Modular stator structure permanent magnet synchronous machine

A new type of three-phase permanent magnet synchronous machine (PMSM) with modular stator structure is proposed. Its structure and principle is introduced. The machinepsilas teeth width is equal to polar pitch, its stator winding is concentrated winding, each phase winding is wound up continuously and the ends of windings are shorter then conventional machines. Therefore, the machinepsilas efficiency is increased and mass is reduced proportionally. The relation between structure parameter and pole number is discussed. It is also approved that only the 3rd and integral times of 3rd cogging torque is existed and the others are eliminated. A 22-pole prototype machine, of which magnets are mounted on the rotor surface (is equipped with surface-mounted magnet rotor), is analyzed by finite element method, and calculated result proved that phased inductive electromotive force(EMF) wave of three phase stator winding is shape of trapezoid, and the top flat waveband of EMF approaches to 2pi/3 electrical angle. And the prototype machine, in term of brushless direct current motor (BLDCM), is analyzed and correlative result is discussed when it is at full load. This kind of permanent magnet synchronous machine with new stator structure is especially suitable for the field of low speed BLDCM and direct driven wind turbine with PMSM.