A Bistable Energy Harvester with low base-acceleration and High RMS Output for Train Bogies: Theoretical modeling and experimental validation


 Energy harvesting has provided potential power solutions for distributed sensors in rail transportation condition monitoring. However, the shortcomings of reported harvesters are low efficiency and narrow working bandwidth for scenarios of rail transportation condition monitoring. An energy harvester is developed in this paper has higher energy output efficiency and wider working bandwidth, the harvester is suitable for train monitoring scenarios. The key novelty lies in the combination of spherical moving magnet and cylindrical moving magnet to propose a spherical-cylindrical coupled moving magnet, which not only maintains the advantages of small friction, but also improves energy conversion efficiency. Furthermore, the analytical models are established to describe the dynamics of harvester with different moving magnets (spherical, cylindrical, spherical-cylindrical coupled), and a theoretical framework is established to guide the design. The theoretical model is validated by developed prototypes and experimental results. The working bandwidth of energy harvester with spherical-cylindrical coupled moving magnet is 9.5-45.1 Hz at 2g, output power reaches 18.2 mW at 40 Hz and 1200 Ω load, compared to energy traditional harvesters with cylindrical and spherical moving magnets, the base excitation is lower and the normalized output power is higher. Thus, this energy harvester is more suitable for train monitoring scenarios.