Design Optimization Procedure of Air-Cored Resonant Induction Machines

The air-cored resonant induction machine removes the iron core which makes its magnetic field truly 3-D in nature. The axial conductors and end windings now both become active components contributing to torque production. The whole winding therefore needs to be considered in the design process. Conventional 3-D finite element analysis has large computational costs and is hard to integrate into the design optimization. This paper presents a new design optimization procedure for air-cored resonant induction machines using closed-form solutions of Neumann integrals which are computationally fast and considers the 3-D magnetic field distributions created by the air-cored coils. Optimized designs for two tuning options in the literature: option I with stator capacitors only and option II with both stator and rotor capacitors, are presented. The optimization trends with respect to different machine parameters are also discussed.