An analytical model of axial magnetic thrust and Finite Element simulation for a moving magnet linear motor

An analytical model of equivalent magnet circuits was established for a moving magnet linear oscillatory motor. The expressions of axial magnetic thrust acting on the mover were derived and the characteristic relations of magnetic thrust were analyzed with mover position and excitating electric current. At the same time, an analytical model of the magnet thrust when no electric exciting was proposed for a moving magnet linear motor with spring magnet fixed for locating the mover to the initial position when motor pull-up. Considering some nonlinear factors, such as material, flux fringing of the air gap, as well as magnetic circuit saturation, some calculations and characteristic analyses on the motor magnet thrust were carried out based on the Finite Element model established. The characteristic of mover axial magnet thrust under electric current excitation versus the position and electric current were calculated and analyzed. At the same time, the magnet thrust characteristic and the restore effect of the mover of a linear motor with fixed spring magnet were closely studied when no electric excitating. The simulated results can verify well the analytical model proposed, and the element finite simulation model established can meet better the design needs of an actual motor at a more extensive range of variable change.