Improving the performance of wind energy galloping harvesting with magnetic coupling

In a realistic environment, the wind speed generally is relatively low, which impedes the further promotion of energy harvesting efficiency. This letter proposes an advanced monostable galloping-based energy harvester (AM-GEH), in which magnetic coupling is introduced to improve harvesting efficiency. By arranging a magnet at the beam tip and three magnets on the arch-shaped fixture, the stiffness of the structure will be softened, which is beneficial for generating large-amplitude deflection for low-speed wind. It is designed so that the middle magnet provides a repulsive force, while the magnets at the two sides provide attractive forces. The combined forces could make the system keep a monostable one, but with a wide flat potential energy. The parameter analysis is carried out to investigate the influence of wind speed and impedance on the output power. For validation, corresponding experiments were carried out. We compare this configuration with the linear galloping-based energy harvester (L-GEH) and the weak-coupled monostable galloping-based energy harvester (WM-GEH). The experimental results show that the cut-in wind speed of AM-GEH is decreased by 55% and 18.2%, respectively, and its RMS voltage is increased by 69.92% and 14.7%, respectively.