Comparative study of dual-cylinder system with permanent magnet linear generator for wave energy conversion
Additional Document Info
Copyright 2016 by the International Society of Offshore and Polar Engineers (ISOPE). Based on the highest energy density and constant availability, ocean waves are regarded as one of promising renewable energy resources and a number of permanent magnet linear generators (PMLGs) have been designed to generate electricity out of the ocean wave energy. The PMLGs generate from the relative motion of two bodies, an armature (coil part) and a permanent magnet. A challenge in design of the PMLG-based system is to maximize the relative motion to amplify power output, and resonance can be a solution. In this study, a comparative study is carried out between numerical simulations and experiments for a PMLG system designed by Jeju National University. As a single phase alternator system, it consists of the permanent magnetic bar attached to an outer cylinder and the shorter armature fixed to an inner cylinder. Both cylinders are freely floating and moon pool exists between the cylinders. The two-body system has natural frequencies placed in the range of target main wave energy to amplify the power production. Both motions of the floating bodies and power outputs are investigated after confirmation of numerical scheme to calculate the power output without considering the coupled motions. After motion response amplitude operators (RAO) are compared in frequency domain with generator uncoupled, time-domain motion responses and power outputs to random waves are compared with the generator coupled.