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Design and Implementation of an Observer-Based Controller on a 3-Pole Active Magnetic Bearing Test Rig

Darbandi, Mahdi | 2015

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 47448 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Behzad, Mehdi; Mehdigholi, Hamid; Salarieh, Hassan
  7. Abstract:
  8. Magnetic bearings have been used in industry to achieve an acceptable performance, high precision and vibration suppression of rotating machinery in recent decades.The absence of physical contact between the bearing and rotating components provides access to high rotational speeds which is a problem in conventional bearings.In addition, capabilities such as stiffness and damping adjustment can be used to reduce the harmonic vibrations caused by mass unbalance. The unbalance compensation is one of the main topicswhich has attracted the attention of many researchers in the field of rotordynamics. The aim of this thesis is to design and fabricatea three-pole active magnetic bearing test rig and to propose an algorithm for attenuating the harmonic oscillations caused by mass unbalance. In this study, the integral sliding mode and LQG control techniquesare suggested to stabilize the three-pole magnetic bearing. The performance of these methods is evaluated by simulation and experimental results. Then, the sources of harmonic disturbances are identified in the experimental system and two algorithms are presented to attenuate the harmonic oscillations in the system. In the first one, an integral adaptive observer is used to identify and eliminate the harmonic disturbances. The stability of the closed-loop system is guaranteed by the Lyapunov law and the observer gain matrix is determined by solving a matrix inequality, in this approach. In the second method, a modified notch filter is presented to reduce the harmonic oscillations. The stability analysis is performed in the frequency domain and the parameters of the filter are calculated by the gain and phase margin criteria. Finally, the performance of both methods is validated and discussed using the simulation and experimental results
  9. Keywords:
  10. Active Control ; Magnetic Bearing ; ROTOR ; Linear Quadratic Gaussian (LQG)Controller ; Three-pole Magnetic Bearing ; Unbalance Compensation

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