Study of stator structure to improve reluctance torque for IPMSM with concentrated winding

Interior permanent magnet synchronous motors (IPMSMs) that employ rare-earth magnets are high-performance motors and are used in many applications. However, it is desirable to reduce the number of rare-earth magnets used in IPMSMs because of the high cost. If a non-rare earth magnet is used in IPMSMs with concentrated windings, the motor generates reluctance torque principally; however, this reluctance torque is significantly decreased. Therefore, it is necessary to improve the reluctance torque in concentrated-winding IPMSMs. In this study, we aim to improve the reluctance torque for IPMSMs with concentrated windings by investigating the stator structure. The influence of the length and thickness of the pole horn on reluctance torque is examined and suitable lengths and thicknesses of a pole horn are clarified by finite element analysis.