Study of the Electromagnetic and Mechanical Properties of a High-silicon Steel for a High-speed Interior PM Rotor

High-speed operation is one of an important developments of the electric machines. Currently, surface-mounted PM rotor is more commonly employed than interior PM rotor in the high-speed PM motors. However, the high-speed surface-mounted PM rotor needs a sleeve to protect the rotor from centrifugal force. This brings a series of problems, such as much higher eddy current losses in the metal sleeves and PMs, poor flux weakening ability and so on. In order to avoid sleeves for the high-speed PM rotors, a high-strength and low-losses rotor core for an interior PM rotor is in need. This paper studies the electromagnetic and mechanical properties of a high-silicon steel 10JNEX900 and uses the tested data to design an example motor. The performances of the example motor in terms of electromagnetics, mechanics and temperature are fully studied.