THE DYNAMIC MECHANISM OF HEAVE IN OSCILLATING BUOY-TYPE WAVE ENERGY DEVICES AND THE OPTIMIZATION OF ENERGY HARVESTING SYSTEMS

Abstract

This paper presents a systematic study on dynamic modeling and parameter optimization to address the energy capture efficiency of wave energy conversion devices in the vertical oscillation mode. Based on Newton’s second law, the study establishes a coupled second-order nonlinear differential equation system describing the motion of the float and the embedded oscillator, comprehensively considering the interactions among wave excitation forces, wave-induced damping forces, hydrostatic restoring forces, and the energy output system. To solve this strongly coupled system of equations, the fourth-order Runge-Kutta method was employed to calculate time-domain responses, yielding precise dynamic characteristics of system displacement and velocity at extremely small time steps. For evaluating energy conversion efficiency, a single-objective optimization model was formulated to maximize steady-state average output power, utilizing Riemann integration and approximation methods to handle the discretized integration of instantaneous power. By introducing a Bayesian optimization algorithm, the study achieved efficient heuristic search within the complex damping parameter space. Experimental results show that under two typical operating conditions—constant damping and power-law damping—the system achieved the expected power capture targets through optimal damping coefficient configuration, with a maximum average power of 228W. These findings provide quantitative evidence for the structural optimization of wave energy devices and the formulation of PTO system strategies.