Piezoelectric Pressure Energy Harvesters Using Circular Diaphragms With Concentric Ring-Boss Structures

Abstract

This paper describes the design, fabrication and testing results of aluminum nitride piezoelectric micromachined circular diaphragm energy harvesters with concentric ring-boss structures to convert pulsed pressure to electrical power with high efficiency. Compared to the state-of-the-art, the concentric-ring-boss harvesters (CRBH) produce multiple strained regions for: (1) more effective electrode areas; (2) high charge extraction rates; and (3) high power outputs. Finite element modeling is used to evaluate the effectiveness of the proposed design by comparing stress and stretching energy of various designs. The conventional single-boss and concentric ring-boss harvesters have been fabricated and tested under a mean pressure of 1.5 kPa with 1 kHz frequency. Experimental results show the ring-boss and the conventional single-boss harvesters can generate power of 1.3 and 0.82 μW, respectively. As such, the CRBH is 1.6X higher in energy conversion efficiency and power density as compared to single-boss design of similar dimensions.

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“…The disadvantage of using a single boss structure is that the area on top of the boss itself becomes a zero-strain region, thus making this area useless and impossible to generate charge from there and contribute to power generation. Previously, our group proposed a design that has concentric ring and boss structures and has potential to increase the efficiency of the output power but for relatively higher operation frequency (Beker et al 2016). In this study, we focused on a similar design where concentric ring and boss structures are utilized to increase strained regions on the diaphragm to enhance charge extraction rate from the piezoelectric material.…”