Hybrid Energy Harvesting Research Articles

A piezoelectric and electromagnetic hybrid energy harvester based on two-stage magnetic coupling

Traditional piezoelectric energy harvesters cannot adapt to environmental energy with low frequency, wideband, and randomness because of the narrow working bandwidth. The introduction of magnetic coupling can improve the narrow-band characteristics of piezoelectric energy harvesting structures. To explore more efficient broadband methods, this paper designs a piezoelectric and electromagnetic hybrid energy harvester (PEEH) based on two-stage magnetic coupling to realize the expansion of piezoelectric energy harvesting bandwidth. In this paper, the magnetic pole alternating frequency is changed and the output of the structure is tested, and the operating frequency bands under different alternating frequencies are compared according to the test results. It can be seen from the experimental results that the output performance of the structure is obviously improved by increasing the AC frequency of the magnetic pole while reducing the optimal frequency point of the structure. When the number of magnets in the rotor magnet array is 6, increasing the pole alternating frequency can effectively improve the output performance of the electromagnetic unit when the rotor speed is low, and can also increase the maximum output voltage and energy harvest bandwidth of the piezoelectric unit by 189% and 150%, respectively. Therefore, by increasing the alternating frequency of magnetic poles, the output voltage of the structure can be improved, and the bandwidth of the structure can be broadened.

A hybrid energy harvesting approach for transmission lines based on triboelectric nanogenerator and micro thermoelectric generator

To effectively detect faults in transmission lines, monitoring the operating status of these lines is imperative. However, providing power to monitoring devices for transmission line status presents a significant challenge. In this research, a hybrid energy harvesting approach based on micro thermoelectric generator (MTEG) and triboelectric nanogenerator (TENG) is proposed, and a theoretical model for MTEG-TENG hybrid energy harvesting is established. This study develops an integrated energy harvesting prototype, which incorporates oscillating-TENG (O-TENGs), MTEGs, and a power management control unit. This prototype not only harvests energy from the vibrations of transmission lines but also converts the lines thermal energy into electricity. The Experiment results show that the maximum open-circuit voltages of O-TENG and MTEG reach 80.3 V and 1.094 V, respectively. Compared to a single MTEG energy harvesting device, the prototype of the MTEG-TENG hybrid energy harvesting device demonstrates a 5.36% improvement in energy harvesting and battery charging performance. Consequently, this approach achieves self-powered monitoring with excellent stability and lower manufacturing costs. It provides an efficient and durable power approach for transmission line status monitoring devices.

A piezo-electromagnetic hybrid multi-directional vibration energy harvester in freight trains

Rail freight systems are widely acknowledged for their operational efficiency across various nations. However, a prevailing limitation lies in the absence of power supply within standard freight wagons, impeding the installation of essential sensors to monitor train operation. This paper provides an innovative solution to this issue, where a novel device is developed to harvest vibration energy from freight trains to power operational condition monitoring sensors. The proposed device integrates a piezoelectric energy harvester with an electromagnetic counterpart, utilizing a spring-mass structure to capture vibration energy and transfer it to cantilever beams through magnetic coupling. A cantilever beam with variable width and a distinctive “checkmark” shape is employed to ensure even stress distribution to enhance piezoelectric material efficiency. The optimal spatial configuration between magnets and coils, as well as inter-magnet spacing, is determined through finite element analysis and empirical testing. Experimental results under the excitation with a frequency of 9.5 Hz and a vertical amplitude of 2 mm show the hybrid harvester can generate a maximum power of 3.276 mW. This hybrid energy harvesting system has the potential to provide dependable power to electronic components, including temperature sensors and accelerometers, crucial for monitoring rail freight train operations.

Efficiency Analysis of Hybrid Extreme Regenerative with Supercapacitor Battery and Harvesting Vibration Absorber System for Electric Vehicles Driven by Permanent Magnet Synchronous Motor 30 kW

This research presents an approach to the hybrid energy harvesting paradigm (HEHP) based on suspended energy harvest. It uses a harvesting vibration absorber (HVA) with an SC/NMC-lithium battery hybrid energy storage paradigm (SCB-HESP) equipped regenerative braking system (SCB-HESP-RBS) for electric vehicles 2 tons in gross weight (MEVs) driven by a 30 kW permanent magnet synchronous motor (PMSM). During regenerative braking, the ANN mechanism controls the RBS to adjust the switching waveform of the three-phase power inverter, and the braking energy transfers to the energy storage device. Additionally, a supercapacitor (SC) equipped with HVA can absorb energy from vehicle vibrations and convert it into electrical energy. The energy-harvesting efficiency of MEV based on SCB-HESP-RBS using HVA suspended energy harvesting enhances the efficiency maximum to 50.58% and 15.36% in comparison to MEV with only-HVA and SCB-HESP-RBS, respectively. Further, the MEV with SCB-HESP-RBS using HVA has a driving distance of up to 247.34 km (22.5 cycles) when compared with SCB-HESP-RBS (214.40 km, 19.5 cycles) and only-HVA (164.25 km, 15 cycles).

A broadband hybrid blue energy nanogenerator for smart ocean IoT network

Blue energy represents a crucial renewable energy resource; however, its development has been limited by the low and variable frequency characteristics of sea waves. In this study, we present a novel approach, wherein a spring pendulum coupled hybrid energy harvester (SPC-HEH) is employed to address these limitations. The SPC-HEH integrates two electromagnetic generators (EMGs), two piezoelectric nanogenerators (PENGs), and two multilayer-structured triboelectric nanogenerators (TENGs) into a vessel, enabling efficient wave energy harvesting. Notably, the integration of the lightweight PENG and TENG with the heavy EMG not only enhances the water wave energy harvesting capability of SPC-HEH but also optimizes its spatial utilization efficiency. Additionally, owing to the spring pendulum, the SPC-HEH is capable of simultaneously harnessing the wave kinetic energy of horizontal and vertical directions and realize the decoupling of vertical energy capture from horizontal energy capture. Remarkably, owing to its precise geometric design and efficient space utilization, the SPC-HEH achieves an impressive peak power density of 82.4 Wm−3. Finally, we demonstrate the practical applicability of the SPC-HEH by integrating it with a circuit as a self-powered ocean buoy for real-time monitoring of ocean temperature, wave frequency, ocean turbidity and other information. The remarkable potential of this system for integration into self-powered smart ocean IoT networks holds significant promise for advancing marine research and environmental monitoring capabilities.

MoS2@ZIF-8-based aerogel with multiscale biomimetic structure achieving all-day desalination and wastewater purification

In emerging freshwater generation strategy, solar driven evaporation technology has been brought into focus owing to its non-pollution and facile facilities. However, maintaining high freshwater yield remains a challenge under natural circumstances. Herein, MoS2@ZIF-8-based aerogel featuring a lotus root hourglass-shaped structure (denoted as LMZA) for efficient freshwater production via hybrid energy harvesting is ingeniously devised. After being integrated with metallic 1 T phase MoS2 and a vertically aligned porous structure, LMZA not only achieves an outstanding evaporation rate at different incident angles and intensities, but also utilizes wind or environmental energy for evaporation. More importantly, the proposed LMZA also achieved a fast evaporation rate of 8.47 kg m-2h−1 under 4.0 m s−1 without solar irradiation, which fully eliminated the impact of solar intermittency. Afterward, LMZA with a cross-scale hierarchical structure for desalination exhibits an evaporation rate of up to 2.08 kg m-2h−1 under one sun irradiation in 20 wt% brine, and possesses exceptional adaptability and stability. Besides, another advantage of LMZA is the effective purification of cadmium-containing wastewater through water evaporation and in situ adsorption. The removal efficiency is 74 % under one sun irradiation, and the condensed water with undetected Cd(II) heavy metal ions was obtained. More importantly, combined with ambient factors such as wind and ambient temperature in the natural environment, the home-made device achieves all-day freshwater generation with a daily yield of 27.08 kg m−2. The investigation of the device and LMZA pioneers a novel design concept for high yield freshwater generation in practical applications.

Photothermally-activated piezo-pyroelectric multifunctional hybrid energy harvester for motion sensing and thermal therapy

Herein a piezoelectric-pyroelectric hybrid energy harvester (PPEH) is developed for the simultaneous conversion of mechanical and thermal energy into electrical power. In this work, poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) is selected as the polymer matrix due to its flexibility, light weight, easy processing, and biocompatibility, while nanoparticles of a photothermal poly(2-ethylaniline) (PEAn) are added as a dopant to enhance the piezoelectric output and simultaneously endow the composite material with pyroelectric properties. As a result, the output voltage under solar irradiation is enhanced by up to 3.26 times relative to that of an energy harvester based on the piezoelectric property alone. Moreover, the application of this dual-functional material is demonstrated in a wearable electronic device that is capable of detecting motion in diverse joint regions and providing thermal therapy, suggesting the potential to function as both a sensor and a therapeutic tool, thereby demonstrating its viability as a multifunctional wearable device.

Nonlinear Model and Experimental Verification of Bistable Hybrid Energy Harvester Based on Wheel–Rail Vibration

Nonlinear Model and Experimental Verification of Bistable Hybrid Energy Harvester Based on Wheel–Rail Vibration

C-Slot Circular Polarized Antenna for Hybrid Energy Harvesting and Wireless Sensing

This paper presents a new hybrid energy harvesting on electromagnetic solar for wireless energy harvesting of ambient from sensors of low-power devices. The axial ratio (AR) requirements produce Left-Hand Circular Polarization (LHCP) and Right-Hand Circular Polarization (RHCP) and simultaneously produce a 90-degree phase difference during energy harvesting, adopting a new design in designing a dual-feed broadband circular polarized (CP) antenna. To get the frequency band 2.3–2.4 GHz, we propose a C-Slot antenna with a circular patch dual feed. To estimate the diversity of the phase and magnitude output of the feed configuration under AR value, we used a 50 Ohm feed network output of the characteristic analysis for a dual feed CP antenna. An Axial ratio frequency range of less than 3 dB is achieved using polarization analysis with different branch channel couplers. To produce a DC output voltage, a high-frequency rectifier circuit embedded with a thin-film solar cell on the antenna is then connected to two T-junction power divider rectifiers, resulting in a high-efficiency design. A complete system-level analysis will include multiple signal classification methods of powered ambient RF energy using a wireless energy harvesting array that proposes a compact structure and demonstrates optimal configuration. Reliable operation in typical indoor environments indicates a self-contained sensor Node. Therefore, it has significant implications for powering small electronics and wireless sensor applications independently of the IoT Network or real implementation telecommunications industry.

Numerical energy evaluation of an optimized hybrid energy harvesting system (CPV-TEG) considering the effects of solar tracking

Currently, the energy demand at a global level is accelerated, and the use of non-renewable energies increases the problems related to global warming. Solar technologies, mainly photovoltaics, have been used as an alternative, but conversion efficiency is still low. Hybrid generation systems, which integrate photovoltaic and thermoelectric technologies, seek to provide a solution to efficiency and high costs per area unit. These systems need high tracking precision to concentrate solar energy, which requires robotic tracking systems, which generate energy waste due to the tracking action. The studies and developments do not contemplate in their analysis the losses due to tracking or the precision required by the optical concentration element. The present research develops a novel methodology for the design of optimized hybrid energy harvesting systems, integrating the concentrated photovoltaic and thermoelectric generator technologies and including the effects of solar tracking in the energy sense. In addition, a process for the numerical evaluation of hybrid systems is presented, considering thermal and tracking simulations to estimate the global energy balance. Consequently, the design methodology and numerical evaluation are implemented, comparing three concentration configurations. Additionally, a focus control device is designed for a high concentration index and evaluated. The mean total electrical efficiency of the hybrid system is 40.6763%, 38.84%, 13.3439%, and 35.0484%, respectively. With global gain estimates of 189.48 Wh, 201.83 Wh, 47.43 Wh, and 141.91 Wh. Finally, the results are compared with other developments, concluding that the hybrid system has high energy production. In conclusion, the proposal increases the overall performance of hybrid energy harvesting systems, allowing the development of future research regarding novel concentration devices, cooling methods, harvesting systems, and absorbing designs, among other innovations in more realistic energy evaluation terms.

Numerical study of a synergistic hybrid energy harvesting system for bladeless wind turbines

Using energy of the fluid flow over an oscillating vertically-mounted flexible cylinder, as a representative configuration of bladeless wind turbines (BWTs), has recently attracted wide attention in the fluid mechanics community. In this paper, the fluid–structure interactions of a novel BWT-based hybrid piezo-electromagnetic energy harvesting system have been numerically studied in the vortex-induced-vibration (VIV) lock-in region by using the Reynolds Averaged Navier-Stokes (RANS) equations with the SST k-ω turbulence model. It is found that by implementing the electromagnetic (EMT) and/or piezoelectric (PVDF) transducers, the lock-in region becomes wider (up to 33% for the hybrid system) while being shifted to the higher Reynolds number (Re) range. Also, the dimensionless BWT cross-flow tip displacement amplitude (Yamp∗) is seen to reduce about 20%, 70%, and 70% by using the single-alone EMT-based, single-along piezo-based, and the hybrid harvester, respectively, which can potentially lead to substantial improvements in the fatigue life of the system Furthermore, the synergetic action of the hybrid system is observed to cause an overall increase in the harvested energy levels besides broadening of the associated range, as each of energy harvesting components appears to produce higher output power as compared to the respective single-alone system. In other words, up to 260% increase (100% increase) in the overall harvested energy level and up to 300% increase (60% increase) in the harvestable Re range with respect to the single-alone piezo-based (EMT-based) system are obtained, in which about 50% (about 10%) synergetic effects can be associated with the EMT- and piezo-based transducers, respectively.

Autonomous self-healing hybrid energy harvester based on the combination of triboelectric nanogenerator and quantum dot solar cell

Realization of multi-source energy harvesting with one single device would maximize power output. Thus, it is emerging as a promising strategy towards renewable energy generation and has attracted worldwide attention in the past decades. Capable of capturing mechanical energy that is ubiquitous in the ambient environment, triboelectric nanogenerator (TENG) has been considered a novel yet effective source towards next-generation energy harvesting. In this work, a flexible hybrid energy harvester (HEH) is developed via the rational integration of autonomous self-healing TENG and high bending-stable lead sulfide quantum dot (PbS QD) solar cell, enabling independent electricity generation by two different mechanisms. The single-electrode mode TENG component with self-healing is realized by a polydimethylsiloxane/Triton X-100 (PDMS/TX100) mixture as the dielectric layer and the shared gold (Au) electrode, which generates 0.39 µA of output current (Iout), 24.6 V of output voltages (Vout), 15.4 nC of transfer charges (Qsc), and 7.80 mW m−2 of output power peak density. The thin-film solar cell component is based on a PbS QD layer as the light absorber with a planar structure fabricated under low-cost and compatible conditions, achieving 22.8 mA cm−2 of short-circuit current density (Jsc) and 4.92% of power conversion efficiency (PCE). As a proof of concept, an electronic watch is successfully powered by harnessing ambient mechanical and solar energy with a hybridized energy cell. This approach will offer more opportunities to construct a versatile platform towards remote monitoring and smart home systems.

Energy Harvesting Scheme for Dynamic Spectrum Access using Cognitive Radio Technology

In this paper, a hybrid energy harvesting strategy is proposed that maximizes energy collection by utilizing Radio Frequency (RF) energy obtained from both Primary Users (PU) and Secondary Users (SU), and accurately detecting their presence or absence in the channel. Specifically, it examines the captured energy vis-à-vis the planned transmission power, guaranteeing a wise deployment of available resources. The proposed approach efficiently incorporates external energy sources to fill up any gaps in energy availability, thus, bypassing the restrictions imposed by battery lifespans. The efficacy of this proposed strategy is carefully examined using large numerical simulations, which provide persuasive proof of its superiority over conventional methods.

Design and development of a novel Four-Links rotational hybrid Energy-Harvesting suspension system compatible with conventional suspension technologies

This study introduces a novel rotational Energy Harvesting Shock Absorber (EHSA), specifically designed for use alongside existing vehicle suspension systems. Addressing issues faced by standalone EHSAs, this design incorporates a four-bar mechanism coupled to a rotary energy recovery system. The proposed EHSA system, dubbed the FL-EHSA (Four Links Energy Harvesting Shock Absorber), is based on link connections and is highly versatile. It has the potential to significantly improve vehicle efficiency by harnessing energy usually wasted by traditional shock absorbers. Using a geometric definition process influenced by various factors such as vehicle suspension type and commercial availability of components, the FL-EHSA system was modeled, and bench-tested to validate the system’s energy recovery potential and performance. The movement of the mechanism was analyzed to achieve the target damping value matching the value of a conventional suspension and to maximize efficiency through DOE analysis and to avoid mechanical locking (singular positions). It explains the effect of backlash in mechanical components through simulation and highlights the importance of using dedicated gearboxes for energy recovery. In addition, this work highlights the untapped potential of four-bar mechanisms in automotive energy recovery applications. Moreover, the proposed design is easily integrated into any vehicle, making it a promising solution for EHSA systems.

Energy generation through a hybrid energy harvester under random excitation

This manuscript analyses a multi-frequency based coupled piezo-electromagnetic hybrid vibration energy harvester. Most of the energy harvesting devices discussed in the literature are based on the assumption that the base excitation is harmonic. However, in general, energy harvesting devices are deployed in an ambient environment, which is random in nature. Hence, in this regard, the manuscript discusses the power harvesting capabilities of the hybrid energy harvester under random base excitation using analytical and experimental studies. Acceleration with band limited Gaussian noise has been provided as an input to the base of the harvester. Comparative studies are also made to understand the performance of the hybrid harvester over conventional standalone piezoelectric and electromagnetic harvesters under the same support excitation. Thus, the novelty of the present work is to analyse a novel design of a hybrid harvester to improve harvesting performance across a wide range of frequencies under random base excitation compared to conventional harvesters. The results demonstrate that the proposed hybrid energy harvester can yield sufficient power over a wide range of frequencies. In addition, parametric studies have also been performed to characterize the system parameters in order to enhance the performance of the harvester. Studies show that the harvested power can be enhanced by maximizing the values of mass ratio, frequency ratio, non-dimensional electromechanical coupling coefficient and minimizing the values of structural damping ratios. Finally, practical applications of the proposed device have also been reported.

Research on a rotary piezoelectric energy harvester based on movable magnets

A hybrid energy harvester (HEH) is designed using a movable magnet to harvest the mechanical energy for rotational motion. One movement of the movable magnet can generate electricity from piezoelectric nanogenerators (PENG) and electromagnetic generators (EMG), improving the energy conversion efficiency of HEH. The main factors affecting the motion characteristics of active magnets (number of magnets and magnet diameter) are illustrated through theoretical modeling and simulation, and the voltage characteristics of EMG and vibration characteristics of PENG are analyzed. According to the main factors affecting the motion characteristics, the experimental testing system was set up. The results show that the voltage of PENG and EMG can be up to 6.55 V and 1.37 V, respectively as the magnet diameter is 10 mm and the number of magnets is 5. The maximum power of PENG is 2.4 mW at 30 kΩ, and the power of EMG is 0.49 mW at 4 kΩ. The application experiment also proves the feasibility of the practical application of R-PEH, which provides a new solution for the research of hybrid energy harvesting systems.

A piezoelectric-electromagnetic hybrid energy harvester with frequency-up conversion mechanism towards low-frequency-low-intensity applications

This paper proposes a piezoelectric-electromagnetic hybrid energy harvester (PEHEH) with frequency-up conversion (FUC) mechanisms toward harvesting low-frequency-low-intensity, and wideband vibrational energy. The PEHEH consists of a stator with embedded coils, an eccentric rotor embedded with permanent magnets, and a fan-folded piezoelectric beam fixed to the stator. The eccentric rotor converts low-frequency straight vibration into rotational motion, and generates currents across the coils. The rotor could collide with the fan-folded beam, resulting in voltage generation due to the deformation of the fan-folded beam. The FUC mechanism broadens the bandwidth and harvests additional energy through the piezoelectric effect. The fan-folded beam can be considered as a nonlinear oscillator of hardening type. The electro-magnetic-mechanical system is modeled as a driven pendulum that impacts a mass-spring-damper system. The electromagnetic coupling effect is theoretically determined and equivalent to a nonlinear damping term. The nonlinear dynamical system is analyzed theoretically, numerically and experimentally. The results show that the bandwidth of the PEHEH is broadened than that of the energy harvester without the FUC mechanism. The maximum power reaches 26.4 mW at 4 Hz. The PEHEH can power an acceleration sensor at 4 Hz in laboratory environments and a temperature-humidity sensor in actual working conditions of an agricultural tractor's spray rod.

An Enhanced Nonlinear Energy Sink for Hybrid Bifurcation Passive Mitigation and Energy Harvesting From Aeroelastic Galloping Phenomena

Abstract Galloping is a self-excited vibration problem that structures immersed in fluid flow can experience. Due to its essential nonlinear phenomena, the structure exhibits limit cycle oscillations (LCOs), which, at high levels, can lead to failure of the systems. This work proposes an investigation of electromagnetic-enhanced nonlinear energy sinks (NES-EH) for the hybrid mitigation of aeroelastic LCOs and energy harvesting. The study focuses on a prismatic bluff body with a linear suspension immersed in the airflow, using classical steady nonlinear modeling for aerodynamic loads. The conventional NES approach is adopted, employing cubic stiffness and linear damping. Additionally, a linear electromagnetic transducer is included in the assembly for the energy harvesting process. By combining the method of multiple scales with the Harmonic Balance Method, analytical solutions are derived to characterize the system's dynamics under the influence of the device. The different response domains and their respective boundaries induced by the NES-EH are characterized based on the bifurcation diagrams. Furthermore, a slow invariant manifold (SIM) characterization is presented for each induced response domain, and its significant features are discussed. Parametric studies are carried out based on bifurcation analyses to assess the effect of NES-EH parameters on the galloping system dynamics, which allows for designing the absorber parameters. The electrical resistance is optimized to maximize the harvested power. The optimal design of NES-EH is then compared with classical energy harvesting solutions for the galloping problem. Additionally, a thorough analysis of the Target Energy Transfer phenomenon is performed.

Hybrid energy harvesting by reverse di-electric on a piezo-electric generator with thermo-couple and monitoring in WSN

Smart renewable energy harvesting has been implemented from hybrid sources such as solar and wind. The wireless sensor node is created for monitoring surface water. In the intelligent building, electrical energy is harvested from the hybrid source of solar and wind energy. The source energy was selected for the harvesting process by using a fuzzy controller. In this proposed method, piezo-electric reverse electro-wetting on di-electric energy harvesting is proposed where constant DC voltage is generated by a rectifier. A DC-DC converter is designed to power up the remote read-out sensor. The produced charge is transformed by a charge amplifier with the proportion of output voltage that is delivered to the wireless receiver. The harvested DC voltage varies with the temperature and external environmental effect. In our work, we obtained 6 × 10−3 W/m2 of voltage and this harvested energy is monitored using the Internet of Things (IoT) by the proposed EHOR (Energy Harvested Optimized Routing) algorithm.

Wearable All-Fabric Hybrid Energy Harvester to Simultaneously Harvest Radiofrequency and Triboelectric Energy.

Distributed micro-energy harvesting devices offer the flexibility, sustainability, and multi-scenario applicability that will be critical to wearable electronic products in the Internet of Things. The radiofrequency and triboelectric (RF-TE) hybrid energy harvester (HEH) concept and prototype is presented for the first time, to simultaneously capture the energy from ambient electromagnetic waves and biological motions. The proposed hybrid energy harvesting system consists of a wearable rectenna, a triboelectric nanogenerator (TENG), and a power management circuit (PMC). Among them, the all-fabric rectenna exhibits good impedance matching characteristics in the ISM frequency. The flexible TENG unit can generate a maximum power density of 0.024µWcm-2. The designed multifunctional fabric-based PMC can considerably enhance the controllability of harvested hybrid energy. Additionally, a normalizable fabric circuit board quasi surface mount technology (FCB-SMT) is proposed to integrate all modules on the same fabric substrate in one step, making the entire system superior mechanical robustness. The proposed wearable fabric-based RF-TE hybrid energy harvester is capable of successfully driving consumer electronics (such as sensors, watches, etc.). It provides a new energy solution strategy for self-powered wearable electronic devices and is anticipated to encourage the efficient utilization of renewable energy.