Eric Yeatman
Imperial College London

Kinetic Energy Harvesting: Rotating Systems

Driven by advances in microelectronics, sensors, and radio technology, highly miniature, low cost wireless devices are proliferating rapidly in a wide range of applications. This is enabling the distribution of sensing capability throughout household, urban and other environments (pervasive sensing), as well as the enhancement of previously passive artefacts with intelligence and connectivity (the Internet of Things).
These technologies offer major benefits, including enhanced energy efficiency, system resilience and adaptability, and the provision of new functions and services for users. However, adoption is significantly impeded by the maintenance burden of replacing or recharging huge numbers of batteries.
Energy harvesting - the collection of otherwise unexploited energy in the local environment - is attracting increasing attention as a solution to this problem.
Kinetic energy harvesting - the extraction of power from ambient motion and vibration - has been explored by a large number of researchers, and many devices have been demonstrated. Most, particularly in the micro-scale, use oscillating internal motion; this avoids the need for bearings, but restricts the internal motion range. This talk will focus on micro-engineered devices for kinetic energy harvesting using rotating mechanisms, powered by random vibrations such as human body motion, or by fluid flow. It will be shown that piezoelectric transduction can be employed in such devices, and that this can give significant advantages over electromagnetic devices in terms of device cost and complexity, operating frequency range, and scaling. New scaling laws for these systems will be presented, as well as a number of practical devices for different applications.