Energy Transduction by Magnetoelectric Coupling Effect
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The deployment of wireless sensor networks (WSNs) for the internet of things (IoT) and remote monitoring devices has made tremendous progress in the last few years. At the same time, energy harvesters are also being developed to satisfy the power requirement of WSNs and other low power consumption electronics, to increase the device operating time and overcome the limitations of conventional electric power supplies, including batteries. Among various resources for energy transduction devices such as energy harvesters, the stray magnetic noise produced by power transmission infrastructures and associated mechanical vibrations are ubiquitous energy sources that could be converted into electricity by high efficiency energy conversion materials or devices. Electro-magnetic energy transduction systems that operate on the principle of Faraday's induction law can provide sufficient power from strong magnetic fields. However, under weak magnetic fields with low frequency such as 50/60 Hz, the power generated from an electromagnetic device is disappointingly small. Alternative energy transduction technologies with high power density and small device volume/dimensions are obviously necessary for WSNs of IoT. In this presentation, the current status and prospects of an emerging magnetic energy transduction technology, the so-called magneto-mechano-electric (MME) generators, are reviewed. MME generators utilize the magnetoelectric (ME) coupling in composites of piezoelectric and magnetostrictive materials and interaction between the proof magnet mass and magnetic field. Since the piezoelectric phase in the composite also responds to mechanical vibration directly, an ME-based energy harvester can harness energy from both mechanical vibrations and magnetic fields simultaneously. This combination is expected to enhance the total power output and conversion efficiency. The MME generator can be a ubiquitous power source for WSNs, low power electronic devices, and wireless charging systems by transducing energy from the tiny magnetic fields present as parasitic magnetic noise in an ambient environment.