| description abstract | Abstract. The increasing demand for sustainable energy has driven advancements in hydrofoil-based marine energy converters. In this study, a 1 kW-scale hydrokinetic converter with a dual-hydrofoil configuration is modeled and optimized to maximize net electrical output under periodic flow conditions. A dynamic model is developed using the Euler–Lagrange formulation, and a control co-design optimization is performed by simultaneously tuning three design variables—maximum pitch angle, pitch profile shape parameter, and spring stiffness—alongside the generator torque trajectory. The final time of the simulation is also treated as an optimization variable, effectively capturing the oscillation period of the system. Time-domain simulations at a flow velocity of 1.5 m/s show that the hydrofoil completes an oscillation cycle in approximately 1.7 s, achieving a net electrical output of about 1 kW and an overall power train efficiency of approximately 59%. To evaluate the impact of different optimization goals, we compare designs optimized for mechanical power, electrical power excluding pitch motor losses, and net electrical power including those losses. The results show that ignoring actuator energy consumption leads to lower overall efficiency, emphasizing the need to incorporate it into the optimization. Sensitivity analyses further reveal the strong coupling between design variables, underscoring the value of co-optimization. The results provide practical guidelines for designing efficient hydrofoil-based energy harvesters for real-world marine applications. | |
