Rotor Suspension Principle and Decoupling Control for Self-bearing Induction Motors

In this paper, a self-bearing induction motor with additional windings in the stator slots is proposed. The self-bearing induction motor is a strong coupled, multivariable and nonlinear system. The torque and radial suspension forces are coupled each other through airgap flux linkages. The decoupling control of the torque and radial suspension forces is the base of the stable operation of the motor. In this paper, the principle of radial suspension forces is introduced. The mathematics models of radial suspension forces and the rotation part of the motor are deduced. A control system based on rotor magnetic field oriented control strategy is designed. The control system is simulated using Matlab/Simulink toolbox. Simulation results have shown that the rotor can suspend steadily, torque and radial suspension subsystems can be controlled independently, the control method is valid and the whole control system has satisfactory static and dynamic performance