Rotary displacement piezoelectric energy harvester

“This study proposes a novel piezoelectric energy harvester for rotary motion applications. It is based on an annular unimorph plate, mounted on a shaft rotating at a constant angular velocity, under constant amplitude point-wise force. The mathematical model and the analysis was proposed for the inverse problem of a rotating disk under a static stationary force. The disk, however, is assumed to be stationary subjected to a traveling force. The distributed parameter electromechanical equations governing the behavior of the system are provided in closed-form, incorporating both an AC and a simple rectifier circuit. The performance of the energy harvester was compared in both the AC and the rectifier circuits. Multi-modal voltage and vibration frequency responses of the energy harvester have been illustrated and discussed in detail. The performance of the modal coupling terms in both the mechanical and the electrical equations have been investigated. Based on the electromechanical coupling terms, a scheme for prevention of charge cancellation in non-axisymmetric vibration has been proposed. A multiple electrode pattern was used to overcome the charge cancellation. In addition, the prevention of charge cancellation was shown to require a knowledge of the vibratory modes of the system rather than the simple knowledge of the system\u27s dependence on the boundary conditions”--Abstract, page iv

Available Technologies and Commercial Devices to Harvest Energy by Human Trampling in Smart Flooring Systems: a Review

Technological innovation has increased the global demand for electrical power and energy. Accordingly, energy harvesting has become a research area of primary interest for the scientific community and companies because it constitutes a sustainable way to collect energy from various sources. In particular, kinetic energy generated from human walking or vehicle movements on smart energy floors represents a promising research topic. This paper aims to analyze the state-of-art of smart energy harvesting floors to determine the best solution to feed a lighting system and charging columns. In particular, the fundamentals of the main harvesting mechanisms applicable in this field (i.e., piezoelectric, electromagnetic, triboelectric, and relative hybrids) are discussed. Moreover, an overview of scientific works related to energy harvesting floors is presented, focusing on the architectures of the developed tiles, the transduction mechanism, and the output performances. Finally, a survey of the commercial energy harvesting floors proposed by companies and startups is reported. From the carried-out analysis, we concluded that the piezoelectric transduction mechanism represents the optimal solution for designing smart energy floors, given their compactness, high efficiency, and absence of moving parts

Electromechanical analysis of an adaptive piezoelectric energy harvester controlled by two segmented electrodes with shunt circuit networks

This paper presents an adaptive power harvester using a shunted piezoelectric control system with segmented electrodes. This technique has spurred new capability for widening the three simultaneous resonance frequency peaks using only a single piezoelectric laminated beam where normally previous works only provide a single peak for the resonance at the first mode. The benefit of the proposed techniques is that it provides effective and robust broadband power generation for application in self-powered wireless sensor devices. The smart structure beam with proof mass offset is considered to have simultaneous combination between vibration-based power harvesting and shunt circuit control-based electrode segments. As a result, the system spurs new development of the two mathematical methods using electromechanical closed-boundary value techniques and Ritz method-based weak-form analytical approach. The two methods have been used for comparison giving accurate results. For different electrode lengths using certain parametric tuning and harvesting circuit systems, the technique enables the prediction of the power harvesting that can be further proved to identify the performance of the system using the effect of varying circuit parameters so as to visualize the frequency and time waveform responses

Piezoelectric Energy Harvesting: Enhancing Power Output by Device Optimisation and Circuit Techniques

Energy harvesting; that is, harvesting small amounts of energy from environmental sources such as solar, air flow or vibrations using small-scale (≈1cm 3 ) devices, offers the prospect of powering portable electronic devices such as GPS receivers and mobile phones, and sensing devices used in remote applications: wireless sensor nodes, without the use of batteries. Numerous studies have shown that power densities of energy harvesting devices can be hundreds of µW; however the literature also reveals that power requirements of many electronic devices are in the mW range. Therefore, a key challenge for the successful deployment of energy harvesting technology remains, in many cases, the provision of adequate power. This thesis aims to address this challenge by investigating two methods of enhancing the power output of a piezoelectric-based vibration energy harvesting device. Cont/d

Advance in Energy Harvesters/Nanogenerators and Self-Powered Sensors

This reprint is a collection of the Special Issue "Advance in Energy Harvesters/Nanogenerators and Self-Powered Sensors" published in Nanomaterials, which includes one editorial, six novel research articles and four review articles, showcasing the very recent advances in energy-harvesting and self-powered sensing technologies. With its broad coverage of innovations in transducing/sensing mechanisms, material and structural designs, system integration and applications, as well as the timely reviews of the progress in energy harvesting and self-powered sensing technologies, this reprint could give readers an excellent overview of the challenges, opportunities, advancements and development trends of this rapidly evolving field

Energy Harvesting for Tire Pressure Monitoring Systems

Tire pressure monitoring systems (TPMSs) predict over- and underinflated tires, and warn the driver in critical situations. Today, battery powered TPMSs suffer from limited energy. New sensor features such as friction determination or aquaplaning detection require even more energy and would significantly decrease the TPMS lifetime. Harvesting electrical energy inside the tire of a vehicle has been considered as a promising alternative to overcome the limited lifetime of a battery. However, it is a real challenge to design a system, that generates electrical energy at low velocities while being robust at 200 km/h where radial accelerations up to 20000 m/s2 occur. This work focusses on developing different electromechanical energy transducers that meet the high requirements of the automotive sector. Different approaches are addressed on how the change of acceleration and strain within the tire can be used to provide mechanical energy to the energy harvester. The energy harvester converts the mechanical energy into electrical energy. In this thesis, piezoelectric and electromagnetic transducers are discussed in depth, modelled as electromechanical networks. Since the transducers provide energy in the form of an AC voltage, but sensors require a DC voltage, various common interface circuits are compared, using LTspice and applying method of the stochastic signal analysis. Furthermore, a buck-boost converter concept for the electromagnetic energy harvester is optimized and improved. Experiments on a tire test rig validate the theoretically determined output and confirm that well designed energy harvesters in the tire can generate much more energy than required by an TPMS not only at high velocities but also at velocities as low as 20 km/h

Piezoelectric energy harvesting solutions

This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basics of piezoelectricity and discusses materials choice. The work places emphasis on material operating modes and device configurations, from resonant to non-resonant devices and also to rotational solutions. The reviewed literature is compared based on power density and bandwidth. Lastly, the question of power conversion is addressed by reviewing various circuit solutions

Advanced Energy Harvesting Technologies

Energy harvesting is the conversion of unused or wasted energy in the ambient environment into useful electrical energy. It can be used to power small electronic systems such as wireless sensors and is beginning to enable the widespread and maintenance-free deployment of Internet of Things (IoT) technology. This Special Issue is a collection of the latest developments in both fundamental research and system-level integration. This Special Issue features two review papers, covering two of the hottest research topics in the area of energy harvesting: 3D-printed energy harvesting and triboelectric nanogenerators (TENGs). These papers provide a comprehensive survey of their respective research area, highlight the advantages of the technologies and point out challenges in future development. They are must-read papers for those who are active in these areas. This Special Issue also includes ten research papers covering a wide range of energy-harvesting techniques, including electromagnetic and piezoelectric wideband vibration, wind, current-carrying conductors, thermoelectric and solar energy harvesting, etc. Not only are the foundations of these novel energy-harvesting techniques investigated, but the numerical models, power-conditioning circuitry and real-world applications of these novel energy harvesting techniques are also presented

Printed Energy Storage for Energy Autonomous Flexible Electronics

High-performance and efficient energy storage devices are a necessity for fulfilling the global demand of the growing market of distributed electronics, IoT, mobile electronic devices, electric vehicles, and many more. Supercapacitors and batteries are a priority for energy storage applications. In comparison with batteries, supercapacitors have longer cycle life and higher power density. In some cases, supercapacitors are integrated with batteries to increase electrical performance and efficiency. The aim of the research in this thesis is to develop and scale the design of a sustainable, low-cost, non-toxic, flexible, reliable, and eco-friendly energy storage device for energy-autonomous and distributed electronics platforms. The use of novel materials and a fabricating process for supercapacitor design were essential to achieve the goal of the research. With the use of low specific area electrode ink, the measured capacitance was 3–4 mF in dual cell supercapacitors. Similarly, a PET/Al laminated metal current collector has advantages due to high conductivity, low ESR, and the use of PC electrolyte (2.5 V/cell) to the target voltage range for low power BLE transmission applications. We also developed a PEDOT: PSS based polymer electrolytic capacitor as an alternative to supercapacitors, which demonstrated a way to print flexible capacitors of a few µF. This capacitor was modeled for low frequency applications such as smoothing and filtering. The second focus of the thesis was to perform a reliability study on the energy storage devices. This helps to observe the performance of the device in different situations, from normal to harsh environments. The supercapacitor’s electrical performance was stable over a wide temperature range from -40 °C to 100 °C. The supercapacitors maintain 100% retention for 10,000 bending cycles and a minimum bending radius of 0.41 cm, showing a high degree of flexibility. The device’s performance declined after thermal shock testing due to defects and cracks in the porous electrode because of rapid prolonged temperature cycling between -40 °C and 100 °C. The final part of the thesis is to harvest green energy from ambient surroundings using an organic photovoltaic (OPV) module or a piezoelectric transducer. The maximum indoor energy harvested with an OPV module and stored to the supercapacitor was 39 mJ. On the other hand, with a piezoelectric transducer, the maximum harvested energy was 1.1 mJ and peak power was 11.1 mW. The harvested energy was stored in our printed and flexible storage devices. We also demonstrated that the energy harvested was enough to power an LED driver circuit. Thus, these printed, low-cost, novel, and flexible devices open a door for the field of energy autonomous flexible electronics