Perspectives on Damping Strategy for Heaving Wave Energy Converters

Damping strategies are cost-effective and easy-to-implement, and are used to mechanically load heaving wave energy converters (WECs) by utilizing the combination of a properly sized power takeoff (PTO) system and an accompanying control algorithm. Compared with reactive-based control strategies, damping strategies have lower energy throughput, but they can be effective for small WEC systems. To the best of our knowledge, damping strategies have been generally discussed either within the mechanical or the electrical framework. Therefore, this paper is an attempt to bridge the two directly interacting sides of the problem. Furthermore, the effect of the wave characteristics and the operating conditions of the PTO system on the power capturing performance of WECs is examined. A criterion to properly select the required damping, considering not only the hydrodynamic forces but also the limitations present in the PTO system, is proposed. The simulation and experimental results of the investigated system are provided and discussed.