Mounir Meddad

Mechanical characterization of an electrostrictive polymer for actuation and energy harvesting

Electroactive polymers have been widely used as smart material for actuators in recent years. Electromechanical applications are currently focused on energy harvesting and actuation, including the development of wireless portable electronic equipment autonomous and specific actuators such as artificial muscles. The problem to be solved is to make its devices the most efficient, as possible in terms of harvested energy and action. These two criteria are controlled by the permittivity of the electrostrictive polymer used, the Young’s modulus, and their dependence on frequency and level of stress. In the present paper, we presented a model describing the mechanical behaviour of electrostrictive polymers with taking into account the mechanical losses. Young’s modulus follows a linear function of strain and stress. However, when the elongation becomes higher, the data obtained from this strain linear trend and significant hysteresis loops appear the reflections on the existence of mechanical losses. In this wo...

An adaptive prototype design to maximize power harvesting using electrostrictive polymers

The harvesting energy with electrostrictive polymers has great potential for remote applications such as invivo sensors, embedded micro-electro-mechanical systems devices, and distributed network instruments. A majority of current research activities in this field refers to classical piezoelectric ceramics, but electrostrictive polymers offer promise of energy harvesting with few moving parts; power can be produced by simply stretching and contracting a relatively low-cost rubbery material. The use of such polymers for energy harvesting is a growing field, which has great potential from an energy density viewpoint. The output power is inversely proportional to the harvesters frequency bandwidth. Consequently, it is much harder to efficiently harvest power from low-frequency sources with a large frequency band response and with a very small system size than from a stabilized high-frequency vibration source. This paper presents a new structure that is able to predict mechanical frequency excitation in orde...

Evaluation by fast Fourier transforms analysis of energy harvesting in electrostrictive polymers driven by an electric field and a mechanical excitation

Electrostrictive polymers offer the promise of energy harvesting with few moving parts where power can be produced simply by stretching and contracting a relatively low-cost rubbery material. The use of such polymers for energy harvesting is a growing field, which has great potential from an energy density viewpoint. Basically, the relative energy gain depends on the current induced by the mechanical strain and frequency. A previous study in the Laboratoire de Génie Electrique et Ferroélectricité laboratory has indicated that one can measure the dielectric constant, the Young’s modulus, and the electrostrictive coefficient of a polymer film by determining the current flowing through the sample when the polymer film was simultaneously driven by an electrical field and mechanical excitation. The goal of this study has thus been to develop a solution for artificially increasing the coupling factor of electrostrictive materials, based on the optimization of the frequency of the electric field and the amplitude strain of the mechanical excitation leading to an increase in the generated current. When relating this parameter with a transverse strain of 5% and a bias field of 10 V/µm, it was found that such a process rendered it able to increase the converted power to 14 µW at a mechanical frequency of 6 Hz. The converted power was much higher than for the frequency of 3 Hz for which a low power was consumed by the polarization of the polymer. The theoretical analysis was supported by the experimental investigations. The contribution of this study provides a framework for developing energy harvesting techniques that should improve the overall performance of the system.

Mechanical effect on the performance of electrostrictive polymers for energy harvesting

Recent trends in energy conversion mechanisms have demonstrated the abilities of electrostrictive polymers for converting mechanical vibrations into electricity. In particular, such materials present advantageous features such as a high productivity, high flexibility, and ease of processing; hence, the application of these materials for energy harvesting purposes has been of significant interest over the last few years. The purpose of this paper is to propose the mechanical effect on the performance of electrostrictive polymers for energy harvesting. when the sample simultaneously driven by an electrical field and a mechanical excitation. Experimental measurements of the harvested power has been compared with the theoretical behavior predicted by the proposed model. A good agreement was observed between the experimental and the theoretical results. Finally, the results indicated that the strain was the crucial parameter for a good efficiency of the electromechanical conversion with electrostrictive polymers.

Effect of temperature on the PV cells and improving their performance by the use of thermo generators

ABSTRACT In this work we propose a new approach to recovering thermoelectricity to improving the efficiency of a photovoltaic (PV) generator under the high temperature as the desert weather. The proposed system composed on two parts, the first is the thermo generator, when is used for a thermo energy harvesting from the PV temperature, the second is to use the energy recovered by the thermo generator to power a fan to cool a photovoltaic panel PV cells. Tests based on such low power fan cooling system show a 3% increase on the voltage generated by a PV panel.

Design and construction of a multifunction piezoelectric transformer

In recent years, piezoelectric materials have particularly found advantageous field of application in electrical energy’s conversion. Especially, the piezoelectric transformers are becoming more and more usable in electrical devices owing to several advantages such as small size, high efficiency, no electromagnetic noise, and non-flammability. The purpose of this study was to investigate a transformer design that allows having multi-functionality with different efficiency and wider range of voltage gain at resonance frequency. The piezoelectric transformer construction utilizes radial mode both at the input and output port and has the unidirectional polarization in the ceramics. An electromechanical equivalent circuit model based on Mason’s equivalent circuit was developed so as to describe the characteristics of the piezoelectric transformer. Excellent matching was found between the simulation data and experimental results. Finally, the results of this study will allow to deterministically designing multifunction piezoelectric transformers with specified performance.

New material connected with Matlab for physicals characteristics tracer of a thermogenerator

Abstract This paper presents new hardware equipments low-cost and the software for researcher to monitoring and diagnosis of thermo-electric generator modules (TEG). The system designed to allow the physical characteristics tracer and reveals the internal resistance of thermogenerator modules where tested under different values of temperature, and provides also the information of maximum power point. This tracer developed based on a microcontroller board family called ChipKIT Max32 which is connected to Matlab\ Simulink. The load of this tracer based on a capacitor varying. The output results data acquisition of TEG can be traced on an oscilloscope or using Matlab environment. These results showed the effectiveness of the present prototype.

Improved modal observer for modal SSDI-Max

Abstract The objective of this paper is to improve a semi-active control of structural vibrations, which is Synchronised Switch Damping on Inductor Maximum. The improvement is attained by adding a system to estimate the structure modal displacement. A model of smart structure shunted to resonant circuit is used and tested with MatlabTM environment and the performance of the new strategy based on Lenear Quadratic Guaussian and Neuro-Fuzzy observer are presented and compared with that one based on Proportional Integral Derivative observer. Results shows the new technique effectiveness when conventional one reaches its limits in the wide bande frequency case.

Modelling and diagnostic of an ultrasonic piezoelectric actuator

ABSTRACT Modeling of piezoelectric motors is a difficult task because their characteristics are affected by various factors such as materials properties, electrical and mechanical boundary conditions. This work presents the modeling of piezoelectric motor via bond graph method and used for the diagnostic. This method is an innovative way to analyse the effects of different design variables on the objective function but can be also considered as an optimization stage of the study. The validation and the development of bond graph models are based on physical insight to aid in structural damage detection and use the technique of optimal sensors placement.