Experimental Methodology for Power Generation Assessment of a Point-Absorber Wave Energy Converter Based on a Small-Scale Model

Abstract Assessing the power generation performance of wave energy converters (WECs) through wave basin experiments using small-scale models presents considerable challenges. Scaling down introduces difficulties in integrating generators and relatively increases energy losses from wave absorption to electric energy generation. For point-absorber WECs (PA-WECs), both the approximate complex-conjugate control considering copper loss (ACL) to maximize net generated power, and Artificial Intelligence (AI)-based practical strategies to enhance power generation, have been studied numerically, however, experimental validation remains limited. This study proposes an experimental methodology to predict the power generation performance of a PA-WEC, focusing on control force estimation using a 1/102.1 scale model. The approach involves measuring forces on the float under diffraction tests (DTs) and two forced oscillation scenarios. These forced oscillation tests (FOTs) are conducted in the same regular wave conditions as the DTs. First, the input oscillations for FOTs are derived by solving the equation of heave motion with zero control force. Next, FOTs are performed using input oscillations obtained by solving the equation with non-zero control force. Based on the measured forces, control force is estimated. Finally, net generated power is calculated as the product of the estimated control force and heave velocity, with copper loss subtracted. This study also explores the sensitivity of net generated power to variations in input heave phase and amplitude, providing valuable insights into improving the power generation performance of a PA-WEC.