Experimental Study of a Wave Energy Converter Using a Unidirectional Cascaded Gear System in a Short-Wave Period

Abstract

A wave energy converter (WEC) based on a direct mechanical drive system (DMDS) exhibits limited performance when the sea state stands for a short period. This study aims to increase the efficiency of a WEC-DMDS mechanical system applied under short-wave conditions. A novel WEC is designed by applying cascaded gear and reducing the flywheel inertia to achieve better efficiency in a short-wave period. By applying a short-wave period of less than 2.84 s for the actual scale, the UCG-WEC can produce a CWR of 18.5%, mechanical efficiency of 87%, and a maximum power of 200 W. These values are much better than those obtained previously, where zero efficiencies were achieved for the same wave period range. In addition, this model performs well under both high-and low-wave steepness conditions. This study also evaluates variations in lever length and effective height. The C-type configuration, with a relative length ratio of 0.74, is found to be the optimal choice.