Magnetic field structure of permanent magnet linear synchronous motor for reduction of thrust ripple

It is difficult to apply the thrust ripple reduction method to a 4-pole 3-slot permanent magnet linear synchronous motor (PMLSM). This paper describes about a new method of the thrust ripple reduction by using the magnet and the ferromagnetic block affixed to its airgap surface divided into five parts. The validity of the five division method is proved by comparing with the results when the movable member is subjected to the normal type skew and the fletching type skew known as thrust ripple reduction method.