An Energy-Maximising MPC Solution to the WEC Control Competition

Abstract

The WEC Control Competition is a benchmark devised to compare energy-maximising controllers for wave energy converters, first in simulation, then in real time, using a scale device in a tank test situation. For the first round of the competition, the evaluators have provided a model of a leg of a Wavestar-like device, in the WEC-Sim simulation environment. The evaluation is based on an energy-related criterion computed on six irregular waves. IFPEN’s solution is an energy-maximising model predictive control (MPC), composed of an estimation algorithm for wave excitation force moment, using measurements (or estimations) of float displacement and velocity and PTO moment; an algorithm for short-term wave force prediction from present and past wave excitation force estimates, where no information about wave elevation is used; a real-time compatible MPC algorithm using wave force prediction, which maximises the average produced electric energy, taking into account the nonlinear PTO efficiency law.