Fabrication and performance optimization of an AA size electromagnetic energy harvester using magnetic spring

This paper presents an improved design of an AA size electromagnetic energy harvester based on vibration. It utilizes magnetic spring technique to scavenge energy from low frequency external vibration. The optimization of generator is done in two stages. First, ANSYS simulation is used to reduce the nonlinear behavior of flux density and to maximize the output voltage of generator by optimizing size of moving and fixed magnets. Second, the coil width, coil position and load resistance are optimized experimentally to maximize output power. The optimized energy harvester can generate 1.18 mW power at a load resistance of 97 Ω with 9 Hz resonance frequency and 0.5 mm of displacement.