1. Projects and Works Division (DPROB), Federal University of São João del-Rei, São João del-Rei, Brazil
2. Grad. Program in Elec. Engineering, Federal University of Uberlândia, Uberlândia, Brazil
3. Department of Electrical Engineering (DEPEL), Federal University of São João del-Rei, São João del-Rei, Brazil
4. Faculty of Electrical Engineering Faculty, Federal University of Uberlândia, Uberlândia, Brazil