Studies to decrease cogging force and pulsating thrust in the prototype linear permanent magnet Vernier motor

Vernier motors are known as a large torque machine. Its feature is most suitable for linear direct drive system. However, in general, linear machines have a large cogging force and pulsating force, due to the end-effect. Therefore, the authors have studied an improvement of the force characteristics in a linear permanent magnet vernier motor, which is the type that has small magnets on both the stator and the mover. This paper, first, shows an investigation for reducing the cogging force and its results. Next, the cause of the pulsation force that arises in load running and its improvement are shown. As the result of the improvements, the good force characteristics that include only slight cogging and pulsation force have been obtained.