LMI approach to gain scheduled H/sub ∞/ control beyond PID control for gyroscopic rotor-magnetic bearing system

2002 ◽  
Author(s):  
S. Sivrioglu ◽  
K. Nonami
Keyword(s):  
Pid Control ◽  
Magnetic Bearing ◽  
Lmi Approach ◽  
Gain Scheduled ◽  
Bearing System

Analysis and Testing of a Magnetic Bearing Energy Storage Flywheel With Gain-Scheduled, MIMO Control

2000 ◽  
Author(s):  
Lawrence A. Hawkins ◽  
Brian T. Murphy ◽  
John Kajs
Keyword(s):  
Energy Storage ◽  
Dynamic Test ◽  
Magnetic Bearing ◽  
System Stability ◽  
University Of Texas ◽  
Mimo Control ◽  
Cross Axis ◽  
Five Axis ◽  
Gain Scheduled ◽  
Bearing System

The design and initial testing of a five axis magnetic bearing system in an energy storage flywheel is presented. The flywheel is under development at the University of Texas Center for Electromechanics (UT-CEM) for application in a transit bus. The bearing system for the prototype features homopolar permanent magnet bias magnetic bearings. The system has been successfully tested to the maximum design speed of 42,000 rpm. A gain-scheduled, MIMO control algorithm was required to control the system modes affected by rotor gyroscopics. The implementation and basis for this control scheme is discussed. The cross-axis forces produced by this approach are described in terms of circumferential cross-coupled stiffness and damping to explain the effect on system stability. Dynamic test results are discussed relative to the rotordynamic and control system design.

An anti-windup control strategy to actuator saturating input voltage for active magnetic bearing system

2016 ◽  
Vol 35 (3) ◽  
Author(s):  
Avadh Pati ◽  
Richa Negi
Keyword(s):  
Control Strategy ◽  
Pid Control ◽  
Input Voltage ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Region Of Attraction ◽  
Control Scheme ◽  
Amb System ◽  
Voltage Saturation ◽  
Bearing System

Purpose The active magnetic bearing is highly nonlinear and unstable system. In general most of physical systems, conventional PID control strategies are employed for their stable operation but the dynamics of the system are influenced by input voltage saturation that degrades the performance of the system. The conventional PID control scheme does not work properly alone. In such a situation, PID faces windup phenomenon that leads to instability in the system. To overcome this problem, an anti-windup control scheme leads to stable and smooth operation of active magnetic bearing system. Design/methodology/approach The proposed anti-windup control strategy is based on dynamic output feedback that is applied on linearized active magnetic bearing (AMB) system to stabilize and avoid the input voltage saturation effect in the actuator. Findings An anti-windup controller is designed for active magnetic bearing system in presence of input voltage saturation. The stability of AMB system with anti-windup controller is derived in sense of Lyapunov and expressed as linear matrix inequality problem for AMB system and the designed anti-windup controller also enlarges the region of attraction of considered AMB system. Originality/value T-S fuzzy technique is used for obtaining local linear model of nonlinear active magnetic bearing system for easy and simple implementation of anti-windup control scheme. In proposed methodology the region of attraction for anti-windup compensator is also discussed. The effectiveness of proposed method is verified by the numerical simulation results for considered active magnetic bearing system and domain of attraction or stability region of closed loop AMB system are also calculated using Eigen Value Optimization technique for both the cases such as with and without anti-windup controller. The comparative result and the contribution of proposed control strategy are also discussed.

scholarly journals Nonlinear Behavior of a Magnetic Bearing System

1995 ◽  
Vol 117 (3) ◽  
pp. 582-588 ◽  
Author(s):  
L. N. Virgin ◽  
T. F. Walsh ◽  
J. D. Knight
Keyword(s):  
Degrees Of Freedom ◽  
Initial Conditions ◽  
Nonlinear Behavior ◽  
Analytical Techniques ◽  
Magnetic Bearing ◽  
Forced Response ◽  
The Mathematical Model ◽  
Two Degree Of Freedom ◽  
Sensitivity To Initial Conditions ◽  
Bearing System

This paper describes the results of a study into the dynamic behavior of a magnetic bearing system. The research focuses attention on the influence of nonlinearities on the forced response of a two-degree-of-freedom rotating mass suspended by magnetic bearings and subject to rotating unbalance and feedback control. Geometric coupling between the degrees of freedom leads to a pair of nonlinear ordinary differential equations, which are then solved using both numerical simulation and approximate analytical techniques. The system exhibits a variety of interesting and somewhat unexpected phenomena including various amplitude driven bifurcational events, sensitivity to initial conditions, and the complete loss of stability associated with the escape from the potential well in which the system can be thought to be oscillating. An approximate criterion to avoid this last possibility is developed based on concepts of limiting the response of the system. The present paper may be considered as an extension to an earlier study by the same authors, which described the practical context of the work, free vibration, control aspects, and derivation of the mathematical model.

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