On the optimal performance of oscillating surge wave energy converter

The sequential process is a conventional procedure in designing an ocean wave energy converter, from mechanical systems to electrical loading. However, many studies do not consider the reciprocal influences between the two domains. Therefore, the potential of a wave energy converter has not been properly explored. In this paper, the performance of an oscillating surge wave energy converter driven by regular wave excitation is investigated, in which the dynamics of subsystems and their couplings are fully taken into account. We analytically determine the maximum possible power that can be harvested for a specific geometry of the wave capture structure. We further show that these geometric dimensions and the rest of the system can be optimized within a unified framework to maximize the output power under given ocean wave characteristics. The upper bound on power is expressed as a function of an effective figure of merit for the power take-off of the wave energy converter, a dimensionless parameter that quantifies the coupling strength of the electromagnetic transducer relative to the electrical parasitic losses and mechanical transmission damping. We further consider practical limitations where ideal conditions, such as attaining resonance, may not be feasible. For both ideal and non-ideal cases, we derive analytical solutions to system parameters, including the resistive and reactive elements of complex electrical loads, mechanical transmission, and generator moment of inertia. In order to verify the analytical derivations, we implement an equivalent circuit model in a dynamic simulator, achieving nearly identical results between simulations and analytical theory. These findings provide a comprehensive framework for optimizing the performance of an oscillating surge wave energy converter and similar architectures.