Numerical investigation of adaptive damping control for raft-type wave energy converters

Abstract

This paper aims to study the hydrodynamic characteristics and power generation capacity of raft-type WEC (Wave Energy Converter), and to investigate the feasibility of adaptive damping control for this kind of WEC. The numerical model of Pelamis WEC is built in software ANSYS-AQWA. By calling external force and power routines at each time step to calculate the torque and power generated by the generation system and back to the software, the time domain numerical simulation of Pelamis WEC's hydrodynamic response and power generation capacity is realized. Then the numerical simulation of adaptive damping is realized by defining the damping as a function of wave parameters, where the wave parameters are required to be forecasted and is computed in MathWorks Simulink based on the auto regression and Fourier transform methods. Then the hydrodynamic response and power generation performance of the Pelamis WEC under different stiffness and damping (constant) and adaptive damping conditions are calculated. Results show that the power generation capacity of the Pelamis WEC can be promoted by more than 15.9% with the adaptive damping control strategy based on the wave parameters. However, it is still limited to some factors, especially the wave forecasting method.