Control Oriented Dynamic Modeling of a Tension-Leg Platform Based Floating Offshore Wind Turbine With Dynamic Vibration Absorbers

Abstract

Due to platform motions, floating offshore wind turbine loads are increased. Among proposed platform concepts, tension leg platform introduces least wind turbine load increase. To reduce wind turbine loads, extra actuators have been added to the platform to suppress the tension leg platform motion. For these actuators controller design, it is critical to derive a mathematical model of the platform-wind turbine-actuator system. In this paper, a reduced 13 DOFs model is derived using Lagrange equation and validated with simulation results from FAST. This reduced model is simple, but accurate enough to predict wind turbine and platform response under wind and wave disturbance. Based on the proposed model, an LQR controller is designed. One simulation case shows that the wind turbine tower load can be effectively reduced by actively controlled DVAs.

Platform stabilization and load reduction of floating offshore wind turbines with tension‐leg platform using dynamic vibration absorbers

“…Ramachandran ignores the tower DOFs in the side‐side direction . In the authors' previous work, a 13‐DOF model was built; however, it cannot include the impact of wind direction. In this paper, we develop an 11‐DOF model which can handle arbitrary wind direction.…”

“…Nihei et al conclude that the TLP shows the best performance by experimental evaluations for four platforms using scaled models . Despite its good performance in suppressing tower load increase, there remains room for TLP to further decrease the tower loads by deploying actively controlled dynamic vibration absorbers (DVAs) on the platform or the semiactive TMD in the nacelle . The advantages of using DVAs for platform motion stabilization include simplicity in structural design, cost‐effectiveness in deployment, and consistency in performance with properly designed controllers.…”

“…Based on the authors' previous work, this paper presents a more in‐depth study on DVA‐based TLP‐FOWT control, in terms of the design of passive DVA, dynamic modeling of TLP‐FOWT‐DVA system, active DVA controller design, and performance evaluation. The remainder of this paper is organized as follows.…”

“…32 Despite its good performance in suppressing tower load increase, there remains room for TLP to further decrease the tower loads by deploying actively controlled dynamic vibration absorbers (DVAs) on the platform or the semiactive TMD in the nacelle. 27,33,34 The advantages of using DVAs for platform motion stabilization include simplicity in structural design, cost-effectiveness in deployment, and consistency in performance with properly designed controllers. In addition, installation of DVAs at the spokes of TLP, rather than inside the platform or tower top, requires limited modifications to the platform or wind turbine.…”