Frequency up-converted wide bandwidth piezoelectric energy harvester using mechanical impact

This paper presents an impact based frequency up-converted wide bandwidth piezoelectric energy harvester in which two high frequency piezoelectric generating beams are struck at the same time by a low frequency driving beam having horizontally extended tip mass. Change of driving beam's effective stiffness during coupled vibration after impact allows the device to broaden the -3dB bandwidth to approximately 170% and to acquire more than 61% of the maximum power generation in the vicinity (from 7 to 10.5 Hz) of the -3 dB bandwidth region as well. The efficiency of electrical power transfer is increased to approximately 85%. Each generating beam produces 377 mu W peak power at 14.5 Hz under 0.6 g acceleration with corresponding power density 58.8 mu W cm(-3). (C) 2013 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.