Characteristic analysis on synchronous machine with double-side permanent magnet rotor for flywheel energy storage system in EV

This paper deals with the generating performance evaluation on double-side Halbach permanent magnet synchronous motor/generator (PMSM/G) for flywheel energy storage system (FESS). The exact generating performance evaluation of PMSM/G is necessary, because the PMSM/G should be designed to satisfy the generating power in required speed range. First of all, we present the PMSM/G with Halbach arrayed double-side PM rotor for FESS. In energy storage system such as FESS, this machine has advantage of absence of iron loss. For the generating performance estimation, the back-EMF constant of double-side Halbach PMSM/G is derived by magnetic field analysis using analytical method. From the derived back-EMF constant, generating performance is estimated in the M/G operating system for motoring as well as generating. Finally, analysis and estimation results are verified and evaluated by the generating performance of experimental result for double-side PMSM/G with flywheel.