A Novel Variable-Flux Permanent-Magnet Synchronous Machine With Quasi-Series Magnet Configuration and Passive Flux Barrier

The hybrid variable-flux permanent-magnet synchronous machine (VF-PMSM) is an alternative candidate for adjustable speed applications. The series magnet and parallel magnet configurations are the two existing topologies for hybrid VF-PMSMs. However, they both have drawbacks that have not been fully resolved. A premium topology with high power density and magnetization regulation using acceptable current pulses is highly desired. This paper proposes a new hybrid VF-PMSM with a quasi-series magnet configuration and a passive flux barrier. After introducing the proposed topology and its operating principles, the results of a comparative study are presented comparing the magnetization characteristics and torque capabilities of the three configurations. The influences of key design variables on the machine's performance are investigated, showing that the proposed machine can achieve a relatively high power density comparable to the series configuration, and the required magnetization current amplitude falls within acceptable limits.