Abstract
A multidisciplinary perspective is necessitated for the analysis of wave energy conversion systems, spanning hydrodynamics, mechanics, electric power, and control systems. The complexity inherent in these scientific domains poses challenges for unified analysis. This paper addresses these challenges by connecting various domains through the application of circuit theory, characterizing the multiphysics system as an equivalent circuit. The methodology is exemplified using the two-body Reference Model 3 (RM3) Wave Energy Converter (WEC). Initially, equations of motion for each body are formulated, encompassing all six degrees of freedom, resulting in a model with 12 degrees of freedom. Subsequently, selective Eigenmode approximation analysis is employed to reduce the model to two modes, visualized as an equivalent circuit. Simulation results facilitate the comparison between the equivalent circuit model and the original full-order model. Furthermore, to enhance the accuracy of WEC modeling and overcome limitations in analogies between mechanical and electrical components, this paper introduces Instantaneous Frequency Modeling (IFM). Improved modeling accuracy and the facilitation of testing various control methods are achieved through IFM. Leveraging the principle of electrical resonance, specifically impedance matching, enables the optimization of wave energy harvesting by controlling the force on the power take-off unit. Simulation results from the instantaneous model are presented, and performance under diverse control techniques is investigated.