Design and Analysis of a Field-Modulated Tubular Linear Permanent Magnet Generator for Direct-Drive Wave Energy Conversion

A two-body buoys power generation system using the field-modulated tubular linear permanent magnet generator (FM-TLPMG) is proposed for direct-drive wave energy conversion in this paper. The traditional linear generator has disadvantages of large weight and low-power density caused by the slow speed of ocean wave. The FM-TLPMG can overcome these disadvantages in some extent through accelerating the speed of the traveling magnetic field. In order to design a suitable FM-TLPMG for the direct-drive wave energy conversion in a short time, ocean wave theory is applied to analyze hydrodynamic problems of the two-body buoys and calculate the operating velocity of FM-TLPMG in the sea. A 2-D analytical model for FM-TLPMG design is presented to obtain the electromagnetic field distribution by solving the Laplace and Poisson equations for each region. The analytical result has been compared with the finite-element analysis and shows its validation for the design.