Adjustable Field PM Motor Based on Permeability Modulation Technique Using Zero-Phase Current

An adjustable field magnetic flux permanent magnet (PM) motor is proposed in this paper, which is based on a permeability modulation technique. The proposed PM motor has magnetic paths made of soft magnetic metal between the permanent magnet poles in the rotor, and a special coil for the permeability modulation of the soft magnetic metal. The proposed PM motor can control the amount of the leakage flux between the rotor permanent magnet poles by means of magnetic saturation of the soft magnetic metal, where the main magnetic flux interlinking to the stator windings is effectively reduced because the leakage flux between the permanent magnet poles is dominant. However, when the soft magnetic metal is magnetically saturated by the zero-phase magnetic flux, the leakage magnetic flux is reduced, resulting in the enhancement of the main magnetic flux to the stator. This paper demonstrates computer simulation results of the proposed strategy for the adjustable field magnetic flux PM motor.