This paper presents a tunable electromagnetic vibration-based micro-generator with closed
loop frequency tuning. Frequency tuning is realized by applying an axial tensile force to the
micro-generator. A closed-loop frequency tuning system has been developed to control the
tuning process so that the generator always operates at the ambient vibration frequency to
make the entire process automatic. Experimentally the resonant frequency has been
successfully tuned from 67.6 to 98 Hz when various axial tensile forces were applied to the …