1. Grad. Program in Elec. Eng. sFederal Univ. of Uberlândia (UFU),Uberlândia,MG,Brazil
2. Federal Univ. of São João del-Rei (UFSJ),Electrical Engineering Department (DEPEL),São João del-Rei,MG,Brazil
3. Electrical Engineering Faculty (FEELT) Federal Univ. of Uberlândia (UFU),Uberlândia,MG,Brazi