Magnetic and electric sizing of a miniature planar spiral transformer

This paper presents mathematical models and numerical simulation results for a notional miniature, planar, spiral transformer (MPST) fabricated in MEMS technology, for galvanic separation, proposed to equip an electric harvesting device (EHD). Two types of core - ferrite and (partially) magnetic nanofluid - are considered, and the lumped parameters (inductances and capacitances) of the MPST are computed. We found that magnetization body forces that occur in the super-paramagnetic nanofluid core result in complex, steady state flows consisting of fully 3D recirculation cells. The lumped parameters of the MPST were computed using 2D and 3D models and the results are in satisfactory good agreement.