High Temperature Superconducting Halbach Array Topology for Air-cored Electrical Machines

Abstract

Air-cored electrical machines have attracted increasing attention in applications related to aircraft and wind power because they can eliminate core losses and decrease the total mass. However, the limited magnetic flux in air-cored machines has restricted their power level. In order to improve the power density and efficiency while further reducing the weight of air-cored electrical machines, a novel field winding topology composed of high temperature superconducting (HTS) Halbach Array magnets (HAM) has been proposed in this paper. C-GEN is an innovative multi-stage air-cored generator technology with permanent magnets, which has been demonstrated at laboratory scale. Taking a 1 MW C-GEN generator prototype as the example machine, an H -formulation founded HTSHAM model has been built in COMSOL Multiphysics with the homogenization method. Simulation results show that the proposed HTSHAM C-GEN generator can achieve a power density more than 4 times higher than the conventional design with permanent magnets (PM), with a reduced magnet weight of around half of the previous prototype. The proposed HTSHAM represents a generic approach for the design of fully air-cored superconducting synchronous machines, eliminating heavy ferromagnetic material, and thus provides a useful reference for the design of low-weight air-cored electrical machines with a high power density.