Study Of Piezoelectric Energy Harvester Research Articles

System-level finite element analysis of piezoelectric energy harvesters with rectified interface circuits and experimental validation

The finite element method (FEM) has been widely used for numerical studies of piezoelectric energy harvesting (PEH) systems, through commercial finite element (FE) packages or specially developed FE formulations. As a convenient computational tool, FEM can deal with systems of high complexity and has evolved into a multiphasic solution to coupled problems in engineering. However, most of FE packages and formulations are limited to coupled-field simulations of PEH systems connected with a linear circuit. On the other hand, rectified circuits are a critical component in practical applications because electronic devices such as wireless sensor nodes and wearable electronics require a DC power supply. Based on the equivalent impedance analysis, this paper proposes a method to enable a coupled-field study of piezoelectric energy harvesters with the standard AC-DC interface circuit through an equivalent linear circuit. The proposed method enables FE packages and formulations to analyze, design, and optimize PEH harvesters at the system level, by either adding the capability of simulating rectified circuits, or reducing a nonlinear circuit interface simulation into a faster and more stable linear simulation that can be solved more conveniently. This equivalent linear circuit method was applied to a rectangular shaped bimorph beam harvester in ANSYS and validated experimentally. The results also match well with those obtained from a system-level analytical approach. As an application example, a comparison study was performed between the rectangular and triangular energy harvesters using FE packages and the proposed equivalent circuit, given the same natural frequency and material volume. In addition, the implementation of this method with FE formulations is briefly outlined and discussed.

Assessment of PZT (Soft/Hard) Composites for Energy Harvesting

This research is focused on piezoelectric energy harvesting at high pressure fields and low frequency applications. Lead Zirconate Titanate (PZT) is the primary piezoelectric evaluated with a focus on different PZT types (soft and hard). Study of piezoelectric energy harvesting has been done earlier in cantilever designs however this study concentrates on the d33 mode. Several PZT samples and geometries have been tested as well as composite structures with different PZT types. The utilization of electrodynamic test systems and simulation tools used for the evaluation of designed structure property relations. Converted power is compared among various samples and 2:2 composite structure design was found to outperform other configurations in term of electromechanical power conversion. Experimental tests produce an output power as high as 31mW at a force of 2.5kN and frequency of 10Hz. Further investigation into 2:2 composites was conducted to optimize electromechanical output power.

Modeling of nonlinear dynamic characteristics and experimental study of piezoelectric energy harvesters with a panel type structure

Panel flutter vibration is a typical aeroelastic phenomenon taking place in flying aircrafts as they move at high speed. The vibration has been a hot academic research aspect. The present paper focuses on converting this aerodynamic mechanical vibration into useful electricity by using piezoelectric patches. A mathematical Euler-Bernoulli distributed model of the piezoelectric energy harvesting system is established to investigate nonlinear dynamical behaviour of a piezoelectric cantilever plate. The dynamical responding ability of energy harvesting is numerically calculated. Influences of the length and the thickness of piezoelectric layer, the external resistance and wind velocity on the output performance are emphatically explored. A series of prototypes of piezoelectric energy harvesters with different physical dimensions were designed and manufactured. Wind tunnel experiments were setup and carried out at different wind velocities. The experimental results show that the harvesting power gets enhanced as increasing the wind velocity. The maximum power could be obtained at condition of a reasonable piezoelectric length and width. Maximum power is 2.0 mW at wind speed of 11.0 m/s. This work provides a strong theoretical and experimental basis for the study of aerodynamic energy harvesting from panel aircrafts.

Energy harvesting from quasi-static deformations via bilaterally constrained strips

Piezoelectric energy harvesting from ambient vibrations is well studied, but harvesting from quasi-static responses is not yet fully explored. The lack of attention is because quasi-static actions are much slower than the resonance frequency of piezoelectric oscillators to achieve optimal outputs; however, they can be a common mechanical energy resource: from large civil structure deformations to biomechanical motions. The recent advances in bio-micro-electro-mechanical systems and wireless sensor technologies are motivating the study of piezoelectric energy harvesting from quasi-static conditions for low-power budget devices. This article presents a new approach of using quasi-static deformations to generate electrical power through an axially compressed bilaterally constrained strip with an attached piezoelectric layer. A theoretical model was developed to predict the strain distribution of the strip’s buckled configuration for calculating the electrical energy generation. Results from an experimental investigation and finite element simulations are in good agreement with the theoretical study. Test results from a prototyped device showed that a peak output power of 1.33 μW/cm2 was generated, which can adequately provide power supply for low-power budget devices. And a parametric study was also conducted to provide design guidance on selecting the dimensions of a device based on the external embedding structure.

Study of piezoelectric energy harvesters connected by spring

Study of piezoelectric energy harvesters connected by spring

Piezoelectric Energy Harvesting with a Clamped Circular Plate: Analysis

Energy harvesting using piezoelectric materials is not a new concept, but its small generation capability has not been attractive for mass energy generation. For this reason, little research has been done on the topic. Recently, increased interest in wearable computer concepts and remote electrical devices has provided motivation for more extensive study of piezoelectric energy harvesting. The theory behind cantilever-type piezoelectric elements is well known, but the transverse moving plate elements, which can be used in energy generation from pressure sources is not yet fully developed. The power generation in a pressure-loaded plate depends on several factors. Among them, the thickness of each layer is important, as is the electrode pattern used. In this article, two clamped circular plate structures, a fully electroded unimorph, and a so-called regrouped electrode unimorph, are modeled. These models are then used to calculate energy generation with varying thickness ratios. The results of this analysis are presented with an eye toward guidelines for design of useful energy harvesting structures.