Floating Oscillating Surge Wave Energy Converter Using Active Controllable Power Takeoff

Background

• Offshore region has larger wave power flux, and less concern on permitting and regulation issues versus nearshore;

• Mooring design is a concern for floating wave energy converters (WECs) due large motion;

• Original submerged on-the-hinge PTO needs huge gearhead ratio to drive generator and has maintenance issue;

• Traditional PTO will lose controllability and has large peak-to-average ratio.

Innovation

• Self-balanced dual-flap design can reduce platform’s horizontal motion and reduce mooring load.

• Above-water self-amplified powertrain can reduce gearhead ratio with high efficiency and reduce maintenance cost.

• Active controllable PTO can enhance system performance and reduce peak-to-average ratio.

Approach

• A system-level co-design method is used to design the overall system cover hydrodynamics, PTO and control;

• A multi-scale synergetic design is adopted to guide the design and make it ready for ocean test;

• A team with university-industry-national lab collaborates together to leverage everyone’s expertise;

• A final design has been checked and validated by American Bureau of Shipping (ABS).

Achievement

• A 1:10 scaled model was tested in wave tank with the max wave-to-wire efficiency of 65%.

• Platform’s horizontal motion can be significantly reduced with slack mooring compared with single-flap.

• Active control can reduce peak-to-average ratio from 14.9 to 7.5.