General Conclusion

Abstract

At present, the horizontal-axis WECS are characterized by a great variety, due to the different solutions adopted as regards their structure, components and operating regimes. These solutions depend largely on the WECS rated power. Thus, lowpower (one to tens of kW) and medium-power WECS are integrated either into distributed power production systems or into hybrid renewable energy conversion systems operating in isolated grids. Grid-connected WECS rated powers have moved from the range 600–1000 kW to values of 3–6 MW in the last decade. The multi-megawatt WECS are nowadays representative for the technological state-of-the-art. On the other hand, the impact of the small-scale distributed power production systems, operating close to the consumption location, is getting higher and higher. Consequently, the whole range of WECS rated powers is of interest, their configurations and operation modes being very diverse. For all the mentioned WECS the control problem is important, both for power limiting in high winds and also for energy optimization below rated winds.