1. Electrical Machines Laboratory, Department of Electrical and Computer Engineering, Democritus University of Thrace, Kimmeria-Xanthi, 67132 Xanthi, Greece
2. Environmental Physics, Energy and Environmental Biology Laboratory, Department of Environment, Ionian University, Panagoula-Zakynthos, 29100 Zakynthos, Greece
3. Department of Photovoltaic Systems and Distributed Generation, Centre for Renewable Energy Sources and Saving (C.R.E.S.), 19th km Marathonos Av., Pikermi, 19009 Athens, Greece