Structure of the PM synchronous motor for low iron loss characteristic in the high-speed region

High efficiency motors driven at high speed are required in various applications. However, these motors suffer from excessive iron loss in the high-speed region. A number of structures have already been suggested for high speed drive. In this research, the motor with the concentrated winding stator and the motor with the slot-less stator are compared with respect to high speed drive characteristics. The speed-power characteristics and speed-efficiency characteristics in the high-speed region of the motors are revealed.