Investigating the adaptability of the multi-pump multi-piston power take-off system for a novel wave energy converter

In this work, a numerical model is developed in order to investigate the adaptability of the multi-pump multi-piston power take-off (MP2PTO) system of a novel wave energy converter (WEC). This model is realized in the MATLAB/SIMULINK environment, using the multi-body dynamics solver Multibody™, which is based on the open-source tool WEC-Sim. Furthermore, the hydrodynamic coefficients are calculated using the open-source code NEMOH. After providing the description of the model, it is validated against experimental results and an analytical model, showing good agreement with both. Subsequently, simulations for a single floater device with a multi-piston pump (MPP) unit using our numerical model are carried out to demonstrate the adaptability of the WEC. In addition, the results demonstrate that the MPP with a simple control strategy can extract more energy than any non-adaptable piston pump under various sea states. Finally, a floater blanket (an array of interconnected floaters) model is developed to shed some light on the hydrodynamic response and the performance of MPPs. The developed numerical model will be used in the future to optimize the MP2PTO configuration, and to develop an energy maximization control strategy for the MP2PTO system.