Study on model predictive control for the wave energy converter with a linear generator

Some active controls were proposed to maximize the power production for the point absorber type wave energy converter (WEC) with a linear generator. However, proposed conventional controls have some problems, e.g. constraint conditions cannot be considered. Model predictive control (MPC) has attracted attention as an alternative method to solve these problems. In this paper, the performance of the MPC for the WEC with the linear generator was evaluated by experiments and numerical simulations. In the experiments in regular waves, the MPC performance was comparable to the conventional control of the power production amount reasonably. Furthermore, the MPC was more effective than the conventional control in irregular waves which has broadband spectral distribution. The numerical simulations in the irregular waves analyzed three characteristics of the proposed MPC. Firstly, it was investigated how much the power production decreased due to wave predictive error. Secondly, the best predictive horizon of the proposed MPC was investigated. The simulation result showed the predictive horizon of the MPC needs to be longer than the averaged wave period in irregular waves. Finally, performance of the MPC was compared with that of the conventional control under displacement constraints. It was confirmed the MPC presented in this paper was more effective than the conventional control under the displacement constraints.