The perspective of fossil-based fuels exhaustion in the next decades created the need of new types of energy resources; amongst them the renewable energies (wind, solar, wave, etc.) are of great perspective. The most popular is the wind energy, with a total installed power of 47.000 Mw . The exclusive use of wind farms is not practical, due to the high number of units necessary to cover the total energy need , so the development of the other types of renewable energies is a priority. Wave energy conversion devices have become a domain of high interest in the last years, due to the enormous energy potential of the oceans, which are covering more than 2/3 of the Earth's surface.
The usable energy of the oceans is of two types: tidal and wave energy. Conventional devices for wave energy conversion usually include mechanical interfaces such as hydraulic systems, used to convert the slow reciprocating motion of the waves into high speed rotational motion (usually 1500 rpm), suitable for conventional electric generators such as the induction machine. A new solution, which implies the use of linear electric generators, has been proposed in the latest years, with specific advantages and problems.