Loading...

Design and Implementation of a Robust Control Method for Rotor Tabilizing in a Three-pole Magnetic Bearing

Khansari, Saed | 2014

1294 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 46422 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Behzad, Mehdi
  7. Abstract:
  8. High speed and high accuracy are two of the major trends for many systems in the 21st century, such as machine tools and semiconductor equipment. For the purpose of high speed, it is well known that active magnetic bearing (AMB) is an inevitable substitute for conventional bearings. The noncontact nature of AMB brings up many advantages over the conventional bearing, including energy efficiency, low wearing, long life span, and absence of lubrication. Hence, AMBs are especially essential for high-speed rotating devices nowadays.
    While the 3-pole AMB has been proposed for many years, it received little attention due to the magnetic coupling between poles that makes the 3-pole AMB system strongly nonlinear. Due to inherent instability, active control is necessary for a 3-pole AMB system.
    In this work we design, analyze and compare the performance of various stabilizing robust controllers for the model of a horizontal rotor with 3-pole active magnetic bearings. Rotors suspended with magnetic bearings are inherently unstable; therefore, feedback control is an essential part of their operation. Despite the nonlinear form of the actuator (electromagnetic bearing) dynamics, plant (rotor) model is linear and time-invariant at constant rotor speed. Actuator dynamics are linearized around an operating point using a constant bias current. Two robust optimal control are designed for the nominal system using different structures.
    optimal controller and -synthesis are three robust controller that are compared in this work based on numerical and experimental results
  9. Keywords:
  10. Linearization ; Robust Control ; Active Magnetic Bearing (AMB) ; M-synthesis Method ; H-infinity Method

 Digital Object List

 Bookmark

No TOC