A control cost criterion for controller tuning of two- and three-bladed 20 MW offshore wind turbines

Abstract

© 2020 Published under licence by IOP Publishing Ltd. When wind turbine concepts are modified, the difference in characteristic behavior and the impact on the cost of energy are of great interest. However, before comparing it is mandatory to re-adapt controller gains or weights to altered turbine dynamics in order to guarantee a still suitable overall system design. As an expenditure-based solution, the proposed control cost criterion could help to assess changes of turbine concepts better due to a clear and objective controller tuning. Conflicting design objectives are therefore assessed on their approximated influence on the cost of energy in order to result in the most cost-beneficial trade-off. These objectives are variations of component loads, actuator usage, and energy production. The criterion is applied to three-and two-bladed 20 MW offshore turbines with turbulent wind for full load operation, exemplarily. This provides insight into the benefits and limitations of low controller integral pitch gains and results in potential cost reductions for all turbines.