Future trends in the application of (RE)BCO in electrical machines

Bulk YBCO has been used in prototype electrical machines over the last decade. The output power of such machines has increased from a few watts to over 20 kW. However, the promise of dramatically increasing the power density as compared to conventional machines has not been achieved by existing prototypes. One of the major limitations is that the material has not been exploited to its full potential in existing designs. This paper considers the key parameters that determine the flux generating potential of (RE)BCO conductors for application in electrical machines of existing and new designs. In comparison with permanent magnets, the five-fold increase in power density of currently available bulk (RE)BCO materials, which translates directly to increased operating flux density, underlines their potential for applications. Future developments should focus on increasing the trapped flux in large grain (RE)BCO samples and on developing joining techniques to enable fabrication of a variety of shapes suitable for machine applications.