A novel proposal of PTO direct-drive linear generator, an Azimuthal Multi-translator Switched Reluctance Machine (AMSRM)

Abstract

Research and development on power take-off (PTO) in wave energy has been gaining relevance in recent years, appearing as a priority in various forums (JCR reports, SRIA in wave energy development, specific research funding program in WES, etc.). A new proposal of a linear electric generator to act as a PTO in wave energy extraction applications has been developed in the European project SEATITAN. In particular, the scalable and modular PTO has been designed to be adapted to four different wave energy converters of heaving point absorber type. The linear generator is based on a technology of multi translator switched reluctance machine in which the magnetic flux is azimuthal. This topology allows reducing the amount of magnetized material needed and increasing the force density, besides having a cylindrical shape that allows adapting perfectly to the spar of point absorber type WECs. The Azimuthal Multi-translator Switched Reluctance Generator (AMSRG) has been completely developed and a prototype composed by two modules of 35 kN of force and 3 m/s of peak velocity has been manufactured. The manuscript details the design and manufacturing process as well as the characterization and validation tests. Those dry tests, delivered at the lab, comprise: the force characterization, the electric losses measurement, the dynamic characterization of frictional losses and a preliminary setting of control parameters.