A Nonlinear Generalized Predictive Control Scheme for the Oscillating Water Column Plants

Under unknown waves, the efficiency of the wave energy conversion systems can be improved by applying a novel control algorithm that is able to anticipate the behavior of the plant. In this paper, a generalized predictive control scheme for wave power generation systems that includes a Wells turbine and an induction generator is proposed. The main idea is to maintain the flow coefficient at its optimal point for generated power maximization and, at the same time, improve the efficiency of the Wells turbine and avoid the stalling phenomenon by means of regulating the turbine rotational speed. Moreover, by using the capabilities of the predictive controller, the limitations of the stator current and the effect of the mechanical dead time of the system are integrated into the regulator design process, as well as the flux weakening technique. Simulation and experimental results, through a test bench that has been designed and constructed, show the validity and capability of the proposed scheme in both the rated and flux weakening regimes.