Scaling effects for electromagnetic vibrational power generators

This paper investigates how the power generated by electromagnetic based vibrational power generators scales with the dimension of the generator. The effects of scaling on the magnetic fields, the coil parameters and the electromagnetic damping are presented. An analysis is presented for both wire-wound coil technology and micro-fabricated coils. The power obtainable from electromagnetic generators in the dimension range of 1-10 mm is calculated. It is shown that the theoretical maximum power scales with the cube of the dimension. It is also shown that the high coil resistance associated with micro-coils severely restricts the power, which can be extracted.