Piezoelectric Energy Harvesting Techniques Research Articles

Piezoelectric energy harvesting systems using mechanical tuning techniques.

In this review, we review the recent research progress and results of piezoelectric energy harvesters applying mechanical tuning techniques in terms of literature background, methods of mechanical tuning, and practical applications. In the past few decades, piezoelectric energy harvesting techniques and mechanical tuning techniques have received increasing attention and made significant progress. Mechanical-tuning techniques are those that allow the resonant vibration energy harvesters the mechanical resonant frequency values to be adjusted to coincide with the excitation frequency. According to the different tuning methods, this review classifies mechanical-tuning techniques based on magnetic action, different piezoelectric materials, axial load, the variable center of gravity, various stresses, and self-tuning and summarizes the corresponding research results, comparing the differences between the same methods. In addition, the current application of the mechanical-tuning techniques is introduced, and the future development of mechanical tuning techniques is analyzed, facilitating the reader to better understand how mechanical-tuning techniques can improve the output performance of energy harvesters.

Energy harvesting pulley

Generating electricity from the available mechanical energy (from a turbine) through an unconventional method involving piezoelectric material can reduce the complications involved in generation & transmission of the energy. Here we have developed an “Energy Harvesting Pulley” which converts the available mechanical energy into electrical energy with the help of piezoelectrics. This pulley is further covered with a layer of abrasive material. With most of the conventional sources of energy running out, the world is slowly moving towards unconventional ones like, solar energy, tidal energy, wind energy etc. Piezoelectric energy harvesting techniques are one such unconventional method of energy generation. The existing AC generators are designed to produce voltages as high as 120 or above & hence need a higher level of insulation. This also makes them overheat. On the other hand, our “Energy Harvesting Pulley” was found to produce AC voltages ranging from 20 V to 60 V by transmitting 1HP power through the pulley. The abrasive layer proved to be a sufficient insulator and it also gives us an additional advantage of reducing slippage. In essence this “Energy Harvesting Pulley” of ours is less costly, easier to insulate, & much safer to handle. Hence it can be used to generate voltages, as low as 20 V and as high as we want them to generate. The voltage generated can be increased even above 120 V by increasing the power transmitted through them.

Piezoelectric Energy Harvesting Solutions: A Review.

The goal of this paper is to review current methods of energy harvesting, while focusing on piezoelectric energy harvesting. The piezoelectric energy harvesting technique is based on the materials’ property of generating an electric field when a mechanical force is applied. This phenomenon is known as the direct piezoelectric effect. Piezoelectric transducers can be of different shapes and materials, making them suitable for a multitude of applications. To optimize the use of piezoelectric devices in applications, a model is needed to observe the behavior in the time and frequency domain. In addition to different aspects of piezoelectric modeling, this paper also presents several circuits used to maximize the energy harvested.

A State-Of-The-Art Review of Car Suspension-Based Piezoelectric Energy Harvesting Systems

One of the most important techniques for energy harvesting is the clean energy collection from the ambient vibration. Piezoelectric energy harvesting systems became a hot topic in the literature and attracted most researchers. The reason behind this attraction is that piezoelectric materials are a simple structure and provide a higher power density among other mechanisms (electromagnetic and electrostatic). The aim of this manuscript is to succinctly review and present the state of the art of different existing vibrational applications utilizing piezoelectric energy harvesting technique. Meanwhile, the main concentration is harvesting energy from a vehicle suspension system. There is a significant amount of dissipated energy from the suspension dampers that is worthy of being harvested. Different mathematical car models with their experimental setup are presented, discussed, and compared. The piezoelectric material can be mounted in different locations such as suspension springs, dampers, and tires. The technique of implementing the harvester and the amount of power harvested from each location are analyzed. The evaluation of the electrical harvesting circuits and different storage devices for the harvested power are also discussed. The paper will also shed light on the variety of potential applications of the harvested energy.

On Broadband Nonlinear Piezoelectric Energy Harvesting Techniques

With the development of portable electronic devices, internet of things, micro-electromechanical system (MEMS) and wireless sensor networks, mirco sources and self-powered devices have been attracted great attention. It is an effective way to supply mirco power or realize the miniaturization of the device via the piezoelectric energy harvesting effect. Therefore, research on piezoelectric energy harvesting techniques has been highly valued. To enhance adaptability and improve harvesting efficiency, the broadband nonlinear piezoelectric energy harvesting technique turns to be a research hotspot. The current status of broadband nonlinear piezoelectric energy harvesting technique with nonlinear stiffness was reviewed according to methods of realizing nonlinearity. The characteristics and existed problems of each kind of nonlinear harvester were then concluded. The nonlinear piezoelectric energy harvester with nonlinear stiffness has a good prospect if its advantages can be given full use.

Multi-Direction Piezoelectric Energy Harvesting Techniques

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.

A preliminary study on the highway piezoelectric power supply system

Pavement piezoelectric energy harvesting technique is to use a Piezoelectric Energy Harvester (PEH) to convert the mechanical energy of vehicles into electrical energy. A lot of research has been done on the technology of piezoelectric energy collection, but it is mainly focused on the theoretical model and the laboratory tests and lacks the on-site performance evaluation. In this paper, a stacked array type PEH is designed with protection package, which can improve the performance and the service life of the PEH. The demonstration project is also carried out to test the field performance. It is found that under the actual vehicle loading, the obtained piezoelectric energy can successfully light LED signs.

Unsymmetrical, interdigital vibration energy harvester: Bandwidth adjustment based on mode separation technique

Vibration-based piezoelectric energy harvesting technique is a promising way for power supply of smart and mobile wireless sensor networks. The novel structures of harvester with low frequency, wide bandwidth and large output power have drawn great attention. In this paper, vibration energy harvester with unsymmetrical, interdigital pick-up structure and voltage synchronous management circuit have been designed, fabricated, and characterized. The working bandwidths of 11.2Hz at simulation and 12.3Hz at experiment have been gained for the designed structure based on mode separation technique in a low vibrational frequency range (below 25Hz) with the acceleration of 1g. Experimental results show that the proposed harvester can generate the output power of about 151.3μW (5.91 times of our previous work), which can maintain the normal work of given electronic devices (containing 18 light emitting diodes) by using a matched voltage synchronous management circuit. These results make it a promising candidate for power supply of low power micro electron devices in some special low frequency vibration environment, such as large engineering, bridge monitoring, wildlife monitoring, etc.

Theoretical modeling and analysis of two-degree-of-freedom piezoelectric energy harvester with stopper

Piezoelectric energy harvesting techniques provide a promising way to transform the vibration energy into electric energy. Since the voltage output peak can drop due to the frequency excitation moving away from the resonance region, the on broadening the bandwidth of operation frequency has drawn great attention. In the paper, a novel two-degree-of-freedom piecewise-linear piezoelectric energy harvester is proposed to achieve wide operation frequency bandwidth by combining the multimodal harvesting technique and nonlinear method. Based on the average method, the analytical solution of the proposed device is achieved. From analytical and experiment results, at an excitation acceleration of 0.3g, as the excitation frequency is up sweeping, the system achieves frequency bandwidth operation of 7.4Hz which is about 5.2 times higher to that of conventional two-degree-of-freedom linear harvester, and the power outputs for the first and second resonances can reach up to 429μW and 411μW, respectively. Due to the close agreement between the calculated values and experiment results, the analytical solution and the theoretical model could be applied to further MEMS fabrication process and optimized design.

Autonomous Wireless Sensors Network Based on Piezoelectric Energy Harvesting

Wireless sensor networks (WSNs) offer an attractive solution to many environmental, security and process monitoring. However, their lifetime remains very limited by battery capacity. Through the use of piezoelectric energy harvesting techniques, ambient vibration can be captured and converted into usable electricity to create selfpowering WSN which is not limited by finite battery energy. This paper investigates analytically and experimentally the performance of a WSN powered by a Piezoelectric Energy Harvesting System (PEHS) and a material block-level modeling considering most key energy consumption of a wireless sensor node in a star topology network is proposed. By using real hardware parameters of existing components, the proposed model is used to evaluate the energetic budget of the node. The sensor node performance is evaluated regarding transmit packet size, duty cycle and the number of nodes that can be deployed. From the spectral properties of the available vibration inside two moving vehicles (automobile and train), the maximal recoverable power for each type of vehicle is estimated. Using a PEHS based on a cantilever beam optimized for low-frequency applications, 6 mW power is recovered in the case of the train while a 12.5 mW power is reached in the case of the automobile. It is observed that the sink may not operate with the recovered energy. However, the sensor node can sense and transmit data with a maximum size of 105.5 kbits when the duty cycle is 4 × 10-15. It is also achieved that the node is most effective when the measured physical phenomena vary slowly, such as the variations in temperature due to thermal inertia. Considering an optimized PEHS based on non-linear processing, it is shown that the sink can operate for 190% improvement of the recovered power.

Low-Grade Waste Vibration Energy Recovery from Hong Kong Franchised Buses

Vibration characterization in moving franchised buses has been performed. Considering the frequency spectrum of vertical acceleration, two distinct vibration peaks at 2.2 and 14 Hz were observed. The root-mean-square acceleration peak values were 5.59×10−6 and 1.95×10−6 g2/Hz, where g is the acceleration due to gravity. Based on the experimental results of vibration frequency characteristics, a conventional piezoelectric cantilever energy harvester with natural frequency tuned at 14 Hz was constructed. This paper presents the application of piezoelectric energy harvester to obtain the low-grade waste vibration energy from Hong Kong franchised buses. Ten different bus routes were selected for the energy harvesting. On average, statistical data showed that for buses traveling from one terminus to another, by using the cantilever piezoelectric energy harvesting technique, the feasible power generated from bus vibration was around 90 μW.

Energetic optimization of a piezo-based touch-operated button for man–machine interfaces

This paper discusses the optimization of a touch-operated button for man–machine interfaces based on piezoelectric energy harvesting techniques. In the mechanical button, a common piezoelectric diaphragm, is assembled to harvest the ambient energy from the source, i.e. the operator’s touch. Under touch force load, the integrated diaphragm will have a bending deformation. Then, its mechanical strain is converted into the required electrical energy by means of the piezoelectric effect presented to the diaphragm. Structural design (i) makes the piezoceramic work under static compressive stress instead of static or dynamic tensile stress, (ii) achieves a satisfactory stress level and (iii) provides the diaphragm and the button with a fatigue lifetime in excess of millions of touch operations. To improve the button’s function, the effect of some key properties consisting of dimension, boundary condition and load condition on electrical behavior of the piezoelectric diaphragm are evaluated by electromechanical coupling analysis in ANSYS. The finite element analysis (FEA) results indicate that the modification of these properties could enhance the diaphragm significantly. Based on the key properties’ different contributions to the improvement of the diaphragm’s electrical energy output, they are incorporated into the piezoelectric diaphragm’s redesign or the structural design of the piezo-based button. The comparison of the original structure and the optimal result shows that electrical energy stored in the diaphragm and the voltage output are increased by 1576% and 120%, respectively, and the volume of the piezoceramic is reduced to 33.6%. These results will be adopted to update the design of the self-powered button, thus enabling a large decrease of energy consumption and lifetime cost of the MMI.

圧電素子によるエネルギ回収を利用したＣＦＲＰはり構造の準能動的制振

The present paper treats a semi-active vibration control based on a synchronized switch damping (SSD) technique. To enhance the performance of semi-active vibration control method, the piezoelectric energy harvesting techniques are adopted instead of constant voltage sources in SSD on voltage sources (SSDV). This harvesting technique exploits the property of piezoelectric vibration to electricity converters, and requires no external voltage source. An experimental verification of the present vibration suppression method named as a synchronized switch damping on piezoelectric energy harvesters (SSDP) for CFRP cantilevered beams is carried out. The experimental results show that the proposed vibration control method is effective for vibration suppression of composite structures as well as SSDV technique. It is also shown that there exist threshold values of generated voltage of the piezoelectric element and excitation frequency of the cantilevered beam in energy harvesting device for achieving stable control effect based on the present method.

Parametric studies on the harvested energy of piezoelectric switching techniques

Piezoelectric energy harvesting techniques have experienced increasing research effortduring the last few years. Possible applications including wireless, fully autonomouselectronic devices, such as sensors, have attracted great interest. The key aspect ofharvesting techniques is the amount of converted and stored energy, because the energysource and the conversion rate is limited. In particular, switching techniques offer manyparameters that can be optimized. It is therefore crucial to examine the influence of theseparameters in a precise manner.This paper addresses an accurate analytical modeling approach, facilitating the calculationof standard-DC and parallel SSHI-DC energy harvesting circuits. In particular the influenceof the frequency ratio between the excitation and the electrical resonance of the switchingLR-branch, and the voltage gaps across the rectifier diodes are studied in detail.Additionally a comparison with the SSDI damping network is performed. Therelationship between energy harvesting and damping is indicated in this paper.