[{"date_created":"2019-05-13T13:51:59Z","department":[{"_id":"151"}],"type":"journal_article","keyword":["Energy harvesting","Cantilever array","Bandwidth","Power increase"],"citation":{"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>.","short":"W. Al-Ashtari, M. Hunstig, T. Hemsel, W. Sextro, Sensors and Actuators A: Physical 200 (2013) 138–146.","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.","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} }","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>","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>."},"publication":"Sensors and Actuators A: Physical","abstract":[{"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.","lang":"eng"}],"_id":"9795","language":[{"iso":"eng"}],"page":"138 - 146","volume":200,"doi":"10.1016/j.sna.2013.01.008","user_id":"55222","author":[{"last_name":"Al-Ashtari","first_name":"Waleed","full_name":"Al-Ashtari, Waleed"},{"full_name":"Hunstig, Matthias","last_name":"Hunstig","first_name":"Matthias"},{"first_name":"Tobias","last_name":"Hemsel","full_name":"Hemsel, Tobias","id":"210"},{"first_name":"Walter","last_name":"Sextro","full_name":"Sextro, Walter","id":"21220"}],"title":"Enhanced energy harvesting using multiple piezoelectric elements: Theory and experiments","status":"public","year":"2013","intvolume":"       200","date_updated":"2022-01-06T07:04:20Z"},{"_id":"9796","language":[{"iso":"eng"}],"series_title":"Berichte aus dem IDS","page":"159-161","user_id":"55222","author":[{"first_name":"Waleed","last_name":"Al-Ashtari","full_name":"Al-Ashtari, Waleed"},{"full_name":"Hunstig, Matthias","last_name":"Hunstig","first_name":"Matthias"},{"id":"210","full_name":"Hemsel, Tobias","last_name":"Hemsel","first_name":"Tobias"},{"full_name":"Sextro, Walter","first_name":"Walter","last_name":"Sextro","id":"21220"}],"status":"public","year":"2013","title":"Characteristics of Piezoelectric Energy Harvesters in Autonomous Systems","date_updated":"2022-01-06T07:04:20Z","place":"Hannover, Germany","date_created":"2019-05-13T13:53:25Z","department":[{"_id":"151"}],"keyword":["Energy harvesting","harvester modeling","load dependence","generated voltage"],"type":"conference","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.","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} }","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.","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.","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.","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.","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."},"issue":"05/2013","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","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."}]},{"publication":"Ultrasonics Symposium (IUS), 2012 IEEE International","citation":{"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} }","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>","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.","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.","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>"},"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."}],"quality_controlled":"1","date_created":"2019-05-13T13:28:05Z","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"],"type":"conference","department":[{"_id":"151"}],"status":"public","title":"Piezoelectric applications of hydrothermal lead-free (K0.48Na0.52)NbO3 ceramics","year":"2012","author":[{"full_name":"Maeda, Takafumi","last_name":"Maeda","first_name":"Takafumi"},{"last_name":"Bornmann","first_name":"Peter","full_name":"Bornmann, Peter"},{"id":"210","first_name":"Tobias","last_name":"Hemsel","full_name":"Hemsel, Tobias"},{"last_name":"Morita","first_name":"Takeshi","full_name":"Morita, Takeshi"}],"publication_identifier":{"issn":["1948-5719"]},"date_updated":"2022-01-06T07:04:20Z","page":"194-195","language":[{"iso":"eng"}],"_id":"9788","doi":"10.1109/ULTSYM.2012.0048","user_id":"55222"}]