Piezomagnetic cantilever stator energy harvester using Savonius wind rotor

Abstract

This paper proposes the piezomagnetic cantilever beam energy harvester connected to the Savonius vertical axis wind turbine for micro-power generation. The system consists of a rotor plate that is driven by the vertical shaft of the turbine and a stator with a vertically installed piezoelectric cantilever beam. Several magnets are mounted on the rotor and one magnet is attached at the free end of the cantilever as a tip mass. The alternating magnetic interaction force between magnets on the stator and the rotor induces deflection and strain on the piezoelectric layer that generates power. The arrangement of the magnets, wind speed, and resistive loads are some parameters that play important roles in the output power that are relatively investigated by experiments with the same conditions. Based on experimental results, by increasing resistive load, output power increases and then decreases. The same trend was observed for the gap distance between magnets mounted on the rotor and the stator. The 11 mm gap, 60 mm distance from the center, and 33 kΩ were obtained for the arrangement of the magnets on the rotor and also resistive load which leads to the highest power density of 0.85 μWcm-2 at 9.5 m/s wind speed using the standard circuit. Adding a second piezoelectric cantilever causes 37% (1.17 μWcm-2) and 80% (1.54 μWcm-2) improvement in the output power compared to single piezoelectric for series and parallel electrical connection respectively.