Electrical damping of linear generators for wave energy converters—A review

The electrical damping of point-absorber wave energy converters is crucial to optimize the power output. Many circuit topologies have been proposed, but the possible increase in power absorption must be weighed against parameters such as cost, reliability and control system complexity. In this paper, the known electrical damping circuits are categorized, described and compared. The hydrodynamic damping of the buoy is covered, and how a linear generator can be used as a power take-off unit to apply a damping force. A qualitative comparison of the circuits is presented in the end. A more complex and costly power electronics system may be viable for wave energy converters (WECs) of large-scale power rating. However, for farm operation with small-scale WECs, a simpler and passive damping may be more suitable.