Reduction of Ripple Torque in Permanent Magnet Motors without Skewing

We and Professor Slemon, University of Toronto, have proposed a method of reducing ripple torque in permanent magnet motors without skewing. The ripple torque for a given range of stator current can be substantially reduced by sifting the pole pairs by half a slot pitch and by choosing the value of magnet width so as to minimize the second-order component of cogging torque.