Starting and synchronization of permanent magnet hysteresis motors

This paper presents the design, analysis, and application of permanent magnets in a hysteresis motor with a view to improve the overall performance of such motors. The novel rotor consists of 36% cobalt steel alloys with neodymium boron iron permanent magnets. This hybrid design combines the advantageous performance features of both typical permanent magnet motors and conventional hysteresis motors. The machine models for steady-state and run-up performances are derived. Using state variable equations, starting and synchronizing performances are predicted. A 5 hp laboratory prototype permanent magnet hysteresis motor was built. Test results validate the superior performances of the new motor.