Co-design Investigation and Optimization of an Oscillating-Surge Wave Energy Converter

Ocean wave energy has the potential to play a crucial role in the shift to renewable energy. In order to improve wave energy conversion techniques, a recognition of the sub-optimal nature of traditional sequential design processes due to the interconnectedness of subsystems such as the geometry, power take-off, and controls is necessary. A codesign optimization in this paper seeks to include effects of all subsystems within one optimization loop in order to reach a fully optimal design for an oscillating-surge wave energy converter. A width and height sweep serves as a brute force geometry optimization while optimizing the power take-off components and controls using a pseudo-spectral method for each geometry. An investigation of electrical power and mechanical power maximization also outlines the contrasting nature of the two objectives to illustrate electrical power maximization's importance for identifying optimality. The codesign optimization leads to an optimal design with a width of 12 m and a height of 10 m. The power take-off and controls systems are also examined more in depth to identify important areas for increased focus during detailed design. Ultimately, the codesign optimization leads to a 61.4% increase in the objective function over the optimal design from a sequential design process while also requiring about half the power take-off torque.