Experimental assessment of the ifpen solution to the wec control competition

This paper describes the experimental assessment of the solution developed by IFP Energies nouvelles (IFPEN) for the WEC Control Competition (WECCCOMP), a benchmark devised to compare energy-maximizing controllers for wave energy converters (WECs). For the first round of the competition, carried out in simulation with WEC-Sim, IFPEN had submitted an MPCbased solution, which eventually scored best among the contestants, with respect to the energy-related criterion defined by the organizers and computed on a set of six irregular waves. For the second round of the competition, the performance of this MPC solution has been assessed in a tank test situation, on the same Wavestar-like scale device that had been simulated in WEC-Sim. The paper first recalls the features of the control solution implemented for the competition, an offline-tuned weighted-QP MPC algorithm using short-term prediction from present and past wave excitation force estimates. Then, the major steps of the test plan are described and control design choices are explained. Finally, the experimental results in closed loop are presented. Despite noise and an imperfectly controlled PTO actuator, IFPEN's MPC solution proves efficient and robust: Its experimental performance in terms of harvested electrical energy is in accordance with the nominal results obtained in simulation using the linear design model, and this, for different realizations of each sea state. This performance has allowed the IFPEN team to win the competition also at the experimental stage.