Electromagnetic design of high-speed permanent magnet synchronous motor for flywheel energy storage system

Flywheel energy storage system (FESS) has significant advantages such as high power density, high efficiency, short charging time, fast response speed, long service life, maintenance free, and no geographical environment restrictions. Motor is the energy conversion core of FESS and plays a significant role on system performance. In this paper, the design features of the motor for FESS are analyzed first. Then, a permanent magnet synchronous motor (PMSM) with a rated speed of 12000 rpm and a rated power of 250 kW is designed. Thirdly, aiming at the key problem of difficult heat dissipation of rotor, an improved rotor structure with "1" rotor permanent magnets layered and divided where placed in tangential and radial directions is proposed, which can reduce eddy current loss by 22.8%. Finally, based on Ansys FEM software, electromagnetic characteristics of the designed motor at no-load and full-load conditions are simulated and analyzed. The results show that the designed electromagnetic scheme meets the expected performance requirements and has guiding significance for prototype. (paper)