1. Group of electrical engineering Paris, UMR 8507 CNRS, CentraleSupelec Université Paris Sud, Université Pierre et Marie Curie, Paris, France
2. Department of Mechanical Engineering University of Houston Houston TX 77204 USA
3. Department of Electrical Engineering and Computer Science, Montefiore Institute Sart‐Tilman Université de Liège Liège 4000 Belgium