Effect of Magnetic Property in Bridge Area of IPM Motors on Torque Characteristics

This paper investigates the deterioration effect of magnetic properties on the performance of an interior permanent magnet synchronous motor (IPMSM). It is well known that the magnetic property of an electrical steel sheet is deteriorated by stress, which results in a decrease in efficiency of electric machines in general. In this paper, by making good use of the deterioration of magnetic properties, the performance improvement of IPMSMs due to the reduction of leakage flux in a rotor is examined. As a result, it is verified that cogging torque can be decreased by half by deteriorating magnetic property in bridge area in a rotor without reducing average torque and increasing iron loss at load condition.