A new approach to establishing a dynamic and control model for Slotless Self-Bearing Motor

Abstract

The content of the article analyzes the electromechanical process of the Lorentz electromagnetic force when we supply a slotless self-bearing motor with two types of current: alternating current and direct current. The alternating current generates motor torque and the direct current generates axial magnetic drive force. The slotless self-bearing motor model designed and fabricated in this study has a concentrated rotor magnetic field and scattered stator windings. This is different from previous research models where the rotor has a distributed magnetic field and the stator is 12 bars. The new type of motor in the study of this paper uses the vector control theory of electric machines to build the control model. In this motor, the magnetic drive force will be maintained continuously by a direct current large enough to hold the rotor against disturbances caused by centrifugal force when the motor rotates and disturbances due to rotor drag. The control structure for the slotless self-bearing motor is cascaded. The inner loop is a current loop that is designed in a “bang-bang” control structure. The outer loop circuit has two channels: the position control channel and the speed control channel. The position control channel uses a PD controller combined with feedforward noise compensation and the speed channel uses a PI controller. The simulation results show that the system works stably and is resistant to noise for the rotor position.