1. Fraunhofer Institute IFF,Energy systems and infrastructures,Magdeburg,Germany
2. Fraunhofer Institute IFF, University of Applied Sciences Magdeburg-Stendal,Energy systems and infrastructures,Magdeburg,Germany
3. University of Tor Vergata,Rome,Italy
4. University of Bari,Department of agro-envrironmental and territorial sciences,Bari,Italy
5. Christian-Albrechts-University,Chair of Power electronics,Kiel,Germany