[1] Univ Fed Minas Gerais, Grad Program Elect Engn, BR-31270901 Belo Horizonte, MG, Brazil
[2] Norwegian Univ Sci & Technol, Dept Elect Power Engn, N-7491 Trondheim, Norway
[3] Univ Fed Itajuba UNIFEI, Inst Ciencias Tecnol ICT, BR-35903087 Itabira, Brazil
[4] Univ Trento, Dept Ind Engn, I-38122 Trento, Italy