Synchronous-hysteresis superconducting machine with stacks of second generation tapes

Superconducting Electric Machines (SEM) have some advantages compared to machines with conventional conductors, such as higher power density, weight reduction, increased efficiency, and higher overload capacity. Those properties make the SEM ideal for several applications where a lighter and smaller machine is necessary. The SEM can be constructed using high temperature superconductor (HTS) bulks with trapped field or with superconducting tapes arranged as coils. Recent works have been proposed to replace the HTS bulk by stacks of second generation (2G) tapes to trap the magnetic field. Electric machines using trapped field in stacks of 2G tapes were not deeply investigated in the literature. In this context, the purpose of the present work is to study a SEM constructed with 2G tape stacks spirally arranged on the rotor. A small-scale SEM prototype was constructed and tested at 77 K in a laboratory bench. The tape stacks can be used in the SEM to operate in the synchronous or hysteresis regime, depending on the torque demanded by the load. Results as quasi-static torque, torque at locked rotor and torque vs. speed are presented. These results can help us to project the next generation of SEM.