Design, fabrication and test of integrated micro-scale vibration-based electromagnetic generator

Abstract

This paper discusses the design, fabrication and testing of electromagnetic microgenerators. Three different designs of power generators are partially micro-fabricated and assembled. Prototype A having a wire-wound copper coil, Prototype B, an electrodeposited copper coil both on a deep reactive ion etched (DRIE) silicon beam and paddle. Prototype C uses moving NdFeB magnets in between two micro-fabricated coils. The integrated coil, paddle and beam were fabricated using standard micro-electro-mechanical systems (MEMS) processing techniques. For Prototype A, the maximum measured power output was 148nW at 8.08kHz resonant frequency and 3.9m/s2 acceleration. For Prototype B, the microgenerator gave a maximum load power of 23nW for an acceleration of 9.8m/s2, at a resonant frequency of 9.83kHz. This is a substantial improvement in power generated over other micro-fabricated silicon-based generators reported in literature. This generator has a volume of 0.1cm3 which is lowest of all the silicon-based micro-fabricated electromagnetic power generators reported. To verify the potential of integrated coils in electromagnetic generators, Prototype C was assembled. This generated a maximum load power of 586nW across 110Ω load at 60Hz for an acceleration of 8.829m/s2.