Comparison of Characteristics of Double-Sided Permanent-Magnet Synchronous Motor/Generator According to Magnetization Patterns for Flywheel Energy Storage System Using an Analytical Method

The flywheel energy storage system (FESS) is a very promising energy storage technology used in recent years because of its advantages, such as high energy density and large instantaneous power. In the case of a permanent-magnet (PM) synchronous motor/generator (PMSM/G) used for driving the FESS, a reduction in torque ripple is necessary because operating ranges are high speed. In this paper, we study the use of a double-sided PMSM/G for driving the FESS to considerably reduce iron loss that occurs in the idling mode. To develop an appropriate model for sinusoidal wave operation, we compare the characteristics of a double-sided PMSM/G having a Halbach magnetized PM and a parallel magnetized PM using an analytical method. On the basis of the compared results, the most suitable model for sinusoidal wave operation is manufactured.