1. Department of Electrical Engineering, Computing and Automatics, Superior Technical College of Engineering, University of Huelva, Campus El Carmen, Avda. de las Fuerzas Armadas, s/n, 21007 Huelva, Spain
2. Department of Electrical Engineering, Superior Technical College of Engineering, University of Huelva, Campus El Carmen, Avda. de las Fuerzas Armadas, s/n, 21007 Huelva, Spain
3. Department of Electrical Engineering, Superior Polythechnic College of Engineering of Linares, University of Jaén, Avda. de la Universidad s/n, 23700 Linares, Spain