Control Co-Design of Mechanical Power Takeoff for a Dual-flap Surge Wave Energy Converter

This paper presents a control co-design method for designing mechanical power takeoff (PTO) systems of wave energy converters. A dual-flap oscillating surge wave energy converter is selected to carry out the two degrees of freedom co-design investigation. Unlike most existing work's simplified representation of harvested power, this paper derives a more realistic electrical power representation based on a concise PTO modelling. This electrical power is used as the objective for PTO design optimization with energy maximization control also taken into consideration to enable a more comprehensive design evaluation. A simple PI control structure speeds up the simultaneous co-optimization of control and PTO parameters, and an equivalent circuit model of the WEC not only streamlines power representation but also facilitates more insightful evaluation of the optimization results. The optimized PTO shows a large improvement in terms of power potential and actual power performance. It's found the generator's parameters have the most influences on the power increase.