Multi-resonant feedback control of a single degree-of-freedom wave energy converter

A method for proportional-derivate complex conjugate control of a wave energy converter, comprising:

• providing a multi-resonant single degree-of-freedom wave energy converter comprising a buoy in a water environment having wave motion, wherein the waves impacting the buoy exert an excitation force with a plurality of excitation frequencies that causes a buoy motion in a heave direction relative to a reference, a sensor for measuring a position or velocity of the buoy relative to the reference for a sample period, a power take-off that is configured to apply a control force in the heave direction to the buoy, and a feedback controller comprising a signal processor;
• measuring the position and velocity of the buoy relative to the reference over a sample period with the sensor;
• extracting a plurality of frequencies, amplitudes, and phases of the measured position or velocity of the buoy using the signal processor,
• computing a proportional-derivative control for each of the plurality of frequencies, amplitudes, and phases;
• adding up each of the proportional-derivative controls to provide a computed control force;
• and
• causing the power take-off to apply the computed control force to the buoy to put the buoy heave motion in resonance with the excitation force.