Direct torque and suspension force control for bearingless permanent magnet synchronous motors

The bearingless permanent magnet synchronous motor is a strong-coupled nonlinear system. To solve the difficult problem of precise decoupling control, the theory and method of direct torque control of traditional permanent magnet synchronous motor are applied to the torque control of a bearingless permanent magnet synchronous motor in the paper. With the reference of direct torque control of traditional permanent magnet synchronous motor, a double closed-loop control system of rotor radial displacement and radial suspension force is constructed to control the radial suspension force directly. A direct torque and suspension force control algorithm based on space vector pulse width modulation strategy is deduced, the direct torque and suspension force control system is designed and simulated by MATLAB. The control system is simple and robust. The simulation results have shown that the rotor can be suspended stability, the control algorithm performs very good decoupling in torque and radial suspension force control and torque and radial suspension force subsystems can be controlled independently, the control method is valid and the control system has a good static and dynamic performance.