One of several challenges that wave energy technologies face is their inability to generate electricity
cost-competitively with other grid-scale energy generation
sources. Several studies have identified two approaches
to lower the levelized cost of electricity: reduce the cost
over the device’s lifetime or increase its overall electrical energy production. Several advanced control strategies have been developed to address the latter. However,
only a few take into account the overall efficiency of the
power take-off (PTO) system, and none of them solve the
optimization problem that arises at each sampling time on
real-time. In this paper, a detailed Nonlinear model predictive control (NMPC) approach based on the real-time
iteration (RTI) scheme is presented, and the controller performance is evaluated using a time-domain hydrodynamics
model (WEC-Sim). The proposed control law incorporates
the PTO system’s efficiency in a control law to maximize the
energy extracted. The study also revealed that RTI-NMPC
clearly outperforms a simple resistive controller.
