Finite Element Analysis And Control Technology On Bearingless Permanent Magnet Slice Motor

In the research area of the bearingless motors, the bearingless permanent magnet slice motor (BPMSM) has inherited the basic characteristics of the bearingless motor. It can not only generate electromagnetic torque to drive the load, but also generate radial suspension force to realize suspension of the rotor. In particular, its structural characteristics of thin shape of the rotor can realize passively 3-freedom-degree evitation. The BPMSM has important application value in the field of ultra-clean liquid transport because of its advantages such as simple structure, no contact and no wear. Under the support of the High Technology Research of Jiangsu Province (BG2005027), the BPMSM is analyzed and calculated using the finite element ANSYS software. The hardware of power amplifier or the control system is thoroughly studied. The digital control system hardware is designed, and the software is developed, the experimental debugging is carried out. The research contents are as follows:1. The basic structure and working principle of the BPMSM are introduced. The mathematical model of the radial suspension force is established in case of rotor off-center. The method of rotor flux orientation control is adopted to design the torque and radial suspension force decoupling control system, and the block diagram of decoupling control system is given.2. Based on the principle of the Finite Element, 2D magnetic fields are analyzed to validate the principle of radial suspension forces generated by the finite element ANSYS software. The relationships among the radial suspension forces and the currents of radial suspension winding, and the relationships between the radial suspension forces and permanent magnet radial thickness are analyzed and calculated respectively. The research results provide the basis for optimal design of the motor structure.3. According to the control requirements for the 4kW BPMSM, the selection of the power switch thyristor, rectifiers and filter capacitor is considered.The focal point are the hardware design of power inverter circuits, opto-isolation circuit, fault protection circuits and so on.4. The digital control system of the BPMSM is designed and simplified based on the rotor flux oriented vector control method and mathematical models of the BPMSM. TMS320LF2812 of TI Corporation is used in hardware design, and the software of the digital control system is developed. The digital control system is debugged and optimized. The experimental results of digital control system are given and analyzed. The results validate the correctness of the control system and the control strategy.