LAUSR

This paper develops a 3-D analytical model to compute the no-load magnetic-field distribution in a flux reversal linear-rotary permanent-magnet actuator (FR-LRPMA) with two permanent-magnet (PM) poles (PM_pole) and two ferromagnetic poles (Fe_pole) on each stator tooth. Laplace’s and Poisson’s equations are built assuming that the stator and the rotor are slotless and both the permeances of Fe_pole and PM_pole are the same. The tubular mover is transferred into a planar one using a curvature factor. Then a 2-D model and 3-D model for calculating the air-gap relative permeances are proposed considering the effect of slot and the permeance difference of Fe_pole and PM_pole, respectively. The expressions of 3-D magnetic flux density, cogging force, and cogging torque of the FR-LRPMA are subsequently derived and verified using the finite-element method.