Vibration energy harvesting using electromagnetic transduction
There has been a growing interest in the field of miniature wireless sensors such as body worn health monitoring sensors, industrial, structural health monitoring and embedded sensors in automotive applications or buildings. Many applications require such sensors to be completely embedded in equipment, structure or clothing with no physical connection to the outside world. As a result, they need to have their own power supply unit. Miniaturization possibilities are offered by using a thin film micro battery; however the device lifetime still depends on its energy storage capacity. Micro generators offer the solution to this problem, adding to microsystems the ability of recharging their energy storage by converting energy from the external environment to electrical power. Within the different forms of energy available, we develop MEMS structures for harvesting mechanical vibrations and movements for the micro and batch fabrication of power generators using electromagnetic transduction. The focus in the Micropower-Nanomagnetics group is at developing novel solutions for miniaturisation and integration of the electromagnetic micropower generator on silicon.
The images below show a micro-fabricated electromagnetic vibration generator developed under the VIBES project. The paddle and beam is fabricated using DRIE etching and a micro-coil is formed on the paddle using electrodeposition. Bulk magnets are placed in a separate Perspex chip holder above and below the coils. The paddle moves under the influence of external vibrations, thus moving the coil relative to the magnets and inducing a voltage in the coil.
DRIE etched paddle and beam with micro-coil Close view of micro-coil Fully assembled micro-generator
Funded Projects/ Grants:
- EU FP6 STREP project - Vibrational Energy Harvesting - 'VIBES' - Recently Finished: http://www.vibes.ecs.soton.ac.uk/
- EU FP 7 Network of Excellence (NoE) - 'NANOFUNCTION'
- EU FP7 FET Flagship project - 'Guardian Angel'
1. Deposition of thick Co-rich CoPtP films with high energy product for magnetic microelectromechanical applications; S. Kulkarni and S. Roy; J. Magn & Mag Mat, 322, 1592-1596, (2010)
2. Self-powered autonomous wireless sensor node using vibration energy harvesting; R. Torah, P. Glynne-Jones, M. Tudor, T. O’Donnell, S. Roy and S. Beeby; Meas. Sci. Technol. 19, 125202 (2008). Editorially selected as one of the journal highlights in the year 2008, which has been made available in a special collection of articles.
3. Wireless sensor system powered by an electromagnetic vibration energy harvester; SP Beeby, RN Torah, MJ Tudor, T O'Donnell, S Roy; Measurement & Control; 41, 4, 109-113, (2008).
4. Design, fabrication and test of integrated micro-scale Vibration based Electromagnetic generator, Santosh Kulkarni, Elena Koukharenko, Russell Torah, John Tudor, Steve Beeby, Terence O’Donnell, Saibal Roy, Sensors & Actuators A: Physical, 145-146, 336-342 (2008).
5. Micro electromagnetic generator for vibration energy harvesting; S P Beeby, M J Tudor, R N Torah, P Glynne-Jones, T O’Donnell, C R Saha and S Roy; J. Micromech. Mcroeng., 17, 1257-1265, (2007). This work recently featured in BBC technology news http://news.bbc.co.uk/2/hi/technology/6272752.stm; Daily Mail; Sunday Telegraph, Times of India and in American radio. Editorially selected as cover article. 540 times cited to date.
6. Experimental comparison of macro and micro scale electromagnetic vibration powered generators: S.P.Beeby, M.J.Tudor, R. N. Torah, S. Roberts, T.O’Donnell, and S.Roy; Microsystem Technologies, 13, 1647-1653, (2007)
7. Development of nano-structured, stress-free Co-rich CoPtP films for magnetic MEMS applications; S. Kulkarni, S. Roy. J. Appl. Phys, 101, 09K524, (2007)
8. Vibration based electromagnetic micropower generator on Silicon; S. Kulkarni, S.Roy, T, O’Donnell, S.Beeby, J. Tudor. J. Appl. Phys, 99, 08P511, (2006); Editorially selected for republication in virtual J. of Nanoscience and Nanotechnology.
9. MEMS vibration powered Electromagnetic generator for wireless sensors applications. E. Koukharenko, S. P. Beeby, M. J. Tudor, N. M. White, T. O’Donnell, C. Saha, S. Kulkarni, S. Roy: Microsys. Technol. 12, 1071, (2006)
Students Graduated (PhD):
1. Santosh Kulkarni
2. Chitta Saha
Dr. Saibal Roy
Head: Micropower Systems and Nanomagnetics
Phone: +353 21 234 6331
e-mail: saibal.roy (at) tyndall.ie