Comparison of electromagnetic performance of 10-MW HTS double-stator flux modulation wind generators with different topologies

For conventional HTS synchronous generator, the superconducting (SC) field windings or armature windings are rotating, which could complicate their industrial feasibility for the offshore wind generation. In order to overcome this drawback, a kind of HTS double-stator flux modulation generator (HTS-DSFMG) without rotating windings is proposed. This paper compares the electromagnetic performance of 10-MW HTS double-stator flux modulation generators with two different topologies, i.e., iron-cored stators with both field and armature coils, air-cored stator with field windings and iron-cored stator with armature windings. In addition, the system comparison of HTS-DSFMG with conventional HTS synchronous machine is conducted under the no-load, rated load and short-circuit fault conditions. It is found that the proposed machine can dramatically reduce the peak current and peak torque during a symmetrical three-phase short-circuit fault, and its active material mass and cost are comparable with the synchronous one under rated load condition. Finally, the ac losses analysis of the SC coils for HTS-DSFMGs is conducted and three effective methods are proposed to reduce the ac losses.