null pitch can displace the rotor plane from its perpendicular position in relation to wind direction, control mechanisms were introduced in the platform in order to control the platform pitch. Two controllers were developed, a proportional-integral-derivative (PID) controller and a pole placement controller. With both controllers it was possible to guarantee a null pitch and so maintain the rotor plane in its perpendicular position in relation to wind direction.