Anahita Zargarani

Bio: Anahita Zargarani is an academic researcher from University of Alabama. The author has contributed to research in topics: Energy harvesting & Cantilever. The author has an hindex of 2, co-authored 5 publications receiving 8 citations.

Circuit Optimization for Enhancing the Output Power of a Piezoelectric Energy Harvester

Abstract: In this paper, a new method is proposed for improving a piezoelectric energy harvester’s output power. A piezoelectric vibration energy harvester has an inherent internal capacitance. The new approach adopts inductance to reduce the reactance of the internal capacitance and enhance the output power. To show the practicality of this method, four electrical circuits are investigated numerically and experimentally for a piezoelectric beam energy harvester: Simple Resistive Load, Inductive Load, standard AC-DC, and Inductive AC-DC circuits. An Inductive Load circuit is built by adding an inductor to a Simple Resistive Load circuit, while an Inductive AC-DC circuit is built by adding an inductor to a standard AC-DC circuit. Experimental results indicate that the Inductive Load and the Inductive AC-DC circuits avail the Simple Resistive Load and standard AC-DC circuits respectively. The inductive AC-DC circuit shows a 6.7% increase in the output power compared to the standard AC-DC circuit.

Investigating Piezoelectric Energy Harvesting Circuits for Piezoelectric Flags

Abstract: This paper provides a comparison between two different energy harvesting circuits for a piezoelectric flag subjected to uniform flow. Between two circuits tested, one is Simple Resistive Load, and the other one is the standard AC-DC circuit. To experimentally investigate these circuits, the piezoelectric flag output voltage has been studied under various wind speeds in a wind tunnel. The simple resistive load circuit provides an alternating voltage, and not a DC voltage. The standard AC-DC circuit is used to convert the AC voltage into a DC voltage; however, the power dropped as a result of the voltage drop across the forward-biased diodes.Copyright © 2015 by ASME

Experimental Investigation for Enhancing the Output Power of a Piezoelectric Energy Harvester

Abstract: This paper investigates an experimental approach for enhancing the output power of a piezoelectric energy harvester. The proposed method adopts inductance to reduce the effect of the piezoelectric harvester’s impedance, and boost the output power. Four electrical circuits for a piezoelectric beam harvester are investigated experimentally; Simple Resistive Load (SRL), Inductive Load (IL), Standard AC-DC, and Inductive AC-DC circuits. The results show that the adaptation of inductor in the IL and Inductive AC-DC improves the output power compared to the SRL and Standard AC-DC respectively. The Inductive AC-DC circuit is shown to increase the output power by 6.7% in comparison to the existing standard AC-DC circuits.Copyright © 2017 by ASME

Coupled flexural-torsional forced vibration analysis of a piezoelectrically-actuated double-cantilever structure

Abstract: In this paper, the forced coupled flexural-torsional vibration of a piezoelectrically-actuated double-cantilever structure is investigated. The double-cantilever structure is composed of two uniform and identical Euler-Bernoulli cantilever beams connected by a rigid tip connection at their free ends. There is also a piezoelectric layer on the top surface of each cantilever beam. The characteristic equation for the coupled flexural-torsional vibrations of the structure is derived and solved to determine the natural frequencies. The time response to the forced vibrations of the structure is studied using the Galerkin approximation method. The effects of dimensional parameters, including the length of the cantilever beams and the length of the tip connection, and the piezoelectric input voltage on the coupled flexural-torsional natural frequencies and amplitude of the vibrations of the structure are investigated analytically and experimentally. The results show that the coupled flexural-torsional fundamental frequency of the piezoelectrically-actuated double-cantilever structure decreases as either the length of the cantilever beams or the tip connection is increased. Moreover, the amplitude of the coupled flexural-torsional vibrations of the structure is proportional to the piezoelectric input voltage, however, the slope of the curves depends on dimensional parameters. For a given voltage, the effect of either of the aforementioned dimensional parameter on the amplitude of vibrations depends on the other dimensional parameter such that there is a turning point in all the curves, whose location depends on the configuration of the structure.

Portable Wind Energy Harvesters for Low-Power Applications: A Survey.

Abstract: Energy harvesting has become an increasingly important topic thanks to the advantages in renewability and environmental friendliness. In this paper, a comprehensive study on contemporary portable wind energy harvesters has been conducted. The electrical power generation methods of portable wind energy harvesters are surveyed in three major groups, piezoelectric-, electromagnetic-, and electrostatic-based generators. The paper also takes another view of this area by gauging the required mechanisms for trapping wind flow from ambient environment. In this regard, rotational and aeroelastic mechanisms are analyzed for the portable wind energy harvesting devices. The comparison between both mechanisms shows that the aeroelastic mechanism has promising potential in producing an energy harvester in smaller scale although how to maintain the resonator perpendicular to wind flow for collecting the maximum vibration is still a major challenge to overcome for this mechanism. Furthermore, this paper categorizes the previously published portable wind energy harvesters to macro and micro scales in terms of their physical dimensions. The power management systems are also surveyed to explore the possibility of improving energy conversion efficiency. Finally some insights and research trends are pointed out based on an overall analysis of the previously published works along the historical timeline.

Wave propagation and vibration in intelligent nanoplates: A mechanical modeling approach

Abstract: In this article, wave propagation responses of a double-layer magneto-electro-viscoelastic (DLMEVE) nanoplate as an intelligent material is studied via modified couple stress and nonlocal strain gr...

Circuit Optimization for Enhancing the Output Power of a Piezoelectric Energy Harvester

Abstract: In this paper, a new method is proposed for improving a piezoelectric energy harvester’s output power. A piezoelectric vibration energy harvester has an inherent internal capacitance. The new approach adopts inductance to reduce the reactance of the internal capacitance and enhance the output power. To show the practicality of this method, four electrical circuits are investigated numerically and experimentally for a piezoelectric beam energy harvester: Simple Resistive Load, Inductive Load, standard AC-DC, and Inductive AC-DC circuits. An Inductive Load circuit is built by adding an inductor to a Simple Resistive Load circuit, while an Inductive AC-DC circuit is built by adding an inductor to a standard AC-DC circuit. Experimental results indicate that the Inductive Load and the Inductive AC-DC circuits avail the Simple Resistive Load and standard AC-DC circuits respectively. The inductive AC-DC circuit shows a 6.7% increase in the output power compared to the standard AC-DC circuit.

Coupled flexural-torsional forced vibration analysis of a piezoelectrically-actuated double-cantilever structure

Abstract: In this paper, the forced coupled flexural-torsional vibration of a piezoelectrically-actuated double-cantilever structure is investigated. The double-cantilever structure is composed of two uniform and identical Euler-Bernoulli cantilever beams connected by a rigid tip connection at their free ends. There is also a piezoelectric layer on the top surface of each cantilever beam. The characteristic equation for the coupled flexural-torsional vibrations of the structure is derived and solved to determine the natural frequencies. The time response to the forced vibrations of the structure is studied using the Galerkin approximation method. The effects of dimensional parameters, including the length of the cantilever beams and the length of the tip connection, and the piezoelectric input voltage on the coupled flexural-torsional natural frequencies and amplitude of the vibrations of the structure are investigated analytically and experimentally. The results show that the coupled flexural-torsional fundamental frequency of the piezoelectrically-actuated double-cantilever structure decreases as either the length of the cantilever beams or the tip connection is increased. Moreover, the amplitude of the coupled flexural-torsional vibrations of the structure is proportional to the piezoelectric input voltage, however, the slope of the curves depends on dimensional parameters. For a given voltage, the effect of either of the aforementioned dimensional parameter on the amplitude of vibrations depends on the other dimensional parameter such that there is a turning point in all the curves, whose location depends on the configuration of the structure.