Vibration Power Generation Property of U-Shaped Unimorph Device Using Grain-Oriented Electrical Steel.

The performance of vibration power generation using the inverse magnetostrictive effect increases with increasing its device size. In this study, grain-oriented electrical steel that can be largely produced was investigated as a core material, using a U-shaped unimorph device at a laboratory scale. The device using a grain-oriented electrical steel core (16mm long with a 1.4mm² cross-section) with the rolling direction (RD) along the stress direction exhibited the effective open-circuit voltage of 0.89V under an optimum bias magnetic field, when the free-end of the device was vibrated with a maximum amplitude of 2.0mm at a mechanical resonance frequency of 108 Hz. In addition, an average output power of 300µW was obtained by adjusting the load resistance. The above-mentioned properties of the RD unimorph core device were superior to those of the transverse direction (TD) unimorph core device, because the magnetic flux density change in the RD core was approximately 0.65 T, which was larger than that in the TD core. Therefore, grain-oriented electrical steel with the RD direction is a useful core material for developing large-sized devices with high performance. [ABSTRACT FROM AUTHOR]