Prototyping a Composite SMC/Steel Axial-flux PM Wind Generator

This paper outlines the design and prototyping of an SMC-based axial-flux PM wind generator with a composite SMC/steel stator core. The machine topology has SMC teeth fitted into a laminated silicon steel stator yoke. A simple pressed fit and wedge/retaining ring arrangement is proposed for fixing the SMC teeth into the yoke. The machine is sized based on wind speed requirements and SMC core samples available for the research. Preformed coils are used to form a concentrated, non-overlapping stator winding, which are inserted from the stator yoke side. Consequently, the slot openings are small, thereby reducing harmonics associated with the slot openings. Detailed finite element analysis results are presented for the machine topology under investigation. The SMC cores are machined by means of a cost effective and easily accessible process using an end-mill. A discussion is provided of the detrimental effect of this machining process on the SMC core. However, a chemical processing technique is investigated for treating the smear of the iron particles on the machined surfaces of the SMC core. Microscopic images are shown to illustrate the successful elimination of the smear on the machined surfaces. Assembly of the prototype is discussed in detail and experimental results are provided