Dynamics of a hybrid wave-current energy converter with a novel power take-off mechanism

Abstract

This paper introduces a hybrid wave-current energy converter (HWCEC) that simultaneously harvests energy from current and waves. Wave energy is extracted through relative heaving motion between a floating buoy and a fully submerged second body. Current energy is extracted using a hydro turbine. A mechanical motion rectifier (MMR) based on one-way clutches merges the separate current and wave power inputs and converts bidirectional, up-and-down wave input motion into unidirectional rotation of the generator shaft through different engagement statuses of the set of one-way clutches. A time domain simulation is conducted with hydrodynamic coefficients obtained from computational fluid dynamics software and boundary element software. Simulation results show an improvement in output energy and peak to average ratio compared to both turbine and point absorber wave energy converters acting individually.