Experimental Study of Resonant Frequency Tunable Piezoelectric Energy Harvester

摘要

To improve energy harvesting performance, a resonance frequency tunable piezoelectric (PZT) energy harvester for vibrating applications was presented and investigated experimentally. A piezoelectric vibrational energy harvester (PVEH) consisted of a piezo-cantilever with a permanent magnet at its free-end and another excitation magnet fixed on vibration structure. The two magnets are placed with the same magnetic poles facing each other to produce repulsive force. The cantilever has dimensions of 70×10×0.6 mm~3, clamped 10 mm, and two magnets sized of 10×4 mm~3. The testing results show that the magnetic force, denoted by the initial separated distance between the magnetic dipoles (SDMD), exerts great influence on the generated performance. With the SDMD increasing from 15 mm to 40 mm, the generated voltage rises from 24.4 V to 40 V, and the resonant frequency increases from 33.75 Hz to 38.75 Hz.