---
_id: '9795'
abstract:
- lang: eng
  text: Power and bandwidth of piezoelectric harvesters can be increased by using
    multiple piezoelectric elements in one harvester. In this contribution, a novel
    energy harvesting cantilever array with magnetic tuning including three piezoelectric
    bimorphs is investigated theoretically and experimentally, with a good agreement
    between model and experiment. Other than harvester designs proposed before, this
    array is easy to manufacture and insensitive to manufacturing tolerances because
    its optimum operation frequency can be re-adjusted after fabrication. Using the
    superposition principle, the Butterworth-Van Dyke model and a mechanical lumped
    parameters model, the generated voltage and current are determined analytically.
    Formulas for calculating the power generated by array harvesters with an arbitrary
    number of piezoelectric elements connected in series or in parallel are derived.
    It is shown that optimum harvester design must take both the connected load and
    the operating frequency into account. Strategies for connecting multiple bimorphs
    to increase the maximum generated power and/or enhance the bandwidth compared
    to a single bimorph harvester are investigated. For bandwidth enhancement it is
    essential that individual rectifiers are used for the bimorphs. An example with
    three bimorphs shows that, depending on the chosen tuning strategy, the power
    is increased by about 340\% or the bandwidth is increased by about 500\%, compared
    to one single bimorph.
author:
- first_name: Waleed
  full_name: Al-Ashtari, Waleed
  last_name: Al-Ashtari
- first_name: Matthias
  full_name: Hunstig, Matthias
  last_name: Hunstig
- first_name: Tobias
  full_name: Hemsel, Tobias
  id: '210'
  last_name: Hemsel
- first_name: Walter
  full_name: Sextro, Walter
  id: '21220'
  last_name: Sextro
citation:
  ama: 'Al-Ashtari W, Hunstig M, Hemsel T, Sextro W. Enhanced energy harvesting using
    multiple piezoelectric elements: Theory and experiments. <i>Sensors and Actuators
    A: Physical</i>. 2013;200:138-146. doi:<a href="https://doi.org/10.1016/j.sna.2013.01.008">10.1016/j.sna.2013.01.008</a>'
  apa: 'Al-Ashtari, W., Hunstig, M., Hemsel, T., &#38; Sextro, W. (2013). Enhanced
    energy harvesting using multiple piezoelectric elements: Theory and experiments.
    <i>Sensors and Actuators A: Physical</i>, <i>200</i>, 138–146. <a href="https://doi.org/10.1016/j.sna.2013.01.008">https://doi.org/10.1016/j.sna.2013.01.008</a>'
  bibtex: '@article{Al-Ashtari_Hunstig_Hemsel_Sextro_2013, title={Enhanced energy
    harvesting using multiple piezoelectric elements: Theory and experiments}, volume={200},
    DOI={<a href="https://doi.org/10.1016/j.sna.2013.01.008">10.1016/j.sna.2013.01.008</a>},
    journal={Sensors and Actuators A: Physical}, author={Al-Ashtari, Waleed and Hunstig,
    Matthias and Hemsel, Tobias and Sextro, Walter}, year={2013}, pages={138–146}
    }'
  chicago: 'Al-Ashtari, Waleed, Matthias Hunstig, Tobias Hemsel, and Walter Sextro.
    “Enhanced Energy Harvesting Using Multiple Piezoelectric Elements: Theory and
    Experiments.” <i>Sensors and Actuators A: Physical</i> 200 (2013): 138–46. <a
    href="https://doi.org/10.1016/j.sna.2013.01.008">https://doi.org/10.1016/j.sna.2013.01.008</a>.'
  ieee: 'W. Al-Ashtari, M. Hunstig, T. Hemsel, and W. Sextro, “Enhanced energy harvesting
    using multiple piezoelectric elements: Theory and experiments,” <i>Sensors and
    Actuators A: Physical</i>, vol. 200, pp. 138–146, 2013.'
  mla: 'Al-Ashtari, Waleed, et al. “Enhanced Energy Harvesting Using Multiple Piezoelectric
    Elements: Theory and Experiments.” <i>Sensors and Actuators A: Physical</i>, vol.
    200, 2013, pp. 138–46, doi:<a href="https://doi.org/10.1016/j.sna.2013.01.008">10.1016/j.sna.2013.01.008</a>.'
  short: 'W. Al-Ashtari, M. Hunstig, T. Hemsel, W. Sextro, Sensors and Actuators A:
    Physical 200 (2013) 138–146.'
date_created: 2019-05-13T13:51:59Z
date_updated: 2022-01-06T07:04:20Z
department:
- _id: '151'
doi: 10.1016/j.sna.2013.01.008
intvolume: '       200'
keyword:
- Energy harvesting
- Cantilever array
- Bandwidth
- Power increase
language:
- iso: eng
page: 138 - 146
publication: 'Sensors and Actuators A: Physical'
status: public
title: 'Enhanced energy harvesting using multiple piezoelectric elements: Theory and
  experiments'
type: journal_article
user_id: '55222'
volume: 200
year: '2013'
...
---
_id: '9796'
abstract:
- lang: eng
  text: 'A basic autonomous system powered by a piezoelectric harvester contains three
    components apart from the harvester: a fullwave rectifier, a reservoir capacitor
    and an electronic device performing the primary task of the system. In this contribution,
    a model describing the operation of such a system is derived. It is found that
    in steady-state operation, the piezoelectric harvester experiences two alternating
    load conditions due to the rectification process. These alternating load conditions
    can have a significant effect on the operation of the harvester and must be considered
    in the design of autonomous systems. The results also show that such an autonomous
    system works efficiently if it is connected to a high impedance load and excited
    by a frequency matching the anti-resonance frequency of the piezoelectric harvester.'
author:
- first_name: Waleed
  full_name: Al-Ashtari, Waleed
  last_name: Al-Ashtari
- first_name: Matthias
  full_name: Hunstig, Matthias
  last_name: Hunstig
- first_name: Tobias
  full_name: Hemsel, Tobias
  id: '210'
  last_name: Hemsel
- first_name: Walter
  full_name: Sextro, Walter
  id: '21220'
  last_name: Sextro
citation:
  ama: 'Al-Ashtari W, Hunstig M, Hemsel T, Sextro W. Characteristics of Piezoelectric
    Energy Harvesters in Autonomous Systems. In: <i>Proceedings of 10th International
    Workshop on Piezoelectric Materials and Applications and 8th Energy Harvesting
    Workshop, Hannover, Germany, 14.-17.7.2013</i>. Berichte aus dem IDS. Hannover,
    Germany; 2013:159-161.'
  apa: Al-Ashtari, W., Hunstig, M., Hemsel, T., &#38; Sextro, W. (2013). Characteristics
    of Piezoelectric Energy Harvesters in Autonomous Systems. In <i>Proceedings of
    10th International Workshop on Piezoelectric Materials and Applications and 8th
    Energy Harvesting Workshop, Hannover, Germany, 14.-17.7.2013</i> (pp. 159–161).
    Hannover, Germany.
  bibtex: '@inproceedings{Al-Ashtari_Hunstig_Hemsel_Sextro_2013, place={Hannover,
    Germany}, series={Berichte aus dem IDS}, title={Characteristics of Piezoelectric
    Energy Harvesters in Autonomous Systems}, number={05/2013}, booktitle={Proceedings
    of 10th International Workshop on Piezoelectric Materials and Applications and
    8th Energy Harvesting Workshop, Hannover, Germany, 14.-17.7.2013}, author={Al-Ashtari,
    Waleed and Hunstig, Matthias and Hemsel, Tobias and Sextro, Walter}, year={2013},
    pages={159–161}, collection={Berichte aus dem IDS} }'
  chicago: Al-Ashtari, Waleed, Matthias Hunstig, Tobias Hemsel, and Walter Sextro.
    “Characteristics of Piezoelectric Energy Harvesters in Autonomous Systems.” In
    <i>Proceedings of 10th International Workshop on Piezoelectric Materials and Applications
    and 8th Energy Harvesting Workshop, Hannover, Germany, 14.-17.7.2013</i>, 159–61.
    Berichte Aus Dem IDS. Hannover, Germany, 2013.
  ieee: W. Al-Ashtari, M. Hunstig, T. Hemsel, and W. Sextro, “Characteristics of Piezoelectric
    Energy Harvesters in Autonomous Systems,” in <i>Proceedings of 10th International
    Workshop on Piezoelectric Materials and Applications and 8th Energy Harvesting
    Workshop, Hannover, Germany, 14.-17.7.2013</i>, 2013, no. 05/2013, pp. 159–161.
  mla: Al-Ashtari, Waleed, et al. “Characteristics of Piezoelectric Energy Harvesters
    in Autonomous Systems.” <i>Proceedings of 10th International Workshop on Piezoelectric
    Materials and Applications and 8th Energy Harvesting Workshop, Hannover, Germany,
    14.-17.7.2013</i>, no. 05/2013, 2013, pp. 159–61.
  short: 'W. Al-Ashtari, M. Hunstig, T. Hemsel, W. Sextro, in: Proceedings of 10th
    International Workshop on Piezoelectric Materials and Applications and 8th Energy
    Harvesting Workshop, Hannover, Germany, 14.-17.7.2013, Hannover, Germany, 2013,
    pp. 159–161.'
date_created: 2019-05-13T13:53:25Z
date_updated: 2022-01-06T07:04:20Z
department:
- _id: '151'
issue: 05/2013
keyword:
- Energy harvesting
- harvester modeling
- load dependence
- generated voltage
language:
- iso: eng
page: 159-161
place: Hannover, Germany
publication: Proceedings of 10th International Workshop on Piezoelectric Materials
  and Applications and 8th Energy Harvesting Workshop, Hannover, Germany, 14.-17.7.2013
quality_controlled: '1'
series_title: Berichte aus dem IDS
status: public
title: Characteristics of Piezoelectric Energy Harvesters in Autonomous Systems
type: conference
user_id: '55222'
year: '2013'
...
---
_id: '9788'
abstract:
- lang: eng
  text: 'A hydrothermal method utilizes a crystallization process in the solution
    so that the pure and high-quality powders can be realized. Sintering from the
    hydrothermal KNbO3 and NaNbO3 powders, a high-dense lead-free piezoelectric (K,Na)NbO3
    ceramics could be obtained (density: 98.8\%). Concerning about the g33 constant,
    high value as large as commercial PZT ceramics was measured. Therefore, the hydrothermal
    (K,Na)NbO3 ceramics is usable for the sensors and the energy harvesting devices.
    To demonstrate the (K,Na)NbO3 ceramics, a hydrophone sensor was fabricated and
    evaluated.'
author:
- first_name: Takafumi
  full_name: Maeda, Takafumi
  last_name: Maeda
- first_name: Peter
  full_name: Bornmann, Peter
  last_name: Bornmann
- first_name: Tobias
  full_name: Hemsel, Tobias
  id: '210'
  last_name: Hemsel
- first_name: Takeshi
  full_name: Morita, Takeshi
  last_name: Morita
citation:
  ama: 'Maeda T, Bornmann P, Hemsel T, Morita T. Piezoelectric applications of hydrothermal
    lead-free (K0.48Na0.52)NbO3 ceramics. In: <i>Ultrasonics Symposium (IUS), 2012
    IEEE International</i>. ; 2012:194-195. doi:<a href="https://doi.org/10.1109/ULTSYM.2012.0048">10.1109/ULTSYM.2012.0048</a>'
  apa: Maeda, T., Bornmann, P., Hemsel, T., &#38; Morita, T. (2012). Piezoelectric
    applications of hydrothermal lead-free (K0.48Na0.52)NbO3 ceramics. In <i>Ultrasonics
    Symposium (IUS), 2012 IEEE International</i> (pp. 194–195). <a href="https://doi.org/10.1109/ULTSYM.2012.0048">https://doi.org/10.1109/ULTSYM.2012.0048</a>
  bibtex: '@inproceedings{Maeda_Bornmann_Hemsel_Morita_2012, title={Piezoelectric
    applications of hydrothermal lead-free (K0.48Na0.52)NbO3 ceramics}, DOI={<a href="https://doi.org/10.1109/ULTSYM.2012.0048">10.1109/ULTSYM.2012.0048</a>},
    booktitle={Ultrasonics Symposium (IUS), 2012 IEEE International}, author={Maeda,
    Takafumi and Bornmann, Peter and Hemsel, Tobias and Morita, Takeshi}, year={2012},
    pages={194–195} }'
  chicago: Maeda, Takafumi, Peter Bornmann, Tobias Hemsel, and Takeshi Morita. “Piezoelectric
    Applications of Hydrothermal Lead-Free (K0.48Na0.52)NbO3 Ceramics.” In <i>Ultrasonics
    Symposium (IUS), 2012 IEEE International</i>, 194–95, 2012. <a href="https://doi.org/10.1109/ULTSYM.2012.0048">https://doi.org/10.1109/ULTSYM.2012.0048</a>.
  ieee: T. Maeda, P. Bornmann, T. Hemsel, and T. Morita, “Piezoelectric applications
    of hydrothermal lead-free (K0.48Na0.52)NbO3 ceramics,” in <i>Ultrasonics Symposium
    (IUS), 2012 IEEE International</i>, 2012, pp. 194–195.
  mla: Maeda, Takafumi, et al. “Piezoelectric Applications of Hydrothermal Lead-Free
    (K0.48Na0.52)NbO3 Ceramics.” <i>Ultrasonics Symposium (IUS), 2012 IEEE International</i>,
    2012, pp. 194–95, doi:<a href="https://doi.org/10.1109/ULTSYM.2012.0048">10.1109/ULTSYM.2012.0048</a>.
  short: 'T. Maeda, P. Bornmann, T. Hemsel, T. Morita, in: Ultrasonics Symposium (IUS),
    2012 IEEE International, 2012, pp. 194–195.'
date_created: 2019-05-13T13:28:05Z
date_updated: 2022-01-06T07:04:20Z
department:
- _id: '151'
doi: 10.1109/ULTSYM.2012.0048
keyword:
- crystallisation
- hydrophones
- piezoceramics
- potassium compounds
- powder technology
- powders
- sensors
- sintering
- sodium compounds
- (K0.48Na0.52)NbO3
- KNbO3 powder
- NaNbO3 powder
- crystallization
- energy harvesting devices
- g33 constant
- hydrophone sensor
- hydrothermal lead-free (K0.48Na0.52)NbO3 ceramics
- hydrothermal method
- piezoelectric applications
- sintering
- Materials
- Transducers
language:
- iso: eng
page: 194-195
publication: Ultrasonics Symposium (IUS), 2012 IEEE International
publication_identifier:
  issn:
  - 1948-5719
quality_controlled: '1'
status: public
title: Piezoelectric applications of hydrothermal lead-free (K0.48Na0.52)NbO3 ceramics
type: conference
user_id: '55222'
year: '2012'
...