Adaptive Power Regulation Control for Floating Wind Turbines With Guaranteed Transient Performance

Floating offshore wind turbines (FOWTs) hold significant potential for developing wind energy in deep-sea areas. However, they are prone to additional motions, heavy workloads, and undesirable fluctuations under combined wind-wave loads. To tackle these issues, this paper presents a novel adaptive blade pitch control strategy with guaranteed transient performance for FOWTs operating in above-rated wind speed regions. This strategy effectively suppresses platform pitch motion to enhance system stability while maintaining the power output at its rated value. Specifically, this method initiates by defining a filtered regulation error to solve the non-affine nature of its model. An adaptive blade pitch controller is subsequently proposed, integrating an online learning approximator to cope with the unknown dynamics caused by unmeasurable external environmental inputs and model uncertainties. To further mitigate approximation errors, a nonlinear robust control law with adaptive gains is employed, enhancing the robustness and adaptive capabilities of the controller. Superior to the traditional adaptive controllers, a significant advantage of this strategy is its ability to quantify and ensure regulatory performance within predefined constraints during both transient and steady-state stages, thereby achieving high-performance control in power regulation. Finally, simulation studies are conducted using the OpenFAST software to show the capability of the presented blade pitch controller, which guarantees stable power generation with guaranteed transient performance. Note to Practitioners—This paper addresses the need for floating offshore wind turbines (FOWTs) to develop a control mechanism that simultaneously mitigates platform motion and regulates power production in the above-rated wind speed regions. In practice, neglecting the effects of floating platform motions on the controlled system can significantly degrade the performance of FOWTs, resulting in unexpected power fluctuations and increased mechanical loads. To this end, we propose an adaptive blade pitch control strategy that utilizes the function approximator technique and specifically incorporates platform pitch motion into the controller design. This approach effectively balances the dual demands of platform stabilization and power regulation, aligning the control strategy with practical requirements. Furthermore, the proposed controller ensures that power regulation errors remain within predefined limits, thereby enhancing both transient and steady-state performance and better matching the actual operational conditions of FOWTs.