Design of a brushless superconducting-field claw-pole machine and Its application in flywheel energy storage system

The flywheel energy storage system (FESS) is a high-performance physical energy storage device that can be used for peak shaving and frequency regulation in power grids, effectively improving grid operational reliability. To address the heating issues of permanent magnet machines in existing FESS devices, a brushless superconducting-field claw-pole machine (BSCM) is proposed to enhance the energy-to-volume ratio of the FESS and solve the heating problem of permanent magnet machines in FESS. Three topologies of brushless electrically-excited claw-pole machines were designed and their performances analyzed and compared. The results show that the 18/20-pole BSCM exhibits the optimal design characteristics. A prototype of the 18/20-pole machine was further developed and experimentally validated, confirming the accuracy of its simulation design. This machine topology was applied to the FESS, and an integrated design was implemented, addressing the heat dissipation while eliminating the use of brushes. Magneto-thermal coupling simulations indicate that the superconducting-machine-based FESS reaches a long-term temperature rise of 59.184°C with a reasonable temperature distribution. This study provides a feasible technical reference for the application of superconducting machines in FESS.