Similarity laws in low speed switched reluctance machines design

This paper presents a set of similarity laws appropriate for low speed switched reluctance machines design. Design methodologies of switched reluctance machines for low speed applications are generally oriented towards the choice of suitable combinations of stator and rotor poles in regular topologies. The proposed similarity laws provide an easy-to-use and robust methodology to compare different magnetic topologies, regular or non-regular, and have the capability to incorporate thermal and magnetic saturation phenomena by introducing constraints. With the assistance of finite-element analysis the issues surrounding the design of low speed SR multi-machines topologies are discussed, leading into consideration of modular non-regular topologies. Using similarity laws, the modular topology is compared with a regular switched reluctance machine. The comparison results point out the reduction of copper losses of the modular topology over the regular topology. This paper extends previous discussions of switched machine design into a more general context.