An Electromagnetic Micro Power Generator for Low-Frequency Environmental Vibrations Based on the Frequency Upconversion Technique

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper presents a microelectromechanical-system-based electromagnetic vibration-to-electrical power generator that can harvest energy from low-frequency external vibrations. The efficiency of vibration-based harvesters is proportional to excitation frequency, so the proposed generator is designed to convert low-frequency environmental vibrations to a higher frequency by employing the frequency upconversion (FupC) technique. It has been shown that the generator can effectively harvest energy from environmental vibrations of 70–150 Hz and generates 0.57-mV voltage with 0.25-nW power from a single cantilever by upconverting the input vibration frequency of 95 Hz–2 kHz. The fabricated generator size is <formula formulatype="inline"><tex Notation="TeX">$8.5\! \times\! 7\! \times \! 2.5 \ \hbox{mm}^{3}$</tex></formula>, and a total of 20 serially connected cantilevers have been used to multiply the generated voltage and power. The generator demonstrated in this paper is designed for the proof of concept, and the power and voltage levels can further be increased by increasing the number of cantilevers or coil turns. The performance of the generator is also compared with that of a same-sized <emphasis emphasistype="boldital"> custom-made</emphasis> traditional magnet–coil-type generator and with that of a traditional generator from the literature to prove its effectiveness.<formula formulatype="inline"><tex Notation="TeX">$\hfill$</tex></formula>[2009-0136] </para>