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Finite Element Analysis of Vehicle Load Effect on Harvesting Energy Properties of a Piezoelectric Unit  [PDF]
Chunhua Sun, Hongbing Wang, Jie Liu, Guangqing Shang
Energy and Power Engineering (EPE) , 2015, DOI: 10.4236/epe.2015.710047
Abstract: To realize the goal of harvesting energy from pavement vibration on a large scale, a new type of piezoelectric harvesting units as the energy transducer has been proposed. The piezoelectric harvesting units are paved 40 mm below the asphalt, which is the same as thickness of the top layer of typical asphalt pavement in China. The spacing distance is 2200 mm, which is the same as the one between two tires of a normal vehicle. A mathematical model of the unit is deduced on Meda empirical formula and Hamilton principle and piezoelectric equations. Effects of the external vehicle load on its harvesting energy properties and pavement deformation and stress are analyzed with the finite element method. The results show that the excited voltage is linearly variation with contact pressure while the harvested electrical energy exponential varies with contact pressure. The more the contact pressure is, the larger the harvested electrical energy and the deformation and stress are. The harvested electrical energy also increases with the load frequency. At least 100 mJ of electrical energy can be collected with the proposed piezoelectric harvesting unit. It shows that the technology application of the piezoelectric harvesting energy from pavement is promising.
Energy Harvesting Using an Analog Circuit under Multimodal Vibration  [PDF]
Shigeru Shimose,Kanjuro Makihara,Junjiro Onoda
Smart Materials Research , 2013, DOI: 10.1155/2013/736487
Abstract: The efficiency of harvesting energy from a vibrating structure using a piezoelectric transducer and a simple analog circuit is investigated experimentally. This analog circuit was originally invented for a synchronized switch damping on inductor (SSDI) technique, which enhances the damping of mechanical vibration. In this study, the circuit is used to implement a synchronized switch harvesting on inductor (SSHI) technique. A multiple degree of freedom (MDOF) structure is excited by single sinusoidal forces at its resonant frequencies and by random forces. The piezoelectric transducer converts this mechanical energy into electrical energy which is harvested using a standard rectifier bridge circuit with and without our analog circuit. Experimental results show that our analog circuit makes it possible to harvest twice as much energy under both single sinusoidal and random vibration excitations. 1. Introduction Energy harvesting techniques have been studied extensively in recent years. Energy harvesting is a process by which energy is captured and stored. Energy can be harvested from various power sources, including wind power, solar power, ocean tides, heart, magnetic fields, and structural vibrations. We focused on the vibration energy of a structure, using the piezoelectric effect to convert structural vibration energy into electrical energy. There is substantial research on this technique, as reviewed by Sodano et al. [1]. Lesieutre et al. [2] addressed the damping associated with energy harvesting from structural vibrations. Badel et al. [3–5] proposed a synchronized switch harvesting on inductor (SSHI) technique to improve energy harvesting. SSHI is based on vibration suppression technique named synchronized switch damping on inductor (SSDI). Both SSHI and SSDI use a piezoelectric transducer attached to the structure and connected to an inductive circuit having an on-off switch [6–10]. The switch in the circuit is flipped at each extremum of displacement of the structure. A displacement sensor and a controller are needed to synchronize the switching commands with the mechanical vibration. In a self-powered system, these sensors and controllers need to be driven using a fraction of the harvested energy. We previously invented an analog circuit that automatically performs switching without an external energy source [11]. We describe in this paper how this analog circuit enhances the energy harvesting performance when used with SSHI. Although many studies [12–14] have been conducted on SSHI, most of them are limited to the sinusoidal vibration of a
Multi-Direction Piezoelectric Energy Harvesting Techniques  [PDF]
Chunhua Sun, Guangqing Shang
Journal of Power and Energy Engineering (JPEE) , 2019, DOI: 10.4236/jpee.2019.79003
Abstract: With the development of portable and self-powering electronic devices, micro-electromechanical system (MEMS) and wireless sensor networks, research on piezoelectric energy harvesting techniques has been paid more and more attention. To enhance the ambient adaptability and improve the generating efficiency, the multi-directional piezoelectric energy harvesting techniques turns to be a research hotspot. The current status of the multi-directional piezoelectric energy harvesting techniques was firstly reviewed. The characteristics of existed multi-directional piezoelectric harvester were then analyzed. An improved structure of multi-directional piezoelectric harvester was finally proposed. The multi-directional piezoelectric energy harvester has a good prospect in miniaturization, more sensitive to vibration directions and better energy efficiency.
Energy Harvesting Strategy Using Piezoelectric Element Driven by Vibration Method  [PDF]
Dong-Gun Kim, So-Nam Yun, Young-Bog Ham, Jung-Ho Park
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.22014
Abstract: This study demonstrates a method for harvesting the electrical power by the piezoelectric actuator from vibration energy. This paper presents the energy harvesting technique using the piezoelectric element of a bimorph type driven by a geared motor and a vibrator. The geared motor is a type of PWM controlled device that is a combination of an oval shape cam with five gears and a speed controller. When using the geared motor, the piezoelectric element is size of 36L×13W×0.6H. The output voltage characteristics of the piezoelectric element were investigated in terms of the displacement and vibration. When using the vibrator, the electric power harvesting is based on piezoelectric effect and piezoelectric vibrator consists of a magnetic type oscillator, a cantilever, a bimorph actuator and controllers. Low frequency operating technique using piezoelectric vibrator is very important because normal vibration sources in the environment such as building, human body, windmill and ship have low frequency characteristics. We can know from this study results that there are many energy sources such as vibration, wind power and wave power. Also, these can be used to the energy harvesting system using smart device like piezoelectric element.
Energy Harvesting Process Modelling of an Aeronautical Structural Health Monitoring System Using a Bond-Graph Approach
International Journal of Aerospace Sciences , 2012, DOI: 10.5923/j.aerospace.20120105.03
Abstract: Energy Harvesting is a promising solution for powering Structural Health Monitoring (SHM) systems since various mechanical energy sources are generated by aircraft. Today, the main technique to harvest energy consists of using a specific conversion device to provide power to the SHM system. In this paper however, a novel technique to obtain a self-powered SHM system for aeronautical structures is proposed. This SHM system aims to have a double functionality: it will carry out classical SHM tasks using piezoelectric transducers bonded onto the aircraft structure and will also be fully autonomous since the same transducers will convert the mechanical vibrations of the structure into electrical power. Using a bonded piezoelectric transducer to harvest energy will also bring wideband frequency energy harvesting capability. This autonomous system using a unique transducer being particularly innovative, the objective of this paper is to provide a complete Bond Graph model of the energy harvesting process in order to allow the optimisation of its performances. This approach is well-suited to monitor the power and energy transfer carried out during the process since it takes into account the interaction between multiphysics systems, here the electrical and mechanical domains in terms of power and energy variables. Consequently, each part of the energy harvesting, i.e. the mechanical vibration of the host structure, the vibration within the SHM energy harvester volume, the piezoelectric electromechanical conversion and the terminal electric load have been modelled analytically using this Bond Graph approach. Then, each submodel has been verified with a baseline Finite Element model. Good agreements have been found and it has been possible to carry out an estimation of the power harvested by the SHM energy harvester for a given mechanical excitation using this innovative complete analytical Bond Graph model.
A thermal insulation method for a piezoelectric transducer
Song Wu,Hong Chen,JiaHua Gu,HongRu Yu
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0366-y
Abstract: This study deals with the sources of signal distortion of a piezoelectric transducer heated by measured gas flow. These signal distortions originate from both unloading of preload on a piezocrystal because of expansion of a diaphragm in the test apparatus and the pyroelectric effect of a heated piezoelectric crystal. A plastic film on the diaphragm of the transducer can effectively insulate the diaphragm and the piezocrystal within transducer from heating by gas flow, eliminating the sources of distortion. A method for evaluating the thickness of the film is proposed.
Voltage Generated Characteristics of Piezoelectric Ceramics Cymbal Transducer  [PDF]
Long Wu, Ming-Cheng Chure, King-Kung Wu, Chia-Cheng Tung
Journal of Materials Science and Chemical Engineering (MSCE) , 2014, DOI: 10.4236/msce.2014.210005
Abstract:

In this study the relation between the generated open circuit output voltages of the piezoelectric ceramics Cymbal transducers with applied impact mechanical energy is studied. The output voltages of piezoelectric ceramics Cymbal transducers are increased with the increasing of the applied mechanical energy. Under the same impact mechanical energy, the generated open circuit output voltages of the piezoelectric ceramics Cymbal transducer is much higher than that of uncapped piezoelectric ceramics disk alone. The generated open circuit output voltages of the piezoelectric ceramics Cymbal transducer depend on the geometry parameters and the metal thickness of end-cap. The generated open circuit voltage of piezoelectric ceramics Cymbal transducer with thick metal thickness is small than that with thin metal thickness.

Highly efficient integrated rectifier and voltage boosting circuits for energy harvesting applications  [PDF]
D. Maurath,C. Peters,T. Hehn,M. Ortmanns
Advances in Radio Science : Kleinheubacher Berichte , 2008,
Abstract: This paper presents novel circuit concepts for integrated rectifiers and voltage converting interfaces for energy harvesting micro-generators. In the context of energy harvesting, usually only small voltages are supplied by vibration-driven generators. Therefore, rectification with minimum voltage losses and low reverse currents is an important issue. This is realized by novel integrated rectifiers which were fabricated and are presented in this article. Additionally, there is a crucial need for dynamic load adaptation as well as voltage up-conversion. A circuit concept is presented, which is able to obtain both requirements. This generator interface adapts its input impedance for an optimal energy transfer efficiency. Furthermore, this generator interface provides implicit voltage up-conversion, whereas the generator output energy is stored on a buffer, which is connected to the output of the voltage converting interface. As simulations express, this fully integrated converter is able to boost ac-voltages greater than |0.35 V| to an output dc-voltage of 2.0 V–2.5 V. Thereby, high harvesting efficiencies above 80% are possible within the entire operational range.
A rotary piezoelectric actuator using longitudinal and bending hybrid transducer
Yingxiang Liu,Xiaohui Yang,Weishan Chen,Junkao Liu
AIP Advances , 2012, DOI: 10.1063/1.4766676
Abstract: A rotary piezoelectric actuator using bolt-clamped type transducer with double driving feet is proposed in this study. The first-order longitudinal and fourth-order bending vibration modes are superimposed in the actuator to produce elliptical movements on the driving tips. Longitudinal PZT and bending PZT are clamped between the exponential shape horns and the flange by bolts. The vibration shape changes of the actuator are presented to give a clear explanation of its working principle. Several structural parameters of the exponential shape horn are selected and adjusted to accomplish the tuning process of the longitudinal and bending resonance frequencies. The input impedance and vibration characteristics are calculated by using FEM method; the gained results verify the feasibility of the proposed actuator. After the fabrication of a prototype, its vibration characteristics are measured by using a scanning laser Doppler vibrometer; the tested results are in good agreement with the FEM calculated results. The mechanical output performance experiments state that the prototype achieves a maximum speed of 129 r/min and a maximum torque of 1.5 Nm.
Improved Performance of the Piezoelectric Monomorph with Perpendicular Electrode Connections for Sensing and Energy Harvesting  [PDF]
Ming Ma,Zhenrong Li,Xiaoyong Wei,Zhuo Xu,Xi Yao
Smart Materials Research , 2013, DOI: 10.1155/2013/957460
Abstract: Piezoelectric monomorph, which has only one element, is a potential structure for piezoelectric applications in some extreme conditions. But as the restriction of the strain neutral layer, the traditional parallel electrode connection is not effective for sensing and energy harvesting. In this paper, perpendicular electrode connections were designed to utilize the nonuniform shear piezoelectric effect in the cross section of the monomorph, which made the monomorph avoid the restriction of the strain neutral layer. The PZT5 ceramic monomorph was preliminarily studied in this experiment. By comparing seven forms of perpendicular electrode connections with the traditional parallel electrode connection, the whole superposed perpendicular electrode connection is considered as the optimal output way for the monomorph. It can produce 13?V peak-to-peak (pk-pk) voltage in open circuit and 14.56?μW maximum power with the matching resistance, which are much more than the parallel electrode connection 0.78?V and 0.14?μW. 1. Introduction Piezoelectric cantilever is widely used in the piezoelectric device for sensing and energy harvesting [1–6]. At room temperature and ambient pressure, unimorph and bimorph, which utilize the lateral extensional piezoelectric effect, are considered as a promising solution for sensing and energy harvesting [7, 8]. But when both of the above composite structures are used under the relative tough environment, such as high temperature and high pressure or low temperature and low pressure, the stability and performance of the device will be lower as the thermal-oxidative degradation and the low temperature brittleness of the bonding materials between different components. Even in the normal situation, the internal stresses and the permanent strain in the bonding layer will lead to the rapid deterioration of the device after long time using [9]. As for the simplest transducer that has only one piezoelectric component, the piezoelectric monomorph avoids the bonding issues and is considered as the only solution in the extreme conditions. But the existence of the strain neutral layer, which is in the middle of the thickness of the piezoelectric element, neutralizes the positive and negative induced charges [10]. As a result, with the traditional parallel electrode connection, the monomorph is not effective in the piezoelectric applications. In order to improve the performance of the monomorph, many studies have been focused on the nonuniform polarization inside the piezoelectric materials. Based on the nonuniform distribution of the electric
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