Design and optimization of a linear vibration-driven electromagnetic micro-power generator

We present design and optimization of a linear electromagnetic generator suitable to supply power to body-worn sensor nodes. The design is based on an air-cored tubular architecture and a flexible translator bearing. A two-stage procedure is used to optimize the generator. First, the geometric parameters of stator and translator are optimized for maximum electromagnetic force capability based on magnetostatic finite element simulations. Second, mechanical resonance frequency and load resistance are optimized regarding maximum output power using lumped-parameter simulations and measured acceleration data from human walking motion. When worn on the body during walking, the optimized generator has an output power of 2-25 μ W, depending on its position on the human body. Stator and translator occupy a volume of 0.25 cm3. We have built a working generator prototype and validated the simulations.