Design and Analysis of 1 MW Synchronous Machine via 3D Magnetic Field Calculation

A 1 MW class superconducting synchronous rotating machine has been designed as a draft based on 2-dimensional (2D) magnetic field distribution considering several conditions such as superconducting wire length, machine efficiency, size and so on. By the way from 2D design it is not possible to consider the effect of end coils and end portions of stator iron yoke especially in superconducting machine with air-cored structure which increases magnetic field difference between 2D and 3D analysis. In this paper electrical design based on the 3D magnetic field distribution is conducted to get more proper design result and reduce design errors from 2D design approach. As the machine has larger capacity, the superconducting machine will show the advantages more and more over the conventional machine. Although the advantages at 1MW rating are not so great, the 3D design approach to get more optimized result would be very helpful for larger superconducting synchronous machine design. Through 3D analysis such as EMCN (equivalent magnetic circuit network) method and Flux-3D FEM (finite element method), we could get smaller machine size, higher efficiency, and smaller Bi-2223 HTS (high temperature superconducting) wire length than the 2D design result. Moreover influence of an important parameter, synchronous reactance, has been analysed on the machine performances such as voltage variation and output power.