Torque Enhancement of an Axial Flux Permanent Magnet Synchronous Machine with Asymmetrical Rotor Configuration

An asymmetric axial flux permanent magnet synchronous machine (AAF-PMSM) with shunted magnetic bridges (SMBs) between adjacent rotor permanent magnets is proposed in this paper. The proposed asymmetric rotor structure can effectively increase the maximum output torque without increasing the magnet usage, which is achieved by the magnetic-field-shifting (MFS) effect and the increase of reluctance torque. The comparison between the AAF-PMSM and the conventional axial flux permanent magnet synchronous machine (AF-PMSM) verifies that the proposed design can obtain a torque enhancement as large as 10%.