Design And Characterization On Piezoelectric Cantilever As A Self-Powered Accelerometer

Piezoelectric cantilever working on direct piezoelectric effect has shown promising applications as a sensor as well as a micro-power generator depending on the amount of stress that is applied on the piezoelectric material at different range of frequencies. In this research, a self-powered accelerometer that consists of a wide-band energy harvesting power generator, a low operating frequency device acceleration sensor, and a signal conditioning circuit is designed. Piezoelectric cantilevers are being used in this research as a sensor to measure the vibration acceleration level and at the same time as a generator to power up the amplifier circuit. This research includes characterize the frequency response of the piezoelectric cantilever by altering its effective mass and length, design the selfpowered accelerometer system, and lastly verify the output of the self-powered system with battery powered system. The result shows that increasing the effective mass of the cantilever can reduce the resonant frequency of the cantilever, while reducing the effective length of the cantilever would increase the resonant frequency. The designed self-powered accelerometer is able to operate at broadened operating frequency range of 180-310 Hz with acceleration level of not lower than 0.8-g and is able to produce linear output with a sensitivity of 231.28mV/g-level. The piezoelectric generator is able to produced constant voltage output of 1.8V and power output not less than 80μW at operating condition. While for the sensor, signal is successfully amplified at a factor of 3.2 with error deviation less than 15%. The overall result is verified and shows good agreement of 5% error with conventional battery powered accelerometer system and compatible with standard vibration source

Broadband Energy Harvesting using Multi-Cantilever based Piezoelectric

Wideband energy harvesting is essential particularly for extracting electrical energy from ambient vibration which is random. Researches show that the frequency bandwidth of the harvested energy can be effectively enhanced by using multiple cantilevers with different resonant frequencies connecting together. This paper investigates the effect of the different electrical configurations towards the output of the piezoelectric array. An array of four similar piezoelectric cantilevers was mounted side-by-side to operate as a system in generating electrical output across frequencies range up to 500 Hz. The resonant frequency of each of the cantilever was varied by introducing a proof mass of 0.15g, 0.50g and 1.00g at the tip of the cantilever. The result shows improvement in the frequency bandwidth of the piezoelectric array, where it is widened to 150 Hz with improved gap when connected in alternating polarities configurations. The piezoelectric array produces higher voltage when connecting in series configuration; but higher power when connecting in parallel configuration

Demonstration of Self-Powered Accelerometer Using Piezoelectric Micro-Power Generator

This paper demonstrates the operation of a self-power vibration measurement system. A piezoelectric material in the form of a cantilever is being used as a generator which harvest energy from ambient vibration source and transform into useful electrical output. The vibration sources is measured with a MEMS based accelerometer, which is powered up by the transformation of electrical energy derived from the mechanical vibration source itself. It has shown that at a resonant frequency of 78 Hz with an acceleration level of 1g (9.81 m/s2), the piezoelectric generator is able to produce rms output voltage of 5.20 V and successfully operating ADXL335 with the assistance of energy harvesting conditioning IC, LTC3588-1 equipped with rectifying as well as DC-to-DC step-down functions

Investigation On Phase Shifting Effect On The Voltage Output Of Piezoelectric Cantilever Array

This paper analyses the phase shifting of the output waveform produced by piezoelectric cantilevers under a range of vibration frequencies. The phase shift of four piezoelectric cantilevers with different resonant frequency are inspected while it is excited with the vibration from the electrodynamics shaker at a range of frequencies from 100 Hz to 500 Hz with the acceleration level (g-force) fixed at constant magnitude of 1g-level (9.81 m/s2). Time different and Lissajous pattern methods were used in this research to measure the phase shift of the output waveform. Both methods show similar result where the major phase shift happened at the resonant frequency of respective cantilevers. The phase difference remains low around 0 degrees or in other term in phase before the resonant frequency of the cantilever. When the frequency of the vibration source approaches the resonant frequency of respective cantilever, the phase different start to increase rapidly and reach 180 degree which is out of phase after the resonant frequency. This major phase shifting contributes to the significant rise of the gap in between the peaks formed when multiple piezoelectric cantilevers are connected together. As a result, it indirectly improves the output performance of the piezoelectric cantilevers array

Parametric Studies on Resonance Frequency Variation for Piezoelectric Energy Harvesting With Varying Proof Mass and Cantilever Length

This paper demonstrates the potential of the resonance frequency for a piezoelectric beam clamped on one of its end to be altered to a higher or lower range by introducing additional proof mass or by reducing the piezoelectric cantilever length. When the effective mass of the cantilever is increased, the resonance frequency of the cantilever is expected to shift to lower region, while when the stiffness of the cantilever is increased, the resonance frequency of the cantilever is expected to shift to higher region. These statements have been proven and validated in this paper. Overall, the experimental result showed good agreement with the theoretical result, however, there was still 20% and 35% error different for the proof mass experiment and length reduction experiment respectively

Power Optimization Configuration For Piezoelectric Cantilever Arrays

This paper investigates the changes in the output of the piezoelectric cantilever arrays when connected in different configurations. In this research matching load resistance determined and optimum output was measured by connecting the piezoelectric cantilever arrays to resistance ranging from 10 Ω to 1 MΩ while excited by constant vibration source at frequency of 300 Hz and acceleration of 1-g level. The result shows that matching load resistance for one single piezoelectric cantilever is 13 KΩ. When two, three and four cantilevers are connected in series, the matching load resistance is 26 kΩ, 39 kΩ and 52 kΩ respectively. While in parallel connection, matching load resistance reduced to 6.5 kΩ, 4.5 kΩ and 3.5 kΩ for two, three, and four connected cantilevers respectively. In series configuration, the voltage output produced is much higher as compared to the piezoelectric cantilever arrays that are connected in parallel connection. The voltage output of the piezoelectric cantilever increased from 3.41V to 6.09V when it is connected in series configuration with same polarity. Whereas in term of power output, piezoelectric cantilever arrays in parallel configuration produce higher power output as compared to piezoelectric cantilever arrays in series connection. The maximum power increased from 272μW to 521μW when two cantilevers are connected in parallel configuration with same polarity

Implicating genes, pleiotropy, and sexual dimorphism at blood lipid loci through multi-ancestry meta-analysis

Publisher Copyright: © 2022, The Author(s).Background: Genetic variants within nearly 1000 loci are known to contribute to modulation of blood lipid levels. However, the biological pathways underlying these associations are frequently unknown, limiting understanding of these findings and hindering downstream translational efforts such as drug target discovery. Results: To expand our understanding of the underlying biological pathways and mechanisms controlling blood lipid levels, we leverage a large multi-ancestry meta-analysis (N = 1,654,960) of blood lipids to prioritize putative causal genes for 2286 lipid associations using six gene prediction approaches. Using phenome-wide association (PheWAS) scans, we identify relationships of genetically predicted lipid levels to other diseases and conditions. We confirm known pleiotropic associations with cardiovascular phenotypes and determine novel associations, notably with cholelithiasis risk. We perform sex-stratified GWAS meta-analysis of lipid levels and show that 3–5% of autosomal lipid-associated loci demonstrate sex-biased effects. Finally, we report 21 novel lipid loci identified on the X chromosome. Many of the sex-biased autosomal and X chromosome lipid loci show pleiotropic associations with sex hormones, emphasizing the role of hormone regulation in lipid metabolism. Conclusions: Taken together, our findings provide insights into the biological mechanisms through which associated variants lead to altered lipid levels and potentially cardiovascular disease risk.Peer reviewe