Design guidelines for optimization of an inertially coupled energy harvesting generator from boat motion

This paper proposes a set of guideline for optimum design of an energy harvester from the vertical motion of small boats and yachts. The device comprises a sprung mass coupled to an electrical generator using a ball screw. The mathematical equations describing the dynamics of the system are derived. The equations are used as a basis for determining the optimum device parameters, namely, its mass, spring stiffness, ball screw lead, and load resistance. The process of design optimization is presented as an integrated part of the design guidelines, to maximize the system output power and efficiency within practical constraints. In addition, the experimental results of testing a ball screw based energy harvester are presented. The main purpose of conducting the experiment is to observe the performance of the system and validate the dynamic equations of the system. The experimental results that investigate the frequency response, relation between base and relative displacements and the output power profile are in reasonable agreement with the theoretical calculations.