Thrust ripple reduction method of inner magnet linear synchronous motor

A thrust ripple reduction method for a permanent magnet linear synchronous motor is introduced. The mover consisting of a magnet, a ferromagnetic plate, and a back yoke is divided into three parts in the stacking direction. Each part is spatially displaced in the moving direction. The evaluation coefficient of the harmonic thrust similar to the distribution factor of the winding predicts the amount of the displacement for reducing the thrust ripple at the design stage. This method is compared with the case where the mover is skewed. Furthermore, it is estimated that both end parts of the back yoke act as to yield lower harmonic ripple.