A 3-D magnetic equivalent circuit of an axial-flux MEMS micromotor

This paper presents a novel axial-flux microelectromechanical systems (MEMS) based micromotor with dual-rotor and 10mm diameter. The characteristics of MEMS micromotor are analyzed and modeled using a 3-D magnetic equivalent circuit (MEC) taking the leakage fluxes and fringing effect into account. Such methodology yields more accurate prediction of the flux distribution inside the machine, back electromotive force (EMF) waveform and the torque. The key point of the analytical model is to compute the magnetic flux density in the air gap generated by the permanent magnet. An accurate prediction method of the leakage fluxes based on an improved pigeon-inspired optimization (PIO) algorithm is proposed in this paper. The feasibility of the proposed method is validated by the 3-D finite element analysis (FEA). Finally, the method is applied to design and manufacture the micromotor.