Multi-source Energy Harvesting Research Articles

Strategies and Techniques for Powering Wireless Sensor Nodes through Energy Harvesting and Wireless Power Transfer.

The continuous development of internet of things (IoT) infrastructure and applications is paving the way for advanced and innovative ideas and solutions, some of which are pushing the limits of state-of-the-art technology. The increasing demand for Wireless Sensor Nodes (WSNs) able to collect and transmit data through wireless communication channels, while often positioned in locations that are difficult to access, is driving research into innovative solutions involving energy harvesting (EH) and wireless power transfer (WPT) to eventually allow battery-free sensor nodes. Due to the pervasiveness of radio frequency (RF) energy, RF EH and WPT are key technologies with the potential to power IoT devices and smart sensing architectures involving nodes that need to be wireless, maintenance free, and sufficiently low in cost to promote their use almost anywhere. This paper presents a state-of-the-art, ultra-low power 2.5 W highly integrated mixed signal system on chip (SoC), for multi-source energy harvesting and wireless power transfer. It introduces a novel architecture that integrates an ultra-low power intelligent power management, an RF to DC converter with very low power sensitivity and high power conversion efficiency (PCE), an Amplitude-Shift-Keying/Frequency-Shift-Keying (ASK/FSK) receiver and digital circuitry to achieve the advantage to cope, in a versatile way and with minimal use of external components, with the wide variety of energy sources and use cases. Diverse methods for powering Wireless Sensor Nodes through energy harvesting and wireless power transfer are implemented providing related system architectures and experimental results.

Multisource Energy Harvesting System for a Wireless Sensor Network Node in the Field Environment

This paper presents the design, implementation, and characterization of a hardware platform applicable to a self-powered wireless sensor network (WSN) node. Its primary design objective is to devise a hybrid energy harvesting system to extend the operational lifetime of WSN node after they are deployed in the field environment. Besides the implementation of optimal components (microcontroller, sensor, radio frequency (RF) transceiver, and others) to achieve the lowest power consumption, it is also necessary to consider the sources of energy instead of the frequent recharging or replacement of batteries. Therefore, the platform incorporates a multisource energy harvesting module to collect energy from the surrounding environment, including wind, solar radiation, and thermal energy. The platform also includes an energy storage module through a super-capacitor, RF transceiver module, and the primary microcontroller module. Experimental results showed that the WSN node system with appropriate integration will reserve sufficient energy and meet the long-term power supply requirements of the WSN node without batteries in the field environment. The experimental results and empirical measurements taken over nine days demonstrated that the average daily generating capacity was 7805.09 J, which is far more than the energy consumption of the WSN node (about 2972.88 J).

Hybrid, Multi-Source, and Integrated Energy Harvesters

Energy harvesting is one of the most rapidly growing of the emerging technologies. This field has arrived at the hybrid and multi-source era, where hybrid structures and novel materials are able to boost the energy conversion efficiency and/or make the harvesters capable of benefitting from multiple energy sources simultaneously. Such hybrid and multi-source energy harvesters have not frequently been reviewed in the past, potentially because of the small number of publications compared to that of their single-source and individual counterparts. However, as their number is becoming larger, it is now necessary to give sufficient and frequent reviews of developments in the field. Furthermore, an increasing number of developed energy harvesters are moving out of the laboratory into industrial markets. In practice, energy harvesters need to be integrated with energy storage and/or end users such as sensors and wireless sensor networks. Therefore, the harvester-storage and harvester-sensor integration systems also need to be reviewed frequently. This mini-review includes works reported in the first half of 2018 and provides a timely update to the published review. It focuses on the above-mentioned hybrid and multi-source energy harvesters as well as on integrated harvesters, energy storage systems and end users (e.g. sensors), including CMOS (complementary metal-oxide-semiconductor) technology-based harvesters and systems.

Boosting Photovoltaic Output of Ferroelectric Ceramics by Optoelectric Control of Domains.

Photo-ferroelectric single crystals and highly oriented thin-films have been extensively researched recently, with increasing photovoltaic energy conversion efficiency (from 0.5% up to 8.1%) achieved. Rare attention has been paid to polycrystalline ceramics, potentially due to their negligible efficiency. However, ceramics offer simple and cost-effective fabrication routes and stable performance compared to single crystals and thin-films. Therefore, a significantly increased efficiency of photo-ferroelectric ceramics contributes toward widened application areas for photo-ferroelectrics, e.g., multisource energy harvesting. Here, all-optical domain control under illumination, visible-range light-tunable photodiode/transistor phenomena and optoelectrically tunable photovoltaic properties are demonstrated, using a recently discovered photo-ferroelectric ceramic (K0.49Na0.49Ba0.02)(Nb0.99Ni0.01)O2.995. For this monolithic material, tuning of the electric conductivity independent of the ferroelectricity is achieved, which previously could only be achieved in organic phase-separate blends. Guided by these discoveries, a boost of five orders of magnitude in the photovoltaic output power and energy conversion efficiency is achieved via optical and electrical control of ferroelectric domains in an energy-harvesting circuit. These results provide a potentially supplementary approach and knowledge for other photo-ferroelectrics to further boost their efficiency for energy-efficient circuitry designs and enable the development of a wide range of optoelectronic devices.

Energy Management Integrated Circuit for Multi-Source Energy Harvesters in WBAN Applications

This paper presents an energy management integrated circuit for multiple energy harvesters in wireless body area network applications. The electrical power acquired from a single energy harvester around a human body is limited to micro watts, which is insufficient to drive a wearable electronic device. To increase this small amount, the energy from a number of harvesters has to be combined. By combining the energy from multiple distributed harvesters, each one producing negligible energy, significant energy for wearable devices can be obtained. In designing an energy management circuit for a wearable device, there are two issues to be resolved. The first is related to the power consumption of the circuit, and the second issue is related to the methods needed to manage the wide range of power that occurs as the energy input changes during harvesting. In this paper, an energy management circuit that resolves the two issues above is described. The circuit was integrated using 0.13 µm Taiwan Semiconductor Manufacturing Company complementary metal-oxide-semiconductor technology. The energy management circuit is designed to combine up to three sources of harvested energy with more than 90% operating efficiency over the entire power range of the energy harvested.

Energy Harvesting Research: The Road from Single Source to Multisource.

Energy harvesting technology may be considered an ultimate solution to replace batteries and provide a long-term power supply for wireless sensor networks. Looking back into its research history, individual energy harvesters for the conversion of single energy sources into electricity are developed first, followed by hybrid counterparts designed for use with multiple energy sources. Very recently, the concept of a truly multisource energy harvester built from only a single piece of material as the energy conversion component is proposed. This review, from the aspect of materials and device configurations, explains in detail a wide scope to give an overview of energy harvesting research. It covers single-source devices including solar, thermal, kinetic and other types of energy harvesters, hybrid energy harvesting configurations for both single and multiple energy sources and single material, and multisource energy harvesters. It also includes the energy conversion principles of photovoltaic, electromagnetic, piezoelectric, triboelectric, electrostatic, electrostrictive, thermoelectric, pyroelectric, magnetostrictive, and dielectric devices. This is one of the most comprehensive reviews conducted to date, focusing on the entire energy harvesting research scene and providing a guide to seeking deeper and more specific research references and resources from every corner of the scientific community.

Multi-Source Energy Harvesting and Storage for Floating Wireless Sensor Network Nodes With Long Range Communication Capability

Wireless sensor networks are widely used for environmental monitoring in remote areas. They are mainly composed of wireless sensor nodes, usually powered by batteries with limited capacity, but are expected to communicate in long range and operate for extended time periods. To overcome these limitations, many energy harvesting techniques are proposed to power wireless nodes for prolonged operation, whereas multihop techniques are utilized to extend the communication range. In this paper, a novel floating device with multisource energy harvesting technology that can be used as a wireless sensor node is proposed. The long range communication between wireless sensor nodes and a gateway is established through LoRa technology. In addition to conventional solar panels, an energy harvesting technique based on thermoelectric generators exploiting thermal differences created between water surface and materials exposed to sunlight is proposed. Energy generated from photovoltaic and thermoelectric generators is combined to power the wireless sensor node. This floating device consumes 6.6216 Wh per day when used as a wireless sensor node for the collection and transmission of environmental data. The sensor node can operate on a water surface for at least 9.6 days when it is not exposed to sunlight. During a sunny day, the floating device can harvest 8.375 Wh from solar panels and 0.425 Wh from thermoelectric generation. In other words, the floating device harvests sufficient energy to be self-sustaining during sunny days.

An integrated multi-source energy harvester based on vibration and magnetic field energy

In this paper, an integrated multi-source energy harvester (IMSEH) employing a special shaped cantilever beam and a piezoelectric transducer to convert vibration and magnetic field energy into electrical energy is presented. The electric output performance of the proposed IMSEH has been investigated. Compared to a traditional multi-source energy harvester (MSEH) or single source energy harvester (SSEH), the proposed IMSEH can simultaneously harvest vibration and magnetic field energy with an integrated structure and the electric output is greatly improved. When other conditions keep identical, the IMSEH can obtain high voltage of 12.8V. Remarkably, the proposed IMSEHs have great potential for its application in wireless sensor network.

A Game Changer: A Multifunctional Perovskite Exhibiting Giant Ferroelectricity and Narrow Bandgap with Potential Application in a Truly Monolithic Multienergy Harvester or Sensor.

An ABO3 -type perovskite solid-solution, (K0.5 Na0.5 )NbO3 (KNN) doped with 2 mol% Ba(Ni0.5 Nb0.5 )O3-δ (BNNO) is reported. Such a composition yields a much narrower bandgap (≈1.6 eV) compared to the parental composition-pure KNN-and other widely used piezoelectric and pyroelectric materials (e.g., Pb(Zr,Ti)O3 , BaTiO3 ). Meanwhile, it exhibits the same large piezoelectric coefficient as that of KNN (≈100 pC N-1 ) and a much larger pyroelectric coefficient (≈130 µC m-2 K-1 ) compared to the previously reported narrow-bandgap material (KNbO3 )1-x -BNNOx . The unique combination of these excellent ferroelectric and optical properties opens the door to the development of multisource energy harvesting or multifunctional sensing devices for the simultaneous and efficient conversion of solar, thermal, and kinetic energies into electricity in a single material. Individual and comprehensive characterizations of the optical, ferroelectric, piezoelectric, pyroelectric, and photovoltaic properties are investigated with single and coexisting energy sources. No degrading interaction between ferroelectric and photovoltaic behaviors is observed. This composition may fundamentally change the working principles of state-of-the-art hybrid energy harvesters and sensors, and thus significantly increases the unit-volume energy conversion efficiency and reliability of energy harvesters in ambient environments.

Optimization Design and Simulation of a Multi-Source Energy Harvester Based on Solar and Radioisotope Energy Sources.

A novel multi-source energy harvester based on solar and radioisotope energy sources is designed and simulated in this work. We established the calculation formulas for the short-circuit current and open-circuit voltage, and then studied and analyzed the optimization thickness of the semiconductor, doping concentration, and junction depth with simulation of the transport process of β particles in a semiconductor material using the Monte Carlo simulation program MCNP (version 5, Radiation Safety Information Computational Center, Oak Ridge, TN, USA). In order to improve the efficiency of converting solar light energy into electric power, we adopted PC1D (version 5.9, University of New South Wales, Sydney, Australia) to optimize the parameters, and selected the best parameters for converting both the radioisotope energy and solar energy into electricity. The results concluded that the best parameters for the multi-source energy harvester are as follows: Na is 1 × 1019 cm−3, Nd is 3.8 × 1016 cm−3, a PN junction depth of 0.5 μm (using the 147Pm radioisotope source), and so on. Under these parameters, the proposed harvester can achieve a conversion efficiency of 5.05% for the 147Pm radioisotope source (with the activity of 9.25 × 108 Bq) and 20.8% for solar light radiation (AM1.5). Such a design and parameters are valuable for some unique micro-power fields, such as applications in space, isolated terrestrial applications, and smart dust in battlefields.

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.

Maximum power point tracking for optimizing energy harvesting process

There has been a growing interest in using energy harvesting techniques for powering wireless sensor networks. The reason for utilizing this technology can be explained by the sensors limited amount of operation time which results from the finite capacity of batteries and the need for having a stable power supply in some applications. Energy can be harvested from the sun, wind, vibration, heat, etc. It is reasonable to develop multisource energy harvesting platforms for increasing the amount of harvesting energy and to mitigate the issue concerning the intermittent nature of ambient sources. In the context of solar energy harvesting, it is possible to develop algorithms for finding the optimal operation point of solar panels at which maximum power is generated. These algorithms are known as maximum power point tracking techniques. In this article, we review the concept of maximum power point tracking and provide an overview of the research conducted in this area for wireless sensor networks applications.

Diphase: Characterizing Packet Delay in Multi-Source Energy Harvesting Systems

We consider multi-source energy harvesting communication systems, where the energy harvested from two independent processes is used for the transmission of the data packets. The data packets arrive randomly and wait in a queue for accumulation of sufficient energy and for service completion of previously arrived packets. Thus, the data queue dynamics are influenced jointly by the energy arrival process, the data arrival process, and the data service process. This coupling between the data and energy queues makes an exact system analysis extremely hard, and has led researchers to resort to either computationally intensive numerical solutions or to make simplifying approximations. In this paper, we employ Diphase , a two phase queueing formulation, which decouples the wait stages for the energy arrival process and the service process, to derive closed-form expressions for the average packet delay and the probability of data packet loss due to buffer overflow. These expressions are shown to be exact when the service time is negligible, and robust for a relatively wide range of values of the average service time. We show that these expressions are useful in selecting system design parameters, which maximize the throughput while meeting the required quality of service constraints.

A multisource energy harvesting utilizing highly efficient ferroelectric PMN-PT single crystal

This paper demonstrates a multi-source energy harvester that is able to utilize simultaneously both piezoelectric and pyroelectric effects in lead magnesium niobate-lead titanate (PMN-PT) single crystal. The paper presents a study of PMN-PT single crystal with a (67:33) composition grown in our laboratory via a vertical gradient freeze method without any flux. The performance of the piezoelectric and pyroelectric energy harvester using unimorph device structure was evaluated via modeling and experiment. The theoretical study was implemented based on a distributed parameter electromechanical model and the modelling procedure was approximated using finite element analysis to predict the electromechanical behavior of the harvester. The maximum power density at a resonance frequency of 50 Hz and optimum resistance of 2 MΩ was 16.7 nW/(g2 cm3) under a 1 g acceleration of vibration. The measured values of electrical output parameters were in good agreement with theoretical and modelling results using MATLAB and COMSOL Multiphysics, respectively. By using the pyroelectric effect along with the piezoelectric effect, the output voltage of the energy harvester was found to be enhanced at the optimum resistance and specific frequency values. It was noticed that the output voltage was increased monotonically with temperature-difference (ΔT) and reaches up to 180 % of its original value under temperature difference of 1.7 °C at a frequency value of 49 Hz.

DTMOS-Based Pulse Transformer Boost Converter With Complementary Charge Pump for Multisource Energy Harvesting

An energy-harvesting system that accommodates both discrete-time or continuous-time energy sources simultaneously is presented. The core dc–dc converter is a pulse transformer boost converter using dynamic threshold MOS transistor that self-starts at 36 mV-input voltage and generates bipolar output voltages up to ±2.5 V. Employing the dynamic body bias technique to the boost converter power transistor improves power efficiency at sub-300-mV input voltages up to two times over the identical transistor in a conventional configuration. At large harvested power, the source-to-body diode of the power transistor functions as an input voltage limiter. Dynamic threshold MOSFET (DTMOS) also increases transistor saturation current and output power compared to conventional transistors at similar input voltage. Instead of using a linear shunt regulator, excess power is dissipated by internal loss of a bipolar-clocked cross-coupled charge pump. An on-chip voltage-controlled oscillator, which generates clock frequency in proportion to the harvested power, and a unipolar-to-bipolar level shifter are included to drive the charge pump designed. The circuit prototypes are fabricated by using the UMC 0.13- $\mu\mbox{m}$ CMOS process with the triple-well option.

Area Model and Dimensioning Guidelines of Multisource Energy Harvesting for Nano–Micro Interface

Multisource energy harvesters are a promising, robust alternative to power the future Internet of Nano Things (IoNT), since the network elements can maintain their operation regardless of the fact that one of its energy sources might be temporarily unavailable. Interestingly, and less explored, when the energy availability of the energy sources present large temporal variations, combining multiple energy sources reduce the overall sparsity. As a result, the performance of a multiple energy harvester powered device is significantly better compared to a single energy source even if they harvest the same amount of energy. In this context, a framework to model and characterize the area for multiple source energy harvesting (EH) powered systems is proposed. This framework takes advantage of this improvement in performance to provide the optimal amount of energy harvesters, the requirements of each energy harvester, and the required energy buffer capacity, such that the overall area or volume is minimized. On top of these results, self-tunable energy harvesters are explored as a solution and compared to multisource EH platforms. As the results show, by conducting a joint design of the energy harvesters and the energy buffer, the overall area or volume of an EH powered device can be significantly reduced.

Self-Powered Wireless Sensor Applied to Gear Diagnosis Based on Acoustic Emission

Advanced sensing strategies in the industrial sector are becoming a valued technological answer to increase the performance and competitiveness. The development of enhanced sensing solutions considering both technology and monitoring requirements is, nowadays, subject of concern in the industrial maintenance field. In this context, this paper presents a novel self-powered wireless sensor applied to condition monitoring of gears. The proposed sensor is based on a modular architecture, offering multipoint sensing, local wireless communication, multisource energy harvesting, and embedded diagnosis algorithm for mechanical fractures detection based on acoustic emission analysis. The developments are complemented by means of a remote management interface, from which the user can configure the functionalities of the sensors, visualize the network status as well as analyze the diagnosis evolution. The sensor performance, in terms of power consumption and fault detection, has been analyzed by means of experimental results.

A Nanocurrent Power Management IC for Multiple Heterogeneous Energy Harvesting Sources

This paper presents a fully autonomous power converter IC for energy harvesting from multiple and multitype sources, such as piezoelectric, photovoltaic, thermoelectric, and RF transducers. The converter performs an independent self-adapting input power tracking process for each source. The peak power conversion efficiency measured during single-source operation is 89.6%. With all sources enabled, the intrinsic current consumption is as low as 47.9 nA/source. A self-starting battery-less architecture has been implemented in a 0.32-μm STMicroelectronics BCD technology with a 2142 μm × 2142 μm die area. The IC only requires a single-shared inductor and an external storage capacitor for the basic working configuration. With respect to other multisource energy harvesters, this design specifically introduces a series of nanopower design techniques for extreme minimization of the intrinsic consumption during operation. The small chip size combined with the limited number of required external component, the high conversion efficiency, and the state-of-the-art intrinsic nanocurrent consumption make the IC suitable for many critical applications with very limited available power, such as wearable devices or unobtrusive wireless sensor networks.

On the comparison of energy sources: Feasibility of radio frequency and ambient light harvesting

With growing interest in multi source energy harvesting including integrated microchips we propose a comparison of radio frequency (RF) and solar energy sources in a typical city. Harvesting devices for RF and solar energy will be competing for space of a compact micro or nano device as well as for orientation with respect to the energy source. This is why it is essential to investigate importance of every source of energy and make a decision whether it will be worthwhile to include such harvesters. We considered theoretically possible irradiance by RF signal in different situations, typical for the modern urban environment and compared it with ambient solar energy sources available through the night, including moonlight.Our estimations show that solar light energy dominates by far margin practically all the time, even during the night, if there is a full moon in the absence of clouds. At the same time, in the closed compartments or at the new moon RF harvesting can be beneficial as a source of “free” energy.

Multi-source Energy Harvesting System for Underwater Wireless Sensor Networks

Due to increase in its wide range of applications, underwater wireless sensor nodes are gaining importance and there is need to develop reliable underwater sensor networks. Major hindrance to performance of underwater networks is power supply to nodes. The ultimate aim in designing energy harvesters is to provide continuous power supply for node system in adequate environmental energy conditions. To achieve continual, reliable and efficient power supply for underwater sensors, we propose multi source energy harvester system which manages energies from piezoelectric harvesting and microbial fuel cell. Analytical expressions are obtained for proposed system and are validated using extensive simulations.