Electromagnetic Vibrational Energy Harvester With Microfabricated Springs and Flexible Coils

In this article, an electromagnetic vibrational energy harvester (EVEH) device has been designed and fabricated based on the hybrid microelectromechanical system and flexible circuit technology. The designed EVEH is composed of a disc magnet suspended by four microfabricated silicon springs above a stack of high-density flexible planar coils. At a sinusoidal acceleration with a peak-to-peak amplitude of 1 g, an output peak-to-peak voltage of 208.3 mV, and an output power of 10.5 mu W are measured at the resonant frequency of 143 Hz. At an elevated acceleration of 7 g, a maximum output peak-to-peak voltage of 333.1 mV is realized with an increased magnet-coil distance of 0.65 mm.