Trend of permanent magnet synchronous machines

The performance of permanent magnet synchronous machines (PMSMs) has improved rapidly by the progress in elemental technologies such as electromagnetic material technology, computer-aided design technology, control technique, and drive circuit technology, and thus PMSMs are attractive as high-performance machines in various fields. This paper describes the recent technology and the trends in PMSMs. To begin with the PMSMs are classified by the ratio of magnet torque to the reluctance torque and their features described, then the trend of the motor design and the electromagnetic material for highly efficient PMSM is shown. The technologies that help to reduce the vibration and noise are also described, and the recently developed PMSMs for traction drive application are introduced. (c) 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.