1. Engenharia Elétrica, Universidade Federal do Espirito Santo, Vitoria, ES, Brazil
2. Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
3. Electrical Engineering, Federal University of Minas Gerais School of Engineering, Belo Horizonte, MG, Brazil
4. Petrobras, Rio de Janeiro, Brazil
5. Departament of Electrical Engineering, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil