Fuzzy logic tuning of a PI controller to improve the performance of a wind turbine on a semi-submersible platform under different wind scenarios

Abstract

The integration of renewable energy sources in power systems, specially wind energy, is growing as environmental concerns arise in society. Nevertheless, the low amount of viable sites onshore or in shallow waters restricts the use of wind energy. In this sense, offshore semi-submersible platforms appear as an option, which in addition enables the integration of complementary elements, for instance wave energy converters. However, the complexity of the system increases due to the interactions between the platform movements and the wind turbine, and traditional control techniques do not enable to cope with these interactions in an easy way, hence limiting the efficiency of energy harvesting. Intelligent control techniques are an option with a great potential to take full account of the said interactions and to improve energy production efficiency. Still, it is required to have simulation models including those effects beforehand, so that the effects of a designed controller on the system can be evaluated. This paper presents an original fuzzy logic controller that tunes a reference controller, improving its performance according to a developed methodology that allows evaluation of controllers for wind turbines in semi-submersible platforms. The resulting fuzzy logic controller allows higher efficiency concerning mechanical loads in the system, electric energy production and tracking error of the speed reference.