[1] Univ Henri Poincare, CNRS, Grp Rech Electrotech & Elect Nancy, UMR 7037, F-54506 Vandoeuvre Les Nancy, France
[2] Inst Natl Polytech Lorraine, CNRS, Grp Rech Electrotech & Elect Nancy, UMR 7037, F-54501 Vandoeuvre Les Nancy, France
[3] Ecole Natl Super Elect & Mecan, F-54516 Vandoeuvre Les Nancy, France