Optimal Configuration of Discrete Fluid Power Force System Utilised in the PTO for WECs

In the pursue of lowering the cost of energy for ocean wave energy devices the energy conversion efficiency of the Power Take Off (PTO) system has attained increased focus. A discrete fluid power force system has been proposed as a possible solution to improve the conversion efficiency. Transferring from a continuous fluid power PTO-system to a discrete poses the question of configuration and control of the discrete fluid power system utilised in a wave energy converter (WEC).

The current paper presents a method for determining the optimal configuration of a discrete fluid power force system for the PTO-system in a WEC. A model based optimisation is utilised to identify the system configuration leading to the highest energy output. It is shown how the time distribution of wave conditions affects the choice of system configuration. Based on the current paper the preferred PTO system configuration consists of a two chamber cylinder and three common pressure lines in the tested sea conditions.