ANALYSIS ON EFFECTS OF FRACTIONAL-ORDER SPACE HARMONICS OF POLE-CHANGING SALIENT POLE SYNCHRONOUS MACHINE

摘要

Harmonic analysis of the magnetic field is used to show that many high amplitude fractional order harmonic components exist in the air-gap magnetic field of pole-changing salient-pole synchronous machines. These fractional order harmonic components may cause high circulating current in parallel connected branches of the stator winding. In order to avoid this effect, the number of parallel branches per phase in the stator windings must be limited in accordance with a relationship between pole numbers which is analyzed in this paper.