Enhancing the Bandwidth of a Vibro-impact Cantilever Beam Triboelectric Harvester Using Repulsive Magnetic Nonlinearity

Most energy harvesters are linear, with a restricted frequency bandwidth and poor performance, which prompted the development of nonlinear harvesters with a broader frequency bandwidth. Herein, magnetic nonlinearity is integrated with triboelectric Vibro-impact energy harvesting structures to expand the operational bandwidth and enhance harvesting efficiency at low frequencies. The harvester comprises one cantilever beam that has a magnet attached to its end and is positioned in such a way that the magnet faces another fixed magnet with the same polarity to create a repulsive magnetic force. The beam's tip magnet bottom surface acts as an upper electrode of the triboelectric layer, and when the structure vibrates, it will impact another lower electrode leading to the generation of an electrical signal. The system will vibrate in either a monostable or bistable range by controlling the spacing of the magnets. A single-degree-of-freedom model simulates the dynamic behavior and the generated voltage signals. The harvester's dynamic behavior is evaluated at various separation distances between the two magnets. As a result, higher bandwidth was achieved under the influence of magnetic nonlinearity. Impact-driven triboelectric energy harvesters with induced magnetic nonlinearity can effectively improve efficiency by broadening frequency bandwidth at low frequencies.