This paper presents the effects of a nonlinear Power Take Off (PTO) on the response of a simple Wave Energy Converter (WEC) to the waves. The current WEC is a self – contained, slack moored point absorber, with the PTO operating from an inertial mass within the device.
A linear numerical model is used to choose the experimental model parameters - such as the internal mass, and spring constants – for both maximising the relative motion between the inertial mass and the body and maximising power extraction. A 1:40 scale experimental model has been built and tested in Edinburgh University’s curved tank. The motions of the model for regular sinusoidal monochromatic waves have been observed and for different setups of the PTO. It was found that the amplitude of the device response varied but the frequency and shape of the response profile remained constant. A double frequency sea was also used to see if nonlinear effects were present in the overall motion and they were indeed found to be present in some of the setups. This shows that having some nonlinearities present in PTO has an effect on the overall motion.
