Design and analysis of the piezoelectric-electromagnetic energy harvester based on magnetically coupled structures

This paper proposes a piezoelectric-electromagnetic energy harvester based on magnetic coupling for wind energy harvesting. The prototype utilizes magnetic force between the rotating magnets and fixed magnets to transmit mechanical energy and generate electricity through the piezoelectric energy harvester (PEH) and electromagnetic energy harvester (EMEH) components. The magnetic coupling exerts a non-contact force extending the PZT's lifespan, while the presence of multiple magnets introduces frequency up-conversion, contributing to an increase of the output power. Meanwhile, the rational arrangement of the magnets results in a small start-up wind speed for the harvester. The electromechanical coupling of the wind energy harvester (WEH) is modeled, and the key parameters affecting the characteristics of PEH and EMEH are thoroughly analyzed through experiments and simulations. By synergising the advantages of PEH and EMEH, WEH is capable of effectively charging a 470 μF capacitor to 13.44 V in 50 s.