Design, modeling, characterization and analysis of a low frequency micro-fabricated piezoelectric cantilever for vibration sensing and energy harvesting applications

Abstract

The technological advances in electronics have enabled the development of low-power devices with miniaturized sensors that can be used in a wide range of monitoring applications. Research into alternative solutions for powering these devices has led to the study of vibration energy harvesters, of which, the piezoelectric micro-cantilevers are of interest. This paper provides a comprehensive study of a MEMS based micro-cantilever, containing a thin film of Aluminum Nitride used as a piezoelectric material to harvest and sense vibrational energy. The proposed device was designed with a very low resonance frequency of 163 Hz to adequately match the high energy harmonics found in common sources of ambient vibrations. An overview, design and simulation of an integrated MOSFET based rectifier, optimized to enable the energy harvesting and vibration sensing application is presented. A preliminary simulation of the micro-cantilever device is conducted to estimate its power output, and a low budget experimental setup is developed to characterize the device. A power output of 0.491 μW was measured at the resonance frequency of 163 Hz for a vibration intensity of 10 m s−2, and a new semi-empirical model was proposed, which showed only a 1% deviation from that measured peak value. Using an appropriate metric, the performance of the device was compared with similar state-of-art devices reported by other authors. Lastly, a brief applicability discussion is provided, analyzing the potential of the studied device to be used as an energy harvester for low-power electronics and as a vibration sensor.