Characteristics of torque and suspension force in a consequent-pole bearingless motor

By building a finite-element analysis model, the principle of magnetic levitation and torque characteristic were analyzed and demonstrated. The simulation results suggest that torque is in proportion to torque current and radial force is in proportion to suspension current. Meanwhile, rotational angular position is not necessary in the magnetic suspension control and the decoupling control of the levitation and torque can be realized. For the compromise between radial suspension force and drive torque in the traditional bearingless motor, respectively two models of former motor and surface-mount bearingless motor are established. As a result, the consequent-pole generates suspension force 2.87 times more than the latter when their torque is close.