Enhanced piezoelectric harvester for track vibration based on tunable broadband resonant methodology

Local vibration energy harvesting promises self-powered monitoring for railway tracks, which can significantly lower the extra costs of labor and maintenance. Random track vibration has distinct broadband characteristics in the frequency domain, resulting in unsatisfactory performance of non-resonant and narrow-band resonant vibration harvesters. To solve the critical issue of insufficient power in piezoelectric harvesters (PEHs), this paper develops a novel piezoelectric cantilever with dual-mass configuration and trimly-tuned broadband for efficiently harvesting track vibration energy. The analytical coupling model of the dual-mass PEH is firstly created, followed by the electromechanical model of the coupled vehicle-track-harvester system that studies the track vibration characteristics and evaluates the output of PEH. Our PEHs adopting tunable broadband resonant methodology and having arbitrary geometric parameters enable their first two natural frequencies to match those of track excitations, which significantly enhances the energy harvesting capability particularly in the high-frequency domain. In field tests, the voltage peaks of our PEH can reach up to 6 times those of conventional one in time domain under pulse excitations, which validates the superiority of our developed PEHs and potentially unlocks its practical applications in railway.