1. School of Energy Systems, LUT University,Department of Electrical Engineering,Lappeenranta,Finland,53850
2. Aalborg University,Department of Energy Technology,Aalborg,Denmark,9220
3. University of Aveiro,Department of Industrial Engineering and Management,Aveiro,Portugal
4. University Portucalense Infante D. Henrique (UPT), R. Dr. António Bernardino de Almeida,Porto,Portugal,4200-072