Control co-design of a floating offshore wind turbine

Several control co-design (CCD) optimizations of floating offshore wind turbines are presented in this work using the newly introduced Wind Energy with Integrated Servo-Control (WEIS) framework. Three methods for parameterizing the primary tuning inputs to the Reference Open-Source Controller are presented and optimized, including a sensitivity-margin constrained controller. WEIS, a detailed, open-source floating offshore wind turbine design optimization tool is then used to conduct CCD optimizations on the International Energy Agency (IEA) 15MW wind turbine on the University of Maine VolturnUS-S semisubmersible platform. The results from optimizations are shown to reduce the levelized cost of energy (LCOE) by approximately 1% and 4% when optimizing the tower and platform, respectively. It is also found that the coupling between the tower and control system parameters is weaker than the coupling between the floating system and control system parameters, showing that CCD may not be advantageous for certain problems. Finally, a subset of operational design load cases is run to verify the optimized controller and turbine models.