A Novel Hybrid-Pole Interior PM Machine with Magnet-Axis-Shifting Effect

This paper proposes a novel hybrid-pole interior permanent magnet (HP-IPM) machine by combining dual-layer reluctance and flat-type PM structures. The design concept of “asymmetrical magnet arrangement” is introduced to achieve a magnet-axis-shifting (MAS) effect, namely, the PM d-axis is shifted to make PM and reluctance torque components maximize at the same current angle. Consequently, the resultant torque is improved without increasing magnet usage. The machine topology and MAS effect are first introduced, respectively. In addition, the design optimization is performed to maximize the total torque capability. The electromagnetic characteristics of the proposed HP-IPM machine are investigated and compared with those of the reference conventional IPM machine with similar sizing and PM usage, which confirms the feasibility of the proposed HP design for the torque performance improvement.