Influence of magnet and flux barrier arrangement for IPMSM with concentrated winding

Interior permanent magnet synchronous motors (IPMSMs) are widely used as highly efficient, high-performance motors. In an IPMSM, the magnet is mainly constructed of rare-earth materials. Recently, however, there has been a trend away from using rare-earth materials due to the high cost and the unpredictability involved in procuring such materials. Therefore, development is required of a lower-cost motor that has equivalent performance, even if it has weaker magnetism. Another recent trend is the adoption of a concentrated winding to reduce copper loss and achieve a smaller size. A motor with a concentrated winding, however, has less total torque due to decrease reluctance torque. In an attempt to improve this situation, in this paper the flux barrier angle in the rotor and the arrangement of the magnets are changed to maximize total torque and to increase the ratio of reluctance torque as much as possible. A model of this type of asymmetrical structure with a slanted magnet demonstrates that total torque and the ratio of reluctance torque are greater than the other structures dealt with in this paper.