1. VTT Technical Research Centre of Finland, P.O. Box 1000, 02044 VTT, Finland
2. School of Electrical, Electronic and Mechanical Engineering, University College Dublin
3. Risoe National Laboratory for Sustainable Energy, Technical University of Denmark
4. National Renewable Energy Laboratory, USA
5. Fraunhofer Institute for Wind Energy and Energy System Technology IWES, Kassel, Germany
6. VTT Technical Research Centre of Finland
7. Department of Electrical Sustainable Energy, Delft University of Technology, the Netherlands