Design and Fabrication of Electromagnetic Induction Type MEMS Generators with Ceramic Magnetic Circuit

In this paper, miniature electromagnetic induction type MEMS generators are developed and demonstrate a power generation. The fabricated MEMS generators use a miniature ball-bearing for stable rotational motion for an air turbine. Moreover, the MEMS turbine is combined with the multilayer ceramic magnetic circuit because it realizes the miniature three-dimensional coil structure with the magnetic core. Two type magnetic circuits; a single-phase type and a three-phase type are designed. The maximum output power of the single-phase type generator was 2.41 mVA when the rotational speed was 290,135 rpm and the load resistance of 8ohm was connected. The maximum output power of the three-phase type generator was 3.01 mVA when the rotational speed was 228,484 rpm and the load resistance of 3 ohm was connected. To achieve more high output power, optimization of the magnetic flux introducing part shape is required to suppress the magnetic flux leakage. For the three-phase type generator, alignment error and difference of the coil inductance influence the output value.