A methodology for low-speed broadband rotational energy harvesting using piezoelectric transduction and frequency up-conversion

Zuo

Yang

et al. 2020

Sensors

To reveal the nonlinear mechanism of the tri-stable piezoelectric vibration energy harvester based on composite shape beam (TPEH-C) and its influence on the system response, the nonlinear restoring force and the nonlinear magnetic force are discussed and analyzed in this paper. The nonlinear magnetic model is acquired by using equivalent magnetizing current theory, and the nonlinear resilience model is obtained by fitting experimental data. The corresponding distributed parameter model based on generalized Hamiltonian variation principle has been established. Frequency response functions for the TPEH-C are derived according to harmonic balance expansion, and the influence of different magnet distances and different excitation accelerations on the response amplitude and bandwidth of the TPEH-C are investigated. More importantly, the correctness of the theoretical analysis is verified by experiments. The results reveal that the spectrum of composite beam shows hard characteristic and the depth of potential well is changed, which provides a new way to ameliorate the potential well of the TPEH-C. A suitable magnet distance enables the TPEH-C to improve the response amplitude and the effective frequency range. The results in this paper have a theoretical guiding significance for the optimal design and engineering application of the TPEH-C.

Section: Introductionmentioning

confidence: 99%

A Tri-Stable Piezoelectric Vibration Energy Harvester for Composite Shape Beam: Nonlinear Modeling and Analysis

Zuo

Yang

et al. 2020

Sensors

“…Zhou et al developed a bistable energy harvester made of a piezoelectric coupled cantilever with a proof magnet, two curved wings, and two fixed magnets, which can efficiently harvest wind energy in a wide range of wind speeds. Fu and Yeatman designed a piezoelectric harvester excited by the magnetic repulsion between the magnet atop the cantilever and the magnet fixed on a rotating magnet on a revolving circular plate, which is effective for low‐speed rotational energy harvesting by using its frequency upconversion design. Li et al proposed a generalized multimode harvester of a piezoelectric coupled cantilever attached with many small cantilevers with tip masses.…”

Section: Introductionmentioning

confidence: 99%

A study on a near‐shore cantilevered sea wave energy harvester with a variable cross section

Energy Science & Engineering

Xie

Song

et al. 2019

A cantilevered piezoelectric coupled energy harvester with variable cross section is proposed to obtain the electric power from the longitudinal motion of the near‐shore sea wave. In order to describe the practical process of the sea wave energy harvesting, a mathematical model of the harvester is established based on Airy linear wave theory and Bessel equations to calculate the output charge, voltage, current, and power. Compared to traditional cantilever harvesters with uniform cross section, this harvesting device has a larger energy harvesting efficiency for its more uniform and bigger surface strain in the action of the sea wave. The computation results show a root mean square (RMS) of electric power of 132.6 W can be reached up with the cantilever height, the wave height, and the wavelength of 2.5, 2, and 12.5 m, respectively, which is 2.41 times of those of the traditional cantilever harvester with uniform cross section. In addition, the output powers of the harvester in tiding and in array are also discussed. This research provided a new practical and efficient method of harvesting near‐shore sea wave energy to supply the electric power demand of the households near seaside.

“…3,4 Frequency-up conversion is adopted for amplification of the response of harvesters from low frequency ambient sources to the naturally higher operating frequencies of mechanical vibration harvesters. [5][6][7] Many researchers have recently concentrated on nonlinear systems as a means of extending the coupling between the excitation and a harmonic oscillator to a wider bandwidth compared to the naturally narrower bandwidth of linear resonators. [8][9][10][11][12] The off-resonance approaches implemented in the design of such systems can introduce a nonlinear restoring force based on the use of magnetic or mechanical forces, without the need for natural frequency self-tuning.…”

Section: 2mentioning

confidence: 99%

Stabilising high energy orbit oscillations by the utilisation of centrifugal effects for rotating-tyre-induced energy harvesting

Applied Physics Letters

Zheng

Nakano

et al. 2018

Nonlinear energy harvesters are frequently considered in preference to linear devices because they can potentially overcome the narrow frequency bandwidth limitations inherent to linear variants; however, the possibility of variable harvesting efficiency is raised for the nonlinear case. This paper proposes a rotational energy harvester which may be fitted into an automobile tyre, with the advantage that it may broaden the rotating frequency bandwidth and simultaneously stabilise highenergy orbit oscillations. By consideration of the centrifugal effects due to rotation the overall restoring force will potentially be increased for a cantilever implemented within the harvester, and this manifests as an increase in its equivalent elastic stiffness. In addition this study reveals that the initial potential well barriers become as shallow as those for a bistable system. When the rotational frequency increases beyond an identifiable boundary frequency the system transforms into one with a potential barrier of a typical monostable system. On this basis the inter-well motion of the bistable system can provide sufficient kinetic energy so that the cantilever maintains its high-energy orbit oscillation for monostable hardening behaviour.Furthermore, in a vehicle drive experiment it has been shown that the effective rotating frequency bandwidth can be widened from 15 km/h -25 km/h to 10 km/h -40 km/h. In addition it is confirmed that the centrifugal effects can improve the harvester performance, producing a mean power of 61 W at a driving speed of 40 km/h, and this is achieved by stabilising the high-energy orbit oscillations of the rotational harvester.Given the generally narrow bandwidth of operating frequency for traditional linear systems it is natural to want to explore technologies that may broaden the bandwidth in order to convert optimally the energy in as much of the surrounding vibrational excitations into a useful electrical form as possible. Various principles have been already explored including resonant frequency tuning, the use of multi-frequency converter arrays, frequency-up conversion, and specific nonlinear approaches. As linear energy harvesters can only usually deliver power when the excitation frequency closely _____________________________ a) Electronic