Suspension principle and control system design for bearingless brushless DC motor

The dynamic decoupling control of electromagnet torque and radial suspension force is the basic condition of stable operation for bearingless brushless DC motors. In this paper, the principle of radial suspension force is expounded. The mathematics models of rotation part and radial suspension force of the motor are deduced. A control system based on rotor magnetic field oriented control is designed. The control system is simulated with Matlab/Simulink toolbox. The simulation results have shown that rotor can suspend steadily, torque and radial suspension subsystems can be controlled independently, the control method is valid and the whole control system has fine static and dynamic performance.