Single Piezoelectric Cantilever Research Articles

Interplay between internal resonance and nonlinear magnetic interaction for multi-directional energy harvesting

To investigate the coupling effects between the internal resonance and nonlinear magnetic interaction for multi-directional energy harvesting, this study proposed a single piezoelectric cantilever–nonlinear magnetic pendulum structure. The proposed structure was mainly composed of a piezoelectric cantilever beam, a magnetic pendulum fixed at the free end of the beam, and a base permanent magnet below the pendulum. Internal resonance was induced by the nonlinear coupling between the pendulum motion in the two-dimensional space and the beam bending vibration at resonance. The magnetic interactions between the magnetic pendulum and the base magnet introduced nonlinearity. The proposed structure was theoretically modeled and experimentally realized to demonstrate its energy harvesting capabilities. Owing to the positive coupling effects between the internal resonance and nonlinearity in the proposed structure under the properly chosen parameters, the experimental results showed that the internal resonance bandwidth of the proposed structure for the x-direction energy harvesting was three times wider than that of the traditional piezoelectric cantilever-pendulum system. Meanwhile, the proposed structure also achieved an additional internal resonant frequency range (3.4 Hz–4.3 Hz) for improving the z-direction energy harvesting performance. The experimental maximum power output of the proposed structure achieved 0.64 mW at 7.5 Hz in the investigated frequency domain.

A new concept of frequency-excitation-up conversion to improve the yield of linear piezoelectric generators

A new and novel frequency-excitation up-conversion (FEUC) mechanism achieved by converting low-frequency excitation into friction-induced vibration (FIV) is proposed to improve the output power of linear piezoelectric energy harvesters at ultra-low ambient frequencies. For comparison, a conventional resonant energy harvester and an impact-driven energy harvester are created, the output power is measured at the resonant frequency under a 0.5 g driving acceleration. Then, a friction system driven by reciprocating sliding and capable of generating FIV is established. The driving reciprocating is equivalent to the low-frequency ambient vibration, and a single piezoelectric cantilever beam is added to the friction system for energy recovery. The results show that, compared with the impact-driven energy harvester, the vibration frequency can be increased hundreds of times, and the excitation level can be improved several orders of magnitude by the friction nonlinearities. The impedance of the energy harvester is reduced significantly due to a sharp increase in the vibration frequency. In addition, the open-circuit voltage amplitude is not substantially lowered due to the significantly increased excitation level, even though the piezoelectric cantilever beam operates in a high-frequency condition and in the absence of resonance. Therefore, the output power is dramatically improved. The effectiveness and superiority of the FEUC strategy proposed in this work has been demonstrated.

Analysis of angular position, dimension and material of a cantilever piezoelectric energy harvester

The performance of an angular vibrating single piezoelectric cantilever beam energy harvester in a flexural mode was analyzed. In this research the approaches of theory, finite element, and experiment have been undertaken to study the effects of angular position, mechanical properties, and dimensions on the output power and resonance frequency of a piezoelectric cantilever beam. The phase shift is an important phenomenon observed in this system because of the angular position of the beam about its longitudinal axis. Frequency shift due to the angular position is usually observed in experiments. However, it has not been studied theoretically until now. The angular position not only affects the resonance frequency but also the amount of output power from the lead zirconate titanate ceramic bonded on it. Furthermore, beam and piezoelectric dimensions have a major effect on power output and resonance frequency. Another aspect considered in this research is the effect of materials on power and frequency which have been studied for aluminum, copper, and steel.

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.

Enhanced piezoelectric energy harvester performance using magnetic force and thermal energy

ABSTRACTOne possible approach of improving the performance of energy harvesters is to use energy harvester with an external magnetic force to create a nonlinear coupling system. In this work, we report experimental results of a single piezoelectric cantilever beam (PCB) with tip mass or conventional piezoelectric energy harvester (CPEH), and the effect of applying an external magnetic force. The output voltage and power at optimal resistance was 7.62 V and 0.62 mW, respectively, at the resonance frequency of approximately 11 Hz of a CPEH. Also, the output voltage and average power at optimal resistance was 8.56 V and 0.44 mW, respectively, at resonance frequency of 7 Hz of a PCB with fixed opposing magnet. Furthermore, the output voltage and average power at optimal resistance was 13.31 V and 1.77 mW, respectively, at resonance frequency of 11 Hz of a PCB with opposing magnet attached at a second cantilever. In addition, comparison between the experimental results of all different configurations showed a reasonable enhancement of performance of energy harvester when an external magnetic force added over the main PCB. Finally, the performance of a multisource energy harvester with magnetic, thermal and mechanical sources is also presented in this study. In this case, it is demonstrated that increase in output voltage with temperature gradient under effect of magnetic force; the results of 2nd and 3rd model showed 44% and 99% enhancement of its original output voltage value at 1.2 °C and 2.7 °C temperature difference, respectively.

Cantilever Beam Based Piezoelectric Energy Harvester

Abstract With the application of wireless sensor networks become widespread, supply energy for these wireless sensors proves to be a significant issue. Moreover, for the ambient vibration lies everywhere, the vibration can supply energy for the wireless sensor via energy harvester. The piezoelectric energy harvester becomes the research focus for the simple structure and higher energy conversion efficiency. Due to the transcendental equation in distributed parameter model, the numerical method is become powerful complement for theoretical and experimental method. This paper uses ANSYS to analyze the single piezoelectric cantilever in static analysis, model analysis, harmonic response analysis and mechanical-electrical coupling analysis. It analyzes the natural frequency and voltage effect from four aspects which are length to thickness ratio, length to width ratio, the substrate thickness to piezoelectric thickness ratio and seismic mass. Test and measurement for piezoelectric energy harvester is conduct on the testing platform. Macro cantilever beam piezoelectric energy harvester are tested and measured

Structure Design and Simulation Analysis of Multiple Micro Piezoelectric Cantilevers

In order to effectively capture the environment vibration energy, convert it into electricity and supply energy for the microelectronics devices, multiple micro piezoelectric cantilevers are designed. It is composed of more than one piezoelectric cantilever array, which broaden the resonant frequency band of the piezoelectric vibrator, and it can produce resonance or similar to the resonance in a frequency range. Compared to a single piezoelectric cantilever, multiple piezoelectric cantilevers can effectively broaden the resonant frequency and improve the piezoelectric power generation capacity. The simulation results show that the finite element method can provide important theoretical guidance for the structural design of multiple micro piezoelectric cantilevers.

도로용 압전발전발판 설계 및 발전특성 평가

Piezoelectric energy harvester (PEH) as a box type was fabricated in order to harvest mechanical energy imparted to roadways from passing vehicles and convert it into electricity. The PEH was composed of 72 piezoelectric cantilevers with 9 springs with elasticity stick to a bottom of the PEH. For the single piezoelectric cantilever, when a single push with approximately 5 mm displacement was incident to it, power of 0.355 mW was produced at . It is found that the power from the single piezoelectric cantilever increases when spring constant is high. We investigated power of PEH when the moving vehicle passes in it. Power was increased with increasing vehicle speed. When vehicle speed is 30 km/h, power is 20.6 mW.

Vibrated Model and Experiments of Multiple Piezoelectric Cantilevers in Energy Harvesting

A single piezoelectric cantilever is sensitive to the vibration frequency for scavenging ambient energy. The efficiency of the piezoelectric cantilever is very low when the resonance frequency does not match the environmental vibration frequency. In order to increase the frequency band of the piezoelectric cantilever, multiple piezoelectric cantilevers (MPECS) are designed. A vibration model is presented to determine the resonance frequency of MPECS. It can be found that the results obtained from the theoretical model are basically in agreement with the experimental results. Comparing with a piezoelectric cantilever, the MPECS can effectively increase the band of resonance frequency. The generating capacity of MPECS power generation unit is tested. The maximum output power can reach 4.9 mW at a load of 820 ? and a working frequency of 60 Hz. The generated energy can satisfy the demand of low-energy microelectronic products such as network sensors.

A NOVEL MINIATURE OPTICAL SWITCH WITH DOUBLE VERTICAL MICROMIRRORS DRIVEN BY PIEZOELECTRIC CANTILEVER

ABSTRACT This paper presents a novel miniature 2 × 2 optical switch with double vertical micromirrors driven by single piezoelectric cantilever using PZT (Lead Zirconium Titanate) films. Double vertical micromirrors, piezoelectric cantilever and optical fiber V-grooves are integrated on a single silicon chip in compact and low-cost form. The optical switch switches light beams by moving perpendicularly double vertical micromirrors with smooth side surfaces simultaneously which are driven by single piezoelectric cantilever using PZT films. The fabrication process of the optical switch is described. Simulation and analysis have been carried out to evaluate mechanical performance of the optical switch. Due to low insertion loss, small switch size and low power dissipation, this novel optical switch should be promising for optical network applications.

Design, fabrication and RF performances of two different types of piezoelectrically actuated Ohmic MEMS switches

In this paper, we have proposed, fabricated and characterized piezoelectrically actuated RF MEMS (radio-frequency micro-electro-mechanical system) switches. They have been designed to operate at a low operation voltage for advanced mobile/wireless handset applications. The proposed switches are largely composed of piezoelectric cantilever actuators with an Au contact electrode and CPW (coplanar wave) transmission lines suspended over the substrate. Two different types of RF MEMS switches have been suggested to find the better geometry. One has the structure of one single piezoelectric cantilever and a contact electrode attached to its edge with three hinges (type-A), and the other contains four piezoelectric cantilevers that are symmetrically combined through each hinge to support a centered contact electrode (type-B). The two different fabricated (type-A and type-B) RF MEMS switches have insertion losses of −0.22 and −0.23 dB at an operation voltage of 2.5 V and a frequency of 2 GHz, respectively. Although the difference in insertion loss is trivial, there exist different dependences of insertion loss on applied voltage between them. The insertion losses of type-A switches are changed with varying operation voltage because the touching area between the contact electrode and the signal transmission lines is variable. Meanwhile, the type-B switches show nearly constant insertion losses regardless of operation voltage. The type-A and type-B switches have isolation values of −40.8 and −42.5 dB at a frequency of 2 GHz, respectively.

Simple and convenient nonoptical shear force sensor for shear force and near-field optical microscopes

A simple, compact, and inexpensive method for shear force distance regulation is presented. A single piezoelectric cantilever is employed to both dither a fiber probe and to detect the decrease in piezotension-induced voltage as it approaches the sample surface. On resonance, the large piezotension-induced voltage (∼0.2 mV/nm) allows for simple electronics to be used. It is expected to find application both in shear force microscopy and for shear force distance regulation in near-field optical microscopy.