Research On Digital Control System Of AMB Based On DSP

Active magnetic bearing (AMB) is a kind of novel high-performance bearing, in which rotor can be suspended stably by controllable magnetic force and realize contact-free property between rotor and stator. Due to its advantages of no friction, no wear, no lubrication and longevity, AMB has vast and promising applications in the following high-tech fields: aviation, vacuum technology, machine tool, tail-wagging engine, etc.Dynamic performances (stiffness, damp, stability, etc.) of AMB are mostly rested with the rules of controller. Adopting preferable controller and control rules can greatly improve dynamic performances of control system. This research designs a digital control system based on TMS320LF2407A DSP for the sake of improving the capability and reliability of AMB and diminishing the cubage of controller. Through experimental debugging, the rotor is suspended steadily in 5 degrees of freedom. IIR filter is discussed theoretically and designed for AMB.First, the thesis discusses the basic work principle of AMB and the mechanism structures of the principal axis, analyzes the expressions of Magnetic field and electromagnetism force, deduces the mathematic model based on the expression, and hence, the linear model of AMB, and introduces the close loop frame of the control system; And the following presents further research on the hardware frame of the digital control system of AMB, especially the design of the DSP minimal system, position-acquiring circuit, filter, A/D circuit, D/A circuit, power amplifier; besides, the software frame of the control system is introduced and a detailed flow chart is shown, the debug method of PID control parameter and the scale method are emphasized particularly; finally, some experimental curves are drawn on the basis of vast experiments and researches.The performance of filter is of significance to enhance the control capability of control system of AMB. This paper designs an IIR filter which can be applied to the control of AMB as a low pass with FDATOOL tool of Signal Processing Toolbox in MATLAB. The experimental results have shown that the filter can satisfy the request of the control system of AMB and the filter works well.