Patent ID: 6867524
Filing Date: 2005-03-15
Classification: H02K

Abstract:
1. A permanent magnet rotor comprising: at least three rotor segments formed sequentially adjacent along an axis of the rotor, wherein each of the at least three rotor segments includes at least one pair of permanent magnets disposed at a substantially equal interval in a peripheral direction of the rotor; a first angular displacement formed between a first and second segment of the at least three rotor segments; a second angular displacement formed between the first and a third segment of the at least three rotor segments; wherein the first and second angular displacements are selected to cause a net sum of torque ripple produced by each of the at least three rotor segments to be substantially equal to zero during an operation of the rotor; and wherein the second rotor segment has an axial length approximately equal to one half of a total rotor axial length, wherein each of the first and third rotor segments have an axial length approximately equal to a quarter of the total rotor axial length.