In this thesis a model predictive control scheme of a discrete displacement hydraulic power take-off system is developed. The thesis takes offset in the Wave Star wave energy converter for which a discrete fluid power power take-off system has been proposed. No optimal control structure of such system has yet been developed, why this work investigates the potential of model predictive control. A model of the PTO system is developed and validated by measurements performed on a hydraulic test bench. A model predictive control scheme maximising the harvested energy of the system including system losses is formulated. The control scheme requires a discrete optimisation problem to be solved in real time. Differential evolution is used as optimisation solver and is modified to fit the discrete optimisation problem and effort in lowering the computational time has been done by model simplifications and loss approximation.
The proposed control scheme is implemented on the test bench and is compared to previous developed reactive control scheme. Tests show that the developed model predictive control may be implemented and executed in real time. Tests performed on the test bench suggest that the model predictive control scheme can outperform the reactive control scheme with respect to the average harvested power from the ocean waves.