1. Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ, United Kingdom
2. Department of Physics and Stephenson Institute for Renewable Energy, University of Liverpool, Liverpool L69 7ZF, United Kingdom
3. ENEA, Frascati Research Centre, via E. Fermi 45, 00044 Frascati, Italy
4. Department of Engineering, University of Liverpool, Brownlow Hill, Liverpool L69 3GH, United Kingdom
5. School of ICT, KTH Royal Institute of Technology, Isafjordsgatan 22, 164 40 Kista, Sweden
6. CEMES-CNRS and Université de Toulouse, nMat group, BP 94347, 31055 Toulouse Cedex 4, France