Wave Energy Converter Optimization with Multi-Resonance Controller of the Electrical Power Take-off

Abstract

The world’s oceans hold a tremendous amount of energy and are a promising resource of renewable energy. Wave Energy Converters (WECs) are a technology being developed to extract the energy from the ocean efficiently and economically. The main components of a WEC include a buoy, an electric machine, an energy storage system, and a connection to the onshore grid. Since the absorption of the energy in the ocean’s waves is a complex hydrodynamic process a power-take-off (PTO) mechanism must be used to convert the mechanical motion of the buoy into usable electric energy. This conversion can be done by using a rack-and-pinion gear system to transform the linear velocity of the buoy into a rotational velocity that is used to turn the electric machine. To extract the most energy from the ocean waves a controller must be implemented on the electric machine to make the buoy resonate with the frequency of the waves. For irregular wave climates a multi-resonance controller can be utilized to resonate with the wave spectrum and optimize the power output of the WEC.