Control Technology Of Bearingless Permanent Magnet Synchronous Motor And Magnetic Bearing In The Axial Direction

A bearingless permanent magnet synchronous motor (BPMSM) is an innovational type of motor which integrates magnetic levitation technology with pennanent magnet synchronous motor. There are two kinds of windings embedded in the stator's slot, which is torque windings and suspension force windings. The torque windings can make the motor rotate and the suspension force windings can make the rotor suspend. The BPMSM, which has excellent characteristics of no mechanical friction, needless lubrication and little wear, has potential application prospects in the fields of aeronautics and astronautics, life science, et al. Many research departments have paid more attention to bearingless motor in the world. The main contents of the dissertation are as follows:1. The basic operation principle of the BPMSM is expounded based on analyzing the way of producing suspension forces in the motor, and mathematic models of the BPMSM with the pole pairs of P_M =1 and P_B=2 are deduced. The BPMSM is a strong-coupled, multivariable and complicated nonlinear system, how to realize the decoupling control between electromagnetic torque and radial suspension force is the premise of motor's steady operation, the control method of rotor flux orientation based on SVPWM is adopted, and the control system of the BPMSM is designed, the reality of the proposed method is testified by modeling simulation with the MATLAB software.2. The theroy and practice of the magnetic bearing in the axial direction of the BPMSM are researched. The structure and working principle of the axial hybrid magnetic bearing are introduced and its mathematic models are deduced. The categories, topological structure and control stategy of power amplifier are introduced in detail. A kind of integrated two-level PWM switching power amplifier is designed. On this basis, the control system of the magnetic bearing in the axial direction of BPMSM is designed using axial displacement detection circuit and analog PID controller. The control system is debugged, and the results show the rationality and validity of the design.3. The digital control system using the chip TMS320LF2407A DSP of TI company as the digital controller of the BPMSM is designed. The hardware system based on IPM and the software system under the software development environment CCS2000 are introduced, related program flow charts are given. The hardware and software of the digital control system of the BPMSM with two degrees of freedom is debugged. Some experiment results are given and analyzed, the results demonstrate the correctness of the proposed theroy.