Nonlinear control strategies for a floating wind turbine with PMSG in Region 2: A comparative study based on the OpenFAST platform

Abstract

This study examines new control strategies for floating offshore wind turbines (FOWTs) equipped with permanent magnet synchronous generators (PMSG), and operating in Region 2. The aim is to maximize power production while minimizing fatigue loads within wind speed limits. This is achieved by maintaining optimal tip speed ratio (TSR) using diverse control strategies. Control design based on the OpenFAST model is not trivial due to FOWTs’ dynamics. Adaptive gain versions of super-twisting (STW) control methods are proposed to address this, requiring minimal system knowledge while simplifying controller gains tuning. These controllers also adapt to parameter changes, ensuring robustness. A comparative analysis of STW-based control versus baseline control demonstrates its effectiveness in maximizing power production under numerous different conditions.