A recent paper in European Physical Journal Special Topics demonstrates how energy can be harvested from vibrating micromagnets in the most effective way to power wireless sensors.
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The Internet of Things, or the wireless interconnection of everyday objects, is based on wireless sensor networks, which require a low but consistent supply of electrical energy. Electromagnetic energy harvesters, which produce energy straightforwardly from the environment, can provide this.
Lise-Marie Lacroix of the Université de Toulouse in France worked with colleagues from Toulouse, Grenoble, and Atlanta, Georgia, to improve the design of one such energy harvester so that it produces electricity as effectively as possible. The European Physical Journal Special Topics has now published this article.
The Internet of Things is made up of a huge number of small, portable devices, each of which requires its own micro-energy source. Batteries are unsuitable for this because they must be replaced or recharged frequently. Instead, a variety of technologies are being taken into account, with electromagnetic energy harvesting being one of the most compelling.
A vibrating plate holds an array of micromagnets facing and coupled with a parallel, static coil in an electromagnetic energy harvester. The vibrating magnets produce electrical energy, and the amount of electricity that can gain entry into a circuit is determined by the design of the coil and magnet, as well as the spacing between them.
Lacroix and her colleagues looked at a system with state-of-the-art NdFeB magnets, which are made of an alloy of the rare earth metal neodymium with iron and boron. They discovered that power could be optimized by balancing the number of turns in the coil with the spacing of the magnets in the array; lowering the distance between the coil and the array and increasing the thickness of the magnets can also help.
We are now producing harvesters using the guidelines that we have developed through this study.
Lise-Marie Lacroix, Université de Toulouse
These devices are generally useful in industries such as aerospace, automotive and biomedicine, as well as others that rely on the Internet of Things.
Journal Reference:
Lecerf, I., et al. (2022) Optimization of a vibrating MEMS electromagnetic energy harvester using simulations. European Physical Journal Special Topics. doi.org/10.1140/epjs/s11734-022-00577-8.