Lise-Marie Lacroix from the Université de Toulouse, France, with colleagues from Toulouse, Grenoble and Atlanta, Georgia, U.S.A have used a mathematical technique, finite element simulation, to optimize the design of an electromagnetic energy harvester so that it generates electricity as efficiently as possible.

The scientists integrated the math into computer modeling to optimize the design of the electromagnetic energy harvester to power wireless sensor networks for the Internet of Things.

The vibrating plate is connected to the frame by 4 folded beams (each containing 3 folds). The magnetic array is on the 6×4 mm2 vibrating plate and centered with respect to the turns on one side of the facing planar coil. Image Credit: Université de Toulouse. Click image for the largest view.

The wireless interconnection of everyday objects known as the Internet of Things depends on wireless sensor networks that need a low but constant supply of electrical energy. This can be provided by electromagnetic energy harvesters that generate electricity directly from the environment.

This team’s work paper has been published in the journal European Physical Journal Special Topics.

The Internet of Things consists of an enormous number of generally small, portable devices, each of which needs its own sustainable micro-energy source. Batteries are unsatisfactory for this as they will often need to be replaced or recharged. Many different technologies are being considered instead, with one of the most promising solutions being electromagnetic energy harvesting.

An electromagnetic energy harvester consists of a vibrating plate holding an array of micromagnets facing and coupled with a parallel, static coil. Electrical energy is generated by the vibrating magnets and the amount of electricity that can enter a circuit depends on the design of the coil and magnet and the spacing between them.

Lacroix and her team studied a system in which the magnets were state-of-the-art NdFeB ones – that is, they were composed from an alloy of the rare earth metal neodymium with iron and boron.

They found that power could be optimized through a trade-off between the spacing of the magnets in the array and the number of turns in the coil; reducing the distance between coil and array and increasing the thickness of the magnets can also increase it.

“We are now producing harvesters using the guidelines that we have developed through this study,” she explained. These devices are likely to prove useful in the aerospace, automotive and biomedical sectors and others that have come to rely on the Internet of Things.


Here is more microelectronics development. It’s welcome and likely going to improve everyone’s standard of living. The improvement might be noticeable, or maybe not so much. In any case substituting an energy harvester sounds like a great idea, as skipping battery change outs would save on time and materials along with, probably, more reliability.

Everyone keep in mind that these devices are not making much power, just enough to run small devices and perhaps some transmission energy for signals. But the list of ideas where sensing and control optimization is still young. One can expect that the list is going to expand enormously as more ideas get integrated and power output grows.


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