Novel contactless axial-flux permanent-magnet electromechanical energy harvester

This paper proposes a novel type of watt-range permanent-magnet energy harvester, which harvests energy from a moving conductive body or surface without mechanical contact, as its operation is purely based on eddy-current coupling. The harvester's main advantage over existing solutions is that it allows energy transfer over atypically large (2 ... 15 mm) air gaps, which are unavoidable in certain industrial applications. The paper provides a detailed description of the system's operating principle, and elaborates its modeling using 3-D Finite-Element Method (FEM) analysis. Two prototypes are built and tested for verifying the models. A power of 2.42W is harvested from an aluminum surface moving with 10 m/s, over 12mm air gap using a prototype with ≈ 14 cm
³
magnet volume. Moreover, the effects of the harvester's placement as well as the speed of the moving conductive surface on the maximum harvested power and the system's efficiency are analyzed, both with FEM simulations and measurements.