Micro-Fabricated Electromagnetic Power Generator to Scavenge Low Ambient Vibration

In this paper, micro-fabricated electromagnetic power generator is presented to convert the low level ambient vibration into electric energy. The proposed micro-power generator is comprised of three micro-components such as bulk-micromachined silicon spiral spring, low loss copper micro-coil, and NdFeB magnet to be assembled with low cost PDMS packaging substrate. In order to maximize the output power, magnet is applied as inertial mass at the center of silicon spiral spring to adjust its resonant frequency. Especially, NdFeB discrete/miniaturized magnet and copper wire wounded micro-coil were utilized to avoid the performance deterioration of the proposed device due to its miniaturization. It was specially designed for scavenging low ambient vibration of several tens of hertz and low acceleration under 1g. The fabricated device generated output power of 115.1 mu W and load voltage of 68.2 mV to the load resistance of 18.1 Omega from the vibration of 54Hz with acceleration of 0.57 g. The normalized power density was 590.4 mu W/cm(3).g(2).