Comparative Analysis of Decoupling Control Methodologies and H¥ Multivariable Robust Control for Variable-Speed, Variable-PitchWind Turbines: Application to a Lab-Scale Wind Turbine

摘要

This work is focused on the improvement of variable-speed variable-pitch wind turbineperformance by means of its control structure. This kind of systems can be considered as multivariablenonlinear processes subjected to undesired interactions between variables and presenting differentdynamics at different operational zones. This interaction level and the dynamics uncertaintiescomplicate the control system design. The aim of this work is developing multivariable controllers thatcope with such problems. The study shows the applicability of different decoupling methodologiesand provides a comparison with a H¥ controller, which is an appropriate strategy to cope withuncertainties. The methodologies have been tested in simulation and verified experimentally ina lab-scale wind turbine. It is demonstrated that the wind turbine presents more interaction atthe transition zone. Then, this operational point is used as the nominal one for the controllerdesigns. At this point, decoupling controllers obtain perfect decoupling while the H¥ controlpresents important interaction in the generated power loop. On the other hand, they are slightlysurpassed by the robust design at other points, where perfect decoupling is not achieved. However,decoupling controllers are easier to design and implement, and specifically dynamic simplifieddecoupling achieve the best global response. Then, it is concluded that the proposed methodologiescan be considered for implantation in industrial wind turbines to improve their performance.