Power-take-off control in a scaled experiment of a point absorber wave energy converter

Abstract

This paper investigated the design of a power-take-off control system for the study of a model scaled point absorber wave energy converter in a wave flume experiment, where the scale of the experiment must be kept low to reduce the blockage effects of the buoy in the wave flume. In keeping the model small, the parasitic loss in the experimental set-up due to friction in the power-take-off was significant in comparison to the power absorption capability of the model scaled wave energy converter, and consequently, the power absorbed by the wave energy converter was significantly underestimated. To address this major limitation, a simple friction compensation algorithm was tested in the power-take-off control. Experimental results were benchmarked against those obtained from potential wave theory solvers for the understanding of the efficacy of the proposed method. It was evident that the proposed power-take-off control provided high fidelity results under both regular and irregular incident waves as long as the dynamic power-take-off control force was able to overcome the friction force in the experimental set-up.