Wind tunnel testing of power maximization control strategies applied to a multi-turbine floating wind power platform

Large-scale offshore floating wind turbines represent one of the most significant engineering challenges in wind energy at present. Since current fixed-bottom technology can support deployment up to water depths of about 30 m (shallow waters), the technology is now moving towards deeper waters, where the wind resource is extremely abundant. In this regard, single and multi-turbine floating platforms are now being actively investigated. This paper presents the results of a wind tunnel experimental campaign conducted with the scaled model of a square-shaped floating platform equipped with four wind turbine models located at its corners. The scaled wind turbines feature pitch, torque and yaw control, and are equipped with sensors measuring all main operational parameters, including rotor and tower loads. The models also provide a realistic energy conversion process, due to similar rotor aerodynamic performance, loads, and wake characteristics between the scaled and full scale machines. The pitch floating motion of the scaled platform is obtained by a custom-designed one degree-of-freedom actuator, capable of performing specific motion laws simulating different wave conditions. Measurements are taken to characterize the wake, including the quantification of wake interference on downstream machines. The potential effect of yawing and derating the upstream wind turbines is then investigated in terms of overall power production.