Interior composite-rotor controllable-flux PMSM - memory motor

A new class of interior composite-rotor controllable-flux permanent magnet synchronous machine (PMSM) for true wide-speed operation is proposed. It can operate in wide-speed without overmuch armature loss and sacrifices in other machine characteristics. The tangential-set permanent magnets (PMs) are NdFeB that has high remanent flux density B_r and high coercive force H. The radial-set PMs are AlNiCo that has high B_r and low H. By applying the pulse of d-axis stator current vector i_d, the magnetized intensity and direction of AlNiCo can be controlled. The flux created by NdFeB is repelled by AlNiCo to stator and air-gap PM-flux is intensified, or is partially bypassed by AlNiCo in the rotor and the air-gap PM-flux is weakened. The structure can adapt for memory motor with more pole-pairs. The interior magnetic field distribution in two extreme magnetized conditions was analyzed by finite element method. And the proposed assumption is proved.