Rotational Speed Control of an OWC Wave Power Plant

Abstract

The paper deals with the control of an oscillating water column wave energy plant, equipped with a Wells turbine driving a variable speed electric generator. The control of the plant is achieved by changing the electric torque through the power conditioning equipment. The control has to meet several requirements: rotational speed allowable range, energy quality, and allowable fluctuations in power delivered to the grid. On the other hand, the turbine is expected to perform efficiently, and so its rotational speed should approximately match the sea conditions (it should be higher in more energetic sea states). Three different control strategies are described. Results of numerical simulations are presented for two of them, and are found to satisfy the prescribed requirements.