A linear frequency domain model has been developed to simulate the behaviour of a heaving point absorber, moving with respect to a floating reference. A linear external damping coefficient is applied to enable power absorption and a supplementary mass is introduced to allow for tuning the point absorber to the incoming wave conditions.
Two motion restrictions are applied to the buoy. The first restriction decreases the occurrence probability of slamming; the second one limits the stroke of the relative motion between the buoy and the platform.
The influence of the motion restrictions on power absorption is examined. Optimal values for the external damping and motion control parameters are determined under the given conditions. A sensitivity analysis on these values is conducted to know the effects of less optimal tuning and/or damping on power absorption. The forces associated with these parameters have to be realized by the power take-off and motion control system respectively. The sensitivity analysis allows for assessing the influence on the power extraction of restrictions applied on these forces.