Magnetic induction micromachine - Part III: Eddy currents and nonlinear effects

The magnetic induction micromachine fabricated in Part II (see this issue or Ref. [2]) was not laminated, as designed in Part I (see this issue or Ref. [1]). Consequently, eddy currents in the stator core, and the associated nonlinear saturation, significantly decreased its performance from that predicted in Part I. To investigate and explain these phenomena and their consequences, this paper models the behavior of the solid-stator-core machine fabricated in Part II using a finite-difference time-domain numerical analysis. The inherent stiffness in the time-domain integration of Maxwell's equations is mitigated via reducing the speed of light artificially by five orders of magnitude, while taking special care that assumptions of magneto-quasi-static behavior are still met. The results from this model are in very good agreement with experimental data from the tethered magnetic induction micro motor.