A Numerical Study on the Effect of Unbalance and Misalignment Fault Parameters in a Rigid Rotor Levitated by Active Magnetic Bearings

2019 ◽  
Author(s):  
Prabhat Kumar ◽  
Rajiv Tiwari
Keyword(s):  
Numerical Study ◽  
Equations Of Motion ◽  
Rotor System ◽  
Magnetic Bearings ◽  
Inertia Force ◽  
Dimensional System ◽  
Rigid Rotor ◽  
Active Magnetic Bearings ◽  
Fault Parameters ◽  
Misalignment Fault

Abstract This paper focusses on analysing the vibration behaviour of a rigid rotor levitated by active magnetic bearings (AMB) under the influence of unbalance and misalignment parameters. Unbalance in rotor and misalignment between rotor and both supported AMBs are key fault parameters in the rotor system. To demonstrate this dynamic analysis, an unbalanced rigid rotor with a disc at the middle levitated by two misaligned active magnetic bearings has been mathematically modelled. One of the novel concepts is also described as how the force due to active magnetic bearings on the rigid rotor is modified when the rotor is parallel misaligned with AMBs. With inclusion of inertia force, unbalance force and force due to misaligned AMBs, the equations of motion of the rigid rotor system are derived and converted into dimensionless form in terms of various non-dimensional system and fault parameters. Numerical simulations have been performed to yield the dimensionless rotor displacement and controlling current responses at AMBs. The prime intention of the present paper is to study the effect on the displacement response of the rigid rotor system and the current consumption of AMBs for different ranges of disc eccentricities and rotor-AMB misalignments.

Field dynamic balancing for active magnetic bearings supporting rigid rotor shaft based on extended state observer

2021 ◽  
Vol 158 ◽  
pp. 107801
Author(s):  
Kexiang Li ◽  
Cong Peng ◽  
Zhiquan Deng ◽  
Wei Huang ◽  
Zhongming Zhang
Keyword(s):  
State Observer ◽  
Extended State Observer ◽  
Magnetic Bearings ◽  
Rigid Rotor ◽  
Active Magnetic Bearings ◽  
Extended State ◽  
Dynamic Balancing ◽  
Rotor Shaft ◽  
Field Dynamic ◽  
Field Dynamic Balancing

Nonlinear Analysis of a Rigid Rotor on Magnetic Bearings

1995 ◽  
Author(s):  
C. Nataraj
Keyword(s):  
Nonlinear Analysis ◽  
Equations Of Motion ◽  
Forced Response ◽  
Magnetic Bearings ◽  
Rigid Rotor ◽  
Stability Criteria ◽  
Safe Operation ◽  
Qualitative And Quantitative ◽  
Quantitative Results ◽  
Nonlinear Equations Of Motion

A simple model of a rigid rotor supported on magnetic bearings is considered. A proportional control architecture is assumed, the nonlinear equations of motion are derived and some essential nondimensional parameters are identified. The free and forced response of the system is analyzed using techniques of nonlinear analysis. Both qualitative and quantitative results are obtained and stability criteria are derived for safe operation of the system.

Characteristic Parameters Estimation of Active Magnetic Bearings in a Coupled Rotor System

2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Sampath Kumar Kuppa ◽  
Mohit Lal
Keyword(s):  
Numerical Technique ◽  
Forced Response ◽  
Rotor System ◽  
Parameters Estimation ◽  
Magnetic Bearings ◽  
Fast Fourier Transformation ◽  
Active Magnetic Bearings ◽  
Least Squares Regression ◽  
Characteristic Parameters ◽  
Full Spectrum

Abstract Present research inspects the performance of rotor–bearing–coupling system in the presence of active magnetic bearings (AMBs). A methodology is suggested to quantify various fault characteristics along with AMB characteristic parameters of a coupled turbine generator system. A simplest possible turbogenerator system is modeled to analyze coupling misalignment. Conventional methodology to estimate dynamic system parameters based on forced response information is not enough for AMB-integrated rotor system because it requires current information along with displacement information. The controlling current of AMB is tuned and controlled with a controller of proportional–integral–derivative (PID) type. A numerical technique (Lagrange's equation) is applied to get equations of motion (EOM). Runge–Kutta technique is used to obtain EOM to acquire the time domain responses. The fast Fourier transformation (FFT) is applied on obtained responses to acquire responses in the frequency domain, and full spectrum technique is applied to propose the methodology. A methodology that depends on the least squares regression approach is proposed to evaluate the multifault parameters of AMB-integrated rotor system. The robustness of the algorithm is checked against various levels of noise and modeling error and observed efficient. An appreciable reduction in misalignment forces and moments is observed by using AMBs.

Adaptive Vibration Control of a Rigid Rotor Supported by Active Magnetic Bearings

1996 ◽  
Vol 118 (4) ◽  
pp. 825-829 ◽  
Author(s):  
O. Lang ◽  
J. Wassermann ◽  
H. Springer
Keyword(s):  
Numerical Simulation ◽  
Cross Coupling ◽  
Least Square ◽  
Magnetic Bearings ◽  
Pole Placement ◽  
Rigid Rotor ◽  
Active Magnetic Bearings ◽  
Coupling Coefficients ◽  
Least Square Estimator ◽  
Response Characteristics

In this paper a digital numerical simulation is carried out in which active magnetic bearings (AMB) are applied to control nonlinear and nonsynchronous vibrations of a rigid rotor excited by nonconservative cross-coupling mechanisms. Through an adaptive control algorithm of the AMB controller, unknown cross-coupling parameters of a rotor are estimated on-line by a standard least-square estimator along with a time-varying so-called forgetting factor. The parameters of the AMB controller are adapted in order to compensate for the cross-coupling effects and to stabilize the rotor system. Transient cross-coupling response characteristics are calculated by numerical simulation of a rigid rotor supported by two active magnetic bearings. With this kind of control strategy, the stability of the system can be guaranteed for much higher values of cross-coupling coefficients than with common nonadaptive feedback controllers, designed with pole placement or least square algorithms.

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