1. Enerdata. Global Energy Statistical Yearbook 2015 [Online]. Available:
http://yearbook.enerdata.net/
2. British-Petroleum, “BP World Energy Outlook 2030,” January, 2013.
3. J. Rodríguez, S. Bernet, B. Wu, J. O. Pontt, and S. Kouro, “Multilevel voltage-source-converter topologies for industrial medium-voltage drives,” IEEE Trans. Ind. Electron., vol. 54, no. 6, pp. 2930–2945, 2007.
4. Wikipedia. (2012). Power Semiconductor Device. Available:
http://en.wikipedia.org/wiki/Power_semiconductor_device
5. W. McMurray, “Fast response stepped-wave switching power converter circuit,” US Patent 3581212, 1971.