Title: An energy harvester from human vibrational kinetic energy for wearable biomedical devices
Author: Jiayang Song; Kean C. Aw
Address: Mechanical Engineering, The University of Auckland, 20 Symonds Street, Auckland, New Zealand ' Mechanical Engineering, The University of Auckland, 20 Symonds Street, Auckland, New Zealand
Journal: Int. J. of Biomechatronics and Biomedical Robotics, 2014 Vol.3, No.1, pp.54 - 61
Abstract: An electromagnetic kinetic energy harvester has been a topic of considerable interest over recent decades because it is suitable for harvesting human's kinetic energy at low frequency with the high power density. A small, wearable and portable electromagnetic energy harvester was developed and aimed at applications such as extending the operating period of bio-medical devices through constant charging of batteries. The proposed harvester consists of a snake-shape polydimethylsiloxane cantilever, a coil and an NdFeB magnet enclosed in a polymer casing. Its resonant frequency is ~6.6 Hz and the peak-to-peak output voltage is ∼10 mV when tested on a shaker with an acceleration of 0.3 g. When tested at 1.5 g to mimic the acceleration when a person walks, the peak-to-peak output voltage is ~40 mVpp. An unconventional method of voltage rectification has been demonstrated using the combination of a miniature transformer and capacitors to produce unipolar pulses that can be used to trickle charge a battery. Although still not a perfect rectification, nevertheless this method has the potential to replace a diode in the standard rectifier.
Keywords: energy harvester; low frequency; vibration kinetic energy; human motion; wearable devices; biomedical devices; electromagnetic kinetic energy; voltage rectification; battery charging.