Development of large salient-pole synchronous machines by using fractional-slot concentrated windings

This paper presents a detailed analysis and comparison of large salient-pole synchronous generators (SPSG) with conventional slot distributed and fractional slot concentrated winding techniques for power generation applications. The fractional slot concentrated winding technique (FSCW) makes it possible to increase the machine inductance and permeability of the poles in order to achieve lighter, cheaper and high-efficiency SPSGs with a simpler structure without reducing the output power. The SPSGs are modeled and analyzed by using ANSYS MAXWELL packet program which is a Finite Element Method (FEM) based electromagnetic field simulation software. Detailed comparisons of the SPSGs' performance characteristics which include important issues such as wave form of the induced voltage, weight and cost of the machines, machine losses and saturation effect are presented. Guidelines are developed to help electrical machine designers faced with reducing the saturation of the SPSGs' poles.