New Structures of Polyphase Claw-Pole Machines

Abstract

New structures of motor magnetic circuits can be realized by use of the soft magnetic composites. This paper presents new claw-pole motors with a polyphase winding and a standard cylindrical rotor which use these isotropic materials. A division of the stator magnetic circuit into three parts and the use of a centralized-concentrated winding with a small number of coils simplify the production process, the mechanical assembly, and the winding realization. With these special stator geometries, the electromagnetic, mechanical and thermal functions are integrated into the same stator parts. This integration is much better than in a classical two-dimensional (2-D) structure using a laminated material. There is no end winding and the copper volume can be minimized. The size of the additional parts which are necessary for the bearing housings and the mechanical fixation of the rotor are reduced. These structures can be equipped with an integrated cooling system, with efficient air convection or water circulation. This paper describes the design approach of these original structures. It demonstrates that such three-dimensional (3-D) structures can be derived from their equivalent 2-D structures with a concentrated winding. The concept and the design approach are validated by the realization and the comparative experimental tests of two prototypes with a 3-D and its equivalent 2-D structure.