Piezoelectric Energy Harvester

The resonance frequency of a MEMS structure is usually quite high compared to the frequencies of the environmental vibrational sources. A mass was loaded at the centre of the in-plane poled piezoelectric diaphragm to lower its resonance.

A receptance model is built to explain the resoance of the diaphragm-mass combined system. The receptance model is an approach used to predict the vibrational characteristics of a combined system from the characteristics of indiviual components.

The optimized working condition of the diaphragm was tested. The diaphragm-based energy harvester shows the maximum power when it works at its anti-resonance and the load impedance matches the output impedance of the piezoelectric diaphragm.

The resonance drop very fast with little mass and the drop rate becomes slow with bigger mass. The resonance frequency change predicted by the receptance model agrees with the measured results.

The voltage and power received by the energy harvester crossing the optimized load versus acceleration. A power density of 22.59 μW/cm² was realized.

The research opens the way to making use of combined system dynamics to control the vibration of piezoelectric MEMS energy harvesters.

For more information, please refer to:

[1], Zhiyuan Shen, Shuwei Liu, Jingyu Lu, Jianmin Miao, Lye Sun Who, Zhihong Wang, “Spiral electrode d33 mode piezoelectric diaphragm combined with proof mass as energy harvester”, Journal of Micromechanics and Microengineering，25，(2015), pp. 035004.

[2], Zhiyuan Shen, Shuwei Liu, Jianmin Miao, Lye Sun Woh and Zhihong Wang, “Proof mass effects on spiral electrode d33 mode piezoelectric diaphragm-based energy harvester”, IEEE MEMS 2013, January, (2013), Taipei.

[3], Zhiyuan Shen, Shuwei Liu, Haobing Liu, Kottapalli Ajay Giri Prakash, Jianmin Miao, Lye Sun Woh, “Piezoelectric d33 mode diaphragm energy harvester for self-powered sensor application”, IEEE Sensors, October, (2012), Taipei.