A Novel Magnetic-Field-Shifting Method for Improving the Torque Density of Interior Permanent Magnet Machines

In this paper, a novel magnetic-field-shifting (MFS) method for an interior permanent magnet (IPM) machine is proposed to improve torque performance. By the superposition of the d-axis and q-axis permanent magnetic fields, the permanent magnetic field is shifted to 45° axis apart from origin position, d-axis normally. After using the proposed method, the reluctance torque and permanent magnet torque can obtain maximum simultaneously. Therefore, the torque density of the IPM machine can be improved, and more flexible topology design method can be achieved.