A Novel Magnetic Energy Harvester Using Spinning Magnetoelectric Transducer

Abstract

Over recent years, there has been a growing interest in the held of energy harvesters and their applications across a wide range of areas. In the context of harvesting ambient stray magnetic energy, a magnetoelectric (ME) transducer based on piezoelectric transduction has attracted most scientihc attention. Though the ME transducers based on the electromagnetic (EM) induction mechanism promises are highly efhcient and much more easier to be integrated, research on this specihc type of ME transducer has been scarcely reported. This paper presents the design, fabrication, and experimental results of a novel EM energy harvester. Unlike other EM harvesters that linearly vibrate, the proposed one operates in a rotatory mode, making use of a specially designed magnet array to convert the horizontal ac magnetic held into a vertical spinning magnetic held, as well as the printing coils to scavenge energy from the rotatory magnetic held. In this paper, the influence of the load, the applied magnetic held, and the magnet's spatial arrangement are studied analytically, and the experimental results obtained by our fabricated prototype are consistent with the simulation results. The fabricated harvester prototype is able to generate 23.1 μW under a 2 Oe magnetic held at a resonant frequency of 10 Hz, corresponding to a power density of 14.2 μW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . Simulation and experimental results show that miniaturizing the harvester (i.e., reducing both the volume of magnet array and the area of printing coils) as well as increasing the coil turns can bring about a higher resonant frequency and a higher power density, which makes the micro-machined EM harvester a better ht for the ubiquitous 60 Hz ambient magnetic energy.