Title :
A method of reducing ripple torque in permanent magnet motors without skewing
Author :
Ishikawa, Takeo ; Slemon, Gordon R.
Author_Institution :
Dept. of Electron. Eng., Gunma Univ., Japan
fDate :
3/1/1993 12:00:00 AM
Abstract :
A method of reducing ripple torque, i.e., the sum of cogging and commutation torques, in permanent-magnet motors without skewing is proposed. The ripple torque for a given range of stator current can be substantially reduced by shifting 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 the cogging torque. The method is confirmed by the finite-element analysis of permanent-magnet motors with both radially magnetized and parallel-magnetized magnets. The optimal magnet width of the experimental motor is 6.18 slot pitches for the radially magnetized magnets and 5.80 slot pitches for parallel-magnetized magnets
Keywords :
finite element analysis; permanent magnet motors; synchronous motors; torque control; cogging torque; commutation torques; finite-element analysis; optimal magnet width; parallel-magnetized magnets; permanent magnet motors; radially magnetized magnets; ripple torque reduction; Finite element methods; Forging; Magnetic analysis; Magnetic flux; Permanent magnet motors; Permanent magnets; Rotors; Stators; Teeth; Torque;
Journal_Title :
Magnetics, IEEE Transactions on
