Optimization Of Motor Design And Control System Of Bearingless Slice Motors

The bearingless slice motor (BSM) is a new-type electrical machinery, which can completely suspend at 5 DOF. It utilizes the bearingless technology to realize radial suspension, and can be levitated passively by the magnetic force at the same time. For its advantages like non-abrasion, robustness, simple structure, hermetical, and so on, the BSM has unique application superiority in the fields of ultra-pure driving, such as medical equipment, chemical industry, nuclear waste material, etc.In the case of eccentricity, the mathematical model of the BSM is discussed in this paper, which is helpful for solving the problem of confirming the central position of the rotor. The mathematical model provides theoretic foundation for the control system design. The finite element analysis (FEA) software, ANSYS, is adopted to analyze the radial force and torque. The simulative results validate the validity of the mathematical model with the rotor having radial displacements.In the aspect of motor design, two optimize methods of designing the permanent magnet shape, which aim at parallel and radial magnetization respectively, are introduced in detail. Compared with the conventional surface-mounted permanent magnet type, the new shape can produce sine air-gap flux density and thus alleviate the overtone content. The simulative results and the experimental results prove the feasibility of the optimize methods. Also, the methods make reference to the permanent magnet design, which can produce other forms of air-gap flux density like rectangle and trapezium. Moreover, the research on electromagnetic simulative analysis of the axial force and torsion is beneficial to improve the motor design and the in-depth study on passive suspension.Based on the mathematic model of eccentricity and the electromagnetic simulative analysis above, this paper also studies on the digital control software system with———————— TMS320F2812 DSP. The subprograms are modularized, which can predigest the codes length and save the memory space. Applied to a BSM adopted optimized permanent magnet, the software system codes are designed, compiled and debugged. The experimental results indicate that the motor can be suspended and rotated successfully.