On the dynamics of a novel ocean wave energy converter

Buoy-type ocean wave energy converters are designed to exhibit resonant responses when subject to excitation by ocean waves. A novel excitation scheme is proposed which has the potential to improve the energy harvesting capabilities of these converters. The scheme uses the incident waves to modulate the mass of the device in a manner which amplifies its resonant response. To illustrate the novel excitation scheme, a simple one-degree of freedom model is developed for the wave energy converter. This model has the form of a switched linear system. After the stability regime of this system has been established, the model is then used to show that the excitation scheme improves the power harvesting capabilities by 25-65 percent even when amplitude restrictions are present. It is also demonstrated that the sensitivity of the device's power harvesting capabilities to changes in damping becomes much smaller when the novel excitation scheme is used. (C) 2010 Elsevier Ltd. All rights reserved.