Digital Control System on Bearingless Permanent Magnet-type Synchronous Motors

The bearingless permanent magnet synchronous motor (BPMSM) is an innovational type of motor, which has all excellence of magnetic bearings. The BPMSM is a high-order, nonlinear and strong coupling multivariable system. Bearingless motors have a set of torque windings and a set of additional suspension force windings in the stator slots. In order to realize the rotor suspending and motor operation steadily, decoupling control between the radial forces and torque force is the chief precondition. In the paper, based on the basic working principle of BPMSM, the mathematics models of the radial forces and rotation part on BPMSM are deduced by adopting rotor magnetic field oriented control (FOC) strategy. A digital vector control system according to the demand of decoupling is designed by using DSP (TMS320LF2407) technique. The hardware and the software of the digital control system are developed in this paper. The experiment results have shown that the steady suspension of the rotor is realized and the speed of the rotor can be continuously adjusted within the range of 0-5000 r/min