First and foremost, I would like to thank my thesis director Dr. Eng. Carlos Álvarez Bel for his guidance and dedicated time. Most especially, I would like to express my gratitude to him for giving me the opportunity and the framework to develop this dissertation. My most sincere thanks also go to Prof. Claudio Cañizares, from the University of Waterloo for giving me the opportunity to do an International Visit in his group and partially develop my thesis during the 5 months I stayed in Canada. The numerous meetings we had give me the opportunity to improve my skills in electrical engineering research. I would also like to thank Javier Rodríguez García who was like a second director for me, giving me valuable contributions for the thesis and his encouragements when I encountered difficulties.